Dépouillements

New directions in flotation machine design / Graeme J. Jameson in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 835–841 Titre : New directions in flotation machine design Type de document : texte imprimé Auteurs : Graeme J. Jameson, Auteur Année de publication : 2011 Article en page(s) : pp. 835–841 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  machines  Fine  particle  processing  Flotation  bubbles  Flotation  kinetics Résumé : The theoretical background for flotation kinetics of ultrafine and coarse particles are explored. Recent advances in flotation technology for these difficult areas are reviewed, with a focus on improving the flotation rate of ultrafines, and extending the upper limit for coarse particle flotation. For ultra-fine particles, the theory suggests that the rate of flotation can be improved by increasing the rate of shear in the suspension of particles and bubbles. A new cell has been developed, the Concorde Cell, in which the pre-aerated feed is raised to supersonic velocities before passing into a high-shear zone in the flotation cell. The local dissipation rate is of the order of 100 kW/m3, one to two orders of magnitude higher than is available in conventional mechanical cells. The Concorde Cell has been trialed on a finely ground PGM feed in South Africa, with excellent results. By recycling the tailings, and using the mass pull or solids recovery as the control variable, the Cell is capable of producing a high-grade concentrate at high recoveries, over a wide range of particle sizes. Theory for the upper limit of coarse particle flotation suggests that a quiescent flow field is necessary to prevent the particles from becoming detached from the bubbles. A liquid-fluidized bed provides a suitable environment. The flotation feed is introduced into the fluidized bed, and air bubbles are dispersed in the fluidizing water. Coarse particles attach to the bubbles rising through the bed and are lifted into the froth layer that is maintained on top of the cell in the usual way. Particles of galena up to 1 mm in diameter have been recovered in such a bed, while for particles of lower density such as quartz and coal, the upper limit for flotation has been extended to at least 2 mm and 5.6 mm respectively. The fluidized bed technology provides major advantages beyond the ability to recover coarse particles currently lost in existing operations. Thus, if the upper flotation limit can be extended, the top size for grinding can be raised, with significant reductions in energy costs. Liberation of the values is the key limitation. Also, a fluidized bed flotation cell can accept a feed with much higher percent solids, leading to significant reductions in water requirements. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001093 [article] New directions in flotation machine design [texte imprimé] / Graeme J. Jameson, Auteur . - 2011 . - pp. 835–841. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 835–841 Mots-clés : Froth  flotation  Flotation  machines  Fine  particle  processing  Flotation  bubbles  Flotation  kinetics Résumé : The theoretical background for flotation kinetics of ultrafine and coarse particles are explored. Recent advances in flotation technology for these difficult areas are reviewed, with a focus on improving the flotation rate of ultrafines, and extending the upper limit for coarse particle flotation. For ultra-fine particles, the theory suggests that the rate of flotation can be improved by increasing the rate of shear in the suspension of particles and bubbles. A new cell has been developed, the Concorde Cell, in which the pre-aerated feed is raised to supersonic velocities before passing into a high-shear zone in the flotation cell. The local dissipation rate is of the order of 100 kW/m3, one to two orders of magnitude higher than is available in conventional mechanical cells. The Concorde Cell has been trialed on a finely ground PGM feed in South Africa, with excellent results. By recycling the tailings, and using the mass pull or solids recovery as the control variable, the Cell is capable of producing a high-grade concentrate at high recoveries, over a wide range of particle sizes. Theory for the upper limit of coarse particle flotation suggests that a quiescent flow field is necessary to prevent the particles from becoming detached from the bubbles. A liquid-fluidized bed provides a suitable environment. The flotation feed is introduced into the fluidized bed, and air bubbles are dispersed in the fluidizing water. Coarse particles attach to the bubbles rising through the bed and are lifted into the froth layer that is maintained on top of the cell in the usual way. Particles of galena up to 1 mm in diameter have been recovered in such a bed, while for particles of lower density such as quartz and coal, the upper limit for flotation has been extended to at least 2 mm and 5.6 mm respectively. The fluidized bed technology provides major advantages beyond the ability to recover coarse particles currently lost in existing operations. Thus, if the upper flotation limit can be extended, the top size for grinding can be raised, with significant reductions in energy costs. Liberation of the values is the key limitation. Also, a fluidized bed flotation cell can accept a feed with much higher percent solids, leading to significant reductions in water requirements. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001093

Iron ore slimes flotation / L. Rocha in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 842–845 Titre : Iron ore slimes flotation Type de document : texte imprimé Auteurs : L. Rocha, Auteur ; R. Z. L. Cançado, Auteur ; A.E.C. Peres, Auteur Année de publication : 2011 Article en page(s) : pp. 842–845 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Column  flotation  Flotation  depressants  Flotation  collectors Résumé : This investigation addressed the processing of ultrafine tailings (slimes) from an iron ore concentrator via reverse cationic flotation to produce pellet feed fines, despite the traditional view that ultrafine particles do not float. Following size analyses, chemical and mineralogical characterisation, desliming and flotation tests were performed aiming at verifying the flotation behaviour of the slimes. Different dosages of collector and depressant were used. The promising results of the laboratory scale tests led to carrying out pilot scale tests with the currently produced slimes, and the slimes that will be generated in the future, after the commissioning of the mining company’s expansion project. It was observed that a reverse cationic column flotation process, using high depressant dosage, was selective, yielding high grade concentrates with low impurity content at high levels of iron recovery, approximately 60% mass recovery and 80% metallic recovery in the flotation stage. Excellent valuable product grade (less than 1% silica) and reject product grade (approximately 12% iron) were achieved, resulting in high selectivity levels. The overall mass recovery reached 20%. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000658 [article] Iron ore slimes flotation [texte imprimé] / L. Rocha, Auteur ; R. Z. L. Cançado, Auteur ; A.E.C. Peres, Auteur . - 2011 . - pp. 842–845. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 842–845 Mots-clés : Column  flotation  Flotation  depressants  Flotation  collectors Résumé : This investigation addressed the processing of ultrafine tailings (slimes) from an iron ore concentrator via reverse cationic flotation to produce pellet feed fines, despite the traditional view that ultrafine particles do not float. Following size analyses, chemical and mineralogical characterisation, desliming and flotation tests were performed aiming at verifying the flotation behaviour of the slimes. Different dosages of collector and depressant were used. The promising results of the laboratory scale tests led to carrying out pilot scale tests with the currently produced slimes, and the slimes that will be generated in the future, after the commissioning of the mining company’s expansion project. It was observed that a reverse cationic column flotation process, using high depressant dosage, was selective, yielding high grade concentrates with low impurity content at high levels of iron recovery, approximately 60% mass recovery and 80% metallic recovery in the flotation stage. Excellent valuable product grade (less than 1% silica) and reject product grade (approximately 12% iron) were achieved, resulting in high selectivity levels. The overall mass recovery reached 20%. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000658

A comparison of the flotation behaviour and the effect of copper activation on three reef types from the Merensky reef at Northam / C. P. Brough in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 846–854 Titre : A comparison of the flotation behaviour and the effect of copper activation on three reef types from the Merensky reef at Northam Type de document : texte imprimé Auteurs : C. P. Brough, Auteur ; D. J. Bradshaw, Auteur ; M. Becker, Auteur Année de publication : 2011 Article en page(s) : pp. 846–854 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : PGM  ores  Sulfide  minerals  Pyrrhotite  Mineralogy Résumé : At Northam Platinum Mine in South Africa intense potholing of the Merensky Reef has led to the development of several mineralogically different reef types in proximity to one other, which results in differing processing performance. In particular, the nature and texture of the valuable sulfide minerals, as well as the nature of the gangue minerals and degree of alteration in the various reef types affects both milling throughput and flotation recovery. The three major ore types being processed and thus selected for this study are the Normal reef, NP2 reef and P2 reef. The focus of this study was to investigate the relationship between changes in mineralogy and the effect of copper sulfate addition at two grind sizes on the laboratory batch flotation performance obtained with the three reef types. The best results were obtained with the NP2 reef in terms of expected industrial throughput, recovery and grade of all base-metal sulfides despite this reef type having the lowest feed grade of sulfide minerals. The biggest difference was in the recovery and grade of pyrrhotite. The better performance of the NP2 reef ore relative to the Normal and P2 reefs has been attributed to the equigranular nature of the reef type together with its feldspathic mineralogy. In contrast, the Normal and P2 reefs are orthopyroxene rich and are associated with more alteration minerals. The Normal reef contained the greatest amount of alteration minerals which correlated to the poorest flotation performance in terms of recovery and grade at all conditions tested. Whereas addition of copper sulfate did not affect the flotation of the sulfides in the NP2 reef ore, it significantly improved the overall performance of the base-metal sulfides in the Normal and P2 reefs, especially for pyrrhotite. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000944 [article] A comparison of the flotation behaviour and the effect of copper activation on three reef types from the Merensky reef at Northam [texte imprimé] / C. P. Brough, Auteur ; D. J. Bradshaw, Auteur ; M. Becker, Auteur . - 2011 . - pp. 846–854. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 846–854 Mots-clés : PGM  ores  Sulfide  minerals  Pyrrhotite  Mineralogy Résumé : At Northam Platinum Mine in South Africa intense potholing of the Merensky Reef has led to the development of several mineralogically different reef types in proximity to one other, which results in differing processing performance. In particular, the nature and texture of the valuable sulfide minerals, as well as the nature of the gangue minerals and degree of alteration in the various reef types affects both milling throughput and flotation recovery. The three major ore types being processed and thus selected for this study are the Normal reef, NP2 reef and P2 reef. The focus of this study was to investigate the relationship between changes in mineralogy and the effect of copper sulfate addition at two grind sizes on the laboratory batch flotation performance obtained with the three reef types. The best results were obtained with the NP2 reef in terms of expected industrial throughput, recovery and grade of all base-metal sulfides despite this reef type having the lowest feed grade of sulfide minerals. The biggest difference was in the recovery and grade of pyrrhotite. The better performance of the NP2 reef ore relative to the Normal and P2 reefs has been attributed to the equigranular nature of the reef type together with its feldspathic mineralogy. In contrast, the Normal and P2 reefs are orthopyroxene rich and are associated with more alteration minerals. The Normal reef contained the greatest amount of alteration minerals which correlated to the poorest flotation performance in terms of recovery and grade at all conditions tested. Whereas addition of copper sulfate did not affect the flotation of the sulfides in the NP2 reef ore, it significantly improved the overall performance of the base-metal sulfides in the Normal and P2 reefs, especially for pyrrhotite. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000944

