Terminal Settling Velocity of Particle in Suspension

In the steelmaking process, most slags and fluxes often contain a solid phase, such as CaO. The suspension in which solid phases are suspended has higher viscosity than that of a pure matrix liquid. Therefore, it is expected that the viscosity of slag containing solid phases will increase. In this study, the terminal settling velocity of particles in a suspension has been measured. The suspensions consist of a silicone oil matrix and polyethylene beads, and the settling particles are bearing balls made of stainless steel. As a result of the higher viscosity of suspension, the terminal settling velocity of the bearing ball becomes slower than that in the pure silicone oil. It was clarified that the retardation of the terminal velocity and the increase in the drag coefficient depend only on the volume fraction of the solid phase (polyethylene beads) of the suspension, and they are independent of the size of the suspended beads and the viscosity of the matrix liquid. A correlation equation for predicting the drag coefficient of particles in a suspension was proposed.