Electric arc furnace dust non-isothermal reduction kinetics①
(1. Department of Metallurgical Science and Engineering,
Central-South University of Technology, Changsha 410083, P.R.China;
2. The Department of Metallurgical Engineering,
McGill University, Montreal, QC, H3A 2B2, Canada)
Central-South University of Technology, Changsha 410083, P.R.China;
2. The Department of Metallurgical Engineering,
McGill University, Montreal, QC, H3A 2B2, Canada)
Abstract: Kinetic studies of the electric arc furnace (EAF) dust reduction process have been carried out under nonisothermal temperature condition. EAF dust pellets were made with carbon as the reducing agent and dolomite as the binder. A Thermo-Gravimetric Analyzer (TGA) was used to determine the mass loss of pellets, which were heated at an average rate of 40 K/min up to 1500℃. The reduction degree was calculated by consideration of the pellet mass loss, evaporation of moisture, dust, zinc and lead at high temperature. The reduction process of EAF dust was divided into three steps related to the change in temperature and time. The non-isothermal reduction kinetics equations were set up to describe every step. The kinetics parameters such as apparent activation energies and frequency factors were established at the same time. It was found that the first step is chemically controlled, the second step is diffusion-controlled and the third step is strongly dependent on the initial content of carbon in the pellet. CrO can be reduced only in the last step by high temperature and high initial carbon content.
Key words: EAF dust recycles; chemical kinetics; non-isothermal reduction