磷酸二氢钙制备磷酸二氢钾过程研究

Preparation of Potassium Dihydrogen Phosphate From Calcium Dihydrogen Phosphate

采用普钙或重钙与硫酸钾反应制取KH_2PO_4,原料成本低、工艺简单,是具有一定工业应用前景的KH_2PO_4生产新工艺。本文通过对Ca(H_2PO_4)_2与硫酸钾反应制备KH_2PO_4的工艺过程进行研究,在最佳工艺条件:反应温度为70℃,K/P摩尔比1.1,反应时间为2 h,液固比5∶1,获得磷收率84.2%,钾收率95.1%。产品及滤渣XRD分析表明,产品为纯度高的KH_2PO_4,滤渣主要成分为半水硫酸钙和磷酸氢钙,钾损失较小,但磷的损失较大。

The preparation process of potassium dihydrogen phosphate from calcium superphosphate or ground calcium carbonate and potassium sulfate has the advantages of cheap raw materials and simple process flow,so it has a certain application prospect.In this paper,the preparation process of potassium dihydrogen phosphate from Ca（H2PO4）2 and potassium sulfate was studied.The best process conditions including reaction temperature,reaction time,material ratio and liquid-solid ratio were investigated.The results showed that,under the best condition of 70 ℃,K2O/P2O5 molar ratio 1.1,2 h,liquid to solid ratio 5： 1,the phosphorus yield was up to 84.2%,the potassium yield was up to 95.1%.The XRD analysis of product and residue indicated that the product was pure potassium dihydrogen phosphate,main components of the residue were hemihydrate calcium sulfate and calcium hydrogen phosphate,potassium loss was small but the loss of phosphorus was larger.