Kinetics of isothermal reduction of
stainless steelmaking dust pellets①
stainless steelmaking dust pellets①
(1. College of Metallurgical Science and Engineering, Central South University, Changsha 410083, China;
2. College of Information Science and Engineering, Central South University, Changsha 410083, China;
3. Department of Metallurgical Engineering, McGill University, Montreal, QC, Canada H3A 2B2)
2. College of Information Science and Engineering, Central South University, Changsha 410083, China;
3. Department of Metallurgical Engineering, McGill University, Montreal, QC, Canada H3A 2B2)
Abstract: The stainless steelmaking dust pellets were reduced in isothermal temperature condition simulating the direct recycling practice in the stainless steel production and the kinetics of the reduction process was investigated. The pellets were formed after mixing the dust with carbon as the reducing agent and dolomite as the binder and smelting flux. An electric furnace was used to heat the pellets and an electrical microbalance was used to check the mass of the pellets in the
reduction process. The reduction rate was calculated according to the data of pellet mass change in consideration of the evaporation of moisture, zinc and lead at high temperature. The results of the experiments show that the reduction process is in two consecutive stages. The reduction kinetic models were set up for each stage and the kinetic parameters such as activation energy and frequency factor were determined. The apparent activation energy of the first stage is 21.69 kJ/mol, and this stage is controlled by chemical reaction. The apparent activation energy of the second stage is 17.35 kJ/mol, and this stage is controlled by the diffusion of carbon monoxide through the resultants of reaction.
reduction process. The reduction rate was calculated according to the data of pellet mass change in consideration of the evaporation of moisture, zinc and lead at high temperature. The results of the experiments show that the reduction process is in two consecutive stages. The reduction kinetic models were set up for each stage and the kinetic parameters such as activation energy and frequency factor were determined. The apparent activation energy of the first stage is 21.69 kJ/mol, and this stage is controlled by chemical reaction. The apparent activation energy of the second stage is 17.35 kJ/mol, and this stage is controlled by the diffusion of carbon monoxide through the resultants of reaction.
Key words: stainless steelmaking dust; isothermal reduction kinetics; pellets; direct recycling