Juergen Antrekowitsch

Abstract:

Steel mill dust nowadays is a well-known secondary resource for zinc. Most of the companies treating this dust operate the established waelz process. However, even though it is known as best available technology, it finally only recovers zinc and does not create any value out of the other metals contained in the dust such as lead, iron etc. Moreover, the waelz process generates huge amounts of new residues which become more and more difficult to landfill. The often promoted concept of circular economy also requires a more efficient use of different resources to avoid the loss of raw materials. With this even the waelz kiln operators have started to think about utilization of the resulting slags and an optimized use of the produced zinc concentrate which also includes lead. Beside this, new developments try to offer better solutions especially regarding the realization of zero waste strategies. This paper discusses different options for a multi-metal recovery out of steel mill dust from the technical as well as economical point of view. Special emphasis is put on a development done at the University of Leoben. This so called 2sDR-process (two-step-dust-recycling) tries to combine two general aims, the recovery of different metals and the generation of a high quality zinc product and is currently undergoing the upscaling process to a pilot plant size.