Process for the treatment of alkaline spent batteries

In recent years there has been a growing interest in processes for the treatment of spent portable batteries, due to problem of environmental impact connected with the presence of significant quantities of heavy metals. As a matter of fact, batteries are considered special waste by current legislation that establishes specific rules for the collection, treatment, recycling and disposal of spent batteries and accumulators. In this work a process for the treatment of spent alkaline batteries is presented (Toro et al., 2006). The hydrometallurgic process comprises the following stages: Pre-treatment Acid-reducing leaching using carbohydrate as reducing agent Leach-liquor purification Separation and recovery of metallic Zn and MnO(2) (by electrowinning) The aim of this work is the optimization of the operating conditions for the selective recovery of Zn. Leaching tests were performed both at room temperature and at 90 degrees C. Experimental results denoted that at room temperature a quantitative zinc extraction was obtained with selectivity higher than at 90 degrees C. Leach-liquor solution after purification (iron precipitation and cementation) was used in electrowinning process for recovery of zinc which was obtained with 98-99% purity.