The Recovery of Lead from Spent Lead Acid Battery Paste by Electrodeposition in Deep Eutectic Solvent

摘要

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 x 10(-8) cm(2)/s at 333 K to 6.79 x 10(-8 )cm(2)/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. [GRAPHICS] .