Documents disponibles écrits par cet auteur

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

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

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