A case study of optimising UG2 flotation performance / Martyn P. Hay in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 855–867 Titre : A case study of optimising UG2 flotation performance : Part 1: Bench, pilot and plant scale factors which influence Cr2O3 entrainment in UG2 flotation Type de document : texte imprimé Auteurs : Martyn P. Hay, Auteur ; Ravi Roy, Auteur Année de publication : 2011 Article en page(s) : pp. 855–867 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  kinetics  Modelling  Process  optimisation Résumé : In the Platinum Group Minerals (PGM) industry, almost all UG2 deposits being currently developed are deep level and bankable feasibility studies must rely entirely on batch testwork of borecore samples. Since UG2 has a significant chromite (FeO·Cr2O3) content, minimising chromium oxide (Cr2O3) recovery into final concentrate has become a critical aspect of downstream smelting since % Cr2O3 in furnace feed has a practical upper limit of about 2.5%. In most cases concentrate is toll smelted but penalties are severe depending on chromite content. Together with PGMs, the characterisation of chromite floatability and prediction of recovery and concentrate grade in a production plant using bench-scale data is therefore a key component of UG2 ore analysis. The need to accurately predict chromite recovery and particularly to identify characteristics that indicate when % Cr2O3 in concentrate can be reduced has a significant impact on the project’s financials and subsequent plant design. The natural floatability of chromite is low and its passage into concentrate is almost entirely by entrainment in water carry-over into concentrate whereas PGMs are recovered by true flotation. Optimising flotation performance has to accommodate these two completely different flotation behaviours in an effort to reject chromite whilst at the same time maximise Platinum Group Minerals (PGM) recovery and grade. Incorporating extensive testwork conducted by Barrick Platinum South Africa and Northam and other plant data, the paper traces chromite, and to a lesser extent PGM, floatability in bench, pilot and plant scales and highlights that certain mechanisms of chromite entrainment are consistent irrespective of cell size and efficiency. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001214 [article] A case study of optimising UG2 flotation performance : Part 1: Bench, pilot and plant scale factors which influence Cr2O3 entrainment in UG2 flotation [texte imprimé] / Martyn P. Hay, Auteur ; Ravi Roy, Auteur . - 2011 . - pp. 855–867. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 855–867 Mots-clés : Froth  flotation  Flotation  kinetics  Modelling  Process  optimisation Résumé : In the Platinum Group Minerals (PGM) industry, almost all UG2 deposits being currently developed are deep level and bankable feasibility studies must rely entirely on batch testwork of borecore samples. Since UG2 has a significant chromite (FeO·Cr2O3) content, minimising chromium oxide (Cr2O3) recovery into final concentrate has become a critical aspect of downstream smelting since % Cr2O3 in furnace feed has a practical upper limit of about 2.5%. In most cases concentrate is toll smelted but penalties are severe depending on chromite content. Together with PGMs, the characterisation of chromite floatability and prediction of recovery and concentrate grade in a production plant using bench-scale data is therefore a key component of UG2 ore analysis. The need to accurately predict chromite recovery and particularly to identify characteristics that indicate when % Cr2O3 in concentrate can be reduced has a significant impact on the project’s financials and subsequent plant design. The natural floatability of chromite is low and its passage into concentrate is almost entirely by entrainment in water carry-over into concentrate whereas PGMs are recovered by true flotation. Optimising flotation performance has to accommodate these two completely different flotation behaviours in an effort to reject chromite whilst at the same time maximise Platinum Group Minerals (PGM) recovery and grade. Incorporating extensive testwork conducted by Barrick Platinum South Africa and Northam and other plant data, the paper traces chromite, and to a lesser extent PGM, floatability in bench, pilot and plant scales and highlights that certain mechanisms of chromite entrainment are consistent irrespective of cell size and efficiency. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001214

A case study of optimising UG2 flotation performance / Martyn P. Hay in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 868–876 Titre : A case study of optimising UG2 flotation performance : Part 2: Modelling improved PGM recovery and Cr2O3 rejection at Northam’s UG2 concentrator Type de document : texte imprimé Auteurs : Martyn P. Hay, Auteur Année de publication : 2011 Article en page(s) : pp. 868–876 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  kinetics  Modelling  Process  optimisation Résumé : In Part 1 of this 2 part series of papers the relationships between Platinum Group Metals (PGM), mass and water recovery and %Cr2O3 (as chromite) in concentrate were defined for laboratory, pilot and plant scales. The entrainment of chromite in final concentrate was shown to be related to its slow floating kinetics. In 2004, Northam Platinum mine embarked upon an upgrading program on its UG2 plant which included the installation of two column cells with external spargers as final cleaners. Optimisation resulted in a PGM recovery increase of 6% whilst %Cr2O3 in final concentrate was reduced from 4.0% to 2.2%. In this second paper, the Northam circuit is modelled before and after modification and installation of the final cleaner column cells. Simulation shows that the external sparger, driven by a dedicated recirculation pump, imparts energy into the system and provides the column with a PGM recovery capability equal to that of a mechanically driven cell. The deep froth bed of the columns enhances chromite rejection. As a result of this, greater operating flexibility has allowed PGM recovery at Northam to be increased by increasing mass pull whilst at the same time reducing %Cr2O3 in concentrate. Modelling shows that Northam’s reduction in %Cr2O3 can be fully described by reducing only the laboratory to plant scale-up factor for slow floating rate of chromite by 25%, whilst leaving the normal scale-up factors for fast floating fraction and rate unchanged. The improvement in PGM recovery was simulated using the same set of rougher and cleaner feed PGM kinetics and scale-up factors. This suggests that chromite entrainment is modelled via its slow floating rate and PGM recovery by true flotation is primarily modelled via its fast floating fraction and rate. Floatable gangue is modelled via its full set of fast and slow kinetics as its passage into final concentrate (and cleaner tailings circulating load) is a mix of true flotation and entrainment. This case study shows that a standard flotation circuit and one incorporating Northam’s column cell may be predicted from laboratory scale rate tests and flotation kinetics. The impact of Northam’s technology on other UG2 ores may be predicted by applying the change in chromite scale-up factors determined by simulation. The degree of improvement is dependant on the ore’s mineralogy and specifically its selectivity between PGM minerals, chromite and floatable gangue. This is illustrated by simulating the impact of the Northam column cell on Barrick’s Sedibelo UG2 ore. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001482 [article] A case study of optimising UG2 flotation performance : Part 2: Modelling improved PGM recovery and Cr2O3 rejection at Northam’s UG2 concentrator [texte imprimé] / Martyn P. Hay, Auteur . - 2011 . - pp. 868–876. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 868–876 Mots-clés : Froth  flotation  Flotation  kinetics  Modelling  Process  optimisation Résumé : In Part 1 of this 2 part series of papers the relationships between Platinum Group Metals (PGM), mass and water recovery and %Cr2O3 (as chromite) in concentrate were defined for laboratory, pilot and plant scales. The entrainment of chromite in final concentrate was shown to be related to its slow floating kinetics. In 2004, Northam Platinum mine embarked upon an upgrading program on its UG2 plant which included the installation of two column cells with external spargers as final cleaners. Optimisation resulted in a PGM recovery increase of 6% whilst %Cr2O3 in final concentrate was reduced from 4.0% to 2.2%. In this second paper, the Northam circuit is modelled before and after modification and installation of the final cleaner column cells. Simulation shows that the external sparger, driven by a dedicated recirculation pump, imparts energy into the system and provides the column with a PGM recovery capability equal to that of a mechanically driven cell. The deep froth bed of the columns enhances chromite rejection. As a result of this, greater operating flexibility has allowed PGM recovery at Northam to be increased by increasing mass pull whilst at the same time reducing %Cr2O3 in concentrate. Modelling shows that Northam’s reduction in %Cr2O3 can be fully described by reducing only the laboratory to plant scale-up factor for slow floating rate of chromite by 25%, whilst leaving the normal scale-up factors for fast floating fraction and rate unchanged. The improvement in PGM recovery was simulated using the same set of rougher and cleaner feed PGM kinetics and scale-up factors. This suggests that chromite entrainment is modelled via its slow floating rate and PGM recovery by true flotation is primarily modelled via its fast floating fraction and rate. Floatable gangue is modelled via its full set of fast and slow kinetics as its passage into final concentrate (and cleaner tailings circulating load) is a mix of true flotation and entrainment. This case study shows that a standard flotation circuit and one incorporating Northam’s column cell may be predicted from laboratory scale rate tests and flotation kinetics. The impact of Northam’s technology on other UG2 ores may be predicted by applying the change in chromite scale-up factors determined by simulation. The degree of improvement is dependant on the ore’s mineralogy and specifically its selectivity between PGM minerals, chromite and floatable gangue. This is illustrated by simulating the impact of the Northam column cell on Barrick’s Sedibelo UG2 ore. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001482

A novel scale-up approach for mechanical flotation cells / J. Yianatos in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 877–884 Titre : A novel scale-up approach for mechanical flotation cells Type de document : texte imprimé Auteurs : J. Yianatos, Auteur ; F. Contreras, Auteur ; P. Morales, Auteur Année de publication : 2011 Article en page(s) : pp. 877–884 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  cells  Modeling  Scale-up  Simulation  Flotation  rate Résumé : Planning industrial flotation operation and earlier flotation equipment sizing are commonly based on batch flotation testing, where ideal operating conditions can be provided. Each plant has its own batch flotation standards and typically uses a time scale-up factor in order to compare laboratory and plant flotation performance. However, flotation scale-up is more complex, and it is not yet completely understood. In this work, a novel scale-up approach was developed, where the effects of the hydrodynamic regime (mixing), solid segregation (effective residence time) and froth recovery on the plant flotation rate were identified and evaluated. Each effect was then described by means of correction factors applied on the batch flotation rate, which was considered the optimal condition. These factors can be determined from laboratory and plant experimental data. This methodology was successfully applied at the rougher copper flotation plant of Codelco Norte Division, Codelco-Chile, for cells of 160 and 300 m3. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001251 [article] A novel scale-up approach for mechanical flotation cells [texte imprimé] / J. Yianatos, Auteur ; F. Contreras, Auteur ; P. Morales, Auteur . - 2011 . - pp. 877–884. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 877–884 Mots-clés : Flotation  cells  Modeling  Scale-up  Simulation  Flotation  rate Résumé : Planning industrial flotation operation and earlier flotation equipment sizing are commonly based on batch flotation testing, where ideal operating conditions can be provided. Each plant has its own batch flotation standards and typically uses a time scale-up factor in order to compare laboratory and plant flotation performance. However, flotation scale-up is more complex, and it is not yet completely understood. In this work, a novel scale-up approach was developed, where the effects of the hydrodynamic regime (mixing), solid segregation (effective residence time) and froth recovery on the plant flotation rate were identified and evaluated. Each effect was then described by means of correction factors applied on the batch flotation rate, which was considered the optimal condition. These factors can be determined from laboratory and plant experimental data. This methodology was successfully applied at the rougher copper flotation plant of Codelco Norte Division, Codelco-Chile, for cells of 160 and 300 m3. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001251

Effect of air distribution profile on selectivity at zinc cleaner circuit / Alp Aslan in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 885–887 Titre : Effect of air distribution profile on selectivity at zinc cleaner circuit Type de document : texte imprimé Auteurs : Alp Aslan, Auteur ; Hakkı Boz, Auteur Année de publication : 2011 Article en page(s) : pp. 885–887 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  kinetics  Sulphide  ores Résumé : Airflow rate to a cell is one of the main operating variables in flotation. In many plants, if measurements are available at all, they are typically made on a line common to several cells with valves to distribute as determined by the operator. In this study, air distribution throughout zinc cleaner circuit of CBI was adjusted to three different profiles. These are “as found” which was the original profile adjusted by operators, “decreasing” and “increasing” profiles which were adjusted for test. It was seen that air distribution profile significantly affected flotation selectivity. Selectivity between both sphalerite–pyrite and sphalerite–chalcopyrite increased with “increasing” profile. The effect of air distribution profile on flotation selectivity was also studied at mini pilot plant (MPP). Zinc rougher concentrate was taken as feed of MPP. Air distribution profile was adjusted and controlled by airflow meters of each cell. Three different air profiles; “balanced”, “decreasing” and “increasing”, were tested. The results of MPP tests also confirmed that “increasing” air distribution profile improved selectivity at zinc cleaner circuit. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001937 [article] Effect of air distribution profile on selectivity at zinc cleaner circuit [texte imprimé] / Alp Aslan, Auteur ; Hakkı Boz, Auteur . - 2011 . - pp. 885–887. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 885–887 Mots-clés : Froth  flotation  Flotation  kinetics  Sulphide  ores Résumé : Airflow rate to a cell is one of the main operating variables in flotation. In many plants, if measurements are available at all, they are typically made on a line common to several cells with valves to distribute as determined by the operator. In this study, air distribution throughout zinc cleaner circuit of CBI was adjusted to three different profiles. These are “as found” which was the original profile adjusted by operators, “decreasing” and “increasing” profiles which were adjusted for test. It was seen that air distribution profile significantly affected flotation selectivity. Selectivity between both sphalerite–pyrite and sphalerite–chalcopyrite increased with “increasing” profile. The effect of air distribution profile on flotation selectivity was also studied at mini pilot plant (MPP). Zinc rougher concentrate was taken as feed of MPP. Air distribution profile was adjusted and controlled by airflow meters of each cell. Three different air profiles; “balanced”, “decreasing” and “increasing”, were tested. The results of MPP tests also confirmed that “increasing” air distribution profile improved selectivity at zinc cleaner circuit. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001937

