Hydrometallorgical extraction of cobalt from filter cakeGenerated during electrolytic zinc production
|Location||21th symposium on geosciences|
|Holding Date||24 May 2008|
Cobalt is one of the most harmful impurities, even small amounts of cobalt in the electrolyte (1mg/l) because of the rate of zinc production, was decreased drastically. For this reason in Isfahan Zinc Smelting Factory (IZSF), cobalt is precipitated by adding KMnO4 to the electrolyte in the hot purification stage. The precipitate was used as a secondary resource for cobalt recovery.
The recovery of cobalt from cobalt filter cake was investigated using hydrometallurgical method and effect percent of parameters temperature, time and acid concentration on cobalt recovery identified with software of qualitek-4.
This precipitate mainly contains 1.33% Co, 16.24% Zn, 6.83% Ca, 8.06% Mn. In order to determine water soluble components, the cake was first leached by water resulting in the reduction 45% of sample weight. The residue from previous stage was then leached by sulfuric acid at 2 stages (stage of zinc selective leaching and stage of cobalt leaching) in different condition. Optimum conditions for leaching process were obtained (by qualitek-4 software) as follows; concentration of acid 15%, time 3 hours, temperature 85?c and pulp density 100 gr/l. Under these conditions, cobalt recovery was increased up to 78%.