A cyclone's performance is being assessed, but the feed is inaccessible and so it is the underflow and overflow streams that are measured. The size distribution of each stream is measured by placing a representative sample into the top of a stack of sieves. The following table gives the mass retained on each of the sieve screens (i.e. the mass is the amount of material larger than the corresponding size and smaller than the size above). Mass on sieve Sieve size Underflow Overflow microns g g 212 0 0 150 37 5 105 25 11 74 14 24 53 12 34 Undersize 16 56 104 190 The measure mass flowrate to the underflow is 24 t/hr and the overflow is 35 t/hr. a) What is the mass recovery to the underflow? b) Calculate the cumulative size distributions of the underflow and overflow. The performance can be assessed using partition numbers. c) Calculate all the partition numbers and their corresponding representative sizes. d) What is the d50 and bypass ratio? You have enough information to calculate the size distribution of the feed. e) Calculate the cumulative size distribution of the feed. **** (2) (4) (5) 52 (2) (4) It is often not possible to measure the flow rates of all streams that you might wish to. Around one cyclone only the flow rate of the underflow can be measured directly, but the density of all the streams can be measured quite easily. The measured total flow rate (water and solid) of the underflow is 35 tph. The feed slurry has an SG of 1.8, the underflow an SG of 2.0 and the overflow an SG of 1.6. The SG of the solids is 2.5. f) Calculate the mass percent solids in each of the streams. g) What is the mass flow rate of the feed and overflow? 35 (3) (5)