Effects of B2O3 on the structure and properties of blast furnace slag by molecular dynamics simulation

ZS Bi and KJ Li and CH Jiang and JL Zhang and SF Ma and MM Sun and ZM Wang and HT Li, JOURNAL OF NON-CRYSTALLINE SOLIDS, 551, 120412 (2021).

DOI: 10.1016/j.jnoncrysol.2020.120412

B2O3 has the advantages of reducing the liquidus temperature and enhancing the fluidity of slag, while its influence mechanism in atomic scale has not yet been fully understood. Molecular dynamics simulation was conducted to investigate the influence of B2O3 on the structure and properties of SiO2-CaO-Al2O3-B2O3 blast furnace slag system at 1773 K. Results showed that a large number of SiO4(4-)-BO3(3-) structures are generated in the system after B2O3 added, Si4+ ions mainly exist in the form of SiO4(4-) tetrahedrons and B3+ ions mainly exist in the form of BO3(3-) planar triangular structures and BO4(5-) tetrahedrons. With the increase of B2O3 content, the proportion of BO3(3-) planar triangular structures increase. In addition, the content of bridge oxygen in the microstructure of slag increases obviously, the content of non-bridge oxygen decreases, and the polymerization degree of the system increases somewhat. Through the analysis of microscopic mechanism and the modified NPL viscosity model, combined with experimental data, the truth that the slag viscosity decreases with the increase of B2O3 contents were known in the simulated concentration range.

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