1.                 Extraction of uranyl nitrate

A 20 wt% solution of uranyl nitrate (UN) in water is to be treated with tributyl phosphate (TBP) to remove 90% of the uranyl nitrate in batchwise equilibrium contacts. Assuming water and TBP are mutually insoluble, how much TBP is required for 100g of solution if, at equilibrium, (g UN/g TBP) =5.5 (g UN/g H2O) and: (a) all the TBP is used at once in one stage; (b) half is used in each of two consecutive stages; (c) two countercurrent stages are used; (d) an infinite number of crosscurrent stages is used; (e) an infinite number of countercurrent stages is used.