Numerical Simulations of the Impact of CaO/Al2O3 on the Structure and Crystallization Behavior of Red Mud

Abstract

The problem of large stockpiles of red mud needs to be solved, and the use of red mud to prepare inorganic fibers is a new way of applying red mud on a large scale. The role of CaO/Al2O3 in the melting point and melt structure of red mud was investigated by molecular dynamics simulations and thermodynamic calculations. Liquid phase line temperatures for different CaO/Al2O3 systems were calculated using the Factsage program. The radial distribution function and the type of oxygen bonding were used to characterize the effect of different CaO/Al2O3 on the structure of the red mud melt. The melting point of MgAl2O4 is lower than that of CaTiO3 due to the fact that the type of oxygen bonding in MgAl2O4 is predominantly bridging oxygen bonds. When the red mud system has a low SiO2 content and CaO/Al2O3 is between 0.3 and 3.9, the melting point temperature increases significantly, which is not conducive to the fibrillation of the red mud melt.