多步法制备高纯磷酸二氢钾的工艺研究

Study on the Preparation of High-purity Potassium Dihydrogen Phosphate by Multi-step Method

采用自然沉降法,通过向湿法磷酸中投入沉降剂制得磷酸原料,随后与碳酰胺进行反应,经分离、过滤合成膦酸脲,其与钾源反应制得高纯磷酸二氢钾。通过考察磷酸脲含量、反应温度、氢氧化钾的量及结晶温度对产率及纯度的影响,得到了最佳制备工艺,目标产物磷酸二氢钾纯度高(w≥99.8%)、产率高(99.1%)。与传统制备方法相比,多步法具有工艺路线短、能耗低、产品质量稳定、生产成本低、操作方便等优点。

A natural precipitation method was adopted by adding precipitator into wet-process phosphoric acid to produce phosphoric acid raw material,which subsequently reacted with carbamide,and urea phosphate was obtained after separation and filtration.Finally,the high-grade potassium dihydrogen phosphate was obtained via the reaction of urea phosphate and potassium source.The optimum preparing process was obtained by exploring the influence factors of urea phosphate content,reaction temperature,potassium hydroxide content and crystallization temperature on yield and purity of potassium dihydrogen phosphate,which had high purity(w≥99.8%)and high yield(99.1%).Compared with traditional preparation methods,the multi-step method has the advantages of short process route,low energy consumption,stable product quality,low production cost and convenient operation.