In order to illustrate the thermodynamic characteristics of arsenic during alkaline pressure oxidation leaching process oflead anode slime(NaNO3as oxidant;NaOH as alkaline reagent),theφ-pH diagrams of As-Na-H2O,N-H2O...In order to illustrate the thermodynamic characteristics of arsenic during alkaline pressure oxidation leaching process oflead anode slime(NaNO3as oxidant;NaOH as alkaline reagent),theφ-pH diagrams of As-Na-H2O,N-H2O,As-N-Na-H2Osystems at ionic mass concentration of0.1mol/kg and temperatures of298,373,423and473K were established according tothermodynamic calculation.The results show that the existence forms of arsenic are associated with pH value,which mainly exists inthe forms of H3AsO4,24H AsO-,24HAsO-,H2AsO2-and As2O3in lower pH region,while it mainly exists in the form of3AsO4-when pH>11.14.High alkali concentration and high temperature are advantageous to the arsenic leaching.The alkaline pressureoxidation leaching experiments display that the tendency of arsenic leaching rate confirms the thermodynamic analysis resultsobtained from theφ-pH diagrams of As-N-Na-H2O system,and the highest leaching rate of arsenic reaches95.85%at453K.展开更多
A new alkaline pressure oxidative leaching process(with NaNO3 as the oxidant and NaOH as the alkaline reagent)is proposed herein to remove arsenic,antimony,and lead from bismuth-rich and arsenic-rich lead anode slime ...A new alkaline pressure oxidative leaching process(with NaNO3 as the oxidant and NaOH as the alkaline reagent)is proposed herein to remove arsenic,antimony,and lead from bismuth-rich and arsenic-rich lead anode slime for bismuth,gold,and silver enrichment.The effects of the temperature,liquid-to-solid ratio,leaching time,and reagent concentration on the leaching ratios of arsenic,antimony,and lead were investigated to identify the optimum leaching conditions.The experimental results under optimized conditions indicate that the average leaching ratios of arsenic,antimony and lead are 95.36%,79.98%,63.08%,respectively.X-ray diffraction analysis indicated that the leaching residue is composed of Bi,Bi2O3,Pb2Sb2O7,and trace amounts of NaSb(OH)6.Arsenic,antimony,and lead are thus separated from lead anode slime as Na3AsO4·10H2O and Pb2Sb2O7.Scanning electron microscopy and energy-dispersive spectrometry imaging revealed that the samples undergo appreciable changes in their surface morphology during leaching and that the majority of arsenic,lead,and antimony is removed.X-ray photoelectron spectroscopy was used to demonstrate the variation in the valence states of the arsenic,lead,and antimony.The Pb(IV)and Sb(V)content was found to increase substantially with the addition of NaNO3.展开更多
Fe^(2+)dissolution method and manual method were used to remove the anode slime and their effects on properties of cast Pb−0.6wt.%Ag anode and zinc electrowinning were compared.The results reveal that the Fe^(2+)disso...Fe^(2+)dissolution method and manual method were used to remove the anode slime and their effects on properties of cast Pb−0.6wt.%Ag anode and zinc electrowinning were compared.The results reveal that the Fe^(2+)dissolution method can avoid mechanical damage to the oxide film layer on the anode surface,which cannot be achieved by traditional manual method.This can lower the anode corrosion rate by 57.14%,thus reducing Pb contamination in electrolyte and zinc products.Meanwhile,compared with manual method,Fe^(2+)dissolution method can significantly improve the electrocatalytic activity of the anode and lower the initial power consumption of zinc electrowinning to 2720 kW·h/t after removing anode slime.展开更多
基金Project(51564031) supported by the National Natural Science Foundation of ChinaProject(0201352042) supported by the Cooperation between School and Enterprise of China
文摘In order to illustrate the thermodynamic characteristics of arsenic during alkaline pressure oxidation leaching process oflead anode slime(NaNO3as oxidant;NaOH as alkaline reagent),theφ-pH diagrams of As-Na-H2O,N-H2O,As-N-Na-H2Osystems at ionic mass concentration of0.1mol/kg and temperatures of298,373,423and473K were established according tothermodynamic calculation.The results show that the existence forms of arsenic are associated with pH value,which mainly exists inthe forms of H3AsO4,24H AsO-,24HAsO-,H2AsO2-and As2O3in lower pH region,while it mainly exists in the form of3AsO4-when pH>11.14.High alkali concentration and high temperature are advantageous to the arsenic leaching.The alkaline pressureoxidation leaching experiments display that the tendency of arsenic leaching rate confirms the thermodynamic analysis resultsobtained from theφ-pH diagrams of As-N-Na-H2O system,and the highest leaching rate of arsenic reaches95.85%at453K.
基金financially supported by the National Natural Science Foundation of China(No.51564031)Independent Research Project of the State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUTS1707)the Cooperation project between School and Enterprise of China(No.0201352042)
文摘A new alkaline pressure oxidative leaching process(with NaNO3 as the oxidant and NaOH as the alkaline reagent)is proposed herein to remove arsenic,antimony,and lead from bismuth-rich and arsenic-rich lead anode slime for bismuth,gold,and silver enrichment.The effects of the temperature,liquid-to-solid ratio,leaching time,and reagent concentration on the leaching ratios of arsenic,antimony,and lead were investigated to identify the optimum leaching conditions.The experimental results under optimized conditions indicate that the average leaching ratios of arsenic,antimony and lead are 95.36%,79.98%,63.08%,respectively.X-ray diffraction analysis indicated that the leaching residue is composed of Bi,Bi2O3,Pb2Sb2O7,and trace amounts of NaSb(OH)6.Arsenic,antimony,and lead are thus separated from lead anode slime as Na3AsO4·10H2O and Pb2Sb2O7.Scanning electron microscopy and energy-dispersive spectrometry imaging revealed that the samples undergo appreciable changes in their surface morphology during leaching and that the majority of arsenic,lead,and antimony is removed.X-ray photoelectron spectroscopy was used to demonstrate the variation in the valence states of the arsenic,lead,and antimony.The Pb(IV)and Sb(V)content was found to increase substantially with the addition of NaNO3.
基金supported by Zhejiang Libo Industrial Co.,Ltd.,Shaoxing,China。
文摘Fe^(2+)dissolution method and manual method were used to remove the anode slime and their effects on properties of cast Pb−0.6wt.%Ag anode and zinc electrowinning were compared.The results reveal that the Fe^(2+)dissolution method can avoid mechanical damage to the oxide film layer on the anode surface,which cannot be achieved by traditional manual method.This can lower the anode corrosion rate by 57.14%,thus reducing Pb contamination in electrolyte and zinc products.Meanwhile,compared with manual method,Fe^(2+)dissolution method can significantly improve the electrocatalytic activity of the anode and lower the initial power consumption of zinc electrowinning to 2720 kW·h/t after removing anode slime.
