Dual-Temperature Ion-Exchange Separation of Copper and Zinc by Different Techniques

Abstract

Separation of copper from zinc-containing acidic solutions has been advanced by different techniques of dual-temperature ionexchange fractionation on iminodiacetic resin Amberlite IRC 718. Cycling-zone adsorption and parametric pumping (using single-column as well as double-column set-ups) experiments have been carried out in fixed-bed ion-exchange column. Measurement of equilibrium characteristics of the resin-solution system has shown that separation results from the variation of the ions sorbability with temperature. It has been found that temperature variation leads to reverse of selectivity between copper and hydrogen ions. Cycling-zone adsorption technique has allowed the copper content to be decreased up to 4 times in the resin phase and increased up to 1.7 times in the effluent when carrying out the process at 80 and 20 °C, respectively. The copper concentration has been decreased 4.4 fold after 9 treatment cycles of solution aliquot (15 BV) by single-column mode of the parametric pumping method. Two steps of the fractionation process (loading and elution) have been performed by continuous mode of operation in two counter-current columns. Continuous separation is preferred over fixed-bed column techniques. The steady-state sorption fronts have been formed on both stages of the process due to the reverse of selectivity mentioned above.