Ligand mediated eco-friendly leaching of zinc from spent catalyst in alkaline media

A novel leaching process for recovering Zn from spent catalyst in alkaline solution has been discussed. The catalyst was characterized for physico-chemical properties by chemical, XRD, TG-DTA and SEM. More than 92% Zn could be extracted from spent catalyst under the conditions: pulp density 2.5% (w/v), NaOH 1 M, EDTA 0.025 M, temperature 80 degrees C and time 3 h. Zn extraction increased with the number of stages. At the 4th stage almost all Zn could be extracted. A tentative process flow-sheet has been proposed based on Zn recovery. Characterization of leach residue by XRD and SEM gave an insight into the mechanism. (C) 2013 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.