低品位碳酸锰矿制备高纯度硫酸锰工艺研究

利用低品位碳酸锰矿和硫酸浸出反应，经除杂净化制备了高纯度硫酸锰。在液固比为5∶1、硫酸浓度为0.86 mol/L、搅拌速度为300 r/min、反应时间为80 min的条件下，对锰矿浸出过程做了动力学研究。结果表明，该锰矿浸出过程基本符合由内扩散控制的未反应收缩核模型，经计算得到表观活化能Ea=9.83 kJ/mol。对70 ℃下锰浸出率为91.4%的浸出液做了除杂净化处理。在80 ℃条件下，先加入用量为理论值1.5倍的二氧化锰将Fe2+氧化成Fe3+，再控制pH为5.0进行水解除铁，除铁率为96.38%，且除铁过程中锰损失率仅为4.98%。用S.D.D除重金属时，控制溶液温度约为60 ℃、pH为5.4~6.0、S.D.D加入量为理论值的1.2倍、反应时间为60 min，得到溶液中残留镍质量分数≤1.5×10-6，除镍率达95.3%。最后采用中温条件下蒸浓结晶法制备得到MnSO4·H2O质量分数为98%的硫酸锰产品。

Study on technology of preparing high purity manganese sulfate with low-grade manganese carbonate ores

By using low grade manganese carbonate ores to react with sulfuric acid，high purity manganese sulfate was pepared after purifying the leaching solution.Under the conditions of liquid to solid ratio of 5∶1，sulfuric acid concentration of 0.86 mol/L，agitation rate of 300 r/min，and reaction time of 80 min，the kinetics of leaching manganese was investigated.Results showed，the leaching process mainly followed the internal diffusion-controlled shrinking core model，and the apparent activation energy（Ea） was calculated to be 9.83 kJ/mol.Then，the leaching solution，which was obained by extracting 91.4%from mangnese ores at 70 ℃，was subjected to purification treatment.Firstly，adding manganese dioxide with dosage of 1.5 times of the theoretical value to the lixivium at 80 ℃，and Fe2+ was oxidized to Fe3+.Then Fe3+ was removed through hydrolysis. At the pH of 5.0，the iron-removal efficiency was 96.38%，and the loss ratio of manganese in iron-removal was merely 4.98%. Sodium dimethyl dithio carbamate（S.D.D） was used to precipitate the heavy metals.Under the conditions of that thetemperature was about 60 ℃，the pH was 5.4~6.0，and the dosage of S.D.D was 1.2 times of the theoretical value，the retained Ni2+ content in the purified solution could reach less than 1.5×10-6 and the efficiency of removing Ni2+ was 95.3%. Finally，evaporation-concentration-crystallization method was carried out under the conditions of middle-temperature，purity of manganese sulfate product could reach 98%.