Dépouillements

Towards zinc metal at McArthur River / Noel A. Warner in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 727–741 Titre : Towards zinc metal at McArthur River Type de document : texte imprimé Auteurs : Noel A. Warner, Auteur Année de publication : 2009 Article en page(s) : pp. 727–741 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Non-ferrous  metallic  ore  Sulphide  ores  Pyrometallurgy  Reaction  kinetics  Extractive  metallurgy Résumé : A conceptual design for producing 300,000 tpa zinc directly from McArthur River bulk concentrates is presented. It takes into account the availability of natural gas and the associated increasing importance of Darwin as a hub for natural gas from the Timor Sea. The Albion process for producing zinc at the mine site has been reported as unsuitable because of the costs involved in electricity generation. Clearly, this applies to all hydrometallurgical processes employing electrowinning. What is needed is a radical rethink of pyrometallurgical treatment. Emphasis is given to what has become known as the “Warner process”, modified to yield considerable savings in energy requirements by removing the need for an air separation and massively increasing the intensity throughout. Particular attention is given to the condensation of zinc without fog formation, followed by in-line refining to SHG. The principal reactor involved is identical in size and vacuum pumping system to the Port Talbot (UK) recirculating degasser for producing ultra low carbon steel. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508002707 [article] Towards zinc metal at McArthur River [texte imprimé] / Noel A. Warner, Auteur . - 2009 . - pp. 727–741. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 727–741 Mots-clés : Non-ferrous  metallic  ore  Sulphide  ores  Pyrometallurgy  Reaction  kinetics  Extractive  metallurgy Résumé : A conceptual design for producing 300,000 tpa zinc directly from McArthur River bulk concentrates is presented. It takes into account the availability of natural gas and the associated increasing importance of Darwin as a hub for natural gas from the Timor Sea. The Albion process for producing zinc at the mine site has been reported as unsuitable because of the costs involved in electricity generation. Clearly, this applies to all hydrometallurgical processes employing electrowinning. What is needed is a radical rethink of pyrometallurgical treatment. Emphasis is given to what has become known as the “Warner process”, modified to yield considerable savings in energy requirements by removing the need for an air separation and massively increasing the intensity throughout. Particular attention is given to the condensation of zinc without fog formation, followed by in-line refining to SHG. The principal reactor involved is identical in size and vacuum pumping system to the Port Talbot (UK) recirculating degasser for producing ultra low carbon steel. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508002707

Top submerged lance direct zinc smelting / J. Hoang in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 742–751 Titre : Top submerged lance direct zinc smelting Type de document : texte imprimé Auteurs : J. Hoang, Auteur ; M.A. Reuter, Auteur ; R. Matusewicz, Auteur Année de publication : 2009 Article en page(s) : pp. 742–751 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Non-ferrous  metallic  ores  Pyrometallurgy  Mineral  processing  Zinc Résumé : A long history of zinc processing starting with pilot plant studies in the 1980s has progressed to the treatment of close to 800,000 tonnes a year of zinc bearing feeds in Top Submerged Lance (TSL) furnaces in the form of residues and slags. Whereas these Ausmelt TSL applications are end-of-pipe applications treating residues from classical Roast-Leach-Electrowinning (RLE) process routes, this paper discusses Direct Zinc Smelting (DZS) Process. In Stage 1 of this novel two stage TSL application the sulphide sulphur from the zinc concentrate is the energy carrier used to smelt the concentrate and fume 60–65% of the zinc content. Subsequently in Stage 2 zinc is fumed from the already molten Stage 1 slag to create a final discard slag with a total zinc recovery of 99%. The use of sulphide sulphur as fuel to smelt has economic advantage over the present end-of-pipe TSL applications, that require two steps (for smelting and sulphur removal) and then fuming using primary fuels. The slag product of the DZS process overcomes inherent environmental liability and ever increasing economic burden associated with the traditional RLE processes by eliminating the creation of large volumes of iron bearing residues (mainly jarosite and goethite) while complementing high recoveries of Zn with those of the valuable elements e.g. Cu, Ag, Au, Pb, Ge, and In. High levels of Fe, Mn, SiO2, and MgO in some concentrates render them unsuitable for processing in RLE, however are elegantly directed by DZS to the benign slag. This paper will discuss Ausmelt’s applications in zinc processing with a focus on DZS to show how this process can extend the life of present RLE sites. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508003038 [article] Top submerged lance direct zinc smelting [texte imprimé] / J. Hoang, Auteur ; M.A. Reuter, Auteur ; R. Matusewicz, Auteur . - 2009 . - pp. 742–751. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 742–751 Mots-clés : Non-ferrous  metallic  ores  Pyrometallurgy  Mineral  processing  Zinc Résumé : A long history of zinc processing starting with pilot plant studies in the 1980s has progressed to the treatment of close to 800,000 tonnes a year of zinc bearing feeds in Top Submerged Lance (TSL) furnaces in the form of residues and slags. Whereas these Ausmelt TSL applications are end-of-pipe applications treating residues from classical Roast-Leach-Electrowinning (RLE) process routes, this paper discusses Direct Zinc Smelting (DZS) Process. In Stage 1 of this novel two stage TSL application the sulphide sulphur from the zinc concentrate is the energy carrier used to smelt the concentrate and fume 60–65% of the zinc content. Subsequently in Stage 2 zinc is fumed from the already molten Stage 1 slag to create a final discard slag with a total zinc recovery of 99%. The use of sulphide sulphur as fuel to smelt has economic advantage over the present end-of-pipe TSL applications, that require two steps (for smelting and sulphur removal) and then fuming using primary fuels. The slag product of the DZS process overcomes inherent environmental liability and ever increasing economic burden associated with the traditional RLE processes by eliminating the creation of large volumes of iron bearing residues (mainly jarosite and goethite) while complementing high recoveries of Zn with those of the valuable elements e.g. Cu, Ag, Au, Pb, Ge, and In. High levels of Fe, Mn, SiO2, and MgO in some concentrates render them unsuitable for processing in RLE, however are elegantly directed by DZS to the benign slag. This paper will discuss Ausmelt’s applications in zinc processing with a focus on DZS to show how this process can extend the life of present RLE sites. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508003038

