Isothermal and non-isothermal kinetic modelling of carbothermal reduction of Titanium Dioxide-Iron (II) Oxide (TiO2-Fe2O3) composite with natural gas

Titanium metal can be obtained through low cost carbothermal reduction process with the end product of titanium oxycarboniterate (TiOxCyNz). Kinetic modeling is required to understand the carbothermal reduction reactions to control the process more effectively. The objective of this paper is to compare the theoretically predicted results with the experiment results of TiO2-Fe2O3 for three manipulated parameters and to model the kinetic mechanisms of reduction process using the shrinking core model. Synthetic anatase and hematite were mixed with carbon in order to study its carbothermal reduction kinetics reaction experimentally. Then, a shrinking core model was developed to determine the theoretical extent of reduction at different temperature (1150 and 1250 degrees C) when reactant gas diffused into the solid pellet sample. The model was simulated for two conditions, namely isothermal and non-isothermal reduction. It is assumed that the pellet has number of shells which would react uniformly and completely. This model was developed by applying physical and thermodynamics properties of elements/compounds involved in the reaction. It was observed that non-isothermal condition model has lower extent of reduction compared to isothermal condition. while the non-isothermal extent of reduction model is the closest to the experimental compared to the isothermal model. The extent of reduction predicted by the model deviated from experimental but still had similar trend of reduction. i.e., high reduction concomitant with high temperature and time. (C) 2019 Elsevier Ltd. All rights reserved.