The samples were dispersed in water at four different solid concentrations C, i.e., 23.1, 37.5, 42.9 and 50.0 wt.%; and these slurries were used as starting samples.Viscosity of the slurry was measured at 300K by using a rotational viscometer (VISCOTESTER, VT-03; RION) as given in Table 2.The fraction of critical speed N/N C was varied from 0.8 to 1.8, where N and N …