It is desired to effect an approximate 100 % separation of substances A and B. The density of substance B is 7200 kg/m 3 whereas the density of substance A is 1875 kg/m 3 . The particle size distribution of A and B are shown in Table 1. The elutriating medium is water having a viscosity of 0.0015 Pa.s and a density of 1000 kg/m 3 .

Table 1 Particle Size Distribution of Substances A and B (i) Can this separation efficiency be achieved? (5 marks) (ii) If not what approximate separation efficiency can be achieved? (10 marks) Hint: The settling velocity of the smallest B particle must just exceed the settling velocity of the largest A particle if 100% separation is to be approached