Cobalt and manganese recovery from spent industrial catalysts by hydrometallurgy

In the present work, hydrometallurgical techniques were applied in order to recover cobalt and manganese from fly ash coming from incineration of spent industrial catalysts. Washing steps with water were carried out, with the aim of removing the soluble salts. The residue was leached in order to establish the optimal operative conditions. Cobalt/manganese separation was investigated by solvent extraction, using Cyanex 301 in kerosene as an extractant varying pH, extractant concentration and organic/aqueous volume ratio. Stripping tests were performed to re-extract cobalt ions in a new aqueous phase, employing hydrochloric acid as stripping agent. The proposed process allows to recover 99.7% of cobalt and 86.6% of manganese.