Thermodynamic Study on Substitution of CO_2 for Ar or O_2 in AOD Smelting Process

摘要

The traditional stainless steel smelting process used O_2 blowing to achieve decarbonization and chromium conversation. The increase of steel production is accompanied with an increase of CO_2 emissions while CO_2 has weak oxidation at high temperatures. The feasibility of using CO_2 for stainless steel smelting in AOD furnaces and the effect of decarbonization and chromium conservation were verified by thermodynamic calculations in this paper. The theoretical calculations show that CO_2 can completely replace O_2 blowing which is convenient to control the progress of the reaction in the bath. The CO_2 injection ratio should be controlled between 20 and 40%. High proportion of CO_2 injection will not only make the molten pool temperature too low, but also extend the smelting cycle. In addition, the higher the CO_2 jet flow, the higher the decarbonization rate in the middle and late stage of the smelting process.