Dispersion effect on a lead–zinc sulphide ore flotation / M.O. Silvestre in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 752–758 Titre : Dispersion effect on a lead–zinc sulphide ore flotation Type de document : texte imprimé Auteurs : M.O. Silvestre, Auteur ; C.A. Pereira, Auteur ; R. Galery, Auteur Année de publication : 2009 Article en page(s) : pp. 752–758 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  reagents  Flotation  depressants Résumé : This investigation was performed with samples from a lead–zinc sulphide deposit aiming at studying the influence of the dispersion degree of the particles in the pulp on lead and zinc flotation. Samples of ore and also of the minerals sphalerite, galena, pyrite, and dolomite were selected for the experiments. Nine types of dispersing agents and six blends among them were employed. A set of three dispersing agents was selected for the lead flotation and another set of three was chosen for zinc flotation. The criteria for the reagents selection were: high dispersion degree for galena and low for the other species, high dispersion degree for sphalerite and low for the other species, low dispersion degree for pyrite and high for the other species, and high dispersion degree for all species. Lead flotation experiments were performed under three conditions aiming at verifying the influence of the dispersing agent, of the pH, and of sodium carbonate. The zinc flotation tests were carried out at pH 10.5, modulated with lime. The use of dispersing agents in lead flotation did not improve the overall efficiency of the circuit for, despite improving the lead metallurgical recovery, they increase significantly the zinc losses in the lead concentrate. Sodium carbonate presented a low dispersion degree and did not affect the lead flotation results when compared with those achieved at natural pH and at pH 9.8 modulated with lime. Two dispersing agents were particularly effective in zinc flotation: dispersant 3223, a sodium polyacrylate, and sodium hexametaphosphate. Both reagents significantly enhanced zinc recovery without impairing the concentrate quality. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508002835 [article] Dispersion effect on a lead–zinc sulphide ore flotation [texte imprimé] / M.O. Silvestre, Auteur ; C.A. Pereira, Auteur ; R. Galery, Auteur . - 2009 . - pp. 752–758. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 752–758 Mots-clés : Froth  flotation  Flotation  reagents  Flotation  depressants Résumé : This investigation was performed with samples from a lead–zinc sulphide deposit aiming at studying the influence of the dispersion degree of the particles in the pulp on lead and zinc flotation. Samples of ore and also of the minerals sphalerite, galena, pyrite, and dolomite were selected for the experiments. Nine types of dispersing agents and six blends among them were employed. A set of three dispersing agents was selected for the lead flotation and another set of three was chosen for zinc flotation. The criteria for the reagents selection were: high dispersion degree for galena and low for the other species, high dispersion degree for sphalerite and low for the other species, low dispersion degree for pyrite and high for the other species, and high dispersion degree for all species. Lead flotation experiments were performed under three conditions aiming at verifying the influence of the dispersing agent, of the pH, and of sodium carbonate. The zinc flotation tests were carried out at pH 10.5, modulated with lime. The use of dispersing agents in lead flotation did not improve the overall efficiency of the circuit for, despite improving the lead metallurgical recovery, they increase significantly the zinc losses in the lead concentrate. Sodium carbonate presented a low dispersion degree and did not affect the lead flotation results when compared with those achieved at natural pH and at pH 9.8 modulated with lime. Two dispersing agents were particularly effective in zinc flotation: dispersant 3223, a sodium polyacrylate, and sodium hexametaphosphate. Both reagents significantly enhanced zinc recovery without impairing the concentrate quality. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508002835

Effect of grinding media on zinc depression in a lead cleaner circuit / J. Kinal in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 759–765 Titre : Effect of grinding media on zinc depression in a lead cleaner circuit Type de document : texte imprimé Auteurs : J. Kinal, Auteur ; C. Greet, Auteur ; I. Goode, Auteur Année de publication : 2009 Article en page(s) : pp. 759–765 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Grinding  Oxidation  Redox  reactions Résumé : Laboratory testwork, investigating the effect of high chrome grinding media in a lead regrind application has on subsequent metallurgical performance, was conducted at a large silver–lead–zinc operation in Australia. The initial data showed that the use of a more inert grinding media could have increased zinc losses to the lead cleaner concentrate if careful attention was not paid to alloy selection. Diagnostic tests showed that iron hydroxide surface coatings generated by grinding media corrosion reactions are an effective depressant for sphalerite in this ore body, even though it is known that an excess of these coatings could depress both galena and sphalerite flotation. These tests demonstrated that a 1% chrome alloy produced the desired pulp chemical conditions to yield an increase in lead concentrate grade through the rejection of sphalerite from the lead circuit. A plant trial was conducted in one of the two parallel grinding/flotation trains, and data collected for statistical analysis. During the plant trial, pulp chemical surveys of the regrind circuit were also taken to compare the effect of grinding media on the cleaner one feed slurry pulp potentials, dissolved oxygen, pH, temperature and EDTA extractable iron. The statistical analysis showed clearly that the change to 1% chrome grinding media had a significant positive impact on improving galena/sphalerite selectivity during lead cleaner flotation and improved the lead concentrate grade. The improved metallurgical performance is explained in terms of modified pulp chemistry. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000260 [article] Effect of grinding media on zinc depression in a lead cleaner circuit [texte imprimé] / J. Kinal, Auteur ; C. Greet, Auteur ; I. Goode, Auteur . - 2009 . - pp. 759–765. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 759–765 Mots-clés : Froth  flotation  Grinding  Oxidation  Redox  reactions Résumé : Laboratory testwork, investigating the effect of high chrome grinding media in a lead regrind application has on subsequent metallurgical performance, was conducted at a large silver–lead–zinc operation in Australia. The initial data showed that the use of a more inert grinding media could have increased zinc losses to the lead cleaner concentrate if careful attention was not paid to alloy selection. Diagnostic tests showed that iron hydroxide surface coatings generated by grinding media corrosion reactions are an effective depressant for sphalerite in this ore body, even though it is known that an excess of these coatings could depress both galena and sphalerite flotation. These tests demonstrated that a 1% chrome alloy produced the desired pulp chemical conditions to yield an increase in lead concentrate grade through the rejection of sphalerite from the lead circuit. A plant trial was conducted in one of the two parallel grinding/flotation trains, and data collected for statistical analysis. During the plant trial, pulp chemical surveys of the regrind circuit were also taken to compare the effect of grinding media on the cleaner one feed slurry pulp potentials, dissolved oxygen, pH, temperature and EDTA extractable iron. The statistical analysis showed clearly that the change to 1% chrome grinding media had a significant positive impact on improving galena/sphalerite selectivity during lead cleaner flotation and improved the lead concentrate grade. The improved metallurgical performance is explained in terms of modified pulp chemistry. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000260

