Insight into Interaction Behavior of CeAlO3 Substrate and CaO‐Al2O3‐Based Slag

Abstract

Dissolution of inclusion in the melt is a common phenomenon in the metallurgy industry. In this article, the dissolution mechanism of CeAlO3 in CaO‐Al2O3‐Ce2O3‐MgO‐SiO2 slag is investigated at 1550 °C. After CeAlO3 dissolves into slag, the interfacial microstructure and the concentration profiles of the element between CeAlO3 and slag are observed by scanning electron microscopy‐energy dispersive spectroscopy. Results show that an intermediate product CaCeAl3O7 formed during CeAlO3 dissolves into the slag with w(CaO)/w(Al2O3) = 1. There is no intermediate product formed during CeAlO3 dissolves into the slag with w(CaO)/w(Al2O3) above 1.1. With the increase of w(CaO)/w(Al2O3) in the slag, the dissolution of CeAlO3 shifts from an indirect mechanism to a direct mechanism. The dissolution behavior of CeAlO3 in different slags has been discussed based on slag structure. In the first and second stages of dissolution, Ce3+ formed by dissociation of CeAlO3 at the interface diffuses into the slag, and Ca2+ in the slag diffuses to the interface. In the third stage, the solid‐phase precipitation when the concentration of Ca2+, Ce3+, and [AlO4]5− satisfies the nucleation concentration of CaCeAl3O7 in the concentration boundary layer (the region with large concentration gradient near the interface). Conversely, the solid‐phase precipitation could not occur in the concentration boundary layer.