Dépouillements

Biochemical and genomic facets on the dissimilatory reduction of radionuclides by microorganisms / Bidyut R. Mohapatra in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 591–599 Titre : Biochemical and genomic facets on the dissimilatory reduction of radionuclides by microorganisms : A review Type de document : texte imprimé Auteurs : Bidyut R. Mohapatra, Auteur ; Orlando Dinardo, Auteur ; W. Douglas Gould, Auteur Année de publication : 2011 Article en page(s) : pp. 591–599 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Bioremediation  Bioreduction  Microorganisms  Radionuclides  Radionuclides  reduction  pathways Résumé : Development of environmentally sustainable technologies for remediation of radionuclides is paramount because of their long-term persistence in different ecological niches and acute toxic and teratogenic effects on human, terrestrial and aquatic life. The radionuclides U (VI), Tc (VII), Pu (VI) and Np (V) are enzymatically reduced to environmentally benign U (IV), Tc (IV), Pu (IV) and Np (IV), respectively by anaerobic microorganisms for production of energy and/or as a process of detoxification for their survival. These anaerobic microorganisms produce the oxidoreductase class of enzymes for the metabolism of radionuclides. These microorganisms have potential applications for the in situ environmentally friendly mitigation of radionuclides in subsurface environments. Appropriate knowledge on the biochemical and genetic pathways of radionuclides reduction by microorganisms will not only provide information on the fate and dynamics of these compounds in subsurface geological environments but also help to implement best management practice(s) for immobilization of these toxic compounds in waste effluents generated by the mining and nuclear industries. This review describes the phylogenetic diversity of radionuclides-reducing microorganisms present in the environment, various enzymatic systems associated with the reduction of radionuclides, and identification of genes involved in regulation of different enzymatic redox reactions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000609 [article] Biochemical and genomic facets on the dissimilatory reduction of radionuclides by microorganisms : A review [texte imprimé] / Bidyut R. Mohapatra, Auteur ; Orlando Dinardo, Auteur ; W. Douglas Gould, Auteur . - 2011 . - pp. 591–599. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 591–599 Mots-clés : Bioremediation  Bioreduction  Microorganisms  Radionuclides  Radionuclides  reduction  pathways Résumé : Development of environmentally sustainable technologies for remediation of radionuclides is paramount because of their long-term persistence in different ecological niches and acute toxic and teratogenic effects on human, terrestrial and aquatic life. The radionuclides U (VI), Tc (VII), Pu (VI) and Np (V) are enzymatically reduced to environmentally benign U (IV), Tc (IV), Pu (IV) and Np (IV), respectively by anaerobic microorganisms for production of energy and/or as a process of detoxification for their survival. These anaerobic microorganisms produce the oxidoreductase class of enzymes for the metabolism of radionuclides. These microorganisms have potential applications for the in situ environmentally friendly mitigation of radionuclides in subsurface environments. Appropriate knowledge on the biochemical and genetic pathways of radionuclides reduction by microorganisms will not only provide information on the fate and dynamics of these compounds in subsurface geological environments but also help to implement best management practice(s) for immobilization of these toxic compounds in waste effluents generated by the mining and nuclear industries. This review describes the phylogenetic diversity of radionuclides-reducing microorganisms present in the environment, various enzymatic systems associated with the reduction of radionuclides, and identification of genes involved in regulation of different enzymatic redox reactions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000609

