Rare earth compound particles are prepared by a step of heating an aqueous solution containing rare earth metal ions and urea to form a rare earth compound by a reaction of a hydrolysis product of urea, and the rare earth metal ions. In the heating step, heating the aqueous solution into which an acetylene glycol-ethylene oxide adduct is added.

Rare earth compound particles are prepared by a step of heating an aqueous solution containing rare earth metal ions and urea to form a rare earth compound by a reaction of a hydrolysis product of urea, and the rare earth metal ions. In the heating step, heating the aqueous solution into which an acetylene glycol-ethylene oxide adduct is added.

Disclosed is a method for processing ash, particularly fly ash, in which method several elements are separated from the ash. In the method both noble metals and rare earth elements are separated.

A method for extracting and separating rare earth elements comprising providing a rare earth-containing ore or tailings, grinding the rare earth-containing ore to form powdered ore; leaching the powered ore with at least one mineral acid, forming a leach solution comprising at least one metal ion, rare earth elements and a solid material, separating the solid material from the leach solution to form aqueous-metal concentrate, precipitating the aqueous-metal concentrate to selectively remove the metal ion from the leach solution and obtain a precipitate of the rare earth elements; heating the precipitate of the rare earth elements in air to form oxide of the rare earth elements, mixing the oxide of the rare earth elements with an ammonium salt and heating in a dry air/nitrogen, forming a mixture of anhydrous rare earth salts in an aqueous solution, and separating the rare earth elements from the aqueous solution by means of an electrowinning process.

The present invention provides a rare earth cold accumulating material particle comprising a rare earth oxide or a rare earth oxysulfide, wherein the rare earth cold accumulating material particle is composed of a sintered body; an average crystal grain size of the sintered body is 0.5 to 5 μm; a porosity of the sintered body is 10 to 50 vol. %; and an average pore size of the sintered body is 0.3 to 3 μm. Further, it is preferable that the porosity of the rare earth cold accumulating material particle is 20 to 45 vol. %, and a maximum pore size of the rare earth cold accumulating material particle is 4 μm or less. Due to this structure, there can be provided a rare earth cold accumulating material having a high refrigerating capacity and a high strength.

With an aim to provide a method for producing an oxide particle with controlled color characteristics and also provide an oxide particle with controlled color characteristics, the present invention provides a method for producing an oxide particle, wherein the color characteristics of the oxide particle are controlled by controlling a ratio of an M-OH bond between an element (M) and a hydroxide group (OH) or an M-OH bond/M-O bond ratio, where the element (M) is one element or plural different elements other than oxygen or hydrogen included in the oxide particle selected from metal oxide particles and semi-metal oxide particles. According to the present invention, by controlling the M-OH bond or the M-OH bond/M-O bond ratio of the metal oxide particle or the semi-metal oxide particle, the oxide particle with controlled color characteristics of any of reflectance, transmittance, molar absorption coefficient, hue, and saturation can be provided.

With an aim to provide a method for producing an oxide particle with controlled color characteristics and also provide an oxide particle with controlled color characteristics, the present invention provides a method for producing an oxide particle, wherein the color characteristics of the oxide particle are controlled by controlling a ratio of an M-OH bond between an element (M) and a hydroxide group (OH) or an M-OH bond/M-O bond ratio, where the element (M) is one element or plural different elements other than oxygen or hydrogen included in the oxide particle selected from metal oxide particles and semi-metal oxide particles. According to the present invention, by controlling the M-OH bond or the M-OH bond/M-O bond ratio of the metal oxide particle or the semi-metal oxide particle, the oxide particle with controlled color characteristics of any of reflectance, transmittance, molar absorption coefficient, hue, and saturation can be provided.

The disclosure is directed to a spherical particle comprising lanthanide hydroxide, a method of preparing the particle, the particle for use in medical applications, a suspension, a composition, a method of obtaining a scanning image, and the particle for use in the treatment of a subject.

The disclosure is directed to a spherical particle comprising lanthanide hydroxide, a method of preparing the particle, the particle for use in medical applications, a suspension, a composition, a method of obtaining a scanning image, and the particle for use in the treatment of a subject.

The invention includes apparatus and methods for instantiating rare earth metals in a nanoporous carbon powder.