THE INFLUENCE OF MICROWAVES ON THE LEACHING KINETICS OF ZINC FROM BASIC OXYGEN FURNACE DUST

References: 12th International Multidisciplinary Scientific GeoConference, www.sgem.org, SGEM2012 Conference Proceedings/ ISSN 1314-2704, June 17-23, 2012, Vol. 4, 777 - 786 pp

ABSTRACT

Basic oxygen furnace (BOF) dust is a hazardous metallurgical waste generated in the
collection of particulate material during steel making processes. The occurrence and
recovery of metallurgical wastes from steelmaking and iron making processes are
nowadays the great problem, mainly to their big amount and environmental pollution by
heavy metals potential. The research of non-isothermal kinetics by microwave heating
was evaluated. Experimental results indicate that the most important factor that most
strongly affected microwave acid extraction was the microwave power input. It is
shown that approximately from 22 to 50°C the process is controlled by diffusion with a
low apparent activation energy value of Ea = 1.15 kJ/mol. With increasing temperature
the Arrhenius slope steepness with apparent activation energy value of Ea = 22.01
kJ/mol, which proved that the microwave leaching process from 50°C is under control
by surface chemical reaction. This indicates that the microwave may promote the
mineral solid particle to burst effectively, make the particle expose fresh surface and
strengthen the leaching process.

Keywords: basic oxygen furnace dust, extraction, microwave assisted leaching, nonisothermal
kinetics, zinc recovery