No abstract available

No abstract available

[en] A process is described for separating uranium and thorium from an aqueous acid solution containing them together with rare earth elements. The process comprises contacting the solution with a water-immiscible organic solution of a high molecular weight primary or secondary amine whereby the uranium and thorium values are co-extracted and separating the resulting uranium and thorium loaded amine solution from the aqueous solution. The uranium and thorium are then easily separated from the loaded amine solution either by selective stripping or co-stripping and selective extraction. (Patent Office Record)

No abstract available

[en] Uranium ores, concentrates, calcines or tailings are processed to remove radium and thorium as well as uranium. Selected ores, concentrates or tailings, or if more appropriate, chlorination calcines thereof, are leached by selected aqueous chlorinecontaining media (preferably in two stages) until uranium, radium and thorium are substantially all dissolved, with the insoluble residual solids being suitable for disposal. The leach solution is treated to recover sequentially uranium, usually thorium, and radium by selected techniques. The radium recovered can be disposed of in any environmentally-acceptable manner. The amount of iron in the residual leach liquor should be controlled to avoid iron build-up, with the barren leach solution being suitable for recycle

[en] The authors have developed a complete method of recovering separately uranium, thorium and radium from impure solids such as ores, concentrates, calcines or tailings containing these metals. The technique involves leaching, in at least one stage. The impure solids in finely divided form with an aqueous leachant containing HCl and/or Cl₂ until acceptable amounts of uranium, thorium and radium are dissolved. Uranium is recovered from the solution by solvent extraction and precipitation. Thorium may also be recovered in the same manner. Radium may be recovered by at least one ion exchange, absorption and precipitation. This amount of iron in the solution must be controlled before the acid solution may be recycled for the leaching process. The calcine leached in the first step is prepared in a two stage roast in the presence of both Cl₂ and a metal sulfide. The first stage is at 350-450⁰ and the second at 550-700⁰

No abstract available

No abstract available

[en] An hydrochloric acid leaching process has been found to provide high uranium recoveries and low residual radium content in the tailings. Several uranium extraction process flowsheets have been developed based on hydrochloric acid leaching of uranium ores, of pyrite-free tails from pyrite flotation minerals and of magnetic concentrates from high intensity magnetic separation of radioactive minerals. Two-stage hydrochloric acid leaching of an Elliot Lake uranium ore with 4-hr. retention in each stage provided 98% overall recovery of uranium and tailings containing 30 pCi g^-1 Ra. However, the economics of the acid chloride process compares unfavourably both in capital and in operating costs with the conventional sulphuric acid process, unless such a process provides significant savings in environmental costs. (orig.)

[en] This paper describes the development and application of single-stage fluidized bed continuous ion exchange to the following processes: removal of base metals from mine water; cyanide removal from gold mill waste; uranium removal from sulphuric acid leach liquor; and uranium removal from mine water. (auth)