What are the options for an integrated IX process to recover uranium from saline and hypersaline liquors

In arid mining regions of Australia, there are significant economic and environmental drivers to utilise saline bore water as make-up water for use in uranium processing. Solvent extraction (SX) and ion exchange (IX) are the most common methods for uranium recovery from acidic leach solutions. Various studies have demonstrated the negative impact of chloride on both SX and IX processes which restricts current operating practice to < 5 g/L Cl. The focus of this paper is to discuss and propose options to broaden the operating range of chloride tolerance for IX processes beyond what is commonly practiced. ANSTO proposes two new IX processes: one to operate in saline liquors containing chloride ranging from (5-12 g/L Cl) and the second to operate in hypersaline liquors containing chloride concentrations > 15 g/L Cl. 1) The ANSTO IX process for saline liquors makes use of a weak base anion exchange resin. The process includes an uranium IX adsorption step, followed by sodium chloride elution. The eluate is treated by nanofiltration, allowing for recycle of permeate back to the elution circuit. The concentrate stream can be directly fed to a uranium precipitation circuit using hydrogen peroxide. 2) The ANSTO IX process for hypersaline liquors makes use of a chelating resin. The process includes an uranium IX adsorption step, followed by sulphuric acid elution. The eluate is treated by nanofiltration, allowing for recycle of permeate back to the elution circuit. The concentrate stream will require neutralisation and iron removal prior to uranium recovery.