Effect of grinding media on the activation of pyrite flotation / Yongjun Peng in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 600–605 Titre : Effect of grinding media on the activation of pyrite flotation Type de document : texte imprimé Auteurs : Yongjun Peng, Auteur ; Stephen Grano, Auteur Année de publication : 2011 Article en page(s) : pp. 600–605 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Grinding  media  Pyrite  flotation  Activation  Copper  Lead Résumé : In previous study, it has been found that the grinding conditions have a great effect on the flotation of chalcopyrite and galena as well as their separation from pyrite ( [Peng et al., 2003a] and [Peng et al., 2003b]). In this study, the effect of the grinding conditions on the activation of pyrite by Cu2+ and Pb2+ were investigated. Based on flotation behaviour, EDTA (ethylene diamine-tetra acid) extraction, pulp potential measurement and electrokinetic study, it is found that the activation of pyrite flotation by Cu2+ and Pb2+ involves different mechanisms. Reduction of copper(II) to copper(I) and the formation of new copper sulphide phases are responsible for the activation of pyrite flotation by Cu2+. This is an electrochemical process. However, adsorption of lead hydroxide on pyrite surface is principally responsible for the activation of pyrite flotation by Pb2+. The effect of grinding media on the flotation of pyrite activated by Cu2+ or Pb2+ is through the change of pulp potential and iron oxidation species emanating from the media. The iron oxidation species from grinding media is electrostatically repulsive with respect to copper-activated pyrite and therefore, reducing conditions produced by mild steel medium promotes pyrite flotation in the presence of Cu2+. However, iron oxidation species from grinding media is electrostatically attractive with respect to lead-activated pyrite and therefore inert grinding medium favours pyrite flotation in the presence of Pb2+. This study provides a clear picture of how to increase or decrease pyrite flotation through a smart selection of grinding media. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000397 [article] Effect of grinding media on the activation of pyrite flotation [texte imprimé] / Yongjun Peng, Auteur ; Stephen Grano, Auteur . - 2011 . - pp. 600–605. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 600–605 Mots-clés : Grinding  media  Pyrite  flotation  Activation  Copper  Lead Résumé : In previous study, it has been found that the grinding conditions have a great effect on the flotation of chalcopyrite and galena as well as their separation from pyrite ( [Peng et al., 2003a] and [Peng et al., 2003b]). In this study, the effect of the grinding conditions on the activation of pyrite by Cu2+ and Pb2+ were investigated. Based on flotation behaviour, EDTA (ethylene diamine-tetra acid) extraction, pulp potential measurement and electrokinetic study, it is found that the activation of pyrite flotation by Cu2+ and Pb2+ involves different mechanisms. Reduction of copper(II) to copper(I) and the formation of new copper sulphide phases are responsible for the activation of pyrite flotation by Cu2+. This is an electrochemical process. However, adsorption of lead hydroxide on pyrite surface is principally responsible for the activation of pyrite flotation by Pb2+. The effect of grinding media on the flotation of pyrite activated by Cu2+ or Pb2+ is through the change of pulp potential and iron oxidation species emanating from the media. The iron oxidation species from grinding media is electrostatically repulsive with respect to copper-activated pyrite and therefore, reducing conditions produced by mild steel medium promotes pyrite flotation in the presence of Cu2+. However, iron oxidation species from grinding media is electrostatically attractive with respect to lead-activated pyrite and therefore inert grinding medium favours pyrite flotation in the presence of Pb2+. This study provides a clear picture of how to increase or decrease pyrite flotation through a smart selection of grinding media. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000397

Ferric sulphate/chloride leaching of zinc and minor elements from a sphalerite concentrate / Sílvia M.C. Santos in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 606–615 Titre : Ferric sulphate/chloride leaching of zinc and minor elements from a sphalerite concentrate Type de document : texte imprimé Auteurs : Sílvia M.C. Santos, Auteur ; Remígio M. Machado, Auteur ; M. Joana N. Correia, Auteur Année de publication : 2011 Article en page(s) : pp. 606–615 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulphide  ores  Leaching  Hydrometallurgy  Zinc  Iron  oxidation Résumé : Atmospheric leaching of a sphalerite concentrate in sulphate and chloride media was performed and the effect of several variables, such as solid/liquid ratio and oxidant (Fe(III)) concentration were investigated. The behaviour of minor elements, such as Cu, In, As, Sb, Bi, Sn and Pb, was also studied under different conditions. The results showed that using a solid/liquid ratio of 5% (w/v) it was possible to leach 95% of zinc after 2 h, with a solution of 0.5 M H2SO4 and Fe2(SO4)3 at 80 °C. The minor elements As, Sb and Bi were also completely leached whereas copper leaching was favoured by the use of chloride medium. The oxidation of Fe(II) during the leaching tests was studied and an improvement of 20% zinc extraction was observed in an oxygenated system. Cross-current leach tests using two/three stages and a solid/liquid ratio of 10% (w/v) were performed to achieve 90% of zinc extraction. The electron microprobe analysis of the leaching residues showed no change on the sphalerite composition after the leaching, which indicates that the leaching of sphalerite involves the break down of the sulphide structure. