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

• The B 2 O 3 -bearing slag structure was investigated with molecular dynamics. • Boron was found to form planar triangular structure with oxygen. • B 2 O 3 increase polymerization degree by increasing bridge oxygen content. • B 2 O 3 decrease slag viscosity by decreasing the stability of network structure. B 2 O 3 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 B 2 O 3 on the structure and properties of SiO 2 CaO-Al 2 O 3 -B 2 O 3 blast furnace slag system at 1773 K. Results showed that a large number of [SiO 4 ]4−-[BO 3 ]3− structures are generated in the system after B 2 O 3 added, Si4+ ions mainly exist in the form of [SiO 4 ]4- tetrahedrons and B3+ ions mainly exist in the form of [BO 3 ]3− planar triangular structures and [BO 4 ]5− tetrahedrons. With the increase of B 2 O 3 content, the proportion of [BO 3 ]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 B 2 O 3 contents were known in the simulated concentration range. [ABSTRACT FROM AUTHOR]