Impact of CO2 as an oxidant on the decarburization and chromium retention and an approach for CO2 recycling

This study explores the unique role of CO 2 as an oxidant in stainless steel smelting, focusing on its effectiveness in decarbonization and chromium retention. The research begins by theoretically demonstrating that although the introduction of CO 2 increases the CO partial pressure in the reaction system, the decarburization and chromium (Cr) retention capabilities of CO 2 can still be stably maintained through the rational adjustment of the molten steel composition, temperature, and inert gas proportions. Further experimental findings indicate that chromium does not exhibit significant oxidation losses when the carbon (C) content exceeds 1.0% (mass). Finally, a novel CO 2 recovery and utilization approach is proposed, integrating CO 2 capture from smelting flue gas and recycling it for smelting, reducing O 2 consumption and energy costs. This innovative process, compatible with existing smelting plants, presents a promising pathway towards carbon neutrality in the iron and steel industry, bridging theoretical insights with practical applications. • CO 2 exhibits potential as a novel oxidant in stainless steel smelting. • CO 2 demonstrates significant Cr retention ability at C content above 1.0 wt%. • Proposing a new CO 2 recycling process tailored to stainless steel smelting.