Reduced Energy Recycling of Lead Acid Batteries (RELAB)

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The need to reduce energy demand is felt most keenly in the energy intensive industries (EEIs), of which the manufacturing of metals such as iron and steel, as well as non-ferrous metals, are a large constituent. The lead industry has in the last few decades developed effective processes for the recycling of metallic lead from (principally) lead acid batteries. The batteries are crushed (to remove the plastic), desulfurised, smelted and then refined to produce lead bullion which can be reused to make new batteries. Whilst very high rates of recycling are achieved, the entire process in very energy intensive, mainly from the milling and the smelting but also from the need to eliminate any lead-to-air emissions. Whilst the principles of this pyrometallurgical process have remained relatively unchanged for centuries, this proposal seeks to develop a novel solution-based electrochemical route to lead recycling using deep eutectic solvents (DESs).Deep eutectic solvents have been applied to a number of different technological applications, owing to their relatively low cost, ease of handling, low environmental impact and, most importantly, their ability to dissolve a wide range of inorganic compounds - including oxides. We propose to dissolve lead paste - from lead acid batteries - in DESs and design novel electrochemical cells for the extraction of high purity metallic lead. This will be done in conjunction with Envirowales Ltd, a lead-acid battery recycler, as our project partner.The main objective of the project is to develop a new electrochemical technology for lead-acid battery recycling based on a solution-based processing. We aim to understand the behaviour of speciation of Pb within the solvent, as well as the effects of secondary cations and electrode poisoning. We aim to design and build a number electrochemical cells (from bench-top to pilot plant prototype), that will replace the smelting steps in the current high temperature process. This will be supported by accurate total energy modelling of the current pyrometallurgical process with which to benchmark our energy gains by switching to the new technology. We envisage that not only will this technology have a lower overall energy demand, but will also be cleaner, due to a significant reduction in lead-to-air emissions.