Water model study on inclusion removal from liquid steel by bubble flotation under turbulent conditions

Abstract

Inclusion removal from liquid steel by bubble flotation under turbulent conditions is analysed using a water model. Turbulence is realised by impeller stirring in a water containing vessel. First, the effects of variables such as filter pore size, gas flowrate, NaCl concentration, and stirring intensity on bubble size are investigated. Second, particle removal by bubble flotation is studied using the water containing vessel system. The results indicate that particle removal rate by bubble flotation is controlled by non-first order kinetics. The factors affecting the particle removal rate constant k ₁ are discussed and a final empirical equation is derived as follows: -dc/dt = k ₁ c^1·3665 and k ₁ = A(d _p/d _B)^{2·65ϵ0·104} Q _g^1·630, where c is particle number density, t is time, A is a constant parameter, d _p and d _B are the particle and bubble diameter respectively, ϵ is the turbulent energy dissipation rate, and Q _g is the gas flowrate.