Modelling of Carbothermal Reduction of Tio2-Fe2o3 Composite with Compressed Natural Gas Using Design of Experiment

Abstract

An alternative way to process titanium minerals was investigated via carbothermal reduction/nitridation (CTRN) by yielding titanium oxycarbonitride (TiOxCyNz). Synthetic anatase (TiO2) and hematite (Fe2O3) were mixed together with graphite/CNT mixture to study the reduction kinetics. The reduction process was carried out at 1150 - 1250 °C for 1 to 4 hours in a gas mixture of hydrogen, nitrogen and compressed natural gas. The carbon to reducible oxygen molar ratio (C:Ored) was varied in this experiment from 0.5 to 1.0. The extents of reduction and nitridation with the amount of free carbon deposited were studied using 23 factorial design to define the optimum parameters in producing TiOxCyNz. From Design Of Experiment (DOE) analysis, the most influential factor contributing to the extent of reduction was reduction time, followed by carbon to reducible oxygen molar ratio and reduction temperature subsequently. The highest extent of reduction was 92.68% which was obtained at 1150 °C for 4 hours using sample with C:Ored of 1.