The Recovery of Zinc and Manganese from Synthetic Spent‐Battery Leach Solutions by Solvent Extraction

Recycling zinc‐carbon spent batteries is receiving growing interest due to environmental concerns and also the large quantity involved. It would therefore be advantageous to develop a solvent‐extraction (SX) process for the recovery of zinc and manganese from spent zinc‐carbon battery leach solutions. Among the two systems considered, D2EHPA and Ionquest 801, the latter is a better choice in terms of metal separation and stripping. It was shown that two theoretical stages are needed for the extraction of iron and zinc with the system containing 30% (v/v) Ionquest 801 and 5% (v/v) TBP in Shellsol D70 at an A/O ratio of 1:1, pH 3.0, and 40°C. The extraction kinetics of iron and zinc were very fast, and their extractions reached 99% and 93% within one minute, respectively. Less than 1% of the manganese was extracted in two minutes. The stripping kinetics of zinc was very fast, with over 97% being stripped in 30 seconds. The selective stripping of zinc from iron could be achieved at pH 0.5. Iron cannot be stripped effectively with the stripping solution containing 40 g/L zinc and 170 g/L H2SO4. Thus, an organic bleed stream could be needed to strip the iron with 400 g/L sulphuric acid. A process flowsheet has been proposed for the recovery of zinc and manganese from spent zinc‐carbon battery leach solutions using the Ionquest 801/TBP system. The advantage of this process is that both pure zinc and manganese product solutions could be obtained.