Effect of refining slag compositions on its melting property and desulphurization

Abstract

Abstract To investigate the feasibility of the refining slag with low fluoride, some oxides such as Al2O3, SiO2, B2O3, and Li2O were used to replace CaF2 in refining slag with the equivalent weight replacement method, and then the melting temperature and desulphurization capacity of slag were determined. The results show that the melting temperature of slag (CaF2 < 4 mass% and Al2O3 > 28 mass%) is less than 1,706 K, when CaF2 is substituted by Al2O3. This slag is able to decrease [S] in steel to less than 0.0060 mass%. In the case of substitution of CaF2 by SiO2, the melting temperature increases, while the desulphurization rate decreases. The fluxing action of B2O3 is stronger than that of CaF2, and the melting temperature decreases to 1,561 K when CaF2 is substituted by B2O3. Li2O can not only lower the melting temperature of slag but also improve the desulphurization rate.