The effect of reagents on selective flotation of smithsonite–calcite–quartz / M. Irannajad in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 766–771 Titre : The effect of reagents on selective flotation of smithsonite–calcite–quartz Type de document : texte imprimé Auteurs : M. Irannajad, Auteur ; M. Ejtemaei, Auteur ; M. Gharabaghi, Auteur Année de publication : 2009 Article en page(s) : pp. 766–771 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Smithsonite  Calcite  Quartz  Microflotation Résumé : In this paper the effects of sodium sulphide, sodium hexa methaphosphate (SH), sodium fluoric, starch and sodium silicate adsorption on smithsonite, quartz and calcite surfaces at various pH values, and using Armac C and oleic acid as collectors were investigated through microflotation. Also, the effects of various primary amine collectors (Armac C, Armac T, Flotigam SA, Flotigam TA and Armeen TD) were investigated for smithsonite flotation. The flotation tests were performed using purified samples from Angooran mine by the microflotation technique. The cationic flotation results showed that the maximum recovery of smithsonite could be improved to 92% using 400 g/t Armac C and 500 g/t sodium sulphide at pH 11. Also, the quartz and calcite recoveries reached 98% and 89%, respectively, at the above mentioned conditions. Moreover, using 1250 g/t SH and 1500 g/t sodium silicate as a depressant, the quartz and calcite recoveries decreased to 70% and 20%, respectively, and also the smithsonite recovery was reduced to 82%. Furthermore, the experiments showed that the behavior of sodium fluoric as a quartz depressant is similar to that of sodium silicate. Flotation results using oleic acid revealed that the maximum recovery of 90% occurs at pH 9 and 500 g/t oleic acid. Also, the quartz and calcite recoveries reached 26% and 87%, respectively, in the anionic flotation conditions. Increasing amount of sodium silicate to 2000 g/t caused a decrease in the smithsonite recovery to 87% and also decreased the calcite and quartz recoveries by 10% and 15%, respectively. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000272 [article] The effect of reagents on selective flotation of smithsonite–calcite–quartz [texte imprimé] / M. Irannajad, Auteur ; M. Ejtemaei, Auteur ; M. Gharabaghi, Auteur . - 2009 . - pp. 766–771. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 766–771 Mots-clés : Smithsonite  Calcite  Quartz  Microflotation Résumé : In this paper the effects of sodium sulphide, sodium hexa methaphosphate (SH), sodium fluoric, starch and sodium silicate adsorption on smithsonite, quartz and calcite surfaces at various pH values, and using Armac C and oleic acid as collectors were investigated through microflotation. Also, the effects of various primary amine collectors (Armac C, Armac T, Flotigam SA, Flotigam TA and Armeen TD) were investigated for smithsonite flotation. The flotation tests were performed using purified samples from Angooran mine by the microflotation technique. The cationic flotation results showed that the maximum recovery of smithsonite could be improved to 92% using 400 g/t Armac C and 500 g/t sodium sulphide at pH 11. Also, the quartz and calcite recoveries reached 98% and 89%, respectively, at the above mentioned conditions. Moreover, using 1250 g/t SH and 1500 g/t sodium silicate as a depressant, the quartz and calcite recoveries decreased to 70% and 20%, respectively, and also the smithsonite recovery was reduced to 82%. Furthermore, the experiments showed that the behavior of sodium fluoric as a quartz depressant is similar to that of sodium silicate. Flotation results using oleic acid revealed that the maximum recovery of 90% occurs at pH 9 and 500 g/t oleic acid. Also, the quartz and calcite recoveries reached 26% and 87%, respectively, in the anionic flotation conditions. Increasing amount of sodium silicate to 2000 g/t caused a decrease in the smithsonite recovery to 87% and also decreased the calcite and quartz recoveries by 10% and 15%, respectively. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000272

Effect of curing under pressure on compressive strength development of cemented paste backfill / Erol Yilmaz in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 772–785 Titre : Effect of curing under pressure on compressive strength development of cemented paste backfill Type de document : texte imprimé Auteurs : Erol Yilmaz, Auteur ; Mostafa Benzaazoua, Auteur ; Tikou Belem, Auteur Année de publication : 2009 Article en page(s) : pp. 772–785 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Mine  tailings  Paste  backfill  Consolidation  Curing  stress  Compressive  strength Résumé : The mechanical performance of cemented paste backfill (CPB) placed in underground openings (e.g., mine stopes) often differs from laboratory-predicted performance, even under the same atmospheric curing conditions (ambient temperature and relative humidity). This is probably due to the specific self-weight consolidation, different drainage conditions and confinement pressures encountered in the paste backfilled stopes. A new test system named CUAPS (Curing Under Applied Pressure System) was designed at the Université du Québec en Abitibi-Témiscamingue (UQAT) to assess the hydro-mechanical performance of in situ CPB samples at laboratory scale. The CUAPS apparatus allows the effective curing of CPB samples subjected to an assortment of vertical pressure applications (curing under stresses) that can mimic in situ placement and consolidation conditions. The compressive strength development of CPB samples prepared from sulphide-rich mine tailings from Garpenberg polymetallic mine (Sweden) was investigated using CUAPS apparatus and conventional plastic moulds (unconsolidated undrained samples) in parallel. The effect of curing stress (i.e. simulating different consolidation conditions) on resultant geotechnical index parameters and hydromechanical properties of CPB samples was analyzed. The primary observation is the confirmation that the compressive strength development of the consolidated CPB samples is higher than that of unconsolidated undrained ones. It could be attributed to the removal of excess pore water mainly due to the applied pressure during the effective curing process, which seems to improve consolidation process of the CPB material. The results also account for the differences in the CPB strength observed between laboratory samples and in situ samples. Thus, CUAPS would be more suitable than conventional plastic moulds to collect data for preliminary and final design of CPB systems. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000478 [article] Effect of curing under pressure on compressive strength development of cemented paste backfill [texte imprimé] / Erol Yilmaz, Auteur ; Mostafa Benzaazoua, Auteur ; Tikou Belem, Auteur . - 2009 . - pp. 772–785. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 772–785 Mots-clés : Mine  tailings  Paste  backfill  Consolidation  Curing  stress  Compressive  strength Résumé : The mechanical performance of cemented paste backfill (CPB) placed in underground openings (e.g., mine stopes) often differs from laboratory-predicted performance, even under the same atmospheric curing conditions (ambient temperature and relative humidity). This is probably due to the specific self-weight consolidation, different drainage conditions and confinement pressures encountered in the paste backfilled stopes. A new test system named CUAPS (Curing Under Applied Pressure System) was designed at the Université du Québec en Abitibi-Témiscamingue (UQAT) to assess the hydro-mechanical performance of in situ CPB samples at laboratory scale. The CUAPS apparatus allows the effective curing of CPB samples subjected to an assortment of vertical pressure applications (curing under stresses) that can mimic in situ placement and consolidation conditions. The compressive strength development of CPB samples prepared from sulphide-rich mine tailings from Garpenberg polymetallic mine (Sweden) was investigated using CUAPS apparatus and conventional plastic moulds (unconsolidated undrained samples) in parallel. The effect of curing stress (i.e. simulating different consolidation conditions) on resultant geotechnical index parameters and hydromechanical properties of CPB samples was analyzed. The primary observation is the confirmation that the compressive strength development of the consolidated CPB samples is higher than that of unconsolidated undrained ones. It could be attributed to the removal of excess pore water mainly due to the applied pressure during the effective curing process, which seems to improve consolidation process of the CPB material. The results also account for the differences in the CPB strength observed between laboratory samples and in situ samples. Thus, CUAPS would be more suitable than conventional plastic moulds to collect data for preliminary and final design of CPB systems. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000478

