In alternative embodiments, the invention provides processes and methods for the recovery, removal or extracting of, and subsequent purification of uranium from a wet-process phosphoric acid using a continuous ion exchange processing approach, where the uranium is recovered from a phosphoric acid, or a phos-acid feedstock using either a dual or a single stage extraction methodology. In both cases an intermediate ammonium uranyl-tricarbonate solution is formed. In alternative embodiments, in the dual cycle approach, this solution is contacted in a second continuous ion exchange system with a strong anion exchange resin then subsequently recovered as an acidic uranyl solution that is further treated to produce an intermediate uranyl peroxide compound which is ultimately calcined to produce the final uranium oxide product. In alternative embodiments, in the single cycle case, the intermediate ammonium uranyl-tricarbonate solution is evaporated to decompose the ammonium carbonate and produce an intermediate uranium carbonate/oxide solid material. These solids are digested in an acid medium, and then processed in the same manner as the secondary regeneration solution from the dual cycle process to produce an intermediate uranyl peroxide that is calcined to produce a final uranium oxide product.

Methods and apparatus for liquid/solid separation for use in applications such as dewatering fine particulate solids, and recovery of valuable metals from ore in a leaching process are provided. One application relates to methods of agitation leaching of metals such as gold from gold-bearing feedstock. A slurry is formed in a tank by agitation, and allowed to settle. A filter bed forms to drain the liquid from the tank, and a vertical screen pipe such as a well point addresses the formation of an impervious film on the upper surface of the filter bed.

The invention relates to compounds which correspond to the general formula (I) below: ##STR00001## in which: R.sup.1 and R.sup.2 represent, independently of one another, a C.sub.4 to C.sub.12 acyclic hydrocarbon group; R.sup.3 represents H; a C.sub.1 to C.sub.12 acyclic hydrocarbon group with optionally one or more heteroatoms; a C.sub.5 or C.sub.6 cyclic hydrocarbon group; or a 5- or 6-membered heterocyclic group; R.sup.4 represents H or a C.sub.1 to C.sub.12 acyclic hydrocarbon group with optionally one or more heteroatoms; R.sup.5 and R.sup.6 represent, independently of one another, H; a C.sub.1 to C.sub.12 acyclic hydrocarbon group with optionally one or more heteroatoms; a C.sub.5 or C.sub.6 cyclic hydrocarbon group; or a 5- or 6-membered heterocyclic group; on the condition however that R.sup.5 and R.sup.6 do not each represent H. The invention also relates to the uses of these compounds as uranium(VI) ligands, in particular for extracting uranium(VI) from an aqueous solution of sulphuric acid, and also to a method that makes it possible to recover the uranium(VI) present in an aqueous solution of sulphuric acid resulting from the attack of a uranium ore by sulphuric acid and using said the compounds.

The present invention relates to a volume reduction treatment method of a spent uranium catalyst. According to the volume reduction treatment method of a spent uranium catalyst of the present invention, the disposal cost of the spent uranium catalyst can be reduced and the utilization of the repository can be improved since the method can significantly reduce the volume of the final disposal waste of the spent uranium catalyst.

Nanofiltration can be used to improve a hydrometallurgical process in which valuable metal is extracted from ore or tailings by leaching with a suitable lixiviant. The process requires at least two nanofiltration subsystems in which raffinate from a solvent extraction process is treated in a nanofiltration subsystem, after which permeate therefrom is combined with a pregnant solution stream and is treated in a second nanofiltration subsystem. This arrangement can lead to advantages in the amount of lixiviant recovered, in the raw materials required, in the effluent produced, in the size of plant, and in overall cost.

Disclosed is an apparatus that is an attrition mill for grinding or comminuting ores, mine wastes, and radioactive wastes some of which may comprise metals, which may include uranium and/or cesium and/or mercury and/or thorium and/or rare earth elements. Also disclosed are processes that employ the apparatus for combined grinding and optionally leaching metals from ores and wastes. Some such methods comprise an optional step of grinding and mixing the ore or waste with a solid inorganic base with water addition or with an aqueous inorganic base, follow by a step of grinding and mixing the ore or waste with an aqueous inorganic acid with or without leaching salt addition, to solubilize the metals present in the ore or the waste. The disclosed apparatus and methods, in some embodiments, enable efficient grinding and attrition of ores substrates and mine wastes even without need for grinding media.

Disclosed is an apparatus that is an attrition mill for grinding or comminuting ores, mine wastes, and radioactive wastes some of which may comprise metals, which may include uranium and/or cesium and/or mercury and/or thorium and/or rare earth elements. Also disclosed are processes that employ the apparatus for combined grinding and optionally leaching metals from ores and wastes. Some such methods comprise an optional step of grinding and mixing the ore or waste with a solid inorganic base with water addition or with an aqueous inorganic base, follow by a step of grinding and mixing the ore or waste with an aqueous inorganic acid with or without leaching salt addition, to solubilize the metals present in the ore or the waste. The disclosed apparatus and methods, in some embodiments, enable efficient grinding and attrition of ores substrates and mine wastes even without need for grinding media.

The disclosure relates to a beneficiation process for uranium ore comprising a hydrocyclone step that produces an underflow fraction containing uranium values for further processing and an overflow fraction containing fine particulate waste material.

The disclosure relates to a beneficiation process for uranium ore comprising a hydrocyclone step that produces an underflow fraction containing uranium values for further processing and an overflow fraction containing fine particulate waste material.

A method for extracting uranium (VI) from an aqueous solution including phosphoric acid, which includes placing the aqueous solution 5 in contact with an organic material, followed by separating the aqueous solution and the organic material. The organic material includes a solid polymer substrate impregnated with a compound having the following general formula (I):

##STR00001##

The invention also relates to a method for retrieving uranium (VI) from an aqueous solution including phosphoric acid.