Removal of zinc and alkalis in steelmaking dusts by oxidative leaching

M.J. Soria-Aguilar, F.R. Carrillo-Pedroza* and S. Preciado-Nuñez

Facultad de Metalurgia – Universidad Autónoma de Coahuila, Carr. 57 km 5, Monclova, Coahuila, C. P. 25710 México

Accepted 10 March 2005


Several processes in aqueous media have been developed to treat the dust produced by the steel making industry, specifically dust originated from the Iron Blast Furnace and the Basic Oxygen Furnace, BOF. The dust is not completely recycled due to its high content of zinc, alkali and other elements that affects the process efficiency; therefore this represents an economical lost as a consequence of losing the iron and carbon contained in it. The effort to treat such dust are either conventional like the technology based on H2SO4 to the more advanced based on alkaline lixiviation.
This work shows a comparison among several dust treatments in aqueous media to reduce its zinc and alkali content, using diverse acid and alkaline solutions and oxidants like the ozone. The results obtained show that the elimination of zinc and alkalis can vary from 5% to 80% depending on the treatment conditions (the solution, the oxidant and the temperature). The results show that under very oxidant conditions like those reached by ozone is possible to obtain a larger reduction of zinc and alkali content; this represents an alternative for the treatment and recycle of the dust originated in the steel making processes of Blast Furnace and BOF.

Keywords: Leaching, Steelmaking dust, Ozone, Zinc, Alkalis

* Corresponding author
   E-mail : acm15322@infonte.uadec.mx