Wettability of non-metallic inclusions and its impact on bubble-induced flotation kinetics

Ceramic refractory bubbling devices may be applied in the steel ladle to induce the flotation of non-metallic inclusions to the slag phase. These inclusions have many origins along the steelmaking process and induce a detrimental effect on the mechanical properties of these metals. Therefore, the design of high-performance ceramic plugs relies on understanding the fundamentals of non-metallic inclusions captured by the gas bubbles. This study investigated the flotation dynamics of hydrophobic and hydrophilic hollow glass particles through experimentation using a water model and quantifying the particle concentration via light scattering. Both types of particles exhibited a comparable natural flotation removal rate, whereas a 40% increase for hydrophobic particles was observed when introducing 1.1 mm bubbles (at 25 NL/h) enhancing the efficiency from 43.1% to 65.2%. For hydrophilic particles, the efficiency increased from 59.1% to 86.2% when bubbles were injected into the system, whereas the removal rate decreased by 2.1-fold. The consequence of the practice of inert gas purging to remove non-metallic inclusions is also discussed.