硝酸磷肥生产除钙过程中钾携带问题研究

硝酸磷肥生产中采用硫酸钾除钙离子,可以生产氮磷钾三元复合肥,但是在生成石膏沉淀的过程中会有少量硫酸钾与硫酸钙生成复盐形式析出。研究了沉淀温度、浓度、硫酸钾加入量、硫酸钾加入方式等因素对钾携带的影响,当采用56%稀硝酸分解磷矿粉所得的酸解液,加入400 g硫酸钾/L水的悬浮液,沉淀温度100℃,钾石膏沉淀中的钾含量低于0.5%,总带出量小于1%,钾石膏生成量较大,钙离子沉淀完全。

Influence of decalcium on potassium loss in production of nitric phophate

NPK compound fertilizer was produced by adding potassium sulphate to decomposite slurry product of nitric phosphorite,but a small quantity of potassium sulphate was lost by coprecipitating with precipitaed gypsum phase.The effects of precipitating temperature,concentration,quantity of potassium sulphate addition and state of added potassium sulphate on potassium carrying was studied.When nitric acid(56% mass fraction)decomposing phophorite,the optimum reaction conditons were obtained:material mass ratio m(K2SO4) ∶m(H2O) was 0.4 ∶1,precitating temperature was 100 ℃,and K2O content in gypsum was under 0.5%,potassium loss was under 1%,and calcium was precipitated completed.