Molecular Dynamics Analysis of the Structural Behavior of Aluminum Ion in the Slag of CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–Li<sub>2</sub>O System
Shiyan Jiao, Peiyao Guo, Feichi Chen, Yi Min, Chengjun Liu
Abstract
In the study of CaO–SiO 2 –Al 2 O 3 –Li 2 O system slag, molecular dynamics simulations are performed to analyze the behavior of Al 3+ at different alkalinities. The results show that the AlO bond length increases with increasing alkalinity and is unstable compared to the SiO bond. The [AlO 4 ] 5− tetrahedra are less stable than the [SiO 4 ] 4− tetrahedra. The higher the alkalinity, the shorter the AlO bonds and the longer the CaO bonds, thus destroying the aluminum‐oxygen ionophore. Increasing alkalinity converts complex structures into simpler ones, such as AlOAl, bringing the OAlO bond angles closer to the ideal tetrahedron. Reduced slag polymerization increases the distance between neighboring [AlO 4 ] 5− tetrahedra, thereby increasing the AlOAl bond angles. The [SiO 4 ] 4− tetrahedra prefer to bond with the [AlO 4 ] 5− tetrahedra. The change in SiOAl is less than that of SiOSi. The dissociation of CaO provides the O 2− , which allows the depolymerization of SiOSi to form nonbridging oxygen SiO, whereas the depolymerization of SiOAl occurs when alkalinity is sufficient to form the SiO and AlO bonds. The [AlO 4 ] 5− tetrahedra are more likely to bond with [AlO 4 ] 5− tetrahedra than [AlO 4 ] 5− tetrahedra.