碳酸锰热解—酸洗制备高纯化学二氧化锰试验研究

Preparation of High Pure Manganese Dioxide by Pyrolysis-Acid Washing of Manganese Carbonate

研究了以软锰矿脱硫吸收液碳化所得碳酸锰为原料,通过热解—酸洗工艺制备高纯化学二氧化锰,考察了热解过程中热解温度、空气流量和热解时间对碳酸锰中锰元素形态转化及酸洗过程中洗涤温度、搅拌速度和硝酸浓度对焙烧产物中锰洗出量的影响。结果表明:在热解温度450℃、空气流量0.4m^3/h、热解时间11h条件下,碳酸锰热解产物中四价锰占比达54.92%;将热解产物在反应温度80℃、搅拌速度300r/min条件下,用浓度为0.14mol/L的硝酸溶液洗涤,产物中MnO2质量分数可达95.79%。

The high-pure manganese dioxide was prepared by pyrolysis-acid washing process using manganese carbonate as raw material for carbonization of pyrolusite desulfurization absorption solution.The effects of pyrolysis temperature,air flow rate and pyrolysis time on the transformation of manganese in manganese carbonate and the effects of washing temperature,stirring speed and nitric acid concentration on manganese eluted amount in the calcined product were examined.The results show that the mass fraction of tetravalent manganese in the pyrolysis product of manganese carbonate reaches 54.92% under the conditions of reaction temperature of 450 ℃,air flow rate of 0.4 m^3 /h and pyrolysis time of 11 h.The pyrolysis product is washed at the temperature of 80 ℃,rotation speed of 300 r/min and nitric acid concentration of 0.14 mol/L,and the MnO 2 content in the product is 95.79%.