(a)

(b)

Figure 4: (a) Solid hold-up variation at the bottom of the vessel by increasing impeller speed, for 4 different scanning lines, impeller: RT, X: 30%, dp: 277 m, C/T: 0.33. (b) Comparison of just-suspended speed for different impellers. X: 10% wt/wt, C/T: 0.33.