硫化铅还原硫酸浸出锌电解阳极泥中二氧化锰的试验研究

Sulphuric Acid Leaching of MnO_2 from Zinc Electrolysis Anode Slime Using PbS as a Reductant

对株冶电解锌阳极泥开展了用PbS做还原剂硫酸还原浸出二氧化锰的试验研究,纯PbS矿物样还原浸出试验考察了PbS颗粒细度、PbS与MnO2摩尔比、硫酸与MnO2摩尔比、浸出反应温度、浸出反应时间等因素对锰浸出率的影响,试验结果表明,PbS颗粒越细,与MnO2接触的表面积就越大,锰浸出速度就越快;PbS与MnO2摩尔比、硫酸与MnO2摩尔比、浸出反应温度、浸出反应时间等对锰的浸出速度有很大影响,在采用0.037～0.074mm的纯PbS条件下,试验获得的最佳浸出条件是PbS∶MnO2摩尔比>0.5,H2SO4∶MnO2摩尔比3,浸出反应温度90℃,时间2h.在较佳条件下用0.037～0.074mm纯方铅矿样做还原剂可获得锰浸出率85%以上的试验指标,在同样条件下用实际硫化铅浮选精矿样做还原剂可获得锰浸出率93%以上的试验指标.实际PbS浮选精矿样还原浸出试验表明ZnS和FeS2等其它硫化矿物对二氧化锰存在协同还原浸出作用,协同还原浸出作用造成浸出液含杂升高,浸出渣中铅含量降低.因此,如果需要利用含Mn2+浸出液制备高纯的锰产品,同时为了便于浸出渣配料入炉冶炼,宜采用品位较高的PbS浮选精矿样做还原剂.

An investigation into leaching of MnO2 from zinc electrolysis anode slime in Zhuzhou Zinc smelter in sulphuric acid solution using PbS as a reductant was carried out. The effects of the fineness of PbS particle, the molar ratio of PbS to MnO2, the molar ratio of H2SO4 to MnO2, the reaction time and temperature etc. on the leaching rate of Mn were discussed in the batch test that used pure PbS as the reductante. The results revealed that the finer the PbS particles were, the more contact area of PbS particles to MnO2 was, and so the faster the leaching speed of Mn was obtained. The results also showed that the molar ratio of PbS to MnO2, the molar ratio of H2SO4 to MnO2, the reaction time and temperature etc. had significant influence on the leaching speed of Mn. The optimal leaching conditions were obtained using 0.5 molar ratio of PbS to MnO2 and 3 molar ratio of H2SO4 to MnO2 for 120min at 90℃. At the optimal leaching conditions using 0.037-0.074mm pure PbS as the reductant, more than 85% of Mn leaching rate could be obtained. At the same conditions using PbS flotation concentrates as the reductant, more than 93% of Mn leaching rate could be obtained. The leaching test using PbS flotation concentrate as the reductant showed that the synergistic reductive extraction of ZnS and FeS caused the content of impurities in filtrate be upgraded, as well as the content of Pb in leaching slag be reduced. So that, in order to produce high-purity manganese products using Mn^2＋-containing leaching solution, as well as to facilitate leaching slag into the furnace smelting, it is better to adopt a higher grade flotation concentrate of PbS as the reductant.