湿法磷酸净化酸的提纯工艺研究

Study on purification of purified wet-process phosphoric acid

研究了以工业级湿法磷酸净化酸为原料,采用间歇式冷却结晶的方式,制备出食品级及高纯磷酸晶体。通过实验主要考察了搅拌速率、降温速率、助长剂用量、养晶时间对磷酸结晶提纯的影响,确定了最佳工艺条件：搅拌转速为400 r/min、降温速率为4℃/h、助长剂用量为0.15%~0.2%、养晶时间为1.5 h。在最佳工艺条件下,制备出的产品达到了GB 3149—2004《食品添加剂磷酸》食品级磷酸及以上的质量要求,并且产品附加值高。该方法为工业级湿法磷酸净化酸生产高品质磷酸提供了一条可行的途径。

Food grade and high purity phosphoric acid crystals were prepared by batch cooling crystallization with industrial grade purified wet-process phosphoric acid as raw material.The influences of stirring rate,cooling rate,growth substance dosage,and crystallization time on the purification effect of phosphoric acid crystallization were investigated,and the optimum conditions were confirmed as follows： stirring speed of 400 r/min,cooling rate of 4 ℃/h,growth substance dosage of 0.15%~0.2%,and crystallization time of 1.5 h.Under the optimum conditions,the prepared products reached the quality requirements of food grade and above,stipulated in the Standard of Food Additive Phosphoric Acid（GB 3149—2004）,and their added value was higher.The method provides a new way for the industrial production of high-quality phosphoric acid by purification of wet process phosphoric acid.