Non-isothermal reduction kinetics of EAF dust-based pellets

CIM Bulletin, Vol. 94, No. 1049, 2001

B. Peng, J. Lobel, J.A. Kozinski, Department of Metallurgical Engineering, McGill University, Montreal, Quebec M. Bourassa, Atlas Stainless Steel, Tracy, Quebec

Non-isothermal kinetics studies of the reduction phenomenon of electric arc furnace (EAF) dust generated in stainless steelmaking have been carried out. The dust was mixed with carbon as a reducing agent and dolomite as a binder to form pellets. A Thermo-Gravimetric Analyzer (TGA) was used to determine the weight loss of pellets heated at an average rate of 40 K/min. up to a temperature of 1500¡C. The degree of metal reduction was calculated by considering the pellet weight loss, and evaporation of moisture, dust, zinc and lead at high temperature. The reduction process was divided into three different steps. The first covers the 300¡C to 760¡C temperature range (from 7 to 18 min.), the second step ranges between 760¡C and 980¡C (18 to 24 min.), and the third covers temperatures above 980¡C. Each step is characterized by different chemical reactions. Non-isothermal reduction kinetics equations were set up to describe each step. The kinetics parameters such as apparent activation energies and frequency factors were established. It was found that the first step was chemically controlled, while the

Keywords: EAF dust, Waste recycling, Kinetics