利用磷化渣制备电池级磷酸铁

Preparation of battery grade iron phosphate from phosphating slag

以含锌磷化渣为原料,先用氢氧化钠浸取制得磷酸钠溶液,再采用萃取法去除该溶液中的微量锌,在净化液中加入六水合氯化铁反应制得磷酸铁产品。实验结果表明:采用氢氧化钠浸取磷化渣,能有效地去除磷化渣中的金属离子,获得含微量锌的磷酸钠溶液,磷酸根的浸取率可达93.97%,磷酸根的总利用率可达78.31%;采用双硫腙与P204萃取剂对该溶液进行萃取,其双萃取剂混合萃锌效果明显优于它们相应的单种萃取剂萃锌效果。在有机相与水相体积比=1∶5时,锌的单级萃取率可达55.39%,产品磷酸铁中锌含量低于30.0μg/g。研究表明,采用氢氧化钠浸取和双硫腙与P204双萃取剂除杂的方法,可有效回收含锌磷化渣中的磷酸根并制备出电池级磷酸铁。

Using zinc-containing phosphating slag as raw material,firstly use NaOH leaching to obtain Na3PO4 solution,then remove the trace amount of zinc in the solution by extraction method and add FeCl3·6H2O to the purified liquid to obtain iron phosphate product.The experimental results showed that NaOH leaching can effectively remove the metal ions in the phosphat ing slag and then obtain the Na3PO4 solution containing a trace amount of zinc.The leaching rate of the phosphate can reach93.97%and the total utilization rate can reach 78.31%.The dithizone and P204 extractants were used to extract the solution.The zinc extraction effect of double extractant was significantly better than their corresponding single extractant effect.When O∶A=1∶5,the extraction rate of zinc was up to 55.39%and the content of zinc in the product iron phosphate was less than30.0μg/g.Research showed that the use of NaOH leaching and dithizone and P204 double extractant impurity removal method can effectively recover the phosphate in the zinc-containing phosphating slag and prepare battery-grade iron phosphate.