Sulfuric Acid Leaching of Zn and Mn from Waste Zn-C Batteries Using Fe2+ as Reductant

Abstract

Recovery of valuable metals from used portable batteries is gaining widespread importance owing to the conservation of natural sources and possible environmental pollution from these batteries. In this paper, zinc (Zn) and manganese (Mn) recovery from waste zinc-carbon (Zn-C) batteries was investigated. For this purpose, two-stage leaching experiments were conducted in the laboratory. In the first stage, only sulfuric acid (H2SO4) solution was used, and in the second stage, ferrous ion (Fe2+) was added to the H2SO4 solution as a reducing agent. The burnt and wet sieved battery powder was obtained from manually disassembled waste Zn-C batteries. Particle size fraction of -75 + 53 mu m battery powder contained 23.75% Zn and 48.47% Mn. Leaching experiments performed with a solid-to-liquid ratio of 4 g/L showed that Zn and Mn were leached with a recovery of 100% and 58.55%, respectively, using 400 rpm stirring speed, 0.25 M H2SO4 solution, and 70 degrees C temperature. Reductive leaching experiments showed that all of the Mn was recovered in 0.25 M H2SO4 solution using 3.6 x 10(-2) M Fe2+ as a reducing agent at 60 degrees C temperature.