Prospects of Eliminating Fluorspar Consumption in a Sustainable Argon‐Oxygen‐Decarburization Process

Fluorspar serves the critical functions of facilitating lime dissolution and liquid slag formation in the argon‐oxygen‐decarburization (AOD) process. Yet, it is a material with long‐term supply risks that requires a gradual replacement. Thermodynamic calculations and industrial AOD trials were performed in this study to identify different pathways for eliminating fluorpsar addition during the production of 304 stainless steel. FactSage calculations suggest that the suitable amount of flux to replace 5 wt% CaF ₂ during the reduction phase (B4 = 1.6) is 20 wt% Al ₂ O ₃ , 5 wt% Na ₂ O, 5 wt% K ₂ O, or 3 wt% Li ₂ O. Likewise, the suitable amount of flux to replace 12 wt% CaF ₂ during the desulphurization phase (B4 = 2.1) is 20 wt% Al ₂ O ₃ , 9 wt% Na ₂ O, 12 wt% K ₂ O, or 6 wt% Li ₂ O. During one industrial AOD trial where 50 wt% of ferrosilicon reducing agent was replaced by aluminum, the overall fluorspar consumption was reduced by 75% in weight and the final sulfur content in the liquid steel at tapping was two times lower than that measured during the reference heat. In summary, the application of an aluminum reduction agent or the addition of alternative fluxes are both effective strategies for eliminating fluorspar without compromising the quality of the steel produced.