Tomasz A Chmielewski - Academia.edu (original) (raw)
Papers by Tomasz A Chmielewski
Physicochemical Problems of Mineral Processing, 2013
Hydrometallurgical treatment of complex copper sulfidic ores, by-products and concentrates requir... more Hydrometallurgical treatment of complex copper sulfidic ores, by-products and concentrates requires aggressive, oxidative leaching methods and application of Fe(III) ions and oxygen or bacteria assisted environment. Leach liquors generated in the process are usually copper and iron-rich solutions of high acidity. Such conditions require the application of suitably strong and selective reagent to extract copper in SX operations. This paper discusses the copper extraction behavior of commercial copper rea- gents: LIX 984N, LIX 612N-LV and Acorga M5640. Aqueous feed solutions used in SX studies were PLS' generated in atmospheric leaching of commercial flotation concentrate, produced at Lubin Concen- trator (KGHM). McCabe-Thiele diagrams were generated and copper net transfer values were compared and discussed. It was shown that stronger modified aldoxime reagents (Acorga, LIX 612) are superior over non-modified salicylaldoxime/ketoxime mixture (LIX 984N). Particularly, the ester mo...
Simultaneous measurements of pH and redox potential using a platinum electrode as well as potenti... more Simultaneous measurements of pH and redox potential using a platinum electrode as well as potential of copper sulphide electrodes during non-oxidative leaching of Lubin shale middlings with sulfuric acid have been applied to determine leaching kinetics and to evaluate its electrochemical parameters as well as to assess the changes taking place at the mineral/solution interface during leaching process. Significant decrease in both redox potential of the solution (from +350 mV to +50 mV, Ag,AgCl) and potential of mineral electrodes were observed with increasing pH during carbonate decomposition with sulfuric acid. It is therefore concluded that the low value of red-ox potential is a parameter preventing oxidation of copper sulphide minerals present in leached material and prevents the transition of Cu and Fe to the solution. It was found that the non-oxidative leaching is a rapid and selective process, resulting in decomposition of calcium and magnesium carbonates and in saturation of...
Ammonia has been widely applied as an effective leaching agent in numerous hydrometallurgical pro... more Ammonia has been widely applied as an effective leaching agent in numerous hydrometallurgical processes for many years. Ammonia can be effectively used for leaching of base metals (Cu, Ni, Co, Zn) as well as for precious metals (Ag, Au) because of formation of soluble, very strong ammonia complexes. Moreover, ammonia has been considered as an attractive leaching agent due to its low toxicity, low costs and ease of regeneration by evaporation from alkaline solutions. An important advantage of ammonia environment in hydrometallurgy is its selectivity in terms of solubilization of desired metals and precipitation of undesirable iron in one unit operation (Meng and Han, 1996). Ammonia leaching can be used in non-oxidative, oxidative and reductive leaching. It was first applied and developed for recovery of copper from its metallic and oxide raw materials. Copper forms well soluble and very stable complexes ([Cu(NH3)4] ) and can be leached at ambient conditions due to the excellent solub...
Rapidly declining quality of copper concentrates produced by Lubin Concentrator of KGHM Polska Mi... more Rapidly declining quality of copper concentrates produced by Lubin Concentrator of KGHM Polska Miedz SA, having very low content of Cu, high content of Pb, As and organic carbon as well as significant contents of Ag, Co, Ni, Zn, Re, V and Mo, makes the concentrates difficult-to-process by flash smelting. Currently hydrometallurgy, using sulfuric acid in the presence of iron(III) and oxygen as a leaching medium for base metals and chloride leaching for silver and lead, seems to be an alternative for pyrometallurgy. The goal of the work is to discuss main aspects of the necessity of application a new hydrometallurgical technology, based on different unit operations, including non-oxidative atmospheric, chloride and pressure leaching, recovery of Pb and Ag, separation of Cu and accompanying metals from PLS and arsenic neutralization. The unique lithological, mineralogical and chemical properties of the process feed were discussed in details. The results of laboratory investigations performed at the Wroclaw University of Technology and assumptions of the process scale-up for acquisition of data for full scale technology were summarized. Planned investigations on the pilot plant scale will provide technical and economic data for a pre-feasibility study of the future hydrometallurgical plant.
