Isothermal Oxidation Kinetics of Artificial Magnetite Pellets

Abstract

In order to establish the kinetics of oxidation of artificial magnetite pellets, we comprehensively studied kinetics of the oxidation of artificial magnetite pellets from low temperature to high temperature using chemical analysis. The results show that when the oxidation temperature is below 1 073 K (800 °C), the reaction is controlled by the step of internal diffusion, and the model function is 2 G(a) = 1−3(1−x)^2/3 + 2(1−x) (α, reaction degree). When the temperature is above 1 073 K (800 °C), the reaction mechanism was chemical reaction, and the model function is 1 G(a) = 1−(1−x)^1/3. The apparent activation energy for the oxidation of artificial magnetite pellets was also determined, which was 8.90 kJ/mol for the low temperature and 67.79 kJ/mol for the high temperature. Based on the derived kinetic equation for the oxidation of artificial magnetite pellets, the calculated value is consistent with the experimental data. Compared with that of nature magnetite pellets, the apparent activation energy is decreased obviously, which indicates that the artificial magnetite pellets are oxidized more easily than nature magnetite pellets.

Keywords

artificial magnetite / pellets / oxidation kinetics / shrinking