Review on clean recovery of discarded/spent lead-acid battery and trends of recycled products

Emissions of lead particulates, sulfur oxides and their potential environmental risks are received great attention in traditional pyrometallurgical process for recycling spent lead-acid battery. In recent years, environmentally-friendly processes operating at near ambient temperatures show a good prospect for the recovery of spent lead-acid batteries, including electrowinning, organic acid leaching-calcination, and alkaline leaching-crystallization processes. The recovered products such as leady oxide (mixture of PbO and metallic Pb) and pure lead oxide from hydrometallurgical processes could be directly re-utilized as active materials in manufacturing of new batteries. A hydrometallurgical recovery route can eliminate the smelting procedure for lead ingot production and the following steps of Ball-milling or Barton liquid lead atomizing for leady oxide production in conventional lead mass flow from spent lead-acid battery to new lead-acid battery. Two technological challenges in hydrometallurgical recovery process for spent lead-acid battery are recognized as: removal of impurity elements (such as Fe and Ba) and loop reuse for reducing dosage of leaching reagents. Bibliometric analysis of recovery of spent lead-acid battery based on recent publications from 1987 to 2018 shows that the organic acid leaching-calcination process is the most frequently published technology in hydrometallurgical processes, meanwhile leady oxide and lead oxide are the most recovered products.