The RecoDust Process-Upscale of a Pilot Plant

The RecoDust process is a pyrometallurgical approach for the treatment of heavy metal-containing basic oxygen furnace dusts (BOFD) and delivers two products without any residues: the iron rich RecoDust slag and a zinc rich filter dust, called crude zinc oxide (CZO). The state of the art Waelz process has some disadvantages and is only suitable for dusts with zinc contents >15%. Within the frame of a project of the Austrian competence center program K1-MET and with financial support of voestalpine Stahl, a RecoDust pilot plant is operated at the Chair of Thermal Processing technology at the Montanuniversitaet Leoben and has shown good dezincification rates of BOFD in eleven smelting campaigns with a throughput up to 300 kg h(-1). The target is the design of an industrial plant with a throughput capacity of 1000 kg h(-1)in the next years. For the upscale, a new pneumatic conveying system was installed at the pilot plant, which uses natural gas as conveying medium. The commissioning of the developed pilot plant was successful and revealed a good product quality of the CZO. An enhanced dezincification of the RecoDust slag is one open challenge, therefore the dust feed conveying must be more precise.