高钙低品位钾矿卤水的钾盐生产技术研究

Research on the technique of recover potash from high calcium and low potassium containing brine

通过相图分析、自然蒸发结晶实验和盐析提钾实验等方式对氯化型含钙盐湖晶间卤水生产钾肥的技术进行了研究,结果表明:水合氯化钙、溢晶石、钾钙石等含钙固体盐不会在钾肥生产过程中析出;含钙卤水相图分析得到的钾盐提取率可达85.6%,含盐量为20.1%,但实际蒸发实验钾收率为72.9%,盐析提钾实验钾盐收率为77.6%。造成钾盐收率低于理论计算值的原因,一是含钙卤水的钾质量分数高于无钙卤水,使得钾盐提取率降低;二是自然蒸发结晶过程的过饱和现象使钾盐析出不充分。

The Technique of recover potash from high calcium and low potassium containing intercrystalline brines in part area of Chaerhan salt-lake were studied via phase diagram analysis, natu- ral evaporation,and salting-out method. The result show ： the cal- cium containing salt e. g. calcium chloride hydrate, tachyhydrite and potassium-calcium chloride double salt could not precipitate during the potash recovering process; potassium recover rate cal- culated basing phase diagram was 85. 6%, but the true recover rate was 72.9% by natural evaporation method and was 77.6% bysalting-out method, the NaCl content was corresponding to be 20.1% ; the lower recover ratio were caused by two reasons： the high concentration of calcium result in the high contained of potas- sium in the waste liquid, and potassium salt was unable to crystal- lize completely since the metastable phenomenon happened in the natural evaporation process.