Research on hydrogen-based direct reduction sticking and inhibition methods for vanadium–titanium pellets

Hydrogen-based shaft furnaces use hydrogen instead of coke and are regarded as a key route for low-carbon steel production. However, under high-temperature direct reduction conditions, sticking of direct reduced iron may occur, which deteriorates bed permeability and affects production stability. In this study, reduction-under-load tests were conducted to simulate the atmosphere of a hydrogen-based shaft furnace and to investigate the effects of total reduction time, temperature, and coating materials (CaO, MgO, TiO₂) on the sticking behavior of vanadium–titanium pellets. The results show that sticking was strongly affected by reduction time at 1100 °C. When the total reduction time reached 2.5 h, the sticking index and sticking strength reached their maximum values of 97.11% and 16.23 N, respectively, and then decreased with further extension of time, while the metallization rate gradually declined. Increasing temperature markedly intensified sticking behavior, whereas the metallization rate changed little. Among the coating materials, TiO₂ exhibited the strongest inhibitory effect by forming a dense barrier layer and Fe–Ti–O interfacial products that reduced direct particle contact and suppressed the development of sticking phases.