First Principles Calculation of Adsorption of Water on MgO (100) Plane.

The hydration reaction seriously affects the quality and performance of MgO-based products. The final analysis showed that the problem is the surface hydration of MgO. By studying the adsorption and reaction of water molecules on the surface of MgO, we can understand the nature of the problem from the root cause. In this paper, first-principles calculations are performed on the crystal plane of MgO (100) to study the influence of the different orientation, sites and coverage of water molecules on the surface adsorption. The results show that the adsorption sites and orientations of monomolecular water has no effect on the adsorption energy and adsorption configuration. The adsorption of monomolecular water is unstable, with almost no charge transfer, belonging to the physical adsorption, which implies that the adsorption of monomolecular water on MgO (100) plane will not lead to the dissociation of water molecule. When the coverage of water molecules exceeds 1, water molecules will dissociate, and the population value between Mg and Os-H will increase, leading to the formation of ionic bond. The density of states of O p orbital electrons changes greatly, which plays an important role in surface dissociation and stabilization.

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.