MODELING THE BINARY ADSORPTION OF GOLD AND ZINC CYANIDES ONTO A STRONG-BASE ANION-EXCHANGE RESIN

The binary adsorption of gold cyanide and zinc cyanide onto a strong-base anion exchange resin is studied. The empirical Fritz and Schluender (1974) binary isotherm was found to fit the experimentally measured equilibrium data well. It is shown that small amounts of zinc cyanide in solution cause a large drop in equilibrium loading of gold cyanide. Previously measured gold and zinc loading profiles inside the resin particles were compared with a binary version of the homogeneous surface diffusion model and found to be in broad agreement. Both the model and the experimental results demonstrate that the gold initially loads more rapidly than the zinc, but that it reaches a maximum loading after which the gold loading decreases as it is eluted by the zinc.