Theextraction of manganese from low-grade manganese oxide ores using CaS derived from CaSO4 as reductant was investigated. The effects of mass ratio of CaS to ore, reduction temperature, reduction time, liquid to solid ratio (L/S ratio), stirring speed, leaching temperature, leaching time and H2SO4 concentration on the leaching rates of Mn and Fe during the reduction–acid leaching process were discussed. The leaching rates of 96.47% for Mn and 19.24% for Fe were obtained under the optimized conditions of mass ratio of CaS to manganese oxide ore 1:6.7, L/S ratio 5:1, stirring speed 300 r/min, reduction temperature of 95 °C for 2.0 h in the reduction process and leaching stirring speed of 200 r/min, H2SO4 concentration of 1.5 mol/L, leaching temperature of 80 °C for 5 min in the leaching process. In addition, this process can be employed in the recovery of manganese from various manganese oxide ores, and Mn leaching rate above 95% is obtained.%以CaSO4制备得到的CaS为还原剂,研究氧化锰矿的还原-酸浸过程,考察硫化钙与矿石的质量比、还原温度、还原时间、液固比、搅拌速率、浸出温度、浸出时间和H2SO4浓度对氧化锰矿中锰及铁浸出率的影响.结果表明:优化的还原工艺条件为硫化钙与矿石质量比1:6.7、液固比5:1、搅拌速率300 r/min、还原温度95 °C、还原时间2.0 h;酸浸工艺条件为搅拌速率200 r/min、H2SO4浓度1.5 mol/L、浸出温度80 °C、浸出时间5 min.在此优化条件下,锰的浸出率达到 96.47%,而铁的浸出率仅为 19.24%.该工艺可以应用于不同类型氧化锰矿中锰的提取,且锰的浸出率均高于95%.
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