Estimation of the actual bubble surface area flux in flotation / J. Leiva in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 888–894 Titre : Estimation of the actual bubble surface area flux in flotation Type de document : texte imprimé Auteurs : J. Leiva, Auteur ; L. Vinnett, Auteur ; F. Contreras, Auteur Année de publication : 2011 Article en page(s) : pp. 888–894 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  bubbles  Flotation  frothers  Sampling  Modeling Résumé : The bubble surface area flux, SB, defined as the ration between the superficial gas rate JG and the Sauter mean bubble diameter D32, has been widely used to describe the gas phase dispersion efficiency in flotation machines, and from this predict flotation performance, notable mineral recovery to forecast plant economics. In this work, results of bubble size distribution (BSD) generated in a pilot column are analyzed. Using video and image analysis techniques, the impact of different sampling rates on the BSD was evaluated. Measurements were carried out for D32 = 1–2 mm, JG = 0.5–1.5 cm/s and two frother concentration, with a maximum sampling rate of 100 fps. In addition, the bubble rise velocity in the bubble swarm was measured, as a function of the individual bubble diameter, for different operational conditions. The identification of the BSD depends on the proper selection of the visual field and sampling rate for acquisition and processing of bubble images. Distortion in the estimation occurs because a larger holdup of small bubbles is observed, relative to the overall data set, due to their lower velocity. The actual BSD was obtained by correcting the observed population, considering the effect of bubble rise velocity. Thus, the actual bubble surface area flux, SB, was calculated. The results were evaluated at a pilot scale (air–water system) as well as an industrial plant scale (air-pulp system). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000257 [article] Estimation of the actual bubble surface area flux in flotation [texte imprimé] / J. Leiva, Auteur ; L. Vinnett, Auteur ; F. Contreras, Auteur . - 2011 . - pp. 888–894. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 888–894 Mots-clés : Froth  flotation  Flotation  bubbles  Flotation  frothers  Sampling  Modeling Résumé : The bubble surface area flux, SB, defined as the ration between the superficial gas rate JG and the Sauter mean bubble diameter D32, has been widely used to describe the gas phase dispersion efficiency in flotation machines, and from this predict flotation performance, notable mineral recovery to forecast plant economics. In this work, results of bubble size distribution (BSD) generated in a pilot column are analyzed. Using video and image analysis techniques, the impact of different sampling rates on the BSD was evaluated. Measurements were carried out for D32 = 1–2 mm, JG = 0.5–1.5 cm/s and two frother concentration, with a maximum sampling rate of 100 fps. In addition, the bubble rise velocity in the bubble swarm was measured, as a function of the individual bubble diameter, for different operational conditions. The identification of the BSD depends on the proper selection of the visual field and sampling rate for acquisition and processing of bubble images. Distortion in the estimation occurs because a larger holdup of small bubbles is observed, relative to the overall data set, due to their lower velocity. The actual BSD was obtained by correcting the observed population, considering the effect of bubble rise velocity. Thus, the actual bubble surface area flux, SB, was calculated. The results were evaluated at a pilot scale (air–water system) as well as an industrial plant scale (air-pulp system). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000257

A potential application of collectorless flotation in a copper/gold operation / X. Zheng in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 895–902 Titre : A potential application of collectorless flotation in a copper/gold operation Type de document : texte imprimé Auteurs : X. Zheng, Auteur ; P. Manton, Auteur Année de publication : 2011 Article en page(s) : pp. 895–902 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  collectors Résumé : A recent study found that chalcopyrite in the Telfer ore could float without a collector whilst pyrite did not float without a collector in the laboratory. In comparison of the flotation result with and without a collector, the two grade–recovery curves are clearly separated due mainly to less pyrite recovery and higher concentrate grades produced by collectorless flotation. Pre-aeration tended to promote collectorless flotation of chalcopyrite while it had a negligible effect on pyrite flotation. In addition to the laboratory study, pulp potential measurements were conducted in the plant. The results indicate that chalcopyrite is likely to retain its collectorless floatability after SAG milling. This may provide an opportunity of using a flash unit for collectorless flotation on the SAG mill discharge stream. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000403 [article] A potential application of collectorless flotation in a copper/gold operation [texte imprimé] / X. Zheng, Auteur ; P. Manton, Auteur . - 2011 . - pp. 895–902. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 895–902 Mots-clés : Froth  flotation  Flotation  collectors Résumé : A recent study found that chalcopyrite in the Telfer ore could float without a collector whilst pyrite did not float without a collector in the laboratory. In comparison of the flotation result with and without a collector, the two grade–recovery curves are clearly separated due mainly to less pyrite recovery and higher concentrate grades produced by collectorless flotation. Pre-aeration tended to promote collectorless flotation of chalcopyrite while it had a negligible effect on pyrite flotation. In addition to the laboratory study, pulp potential measurements were conducted in the plant. The results indicate that chalcopyrite is likely to retain its collectorless floatability after SAG milling. This may provide an opportunity of using a flash unit for collectorless flotation on the SAG mill discharge stream. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000403

An impedance study of the adsorption of CuSO4 and SIBX on pyrrhotite samples of different provenances / Z. Ekmekçi in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 903–907 Titre : An impedance study of the adsorption of CuSO4 and SIBX on pyrrhotite samples of different provenances Type de document : texte imprimé Auteurs : Z. Ekmekçi, Auteur ; M. Becker, Auteur ; E. Bagci Tekes, Auteur Année de publication : 2011 Article en page(s) : pp. 903–907 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulfide  ores  Froth  flotation  Redox  reactions  Electrochemical  impedance  analysis Résumé : The non-stoichiometric sulfide mineral pyrrhotite (Fe(1−x)S), common to many nickel ore deposits, occurs in differing crystallographic forms and compositions. The processing of pyrrhotite from these ores through froth flotation is based on the surface properties of the sulfides and since pyrrhotite is a metallic conductor, it is of interest to characterise the surface properties of pyrrhotite with respect to its electrochemical state. In this study, a series of pyrrhotite samples derived from Canada, South Africa, and Botswana whose mineralogy is well characterised, were used for electrochemical impedance spectroscopy (EIS). The behaviour of the different pyrrhotite samples were compared in terms of the effect of pH (7 and 10), collector addition (SIBX) and copper activation and the results correlated with microflotation tests. The EIS results were then used to interpret and understand the differences in flotation performance of the pyrrhotite samples under the different reagent conditions and provide some answers as to why the success of copper activation on pyrrhotite is so variable. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000439 [article] An impedance study of the adsorption of CuSO4 and SIBX on pyrrhotite samples of different provenances [texte imprimé] / Z. Ekmekçi, Auteur ; M. Becker, Auteur ; E. Bagci Tekes, Auteur . - 2011 . - pp. 903–907. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 903–907 Mots-clés : Sulfide  ores  Froth  flotation  Redox  reactions  Electrochemical  impedance  analysis Résumé : The non-stoichiometric sulfide mineral pyrrhotite (Fe(1−x)S), common to many nickel ore deposits, occurs in differing crystallographic forms and compositions. The processing of pyrrhotite from these ores through froth flotation is based on the surface properties of the sulfides and since pyrrhotite is a metallic conductor, it is of interest to characterise the surface properties of pyrrhotite with respect to its electrochemical state. In this study, a series of pyrrhotite samples derived from Canada, South Africa, and Botswana whose mineralogy is well characterised, were used for electrochemical impedance spectroscopy (EIS). The behaviour of the different pyrrhotite samples were compared in terms of the effect of pH (7 and 10), collector addition (SIBX) and copper activation and the results correlated with microflotation tests. The EIS results were then used to interpret and understand the differences in flotation performance of the pyrrhotite samples under the different reagent conditions and provide some answers as to why the success of copper activation on pyrrhotite is so variable. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000439

The effect of grinding environment on flotation of sulphide poor PGE ores / Tomi Maksimainen in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 908–914 Titre : The effect of grinding environment on flotation of sulphide poor PGE ores Type de document : texte imprimé Auteurs : Tomi Maksimainen, Auteur ; Saija Luukkanen, Auteur ; Pekka Mörsky, Auteur Année de publication : 2011 Article en page(s) : pp. 908–914 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Precious  metal  ores  Grinding  Froth  flotation Résumé : The effects of grinding media and pulp chemistry may have significant effects on floatability of sulphide ores. Grinding in mild steel mill is suggested to cause reducing environment, galvanic interactions and formation of surface hydroxides which suppress sulphide flotation. In this study the influence of grinding environment on floatability of two Finnish PGE ores with low sulphur content has been studied. Variables in the study were grinding atmosphere (CO2, N2 and air) and grinding media. The effect of addition of lime into mill was tested as a reference. It was found that CO2 atmosphere in grinding clearly improved both PGM grade and recovery in flotation of the ore with lower sulphide content. Platinum selectivity was improved also with the other ore but recovery was similar to the other tests. Grinding in CO2 atmosphere seems to diminish the oxidation which assists upgrading of platinum group minerals. It is also proposed that impact of CO2 may result from formation of hydrophilic carbonates on mineral surfaces. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000579 [article] The effect of grinding environment on flotation of sulphide poor PGE ores [texte imprimé] / Tomi Maksimainen, Auteur ; Saija Luukkanen, Auteur ; Pekka Mörsky, Auteur . - 2011 . - pp. 908–914. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 908–914 Mots-clés : Precious  metal  ores  Grinding  Froth  flotation Résumé : The effects of grinding media and pulp chemistry may have significant effects on floatability of sulphide ores. Grinding in mild steel mill is suggested to cause reducing environment, galvanic interactions and formation of surface hydroxides which suppress sulphide flotation. In this study the influence of grinding environment on floatability of two Finnish PGE ores with low sulphur content has been studied. Variables in the study were grinding atmosphere (CO2, N2 and air) and grinding media. The effect of addition of lime into mill was tested as a reference. It was found that CO2 atmosphere in grinding clearly improved both PGM grade and recovery in flotation of the ore with lower sulphide content. Platinum selectivity was improved also with the other ore but recovery was similar to the other tests. Grinding in CO2 atmosphere seems to diminish the oxidation which assists upgrading of platinum group minerals. It is also proposed that impact of CO2 may result from formation of hydrophilic carbonates on mineral surfaces. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000579

Investigation into the flotation response of a sulphide ore to depressant mixtures / K.C. Corin in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 915–920 Titre : Investigation into the flotation response of a sulphide ore to depressant mixtures Type de document : texte imprimé Auteurs : K.C. Corin, Auteur ; P.J. Harris, Auteur Année de publication : 2011 Article en page(s) : pp. 915–920 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulphide  ores  Froth  flotation  Flotation  depressants Résumé : The Merensky reef in the Bushveld Complex is well-known to contain a number of platinum group elements (PGEs). These PGEs are strongly associated with the sulphide minerals found in the Merensky reef. In order to recover the PGEs from the Merensky reef, a combination of reagents is used to optimise the flotation process by various operations across the Bushveld Complex. These reagents usually include; collectors, activators and depressants. The most common collectors are the xanthates, while the activator copper sulphate (CuSO4) is most often used. The depressants, either carboxymethylcellulose (CMC) or modified guar gum (guar) are typical. This study examines the effect of blending depressants on the flotation response of a typical Merensky ore. The effect of each depressant, being guar and CMC, was examined in turn by changing the concentrations used in initial flotation tests; this was followed by blending guar and CMC in equal ratios by various procedures to determine the effects thereof. The depressants were blended in two ways: (1) premixed followed by a single conditioning stage and (2) stage wise; as primary and secondary depressants, each conditioned in turn. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000580 [article] Investigation into the flotation response of a sulphide ore to depressant mixtures [texte imprimé] / K.C. Corin, Auteur ; P.J. Harris, Auteur . - 2011 . - pp. 915–920. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 915–920 Mots-clés : Sulphide  ores  Froth  flotation  Flotation  depressants Résumé : The Merensky reef in the Bushveld Complex is well-known to contain a number of platinum group elements (PGEs). These PGEs are strongly associated with the sulphide minerals found in the Merensky reef. In order to recover the PGEs from the Merensky reef, a combination of reagents is used to optimise the flotation process by various operations across the Bushveld Complex. These reagents usually include; collectors, activators and depressants. The most common collectors are the xanthates, while the activator copper sulphate (CuSO4) is most often used. The depressants, either carboxymethylcellulose (CMC) or modified guar gum (guar) are typical. This study examines the effect of blending depressants on the flotation response of a typical Merensky ore. The effect of each depressant, being guar and CMC, was examined in turn by changing the concentrations used in initial flotation tests; this was followed by blending guar and CMC in equal ratios by various procedures to determine the effects thereof. The depressants were blended in two ways: (1) premixed followed by a single conditioning stage and (2) stage wise; as primary and secondary depressants, each conditioned in turn. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000580

