Mold flux characterization for thin slab casting of steel

The mineralogical constitution and the melting-solidification behavior of two commercial fluxes for thin slab casting of steel were determined. The characterization of the commercial fluxes as received show the presence of wollastonite (CaO center dot SiO2), a sodium carbonate (Na2CO3), calcite (CaCO3), fluorite (CaF2) and carbon as the main components by X ray powder diffraction (XRD) and microscopic techniques. When fluxes were heated to 1573 K and further solidification, there was almost a whole transformation from the original compounds to cuspidine (3CaO center dot 2SiO(2)center dot CaF2) and nepheline (Na2O center dot Al2O3 center dot 2SiO(2)) phases. The thermal gravimetrical analysis showed an important weight reduction in both fluxes due to the thermal decompositions of calcite and sodium carbonate. The characterization reveals that fluxes are produced by an agglomeration process.