Accumulation of dissolved gases at hydrophobic surfaces in water and sodium chloride solutions / Marc A. Hampton in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 786–792 Titre : Accumulation of dissolved gases at hydrophobic surfaces in water and sodium chloride solutions : Implications for coal flotation Type de document : texte imprimé Auteurs : Marc A. Hampton, Auteur ; Anh V. Nguyen, Auteur Année de publication : 2009 Article en page(s) : pp. 786–792 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Coal  Froth  flotation  Mineral  processing Résumé : Dissolved gases can preferentially accumulate at the hydrophobic solid–water interface as revealed by neutron reflectivity measurements. In this paper, atomic force microscopy (AFM) was used to examine accumulation of dissolved gases at a hydrophobic surface in water and sodium chloride solutions. The solvent-exchange method was used to artificially form gaseous domains accumulated at the interface suitable for AFM imaging. Smooth graphite surfaces were used as model surfaces to minimize the secondary effect of surface roughness on the imaging. The concentration of NaCl up to 1 M was found to have a negligible influence on the geometry and population of pre-existing nanobubbles, nanopancakes and nanobubble–nanopancake composites. The implications of the findings on coal flotation in saline water are discussed in terms of attraction between hydrophobic surfaces in water, bubble–particle attachment and hydrophobic coagulation between particles. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900048X [article] Accumulation of dissolved gases at hydrophobic surfaces in water and sodium chloride solutions : Implications for coal flotation [texte imprimé] / Marc A. Hampton, Auteur ; Anh V. Nguyen, Auteur . - 2009 . - pp. 786–792. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 786–792 Mots-clés : Coal  Froth  flotation  Mineral  processing Résumé : Dissolved gases can preferentially accumulate at the hydrophobic solid–water interface as revealed by neutron reflectivity measurements. In this paper, atomic force microscopy (AFM) was used to examine accumulation of dissolved gases at a hydrophobic surface in water and sodium chloride solutions. The solvent-exchange method was used to artificially form gaseous domains accumulated at the interface suitable for AFM imaging. Smooth graphite surfaces were used as model surfaces to minimize the secondary effect of surface roughness on the imaging. The concentration of NaCl up to 1 M was found to have a negligible influence on the geometry and population of pre-existing nanobubbles, nanopancakes and nanobubble–nanopancake composites. The implications of the findings on coal flotation in saline water are discussed in terms of attraction between hydrophobic surfaces in water, bubble–particle attachment and hydrophobic coagulation between particles. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900048X

An environmentally friendly design for low-grade diasporic-bauxite processing / Shu-hua Ma in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 793–798 Titre : An environmentally friendly design for low-grade diasporic-bauxite processing Type de document : texte imprimé Auteurs : Shu-hua Ma, Auteur ; Zong-guo Wen, Auteur ; Ji-ning Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 793–798 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Non-ferrous  metallic  ores  Digestion  Environmental  Mineral  economics Résumé : A new environmentally friendly design for low-grade diasporic-bauxite processing which is different from the Bayer and sintering processes was proposed in this paper. In the redesign of alumina production technology, a mixture of bauxite ore and sodium hydroxide solution was heated at a higher temperature for the purpose of complete decomposition of bauxite. The products were then extracted by water; the resulting sodium aluminate solution was further purified and used for the gibbsite precipitation, the residue being reacted with a caustic liquor to recover sodium oxide and alumina. The experimental results show that during the new process bauxite decomposition rates approach 100% and the residues can be easily recovered. When diasporic ores with mass ratio of alumina to silica of approximately 5:1 are treated, total alumina recovery efficiency of 86% and a sodium oxide presence below 1.5% in the final red mud will be achieved. This new design surpasses previous approaches in terms of high resource efficiency and low environmental impact. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000491 [article] An environmentally friendly design for low-grade diasporic-bauxite processing [texte imprimé] / Shu-hua Ma, Auteur ; Zong-guo Wen, Auteur ; Ji-ning Chen, Auteur . - 2009 . - pp. 793–798. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 793–798 Mots-clés : Non-ferrous  metallic  ores  Digestion  Environmental  Mineral  economics Résumé : A new environmentally friendly design for low-grade diasporic-bauxite processing which is different from the Bayer and sintering processes was proposed in this paper. In the redesign of alumina production technology, a mixture of bauxite ore and sodium hydroxide solution was heated at a higher temperature for the purpose of complete decomposition of bauxite. The products were then extracted by water; the resulting sodium aluminate solution was further purified and used for the gibbsite precipitation, the residue being reacted with a caustic liquor to recover sodium oxide and alumina. The experimental results show that during the new process bauxite decomposition rates approach 100% and the residues can be easily recovered. When diasporic ores with mass ratio of alumina to silica of approximately 5:1 are treated, total alumina recovery efficiency of 86% and a sodium oxide presence below 1.5% in the final red mud will be achieved. This new design surpasses previous approaches in terms of high resource efficiency and low environmental impact. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000491