Poly (N-isopropylacrylamide) (PNIPAM) as a flotation collector / Elizaveta Burdukova in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 921–927 Titre : Poly (N-isopropylacrylamide) (PNIPAM) as a flotation collector : Effect of temperature and molecular weight Type de document : texte imprimé Auteurs : Elizaveta Burdukova, Auteur ; Haihong Li, Auteur ; Dee J. Bradshaw, Auteur Année de publication : 2011 Article en page(s) : pp. 921–927 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Mineral  processing  Flotation  reagents  Flotation  collectors  Fine  particle  processing Résumé : Poly (N-isopropylacrylamide) (PNIPAM), a temperature responsive polymer, was tested for its potential use as a collector in a quartz flotation system. The effect of PNIPAM on the surface characteristics of quartz particles were studied using induction time, contact angle and zeta potential measurement and analysed in terms of the probability of bubble/particle attachment and the probability of formation of stable bubble/particle aggregates. It was found that probability of bubble/particle attachment of quartz significantly increases in the presence of PNIPAM, particularly at temperatures above the lower critical solution temperature (LCST) of 32 °C. Furthermore, the probability of bubble/particle attachment increases with increasing PNIPAM molecular weight. This was attributed to the increased hydrophobicity of the quartz surface as well as the decrease in the double layer repulsion between bubbles and particles. This leads to the conclusion that PNIPAM could act as an effective collector in a flotation system. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000592 [article] Poly (N-isopropylacrylamide) (PNIPAM) as a flotation collector : Effect of temperature and molecular weight [texte imprimé] / Elizaveta Burdukova, Auteur ; Haihong Li, Auteur ; Dee J. Bradshaw, Auteur . - 2011 . - pp. 921–927. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 921–927 Mots-clés : Mineral  processing  Flotation  reagents  Flotation  collectors  Fine  particle  processing Résumé : Poly (N-isopropylacrylamide) (PNIPAM), a temperature responsive polymer, was tested for its potential use as a collector in a quartz flotation system. The effect of PNIPAM on the surface characteristics of quartz particles were studied using induction time, contact angle and zeta potential measurement and analysed in terms of the probability of bubble/particle attachment and the probability of formation of stable bubble/particle aggregates. It was found that probability of bubble/particle attachment of quartz significantly increases in the presence of PNIPAM, particularly at temperatures above the lower critical solution temperature (LCST) of 32 °C. Furthermore, the probability of bubble/particle attachment increases with increasing PNIPAM molecular weight. This was attributed to the increased hydrophobicity of the quartz surface as well as the decrease in the double layer repulsion between bubbles and particles. This leads to the conclusion that PNIPAM could act as an effective collector in a flotation system. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000592

Synchrotron XPS, NEXAFS, and ToF-SIMS studies of solution exposed chalcopyrite and heterogeneous chalcopyrite with pyrite / Robert G. Acres in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 928–936 Titre : Synchrotron XPS, NEXAFS, and ToF-SIMS studies of solution exposed chalcopyrite and heterogeneous chalcopyrite with pyrite Type de document : texte imprimé Auteurs : Robert G. Acres, Auteur ; Sarah L. Harmer, Auteur ; David A. Beattie, Auteur Année de publication : 2011 Article en page(s) : pp. 928–936 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulfide  ores  Leaching  Oxidation Résumé : The surface species present on two pure chalcopyrite samples (one with a smooth fracture surface; one with a rough fracture surface) and one heterogeneous sample containing both chalcopyrite and pyrite have been studied using synchrotron X-ray photoelectron spectroscopy (SXPS), near-edge X-ray Absorption Fluorescence Spectroscopy (NEXAFS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The measurements were performed for samples fractured in N2 and for samples subsequently exposed to pH 1 HCl solution for 2 h. The comparison of freshly fractured and solution exposed mineral surfaces has allowed for the investigation of the role of other mineral phases on the development of chalcopyrite surface species, and the role of chalcopyrite grain size on surface species development. Analysis of the chalcopyrite region of each sample indicates that increased surface roughness and the presence of pyrite in intimate contact with chalcopyrite increases the formation of surface sulfur species that are implicated in the formation of passivating layers on leached chalcopyrite surfaces. ToF-SIMS analysis of the chalcopyrite and pyrite regions of the heterogeneous sample support the conclusions obtained from the synchrotron surface analysis experiments. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000634 [article] Synchrotron XPS, NEXAFS, and ToF-SIMS studies of solution exposed chalcopyrite and heterogeneous chalcopyrite with pyrite [texte imprimé] / Robert G. Acres, Auteur ; Sarah L. Harmer, Auteur ; David A. Beattie, Auteur . - 2011 . - pp. 928–936. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 928–936 Mots-clés : Sulfide  ores  Leaching  Oxidation Résumé : The surface species present on two pure chalcopyrite samples (one with a smooth fracture surface; one with a rough fracture surface) and one heterogeneous sample containing both chalcopyrite and pyrite have been studied using synchrotron X-ray photoelectron spectroscopy (SXPS), near-edge X-ray Absorption Fluorescence Spectroscopy (NEXAFS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The measurements were performed for samples fractured in N2 and for samples subsequently exposed to pH 1 HCl solution for 2 h. The comparison of freshly fractured and solution exposed mineral surfaces has allowed for the investigation of the role of other mineral phases on the development of chalcopyrite surface species, and the role of chalcopyrite grain size on surface species development. Analysis of the chalcopyrite region of each sample indicates that increased surface roughness and the presence of pyrite in intimate contact with chalcopyrite increases the formation of surface sulfur species that are implicated in the formation of passivating layers on leached chalcopyrite surfaces. ToF-SIMS analysis of the chalcopyrite and pyrite regions of the heterogeneous sample support the conclusions obtained from the synchrotron surface analysis experiments. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000634

Evidence for surface cleaning of sulphide minerals by attritioning in stirred mills / Ye, X. in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 937–944 Titre : Evidence for surface cleaning of sulphide minerals by attritioning in stirred mills Type de document : texte imprimé Auteurs : Ye, X., Auteur ; S. Gredelj, Auteur ; W. Skinner, Auteur Année de publication : 2011 Article en page(s) : pp. 937–944 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Attrition  Stirred  milling  Flotation  Surface  oxidation Résumé : Recent developments in large scale stirred milling technology using ceramic media have allowed its application to relatively coarse particle streams. Apart from benefits in grinding finer more efficiently, benefits may also be derived from the surface cleaning action of stirred mills. This paper discusses evidence for the cleaning action of a stirred mill on the surfaces of chalcocite and effects on its subsequent flotation. Single mineral samples of chalcocite were ground with either stainless or mild steel grinding media. The effects of surface contamination by iron hydroxide on chalcocite floatability were studied using ethylene diamine-tetra acetic acid (EDTA) extraction, X-ray photoelectron spectroscopy (XPS) surface analysis and contact angle measurements. Depression of both coarse (+75 μm) and fine (−10 μm) size fractions was attributed to the surface precipitation of iron hydroxide species. Transfer of iron hydroxides from coarse particles to fine particles was observed with XPS analysis. Recovery of coarse particles (+75 μm) was improved by attritioning, while additional collector was needed to fully restore chalcocite recovery in both fine and coarse size fractions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000646 [article] Evidence for surface cleaning of sulphide minerals by attritioning in stirred mills [texte imprimé] / Ye, X., Auteur ; S. Gredelj, Auteur ; W. Skinner, Auteur . - 2011 . - pp. 937–944. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 937–944 Mots-clés : Attrition  Stirred  milling  Flotation  Surface  oxidation Résumé : Recent developments in large scale stirred milling technology using ceramic media have allowed its application to relatively coarse particle streams. Apart from benefits in grinding finer more efficiently, benefits may also be derived from the surface cleaning action of stirred mills. This paper discusses evidence for the cleaning action of a stirred mill on the surfaces of chalcocite and effects on its subsequent flotation. Single mineral samples of chalcocite were ground with either stainless or mild steel grinding media. The effects of surface contamination by iron hydroxide on chalcocite floatability were studied using ethylene diamine-tetra acetic acid (EDTA) extraction, X-ray photoelectron spectroscopy (XPS) surface analysis and contact angle measurements. Depression of both coarse (+75 μm) and fine (−10 μm) size fractions was attributed to the surface precipitation of iron hydroxide species. Transfer of iron hydroxides from coarse particles to fine particles was observed with XPS analysis. Recovery of coarse particles (+75 μm) was improved by attritioning, while additional collector was needed to fully restore chalcocite recovery in both fine and coarse size fractions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000646

The formulation and use of mixed collectors in sulphide flotation / N.O. Lotter in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 945–951 Titre : The formulation and use of mixed collectors in sulphide flotation Type de document : texte imprimé Auteurs : N.O. Lotter, Auteur ; D. J. Bradshaw, Auteur Année de publication : 2011 Article en page(s) : pp. 945–951 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  Mixed  collectors  Synergy Résumé : Mixtures of collectors have been widely used for many years in sulphide flotation, and a range of performance benefits have been reported for many different systems. The combinations of collector types have varied, as have the ratios that have been used. Synergistic effects have been obtained (greater than the sum of the parts) and in some cases the mechanisms of this improved behaviour have been identified. These benefits have been attributed to increased carrying capacity of the froth phase, faster kinetics, and more successful recovery of middling or coarse particles. It is the interaction between the various components of the mixed collector system, rather than the individual main effects, that dominate the performance benefits. The process benefits include increased paymetal recoveries and grades – as well as increased rates of recovery whilst using lower dosages of reagents. Various mechanisms have been reported and are discussed. These have been shown to affect different composition/liberation classes and sizes of mineral particles. In recent years, automated quantitative mineralogy and surface analysis technology such as ToF-SIMS have enabled the development of better information, to establish what aspect of the process has been affected. This has been successful mostly for use in a diagnostic capacity. Candidate selection for the mixed collector suite is presently based on experience and contextual knowledge. Predictive properties from these systems are a desirable future goal. Currently optimum combinations are preferably identified experimentally at laboratory scale prior to any plant trial. It is recommended that such laboratory work be performed using a factorial design with replicates and quality controls, such as may be delivered from High-Confidence Flotation Testing. The purpose of this paper is to summarise and review current theory and practice in the usage of mixtures of collectors in sulphide flotation – both in the application and in research in order to develop insights and guidelines to develop a methodology for use in a predictive capacity. A case study demonstrating this approach will be published at a later date. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000671 [article] The formulation and use of mixed collectors in sulphide flotation [texte imprimé] / N.O. Lotter, Auteur ; D. J. Bradshaw, Auteur . - 2011 . - pp. 945–951. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 945–951 Mots-clés : Flotation  Mixed  collectors  Synergy Résumé : Mixtures of collectors have been widely used for many years in sulphide flotation, and a range of performance benefits have been reported for many different systems. The combinations of collector types have varied, as have the ratios that have been used. Synergistic effects have been obtained (greater than the sum of the parts) and in some cases the mechanisms of this improved behaviour have been identified. These benefits have been attributed to increased carrying capacity of the froth phase, faster kinetics, and more successful recovery of middling or coarse particles. It is the interaction between the various components of the mixed collector system, rather than the individual main effects, that dominate the performance benefits. The process benefits include increased paymetal recoveries and grades – as well as increased rates of recovery whilst using lower dosages of reagents. Various mechanisms have been reported and are discussed. These have been shown to affect different composition/liberation classes and sizes of mineral particles. In recent years, automated quantitative mineralogy and surface analysis technology such as ToF-SIMS have enabled the development of better information, to establish what aspect of the process has been affected. This has been successful mostly for use in a diagnostic capacity. Candidate selection for the mixed collector suite is presently based on experience and contextual knowledge. Predictive properties from these systems are a desirable future goal. Currently optimum combinations are preferably identified experimentally at laboratory scale prior to any plant trial. It is recommended that such laboratory work be performed using a factorial design with replicates and quality controls, such as may be delivered from High-Confidence Flotation Testing. The purpose of this paper is to summarise and review current theory and practice in the usage of mixtures of collectors in sulphide flotation – both in the application and in research in order to develop insights and guidelines to develop a methodology for use in a predictive capacity. A case study demonstrating this approach will be published at a later date. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000671