Physicochemical Problems of Mineral Processing, 2017
Recovery of silver and lead by means of chloride leaching of solid residue after atmospheric leac... more Recovery of silver and lead by means of chloride leaching of solid residue after atmospheric leaching of the copper concentrate from Lubin Concentrator (KGHM) was investigated. The effect of leaching temperature, chloride concentration, Fe(III) and oxygen presence, solid-to-liquid ratio and feed preleaching with NaOH on the silver and lead recovery was analyzed. Chloride leaching appeared to be very effective for recovery of lead, whereas satisfactory recovery of silver was observed after chemical pretreatment of the leaching feed with alkali solution of NaOH in order to liberate Ag entrapped in the jarosite structure. It was found that to achieve the satisfactory recovery of Ag and Pb leaching had to be performed in acidified 4 M chloride concentration at temperature of 90 C. The presence of oxidants, that is O2 and iron(III) ions, was beneficial in the initial stage of the process. The maximum recovery of Ag and Pb was found for the solid-to-liquid ratio of 1:10 after 10 hours lea...
Chalcopyrite as a major and most abundant copper mineral is also known as the most resistant to l... more Chalcopyrite as a major and most abundant copper mineral is also known as the most resistant to leaching. In particular, oxidative leaching of chalcopyrite in lower temperatures is affected by numerous problems such as a formation of passive layers on the chalcopyrite surface. A low grade deposit of copper is the next problem with recovering copper, because a conventional smelter technology is not cost-effective. Several methods of processing of copper sulphide ores, by-product or concentrates were invented and applied world wide in various scale. Most of them were characterized in the literature and presented during international conferences.
Physicochemical Problems of Mineral Processing, 2011
Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ore... more Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ores and concentrates from Lubin Concentrator, have been carried out. Moreover, measurements of sulfide-sulfide contact potential and galvanic current were also performed using deoxygenated sulphuric acid solutions as well as the solutions saturated with oxygen and containing Fe(III) ions. Significant galvanic interactions were observed for sulfide couples exhibiting high potential difference, particularly when copper sulfides were short-circuited with pyrite. According to mineralogical data for Lubin polymineral copper concentrate, chalcocite and bornite are dominating with chalcopyrite and covellite as minor copper minerals. Expected is advantageous affect of pyrite in promoting the kinetics of copper leaching from Lubin concentrate as a result of observed galvanic interactions between pyrite and copper sulfides.
The pregnant solution after atmospheric leaching of cupriferous shale (middlings from Lubin Conce... more The pregnant solution after atmospheric leaching of cupriferous shale (middlings from Lubin Concentrator) with sulphuric acid and/or with sulphuric acid containing Fe(III) in the presence of oxygen were applied for solvent extraction experiments with several extractants. The ...
Laboratory investigations have been undertaken in order to determine the influence of major param... more Laboratory investigations have been undertaken in order to determine the influence of major parameters on the process of leaching of metal values from ocean nodules by means of model "sea- water", that is - acidified chloride solutions. The effect of leaching conditions, i.e. time, temperature, stirring rate, liquid/solid ratio and HCl concentration was examined on leaching efficiency. It was found that concentration of hydrochloric acid greatly influences leaching of metals from ocean nodules. At HCl concentration exceeding 4.0 M and at 30 o C of temperature all valuable metals were almost completely leached out from the feed. Elevation of the leaching temperature allowed for reduction of the initial HCl concentration. Deep-sea nodules studied in this work exhibited somewhat different leaching behavior that reported in the literature.
j o u r n a l h o m e p a g e H w w w . m i n p r o c . p w r . w r o c . p l / j o u r n a l / M... more j o u r n a l h o m e p a g e H w w w . m i n p r o c . p w r . w r o c . p l / j o u r n a l / Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ores and concentrates from Lubin Concentrator, have been carried out. Moreover, measurements of sulfide-sulfide contact potential and galvanic current were also performed using deoxygenated sulphuric acid solutions as well as the solutions saturated with oxygen and containing Fe(III) ions. Significant galvanic interactions were observed for sulfide couples exhibiting high potential difference, particularly when copper sulfides were short-circuited with pyrite. According to mineralogical data for Lubin polymineral copper concentrate, chalcocite and bornite are dominating with chalcopyrite and covellite as minor copper minerals. Expected is advantageous affect of pyrite in promoting the kinetics of copper leaching from Lubin concentrate as a result of observed galvanic interactions between pyrite a...
