Recovery of Zn from Unsorted Spent Batteries Using Solvent Extraction and Electrodeposition

Abstract

This study focused on the selective recovery of zinc (Zn) from a leaching solution emerging from a sulfuric acid leaching process applied to unsorted spent batteries. Precipitation and solvent extraction were investigated. According to the results, solvent extraction using Cyanex 272 allowed for the selective removal of Zn from the solution containing high amounts of metals (∼19.4 g Zn/L, ∼23.4 g Mn/L, ∼3.27 g Cd/L, ∼3.19 g Ni/L, and ∼.25 g Co/L). According to the results, the solvent extraction process was capable of recovering 97.6% of Zn from this leaching solution under the following conditions: two stages of extraction in the presence of an organic solution made of Cyanex 272 (3%, v/v) and tributylphosphate (TBP—2%, v/v) in kerosene, pH=2.2, organic/aqueous (O/A) ratio = 2/1, and T=5°C. The Zn present in the organic phase was then stripped using .4 M H2SO4 with an O/A ratio fixed at 2/1. This stripping step allowed for the recovery of 81.8% of the Zn initially present in the organic phase. Subsequently, 82.4% of the Zn stripped in the aqueous solution was then electrically deposited after 3 h at pH=2 with a current density fixed at 36 A/m2.