Recovery of valuable metals from EAF steel making dust by hydrometallurgy

Research Project, 2015

Detailed characterization was done before hydrometallurgical treatment and also the solid rest after the leaching were characterized to find out how much of the Zn stayed in the solid sample and in which phase. In the second part, the hydrometallurgical study determined the effects of studied parameters on zinc leaching as well as on the impurities leaching. Based on the results the optimal conditions were selected to leach out the zinc obtaining quite high efficiencies (80%) in a single step. Zinc was recovered selectively from iron and other impurities.

The characterization has shown the presence of the phase franklinite, in which Zn is entrapped. It was found out that three samples are suitable source for zinc recovery. The hydrometallurgical study has provided information for a selection of the optimal leaching conditions. It was determined that higher temperature is needed to reach high efficiency. 8M NaOH solution is sufficient for a Zn recovery at given conditions. Solid to liquid ration can be lowered to 1/30 sustaining the effectivity of the process. Zinc can be recovered from such a material in less than two hours.