Effect of Mg with Different Combination Form of Mg–Ca in MgO-Bearing Fluxes on Fluidity of Liquid Phase in Sintering Process

MgO was considered to be an indispensable mineral composition of the modern sintering process. Fluidity of liquid phase reflecting the scope of effective bonding makes a clear distinction among MgO-bearing fluxes in the sintering process. Mg–Ca combination forms of dolomite, l-dolomite, serpentine and their influence on the fluidity of liquid phase and bonding strength of sinter body were investigated and analyzed. The results showed that there were non-separated, partly-separated, and completely-separated states of Mg–Ca in different MgO-bearing fluxes. Furthermore, development of the separation degree of Mg–Ca combination states led to the decrease of Mg content melt in silico-ferrite of calcium and aluminum (SFCA) and increase of Mg content in magnetite. Consequently, fluidity of liquid phase was improved due to decline of viscosity of liquid phase. Moreover, bonding strength had a good positive correlation with fluidity of liquid phase. Hence, increase of Mg–Ca separation degree was beneficial for improvement of bonding strength.