Emerging Electrochemical Techniques for Recycling Spent Lead Paste in Lead-Acid Batteries

Spent lead paste (SLP) obtained from end-of-life lead-acid batteries is regarded as an essential secondary lead resource. Recycling lead from spent lead-acid batteries has been demonstrated to be of paramount significance for both economic expansion and environmental preservation. Pyrometallurgical and hydrometallurgical approaches are proposed to recover metallic lead or lead oxide from SLP. However, traditional pyrometallurgical techniques are plagued by high energy consumption and substantial environmental pollution, whereas hydrometallurgical processes suffer from excessive reagent consumption and wastewater emissions. Benefiting from the technical advantages, electrochemical techniques in the recycling of SLP have attracted extensive interest in the last few years. This review provides a comprehensive summary of electrochemical approaches, technical feasibility, and improvements in recycling SLP. These methods mainly consist of leaching-electrowinning, direct solid-phase electrolysis, suspension electrolysis, electrolysis in ionic liquids, and electrolysis in molten salt. The recent research advances in electrochemical recycling of SLP are discussed. The present state-of-the art challenges and issues including energy consumption and impurity behavior in electrochemical treating SLP are also addressed.