Developing a mini pilot resin in solution Process for adsorption of uranium in Pachuca reactors (case study: Saghand uranium ore of the Central Iran)

Abstract

Resin in pulp, as the most frequently employed process for extraction of uranium from low-grade ores, encounters difficulties when the pulp contains dense or abrasive minerals, e.g., Saghand ores in central Iran. To overcome these complications, it was suggested to remove solid content of the pulp at first, and inject the clear solution into a cascade of Pachuca reactors, where uranium is adsorbed by an anion exchanger such as Varion-AP. We made two mini pilot cascades, each comprising ten Pachuca reactors, to check both co-current and countercurrent resin in solution processes on the Saghand leach liquor. The countercurrent scheme, having a higher efficiency, was able to adsorb 99% of uranium from a 238 mg/L solution, with 7 stages, at optimum pH = 1.8. Kinetics of adsorption was controlled by intra-particle diffusion, and a generalized Glueckauf model, fairly well described multistage adsorption. The most significant process variable was found to be flow rate of the resin, whose precise adjustment, results in the optimum process design, where the net present value (NPV) becomes minimum.