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000415 [article] Ferric sulphate/chloride leaching of zinc and minor elements from a sphalerite concentrate [texte imprimé] / Sílvia M.C. Santos, Auteur ; Remígio M. Machado, Auteur ; M. Joana N. Correia, Auteur . - 2011 . - pp. 606–615. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 606–615 Mots-clés : Sulphide  ores  Leaching  Hydrometallurgy  Zinc  Iron  oxidation Résumé : Atmospheric leaching of a sphalerite concentrate in sulphate and chloride media was performed and the effect of several variables, such as solid/liquid ratio and oxidant (Fe(III)) concentration were investigated. The behaviour of minor elements, such as Cu, In, As, Sb, Bi, Sn and Pb, was also studied under different conditions. The results showed that using a solid/liquid ratio of 5% (w/v) it was possible to leach 95% of zinc after 2 h, with a solution of 0.5 M H2SO4 and Fe2(SO4)3 at 80 °C. The minor elements As, Sb and Bi were also completely leached whereas copper leaching was favoured by the use of chloride medium. The oxidation of Fe(II) during the leaching tests was studied and an improvement of 20% zinc extraction was observed in an oxygenated system. Cross-current leach tests using two/three stages and a solid/liquid ratio of 10% (w/v) were performed to achieve 90% of zinc extraction. The electron microprobe analysis of the leaching residues showed no change on the sphalerite composition after the leaching, which indicates that the leaching of sphalerite involves the break down of the sulphide structure. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000415

The influence of attrition milling on carbon dioxide sequestration on magnesium–iron silicate / Martin Fabian in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 616–620 Titre : The influence of attrition milling on carbon dioxide sequestration on magnesium–iron silicate Type de document : texte imprimé Auteurs : Martin Fabian, Auteur ; Maya Shopska, Auteur ; Daniela Paneva, Auteur Année de publication : 2011 Article en page(s) : pp. 616–620 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Olivine  Mechanical  activation  Mössbauer  spectroscopy  Carbon  dioxide  Adsorption Résumé : Present work evaluates the structural changes in olivine (Mg,Fe)2SiO4 (deposit Åheim, Norway) generated by mechanical treatment as well as its adsorption properties for carbon dioxide. The high-energy attrition milling was applied for mechanical activation. Identification of the mechanically-induced changes in the mineral was carried out applying various techniques: scanning electron microscopy, Mössbauer spectroscopy, specific surface measurements, carbon dioxide adsorption and Fourier-transformed infrared spectroscopy. The observed changes in the physico-chemical properties illustrate the possibility of the applied activation to modify the surface and/or bulk properties of olivine. Sensitivity for atmospheric CO2 sequestration as well as sequestration of CO2 by chemisorption can be derived from the obtained results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000427 [article] The influence of attrition milling on carbon dioxide sequestration on magnesium–iron silicate [texte imprimé] / Martin Fabian, Auteur ; Maya Shopska, Auteur ; Daniela Paneva, Auteur . - 2011 . - pp. 616–620. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 616–620 Mots-clés : Olivine  Mechanical  activation  Mössbauer  spectroscopy  Carbon  dioxide  Adsorption Résumé : Present work evaluates the structural changes in olivine (Mg,Fe)2SiO4 (deposit Åheim, Norway) generated by mechanical treatment as well as its adsorption properties for carbon dioxide. The high-energy attrition milling was applied for mechanical activation. Identification of the mechanically-induced changes in the mineral was carried out applying various techniques: scanning electron microscopy, Mössbauer spectroscopy, specific surface measurements, carbon dioxide adsorption and Fourier-transformed infrared spectroscopy. The observed changes in the physico-chemical properties illustrate the possibility of the applied activation to modify the surface and/or bulk properties of olivine. Sensitivity for atmospheric CO2 sequestration as well as sequestration of CO2 by chemisorption can be derived from the obtained results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000427

