SO_2浸出软锰矿过程中抑制连二硫酸锰生成的研究

Study on Restrain Generation of Manganese Dithionate in Leaching of MnO_2 With SO_2

研究了用SO2浸出低品位软锰矿,考察了浸出过程中SO2流量、pH等工艺条件对产品质量的影响。试验结果表明,对液固体积质量比为3∶1的软锰矿矿浆而言,当SO2流量大于108mL/(min.L)后,产品中锰质量分数随SO2流量的增大而降低;SO2总物质的量与软锰矿中MnO2物质的量之比(α)可作为评价浸出体系氧化能力的指标,适宜的α为1.15;降低矿浆pH会促进镁等杂质的浸出,但随SO2流量增大,其抑制连二硫酸锰生成的作用增强;浓缩结晶阶段滴加硫酸降低pH至1.0,可有效提高产品中锰的质量分数。XRD分析结果表明,所制得的产品主要成分为MnSO4.H2O,晶形完好。TG-DSC分析结果表明,MnS2O6.2H2O的分解温度为230～500℃。

The leaching process of a low grade pyrolusite ore with SO2 was studied. The factors affecting Mn content in product, such as SO2 flow, slurry pH,were examined. The experimental results indicated that Mn content in product decreased with increasing of SO2 flow. When 802 flow exceeded 108 mL/（min L） for the pyrolusite slurry of liquid to solid of 3 ： 1,the radio （a） of total molar quantity of SO2 to MnO2 in pyrolusite ore could be used as a evaluation index for the system oxidation ability, and the appropriate a value was 1.15. Lower pH of pyrolusite slurry would enhance leaching of some impurities, such as Mg, however it would obviously restrain manganese dithionate generation when 802 flow exceeded 108 mL/（min L）. Using sulfuric acid to adjust solution pH to about 1.0 before concentrating and crystallizating manganese sulfate, Mn content in the product would be greatly increased. The product was mostly considered as MnSO4 H2O and had good crystallinity based on XRD. The thermal stability of the product was also analyzed by TG-DSC, the results showed that the decomposition temperature of MnS2O6 H2O was 230--500℃.