Nowadays nearly the half of the world zinc production is used for galvanizing. After their life span most of the galvanized products return as scrap to the steel mill. During the steel process the zinc is collected in the flue dust. It is astonishing to notice that between 40 and 50 ％ of the zinc produced is brought into the steel processing cycle by the coated scrap while only 3 to 5 ％ of the zinc production can be covered by the recycling of the zinc bearing steel mill dusts. Responsible for this worse ratio is the fact that the established recycling technologies suffer from high energy consumption， low zinc yields, halogen problems and hardly any iron recovery. A development of new or an optimization of current recycling procedures for the dusts is unalterable because of increasing zinc amounts in these residues and the rising costs for the disposal. Different pyrometallurgical recycling technologies are tested in rotary kilns and vertical retorts at the Department of Nonferrous Metallurgy. University of Leoben, Austria. Various reducing agents from carbon monoxide to hydrogen and combinations are used. The results should make it possible to draw conclusions that allow an economical and ecological judgement of the different varieties. The goal is to support the affected industry to increase the low recycling rate and prevent a loss of high zinc values in the steel industry filter dusts.
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