Alkaline Processing of Uranium Ores of Indian Origin

This paper describes the R & D studies made in the development of oxidative alkaline processing schemes for the recovery of uranium from two carbonate hosted uranium ores of India namely, the Tummalapalle in Andhra Pradesh and Gogi in Karnataka. The U3O8 content of the Tummalapalle ore is about 0.04 % and that of Gogi is 0.2 %. The complexity associated with uranium mineralisation in both these ores is completely divergent. The nature of uranium mineralisation in the medium-grade Gogi ore is of simple oxide type, however the challenge lies in developing a single hydrometallurgical process scheme capable of recovering uranium present in both limestone and granite host rocks, which co-exists in the mineralised zone. Processing of Tummalapalle uranium ore is also equally formidable for a variety of reasons, chiefly, lean tenor, very-fine to ultra-fine size dissemination of uranium in gangue matrix and significant presence of reactive sulfide minerals. These challenges were addressed by minimizing the number of unit operations, incorporating regeneration and reagents-recycle loops and, adopting efficient water conservation measures. The alkaline processing of uranium ores is adopted for the first time in India and it is one amongst the few countries in the world to use this technology for the recovery of uranium from lean-tenor ores.