Use of Computational Thermodynamics in the Analysis of Hot Metal Desulphurization with Slags Based on Marble Waste and Sodalite

摘要

The steel industry is going through transformations aiming at the innovation and use of alternative raw materials. Thus, the use of industrial wastes in synthetic slag production is considered an important alternative to search for new materials and waste reuse. Therefore, the aim of the current study is to study the use of synthetic slags in hot metal desulphurization. It was proposed the use of sodalite instead of fluorspar and the use of marble waste instead of lime. Marble waste was characterized by chemical analysis, X-ray diffraction (XRD) and thermogravimetric analysis. The XRD showed the presence of compounds such as CaCO3, MgCO3 and SiO2. Subsequently, simulations using Thermo-Calc were performed in order to obtain thermodynamic data of the present phases, and to compare them to experimental data. The experimental procedures were carried out at 1400 degrees C. In addition, hot metal tests were performed using an alumina rotor to increase the desulphurization. In hot metal desulphurization, solid CaO phase was responsible for sulfur removal. Furthermore, Ca3O3. SiO2 and Ca3O3. Al2O3 phases limited the reaction, and their concentrations were higher in the slags with marble waste and sodalite, due to the presence of SiO2 and Al2O3 in these raw materials.