Abstract

Recently the iron and steel makers as well are much more concerned with the by-products and waste streams generated in their ferrous metallurgical industries. In general, the relevant minor or trace elements (Si, Mn, P, Al, S, As, Cu, Zn, K, Na, Ti, Cr, V, W etc.) are not concentrated very much in the different slags and dust produced and collected during the subsequent processing steps of iron and steelmaking. However, zinc can be an exception, especially when zinc containing (e.g. hot dip galvanized) steel scraps are recycled in electric arc furnaces (EAF) to produce new unalloyed steels.

The paper describes, in short, a few examples of the recovery of some valuable metals from such byproducts, then reviews the major selective leaching processes tested or being applied to reclaim pure zinc compounds or metallic zinc as a by-product of the EAF secondary steel making technology. Based on own laboratory experiments the technical feasibility is also discussed of the selective leachability and removal rate of lead from the residues of the ammonia - ammonium carbonate (AAC) leaching of EAF dust. Secondary leaching of such residues obtained after AAC leaching was performed in laboratory autoclaves equipped with mechanical stirring and used up to 250°C.