Fizykochemiczne Problemy Mineralurgii
The effect of initial temperature, sulphuric acid concentration and oxygen partial pressure on pr... more The effect of initial temperature, sulphuric acid concentration and oxygen partial pressure on pressure leaching of shale fraction of copper ore is presented. Leaching was performed in the autoclave in the temperature range of 100 -180 0 C using oxygen as an oxidizing agent. Tailigs from 1 st cleaning of Lubin Concentrator (ZWR Lubin) were used as a shale material exhibiting elevated contents of metals and organic carbon. Process was performed at sulphuric acid concentration from 20 to 50 g/dm 3 . The high efficiency of pressure leaching for copper, cobalt, nickel, iron and zinc from polimetallic shale middlings of the Lubin Concentrator was revealed.
![Research paper thumbnail of Galvanic interactions of sulfide minerals in leaching of flotation concentrate from lubin concentrator [Oddziaływania galwaniczne minerałów siarczkowych podczas ługowania koncentratu flotacyjnego z ZWR Lubin]](https://attachments.academia-assets.com/74483034/thumbnails/1.jpg)
](Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ore... more Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ores and concentrates from Lubin Concentrator, have been carried out. Moreover, measurements of sulfide-sulfide contact potential and galvanic current were also performed using deoxygenated sulphuric acid solutions as well as the solutions saturated with oxygen and containing Fe(III) ions. Significant galvanic interactions were observed for sulfide couples exhibiting high potential difference, particularly when copper sulfides were short-circuited with pyrite. According to mineralogical data for Lubin polymineral copper concentrate, chalcocite and bornite are dominating with chalcopyrite and covellite as minor copper minerals. Expected is advantageous affect of pyrite in promoting the kinetics of copper leaching from Lubin concentrate as a result of observed galvanic interactions between pyrite and copper sulfides.
Minerals Engineering, 1989
ABSTRACT The voltammetric measurements on galena is potassium ethyl xanthate (KEtX) aqueous solut... more ABSTRACT The voltammetric measurements on galena is potassium ethyl xanthate (KEtX) aqueous solutions have been conducted to establish the conditions od appearance of a peak responsible for the surface reaction between glena and EtX− ions. This peak was recorded at potentials much lower than equilibrium potential (ER) calculated for the Pb(EtX)2 formation in a bulk process (PbS + 2EtX− = Pb(EtX)2 + So + 2e−). The adsorption potential Ea and the value of its shift (ΔE=0.12V) in relation to the equilibrium potential of Pb(EtX)2 formation have been determined from positions of both anodic and cathodic peaks observed for the surface process. The value of ΔE corresponds to a free energy change which is equal to 2.77 kcal/mole (11.59 kJ/mol).
During the second quarter of work on this new project, critical review of the literature continue... more During the second quarter of work on this new project, critical review of the literature continued. Several new references related to gravity separation were identified and evaluated. A synopsis was assembled to summarize techniques developed by various researchers for the float/sink
Physicochemical Problems of Mineral …, 2009
... future technological alterations(Chmielewski, 2007, Konopaca et al., 2007, Wódka et al., 2007... more ... future technological alterations(Chmielewski, 2007, Konopaca et al., 2007, Wódka et al., 2007 ... values remain in flotation tailings and leads to hardly accepted met-als loses ... the recovery and concentrate grade have been decreasing remarkably, particularly at Lubin Concentra-tor ...
