(a) The distribution coefficient (D) for the extraction of Zn(II) by 20% (v/v) Cyanex-302 (which may be denoted by RH) in kerosene in a laboratory test conducted at pH1, temperature 50C and aqueous/organic volume ratio 1/1 is 1.35. Calculate the %Zn (II) extraction after three stages of (i) cross current, (ii) counter current, operations. [8 marks] (b) The loading of Cu (II) onto a cation exchange resin (RH) can be expressed by the reaction: RH2+Cu2+=RCu+2H+ (i) The equilibrium concentrations of Cu (II) in resin (q) and solution (c) can be related to the maximum resin loading of Cu(II)(Q) and the cquilibrium constant (K) by the equation given below. Briefly explain how you would determine the values of K and Q using a graphical method. q=cK+[H+]2cKQ [6 marks] (ii) Copper(II) is to be recovered from a heap leach liquor containing 1g/L Cu(II) at pH 1.5 by passing the liquor through a bed of resin RH2 packed in a column. Estimate the equilibrium loading of copper on the resin that could be achieved by this procedure. Assume K=1.7 and Q =58.7g/L at ambient temperature. [8 marks] (iii) Propose a stripping agent for copper with reasons. [3 marks] c) The selectivity coefficients of a weak acid chelating resin for selected metal ions are listed below. List the steps that you would take to separate Cu(II) from a heap leach liquor containing Cu(II) and Fe( III) at pH 1.5. [5 marks]