Effect of TiO2 percentage on the hydrogen-based direct reducibility of high-grade pellets
Behzad Sadeghi, Pasquale Cavaliere, Mutlucan Bayat, Marieh Aminaei, Niloofar Ebrahimzadeh Esfahani, Aleksandra Laska, Damian Koszelow, Natalia Ramos Concalves
Abstract
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.