湿法磷酸循环萃取无脱氟工艺研究

Purification of wet-process phosphoric acid by cycle extraction method in absence of fluorine-removal agent

研究了一条湿法磷酸循环萃取无脱氟工艺路线,不添加除氟剂,仅通过控制盐酸量即可得到氟质量分数较低的磷酸.实验结果表明：20 g磷矿粉中添加盐酸46 mL时实验结果最理想,此时循环过程中萃取液的磷氟比保持在230～300,且萃取率最高可达95％;为使实验过程简便可控,探讨了工艺路线的中控条件,结果表明控制每一步萃取液的pH为0.3～0.5即可得到较好的实验结果.

The purification of wet-process phosphoric acid is performed by cycle extraction method without addition of fluorine-removal agent. The phosphoric acid with low concentration of fluorine can be achieved only by controlling the concentration of hydrochloric acid. The results show that m（ P2O5 ）/m（F） in solution keeps around 230 -300 and the extraction rate is up to 95% under the following conditions：20 g of phosphate rock powder and 46 mL of hydrochloric acid. In order to make the experiment process simple and controllable, the optimization of process is explored. The result shows that controlling the pH around 0. 3 -0. 5 in each step can lead to the good experimental results.