磷酸铵回流萃取工艺的研究

Study on the reflux extraction process of ammonium phosphate

使用溶剂回流萃取法净化湿法磷酸,改进传统湿法磷酸与溶剂萃取的方法,利用磷酸铵在萃取剂中溶解度低的特点,制取磷酸铵,以达到清洁、高效、低能耗生产的目的。实验考察了反应温度、萃取剂、相比(油相与水相的体积比)等因素对磷酸铵收率及纯度的影响。较佳的工艺条件:正丁醇为萃取剂,萃取的相比为2,反萃相比为2.8,洗涤净化相比为0.5,在此条件下磷酸铵最终收率≥89%,磷酸铵固体中杂质钙离子和氯离子的质量分数分别≤10%和≤6.5%。实验结果表明,溶剂回流萃取法较传统的磷酸铵生产工艺生产流程简单,耗能小,且副产物少,环境污染小,但各方面研究还仍处于实验室研究阶段。

Solvent reflux extraction method,which improved the traditional wet-process phosphoric acid and solvent extraction method,was applied to purify wet-process phosphoric acid.In this process,ammonium phosphate was produced by taking advantage of low solubility characteristic of ammonium phosphate in extracting agent,so as to achieve the goal of clean,high efficient,and low energy consumed production.Influences of reaction temperature,extracting agent,and phase ratio （ volume ratio of oil phase to water phase ） etc. on the yield and purity of ammonium phosphate were investigated. Optimum process conditions were as follows：normal butanol as extracting agent, extraction phase ratio was 2, reflux extraction phase ratio was 2.8, and washing and purifying phase ratio was 0.5. Under those conditions the final yeild of ammonium phosphate was more than 89% and impurity Ca^2＋ and Cl^- in solid product were less than 10% and 6.5% respectively. Experiment results showed that comparing with traditional ammonium phosphate production technology solvent reflux extration method had the advantages of simple production flow, low energy consumption, less by-products and environment pollution. However,all aspects of study were still in laboratory research stage.