Novel dissymmetric N,N-dialkylamides which meet the following formula (I):

##STR00001##

where R represents a linear or branched alkyl group at C.sub.8 to C.sub.15. A method for synthesizing these N,N-dialkylamides, and to the uses of same as extractants, alone or in admixture, in order to extract uranium and/or plutonium from an aqueous acid solution, or to totally or separate uranium from plutonium from an aqueous acid solution and, in particular, an aqueous solution resulting from dissolving spent nuclear fuel in nitric acid. Further, a method for processing an aqueous solution resulting from the dissolution of a spent nuclear fuel in nitric acid, allowing the uranium and plutonium contained in the solution to be extracted, separated and decontaminated in a single cycle, without requiring any plutonium reduction operation, and in which one of the aforementioned N,N-dialkylamides or a mixture of same is used as extractant. Applications for the method include the processing of spent nuclear fuels, in particular comprising uranium (e.g. UOX) or uranium and plutonium (e.g. MOX).

A method for the treatment of an aqueous solution resulting from the dissolution of a spent nuclear fuel in nitric acid, allowing the uranium and plutonium contained in the solution to be extracted, separated and decontaminated in a single cycle, without requiring any operation involving a reductive stripping of plutonium. Applications for the method include the processing of uranium-based and/or plutonium-based spent nuclear fuels.

The above mentioned invention describes a process for producing uranium and/or at least one rare earth element selected from the group consisting of cerium, dysprosium, erbium, europium, gadolinium, holmium, lanthanum, lutetium, neodymium, praseodymium, promethium, samarium, scandium, terbium, thulium, ytterbium and yttrium out of an ore. The ore is mixed with sulphuric acid with an concentration of at least 95 wt.-% to a mixture, wherein the mixture is granulated to pellets. The pellets are fed into at least one fluidized bed fluidized by a fluidizing gas for a thermal treatment at temperatures between 200 and 1000 C. The at least one fluidized bed is developed such that it at least partly surrounds a gas supply tube for a gas or a gas mixture fed into the reactor and the gas or gas mixture is used as a heat transfer medium.

The present disclosure relates to a process and system for recovery of one or more metal values using solution extraction techniques and to a system for metal value recovery. In an exemplary embodiment, the solution extraction system comprises a first solution extraction circuit and a second solution extraction circuit. A first metal-bearing solution is provided to the first and second circuit, and a second metal-bearing solution is provided to the first circuit. The first circuit produces a first rich electrolyte solution, which can be forwarded to primary metal value recovery, and a low-grade raffinate, which is forwarded to secondary metal value recovery. The second circuit produces a second rich electrolyte solution, which is also forwarded to primary metal value recovery. The first and second solution extraction circuits have independent organic phases and each circuit can operate independently of the other circuit.

The application relates to a method for separating iron from an initial liquid organic phase containing uranium and iron, wherein the initial liquid organic phase is contacted with an aqueous solution referred to as aqueous de-ironing solution, whereby the iron passes into the aqueous solution to form a final liquid aqueous phase, and uranium remains in the initial liquid organic phase to form a final liquid organic phase referred to as de-ironed organic phase. The method is characterised in that the aqueous de-ironing solution contains an inorganic acid and uranium, and does not contain iron. The application also relates to a method for extracting uranium from an aqueous solution of an inorganic acid containing uranium and iron.

A solution for leaching metals from clay containing ore and a method of leaching ore is described. The solution comprises a cyanide; a wetting agent; and a clay stabilizing polymer.

The invention relates to the use of an organic-inorganic hybrid material, comprising an inorganic solid support on which are grafted organic molecules having the general formula (I) below: ##STR00001##
in which: x, y and z=0 or 1, with at least one of x, y and z different from 0; m=1 to 6; v and w=0 or 1, with v=1 when w=0, and v=0 when w=1; if x=0, R.sup.1H or a saturated or unsaturated, linear or branched, C.sub.1 to C.sub.12 hydrocarbon group, whereas, if x=1, R.sup.1=a group bound to the inorganic solid support by at least one covalent bond; if y=0, R.sup.2H or a saturated or unsaturated, linear or branched, C.sub.1 to C.sub.12 hydrocarbon group, whereas, if y=1, R.sup.2=a group bound to the inorganic solid support by at least one covalent bond; if z=0, R.sup.3H or a saturated or unsaturated, linear or branched, C.sub.1 to C.sub.12 hydrocarbon group, whereas, if z=1, R.sup.3=a group bound to the inorganic solid support by at least one covalent bond; R.sup.4 and R.sup.5H, a saturated or unsaturated, linear or branched, C.sub.2 to C.sub.8 hydrocarbon group, or a monocyclic aromatic group;
for extracting uranium(VI) from a sulfuric acid aqueous solution. The invention also relates to a method that makes it possible to recover the uranium(VI) present in a sulfuric acid aqueous solution, selectively with respect to the other metal cations that may also be present in said solution.

A process for selectively separating a metallic constituent from other metals and other materials accompanying the metallic constituent in a mixture is described. The process comprises the step of providing the mixture in an aqueous solution such that the metallic constituent forms a complex anion in the solution. One or more of the other metals forms a cation or a complex cation in the solution. Another step includes contacting the solution with one or more additives to form layered double hydroxide (LDH) material in situ such that the complex anion is intercalated within interlayers of the LDH material and wherein one or more of the other metals are incorporated into the LDH material's crystal structure or matrix. Another step involves the addition of an LDH to an aqueous solution. The process involves selectively recovering the metallic constituent from the interlayer of the LDH by subjecting the LDH to a recovery treatment step(s) and as required, methods to modify the LDH to facilitate metal separation and recovery or contaminant stabilisation.

A process for selectively separating a metallic constituent from other metals and other materials accompanying the metallic constituent in a mixture is described. The process comprises the step of providing the mixture in an aqueous solution such that the metallic constituent forms a complex anion in the solution. One or more of the other metals forms a cation or a complex cation in the solution. Another step includes contacting the solution with one or more additives to form layered double hydroxide (LDH) material in situ such that the complex anion is intercalated within interlayers of the LDH material and wherein one or more of the other metals are incorporated into the LDH material's crystal structure or matrix. Another step involves the addition of an LDH to an aqueous solution. The process involves selectively recovering the metallic constituent from the interlayer of the LDH by subjecting the LDH to a recovery treatment step(s) and as required, methods to modify the LDH to facilitate metal separation and recovery or contaminant stabilisation.

Protactinium, actinium, radium, radiolanthanides and other radionuclide fission products were separated and recovered from a proton-irradiated thorium target. The target was dissolved in concentrated HCl, which formed anionic complexes of protactinium but not with thorium, actinium, radium, or radiolanthanides. Protactinium was separated from soluble thorium by loading a concentrated HCl solution of the target onto a column of strongly basic anion exchanger resin and eluting with concentrated HCl. Actinium, radium and radiolanthanides elute with thorium. The protactinium that is retained on the column, along with other radionuclides, is eluted may subsequently treated to remove radionuclide impurities to afford a fraction of substantially pure protactinium. The eluate with the soluble thorium, actinium, radium and radiolanthanides may be subjected to treatment with citric acid to form anionic thorium, loaded onto a cationic exchanger resin, and eluted. Actinium, radium and radiolanthanides that are retained can be subjected to extraction chromatography to separate the actinium from the radium and from the radio lanthanides.