The present invention provides a method of preparing a positive electrode active material for a secondary battery including preparing a first transition metal-containing solution including a nickel raw material, a cobalt raw material, and a manganese raw material and a second transition metal-containing solution including a nickel raw material, a cobalt raw material, and a manganese raw material in a concentration different from that of the first transition metal-containing solution; preparing a reaction solution, in which nickel manganese cobalt-based composite metal hydroxide particles are formed, by adding an ammonium cation-containing complexing agent and a basic compound as well as the second transition metal-containing solution to the first transition metal-containing solution and performing a co-precipitation reaction in a pH range of 11 to 13.

A nickel composite hydroxide containing reduced amounts of sulfate radicals and chlorine as impurities. The nickel composite hydroxide is represented by Ni.sub.1-x-yCo.sub.xAl.sub.y(OH).sub.2+(0.05x0.01y0.2, x+y<0.4, and 0<0.5), and includes spherical secondary particles formed by aggregation of plurality of plate-shaped primary particles, secondary particles have an average particle diameter of 3-20 m, sulfate radical content of 1.0 mass % or less, chlorine content of 0.5 mass % or less, and carbonate radical content of 1.0-2.5 mass %. The nickel composite hydroxide is obtained by a process including a crystallization step in which crystallization is performed in reaction solution obtained by adding alkali solution to aqueous solution containing mixed aqueous solution containing nickel and cobalt, ammonium ion supplier, and aluminum source. The alkali solution is mixed aqueous solution of alkali metal hydroxide and carbonate, and ratio of carbonate to alkali metal hydroxide in mixed aqueous solution represented by [C0.sub.3.sup.2]/[OH.sup.]=0.002 or more but 0.050 or less.

A filling material for a resin composition includes a base material and a coating material coating at least a portion of a surface of a particle of the base material. The base material comprises a first inorganic compound containing a Group II element. The coating material comprises a second inorganic compound containing the Group II element and is different from the first inorganic compound. A method of manufacturing the filling material is provided. A resin composition comprising the filling material, a package, a light-emitting device, and methods of manufacturing them are also provided.

The present invention relates to a method for removing radioactive element thorium in a rare earth mineral, comprising: mixing the rare earth mineral with selenium dioxide in water, reacting radioactive element thorium with selenium dioxide by hydrothermal method, cooling to form a crystal, and separating the crystal to remove the radioactive element thorium. In the invention, tetravalent element thorium is selectively bound to inorganic ligand selenium dioxide in a hydrothermal environment to form a crystal, thereby achieving removal of radioactive element thorium. The method has high crystallization rate and high decontamination efficiency, and removes thorium from trivalent lanthanide element by crystallization solidification under a uniform reaction condition. Compared to a conventional industrial method for thorium separation, the method has low energy consumption and high separation ratio, enables one-step solidification separation, and effectively avoids the disadvantages of redundant separation operations and a large amount of organic and radioactive liquid wastes.

A composition of matter is provided, including anhydrite calcium sulfate whiskers having a mean aspect ratio of at least 30. Another composition of matter is provided, including alpha-derived anhydrite calcium sulfate whiskers. Yet another composition of matter is provided, including fine alpha particle-derived anhydrite calcium sulfate whiskers.

Monodisperse particles having: a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology are disclosed. Due to their uniform size and shape, the monodisperse particles self assemble into superlattices. The particles may be luminescent particles such as down-converting phosphor particles and up-converting phosphors. The monodisperse particles of the invention have a rare earth-containing lattice which in one embodiment may be an yttrium-containing lattice or in another may be a lanthanide-containing lattice. The monodisperse particles may have different optical properties based on their composition, their size, and/or their morphology (or shape). Also disclosed is a combination of at least two types of monodisperse particles, where each type is a plurality of monodisperse particles having a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology; and where the types of monodisperse particles differ from one another by composition, by size, or by morphology. In a preferred embodiment, the types of monodisperse particles have the same composition but different morphologies. Methods of making and methods of using the monodisperse particles are disclosed.

Electrochemical cell comprising an anode and a cathode is provided. The anode and the cathode independently comprises or consists essentially of a vanadium oxide compound having general formula M.sub.nV.sub.6O.sub.16, wherein M is selected from the group consisting of ammonium, alkali-metal, and alkaline-earth metal; and n is 1 or 2. Method of preparing a vanadium oxide compound having general formula M.sub.nV.sub.6O.sub.16 is also provided.

The disclosure relates to a device for continuously producing qualitatively high-grade crystalline silicon carbide, in particular in the form of nanocrystalline fiber.

The present invention provides a positive electrode active material for a secondary battery, which includes a core, a shell disposed to surround the core, and a buffer layer which is disposed between the core and the shell and includes pores and a three-dimensional network structure connecting the core and the shell, wherein, the core, the shell, and the three-dimensional network structure of the buffer layer each independently include a lithium nickel manganese cobalt-based composite metal oxide and at least one metallic element of the nickel, the manganese, and the cobalt has a concentration gradient that gradually changes in any one region of the core, the shell, and the entire positive electrode active material.

It is an object of the present disclosure to provide a method for inexpensively producing a high-performance barium sulfate powder which is obtained by using inexpensive barium sulfide as a raw material, has a high whiteness degree, and can suppress the generation of volatile components. A method for producing a barium sulfate powder comprises a step of heat treating a raw barium sulfate powders obtained by using barium sulfide as a raw material at 600 to 1300 C., wherein a retention time X (minutes) at a heat treatment temperature of t C. is more than time expressed by the following general formula: X (minutes)=A10.sup.6e.sup.(0.015t), where A is 8 or more, and an upper limit of X is 3000 minutes in the formula.