Abstract: The present invention provides a clathrate compound which can be used as a thermoelectric material, a hard material, or a semiconductor material. Silicon or carbon are formed into a clathrate lattice, and a clathrate compound is then formed in which specified doping atoms are encapsulated within the clathrate lattice, and a portion of the atoms of the clathrate lattice are substituted with specified substitution atoms. The clathrate lattice is, for example, a silicon clathrate 34 (Si34) mixed lattice of a Si20 cluster including a dodecahedron of Si atoms, and a Si28 cluster including a hexahedron of Si atoms. Suitable doping atoms are atoms from group 1A, group 2A, group 3A, group 1B, group 2B, group 3B, group 4A, group 5A, group 6A, and group 8, and suitable substitution atoms are atoms from group 1A, group 2A, group 3A, group 1B, group 2B, group 3B, group 5A, group 6A, group 7A, group 5B, group 6B, group 7B, and group 8 of the periodic table.

Abstract: This is a pyroprocess for processing spent nuclear fuel. The spent nuclear fuel is chopped into pieces and placed in a basket which is lowered in to a liquid salt solution. The salt is rich in ZrF4 and containing alkali or alkaline earth fluorides, and in particular, the salt chosen was LiF-50 mol % ZrF4 with a eutectic melting point of 500° C. Prior to lowering the basket, the salt is heated to a temperature of between 550° C. and 700° C. in order to obtain a molten solution. After dissolution the oxides of U, Th, rare earth and other like oxides, the salt bath solution is subject to hydro-fluorination to remove the oxygen and then to a fluorination step to remove U as gaseous UF6. In addition, after dissolution, the basket contains PuO2 and undissolved parts of the fuel rods, and the basket and its contents are processed to remove the Pu.

Abstract: Precious metal values, e.g., platinum, palladium and rhodium, and, optionally, other valuable elements, e.g., one or more rare earths and cerium in particular, are recovered from a wide variety of compositions of matter and articles of manufacture, for example waste or spent catalysts such as vehicular postcombustion catalysts, by (i) optionally comminuting such composition/article into a finely divided state, (ii) intimately admixing the composition/article with sulfuric acid, (iii) calcining the resulting admixture at a temperature ranging from 150° to 450° C., and (iv) leaching the calcined admixture in an aqueous medium, whether simultaneously or separately, with H+ ions and chloride ions, whereby obtaining (1) a solid residue substantially depleted of such precious metal values and, optionally, of such other elements, and (2) at least one liquid solution comprising such precious metal values and, optionally, such other elements.

Abstract: A method and apparatus for removing metal contaminants from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents may be added to precipitate the metal oxide and/or the metal as either metal oxide, metal hydroxide, or as a salt. The precipitated materials are filtered, dried and packaged for disposal as waste or can be immobilized as ceramic pellets. More than about 90% of the metals and mineral residues (ashes) present are removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be spray-dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 1.0 ppm of contaminants.

Abstract: Disclosed is a positive active material for a rechargeable lithium battery. The positive active material includes at least one compound represented by formulas 1 to 4 andl a metal oxide or composite metal oxide layer formed on the compound.

Abstract: A photocatalyst is provided consisting of TiO2 doped with at least one lanthanide metal oxide. The photocatalyst may be prepared by forming a titanium-containing gel and then drying the gel and subjecting it to calcinations. The photocatalyst may be used in photodegradation of organic material.

Abstract: The present invention provides an alkaline storage battery excellent in high-rate charge and discharge characteristics, and a hydrogen-absorbing alloy electrode suitable for the battery and a method for producing the same. The hydrogen-absorbing alloy is preferably produced by wet grinding in water a hydrogen-absorbing alloy comprising at least one rare earth element, nickel and at least one transition metal element, treating the resulting alloy powders in an aqueous alkali solution, and then consecutively treating the powders in an acidic aqueous solution. The hydrogen-absorbing alloy powders have a structure of a nickel-condensed layer being exposed and have many pores.

Abstract: Oxygen sensitive resistance materials for use with oxygen sensors, in particular &lgr; probes are described. These materials are based on the fact that with complex metal oxides it is possible—by adding suitable doping substances—to achieve a negligible temperature dependence of the electric resistance of these materials for different oxygen partial pressures and to preset it to a desired partial pressure value.

