Process for recycle of spent lithium iron phosphate battery via a selective leaching-precipitation method

选择性浸出-沉淀法回收废磷酸铁锂电池

Applying spent lithium iron phosphate battery as raw material,valuable metals in spent lithium ion battery were effectively recovered through separation of active material,selective leaching,and stepwise chemical precipitation.Using stoichiometric Na2S2O8 as an oxidant and adding low-concentration H2SO4 as a leaching agent was proposed.This route was totally different from the conventional methods of dissolving all of the elements into solution by using excess mineral acid.When experiments were done under optimal conditions(Na2S2O8-to-Li molar ratio 0.45,0.30 mol/L H2SO4,60℃,1.5 h),leaching efficiencies of 97.53% for Li^+,1.39%for Fe^3+,and 2.58% for PO4^3−were recorded.FePO4 was then recovered by a precipitation method from the leachate while maintaining the pH at 2.0.The mother liquor was concentrated and maintained at a temperature of approximately 100℃,and then a saturated sodium carbonate solution was added to precipitate Li2CO3.The lithium recovery yield was close to 80%.

以废磷酸铁锂电池为原料,通过活性物质分离、选择性浸出、逐步化学沉淀等工序回收废旧锂离子电池中的有价金属。提出了使用化学计量比的Na2S2O8作为氧化剂并添加低浓度H2SO4作为浸出剂进行实验。该方法与传统上使用过量无机酸将所有元素溶解到溶液中的常规方法完全不同。在最佳条件下进行实验下(Na2S2O8和Li的摩尔比0.45;0.30 mol/L H2SO4;60℃;1.5 h),记录Li^+的浸出效率为97.53%,Fe^3+的浸出效率为1.39%,PO4^3−的浸出效率为2.58%。然后通过控制pH为2.0使用沉淀法从浸出液中回收FePO4。将母液浓缩并保持在约100℃的温度,然后加入饱和碳酸钠溶液以沉淀Li2CO3,此时锂回收率接近80%。