Surface Tension and Related Ions Behavior of Silicate Melts of the Na2O-K2O-SiO2-CaF2 System under Ultrasonic Irradiation

Under ultrasonic irradiation, surface tension and structure of molten slags of Na2O-K2O-SiO2-CaF2 system were measured. Results showed that, the slags were degraded gradually with the increase of ultrasonic intensity and silica tetrahedron radicals with oxygen vacancies generated in the melts. In fluorine free slag, the dissociated radicals coordinate with free oxygen anions, which lead to the decrease of electrostatic force between ions and the related decrease of surface tension. While in fluorine bearing slag, the surface tension increases for the reason that the free fluorine anions dominate the behavior of coordination, which lead to the increase of electrostatic force between ions. The increase of surface tension will promote the down flow of mold flux between the gap of solidified steel shell and the mold copper wall, which will facilitate the lubrication between them.