A vibrational spectroscopy and XPS investigation of the interaction of hydroxamate reagents on copper oxide minerals / G.A. Hope in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 952–959 Titre : A vibrational spectroscopy and XPS investigation of the interaction of hydroxamate reagents on copper oxide minerals Type de document : texte imprimé Auteurs : G.A. Hope, Auteur ; R. Woods, Auteur ; G.K. Parker, Auteur Année de publication : 2011 Article en page(s) : pp. 952–959 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Alkyl  hydroxamates  Mineral  processing  Flotation  collectors  Oxide  ores Résumé : Vibrational spectroscopy and X-ray photoelectron spectroscopy (XPS) studies have been carried out to investigate the interaction of n-octanohydroxamic acid, acetohydroxamic acid and potassium hydrogen n-octanohydroxamate with a copper electrode, malachite and cuprite. Bulk analysis, XPS, Raman and FT-IR have been used to characterise the reactants, surface products and the bulk copper compounds. Copper aceto- and n-octanohydroxamates have been shown to have a 1:1 stoichiometry. XPS results for cuprite and malachite minerals show the formation of a layer of copper n-octanohydroxamate under the conditions investigated. Surface enhanced Raman scattering (SERS) studies at gold coated malachite mineral surfaces have been attempted with acetohydroxamic acid, the acid potassium salt of n-octanohydroxamic acid and the commercial collector AM28. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000683 [article] A vibrational spectroscopy and XPS investigation of the interaction of hydroxamate reagents on copper oxide minerals [texte imprimé] / G.A. Hope, Auteur ; R. Woods, Auteur ; G.K. Parker, Auteur . - 2011 . - pp. 952–959. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 952–959 Mots-clés : Alkyl  hydroxamates  Mineral  processing  Flotation  collectors  Oxide  ores Résumé : Vibrational spectroscopy and X-ray photoelectron spectroscopy (XPS) studies have been carried out to investigate the interaction of n-octanohydroxamic acid, acetohydroxamic acid and potassium hydrogen n-octanohydroxamate with a copper electrode, malachite and cuprite. Bulk analysis, XPS, Raman and FT-IR have been used to characterise the reactants, surface products and the bulk copper compounds. Copper aceto- and n-octanohydroxamates have been shown to have a 1:1 stoichiometry. XPS results for cuprite and malachite minerals show the formation of a layer of copper n-octanohydroxamate under the conditions investigated. Surface enhanced Raman scattering (SERS) studies at gold coated malachite mineral surfaces have been attempted with acetohydroxamic acid, the acid potassium salt of n-octanohydroxamic acid and the commercial collector AM28. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000683

Understanding gamsberg / R. Schouwstra in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 960–967 Titre : Understanding gamsberg : A geometallurgical study of a large stratiform zinc deposit Type de document : texte imprimé Auteurs : R. Schouwstra, Auteur ; D. De Vaux, Auteur ; P. Hey, Auteur Année de publication : 2011 Article en page(s) : pp. 960–967 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulphide  ores  Froth  flotation  Ore  mineralogy  Liberation Résumé : The Gamsberg zinc deposit in the Northern Cape in South Africa has been the subject of a number of studies by Anglo American over the years. Two distinct ore types have been identified, namely pelitic and garnet-magnetite ore. The ore is characterised by relatively high manganese levels. Manganese reporting to the flotation concentrate is problematic for downstream refining. Anglo Research was asked by the exploration division of Anglo Base to study the relationship between the mineralogy and the floatability of the ore from reef intersections obtained from the eastern ore body. The two ore types were found to have different mineralogical characteristics resulting in different flotation responses both in terms of zinc and manganese recoveries and concentrate grades. The presence of the manganese sulphide, alabandite, was also established, and was found to be extremely detrimental to sphalerite flotation. The reasons for this were explained using the surface analysis facility at Anglo Research. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000695 [article] Understanding gamsberg : A geometallurgical study of a large stratiform zinc deposit [texte imprimé] / R. Schouwstra, Auteur ; D. De Vaux, Auteur ; P. Hey, Auteur . - 2011 . - pp. 960–967. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 960–967 Mots-clés : Sulphide  ores  Froth  flotation  Ore  mineralogy  Liberation Résumé : The Gamsberg zinc deposit in the Northern Cape in South Africa has been the subject of a number of studies by Anglo American over the years. Two distinct ore types have been identified, namely pelitic and garnet-magnetite ore. The ore is characterised by relatively high manganese levels. Manganese reporting to the flotation concentrate is problematic for downstream refining. Anglo Research was asked by the exploration division of Anglo Base to study the relationship between the mineralogy and the floatability of the ore from reef intersections obtained from the eastern ore body. The two ore types were found to have different mineralogical characteristics resulting in different flotation responses both in terms of zinc and manganese recoveries and concentrate grades. The presence of the manganese sulphide, alabandite, was also established, and was found to be extremely detrimental to sphalerite flotation. The reasons for this were explained using the surface analysis facility at Anglo Research. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000695

The development of a cavern model for mechanical flotation cells / C. W. Bakker in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 968–972 Titre : The development of a cavern model for mechanical flotation cells Type de document : texte imprimé Auteurs : C. W. Bakker, Auteur ; C.J. Meyer, Auteur ; D.A. Deglon, Auteur Année de publication : 2011 Article en page(s) : pp. 968–972 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Modelling  Computational  fluid  dynamics  Froth  flotation  Fine  particle  processing  Agitation Résumé : Certain fine particle and high solid concentration mineral slurries used in the froth flotation process have been shown to exhibit non-Newtonian rheologies, including a yield stress. The mixing characteristics of these fluids are often problematic as a cavern of yielded fluid forms around the impeller whilst the rest of the fluid remains stagnant and therefore unmixed. This paper aims to develop a semi-empirical model to calculate the height of caverns forming in non-Newtonian mineral slurries in a mechanical flotation cell. Cavern shapes in a pilot-scale Batequip flotation cell were numerically determined for a range of mineral slurries using an experimentally validated Computational Fluid Dynamics (CFD) model. Development of the cavern height model was based on the assumption that the cavern boundary was formed where the shear stress imposed on the slurry equaled the fluid yield stress and also that the flow along the cell walls could be represented by an annular wall jet. It was found that the cavern height was directly proportional to the product of the slurry density and the square of the impeller tip speed, and inversely proportional to the slurry yield stress. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000725 [article] The development of a cavern model for mechanical flotation cells [texte imprimé] / C. W. Bakker, Auteur ; C.J. Meyer, Auteur ; D.A. Deglon, Auteur . - 2011 . - pp. 968–972. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 968–972 Mots-clés : Modelling  Computational  fluid  dynamics  Froth  flotation  Fine  particle  processing  Agitation Résumé : Certain fine particle and high solid concentration mineral slurries used in the froth flotation process have been shown to exhibit non-Newtonian rheologies, including a yield stress. The mixing characteristics of these fluids are often problematic as a cavern of yielded fluid forms around the impeller whilst the rest of the fluid remains stagnant and therefore unmixed. This paper aims to develop a semi-empirical model to calculate the height of caverns forming in non-Newtonian mineral slurries in a mechanical flotation cell. Cavern shapes in a pilot-scale Batequip flotation cell were numerically determined for a range of mineral slurries using an experimentally validated Computational Fluid Dynamics (CFD) model. Development of the cavern height model was based on the assumption that the cavern boundary was formed where the shear stress imposed on the slurry equaled the fluid yield stress and also that the flow along the cell walls could be represented by an annular wall jet. It was found that the cavern height was directly proportional to the product of the slurry density and the square of the impeller tip speed, and inversely proportional to the slurry yield stress. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000725

Modelling bubble–particle interaction with dynamic surface tension / Gijsbert Wierink in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 973–978 Titre : Modelling bubble–particle interaction with dynamic surface tension Type de document : texte imprimé Auteurs : Gijsbert Wierink, Auteur ; Kari Heiskanen, Auteur Année de publication : 2011 Article en page(s) : pp. 973–978 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  bubbles  Modelling Résumé : Bubble–particle interaction in turbulent flow is a dynamic process by its very nature. Important flotation parameters such as air hold-up, bubble size distribution, and bubble–particle interaction are strongly influenced by the shape and behavior of bubbles in turbulent flow. Bubble dynamics and the behavior of the three-phase interface are determined by the local surface tension and surfactant mass transfer characteristics. For systems with homogeneous distribution of surfactants the Marangoni term vanishes from the balance of bubble surface forces. In flotation however the heterogeneity of spatial and temporal distribution of surfactants requires reformulation of the interfacial stress balance and inclusion of the Marangoni effect. In this paper we propose a method for dynamic modeling of surface tension forces in flotation systems. The understanding of bubble and surfactant dynamics can contribute to greater insight in the physico-chemical behavior of flotation systems. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000890 [article] Modelling bubble–particle interaction with dynamic surface tension [texte imprimé] / Gijsbert Wierink, Auteur ; Kari Heiskanen, Auteur . - 2011 . - pp. 973–978. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 973–978 Mots-clés : Froth  flotation  Flotation  bubbles  Modelling Résumé : Bubble–particle interaction in turbulent flow is a dynamic process by its very nature. Important flotation parameters such as air hold-up, bubble size distribution, and bubble–particle interaction are strongly influenced by the shape and behavior of bubbles in turbulent flow. Bubble dynamics and the behavior of the three-phase interface are determined by the local surface tension and surfactant mass transfer characteristics. For systems with homogeneous distribution of surfactants the Marangoni term vanishes from the balance of bubble surface forces. In flotation however the heterogeneity of spatial and temporal distribution of surfactants requires reformulation of the interfacial stress balance and inclusion of the Marangoni effect. In this paper we propose a method for dynamic modeling of surface tension forces in flotation systems. The understanding of bubble and surfactant dynamics can contribute to greater insight in the physico-chemical behavior of flotation systems. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000890

The effects of hydrophobicity and orientation of cubic particles on the stability of thin films / G. Morris in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 979–984 Titre : The effects of hydrophobicity and orientation of cubic particles on the stability of thin films Type de document : texte imprimé Auteurs : G. Morris, Auteur ; S.J. Neethling, Auteur ; J. J. Cilliers, Auteur Année de publication : 2011 Article en page(s) : pp. 979–984 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  froths  Froth  flotation  Modelling  Simulation Résumé : A three-dimensional model of a single cubic particle in a thin liquid film has been developed using the Surface Evolver (Brakke, 1992) program. It has been used to investigate the effect of a particle’s contact angle on its energetically stable orientations at a liquid–vapour interface and how these, in turn, affect the particle’s ability to stabilise a thin film. It has been found that depending on the contact angle there are two possible stable orientations for a cubic particle (termed horizontal and rotated) at a liquid–vapour interface. For a film containing a cubic particle in a rotated orientation it has been found that the capillary pressure required to rupture the film is roughly 30% of that required for a film containing a particle of the same contact angle but in a horizontal orientation. The probability of a particle adopting one orientation over another is also investigated, showing that this too is affected by contact angle and leading to the conclusion that contact angle has a profound effect on non-spherical particles behaviour in thin films. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000956 [article] The effects of hydrophobicity and orientation of cubic particles on the stability of thin films [texte imprimé] / G. Morris, Auteur ; S.J. Neethling, Auteur ; J. J. Cilliers, Auteur . - 2011 . - pp. 979–984. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 979–984 Mots-clés : Flotation  froths  Froth  flotation  Modelling  Simulation Résumé : A three-dimensional model of a single cubic particle in a thin liquid film has been developed using the Surface Evolver (Brakke, 1992) program. It has been used to investigate the effect of a particle’s contact angle on its energetically stable orientations at a liquid–vapour interface and how these, in turn, affect the particle’s ability to stabilise a thin film. It has been found that depending on the contact angle there are two possible stable orientations for a cubic particle (termed horizontal and rotated) at a liquid–vapour interface. For a film containing a cubic particle in a rotated orientation it has been found that the capillary pressure required to rupture the film is roughly 30% of that required for a film containing a particle of the same contact angle but in a horizontal orientation. The probability of a particle adopting one orientation over another is also investigated, showing that this too is affected by contact angle and leading to the conclusion that contact angle has a profound effect on non-spherical particles behaviour in thin films. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000956

