Separation of uranium from uraniferous coaly clays using a selective ion-exchange two-step elution system

Summary An ion-exchange process for the selective separation and enrichment of uranium from the main elements Si, Al, Fe, Ca, Mg, Na, K as well as from Mo and V, which are present in uraniferous coaly clays, has been developed. After a selective carbonate leaching of the roasted ore, a 0.5 mol/l Na₂CO₃/0.5 mol/l NaHCO₃ solution was passed through the macroporous ion-exchanger AG MP-1, which at pH10 absorbed uranium quantitatively in form of a carbonato complex. Remaining absorbed amounts of Mo and V were eluted with 0.1 mol/l EDTA in 0.5 mol/l Na₂CO₃/0.5 mol/l NaHCO₃, while U was quantitatively separated by a second elution step with 0.5 mol/l HNO₃ and was afterwards precipitated with NH₄OH as a high-grade yellow cake. Differential pulse polarography (DPP), atomic absorption spectroscopy (AAS), X-ray fluorescence (XRF), instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS) had been used to determine the uranium content in the raw materials and to investigate the effectivity of the different steps of the developed process.