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Microwave roasting of a carbonaceous sulphidic gold concentrate / R. K. Amankwah in Minerals engineering, Vol. 22 N° 13 (Octobre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 13 (Octobre 2009) . - pp. 1095–1101 Titre : Microwave roasting of a carbonaceous sulphidic gold concentrate Type de document : texte imprimé Auteurs : R. K. Amankwah, Auteur ; C.A. Pickles, Auteur Année de publication : 2009 Article en page(s) : pp. 1095–1101 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Gold  ores  Oxidation  Roasting  Leaching  Cyanidation Résumé : Gold ores containing carbonaceous matter and sulphidic minerals are generally referred to as double refractory. Extraction of the gold from such ores usually requires an oxidation step to both liberate the ultra-fine gold from the matrix of the sulphides and remove the carbon that preg-robs the dissolved gold. In this investigation, a double refractory flotation concentrate was microwave roasted to oxidize both the sulphides and the carbonaceous matter. The concentrate was characterized by thermogravimetric and infrared analysis and the microwave absorbtion characteristics were quantified by determining the permittivities. The microwave heating behaviour studies showed that the sample temperature increased with increasing incident microwave power, processing time and sample mass. Due to the hyperactive response of the concentrate to the microwaves, a low incident power of 600 W was found to be suitable for roasting, as higher powers resulted in sintering and melting of the concentrate. The gold extraction values after cyanidation were over 96% and these were similar to those obtained by conventional roasting. The main advantages of microwave roasting were that both the total carbon removal rates and the heating rates were higher and the specific energy consumptions were lower than in conventional roasting. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000697 [article] Microwave roasting of a carbonaceous sulphidic gold concentrate [texte imprimé] / R. K. Amankwah, Auteur ; C.A. Pickles, Auteur . - 2009 . - pp. 1095–1101. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 13 (Octobre 2009) . - pp. 1095–1101 Mots-clés : Gold  ores  Oxidation  Roasting  Leaching  Cyanidation Résumé : Gold ores containing carbonaceous matter and sulphidic minerals are generally referred to as double refractory. Extraction of the gold from such ores usually requires an oxidation step to both liberate the ultra-fine gold from the matrix of the sulphides and remove the carbon that preg-robs the dissolved gold. In this investigation, a double refractory flotation concentrate was microwave roasted to oxidize both the sulphides and the carbonaceous matter. The concentrate was characterized by thermogravimetric and infrared analysis and the microwave absorbtion characteristics were quantified by determining the permittivities. The microwave heating behaviour studies showed that the sample temperature increased with increasing incident microwave power, processing time and sample mass. Due to the hyperactive response of the concentrate to the microwaves, a low incident power of 600 W was found to be suitable for roasting, as higher powers resulted in sintering and melting of the concentrate. The gold extraction values after cyanidation were over 96% and these were similar to those obtained by conventional roasting. The main advantages of microwave roasting were that both the total carbon removal rates and the heating rates were higher and the specific energy consumptions were lower than in conventional roasting. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000697

Microwaves in extractive metallurgy / C.A. Pickles in Minerals engineering, Vol. 22 N° 13 (Octobre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 13 (Octobre 2009) . - pp. 1102–1111 Titre : Microwaves in extractive metallurgy : Part 1 – Review of fundamentals Type de document : texte imprimé Auteurs : C.A. Pickles, Auteur Année de publication : 2009 Article en page(s) : pp. 1102–1111 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Oxide  ores  Extractive  metallurgy  Pyrometallurgy  Mineral  processing  Reduction Résumé : Microwave radiation is a relatively new energy source, which has considerable potential for various applications in mineral processing and extractive metallurgy. However, the strengths of the interaction of the microwave radiation with the materials of interest are largely unknown. Additionally, in contrast to the aqueous solutions used in hydrometallurgy, the microwave interaction with the heterogeneous solids used in pyrometallurgical processes is difficult to model from fundamentals. Since the microwave heating characteristics of most of the materials cannot be predicted, research is being performed to determine the underlying factors which govern the microwave response of ores, concentrates, reducing agents and other feedstocks used in pyrometallurgical processes. In the present research, the techniques used to measure the microwave coupling characteristics are outlined and the application of these techniques to some relevant pyrometallurgical materials is reviewed. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000703 [article] Microwaves in extractive metallurgy : Part 1 – Review of fundamentals [texte imprimé] / C.A. Pickles, Auteur . - 2009 . - pp. 1102–1111. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 13 (Octobre 2009) . - pp. 1102–1111 Mots-clés : Oxide  ores  Extractive  metallurgy  Pyrometallurgy  Mineral  processing  Reduction Résumé : Microwave radiation is a relatively new energy source, which has considerable potential for various applications in mineral processing and extractive metallurgy. However, the strengths of the interaction of the microwave radiation with the materials of interest are largely unknown. Additionally, in contrast to the aqueous solutions used in hydrometallurgy, the microwave interaction with the heterogeneous solids used in pyrometallurgical processes is difficult to model from fundamentals. Since the microwave heating characteristics of most of the materials cannot be predicted, research is being performed to determine the underlying factors which govern the microwave response of ores, concentrates, reducing agents and other feedstocks used in pyrometallurgical processes. In the present research, the techniques used to measure the microwave coupling characteristics are outlined and the application of these techniques to some relevant pyrometallurgical materials is reviewed. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000703

