The pressure leaching mechanism of chalcopyrite was studied by both leaching tests and in-situ electrochemical measurements. The effects of leaching temperature, oxygen partial pressure, and calcium lignosulphonate, o...The pressure leaching mechanism of chalcopyrite was studied by both leaching tests and in-situ electrochemical measurements. The effects of leaching temperature, oxygen partial pressure, and calcium lignosulphonate, on copper extraction and iron extraction of chalcopyrite pressure leaching were investigated. The leaching rate is accelerated by increasing the leaching temperature from 120 to 150 ℃ and increasing oxygen partial pressure to 0.7 MPa. The release of iron is faster than that of copper due to the formation of iron-depleted sulfides. Under the optimal leaching conditions without calcium lignosulphonate, the copper and iron extraction rates are 79% and 81%, respectively. The leaching process is mixedly controlled by surface reaction and product layer diffusion with an activation energy of 36.61 k J/mol. Calcium lignosulphonate can effectively remove the sulfur passive layer, and the activation energy is 45.59 k J/mol, suggesting that the leaching process with calcium lignosulphonate is controlled by surface chemical reactions. Elemental sulfur is the main leaching product, which is mixed with iron-depleted sulfides and leads to the passivation of chalcopyrite. Electrochemical studies suggest that increasing the oxygen partial pressure leads to increasing the cathodic reaction rate and weakening the passivation of chalcopyrite.展开更多
An incubation experiment(Exp. 1) with three soils, two from Australia and one from Norway, was carried out to investigate the fate of dissolved BorreGro(a lignosulfonate, produced by Borregaard LignoTech Company, Norw...An incubation experiment(Exp. 1) with three soils, two from Australia and one from Norway, was carried out to investigate the fate of dissolved BorreGro(a lignosulfonate, produced by Borregaard LignoTech Company, Norway) at different concentrations(0, 10 and 100 mg C L-1) in soil solutions. A rhizobox experiment(Exp. 2) was also done in a Norwegian clay soil, mixed with four levels of BorreGro-carbon(BG-C) added(0, 2, 20 and 200 mg BG-C kg-1) to test the impact of BorreGro on root growth, rhizosphere chemistry(pH, metals and dissolved organic carbon(DOC)) and the composition of phospholipid fatty acids(PLFAs). The BorreGro addition increased the concentration of Mn due to the high concentrations in BorreGro. The BorreGro addition to soil had an indirect but significant impact on the rhizosphere chemistry and PLFAs. The lowest amounts of added BorreGro facilitated the DOC excretion at plant roots, and thereby increased the bacterial and fungal biomass, likely as an effect of increased Mn solubility from BorreGro in the root zone.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51574072,51434001)the Fundamental Research Funds for the Central Universities,China(No.2025028)。
文摘The pressure leaching mechanism of chalcopyrite was studied by both leaching tests and in-situ electrochemical measurements. The effects of leaching temperature, oxygen partial pressure, and calcium lignosulphonate, on copper extraction and iron extraction of chalcopyrite pressure leaching were investigated. The leaching rate is accelerated by increasing the leaching temperature from 120 to 150 ℃ and increasing oxygen partial pressure to 0.7 MPa. The release of iron is faster than that of copper due to the formation of iron-depleted sulfides. Under the optimal leaching conditions without calcium lignosulphonate, the copper and iron extraction rates are 79% and 81%, respectively. The leaching process is mixedly controlled by surface reaction and product layer diffusion with an activation energy of 36.61 k J/mol. Calcium lignosulphonate can effectively remove the sulfur passive layer, and the activation energy is 45.59 k J/mol, suggesting that the leaching process with calcium lignosulphonate is controlled by surface chemical reactions. Elemental sulfur is the main leaching product, which is mixed with iron-depleted sulfides and leads to the passivation of chalcopyrite. Electrochemical studies suggest that increasing the oxygen partial pressure leads to increasing the cathodic reaction rate and weakening the passivation of chalcopyrite.
基金Support by the Borregaard LignoTech Company,Norway
文摘An incubation experiment(Exp. 1) with three soils, two from Australia and one from Norway, was carried out to investigate the fate of dissolved BorreGro(a lignosulfonate, produced by Borregaard LignoTech Company, Norway) at different concentrations(0, 10 and 100 mg C L-1) in soil solutions. A rhizobox experiment(Exp. 2) was also done in a Norwegian clay soil, mixed with four levels of BorreGro-carbon(BG-C) added(0, 2, 20 and 200 mg BG-C kg-1) to test the impact of BorreGro on root growth, rhizosphere chemistry(pH, metals and dissolved organic carbon(DOC)) and the composition of phospholipid fatty acids(PLFAs). The BorreGro addition increased the concentration of Mn due to the high concentrations in BorreGro. The BorreGro addition to soil had an indirect but significant impact on the rhizosphere chemistry and PLFAs. The lowest amounts of added BorreGro facilitated the DOC excretion at plant roots, and thereby increased the bacterial and fungal biomass, likely as an effect of increased Mn solubility from BorreGro in the root zone.
