Effect of B2O3 on structure of CaO–Al2O3–CaF2–B2O3 molten slag using molecular dynamics simulation

Abstract

To investigate the influence of B2O3 on the microstructure of the CaO–Al2O3–CaF2 slag, molecular dynamics were employed. Various performance parameters such as radial distribution functions, coordination numbers, oxygen distribution, and Q n distributions were considered. The results indicate that Al3+ predominantly adopts a [AlO4]5– tetrahedral structure within the slag, with a minority of Al3+ existing in the forms of [AlO5]7– and [AlO6]9–. B3+ primarily manifests as a [BO3]3– planar triangular structure in the CaO–Al2O3–CaF2 slag. The microstructure of the CaO–Al2O3–CaF2 slag is characterised by a simple network of Al–O–F. The addition of B2O3 content in the slag promotes the incorporation of [BO3]3– into the O–Al–F simple network, thereby displacing F– ions, and leading to the emergence of a substantial amount of complex BIII–O–AlIV network structures within the Al–O–F simple network. This leads to an increase in the degree of polymerisation of the slag structure. Furthermore, the viscosity of slag system increases.