Evaluation of leaching parameters for a refractory gold ore containing aurostibite and antimony minerals / G. Deschênes in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 799–808 Titre : Evaluation of leaching parameters for a refractory gold ore containing aurostibite and antimony minerals : Part I – Central zone Type de document : texte imprimé Auteurs : G. Deschênes, Auteur ; C. Xia, Auteur ; M. Fulton, Auteur Année de publication : 2009 Article en page(s) : pp. 799–808 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Gold  Aurostibite  Stibnite  Lead  nitrate  Sulphide  Freewest  Cyanide  Hydroseparation Résumé : A cyanidation study was conducted on a mild refractory gold ore sample from the Central zone of Clarence Stream Property, owned by Freewest Resources Canada, to develop a leaching strategy to extract gold. Gold, at a grade of 8.00 g/t, is present as native gold, electrum and aurostibite. The ore also contains 2.8% pyrrhotite, together with several antimony minerals (0.8% berthierite and gudmundite, 0.18% native antimony and stibnite). It also exhibits weak preg-robbing properties with 0.16% organic carbon. Aurostibite, a gold antimony compound, is particularly known to be insoluble in cyanide solution. The antimony dissolves in cyanide solution to form antimonates, which retards gold dissolution. Industrial practice of extracting gold from aurostibite generally consists of producing a flotation concentrate, which is leached in a pipe reactor at low alkalinity and high oxygen pressure with about 20 g/L cyanide. The proposed new approach is efficient and allows the extraction of gold directly from an ore at atmospheric pressure and a low cyanide concentration at pH 10.5. The effects of grinding, pre-treatment, lead nitrate, kerosene and cyanide concentrations have been investigated. The maximum gold extraction obtained on the ore was 87.9% using 800 ppm NaCN, 500 g/t lead nitrate, 30 g/t kerosene, DO (dissolved oxygen) 10 ppm and pH 10.5 in 168 h. The associated cyanide consumption was 1.3 kg/t. The additions of lead nitrate and kerosene increased gold extraction. In comparison to a P80 of 74 μm, a P80 of 30 μm significantly increased gold extraction. Gold in solid solution in gudmundite and arsenopyrite was believed to be responsible for the un-leached fraction until mineralogical analysis of hydroseparation concentrates of leach residues showed that most of the un-leached gold occurs as aurostibite, either as locked grains in sulphides/sulpharsenides or as grains with passivation rims of an Au–Sb–O phase. Coarse gold was also found. Gold extraction was not sensitive to cyanide concentration from 250 to 1200 ppm NaCN and high pH was detrimental. Decreasing the cyanide concentration reduced the cyanide consumption from 1.39 to 0.85 kg/t. The removal of coarse gold using a Knelson concentrator and a Mosley table prior to leaching increased the gold extraction to 90.4% (leach residue at 0.77 g/t). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000508 [article] Evaluation of leaching parameters for a refractory gold ore containing aurostibite and antimony minerals : Part I – Central zone [texte imprimé] / G. Deschênes, Auteur ; C. Xia, Auteur ; M. Fulton, Auteur . - 2009 . - pp. 799–808. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 799–808 Mots-clés : Gold  Aurostibite  Stibnite  Lead  nitrate  Sulphide  Freewest  Cyanide  Hydroseparation Résumé : A cyanidation study was conducted on a mild refractory gold ore sample from the Central zone of Clarence Stream Property, owned by Freewest Resources Canada, to develop a leaching strategy to extract gold. Gold, at a grade of 8.00 g/t, is present as native gold, electrum and aurostibite. The ore also contains 2.8% pyrrhotite, together with several antimony minerals (0.8% berthierite and gudmundite, 0.18% native antimony and stibnite). It also exhibits weak preg-robbing properties with 0.16% organic carbon. Aurostibite, a gold antimony compound, is particularly known to be insoluble in cyanide solution. The antimony dissolves in cyanide solution to form antimonates, which retards gold dissolution. Industrial practice of extracting gold from aurostibite generally consists of producing a flotation concentrate, which is leached in a pipe reactor at low alkalinity and high oxygen pressure with about 20 g/L cyanide. The proposed new approach is efficient and allows the extraction of gold directly from an ore at atmospheric pressure and a low cyanide concentration at pH 10.5. The effects of grinding, pre-treatment, lead nitrate, kerosene and cyanide concentrations have been investigated. The maximum gold extraction obtained on the ore was 87.9% using 800 ppm NaCN, 500 g/t lead nitrate, 30 g/t kerosene, DO (dissolved oxygen) 10 ppm and pH 10.5 in 168 h. The associated cyanide consumption was 1.3 kg/t. The additions of lead nitrate and kerosene increased gold extraction. In comparison to a P80 of 74 μm, a P80 of 30 μm significantly increased gold extraction. Gold in solid solution in gudmundite and arsenopyrite was believed to be responsible for the un-leached fraction until mineralogical analysis of hydroseparation concentrates of leach residues showed that most of the un-leached gold occurs as aurostibite, either as locked grains in sulphides/sulpharsenides or as grains with passivation rims of an Au–Sb–O phase. Coarse gold was also found. Gold extraction was not sensitive to cyanide concentration from 250 to 1200 ppm NaCN and high pH was detrimental. Decreasing the cyanide concentration reduced the cyanide consumption from 1.39 to 0.85 kg/t. The removal of coarse gold using a Knelson concentrator and a Mosley table prior to leaching increased the gold extraction to 90.4% (leach residue at 0.77 g/t). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000508

Ball motion, axial segregation and power consumption in a full scale two chamber cement mill / Paul W. Cleary in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 809–820 Titre : Ball motion, axial segregation and power consumption in a full scale two chamber cement mill Type de document : texte imprimé Auteurs : Paul W. Cleary, Auteur Année de publication : 2009 Article en page(s) : pp. 809–820 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : DEM  Mill  Cement  Grinding  Particle  flow Résumé : Grinding of clinker for cement production is often performed in a two chamber ball mill. In the first shorter chamber, raw feed is ground using media consisting of large balls. The ground product of the first chamber exits through a discharge grate and enters the second longer chamber. Here smaller balls are used to grind the product material even finer. In this paper we analyse the charge motion, short term ball segregation processes and energy utilisation in a 4 m diameter cement ball mill using DEM. The power draw predicted is consistent with the rated power of the mill. The energy dissipation in the mill is dominated by shear interaction. The gentle liner profiles ensure that few balls move on cataracting trajectories. The distribution of energy utilisation between the different size media fractions is explored as are differences in the collisional environment between the two mill chambers. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900051X [article] Ball motion, axial segregation and power consumption in a full scale two chamber cement mill [texte imprimé] / Paul W. Cleary, Auteur . - 2009 . - pp. 809–820. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 809–820 Mots-clés : DEM  Mill  Cement  Grinding  Particle  flow Résumé : Grinding of clinker for cement production is often performed in a two chamber ball mill. In the first shorter chamber, raw feed is ground using media consisting of large balls. The ground product of the first chamber exits through a discharge grate and enters the second longer chamber. Here smaller balls are used to grind the product material even finer. In this paper we analyse the charge motion, short term ball segregation processes and energy utilisation in a 4 m diameter cement ball mill using DEM. The power draw predicted is consistent with the rated power of the mill. The energy dissipation in the mill is dominated by shear interaction. The gentle liner profiles ensure that few balls move on cataracting trajectories. The distribution of energy utilisation between the different size media fractions is explored as are differences in the collisional environment between the two mill chambers. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900051X

