The transformation behavior of ferrous sulfate was examined during hematite precipitation for iron removal in hydrometallurgical zinc.Specifically,the effects of the method used for oxygen supply(pre-crystallization o...The transformation behavior of ferrous sulfate was examined during hematite precipitation for iron removal in hydrometallurgical zinc.Specifically,the effects of the method used for oxygen supply(pre-crystallization or pre-oxidation of ferrous sulfate)and temperature(170–190℃)on the redissolution and oxidation–hydrolysis of ferrous sulfate were studied.The precipitation characteristics and phase characterization of the hematite product were investigated.The results showed that the solubility of ferrous sulfate was considerably lower at elevated temperatures.The dissolution behavior of ferrous sulfate crystals was influenced by both the concentrations of free acid and zinc sulfate and the oxydrolysis of ferrous ions.Rapid oxydrolysis of ferrous ions may serve as the dissolution driving force.Hematite precipitation proceeded via the following sequential steps:crystallization,redissolution,oxidation,and precipitation of ferrous sulfate.The dissolution of ferrous sulfate was slow,which helped to maintain a low supersaturation environment,thereby affording the production of high-grade hematite.展开更多
A simple comparative study of synergistic extraction of zinc from ammonium sulfate and ammonium chloride systems with mixtures of Mextral54-100 and tri-nalkylphosphine oxide(TRPO) dissolved in n-heptane was described....A simple comparative study of synergistic extraction of zinc from ammonium sulfate and ammonium chloride systems with mixtures of Mextral54-100 and tri-nalkylphosphine oxide(TRPO) dissolved in n-heptane was described. Various parameters affecting the extraction process were investigated. Experimental results show that extraction from ammonium sulfate is better than that from ammonium chloride under the same conditions owing to the additional complexation between zinc and chloride ions. Total ammonium concentration and pH have a significant effect on zinc extraction efficiency because of the formation of zinc ammine complexes. The synergistic effect is explained by the formation of adduct between zinc chelates and trialkylphosphine oxide. The thermodynamic data show that the extraction reaction is exothermic and stripping is endothermic. Infrared(IR) spectra of the zincloaded organic phases were also examined.展开更多
基金Projects(51804146,51964029,51664030,51564030)supported by the National Natural Science Foundation of ChinaProject(2018YFC1900402)supported by the National Key Research and Development Program of ChinaProject supported by the Analysis and Testing Center of Kunming University of Science and Technology,China
文摘The transformation behavior of ferrous sulfate was examined during hematite precipitation for iron removal in hydrometallurgical zinc.Specifically,the effects of the method used for oxygen supply(pre-crystallization or pre-oxidation of ferrous sulfate)and temperature(170–190℃)on the redissolution and oxidation–hydrolysis of ferrous sulfate were studied.The precipitation characteristics and phase characterization of the hematite product were investigated.The results showed that the solubility of ferrous sulfate was considerably lower at elevated temperatures.The dissolution behavior of ferrous sulfate crystals was influenced by both the concentrations of free acid and zinc sulfate and the oxydrolysis of ferrous ions.Rapid oxydrolysis of ferrous ions may serve as the dissolution driving force.Hematite precipitation proceeded via the following sequential steps:crystallization,redissolution,oxidation,and precipitation of ferrous sulfate.The dissolution of ferrous sulfate was slow,which helped to maintain a low supersaturation environment,thereby affording the production of high-grade hematite.
基金financially supported by the National Basic Research Program of China (No. 2014CB643404)the National Natural Science Foundation of China (Nos.51174104, 51304093, and 51364022)
文摘A simple comparative study of synergistic extraction of zinc from ammonium sulfate and ammonium chloride systems with mixtures of Mextral54-100 and tri-nalkylphosphine oxide(TRPO) dissolved in n-heptane was described. Various parameters affecting the extraction process were investigated. Experimental results show that extraction from ammonium sulfate is better than that from ammonium chloride under the same conditions owing to the additional complexation between zinc and chloride ions. Total ammonium concentration and pH have a significant effect on zinc extraction efficiency because of the formation of zinc ammine complexes. The synergistic effect is explained by the formation of adduct between zinc chelates and trialkylphosphine oxide. The thermodynamic data show that the extraction reaction is exothermic and stripping is endothermic. Infrared(IR) spectra of the zincloaded organic phases were also examined.
