复盐沉淀法制备磷酸铵盐的工艺条件研究

针对中低品位磷矿开发应用所存在的不足,以贫磷矿为原料,采用盐酸-复盐沉淀法制备磷酸铵盐,并着重考察磷酸三聚氰胺复盐沉淀工序较适宜的工艺条件。以溶液中磷酸的沉淀率为主要考察指标,通过单因素实验和正交实验考察并确定较适宜的工艺条件为:反应温度为70℃、磷酸溶液c(H_3PO_4)为0.6 mol/L、三聚氰胺与磷酸物质的量之比为1.5、反应时间为1.5 h,此条件下的3次重复实验结果显示磷酸的平均沉淀率为98.27%。所制备的复盐沉淀样品经XRD分析及红外光谱表征,主要成分为磷酸三聚氰胺复盐。

Study on process conditions of ammonium phosphate preparation with complex salt precipitation method

For the deficiency of the development of phosphate ore with middle and low grade, hydrochloric acid-complex salt precipitation method is adopted to prepare ammonium phosphate from lean phosphate ore. The precipitation process of melamine phosphate complex salt is determined and the technological conditions are optimized. Taking the precipitation rate of phosphoric acid in solution as the main index, the technological conditions are investigated and optimized by single-factor and orthogonal experiments as follows: reaction temperature is 70 ℃, the concentration of phosphoric acid solution is 0.6 mol/L, the ratio of amount of substance of melamine to phosphoric acid is 1.5,and the reaction time is 1.5 h. The results of three repeated experiments under the optimum condition show that the average precipitation rate of phosphoric acid can reach to 98.27%. The sample of complex salt precipitation is analyzed by XRD and FT?IR, it is pointed that the main components is crystallization of melamine phosphate.