A method for reprocessing nitride spent nuclear fuel in molten salts comprises chlorinating the fuel in a melt of a mixture of alkali and/or alkaline earth metal chlorides containing cadmium dichloride. The chlorination is carried out in an apparatus for reprocessing nitride spent nuclear fuel using an inert gas atmosphere The apparatus has a heated zone containing a reactor with molten chlorides and nitride spent nuclear fuel submerged therein, and also a cold zone arranged under the reactor. In the chlorination process, the zone of the apparatus containing the reactor is heated to a temperature greater than 700 C., the nitride spent nuclear fuel is kept in the melt until fully chlorinated. The cold zone of the apparatus is used for crystallizing metallic cadmium which forms during the chlorination.

A method for reprocessing nitride spent nuclear fuel in molten salts comprises chlorinating the fuel in a melt of a mixture of alkali and/or alkaline earth metal chlorides containing cadmium dichloride. The chlorination is carried out in an apparatus for reprocessing nitride spent nuclear fuel using an inert gas atmosphere The apparatus has a heated zone containing a reactor with molten chlorides and nitride spent nuclear fuel submerged therein, and also a cold zone arranged under the reactor. In the chlorination process, the zone of the apparatus containing the reactor is heated to a temperature greater than 700 C., the nitride spent nuclear fuel is kept in the melt until fully chlorinated. The cold zone of the apparatus is used for crystallizing metallic cadmium which forms during the chlorination.

The present invention provides a rare-earth halide scintillating material and application thereof. The rare-earth halide scintillating material has a chemical formula of RE.sub.aCe.sub.bX.sub.3, wherein RE is a rare-earth element La, Gd, Lu or Y, X is one or two of halogens Cl, Br and I, 0a1.1, 0.01b1.1, and 1.0001a+b1.2. By taking a +2 valent rare-earth halide having the same composition as a dopant to replace a heterogeneous alkaline earth metal halide in the prior art for doping, the rare-earth halide scintillating material is relatively short of a halogen ion. The apparent valence state of a rare-earth ion is between +2 and +3. The rare-earth halide scintillating material belongs to non-stoichiometric compounds, but still retains a crystal structure of an original stoichiometric compound, and has more excellent energy resolution and energy response linearity than the stoichiometric compound.

The present invention provides a rare-earth halide scintillating material and application thereof. The rare-earth halide scintillating material has a chemical formula of RE.sub.aCe.sub.bX.sub.3, wherein RE is a rare-earth element La, Gd, Lu or Y, X is one or two of halogens Cl, Br and I, 0a1.1, 0.01b1.1, and 1.0001a+b1.2. By taking a +2 valent rare-earth halide having the same composition as a dopant to replace a heterogeneous alkaline earth metal halide in the prior art for doping, the rare-earth halide scintillating material is relatively short of a halogen ion. The apparent valence state of a rare-earth ion is between +2 and +3. The rare-earth halide scintillating material belongs to non-stoichiometric compounds, but still retains a crystal structure of an original stoichiometric compound, and has more excellent energy resolution and energy response linearity than the stoichiometric compound.

The invention provides a composition of particulate materials. The composition comprises lanthanum chloride in particulate form. The composition also comprises up to about 4% by weight of amorphous silica in particulate form, based on the combined weight of the lanthanum chloride and the amorphous silica. The addition of amorphous silica to desiccated lanthanum chloride forms a fine coating or barrier on the outer surfaces of the individual lanthanum crystals, providing a composition that is significantly more stable and able to resist coalescence of particles than pure desiccated lanthanum chloride.

The invention provides a composition of particulate materials. The composition comprises lanthanum chloride in particulate form. The composition also comprises up to about 4% by weight of amorphous silica in particulate form, based on the combined weight of the lanthanum chloride and the amorphous silica. The addition of amorphous silica to desiccated lanthanum chloride forms a fine coating or barrier on the outer surfaces of the individual lanthanum crystals, providing a composition that is significantly more stable and able to resist coalescence of particles than pure desiccated lanthanum chloride.

A method of recovering metal compounds from solid oxide fuel cell scrap includes processing the solid oxide fuel cell scrap to form a powder, digesting the processed scrap, extracting lanthanum oxide and cerium oxide from a solution containing the digested processed scrap, extracting a zirconium compound from the solution after extracting the lanthanum oxide and cerium oxide, and extracting scandium compound from the solution extracting the zirconium compound from the solution.

The present invention relates to the recovery of rare earths, scandium, niobium, tantalum, zirconium, hafnium, titanium, and the like from ores or concentrates containing fluorine. More specifically, the ores or concentrates are pretreated by carbochlorination to convert the rare earths and other metals into their chlorides and then subjected to dilute hydrochloric acid leaching to recover the valuable rare earths and other metals from the leachate. Niobium, tantalum, zirconium, hafnium, and titanium can be recovered as their chlorides or oxychlorides from the gaseous products of carbochlorination, or converted into their oxides while simultaneously regenerating chlorine.

The invention provides a method for recovering scandium from an acidic solution containing scandium. The method having [a] a precipitation step wherein sodium sulfate is added into the acidic solution containing scandium to obtain a precipitate of a scandium double sulfate; [b] a neutralization step wherein pure water is added to the precipitate of a scandium double sulfate to dissolve the precipitate of a scandium double sulfate therein, and scandium hydroxide is obtained by adding a neutralizing agent into the dissolution liquid; and [c] a re-dissolution step wherein an acid is added to the scandium hydroxide obtained in the neutralization step, so that a scandium dissolution after purification, in which the scandium hydroxide is dissolved, is obtained.

A method for extracting a rare earth metal from a mixture of one or more rare earth metals, said method comprising contacting an acidic solution of the rare earth metal with a composition which comprises an ionic liquid to form an aqueous phase and a non-aqueous phase into which the rare earth metal has been selectively extracted, wherein the ionic liquid has the formula [Ca.sup.++][X], where [X] represents a phosphinate anion.