Simultaneous measurements of pH and redox potential using a platinum electrode as well as potenti... more Simultaneous measurements of pH and redox potential using a platinum electrode as well as potential of copper sulphide electrodes during non-oxidative leaching of Lubin shale middlings with sulfuric acid have been applied to determine leaching kinetics and to evaluate its electrochemical parameters as well as to assess the changes taking place at the mineral/solution interface during leaching process. Significant decrease in both redox potential of the solution (from +350 mV to +50 mV, Ag,AgCl) and potential of mineral electrodes were observed with increasing pH during carbonate decomposition with sulfuric acid. It is therefore concluded that the low value of red-ox potential is a parameter preventing oxidation of copper sulphide minerals present in leached material and prevents the transition of Cu and Fe to the solution. It was found that the non-oxidative leaching is a rapid and selective process, resulting in decomposition of calcium and magnesium carbonates and in saturation of the leaching slurry with carbon dioxide. It was recognized that with the increasing degree of carbonate decomposition from 50 to 100 % metalsbearing minerals liberation has remarkably improved, which beneficially facilitates and intensifies further upgrading or leaching processes.
Minerals Engineering, 2008
Bioshale is a project co-funded by the European Commission (FP6 programme) that started in Octobe... more Bioshale is a project co-funded by the European Commission (FP6 programme) that started in October 2004. The main objective of the Bioshale project is to define innovative biotechnological processes for 'environmentally-aware' exploitation of black shale ores. Three black shale deposits have been chosen as targets of the R&D actions. These include one deposit that exists under natural conditions (Talvivaara, Finland), one currently being processed (Lubin, Poland) and one after mining (Mansfeld, Germany). The black shale ores contain base, precious and 'high-tech' and rare metals but also high contents of organic matter that handicap metal recovery by conventional techniques. In summary, the main technical aspects of the work plan are:-evaluation of the geological resources & selection of metal-bearing raw materials;-selection of biological consortia to be tested for mineral processing;-assessment of hydrometallurgical routes, including bioprocessing, for metals recovery;-technical-economic evaluation of new processes from mining to metal recovery including social and environmental impacts. An overview of the main results of the work in progress by the 13 European partners (from 8 countries) is presented.
Journal of Chemical Technology & Biotechnology, 2007
Process of rhenium removal from acidic industrial efluents by pressure reduction with gaseous hyd... more Process of rhenium removal from acidic industrial efluents by pressure reduction with gaseous hydrogen and sulphur dioxide was examined. Solutions from two sources were investigated, namely: circulating wash liquors originated from a wet dedusting of converter gases, and ...
Physicochemical Problems of Mineral Processing, 2013
Hydrometallurgical treatment of complex copper sulfidic ores, by-products and concentrates requir... more Hydrometallurgical treatment of complex copper sulfidic ores, by-products and concentrates requires aggressive, oxidative leaching methods and application of Fe(III) ions and oxygen or bacteria assisted environment. Leach liquors generated in the process are usually copper and iron-rich solutions of high acidity. Such conditions require the application of suitably strong and selective reagent to extract copper in SX operations. This paper discusses the copper extraction behavior of commercial copper rea- gents: LIX 984N, LIX 612N-LV and Acorga M5640. Aqueous feed solutions used in SX studies were PLS' generated in atmospheric leaching of commercial flotation concentrate, produced at Lubin Concen- trator (KGHM). McCabe-Thiele diagrams were generated and copper net transfer values were compared and discussed. It was shown that stronger modified aldoxime reagents (Acorga, LIX 612) are superior over non-modified salicylaldoxime/ketoxime mixture (LIX 984N). Particularly, the ester mo...
Simultaneous measurements of pH and redox potential using a platinum electrode as well as potenti... more Simultaneous measurements of pH and redox potential using a platinum electrode as well as potential of copper sulphide electrodes during non-oxidative leaching of Lubin shale middlings with sulfuric acid have been applied to determine leaching kinetics and to evaluate its electrochemical parameters as well as to assess the changes taking place at the mineral/solution interface during leaching process. Significant decrease in both redox potential of the solution (from +350 mV to +50 mV, Ag,AgCl) and potential of mineral electrodes were observed with increasing pH during carbonate decomposition with sulfuric acid. It is therefore concluded that the low value of red-ox potential is a parameter preventing oxidation of copper sulphide minerals present in leached material and prevents the transition of Cu and Fe to the solution. It was found that the non-oxidative leaching is a rapid and selective process, resulting in decomposition of calcium and magnesium carbonates and in saturation of...
