Preparation Of Battery-level Manganese Sulfate From Electrolytic Zinc Anode Slimes

Electrolytic zinc anode slimes are by-product of the production of electrolytic zinc,the Mn content of which is during40to50percents.And it contains elements such as Pb、Ag and so on.But there are very few study reports on the recycle of zinc anode slimes.This paper reports that the study of the leaching of zinc anode slimes in the presence of PbS and H2SO4based on the study of the the leaching of manganese ore, so as to separate Mn and Pb of it. And the leaching liquid was purificated and crystallized in addition to preparate of battery-level high purity manganese sulfate. The main content of the paper and the results are as follows:(1) The best experiment condition of this leaching Zn anode slimes in PbS-H2SO4-H2O system was as follow:the stirring speed of400r/min, liquid-solid ratio was2:1,m(zinc anode slimes):m(H2SO4):m(PbS)=1:3.16:1.13,the temperature was90℃, the reaction time was2h, and the leaching rate of Mn was more than90%.(2) The leaching liquid was purificated. The jarosite process was used to remove impurities K+and Na+, the best experiment condition was as follows:the dosage coefficient of Fe2(SO4)3was1.1,the solution pH was2.5,the temperature was90℃, the reaction time was2h.Fe3+and Al3+in leaching solution were removed in the neutralizing hydrolysis by using MnCO3as neutralizer. When the solution pH was5.2±0.2,they could be almost all removed. MDD was used to remove impurities heavy metal ions. The best experiment condition was as follows:the system pH is5.2,the dosage of MDD was8g/L, the temperature was80℃, the reaction time was2.5h.Ca2+and Mg2+were removed by using TMC. the best experiment condition was as follows:the dosage coefficient of TMC was1.2, the solution pH was5.2,the temperature was85℃, the reaction time was2h. The purified leaching solution reached the follow-up process requirement.(3) The coagulant sedimentation method was used to remove F-in the purified leaching solution, and Al2(SO4)3was selected as coagulation precipitation agent. The best experiment condition was as follows: m(Al/F)=2.5, the temperature was50℃, the system pH was5.9,the reaction time was120min at the speed of200r/min. Fluorine content could be decreased from317.5mg/L to85mg/L.Finally,the pure MnSO4solution was concentrated and crystallized in preparation of MnSO4solid, and the products reached the standard of battery-level high purity manganese sulfate.