The influence of solid particles size

density and loading on the critical gas-inducing impeller speed was investigated in a gas-liquid-solid stirring tank equipped with a hollow Rushton impeller. Three types of solid particles

hollow glass beads with diameters of 300 μm

200 μm

100 μm

and 60 μm

silica gel and desalting resin

were used. It was found that the adding solid particles would change the critical impeller speed. For hollow glass beads and silica gel

whose relative densities were less than or equal to 1.5

the critical impeller speeds increased with the solid loading before reaching the maximum values

and then decreased to a value even lower than that without added solids. The size of the solids also had apparent influence on the critical impeller speed

and larger solid particles correspond to a smaller critical impeller speed. The experimental data also showed that the gasinducing was beneficial to the suspension of the solid particles.