Effect of B 2 O 3 on structure of CaO–Al 2 O 3 –CaF 2 –B 2 O 3 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 B_III–O–Al_IV 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.