Effect of calcium fluoride and magnesia on the performance of tundish coverture fluxes made of blast furnace slag

Preparation of the tundish coverture fluxes by the blast furnace slag can recycle utilization of solid wastes discharged from iron and steel industry. Calcium fluoride and magnesia can play an important role for the basic performance of tundish coverture fluxes. The impact on the melting temperature, viscosities and surface tension of the tundish coverture fluxes from the content of calcium fluoride and magnesia were studied. The results showed that: When the content of CaF₂ increased from 10% to 25%, the melting temperature, the viscosity and the surface tension were decreased by 50°C, 0.3 Pa S and 0.039 N/m respectively. The viscosity was brought down of 0.02 Pa S, the surface tension was increased by 0.03 N/m, and the difference between the lowest and highest melting temperature was about 3°C when the content of MgO changed from 5% to 11%.