Ammonia has been widely applied as an effective leaching agent in numerous hydrometallurgical pro... more Ammonia has been widely applied as an effective leaching agent in numerous hydrometallurgical processes for many years. Ammonia can be effectively used for leaching of base metals (Cu, Ni, Co, Zn) as well as for precious metals (Ag, Au) because of formation of soluble, very strong ammonia complexes. Moreover, ammonia has been considered as an attractive leaching agent due to its low toxicity, low costs and ease of regeneration by evaporation from alkaline solutions. An important advantage of ammonia environment in hydrometallurgy is its selectivity in terms of solubilization of desired metals and precipitation of undesirable iron in one unit operation (Meng and Han, 1996). Ammonia leaching can be used in non-oxidative, oxidative and reductive leaching. It was first applied and developed for recovery of copper from its metallic and oxide raw materials. Copper forms well soluble and very stable complexes ([Cu(NH3)4] ) and can be leached at ambient conditions due to the excellent solub...
Rapidly declining quality of copper concentrates produced by Lubin Concentrator of KGHM Polska Mi... more Rapidly declining quality of copper concentrates produced by Lubin Concentrator of KGHM Polska Miedz SA, having very low content of Cu, high content of Pb, As and organic carbon as well as significant contents of Ag, Co, Ni, Zn, Re, V and Mo, makes the concentrates difficult-to-process by flash smelting. Currently hydrometallurgy, using sulfuric acid in the presence of iron(III) and oxygen as a leaching medium for base metals and chloride leaching for silver and lead, seems to be an alternative for pyrometallurgy. The goal of the work is to discuss main aspects of the necessity of application a new hydrometallurgical technology, based on different unit operations, including non-oxidative atmospheric, chloride and pressure leaching, recovery of Pb and Ag, separation of Cu and accompanying metals from PLS and arsenic neutralization. The unique lithological, mineralogical and chemical properties of the process feed were discussed in details. The results of laboratory investigations performed at the Wroclaw University of Technology and assumptions of the process scale-up for acquisition of data for full scale technology were summarized. Planned investigations on the pilot plant scale will provide technical and economic data for a pre-feasibility study of the future hydrometallurgical plant.
Physicochemical Problems of Mineral Processing, 2017
Recovery of silver and lead by means of chloride leaching of solid residue after atmospheric leac... more Recovery of silver and lead by means of chloride leaching of solid residue after atmospheric leaching of the copper concentrate from Lubin Concentrator (KGHM) was investigated. The effect of leaching temperature, chloride concentration, Fe(III) and oxygen presence, solid-to-liquid ratio and feed preleaching with NaOH on the silver and lead recovery was analyzed. Chloride leaching appeared to be very effective for recovery of lead, whereas satisfactory recovery of silver was observed after chemical pretreatment of the leaching feed with alkali solution of NaOH in order to liberate Ag entrapped in the jarosite structure. It was found that to achieve the satisfactory recovery of Ag and Pb leaching had to be performed in acidified 4 M chloride concentration at temperature of 90 C. The presence of oxidants, that is O2 and iron(III) ions, was beneficial in the initial stage of the process. The maximum recovery of Ag and Pb was found for the solid-to-liquid ratio of 1:10 after 10 hours lea...
Chalcopyrite as a major and most abundant copper mineral is also known as the most resistant to l... more Chalcopyrite as a major and most abundant copper mineral is also known as the most resistant to leaching. In particular, oxidative leaching of chalcopyrite in lower temperatures is affected by numerous problems such as a formation of passive layers on the chalcopyrite surface. A low grade deposit of copper is the next problem with recovering copper, because a conventional smelter technology is not cost-effective. Several methods of processing of copper sulphide ores, by-product or concentrates were invented and applied world wide in various scale. Most of them were characterized in the literature and presented during international conferences.