The effect of ore blends on the mineral processing of platinum ores / E. Van Tonder in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 621–626 Titre : The effect of ore blends on the mineral processing of platinum ores Type de document : texte imprimé Auteurs : E. Van Tonder, Auteur ; D.A. Deglon, Auteur ; T.J. Napier-Munn, Auteur Année de publication : 2011 Article en page(s) : pp. 621–626 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Ore  blends  Grinding  Froth  flotation Résumé : This paper investigates whether blends of platinum ores display linear grinding and flotation characteristics or whether non-linear effects occur, i.e. synergistic/antagonistic effects. Ores from four different shafts are used in the study, i.e. Salene, Waterval UG2, Paardekraal and Townlands. Laboratory grinding and flotation tests are conducted on blends of the four ores using a statistical simplex lattice mixture design. Grinding results show no evidence that blends of ores display non-linear grinding characteristics. Flotation results show significant antagonistic effects in binary blends of the Salene ore with the other ore types. On the other hand, ternary/quaternary blends of ores result in synergistic effects. The study concludes that blends of platinum ores display non-linear (non-additive) characteristics when there are large differences in metallurgical properties between the ore types. The study demonstrates that appropriately designed mixtures experiments are an effective way to study the performance of ore blends in the laboratory. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000440 [article] The effect of ore blends on the mineral processing of platinum ores [texte imprimé] / E. Van Tonder, Auteur ; D.A. Deglon, Auteur ; T.J. Napier-Munn, Auteur . - 2011 . - pp. 621–626. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 621–626 Mots-clés : Ore  blends  Grinding  Froth  flotation Résumé : This paper investigates whether blends of platinum ores display linear grinding and flotation characteristics or whether non-linear effects occur, i.e. synergistic/antagonistic effects. Ores from four different shafts are used in the study, i.e. Salene, Waterval UG2, Paardekraal and Townlands. Laboratory grinding and flotation tests are conducted on blends of the four ores using a statistical simplex lattice mixture design. Grinding results show no evidence that blends of ores display non-linear grinding characteristics. Flotation results show significant antagonistic effects in binary blends of the Salene ore with the other ore types. On the other hand, ternary/quaternary blends of ores result in synergistic effects. The study concludes that blends of platinum ores display non-linear (non-additive) characteristics when there are large differences in metallurgical properties between the ore types. The study demonstrates that appropriately designed mixtures experiments are an effective way to study the performance of ore blends in the laboratory. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000440

Mapping of soil nutrients in an abandoned Chinese coal mine and waste disposal site / Kostas Komnitsas in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 627–635 Titre : Mapping of soil nutrients in an abandoned Chinese coal mine and waste disposal site Type de document : texte imprimé Auteurs : Kostas Komnitsas, Auteur ; Xiangyun Guo, Auteur ; Daoliang Li, Auteur Année de publication : 2011 Article en page(s) : pp. 627–635 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Spatial  heterogeneity  Soil  nutrients  Geostatistics  Opencast  coal  mining Résumé : The present paper attempts to identify the spatial patterns of soil nutrients in the abandoned Haizhou opencast coal mine and waste disposal site, in China. A geostatistical approach was used to overcome problems due to the heterogeneity of the site (some parts have been abandoned for more than 30 years, lack of clean soil, presence of overburden and low-grade ore, co-disposal of wastes from adjacent sites) and the limited number of available samples. One hundred and eight soil samples were collected from an area of 332 ha and analyzed for pH, organic matter (OM), NH4–N, available phosphorus (AP) and available potassium (AK). The results indicate that nutrients exhibit different spatial distribution and only NH4–N showed strong spatial dependence and a relatively large nugget effect. Relatively high content of OM, NH4–N, AP and AK was seen in the northeastern part, whereas pH was higher in central north and southern parts of the site. The determination of the spatial variability and heterogeneity of nutrients in mining and waste disposal sites assesses the need for amendments and assists in the selection of the most feasible revegetation scheme. