Reaction Mechanism of CA₆, Al₂O₃ and CA₆-Al₂O₃ Refractories with Refining Slag

In this study, to clarify the corrosion mechanism of CA₆ based refractory by refining slag, the static crucible tests for CA₆, CA₆-Al₂O₃, and Al₂O₃ refractory, were carried out and the detail reaction processes were analyzed from the perspective of thermodynamic simulation and structural evolution. From the results, CaAl₄O₇ plays a vital role in the slag corrosion resistance of the three refractories. Regarding CA₆ refractory, the double pyramid module in CA₆ crystal structure was destroyed very quickly, leading to the rapid collapse of its structure to form the denser CaAl₄O₇ in high amounts. As a result, a reaction layer mainly composed of CaAl₄O₇ formed, which effectively inhibited the slag corrosion, so CA₆ refractory exhibits the most excellent slag corrosion. Meanwhile, the formation of CaAl₄O₇ can also avoid CA₆ particles entering the molten steel to introduce exogenous inclusions. For Al₂O₃ refractory, the generation of CaAl₄O₇ is much slower than that of CA₆ and CA₆-Al₂O₃ refractory, and the amount generated is also quite small, resulting in its worst slag corrosion among the three crucibles. Therefore, CA₆ based refractory has excellent application potential in ladle refining and clean steel smelting.