Lead extraction from spent lead–acid battery paste in a molten Na2CO3 salt containing Zn O as a sulfur-fixing agent was studied. Some influencing factors, including smelting temperature, reaction time, Zn O and salt ...Lead extraction from spent lead–acid battery paste in a molten Na2CO3 salt containing Zn O as a sulfur-fixing agent was studied. Some influencing factors, including smelting temperature, reaction time, Zn O and salt dosages, were investigated in detail using single-factor experiments. The optimum conditions were determined as follows: T = 880°C; t = 60 min; Na2CO3/paste mass ratio = 2.8:1; and the Zn O dosage is equal to the stoichiometric requirement. Under the optimum conditions, the direct recovery rate of lead reached 98.14%. The results suggested that increases in temperature and salt dosage improved the direct recovery rate of lead. XRD results and thermodynamic calculations indicated that the reaction approaches of lead and sulfur were Pb SO4→Pb and Pb SO4→Zn S, respectively. Sulfur was fixed in the form of Zn S, whereas the molten salt did not react with other components, serving only as a reaction medium.展开更多
A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that...A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd, Cu, Fe and Zn in slag reach 88.3%, 54.1%, 69.6% and 54.7%, respectively, while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L, 65 ℃ and 120 r/min for 2 h. However, Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd, Cu, Fe, Pb and Zn from zinc smelting slag.展开更多
Lift cycle assessment(LCA)methodology was applied to evaluating and comparing two waste acid disposal processes in zinc smelting.The results indicate that environmental impacts of gas−liquid vulcanization technologies...Lift cycle assessment(LCA)methodology was applied to evaluating and comparing two waste acid disposal processes in zinc smelting.The results indicate that environmental impacts of gas−liquid vulcanization technologies are human toxicity,abiotic depletion potential,and global warming risk,which are mainly caused in neutralizing−evaporating−crystallization unit and electrodialysis unit.As for traditional lime neutralization method,vulcanization unit is the main factor.In this regard,the total environmental impact of traditional lime neutralization method is much higher than that of gas−liquid vulcanization technologies.Furthermore,the sensitive analysis shows that electricity and sodium sulfide(60%)are sensitive factors in two waste acid disposal technologies.In addition,the total cost of disposing a functional unit waste acid in traditional lime neutralization process is nearly 27 times that of the gas−liquid vulcanization waste acid disposal technologies.展开更多
基金financially supported by the National Nature Science Foundation of China (Nos. 51234009 and 51104182)the Natural Science Foundation of Hunan Province, China (No. 13JJ5035)the Scientific Research Fund of Hunan Provincial Education Department, China (No. 14C0349)
文摘Lead extraction from spent lead–acid battery paste in a molten Na2CO3 salt containing Zn O as a sulfur-fixing agent was studied. Some influencing factors, including smelting temperature, reaction time, Zn O and salt dosages, were investigated in detail using single-factor experiments. The optimum conditions were determined as follows: T = 880°C; t = 60 min; Na2CO3/paste mass ratio = 2.8:1; and the Zn O dosage is equal to the stoichiometric requirement. Under the optimum conditions, the direct recovery rate of lead reached 98.14%. The results suggested that increases in temperature and salt dosage improved the direct recovery rate of lead. XRD results and thermodynamic calculations indicated that the reaction approaches of lead and sulfur were Pb SO4→Pb and Pb SO4→Zn S, respectively. Sulfur was fixed in the form of Zn S, whereas the molten salt did not react with other components, serving only as a reaction medium.
基金Project(2011SK3262) supported by Science and Technology Program of Hunan Province,China
文摘A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd, Cu, Fe and Zn in slag reach 88.3%, 54.1%, 69.6% and 54.7%, respectively, while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L, 65 ℃ and 120 r/min for 2 h. However, Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd, Cu, Fe, Pb and Zn from zinc smelting slag.
基金the National Key R&D Program of China(Nos.2018YFC1903304,2019YFC1907405)National Natural Science Foundation of China(No.51904354).
文摘Lift cycle assessment(LCA)methodology was applied to evaluating and comparing two waste acid disposal processes in zinc smelting.The results indicate that environmental impacts of gas−liquid vulcanization technologies are human toxicity,abiotic depletion potential,and global warming risk,which are mainly caused in neutralizing−evaporating−crystallization unit and electrodialysis unit.As for traditional lime neutralization method,vulcanization unit is the main factor.In this regard,the total environmental impact of traditional lime neutralization method is much higher than that of gas−liquid vulcanization technologies.Furthermore,the sensitive analysis shows that electricity and sodium sulfide(60%)are sensitive factors in two waste acid disposal technologies.In addition,the total cost of disposing a functional unit waste acid in traditional lime neutralization process is nearly 27 times that of the gas−liquid vulcanization waste acid disposal technologies.
