废旧电池回收过程中磷酸铁渣的提纯

Purification of Iron Phosphate Waste GeneratedAfter Recycling of Spent Batteries

为实现磷酸铁渣高附加值资源回收利用,采用盐酸浸出渣中铁、铁粉置换除铜、水解-化学沉淀法去除浸出液中钛、铝。结果表明,盐酸浓度25%、液固比6 mL/g、浸出温度60℃、浸出时间60 min时,磷酸铁渣中铁浸出率达98.7%;控制溶液初始pH=0.6,铁粉添加量为浸出液中铁物质的量0.55倍、反应温度60℃、反应时间35 min时,铜去除率达96.2%,钛去除率达83.6%;水解-化学沉淀法除钛、铝的过程中,氟化钠与铝物质的量比8∶1、反应pH=1.9、反应温度40℃、反应时间30 min时,钛去除率达97.6%,铝去除率达99.3%,浸出液中杂质元素含量满足后续电池级磷酸铁的制备要求。

In order to recover and utilize high value⁃added iron phosphate waste,an experimental study was carried out by adopting a process consisting of hydrochloric acid leaching,replacement of iron powder for copper removal,and hydrolyzation and chemical precipitation for removal of titanium and aluminum therein.The results show that after 1 h leaching at 60℃with hydrochloric acid concentration of 25%,liquid⁃solid ratio of 6 mL/g,the leaching rate of iron can be up to 98.7%.And then after 35 min reaction at 60℃with the initial pH of the solution controlled at 0.6,the addition of iron powder at an amount of 0.55 times of the molar number of iron in the leaching solution,the removal rate of copper and titanium can reach 96.2%and 83.6%respectively.By the following process of hydrolyzation and chemical precipitation with sodium fluoride 8 times of the molar number of aluminum,the removal rate of titanium and aluminum can reach 97.6%and 99.3%after 30 min reaction at 40℃with pH of 1.9.It is shown that the content of impurities in the leaching solution meets the requirements for the subsequent synthesis of iron phosphate for batteries.