Physicochemical Problems of Mineral Processing, 2011
Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ore... more Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ores and concentrates from Lubin Concentrator, have been carried out. Moreover, measurements of sulfide-sulfide contact potential and galvanic current were also performed using deoxygenated sulphuric acid solutions as well as the solutions saturated with oxygen and containing Fe(III) ions. Significant galvanic interactions were observed for sulfide couples exhibiting high potential difference, particularly when copper sulfides were short-circuited with pyrite. According to mineralogical data for Lubin polymineral copper concentrate, chalcocite and bornite are dominating with chalcopyrite and covellite as minor copper minerals. Expected is advantageous affect of pyrite in promoting the kinetics of copper leaching from Lubin concentrate as a result of observed galvanic interactions between pyrite and copper sulfides.
The pregnant solution after atmospheric leaching of cupriferous shale (middlings from Lubin Conce... more The pregnant solution after atmospheric leaching of cupriferous shale (middlings from Lubin Concentrator) with sulphuric acid and/or with sulphuric acid containing Fe(III) in the presence of oxygen were applied for solvent extraction experiments with several extractants. The ...
Laboratory investigations have been undertaken in order to determine the influence of major param... more Laboratory investigations have been undertaken in order to determine the influence of major parameters on the process of leaching of metal values from ocean nodules by means of model "sea- water", that is - acidified chloride solutions. The effect of leaching conditions, i.e. time, temperature, stirring rate, liquid/solid ratio and HCl concentration was examined on leaching efficiency. It was found that concentration of hydrochloric acid greatly influences leaching of metals from ocean nodules. At HCl concentration exceeding 4.0 M and at 30 o C of temperature all valuable metals were almost completely leached out from the feed. Elevation of the leaching temperature allowed for reduction of the initial HCl concentration. Deep-sea nodules studied in this work exhibited somewhat different leaching behavior that reported in the literature.
j o u r n a l h o m e p a g e H w w w . m i n p r o c . p w r . w r o c . p l / j o u r n a l / M... more j o u r n a l h o m e p a g e H w w w . m i n p r o c . p w r . w r o c . p l / j o u r n a l / Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ores and concentrates from Lubin Concentrator, have been carried out. Moreover, measurements of sulfide-sulfide contact potential and galvanic current were also performed using deoxygenated sulphuric acid solutions as well as the solutions saturated with oxygen and containing Fe(III) ions. Significant galvanic interactions were observed for sulfide couples exhibiting high potential difference, particularly when copper sulfides were short-circuited with pyrite. According to mineralogical data for Lubin polymineral copper concentrate, chalcocite and bornite are dominating with chalcopyrite and covellite as minor copper minerals. Expected is advantageous affect of pyrite in promoting the kinetics of copper leaching from Lubin concentrate as a result of observed galvanic interactions between pyrite a...
Fizykochemiczne Problemy Mineralurgii
The effect of initial temperature, sulphuric acid concentration and oxygen partial pressure on pr... more The effect of initial temperature, sulphuric acid concentration and oxygen partial pressure on pressure leaching of shale fraction of copper ore is presented. Leaching was performed in the autoclave in the temperature range of 100 -180 0 C using oxygen as an oxidizing agent. Tailigs from 1 st cleaning of Lubin Concentrator (ZWR Lubin) were used as a shale material exhibiting elevated contents of metals and organic carbon. Process was performed at sulphuric acid concentration from 20 to 50 g/dm 3 . The high efficiency of pressure leaching for copper, cobalt, nickel, iron and zinc from polimetallic shale middlings of the Lubin Concentrator was revealed.
Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ore... more Measurements of the rest potential of copper sulfide electrodes and pyrite, present in copper ores and concentrates from Lubin Concentrator, have been carried out. Moreover, measurements of sulfide-sulfide contact potential and galvanic current were also performed using deoxygenated sulphuric acid solutions as well as the solutions saturated with oxygen and containing Fe(III) ions. Significant galvanic interactions were observed for sulfide couples exhibiting high potential difference, particularly when copper sulfides were short-circuited with pyrite. According to mineralogical data for Lubin polymineral copper concentrate, chalcocite and bornite are dominating with chalcopyrite and covellite as minor copper minerals. Expected is advantageous affect of pyrite in promoting the kinetics of copper leaching from Lubin concentrate as a result of observed galvanic interactions between pyrite and copper sulfides.