The measurement of chalcopyrite content in rocks and slurries using magnetic resonance / Daniel Bennett in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 821–825 Titre : The measurement of chalcopyrite content in rocks and slurries using magnetic resonance Type de document : texte imprimé Auteurs : Daniel Bennett, Auteur ; David Miljak, Auteur ; Joe Khachan, Auteur Année de publication : 2009 Article en page(s) : pp. 821–825 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulphide  ores  Ore  mineralogy  Sorting  methods  Process  optimisation  Online  analysis Résumé : A prototype mineral analyser using magnetic resonance has been configured with two sensors for measurement of the copper sulphide mineral chalcopyrite (CuFeS2) in ores and slurries. In the first configuration, a sensor was optimised to quantify chalcopyrite content in rock fragments. The detection limit for these measurements was estimated at 15 mg of contained chalcopyrite in rock fragments of mass range of 1.4–3.7 g. The magnetic resonance results correlated with separate quantitative X-ray diffraction measurements of chalcopyrite content. The second configuration was used to quantify chalcopyrite content in mineral slurries. Tests on prepared slurry samples with known chalcopyrite concentration were performed, yielding a standard error of 0.1 wt% across the sample range of 0.5–4.0 wt%. Measurements on a commercial mineral slurry were also performed. The design of an online industrial analyser is discussed with reference to processing slurries with high solid loadings, containing phases such as chalcopyrite and other minerals. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000521 [article] The measurement of chalcopyrite content in rocks and slurries using magnetic resonance [texte imprimé] / Daniel Bennett, Auteur ; David Miljak, Auteur ; Joe Khachan, Auteur . - 2009 . - pp. 821–825. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 821–825 Mots-clés : Sulphide  ores  Ore  mineralogy  Sorting  methods  Process  optimisation  Online  analysis Résumé : A prototype mineral analyser using magnetic resonance has been configured with two sensors for measurement of the copper sulphide mineral chalcopyrite (CuFeS2) in ores and slurries. In the first configuration, a sensor was optimised to quantify chalcopyrite content in rock fragments. The detection limit for these measurements was estimated at 15 mg of contained chalcopyrite in rock fragments of mass range of 1.4–3.7 g. The magnetic resonance results correlated with separate quantitative X-ray diffraction measurements of chalcopyrite content. The second configuration was used to quantify chalcopyrite content in mineral slurries. Tests on prepared slurry samples with known chalcopyrite concentration were performed, yielding a standard error of 0.1 wt% across the sample range of 0.5–4.0 wt%. Measurements on a commercial mineral slurry were also performed. The design of an online industrial analyser is discussed with reference to processing slurries with high solid loadings, containing phases such as chalcopyrite and other minerals. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000521

Economic performance assessment of two ROM ore milling circuit controllers / Donghui Wei in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 826–839 Titre : Economic performance assessment of two ROM ore milling circuit controllers Type de document : texte imprimé Auteurs : Donghui Wei, Auteur ; Ian K. Craig, Auteur Année de publication : 2009 Article en page(s) : pp. 826–839 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Mineral  processing  Mineral  economics  Particle  size  Grinding  Flotation  Process  control Résumé : Economic performance assessment of control systems is receiving increasing attention in both academia and industry. A relevant framework is proposed in Bauer and Craig (Bauer, M., Craig, I.K., 2008. Economic assessment of advanced process control – a survey and framework. Journal of Process Control 18 (1), 2–18) based on a comprehensive survey of the methods for economic analysis of advanced process control systems. The framework provides a formal procedure for the economic assessment of control systems. A practically motivated simulation study is used to cast the economic performance assessment of a nonlinear model predictive controller and three single-loop PID controllers for a run-of-mine milling circuit into this framework. Performance functions of the milling circuit, which dynamically relate the circuit process variables to monetary values, are developed based on a survey study on milling circuits and an in-depth literature study. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000673 [article] Economic performance assessment of two ROM ore milling circuit controllers [texte imprimé] / Donghui Wei, Auteur ; Ian K. Craig, Auteur . - 2009 . - pp. 826–839. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 826–839 Mots-clés : Mineral  processing  Mineral  economics  Particle  size  Grinding  Flotation  Process  control Résumé : Economic performance assessment of control systems is receiving increasing attention in both academia and industry. A relevant framework is proposed in Bauer and Craig (Bauer, M., Craig, I.K., 2008. Economic assessment of advanced process control – a survey and framework. Journal of Process Control 18 (1), 2–18) based on a comprehensive survey of the methods for economic analysis of advanced process control systems. The framework provides a formal procedure for the economic assessment of control systems. A practically motivated simulation study is used to cast the economic performance assessment of a nonlinear model predictive controller and three single-loop PID controllers for a run-of-mine milling circuit into this framework. Performance functions of the milling circuit, which dynamically relate the circuit process variables to monetary values, are developed based on a survey study on milling circuits and an in-depth literature study. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000673

