A large-particle-size ammonium uranate hydrate crystal and a method of manufacturing the same, in which the reaction rate is controlled by injecting ammonia gas into a uranyl nitrate aqueous solution, thereby increasing the particle size of the ammonium uranate hydrate crystal, and the average particle size of a final ammonium uranate hydrate crystal is 9.32 to 14.68 m, which is 100 times or more that of a conventional crystal, and uranium content is less than 1 ppm. Since this ammonium uranate hydrate crystal has a very large particle size, handling thereof in subsequent filtration, drying and calcination/reduction processes is very easy, and moreover, the design of devices for subsequent processes is simple, and little uranium is contained in the filtrate of the filtration process, thus obviating an additional chemical treatment process for uranium recovery, which can greatly reduce facility investment costs.

A multiphase composite, formed by freeze-casting, lyophilization, and sintering, has sintered particles forming a scaffold having at least one region of aligned porosity; and a second phase formed in pores of the scaffold. In a particular embodiment, the second phase is a nuclear fuel, in another, the first phase is a nuclear fuel, and in others, both phases are nuclear fuels. In some embodiments, the first phase is a ceramic, and in other embodiments a metal such as stainless steel. In other embodiments, the second phase is a metal, and in other embodiments a ceramic. In some embodiments the second phase is positioned in a subset of pores of the scaffold, at least some additional pores being filled with a third phase. In embodiments, the second phase is also sintered.

A device including an LED light source optically coupled to a green-emitting U.sup.6+-doped phosphor having a composition selected from the group consisting of U.sup.6+-doped phosphate-vanadate phosphors, U.sup.6+-doped halide phosphors, U.sup.6+-doped oxyhalide phosphors, U.sup.6+-doped silicate-germanate phosphors, U.sup.6+-doped alkali earth oxide phosphors, and combinations thereof, is presented. The U.sup.6+-doped phosphate-vanadate phosphors are selected from the group consisting of compositions of formulas (A1)-(A12). The U.sup.6+-doped halide phosphors are selected from the group consisting of compositions for formulas (B1)-(B3). The U.sup.6+-doped oxyhalide phosphors are selected from the group consisting of compositions of formulas (C1)-(C5). The U.sup.6+-doped silicate-germanate phosphors are selected from the group consisting of compositions of formulas (D1)-(D11). The U.sup.6+-doped alkali earth oxide phosphors are selected from the group consisting of formulas (E1)-(E11).

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.

A method to activate U.sub.3O.sub.8 for conversion of this uranium oxide to hydrated UO.sub.4 via reaction with hydrogen peroxide H.sub.2O.sub.2, wherein the following successive steps are performed: a) an aqueous suspension is prepared containing a powder of U.sub.3O.sub.8 and hydrogen peroxide; b) the aqueous suspension containing a powder of U.sub.3O.sub.8 and hydrogen peroxide is contacted with ozone, whereby an aqueous suspension is obtained of a powder of activated U.sub.3O.sub.8; c) optionally the powder of activated U.sub.3O.sub.8 is separated from the aqueous suspension. A method to convert U.sub.3O.sub.8 to hydrated UO.sub.4 of formula UO.sub.4, nH.sub.2O where n is 2 or 4, comprising at least one step at which hydrogen peroxide H.sub.2O.sub.2 is added to the aqueous suspension of a powder of activated U.sub.3O.sub.8 obtained at the end of step b) of the activation method or to an aqueous suspension prepared by placing in suspension in water the powder of activated U.sub.3O.sub.8 obtained at the end of step c) of the activation method.

A method to activate U.sub.3O.sub.8 for conversion of this uranium oxide to hydrated UO.sub.4 via reaction with hydrogen peroxide H.sub.2O.sub.2, wherein the following successive steps are performed: a) an aqueous suspension is prepared containing a powder of U.sub.3O.sub.8 and hydrogen peroxide; b) the aqueous suspension containing a powder of U.sub.3O.sub.8 and hydrogen peroxide is contacted with ozone, whereby an aqueous suspension is obtained of a powder of activated U.sub.3O.sub.8; c) optionally the powder of activated U.sub.3O.sub.8 is separated from the aqueous suspension. A method to convert U.sub.3O.sub.8 to hydrated UO.sub.4 of formula UO.sub.4, nH.sub.2O where n is 2 or 4, comprising at least one step at which hydrogen peroxide H.sub.2O.sub.2 is added to the aqueous suspension of a powder of activated U.sub.3O.sub.8 obtained at the end of step b) of the activation method or to an aqueous suspension prepared by placing in suspension in water the powder of activated U.sub.3O.sub.8 obtained at the end of step c) of the activation method.

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.

The present invention relates to a novel material made of uranium, gadolinium and oxygen, having a crystalline phase having cubic crystallographic structure, having an atomic ratio Gd/[Gd+U] of 0.6 to 0.93, the uranium being present in an oxidation state of +IV and/or +V. The invention further relates to the use of such a material as a consumable neutron poison of a fuel element.

The present invention relates to a novel material made of uranium, gadolinium and oxygen, having a crystalline phase having cubic crystallographic structure, having an atomic ratio Gd/[Gd+U] of 0.6 to 0.93, the uranium being present in an oxidation state of +IV and/or +V. The invention further relates to the use of such a material as a consumable neutron poison of a fuel element.

The invention relates to sulfonated aminomethylated chelate resins, to a method for producing same, to the use thereof for obtaining and purifying metals, in particular rare earth metals, from aqueous solutions and organic liquids, and for producing highly pure silicon.