Effect of TiO2 percentage on the hydrogen-based direct reducibility of high-grade pellets

The steel industry relies heavily on the direct reduction of iron ore pellets, which is a more environmentally friendly alternative to traditional blast furnaces, by reducing CO 2 emissions. This study investigated the effects of different TiO 2 contents on the reducibility of high-grade iron ore pellets using hydrogen (H 2 ). The research employed HSC chemistry, COMSOL Multiphysics, and X-ray tomography to analyse the thermodynamics and kinetics of hematite reduction. The results indicate that TiO 2 significantly affects reducibility; pellets with less than 0.5 % TiO 2 show improved reducibility due to favorable microstructural changes, while higher TiO 2 content reduces porosity and slows down reduction rates. However, increasing the H 2 pressure to 8 bar mitigated the detrimental effects of the high TiO 2 content and improved the porosity and reduction kinetics. These results support the theoretical predictions, provide guidelines for optimizing pellet formulations, and emphasize the importance of controlling the TiO 2 content and operating conditions for efficient reduction processes. • TiO2 below 0.5 % increases the reducibility of pellets by improving the structure. • A high TiO2 content reduces porosity and slows down reduction rates. • Higher hydrogen pressure offsets the negative effects of TiO2. • Study aligns theoretical predictions with the actual reduction behavior.