Suitability of bentonite-paste tailings mixtures as engineering barrier material for mine waste containment facilities / M. Fall in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 840–848 Titre : Suitability of bentonite-paste tailings mixtures as engineering barrier material for mine waste containment facilities Type de document : texte imprimé Auteurs : M. Fall, Auteur ; J. C. Célestin, Auteur ; F.S. Han, Auteur Année de publication : 2009 Article en page(s) : pp. 840–848 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Paste  backfill  Tailings  Acid  mine  drainage  Recycling  Barrier Résumé : This study investigates the feasibility of using bentonite-paste tailings (BPT) as a barrier (liner, cover) material for mine waste containment facilities. Improvements of the hydraulic properties are realized by using compaction to densify the paste tailings in the first stage and mixing an additive-like natural bentonite to paste tailings to further reduce the voids that control hydraulic conductivity in the second stage. A significant decrease in hydraulic conductivity is observed with these transformations. Values that are as low as 1 × 10−9 and 4 × 10−9 cm/s are obtained in 8% and 4% bentonite and BPT, respectively. Based on these satisfactory values, additional investigations are conducted to evaluate the freeze–thaw and wet–drying performance of BPT up to 5 and 6 cycles, respectively. The results show that negligible to acceptable changes in hydraulic conductivity occur. None of the changes reach one order of magnitude. As a final step, a cost analysis is undertaken to evaluate the economical benefits that can be obtained from such new material. When compared to conventional compacted clay–bentonite barrier or sand–bentonite with 12% bentonite concentration, it is found that the 4% BPT is less expensive by 66%. The results place this recycled BPT material as a promising candidate for barrier design while reducing the amount of waste to be managed and the cost of surface tailings management. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000685 [article] Suitability of bentonite-paste tailings mixtures as engineering barrier material for mine waste containment facilities [texte imprimé] / M. Fall, Auteur ; J. C. Célestin, Auteur ; F.S. Han, Auteur . - 2009 . - pp. 840–848. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 840–848 Mots-clés : Paste  backfill  Tailings  Acid  mine  drainage  Recycling  Barrier Résumé : This study investigates the feasibility of using bentonite-paste tailings (BPT) as a barrier (liner, cover) material for mine waste containment facilities. Improvements of the hydraulic properties are realized by using compaction to densify the paste tailings in the first stage and mixing an additive-like natural bentonite to paste tailings to further reduce the voids that control hydraulic conductivity in the second stage. A significant decrease in hydraulic conductivity is observed with these transformations. Values that are as low as 1 × 10−9 and 4 × 10−9 cm/s are obtained in 8% and 4% bentonite and BPT, respectively. Based on these satisfactory values, additional investigations are conducted to evaluate the freeze–thaw and wet–drying performance of BPT up to 5 and 6 cycles, respectively. The results show that negligible to acceptable changes in hydraulic conductivity occur. None of the changes reach one order of magnitude. As a final step, a cost analysis is undertaken to evaluate the economical benefits that can be obtained from such new material. When compared to conventional compacted clay–bentonite barrier or sand–bentonite with 12% bentonite concentration, it is found that the 4% BPT is less expensive by 66%. The results place this recycled BPT material as a promising candidate for barrier design while reducing the amount of waste to be managed and the cost of surface tailings management. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000685

Substituent effects in kaolinite flotation using dodecyl tertiary amines / Changmiao Liu in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 849–852 Titre : Substituent effects in kaolinite flotation using dodecyl tertiary amines Type de document : texte imprimé Auteurs : Changmiao Liu, Auteur ; Yuehua Hu, Auteur ; Xuefeng Cao, Auteur Année de publication : 2009 Article en page(s) : pp. 849–852 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  collectors  Oxide  ores  Froth  flotation Résumé : The flotation behavior of kaolinite was investigated using a series of tertiary amines (DRN, DEN, DPN and DBN). Maximum recoveries of kaolinite were 93%, 88% and 84% for DEN, DPN and DRN, respectively. The recovery for DBN was very low. On the basis of the Zeta potential and FT-IR spectra, the ionization of surface hydroxyl and the isomorphic exchange of surface ions accounts for the charging mechanisms of the kaolinite surface. The adsorption mechanism of tertiary amines onto the kaolinite surface was mainly electrostatic. We determined that the IEP of kaolinite increased from 3.4 to higher values after the interaction of kaolinite with the four tertiary amines. FT-IR spectra of kaolinite changed to include sharp peaks of tertiary amines. Inductive electronic effects and space-steric effects of –CH3, –C2H5, –C3H7 and –C7H7 bound to the N atom result in different collecting powers for the four tertiary amines. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000739 [article] Substituent effects in kaolinite flotation using dodecyl tertiary amines [texte imprimé] / Changmiao Liu, Auteur ; Yuehua Hu, Auteur ; Xuefeng Cao, Auteur . - 2009 . - pp. 849–852. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 849–852 Mots-clés : Flotation  collectors  Oxide  ores  Froth  flotation Résumé : The flotation behavior of kaolinite was investigated using a series of tertiary amines (DRN, DEN, DPN and DBN). Maximum recoveries of kaolinite were 93%, 88% and 84% for DEN, DPN and DRN, respectively. The recovery for DBN was very low. On the basis of the Zeta potential and FT-IR spectra, the ionization of surface hydroxyl and the isomorphic exchange of surface ions accounts for the charging mechanisms of the kaolinite surface. The adsorption mechanism of tertiary amines onto the kaolinite surface was mainly electrostatic. We determined that the IEP of kaolinite increased from 3.4 to higher values after the interaction of kaolinite with the four tertiary amines. FT-IR spectra of kaolinite changed to include sharp peaks of tertiary amines. Inductive electronic effects and space-steric effects of –CH3, –C2H5, –C3H7 and –C7H7 bound to the N atom result in different collecting powers for the four tertiary amines. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000739

Precipitation of Al(OH)3 crystals from supersaturated sodium aluminate solution irradiated with ultrasonic sound / Bin Zhang in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 853–858 Titre : Precipitation of Al(OH)3 crystals from supersaturated sodium aluminate solution irradiated with ultrasonic sound Type de document : texte imprimé Auteurs : Bin Zhang, Auteur ; Jie Li, Auteur ; Qiyuan Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 853–858 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Ultrasound  Supersaturated  aluminate  solution  Gibbsite  Precipitation  Crystallization Résumé : The influence of ultrasonic irradiation on precipitation of Al(OH)3 crystals from supersaturated aluminate solution has been investigated under batch condition of isothermal crystallization. The results indicated that, the precipitation rate was greatly increased by ultrasonic irradiation. Compared with general process, the time of precipitation ratio from 0% to 45% was reduced about 15 h under the irradiation of 20 kHz, and also 33 kHz. The effect of ultrasound on the precipitation process varies with ultrasound frequency. Irradiation of 33 kHz ultrasound shortens the induction period and increases the second nucleation, while 20 kHz enhance agglomeration and growth of Al(OH)3 which result in the increasing of the average diameter of final product by around 5 μm. Raman spectra and UV-absorbance analysis indicated that ultrasound is beneficial to the formation of sodium–aluminate ion pair, which will increase the decomposition rate of supersaturated aluminate solution. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000806 [article] Precipitation of Al(OH)3 crystals from supersaturated sodium aluminate solution irradiated with ultrasonic sound [texte imprimé] / Bin Zhang, Auteur ; Jie Li, Auteur ; Qiyuan Chen, Auteur . - 2009 . - pp. 853–858. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 853–858 Mots-clés : Ultrasound  Supersaturated  aluminate  solution  Gibbsite  Precipitation  Crystallization Résumé : The influence of ultrasonic irradiation on precipitation of Al(OH)3 crystals from supersaturated aluminate solution has been investigated under batch condition of isothermal crystallization. The results indicated that, the precipitation rate was greatly increased by ultrasonic irradiation. Compared with general process, the time of precipitation ratio from 0% to 45% was reduced about 15 h under the irradiation of 20 kHz, and also 33 kHz. The effect of ultrasound on the precipitation process varies with ultrasound frequency. Irradiation of 33 kHz ultrasound shortens the induction period and increases the second nucleation, while 20 kHz enhance agglomeration and growth of Al(OH)3 which result in the increasing of the average diameter of final product by around 5 μm. Raman spectra and UV-absorbance analysis indicated that ultrasound is beneficial to the formation of sodium–aluminate ion pair, which will increase the decomposition rate of supersaturated aluminate solution. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000806

