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 °C, 1.5 h), leaching efficiencies of 97.53% for Li⁺, 1.39% for Fe³⁺, and 2.58% for PO₄³⁻ 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 °C, 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，通过分离活性物质，选择性浸出和逐步化学沉淀，有效回收了废锂离子电池中的贵金属。提出了使用化学计量的Na ₂ S ₂ O ₈作为氧化剂并添加低浓度的H ₂ SO ₄作为浸出剂。此路线与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。当在最佳条件下进行实验时（Na ₂ S ₂ O ₈ -Li摩尔比为0.45，0.30 mol / LH ₂ SO ₄，60°C，1.5 h），Li ^+的浸出效率为97.53 ％，Fe ^3+的浸出效率为1.39 ％，PO ₄ ^3-的浸出效率为2.58％。然后通过沉淀法从渗滤液中回收FePO ₄，同时将pH保持在2.0。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Li ₂ CO ₃。锂的回收率接近80％。