DUAL-TEMPERATURE ION-EXCHANGE SEPARATION OF COPPER AND ZINC BY DIFFERENT TECHNIQUES

Separation of copper from zinc-containing acidic solutions has been ad vanced by different techniques of dual-temperature ion-exchange fracti onation on iminodiacetic resin-Amberlite IRC 718. Cycling-zone adsorpt ion and parametric pumping (using single-column as well as double-colu mn set-ups) experiments have been carried out in fixed-bed ion-exchang e column. Measurement of equilibrium characteristics of the resin-solu tion system has shown that separation results from the variation of th e ions sorbability with temperature. It has been found that temperatur e variation leads to reverse of selectivity between copper and hydroge n ions. Cycling-zone adsorption technique has allowed the copper conte nt to be decreased up to 4 times in the resin phase and increased up t o 1.7 times in the effluent when carrying out the process at 80 and 20 degrees C, respectively. The copper concentration has been decreased 4.4 fold after 9 treatment cycles of solution aliquot (15 BV) by singl e-column mode of the parametric pumping method. Two steps of the fract ionation process (loading and elution) have been performed by continuo us mode of operation in two counter-current columns. Continuous separa tion is preferred over fixed-bed column techniques. The steady-state s orption fronts have been formed on both stages of the process due to t he reverse of selectivity mentioned above.