磷酸二氢钙制备磷酸二氢钠磷收率研究

磷酸二氢钙是湿法磷酸精细加工的重要产品，开发以磷酸二氢钙为中间产物的精加工系列产品符合目前市场需求。研究了磷酸二氢钙与硫酸钠复分解反应制备磷酸二氢钠的工艺条件，并通过浓缩结晶得到磷酸二氢钠产品。对反应温度、物料配比、液固比以及反应时间诸因素对磷收率的影响进行了研究，确定了复分解过程适宜的工艺条件：反应温度为50 ℃，物料配比（硫酸钠与磷酸二氢钙物质的量比）为1.2∶1，液固比（质量比）为4∶1，反应时间为120 min。在此条件下磷收率可达79.1%。该工艺具产品纯度高、工艺流程简单、操作简便等优点。

Study on P2O5 recovery in production of sodium dihydrogen phosphate with calcium biphosphate

Calcium biphosphate is an important product in fine processing wet-process phosphoric acid(WPA),it conforms to the present market needing to develop the middle production of calcium biphosphate refined series product,and is of great significance.Process conditions of preparation of sodium dihydrogen phosphate with double decomposition reaction between calcium biphosphate and sodium sulfate were studied,and product by concentrated crystallization process was obtained.Influences of the reaction temperature,mix ratio of sodium sulfate to calcium biphosphate,ratio of liquid to solid,and reaction time on P2O5 recovery were investigated.Optimal process parameters of the reaction obtained were as follows:the reaction temperature was 50 ℃,mix ratio of sodium sulfate to calcium biphosphate was 1.2∶1,mass ratio of liquid to solid was 4∶1,and reaction time was 120 min.Under the conditions,the P2O5 recovery was 79.1%.Advantages of this process were the purity of product was high,process flow was short,and operation was simple etc.