Molecular dynamics study of structural properties of refining slag with various cao/al2 o3 ratios

Abstract

SiO2-Al2 O3-CaO-MgO is the main type of refining slag in a ladle furnace. Here the effects of the CaO/Al2 O3 mass ratio on the structural properties of the refining slag system are studied by molecular dynamics simulations. The pair distribution function, coordination number, microstructure unit and diffusion capacity were analyzed. An increase in the CaO/Al2 O3 ratio did not change the bond lengths of these units. However, an increase of the CaO/Al2 O3 ratio caused more charge compensators to be introduced into the refining slag system, which led to conversion of free oxygen and non-bridging oxygen to tricluster oxygen and bridging oxygen in the system. Moreover, this augmented the content of relatively stable 4-and 5-coordinate Al. As the micro-structure of the system became more complex, the overall diffusion capacity of the refining slag became poorer. In the micro-structure, the diffusion capabilities of different atoms decreased in the following order: Mg > Ca > O > Al > Si.