Minerals Engineering, 1989
ABSTRACT The voltammetric measurements on galena is potassium ethyl xanthate (KEtX) aqueous solut... more ABSTRACT The voltammetric measurements on galena is potassium ethyl xanthate (KEtX) aqueous solutions have been conducted to establish the conditions od appearance of a peak responsible for the surface reaction between glena and EtX− ions. This peak was recorded at potentials much lower than equilibrium potential (ER) calculated for the Pb(EtX)2 formation in a bulk process (PbS + 2EtX− = Pb(EtX)2 + So + 2e−). The adsorption potential Ea and the value of its shift (ΔE=0.12V) in relation to the equilibrium potential of Pb(EtX)2 formation have been determined from positions of both anodic and cathodic peaks observed for the surface process. The value of ΔE corresponds to a free energy change which is equal to 2.77 kcal/mole (11.59 kJ/mol).
During the second quarter of work on this new project, critical review of the literature continue... more During the second quarter of work on this new project, critical review of the literature continued. Several new references related to gravity separation were identified and evaluated. A synopsis was assembled to summarize techniques developed by various researchers for the float/sink
Physicochemical Problems of Mineral …, 2009
... future technological alterations(Chmielewski, 2007, Konopaca et al., 2007, Wódka et al., 2007... more ... future technological alterations(Chmielewski, 2007, Konopaca et al., 2007, Wódka et al., 2007 ... values remain in flotation tailings and leads to hardly accepted met-als loses ... the recovery and concentrate grade have been decreasing remarkably, particularly at Lubin Concentra-tor ...
Simultaneous measurements of pH and redox potential using a platinum electrode as well as potenti... more Simultaneous measurements of pH and redox potential using a platinum electrode as well as potential of copper sulphide electrodes during non-oxidative leaching of Lubin shale middlings with sulfuric acid have been applied to determine leaching kinetics and to evaluate its electrochemical parameters as well as to assess the changes taking place at the mineral/solution interface during leaching process. Significant decrease in both redox potential of the solution (from +350 mV to +50 mV, Ag,AgCl) and potential of mineral electrodes were observed with increasing pH during carbonate decomposition with sulfuric acid. It is therefore concluded that the low value of red-ox potential is a parameter preventing oxidation of copper sulphide minerals present in leached material and prevents the transition of Cu and Fe to the solution. It was found that the non-oxidative leaching is a rapid and selective process, resulting in decomposition of calcium and magnesium carbonates and in saturation of the leaching slurry with carbon dioxide. It was recognized that with the increasing degree of carbonate decomposition from 50 to 100 % metalsbearing minerals liberation has remarkably improved, which beneficially facilitates and intensifies further upgrading or leaching processes.
Minerals Engineering, 2008
Bioshale is a project co-funded by the European Commission (FP6 programme) that started in Octobe... more Bioshale is a project co-funded by the European Commission (FP6 programme) that started in October 2004. The main objective of the Bioshale project is to define innovative biotechnological processes for 'environmentally-aware' exploitation of black shale ores. Three black shale deposits have been chosen as targets of the R&D actions. These include one deposit that exists under natural conditions (Talvivaara, Finland), one currently being processed (Lubin, Poland) and one after mining (Mansfeld, Germany). The black shale ores contain base, precious and 'high-tech' and rare metals but also high contents of organic matter that handicap metal recovery by conventional techniques. In summary, the main technical aspects of the work plan are:-evaluation of the geological resources & selection of metal-bearing raw materials;-selection of biological consortia to be tested for mineral processing;-assessment of hydrometallurgical routes, including bioprocessing, for metals recovery;-technical-economic evaluation of new processes from mining to metal recovery including social and environmental impacts. An overview of the main results of the work in progress by the 13 European partners (from 8 countries) is presented.
Journal of Chemical Technology & Biotechnology, 2007
Process of rhenium removal from acidic industrial efluents by pressure reduction with gaseous hyd... more Process of rhenium removal from acidic industrial efluents by pressure reduction with gaseous hydrogen and sulphur dioxide was examined. Solutions from two sources were investigated, namely: circulating wash liquors originated from a wet dedusting of converter gases, and ...