2007 Volume 93 Issue 1 Pages 1-8
Gas injection is generally practiced in refining processes for metallurgy. The expectances for the gas injection involve the homogenization of bath temperature and compositions, and removal of second phase and dissolved impurities from molten metals.
It is widely recognized that inclusions in steel cause defects to the products. Therefore, it is important to remove inclusions from liquid steel. Solid inclusions such as alumina and silica are not wetted by the liquid steel and can be removed by attachment to gas bubbles. The attachment and removal by bubble flotation is expected as one of promising techniques on inclusion removal in liquid steel. The aim of the present work is to investigate the effects of some factors such as particle diameter, agitation speed and particle contact angle to removal rate. In this study, water model experiments have been done under turbulent flow condition using a mechanically agitated vessel. It was confirmed that the removal rate of suspended particles in liquid shows first order kinetics until 4 min in the initial stage. Furthermore, it was found that the collision frequency function has decreased with increasing agitation speed and with decreasing contact angle.