Manganese recovering from alkaline spent batteries by ammonium peroxodisulfate

Abstract

The process of manganese removal from spent battery leaching solutions, with ammonium peroxodisulfate, prior to recovery of zinc by electrolysis is presented. The experiments were carried out according to a 23 full factorial design considering ammonium peroxodisulfate concentration, temperature and pH as factors investigated. The analysis of variance (ANOVA) was carried out on the precipitation yields of Mn and Zn after 30 min, 1h, 2h and 3h of reaction. Optimal conditions for obtaining Mn as MnO2 have been 20% (NH4)2S2O8, 90 °C and pH 6. Data from XRF and AAS during the reaction at different time are presented to analyse the kinetic behaviour of the system. The MnO2 precipitated and solutions were characterized by XRF and XRD. The solid samples were kept at 800 °C for 1 h to produce chemical manganese dioxide (CMD) and were characterized by cyclic voltammetry for their electrochemical activity. The overall results denoted that chemical oxidation of manganese from spent batteries leaching solutions with ammonium peroxodisulfate is a suitable method for manganese recovery as MnO2 prior zinc recovery by electrolysis, also to produce of a suitable product (CMD), in other words, it could be used in a process for recycling spent batteries.