Adsorption of tailored carboxymethyl cellulose polymers on talc and chalcopyrite / Agnieszka Mierczynska-Vasilev in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 985–993 Titre : Adsorption of tailored carboxymethyl cellulose polymers on talc and chalcopyrite : Correlation between coverage, wettability, and flotation Type de document : texte imprimé Auteurs : Agnieszka Mierczynska-Vasilev, Auteur ; David A. Beattie, Auteur Année de publication : 2011 Article en page(s) : pp. 985–993 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  depressants  Sulfide  ores  Surface  modification Résumé : A carefully chosen selection of CMC polymers was used to probe the depression of talc and chalcopyrite and to highlight the effect of specific alterations of the bulk polymer chemistry on the power and selectivity of the depressants. In situ tapping mode atomic force microscopy (AFM), captive bubble contact angle measurements, and flotation tests were used to study the adsorption of the CMC polymers on chalcopyrite and talc. The degree of substitution and distribution of substitution of carboxymethyl groups on CMC was seen to have a strong influence on the ability of the polymers to adsorb onto the surface of talc and chalcopyrite. High substitution results in low coverage on both minerals whereas low substitution results in higher coverage. The influence of distribution of substitution (random or clustered) was also seen to affect the adsorption, with more random/even substitution giving rise to greater adsorption on talc and chalcopyrite. The contact angle of talc and chalcopyrite is significantly altered in the presence of the three polymers, with increased surface coverage (determined by AFM) correlating with the ability of the polymers to decrease the wettability of talc and chalcopyrite. This trend was also followed in single and mixed mineral talc and chalcopyrite flotation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000968 [article] Adsorption of tailored carboxymethyl cellulose polymers on talc and chalcopyrite : Correlation between coverage, wettability, and flotation [texte imprimé] / Agnieszka Mierczynska-Vasilev, Auteur ; David A. Beattie, Auteur . - 2011 . - pp. 985–993. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 985–993 Mots-clés : Flotation  depressants  Sulfide  ores  Surface  modification Résumé : A carefully chosen selection of CMC polymers was used to probe the depression of talc and chalcopyrite and to highlight the effect of specific alterations of the bulk polymer chemistry on the power and selectivity of the depressants. In situ tapping mode atomic force microscopy (AFM), captive bubble contact angle measurements, and flotation tests were used to study the adsorption of the CMC polymers on chalcopyrite and talc. The degree of substitution and distribution of substitution of carboxymethyl groups on CMC was seen to have a strong influence on the ability of the polymers to adsorb onto the surface of talc and chalcopyrite. High substitution results in low coverage on both minerals whereas low substitution results in higher coverage. The influence of distribution of substitution (random or clustered) was also seen to affect the adsorption, with more random/even substitution giving rise to greater adsorption on talc and chalcopyrite. The contact angle of talc and chalcopyrite is significantly altered in the presence of the three polymers, with increased surface coverage (determined by AFM) correlating with the ability of the polymers to decrease the wettability of talc and chalcopyrite. This trend was also followed in single and mixed mineral talc and chalcopyrite flotation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000968

Recovery vs. mass pull / K. Hadler in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 994–1002 Titre : Recovery vs. mass pull : The link to air recovery Type de document : texte imprimé Auteurs : K. Hadler, Auteur ; C.D. Smith, Auteur ; J. J. Cilliers, Auteur Année de publication : 2011 Article en page(s) : pp. 994–1002 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  froths  Froth  flotation  Flotation  bubbles  Process  optimisation Résumé : In recent years, developments in control strategy for banks of flotation cells have included process control based on mass pull. Mass pull, or the flowrate of solids reporting to the concentrate, is affected by changes in froth structure and stability which are in turn affected by changes in operating parameters such as air flowrate and froth depth. Air recovery, or the fraction of air entering a cell that overflows the lip as unburst bubbles, is a robust, non-intrusive measure of froth stability that passes through a peak as cell air rate is increased. Furthermore, it has been shown that when operating a cell at the air rate that yields the ‘Peak Air Recovery’ (PAR), an improvement in flotation performance, particularly mineral recovery, can be obtained. In this paper, results from industrial experiments are reported that compare the effect of air rate on air recovery and flotation performance, and specifically the effect on mass pull and mineral recovery. The results show that an increase in mass pull does not necessarily yield an increased mineral recovery in all cases, since it is dependent on whether the air rate must be increased or decreased to obtain the ‘Peak Air Recovery’. This work shows the potential gain to be made from control using air recovery measurements and operating at PAR conditions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001159 [article] Recovery vs. mass pull : The link to air recovery [texte imprimé] / K. Hadler, Auteur ; C.D. Smith, Auteur ; J. J. Cilliers, Auteur . - 2011 . - pp. 994–1002. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 994–1002 Mots-clés : Flotation  froths  Froth  flotation  Flotation  bubbles  Process  optimisation Résumé : In recent years, developments in control strategy for banks of flotation cells have included process control based on mass pull. Mass pull, or the flowrate of solids reporting to the concentrate, is affected by changes in froth structure and stability which are in turn affected by changes in operating parameters such as air flowrate and froth depth. Air recovery, or the fraction of air entering a cell that overflows the lip as unburst bubbles, is a robust, non-intrusive measure of froth stability that passes through a peak as cell air rate is increased. Furthermore, it has been shown that when operating a cell at the air rate that yields the ‘Peak Air Recovery’ (PAR), an improvement in flotation performance, particularly mineral recovery, can be obtained. In this paper, results from industrial experiments are reported that compare the effect of air rate on air recovery and flotation performance, and specifically the effect on mass pull and mineral recovery. The results show that an increase in mass pull does not necessarily yield an increased mineral recovery in all cases, since it is dependent on whether the air rate must be increased or decreased to obtain the ‘Peak Air Recovery’. This work shows the potential gain to be made from control using air recovery measurements and operating at PAR conditions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001159

Impact of talc on pulp and froth properties in F150 and 1-pentanol frother systems / Seng How Kuan in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1003–1009 Titre : Impact of talc on pulp and froth properties in F150 and 1-pentanol frother systems Type de document : texte imprimé Auteurs : Seng How Kuan, Auteur ; James A. Finch, Auteur Année de publication : 2011 Article en page(s) : pp. 1003–1009 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  bubbles  Flotation  frothers  Flotation  froths Résumé : The role of frother controlling bubble size and froth properties is reasonably well understood in the air–water system. A concern is how well this relates to the three-phase flotation condition. As a model hydrophobic solid talc was used. A column was run at fixed froth depth and air rate with overflow and underflow recycled. Four frothers were examined, two polyglycols, polypropylene glycol (F150), polypropylene methyl ether (DF250), and two alcohols, 1-heptanol and 1-pentanol. At steady state, pulp zone gas holdup and bubble size were measured along with water and solids overflow rate as a function of talc addition. For 1-heptanol and DF250 there was no impact of talc on bubble size or gas holdup. For 1-pentanol the presence of talc had no effect on bubble size but gas holdup increased; in contrast, for F150 addition of talc increased bubble size and decreased gas holdup. There was a reversal in water overflow rate between the F150 and 1-pentanol on adding talc, the 5:1 ratio in favour of F150 in air–water becoming 3:1 in favour of 1-pentanol at 5 wt% talc. The solids overflow rate likewise favoured 1-pentanol in presence of talc. The increase in bubble size in the talc/F150 system implies coalescence, as further evidenced by the bubble size distribution becoming bi-modal. The mechanism proposed was a combination of talc adsorbing frother from solution, demonstrated by TOC analysis of residual frother, and directly from the bubble surface due to the orientation of adsorbed F150. In the talc/pentanol case the increase in gas holdup was attributed to bubbles not being at terminal velocity and attached talc particles increasing deceleration, i.e., slowing bubble rise. The increase in water overflow rate in the talc/pentanol system corresponds to increased froth stability imparted by hydrophobic solids. Froth stabilization by talc with F150, however, is offset by the increased bubble size that means less water is carried into the froth. The reversal in water overflow ranking of the frothers can, therefore, be interpreted as due to frother/solid interactions. Similar interactions may account for reversals noted in other systems. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001184 [article] Impact of talc on pulp and froth properties in F150 and 1-pentanol frother systems [texte imprimé] / Seng How Kuan, Auteur ; James A. Finch, Auteur . - 2011 . - pp. 1003–1009. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1003–1009 Mots-clés : Flotation  bubbles  Flotation  frothers  Flotation  froths Résumé : The role of frother controlling bubble size and froth properties is reasonably well understood in the air–water system. A concern is how well this relates to the three-phase flotation condition. As a model hydrophobic solid talc was used. A column was run at fixed froth depth and air rate with overflow and underflow recycled. Four frothers were examined, two polyglycols, polypropylene glycol (F150), polypropylene methyl ether (DF250), and two alcohols, 1-heptanol and 1-pentanol. At steady state, pulp zone gas holdup and bubble size were measured along with water and solids overflow rate as a function of talc addition. For 1-heptanol and DF250 there was no impact of talc on bubble size or gas holdup. For 1-pentanol the presence of talc had no effect on bubble size but gas holdup increased; in contrast, for F150 addition of talc increased bubble size and decreased gas holdup. There was a reversal in water overflow rate between the F150 and 1-pentanol on adding talc, the 5:1 ratio in favour of F150 in air–water becoming 3:1 in favour of 1-pentanol at 5 wt% talc. The solids overflow rate likewise favoured 1-pentanol in presence of talc. The increase in bubble size in the talc/F150 system implies coalescence, as further evidenced by the bubble size distribution becoming bi-modal. The mechanism proposed was a combination of talc adsorbing frother from solution, demonstrated by TOC analysis of residual frother, and directly from the bubble surface due to the orientation of adsorbed F150. In the talc/pentanol case the increase in gas holdup was attributed to bubbles not being at terminal velocity and attached talc particles increasing deceleration, i.e., slowing bubble rise. The increase in water overflow rate in the talc/pentanol system corresponds to increased froth stability imparted by hydrophobic solids. Froth stabilization by talc with F150, however, is offset by the increased bubble size that means less water is carried into the froth. The reversal in water overflow ranking of the frothers can, therefore, be interpreted as due to frother/solid interactions. Similar interactions may account for reversals noted in other systems. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001184

The effect of increased frother dosage on froth stability at high depressant dosages / J.G. Wiese in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1010–1017 Titre : The effect of increased frother dosage on froth stability at high depressant dosages Type de document : texte imprimé Auteurs : J.G. Wiese, Auteur ; P.J. Harris, Auteur ; D. J. Bradshaw, Auteur Année de publication : 2011 Article en page(s) : pp. 1010–1017 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Precious  metal  ores  Froth  flotation  Flotation  depressants  Flotation  frothers Résumé : High energy costs required to smelt low grade concentrates could be alleviated by the production of high grade concentrates. Obtaining maximum PGM recovery by the use of high dosages of polysaccharide depressants may be problematic in that a significant decrease in the stability of the froth, particularly with CMC, results. These highly unstable froths may result in restricted mass pulls and decreased valuable mineral recovery. There are a number of ways of counteracting unstable froths, such as increasing airflow rate, reducing froth height or increasing frother dosage. Although necessary to maximise PGM recovery, all of these are likely to lead to increased water recovery and dilution of the concentrate by entrained material. This work examines the effect of increasing frother dosage on the recovery of sulphide minerals and floatable gangue from a Merensky ore at varying dosages of guar gum and CMC, as well as on the recovery of entrained gangue and its dependence on the physical nature of the flotation pulp. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001196 [article] The effect of increased frother dosage on froth stability at high depressant dosages [texte imprimé] / J.G. Wiese, Auteur ; P.J. Harris, Auteur ; D. J. Bradshaw, Auteur . - 2011 . - pp. 1010–1017. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1010–1017 Mots-clés : Precious  metal  ores  Froth  flotation  Flotation  depressants  Flotation  frothers Résumé : High energy costs required to smelt low grade concentrates could be alleviated by the production of high grade concentrates. Obtaining maximum PGM recovery by the use of high dosages of polysaccharide depressants may be problematic in that a significant decrease in the stability of the froth, particularly with CMC, results. These highly unstable froths may result in restricted mass pulls and decreased valuable mineral recovery. There are a number of ways of counteracting unstable froths, such as increasing airflow rate, reducing froth height or increasing frother dosage. Although necessary to maximise PGM recovery, all of these are likely to lead to increased water recovery and dilution of the concentrate by entrained material. This work examines the effect of increasing frother dosage on the recovery of sulphide minerals and floatable gangue from a Merensky ore at varying dosages of guar gum and CMC, as well as on the recovery of entrained gangue and its dependence on the physical nature of the flotation pulp. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001196

