Influence of fluorspar replacement in desulfurizing mixtures and variation of process parameters on the hot metal desulfurization efficiency

Abstract

Fluorspar (CaF₂) is the most used flux in hot metal desulfurizing mixtures. However, its use can cause refractory wear and environmental contamination, prompting research efforts to develop alternative desulfurizing mixtures. This study aims to investigate the replacement desulfurizing mixtures containing fluorspar by other desulfurizing mixtures containing a new flux developed without fluorspar named MIX. The influence of varying the mass of these desulfurizing mixtures, temperature, and stirring of the system on the efficiency of hot metal desulfurization was also studied. The desulfurization experiments were carried out in an electric resistance furnace, at a temperature of 1370°C. Hot metal samples were taken to measure the change in sulfur content in the experiments. FactSage 8.0 software, was used to determine the phases present in the desulfurizing mixtures, and these phases were correlated with the hot metal desulfurization efficiency. The efficiency of the desulfurizing mixtures was also correlated with the Desulfurization Factor. The results showed that desulfurizing mixtures containing fiuorspar are the most efficient mixtures. However, fluorspar-free desulfurizing mixtures containing MIX can achieve similar efficiencies with increases in mass, temperature, and system stirring. The results also showed that the most efficient desulfurizing mixtures are those with higher percentages of solid CaO and lower percentages of the solid phases 3CaO.SiO₂ and CaS and, consequently, a higher Desulfurization Factor.

Keywords:
hot metal; desulfurization; fluorspar replacement; desulfurization factor