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000452 [article] Mapping of soil nutrients in an abandoned Chinese coal mine and waste disposal site [texte imprimé] / Kostas Komnitsas, Auteur ; Xiangyun Guo, Auteur ; Daoliang Li, Auteur . - 2011 . - pp. 627–635. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 627–635 Mots-clés : Spatial  heterogeneity  Soil  nutrients  Geostatistics  Opencast  coal  mining Résumé : The present paper attempts to identify the spatial patterns of soil nutrients in the abandoned Haizhou opencast coal mine and waste disposal site, in China. A geostatistical approach was used to overcome problems due to the heterogeneity of the site (some parts have been abandoned for more than 30 years, lack of clean soil, presence of overburden and low-grade ore, co-disposal of wastes from adjacent sites) and the limited number of available samples. One hundred and eight soil samples were collected from an area of 332 ha and analyzed for pH, organic matter (OM), NH4–N, available phosphorus (AP) and available potassium (AK). The results indicate that nutrients exhibit different spatial distribution and only NH4–N showed strong spatial dependence and a relatively large nugget effect. Relatively high content of OM, NH4–N, AP and AK was seen in the northeastern part, whereas pH was higher in central north and southern parts of the site. The determination of the spatial variability and heterogeneity of nutrients in mining and waste disposal sites assesses the need for amendments and assists in the selection of the most feasible revegetation scheme. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000452

Study of gas holdup and pressure characteristics in a column flotation cell using coal / Satish Chandra Shukla in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 636–642 Titre : Study of gas holdup and pressure characteristics in a column flotation cell using coal Type de document : texte imprimé Auteurs : Satish Chandra Shukla, Auteur ; Gautam Kundu, Auteur ; Dibyendu Mukherjee, Auteur Année de publication : 2011 Article en page(s) : pp. 636–642 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Coal  Column  flotation  Froth  flotation  Mineral  processing Résumé : Present work has been carried out to observe the effect of process variables (gas flow rate, feed flow rate, solid concentration and frother concentration) on gas holdup and pressure characteristics in flotation column using coal. Gas holdup has been estimated using phase separation method while piezometers have been used to obtain column’s axial pressure profile. It was observed that gas holdup in collection zone was affected by both air as well as feed flow rates. Up to 6% change in gas holdup may occur when the feed flow rate changes from 1–2 cm/s. It was also observed that addition of coal decreased the gas holdup while addition of methyl isobutyl carbinol (MIBC) had opposite effect. Almost linear variation in columns axial pressure characteristics has been observed with gas flow rate. An empirical relationship between gas holdup in the flotation column with column’s axial pressure difference was developed. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000610 [article] Study of gas holdup and pressure characteristics in a column flotation cell using coal [texte imprimé] / Satish Chandra Shukla, Auteur ; Gautam Kundu, Auteur ; Dibyendu Mukherjee, Auteur . - 2011 . - pp. 636–642. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 636–642 Mots-clés : Coal  Column  flotation  Froth  flotation  Mineral  processing Résumé : Present work has been carried out to observe the effect of process variables (gas flow rate, feed flow rate, solid concentration and frother concentration) on gas holdup and pressure characteristics in flotation column using coal. Gas holdup has been estimated using phase separation method while piezometers have been used to obtain column’s axial pressure profile. It was observed that gas holdup in collection zone was affected by both air as well as feed flow rates. Up to 6% change in gas holdup may occur when the feed flow rate changes from 1–2 cm/s. It was also observed that addition of coal decreased the gas holdup while addition of methyl isobutyl carbinol (MIBC) had opposite effect. Almost linear variation in columns axial pressure characteristics has been observed with gas flow rate. An empirical relationship between gas holdup in the flotation column with column’s axial pressure difference was developed. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000610

