脱除硫酸锰溶液中杂质镁的研究

分别采用重结晶法和氟化沉淀法脱除硫酸锰溶液中的杂质镁。用Pitzer热力学模型对二元系MgSO4-H2O、MnSO4-H2O和三元系MgSO4-MnSO4-H2O的溶解度相图进行模拟预测,并结合溶解度相图对三元系的固溶体用重结晶法验证其分配比。同时采用氟化沉淀法进行对比试验。结果表明,由于固定分配比,重结晶法对镁锰分离作用十分有限,而加入MgF2晶种的氟化沉淀除镁新方法能够有效提高氟化沉淀法的效率,在95℃下,加入0.3g氟化镁晶种和250%理论用量的NH4F搅拌1h,能使镁的除去率达到94.3%。

Study on Magnesium Removal in Manganese Sulfate Solution

Magnesium impurity was removed by recrystallization and fluoride precipitation in manganese sulfate solution,respectively.The solubility isotherms of binary systems MgSO4-H2O,MnSO4-H2O and ternary system MgSO4-MnSO4-H2O were simulated and predicted with Pitzer thermodynamic model,and the distribution ratio of MgSO4 and MnSO4 in solid phase-liquid phase was verified via recrystallization experiment.Magnesium was also removed by fluoride precipitation compared with the former.The results show that recrystallization exerts quite limited effect on the separation of Mg and Mn by recrystallization due to constant distribution ratio,and the efficiency is improved by adding MgF2 crystal seed in fluorination.The removal rate of Mg is 94.3% at 95 ℃ with 0.3 g MgF2 and 250% NH4F for 1 h.