Optimization of Hydrogen Reduction of Kahnuj Ilmenite Using Response Surface Methodology (RSM)

The hydrogen reduction of Kahnuj ilmenite concentrate (Kerman, Iran) was studied under different process parameters using Response Surface Methodology (RSM). The effect of major influencing parameters on the reductive mass loss of pellets made from ilmenite concentrate was elucidated. The independent variables examined consisted of the reduction temperature range of 850–1050 °C, pre-oxidation temperature range of 800–1000 °C, and gas flow rates of 200–500 mL min⁻¹. It was found that the reduction temperature and pre-oxidation temperature were the most significant factors affecting the mass loss. The optimum mass loss conditions were determined to be a reduction temperature of 1045 °C, pre-oxidation temperature of 860 °C, and hydrogen flow rate of 217 mL min⁻¹. The optimal experimental mass loss of 15.1% was in accordance with the predicted value of 15.3%. The ilmenite phase transformed into metallic iron, rutile, reduced rutile, and M₃O₅ solid solution through the reduction process.