Microwaves in extractive metallurgy / C.A. Pickles in Minerals engineering, Vol. 22 N° 13 (Octobre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 13 (Octobre 2009) . - pp. 1112–1118 Titre : Microwaves in extractive metallurgy : Part 2 – A review of applications Type de document : texte imprimé Auteurs : C.A. Pickles, Auteur Année de publication : 2009 Article en page(s) : pp. 1112–1118 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Oxide  ores  Dewatering  Pyrometallurgy  Reduction  Extractive  metallurgy Résumé : In metal extraction processes, such as reduction or smelting, a source of energy is required for the endothermic reactions. This energy is often supplied by the combustion of carbonaceous materials or hydrocarbons or by inputting some electrical energy. Typically, large-scale reactors are used and the energy is transported to the reacting materials from the heat source via convective, conductive and radiative processes. Additionally, considerable heat is transferred to the containment vessel, the surroundings and the off-gases and this energy is difficult to recover. On the other hand, microwave heating systems can be designed such that only the material to be processed absorbs the microwaves, since microwave radiation is deposited directly in the material to be heated. Other potential advantages of microwave processing include; high energy densities, selective heating, improved control, environmental benefits and minimal off-gas generation. In the present research, the utilization of microwaves as an energy source in metal extraction and, in particular the pyrometallurgical processing of oxide ores, is reviewed. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000715 [article] Microwaves in extractive metallurgy : Part 2 – A review of applications [texte imprimé] / C.A. Pickles, Auteur . - 2009 . - pp. 1112–1118. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 13 (Octobre 2009) . - pp. 1112–1118 Mots-clés : Oxide  ores  Dewatering  Pyrometallurgy  Reduction  Extractive  metallurgy Résumé : In metal extraction processes, such as reduction or smelting, a source of energy is required for the endothermic reactions. This energy is often supplied by the combustion of carbonaceous materials or hydrocarbons or by inputting some electrical energy. Typically, large-scale reactors are used and the energy is transported to the reacting materials from the heat source via convective, conductive and radiative processes. Additionally, considerable heat is transferred to the containment vessel, the surroundings and the off-gases and this energy is difficult to recover. On the other hand, microwave heating systems can be designed such that only the material to be processed absorbs the microwaves, since microwave radiation is deposited directly in the material to be heated. Other potential advantages of microwave processing include; high energy densities, selective heating, improved control, environmental benefits and minimal off-gas generation. In the present research, the utilization of microwaves as an energy source in metal extraction and, in particular the pyrometallurgical processing of oxide ores, is reviewed. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000715

Thermodynamic modelling of the multiphase pyrometallurgical processing of electric arc furnace dust / C.A. Pickles in Minerals engineering, Vol. 22 N° 11 (Octobre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 977–985 Titre : Thermodynamic modelling of the multiphase pyrometallurgical processing of electric arc furnace dust Type de document : texte imprimé Auteurs : C.A. Pickles, Auteur Année de publication : 2009 Article en page(s) : pp. 977–985 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flue  dusts  Pyrometallurgy  Reduction  Recycling  Waste  processing Résumé : Electric arc furnace (EAF) dust is produced when automobile scrap is remelted in an electric arc furnace and about 10–20 kilograms are generated per ton of steel. The major elements present in the dust are usually zinc, iron and calcium with smaller amounts of numerous other elements such as lead, copper and nickel. Typically, in the pyrometallurgical EAF dust treatment processes, the lead and zinc are separated as a crude zinc oxide while the iron is generally not worth recovering. Copper and nickel are usually not recovered as they report either to the oxide residue or to any metallic iron that is produced. In the present research, the recovery of the non-ferrous metals in a multiphase system consisting of gas, slag, matte, metal and solid carbon phases was investigated. The equilibrium compositions of the various phases, resulting from the smelting of the dust, were calculated using the SOLGASMIX module of Outokumpu HSC Chemistry. The effects of the following operating variables were investigated; carbon additions, sulphur additions, nitrogen and oxygen additions, temperature and dust composition. The thermodynamic modelling results show that the majority of the non-ferrous metals can be recovered, with the zinc and lead concentrating in the gas phase and the nickel and copper concentrating in the matte phase. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000764 [article] Thermodynamic modelling of the multiphase pyrometallurgical processing of electric arc furnace dust [texte imprimé] / C.A. Pickles, Auteur . - 2009 . - pp. 977–985. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 977–985 Mots-clés : Flue  dusts  Pyrometallurgy  Reduction  Recycling  Waste  processing Résumé : Electric arc furnace (EAF) dust is produced when automobile scrap is remelted in an electric arc furnace and about 10–20 kilograms are generated per ton of steel. The major elements present in the dust are usually zinc, iron and calcium with smaller amounts of numerous other elements such as lead, copper and nickel. Typically, in the pyrometallurgical EAF dust treatment processes, the lead and zinc are separated as a crude zinc oxide while the iron is generally not worth recovering. Copper and nickel are usually not recovered as they report either to the oxide residue or to any metallic iron that is produced. In the present research, the recovery of the non-ferrous metals in a multiphase system consisting of gas, slag, matte, metal and solid carbon phases was investigated. The equilibrium compositions of the various phases, resulting from the smelting of the dust, were calculated using the SOLGASMIX module of Outokumpu HSC Chemistry. The effects of the following operating variables were investigated; carbon additions, sulphur additions, nitrogen and oxygen additions, temperature and dust composition. The thermodynamic modelling results show that the majority of the non-ferrous metals can be recovered, with the zinc and lead concentrating in the gas phase and the nickel and copper concentrating in the matte phase. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000764