Intrinsic kinetics of the chlorination of hematite powder between 898 and 1023 K

The kinetics of the chlorination of hematite powder was investigated between 898 and 1023 K by isothermal thermogravimetry. The influence of the chlorine partial pressure and sample size on the reaction rate was studied between 15 and 70 kPa and between 0.5 and about 50 mg, respectively. The reaction occurs under mixed control; pore diffusion and chemical reaction are the rate-controlling steps. An apparent reaction order of 0.5 with respect to chlorine partial pressure (that implies a zero intrinsic order) and a value of activation energy of 451 kJ/mol were found.