Cobalt recovery from mixed Co–Mn hydroxide precipitates by ammonia–ammonium carbonate leaching / A. Katsiapi in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 643–651 Titre : Cobalt recovery from mixed Co–Mn hydroxide precipitates by ammonia–ammonium carbonate leaching Type de document : texte imprimé Auteurs : A. Katsiapi, Auteur ; P.E. Tsakiridis, Auteur ; P. Oustadakis, Auteur Année de publication : 2011 Article en page(s) : pp. 643–651 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Cobalt  Manganese  Precipitation  Ammoniacal  leaching Résumé : The research work presented in this paper focused on the recovery of cobalt from mixed Co–Mn hydroxide precipitates (obtained from sulphate leach liquors of nickel oxide ore), using ammonia–ammonium carbonate leaching. The characterization of the initial mixed hydroxide precipitates, as well as the corresponding leached residue was carried out by X-ray Diffraction, TG–DTA and Scanning Electron Microscopy. Cobalt and manganese precipitation was based on the statistical design and analysis of experiments, in order to determine the main effects and interactions of the precipitation factors, which were the equilibrium pH and the temperature. Co and Mn were precipitated as hydroxides at pH = 10.5 and T = 25 °C, using 5 M NaOH as a neutralizing agent, by 99.9% and 99.5%, respectively. The main mineralogical phases were, Mn3O4 (Hausmannite), γ-Mn3O4 and CoMn2O4, while Co(OH)2 and Mn(OH)2 (Pyrochroite) were also present as minor constituents. Cobalt and manganese separation was based on selective cobalt recovery by ammonia–ammonium carbonate leaching of the produced mixed hydroxide precipitate. The factors studied were the ammonia–ammonium carbonate concentration and the solid to liquid ratio. The cobalt recovery efficiency reached 93%. Mn3O4 (Hausmannite) was the main mineralogical phase of the leached residue, while MnCO3 (Rhodochrosite) and Mn2O3 were also present. Small quantities of cobalt were also observed in the residue as CoMn2O4. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000622 [article] Cobalt recovery from mixed Co–Mn hydroxide precipitates by ammonia–ammonium carbonate leaching [texte imprimé] / A. Katsiapi, Auteur ; P.E. Tsakiridis, Auteur ; P. Oustadakis, Auteur . - 2011 . - pp. 643–651. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 643–651 Mots-clés : Cobalt  Manganese  Precipitation  Ammoniacal  leaching Résumé : The research work presented in this paper focused on the recovery of cobalt from mixed Co–Mn hydroxide precipitates (obtained from sulphate leach liquors of nickel oxide ore), using ammonia–ammonium carbonate leaching. The characterization of the initial mixed hydroxide precipitates, as well as the corresponding leached residue was carried out by X-ray Diffraction, TG–DTA and Scanning Electron Microscopy. Cobalt and manganese precipitation was based on the statistical design and analysis of experiments, in order to determine the main effects and interactions of the precipitation factors, which were the equilibrium pH and the temperature. Co and Mn were precipitated as hydroxides at pH = 10.5 and T = 25 °C, using 5 M NaOH as a neutralizing agent, by 99.9% and 99.5%, respectively. The main mineralogical phases were, Mn3O4 (Hausmannite), γ-Mn3O4 and CoMn2O4, while Co(OH)2 and Mn(OH)2 (Pyrochroite) were also present as minor constituents. Cobalt and manganese separation was based on selective cobalt recovery by ammonia–ammonium carbonate leaching of the produced mixed hydroxide precipitate. The factors studied were the ammonia–ammonium carbonate concentration and the solid to liquid ratio. The cobalt recovery efficiency reached 93%. Mn3O4 (Hausmannite) was the main mineralogical phase of the leached residue, while MnCO3 (Rhodochrosite) and Mn2O3 were also present. Small quantities of cobalt were also observed in the residue as CoMn2O4. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000622

Mössbauer quantification of pyrrhotite in relation to self-heating / A. Navarra in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 652–658 Titre : Mössbauer quantification of pyrrhotite in relation to self-heating Type de document : texte imprimé Auteurs : A. Navarra, Auteur ; J.T. Graham, Auteur ; S. Somot, Auteur Année de publication : 2011 Article en page(s) : pp. 652–658 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Analytical  methods  Mass  balancing  Sulphide  ores  Ore  handling  Ore  mineralogy Résumé : Pyrrhotite (Po) is widely considered the most significant mineral in the self-heating of sulphide ores and concentrates. It is therefore desirable to determine the amount of Po in a sample. This is commonly accomplished through X-ray diffraction (XRD) or quantitative evaluation of materials by scanning electron microscopy (QEM–SEM), neither of which are suited to oxidizing samples such as Po. The sample preparation for these methods often requires heating and drying, which may alter the composition. This paper introduces another quantitative method based on Mössbauer analysis, whose sample preparation is limited, and not as likely to alter the sample. The technique is tested using binary and ternary mixtures containing pyrrhotite with pentlandite (Pn), pyrite (Py) and sphalerite (Sp). A detection limit of 2 wt.