CFD analysis of an induration cooler on an iron ore grate-kiln pelletising process / T.N. Croft in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 859–873 Titre : CFD analysis of an induration cooler on an iron ore grate-kiln pelletising process Type de document : texte imprimé Auteurs : T.N. Croft, Auteur ; M. Cross, Auteur ; A.K. Slone, Auteur Année de publication : 2009 Article en page(s) : pp. 859–873 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Iron  ore  pellet  induration  Computational  fluid  dynamics  Computational  modelling  Grate-kiln  process Résumé : During the re-configuration of their grate-kiln induration system for the firing of iron ore pellets at the Whyalla Steelworks, caused by a change from an earthy hematite to a magnetite ore with considerably less flux, OneSteel commissioned a detailed thermal flow analysis of the design options on the existing cooler in support of the process change. A key objective of this investigation was to decide if and where one might locate baffle walls within the cooler to improve the process and to control the off-gas flows to earlier stages within the process. The thermo-fluid analysis comprised the development of comprehensive three dimensional computational models of gas flow through the cooler coupled with the heat transport and exchange with the cooling pellet bed. The models were implemented within the context of an open source – object based computational fluid dynamics (CFD) simulation software framework. This paper describes the development of the CFD model, its verification and application to evaluating design options to improve the flow control within the cooler. In particular, the analysis considers the role and potential location of above bed baffle walls, cooler stack butterfly lid opening and its exhaust pressure on the flow distribution to the exit flow ducts from the cooler. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000946 [article] CFD analysis of an induration cooler on an iron ore grate-kiln pelletising process [texte imprimé] / T.N. Croft, Auteur ; M. Cross, Auteur ; A.K. Slone, Auteur . - 2009 . - pp. 859–873. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 859–873 Mots-clés : Iron  ore  pellet  induration  Computational  fluid  dynamics  Computational  modelling  Grate-kiln  process Résumé : During the re-configuration of their grate-kiln induration system for the firing of iron ore pellets at the Whyalla Steelworks, caused by a change from an earthy hematite to a magnetite ore with considerably less flux, OneSteel commissioned a detailed thermal flow analysis of the design options on the existing cooler in support of the process change. A key objective of this investigation was to decide if and where one might locate baffle walls within the cooler to improve the process and to control the off-gas flows to earlier stages within the process. The thermo-fluid analysis comprised the development of comprehensive three dimensional computational models of gas flow through the cooler coupled with the heat transport and exchange with the cooling pellet bed. The models were implemented within the context of an open source – object based computational fluid dynamics (CFD) simulation software framework. This paper describes the development of the CFD model, its verification and application to evaluating design options to improve the flow control within the cooler. In particular, the analysis considers the role and potential location of above bed baffle walls, cooler stack butterfly lid opening and its exhaust pressure on the flow distribution to the exit flow ducts from the cooler. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000946

Frother persistence / F. Azgomi in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 874–878 Titre : Frother persistence : A measure using gas holdup Type de document : texte imprimé Auteurs : F. Azgomi, Auteur ; C.O. Gomez, Auteur ; J.A. Finch, Auteur Année de publication : 2009 Article en page(s) : pp. 874–878 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  frothers Résumé : Persistence here refers to the how long a frother remains effective in producing small bubbles, one of its prime functions in flotation. One way to evaluate is to track gas holdup over time while air is sparged into a column: if frother is depleted bubble size will start to increase consequently increasing bubble rise velocity and hence decreasing gas holdup. Persistence of nine frothers was evaluated in this manner. Polyglycol frothers exhibited high persistence with gas holdup virtually constant over 50 h compared with alcohol frothers. The alcohols divided into two groups, one showing steady decline in gas holdup, e.g., 1-hexanol, and a second group exhibiting a sharp decline at a given time, e.g., MIBC. Tests on MIBC showed increasing concentration extended persistence while increasing gas velocity and increasing bubble size decreased persistence. The decrease in gas holdup was related directly to measured decrease in frother concentration. It appears that the transport of frother to and through the froth and from froth to atmosphere needs to be considered. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900096X [article] Frother persistence : A measure using gas holdup [texte imprimé] / F. Azgomi, Auteur ; C.O. Gomez, Auteur ; J.A. Finch, Auteur . - 2009 . - pp. 874–878. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 874–878 Mots-clés : Flotation  frothers Résumé : Persistence here refers to the how long a frother remains effective in producing small bubbles, one of its prime functions in flotation. One way to evaluate is to track gas holdup over time while air is sparged into a column: if frother is depleted bubble size will start to increase consequently increasing bubble rise velocity and hence decreasing gas holdup. Persistence of nine frothers was evaluated in this manner. Polyglycol frothers exhibited high persistence with gas holdup virtually constant over 50 h compared with alcohol frothers. The alcohols divided into two groups, one showing steady decline in gas holdup, e.g., 1-hexanol, and a second group exhibiting a sharp decline at a given time, e.g., MIBC. Tests on MIBC showed increasing concentration extended persistence while increasing gas velocity and increasing bubble size decreased persistence. The decrease in gas holdup was related directly to measured decrease in frother concentration. It appears that the transport of frother to and through the froth and from froth to atmosphere needs to be considered. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900096X

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