Froth touch samples viewed with scanning electron microscopy / K.E. Cole in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1018–1022 Titre : Froth touch samples viewed with scanning electron microscopy Type de document : texte imprimé Auteurs : K.E. Cole, Auteur ; G.D.M. Morris, Auteur ; J. J. Cilliers, Auteur Année de publication : 2011 Article en page(s) : pp. 1018–1022 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  froths  Modelling  Particle  size  Sampling Résumé : The stability of the thin films found in the froth phase of flotation plays an important role in the overall efficiency of the separation process. In turn, the physical behaviour of the particles attached to the films has a direct impact on the lamella stability. This effect is not fully understood. The film solids loading, or attached mass to area ratio, is an indicator of froth stability and has been measured by touch sampling of surface bubbles. Multiple samples can also be assayed as an indicator of maximum possible grade. Here the touch sample technique is used to show the particle packing arrangement on the film. This work presents images of touch samples from the top of the froth viewed under a Scanning Electron Microscope (SEM). Froth samples were obtained during batch flotation of glass beads with a size fraction of 90–150 μm. The packing arrangement of the particles attached to the surface lamellae were clearly resolved, making it possible to obtain a measure of film packing density using image analysis. These results can be used to validate and expand physical models that predict film stability. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001238 [article] Froth touch samples viewed with scanning electron microscopy [texte imprimé] / K.E. Cole, Auteur ; G.D.M. Morris, Auteur ; J. J. Cilliers, Auteur . - 2011 . - pp. 1018–1022. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1018–1022 Mots-clés : Flotation  froths  Modelling  Particle  size  Sampling Résumé : The stability of the thin films found in the froth phase of flotation plays an important role in the overall efficiency of the separation process. In turn, the physical behaviour of the particles attached to the films has a direct impact on the lamella stability. This effect is not fully understood. The film solids loading, or attached mass to area ratio, is an indicator of froth stability and has been measured by touch sampling of surface bubbles. Multiple samples can also be assayed as an indicator of maximum possible grade. Here the touch sample technique is used to show the particle packing arrangement on the film. This work presents images of touch samples from the top of the froth viewed under a Scanning Electron Microscope (SEM). Froth samples were obtained during batch flotation of glass beads with a size fraction of 90–150 μm. The packing arrangement of the particles attached to the surface lamellae were clearly resolved, making it possible to obtain a measure of film packing density using image analysis. These results can be used to validate and expand physical models that predict film stability. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001238

Flotation bank air addition and distribution for optimal performance / C.D. Smith in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1023–1029 Titre : Flotation bank air addition and distribution for optimal performance Type de document : texte imprimé Auteurs : C.D. Smith, Auteur ; K. Hadler, Auteur ; J. J. Cilliers, Auteur Année de publication : 2011 Article en page(s) : pp. 1023–1029 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Mineral  processing  Froth  flotation  Air  profiling  Air  recovery  Optimisation Résumé : Recent studies have shown that varying the distribution of a set volume of air to a flotation bank significantly affects the performance of the bank. To date, however, the volume of air to be distributed has usually been arbitrarily set as that added with the ‘as found’ air rates, the typical operating air rates; not necessarily an optimum. Studies examining the effect of different total air additions, at a constant distribution, have shown the addition maximising air recovery typically yields the best performance. Air recovery is the fraction of the air added to a cell which overflows the lip of the cell as unburst bubbles and shows a peak with respect to cell aeration. In this work three experimental case studies are presented to examine of the role of aeration in flotation performance, with the aim of developing a generic technique to determine both the required total air addition and distribution of air to a bank of flotation cells. The first case study compares performance at three different total air additions. The air addition which gave the Peak Air Recovery (PAR) also gave the highest mineral recovery. Thus air recovery optimisation yields the optimum total air addition to a flotation bank. In the second case study the air recovery was optimised from each cell in a bank individually. The PAR air addition once more gave the highest mineral recovery from the bank. Therefore, air recovery optimisation determines the optimum total air addition to a bank and also provides a distribution for that air. The third case study compares a profile based on the PAR air rates with other distributions of the same total air. The results show the profile based on the PAR air rates gave a significantly higher cumulative mineral recovery than other distributions of the same volume of air, for the same cumulative grade. The results of the three case studies show air recovery optimisation of each cell in a bank is a robust and generic technique to simultaneously determine the optimum bank aeration and the optimum distribution of this air within the bank. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000124X [article] Flotation bank air addition and distribution for optimal performance [texte imprimé] / C.D. Smith, Auteur ; K. Hadler, Auteur ; J. J. Cilliers, Auteur . - 2011 . - pp. 1023–1029. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1023–1029 Mots-clés : Mineral  processing  Froth  flotation  Air  profiling  Air  recovery  Optimisation Résumé : Recent studies have shown that varying the distribution of a set volume of air to a flotation bank significantly affects the performance of the bank. To date, however, the volume of air to be distributed has usually been arbitrarily set as that added with the ‘as found’ air rates, the typical operating air rates; not necessarily an optimum. Studies examining the effect of different total air additions, at a constant distribution, have shown the addition maximising air recovery typically yields the best performance. Air recovery is the fraction of the air added to a cell which overflows the lip of the cell as unburst bubbles and shows a peak with respect to cell aeration. In this work three experimental case studies are presented to examine of the role of aeration in flotation performance, with the aim of developing a generic technique to determine both the required total air addition and distribution of air to a bank of flotation cells. The first case study compares performance at three different total air additions. The air addition which gave the Peak Air Recovery (PAR) also gave the highest mineral recovery. Thus air recovery optimisation yields the optimum total air addition to a flotation bank. In the second case study the air recovery was optimised from each cell in a bank individually. The PAR air addition once more gave the highest mineral recovery from the bank. Therefore, air recovery optimisation determines the optimum total air addition to a bank and also provides a distribution for that air. The third case study compares a profile based on the PAR air rates with other distributions of the same total air. The results show the profile based on the PAR air rates gave a significantly higher cumulative mineral recovery than other distributions of the same volume of air, for the same cumulative grade. The results of the three case studies show air recovery optimisation of each cell in a bank is a robust and generic technique to simultaneously determine the optimum bank aeration and the optimum distribution of this air within the bank. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000124X

Flotation rate distribution in the collection zone of industrial cells / J. Yianatos in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1030–1035 Titre : Flotation rate distribution in the collection zone of industrial cells Type de document : texte imprimé Auteurs : J. Yianatos, Auteur ; L. Bergh, Auteur ; L. Vinnett, Auteur Année de publication : 2011 Article en page(s) : pp. 1030–1035 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  Flotation  rate  distribution  Industrial  cells  Radioactive  tracer Résumé : The batch flotation process has been commonly characterized assuming a flotation rate distribution function F(k), e.g.: Dirac delta, Rectangular, Gamma or Weibull functions. The identification of F(k) for the collection zone of continuous industrial cells is more complex and to the authors knowledge, has not been reported yet. In this work, a novel procedure to estimate the flotation rate distribution from the collection zone of industrial flotation cells, using the radioactive tracer technique, is presented. The approach consists of measuring the impulse response of the floatable mineral tracer concentration, and non-floatable gangue tracer concentration (Residence Time Distribution, RTD), in the cell tailings. Then, the floatable tracer concentration can be compared with the model prediction, using the Gamma function and the RTD of the non-floatable tracer. Thus, the F(k) distribution parameters were obtained by means of the least-square estimation. The new approach was successfully tested in industrial rougher flotation cells of large size. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000141X [article] Flotation rate distribution in the collection zone of industrial cells [texte imprimé] / J. Yianatos, Auteur ; L. Bergh, Auteur ; L. Vinnett, Auteur . - 2011 . - pp. 1030–1035. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1030–1035 Mots-clés : Flotation  Flotation  rate  distribution  Industrial  cells  Radioactive  tracer Résumé : The batch flotation process has been commonly characterized assuming a flotation rate distribution function F(k), e.g.: Dirac delta, Rectangular, Gamma or Weibull functions. The identification of F(k) for the collection zone of continuous industrial cells is more complex and to the authors knowledge, has not been reported yet. In this work, a novel procedure to estimate the flotation rate distribution from the collection zone of industrial flotation cells, using the radioactive tracer technique, is presented. The approach consists of measuring the impulse response of the floatable mineral tracer concentration, and non-floatable gangue tracer concentration (Residence Time Distribution, RTD), in the cell tailings. Then, the floatable tracer concentration can be compared with the model prediction, using the Gamma function and the RTD of the non-floatable tracer. Thus, the F(k) distribution parameters were obtained by means of the least-square estimation. The new approach was successfully tested in industrial rougher flotation cells of large size. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000141X

Combining Positron Emission Particle Tracking and image analysis to interpret particle motion in froths / K.E. Cole in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1036–1044 Titre : Combining Positron Emission Particle Tracking and image analysis to interpret particle motion in froths Type de document : texte imprimé Auteurs : K.E. Cole, Auteur ; K.E. Waters, Auteur ; X. Fan, Auteur Année de publication : 2011 Article en page(s) : pp. 1036–1044 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  froths  Flotation  bubbles  Froth  flotation Résumé : Previous research into particle motion in the froth zone has focussed on constructing detailed CFD models that describe the behaviour of particle classes with different properties; density, size and hydrophobicity. These models have been reasonably successful in predicting trends in the separation behaviour and how it can be manipulated. Models of separation sub-processes cannot readily be verified experimentally due to the opacity and fragility of froth systems. Positron Emission Particle Tracking (PEPT) can be applied to particles in froth flotation systems to observe the behaviour of individual particles in a mixed particle–liquid–gas system. However, measuring the particle position alone is not adequate as its behaviour is also affected by instantaneous froth events such as bubble coalescence. To link the observed particle behaviour to the froth behaviour requires multi-modal measurements. Video footage of a rising foam column was recorded simultaneously with PEPT data, so that the PEPT tracer trajectory could be explained in terms of foam structure and events. A time weighting function of cubic splines with kernel width 200 ms was used to remove the effects of signal noise. An ascending 70 μm hydrophilic tracer accelerated within vertical Plateau borders and decelerated in Plateau borders angled away from vertical. The tracer trajectory showed velocity peaks and troughs when it was contained in nodes in a rising foam. When the tracer descended within a foam showing convective roll, coalescence events and subsequent foam deformation directly influenced the tracer trajectory. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001457 [article] Combining Positron Emission Particle Tracking and image analysis to interpret particle motion in froths [texte imprimé] / K.E. Cole, Auteur ; K.E. Waters, Auteur ; X. Fan, Auteur . - 2011 . - pp. 1036–1044. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1036–1044 Mots-clés : Flotation  froths  Flotation  bubbles  Froth  flotation Résumé : Previous research into particle motion in the froth zone has focussed on constructing detailed CFD models that describe the behaviour of particle classes with different properties; density, size and hydrophobicity. These models have been reasonably successful in predicting trends in the separation behaviour and how it can be manipulated. Models of separation sub-processes cannot readily be verified experimentally due to the opacity and fragility of froth systems. Positron Emission Particle Tracking (PEPT) can be applied to particles in froth flotation systems to observe the behaviour of individual particles in a mixed particle–liquid–gas system. However, measuring the particle position alone is not adequate as its behaviour is also affected by instantaneous froth events such as bubble coalescence. To link the observed particle behaviour to the froth behaviour requires multi-modal measurements. Video footage of a rising foam column was recorded simultaneously with PEPT data, so that the PEPT tracer trajectory could be explained in terms of foam structure and events. A time weighting function of cubic splines with kernel width 200 ms was used to remove the effects of signal noise. An ascending 70 μm hydrophilic tracer accelerated within vertical Plateau borders and decelerated in Plateau borders angled away from vertical. The tracer trajectory showed velocity peaks and troughs when it was contained in nodes in a rising foam. When the tracer descended within a foam showing convective roll, coalescence events and subsequent foam deformation directly influenced the tracer trajectory. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001457