% Po is easily obtained in the Po–Pn binary mixtures. The Po is also successfully measured in Pn–Po–Py and Sp–Po–Py mixtures; however, the presence of sphalerite increases the time required for an accurate measurement. The time required to measure Po in complex samples may be optimized through future work. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000932 [article] Mössbauer quantification of pyrrhotite in relation to self-heating [texte imprimé] / A. Navarra, Auteur ; J.T. Graham, Auteur ; S. Somot, Auteur . - 2011 . - pp. 652–658. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 652–658 Mots-clés : Analytical  methods  Mass  balancing  Sulphide  ores  Ore  handling  Ore  mineralogy Résumé : Pyrrhotite (Po) is widely considered the most significant mineral in the self-heating of sulphide ores and concentrates. It is therefore desirable to determine the amount of Po in a sample. This is commonly accomplished through X-ray diffraction (XRD) or quantitative evaluation of materials by scanning electron microscopy (QEM–SEM), neither of which are suited to oxidizing samples such as Po. The sample preparation for these methods often requires heating and drying, which may alter the composition. This paper introduces another quantitative method based on Mössbauer analysis, whose sample preparation is limited, and not as likely to alter the sample. The technique is tested using binary and ternary mixtures containing pyrrhotite with pentlandite (Pn), pyrite (Py) and sphalerite (Sp). A detection limit of 2 wt.% Po is easily obtained in the Po–Pn binary mixtures. The Po is also successfully measured in Pn–Po–Py and Sp–Po–Py mixtures; however, the presence of sphalerite increases the time required for an accurate measurement. The time required to measure Po in complex samples may be optimized through future work. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000932

New concepts for lithium minerals processing / Felix Brandt in Minerals engineering, Vol. 23 N° 8 (Juillet 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 659–661 Titre : New concepts for lithium minerals processing Type de document : texte imprimé Auteurs : Felix Brandt, Auteur ; Reiner Haus, Auteur Année de publication : 2011 Article en page(s) : pp. 659–661 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Industrial  minerals  Mineral  processing  Mineral  economics  Liberation  Comminution Résumé : A new concept for the enrichment of lithium minerals is offering higher purity and higher yield by applying new processing technologies addressing the specific properties of the pegmatitic host rock. Additional value is created from high quality by-products which will improve the sustainability of mining activity and the overall cost base. Within the new concept, flotation may even be avoided where wet separation techniques are not applicable. Two innovative processing technologies have been integrated in the new concept: electrodynamic fragmentation and optical sorting. Detailed results of lab-technical tests show that the new process design can achieve highly selective liberation and separation processes. Optical and mineralogical analyses of the test products indicate a high benefit for commercial applications. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000920 [article] New concepts for lithium minerals processing [texte imprimé] / Felix Brandt, Auteur ; Reiner Haus, Auteur . - 2011 . - pp. 659–661. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 8 (Juillet 2010) . - pp. 659–661 Mots-clés : Industrial  minerals  Mineral  processing  Mineral  economics  Liberation  Comminution Résumé : A new concept for the enrichment of lithium minerals is offering higher purity and higher yield by applying new processing technologies addressing the specific properties of the pegmatitic host rock. Additional value is created from high quality by-products which will improve the sustainability of mining activity and the overall cost base. Within the new concept, flotation may even be avoided where wet separation techniques are not applicable. Two innovative processing technologies have been integrated in the new concept: electrodynamic fragmentation and optical sorting. Detailed results of lab-technical tests show that the new process design can achieve highly selective liberation and separation processes. Optical and mineralogical analyses of the test products indicate a high benefit for commercial applications. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000920

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