The recovery of lead from spent lead acid battery paste (SLP) is not only related to the sustainable development of the lead industry, but also to the sustainable evolution environment. An innovative process is proposed for the recovery of high purity metallic lead from spent lead acid battery paste (SLP) by electrodeposition at 333–353 K in choline chloride-urea deep eutectic solvent (ChCl-urea DES). The electrochemical behavior of SLP on low carbon steel (LCS) electrode has been investigated by cyclic voltammetry and chronoamperometry measurement. Results imply that Pb(IV) could be reduced preferentially to Pb(II) by ChCl-urea DES, which possesses a strong reducibility. Then the reduction of Pb(II) is a diffusion-controlled quasi-reversible process and the diffusion coefficient increases gradually from 2.70 × 10^–8 cm²/s at 333 K to 6.79 × 10^–8 cm²/s at 353 K. The initial nucleation stage of lead on LCS electrode is a three-dimensional instantaneous nucleation process. In addition, the effects of temperature on the current efficiency and specific energy consumption during the recovery of lead have been discussed at 2.5 V for 1 h. The current efficiency is about 90.73% and the specific energy consumption is as low as 712.83 kW h/t at 353 K. Rod-shaped and fern-like lead powders can be obtained with a face-centered cubic structure and the predominately oriented crystallite varies from (200) at 333 K to (111) plane at 343 K and 353 K. This new system can efficiently shorten the production flow, lower the requirement for equipment, and avoiding emission of lead effluent and harmful gases. This article provides a green extraction method of lead and a theoretical guidance for the electrochemical extraction of valuable metals from spent battery materials in close neutral electrolyte.

Graphical Abstract

中文翻译：

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深共晶溶剂电沉积法从废铅酸电池浆料中回收铅

从废铅酸电池浆料（SLP）中回收铅不仅关系到铅行业的可持续发展，也关系到可持续发展的环境。提出了一种创新工艺，通过在氯化胆碱-尿素深共熔溶剂 (ChCl-urea DES) 中电沉积在 333–353 K 下从废铅酸电池浆料 (SLP) 中回收高纯度金属铅。通过循环伏安法和计时电流法测量研究了 SLP 在低碳钢 (LCS) 电极上的电化学行为。结果表明，具有强还原性的 ChCl-脲 DES 可以优先将 Pb(IV) 还原为 Pb(II)。那么 Pb(II) 的还原是一个扩散控制的准可逆过程，扩散系数从 2.70 × 10 ^{–8逐渐增加}cm ² /s 在 333 K 至 6.79 × 10 ^–8 cm ²/s 在 353 K。铅在 LCS 电极上的初始成核阶段是一个三维瞬时成核过程。此外，还讨论了温度对铅回收过程中电流效率和比能量消耗的影响，电压为 2.5 V，时间为 1 小时。电流效率约为 90.73%，353 K 时比能耗低至 712.83 kW h/t。可获得面心立方结构的棒状和蕨状铅粉，主要取向的微晶不同从 333 K 的 (200) 平面到 343 K 和 353 K 的 (111) 平面。这种新系统可以有效缩短生产流程，降低对设备的要求，避免铅废水和有害气体的排放。

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