The flotation of magnetic and non-magnetic pyrrhotite from selected nickel ore deposits / Megan Becker in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1045–1052 Titre : The flotation of magnetic and non-magnetic pyrrhotite from selected nickel ore deposits Type de document : texte imprimé Auteurs : Megan Becker, Auteur ; Johan De Villiers, Auteur ; Dee Bradshaw, Auteur Année de publication : 2011 Article en page(s) : pp. 1045–1052 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Ore  mineralogy  Sulfide  ores  Oxidation Résumé : The non-stoichiometric sulfide mineral pyrrhotite (Fe(1−x)S), common to many nickel ore deposits, occurs in different crystallographic forms and compositions. A series of pyrrhotite samples derived from Canada, South Africa and Botswana whose mineralogy is well characterised, were selected here in order to develop the relationship between mineralogy and flotation performance. Using both oxygen uptake and microflotation tests, the behaviour of the different pyrrhotite types was compared in terms of the effect of pH and collector addition. Non-magnetic pyrrhotite was less reactive in terms of its oxygen uptake and showed the best collectorless flotation recovery. Magnetic pyrrhotite was more reactive and showed poor collectorless flotation performance that could be improved with the addition of xanthate collector, but only if it was not already passivated. These differences are interpreted to be a result of pyrrhotite mineralogy. This has implications that may aid the manipulation of pyrrhotite flotation performance in processing operations. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001676 [article] The flotation of magnetic and non-magnetic pyrrhotite from selected nickel ore deposits [texte imprimé] / Megan Becker, Auteur ; Johan De Villiers, Auteur ; Dee Bradshaw, Auteur . - 2011 . - pp. 1045–1052. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1045–1052 Mots-clés : Ore  mineralogy  Sulfide  ores  Oxidation Résumé : The non-stoichiometric sulfide mineral pyrrhotite (Fe(1−x)S), common to many nickel ore deposits, occurs in different crystallographic forms and compositions. A series of pyrrhotite samples derived from Canada, South Africa and Botswana whose mineralogy is well characterised, were selected here in order to develop the relationship between mineralogy and flotation performance. Using both oxygen uptake and microflotation tests, the behaviour of the different pyrrhotite types was compared in terms of the effect of pH and collector addition. Non-magnetic pyrrhotite was less reactive in terms of its oxygen uptake and showed the best collectorless flotation recovery. Magnetic pyrrhotite was more reactive and showed poor collectorless flotation performance that could be improved with the addition of xanthate collector, but only if it was not already passivated. These differences are interpreted to be a result of pyrrhotite mineralogy. This has implications that may aid the manipulation of pyrrhotite flotation performance in processing operations. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001676

The effect of using different comminution procedures on the flotation of sphalerite / N.A. Palm in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1053–1057 Titre : The effect of using different comminution procedures on the flotation of sphalerite Type de document : texte imprimé Auteurs : N.A. Palm, Auteur ; N.J. Shackleton, Auteur ; V. Malysiak, Auteur Année de publication : 2011 Article en page(s) : pp. 1053–1057 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulphide  ores  Comminution  Froth  flotation  Liberation Résumé : High Pressure Grinding Rollers (HPGR) are known to reduce energy consumption and wear costs and improve the throughput in the circuit. It has been suggested that they can also modify the liberation characteristics of the ore. In the present study the effect of using conventional crushing as opposed to HPGR in combination with either dry or wet milling was investigated using a base metal sulphide, viz. sphalerite, in order to determine whether there may be an improvement in flotation performance following the use of different comminution procedures. It was found that, irrespective of the crushing procedure (HPGR or conventional), dry milling resulted in the highest grades and recoveries of zinc. These were typically 94% recovery at 40% grade. In order to gain an insight into the effect which these comminution procedures had on the ore, samples of feed and product were investigated using surface analytical techniques. Mineralogical analyses showed no differences in the liberation characteristics of sphalerite irrespective of the comminution procedures used. However, dry milling produced a lower d50. The paper proposes possible reasons to explain these observations. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002001 [article] The effect of using different comminution procedures on the flotation of sphalerite [texte imprimé] / N.A. Palm, Auteur ; N.J. Shackleton, Auteur ; V. Malysiak, Auteur . - 2011 . - pp. 1053–1057. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1053–1057 Mots-clés : Sulphide  ores  Comminution  Froth  flotation  Liberation Résumé : High Pressure Grinding Rollers (HPGR) are known to reduce energy consumption and wear costs and improve the throughput in the circuit. It has been suggested that they can also modify the liberation characteristics of the ore. In the present study the effect of using conventional crushing as opposed to HPGR in combination with either dry or wet milling was investigated using a base metal sulphide, viz. sphalerite, in order to determine whether there may be an improvement in flotation performance following the use of different comminution procedures. It was found that, irrespective of the crushing procedure (HPGR or conventional), dry milling resulted in the highest grades and recoveries of zinc. These were typically 94% recovery at 40% grade. In order to gain an insight into the effect which these comminution procedures had on the ore, samples of feed and product were investigated using surface analytical techniques. Mineralogical analyses showed no differences in the liberation characteristics of sphalerite irrespective of the comminution procedures used. However, dry milling produced a lower d50. The paper proposes possible reasons to explain these observations. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002001

Bubble size measurement in electroflotation / Md. Shahjahan Kaisar Alam Sarkar in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1058–1065 Titre : Bubble size measurement in electroflotation Type de document : texte imprimé Auteurs : Md. Shahjahan Kaisar Alam Sarkar, Auteur ; G.M. Evans, Auteur ; S.W. Donne, Auteur Année de publication : 2011 Article en page(s) : pp. 1058–1065 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Electroflotation  Detached  bubble  diameter  Bubble  generation  rate Résumé : A feature of electroflotation is the ability to create very fine bubbles, which are known to improve flotation performance of fine particles. This study was aimed at determining the hydrogen bubble size generated as a function of current density and electrode geometry. Experiments were performed in a viewing cell that allowed direct visualization of hydrogen bubbles being generated and transported away from platinum wire electrodes of 90, 120 and 190 μm in diameter. The detached bubble diameters varied between 15 and 23 μm in diameter, and for each wire diameter, were little influenced by the applied current in the range 150–350 A/m2. The measurements were consistent with those predicted from a simple force balance analysis based on a H2–Pt–0.2M Na2SO4 contact angle of 0.18°. Interestingly, upon detachment, the bubble size increased rapidly, recording up to an 8-fold increase in volume in the first few millimeters of rise, before approaching the steady state diameter of between 30 and 50 μm in the bulk. This increase in bubble size was found to be mostly due to the transfer of dissolve hydrogen into growing bubble while moving through the electrolyte super saturated by dissolved hydrogen gas. The equilibrium bulk diameter was found to be a function of the rate of hydrogen production, bubble nucleation rate, and dissolved gas concentration field. Consequently, electroflotation cells need to be designed to optimise the contact between the supersaturated liquid and the rising bubble plume. By doing this, the volumetric flux of bubbles will be maximised leading to improved flotation performance. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002141 [article] Bubble size measurement in electroflotation [texte imprimé] / Md. Shahjahan Kaisar Alam Sarkar, Auteur ; G.M. Evans, Auteur ; S.W. Donne, Auteur . - 2011 . - pp. 1058–1065. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1058–1065 Mots-clés : Electroflotation  Detached  bubble  diameter  Bubble  generation  rate Résumé : A feature of electroflotation is the ability to create very fine bubbles, which are known to improve flotation performance of fine particles. This study was aimed at determining the hydrogen bubble size generated as a function of current density and electrode geometry. Experiments were performed in a viewing cell that allowed direct visualization of hydrogen bubbles being generated and transported away from platinum wire electrodes of 90, 120 and 190 μm in diameter. The detached bubble diameters varied between 15 and 23 μm in diameter, and for each wire diameter, were little influenced by the applied current in the range 150–350 A/m2. The measurements were consistent with those predicted from a simple force balance analysis based on a H2–Pt–0.2M Na2SO4 contact angle of 0.18°. Interestingly, upon detachment, the bubble size increased rapidly, recording up to an 8-fold increase in volume in the first few millimeters of rise, before approaching the steady state diameter of between 30 and 50 μm in the bulk. This increase in bubble size was found to be mostly due to the transfer of dissolve hydrogen into growing bubble while moving through the electrolyte super saturated by dissolved hydrogen gas. The equilibrium bulk diameter was found to be a function of the rate of hydrogen production, bubble nucleation rate, and dissolved gas concentration field. Consequently, electroflotation cells need to be designed to optimise the contact between the supersaturated liquid and the rising bubble plume. By doing this, the volumetric flux of bubbles will be maximised leading to improved flotation performance. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510002141

Investigation on alternative depressants for iron ore flotation / H.D.G. Turrer in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1066–1069 Titre : Investigation on alternative depressants for iron ore flotation Type de document : texte imprimé Auteurs : H.D.G. Turrer, Auteur ; A.E.C. Peres, Auteur Année de publication : 2011 Article en page(s) : pp. 1066–1069 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Iron  ores  Flotation  depressants  Flotation  reagents Résumé : Iron ore concentration through flotation represents an important application of reagents in mineral processing. Nowadays all Brazilian iron ore concentrators use starch as iron oxides depressant. This study evaluated the application of other depressants, which are commonly used in other flotation systems. Six carboxymethylcelluloses, three lignosulphonates, one guar gum, and four humic acids samples were investigated in the reverse cationic flotation. Laboratory flotation tests showed that only two polymers (one carboxymethylcellulose and guar gum) reached the same performance as starch. The superior performance of these reagents was due to the presence of the glucopyranose ring. The use of polymers blends led to promising results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001421 [article] Investigation on alternative depressants for iron ore flotation [texte imprimé] / H.D.G. Turrer, Auteur ; A.E.C. Peres, Auteur . - 2011 . - pp. 1066–1069. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1066–1069 Mots-clés : Iron  ores  Flotation  depressants  Flotation  reagents Résumé : Iron ore concentration through flotation represents an important application of reagents in mineral processing. Nowadays all Brazilian iron ore concentrators use starch as iron oxides depressant. This study evaluated the application of other depressants, which are commonly used in other flotation systems. Six carboxymethylcelluloses, three lignosulphonates, one guar gum, and four humic acids samples were investigated in the reverse cationic flotation. Laboratory flotation tests showed that only two polymers (one carboxymethylcellulose and guar gum) reached the same performance as starch. The superior performance of these reagents was due to the presence of the glucopyranose ring. The use of polymers blends led to promising results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001421

Bulk flotation of auriferous pyrite and arsenopyrite by using tertiary dodecyl mercaptan as collector in weak alkaline pulp / Jianhua Chen in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1070–1072 Titre : Bulk flotation of auriferous pyrite and arsenopyrite by using tertiary dodecyl mercaptan as collector in weak alkaline pulp Type de document : texte imprimé Auteurs : Jianhua Chen, Auteur ; Ye Chen, Auteur ; Zongwu Wei, Auteur Année de publication : 2011 Article en page(s) : pp. 1070–1072 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Gold  ores  Flotation  collectors  Froth  flotation  Sulphide  ores Résumé : Laboratory and industrial scale experiments were conducted to investigate the effect of tertiary dodecyl mercaptan (TDM) as a collector on the flotation of auriferous pyrite and arsenopyrite. The optimum recovery of gold associated with auriferous sulphides was obtained by adding a mixture of TDM and sodium butyl xanthate, together with only a little CuSO4 as an activator in a weak alkaline pulp adjusted by NaOH. A two-month industrial trial at the Liumei plant in Guangxi, China showed that an average gold recovery of 90.8% into a concentrate assaying 81.1 g/t Au from a feed assaying 2.9 g/t Au could be achieved at pH 8–8.5 using TDM as a collector. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001755 [article] Bulk flotation of auriferous pyrite and arsenopyrite by using tertiary dodecyl mercaptan as collector in weak alkaline pulp [texte imprimé] / Jianhua Chen, Auteur ; Ye Chen, Auteur ; Zongwu Wei, Auteur . - 2011 . - pp. 1070–1072. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1070–1072 Mots-clés : Gold  ores  Flotation  collectors  Froth  flotation  Sulphide  ores Résumé : Laboratory and industrial scale experiments were conducted to investigate the effect of tertiary dodecyl mercaptan (TDM) as a collector on the flotation of auriferous pyrite and arsenopyrite. The optimum recovery of gold associated with auriferous sulphides was obtained by adding a mixture of TDM and sodium butyl xanthate, together with only a little CuSO4 as an activator in a weak alkaline pulp adjusted by NaOH. A two-month industrial trial at the Liumei plant in Guangxi, China showed that an average gold recovery of 90.8% into a concentrate assaying 81.1 g/t Au from a feed assaying 2.9 g/t Au could be achieved at pH 8–8.5 using TDM as a collector. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001755

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