Separation of gold from iodine-iodide solutions by cementation on zinc particles was studied. The effect of various parameters such as mixing rate, temperature, zinc particles size, and initial concentrations of gold-iodide complex and iodine were examined. The reaction was found to be under diffusion control at the conditions studied. Due to iodine side reactions, excess zinc consumption and a subsequent retardation of the cementation reaction rate were identified. A well-defined, conventional first-order kinetics model was established to explain the experimental findings.