Abstract: A hydrothermal method for forming nanoparticles of a rare earth element, oxygen and fluorine has been discovered. Nanoparticles comprising a rare earth element, oxygen and fluorine are also described. These nanoparticles can exhibit excellent refractory properties as well as remarkable stability in hydrothermal conditions. The nanoparticles can exhibit excellent properties for numerous applications including fiber reinforcement of ceramic composites, catalyst supports, and corrosion resistant coatings for high-temperature aqueous solutions.

Abstract: The invention comprises a borosilicate retention aid composition and a method for improving the production of paper by addition of the borosilicate. The borosilicate may be utilized in conjunction with a high molecular weight synthetic flocculant and/or starch, with or without the addition of a cationic coagulant. The borosilicate material is preferably a colloidal borosilicate. Methods for the preparation of the borosilicate material are disclosed.

Abstract: The invention comprises a borosilicate retention aid composition and a method for improving the production of paper by addition of the borosilicate. The borosilicate may be utilized in conjunction with a high molecular weight synthetic flocculant and/or starch, with or without the addition of a cationic coagulant. The borosilicate material is preferably a colloidal borosilicate. Methods for the preparation of the borosilicate material are disclosed.

Abstract: The present invention is an improvement to the method of separating and purifying gadolinium from a mixture of gadolinium and europium having the steps of (a) dissolving the mixture in an acid; (b) reducing europium+3 to europium+2; and (c) precipitating the europium+2 with a sulfate ion in a superstoichiometric amount; wherein the improvement is achieved by using one or more of the following: (i) the acid is an anoic acid; (ii) the reducing is with zinc metal in the absence of a second metal or with an amount of the second metal that is ineffective in the reducing; (iii) adding a group IIA element after step (c) for precipitating the excess sulfate prior to repeating step (c); (iv) the sulfate is a sulfate salt with a monovalent cation; (v) adding cold europium+3 prior to repeating step (c).

Abstract: Proposed is an improvement in a multi-stage solvent extraction process of a metal value such as rare earth elements from an acidic feed solution containing the metal value in the form of a water-soluble salt by bringing the aqueous solution into contact with a water-immiscible organic extractant solution containing an extractant compound which releases an acid when combined with the metal ions.

Abstract: The present invention concerns a sulfide of a rare earth and an alkali, a process for its preparation and its use as a colored pigment. The sulfide is characterized in that it has the formula ABS2 where A represents at least one alkali and B represents at least one rare earth and in that it is constituted by grains with an average size of 1.5 &mgr;m at most. The preparation process for the sulfide is characterized in that at least one rare earth carbonate or hydroxycarbonate is brought into the presence of at least one gas selected from hydrogen sulfide or carbon disulfide. The product obtained is optionally deagglomerated. The sulfide can be used as a pigment in plastics, paints, finishes, rubbers, ceramics, glazes, paper, inks, cosmetics, dyes, laminated coatings and materials based on or obtained from at least one inorganic binder.

Abstract: Hafnium is recovered from irradiated tantalum by: (a) contacting the irradiated tantalum with at least one acid to obtain a solution of dissolved tantalum; (b) combining an aqueous solution of a calcium compound with the solution of dissolved tantalum to obtain a third combined solution; (c) precipitating hafnium, lanthanide, and insoluble calcium complexes from the third combined solution to obtain a first precipitate; (d) contacting the first precipitate of hafnium, lanthanide and calcium complexes with at least one fluoride ion complexing agent to form a fourth solution; (e) selectively adsorbing lanthanides and calcium from the fourth solution by cationic exchange; (f) separating fluoride ion complexing agent product from hafnium in the fourth solution by adding an aqueous solution of ferric chloride to obtain a second precipitate containing the hafnium and iron; (g) dissolving the second precipitate containing the hafnium and iron in acid to obtain an acid solution of hafnium and iron; (h) selectively ad

Abstract: An improved process for the beneficiation of mixtures of mineral particles (such as kaolin clays) containing minerals which chelate with hydroxamates. The use of a silicon-containing compound in combination with a hydroxamate results in a more effective separation of minerals which chelate with the hydroxamate.