93results about "Rare earth metal sulfides" patented technology

A new, cost effective process for the production of ultrafine particles which is based on mechanically activated chemical reaction of a metal compound with a suitable reagent. The process involves subjecting a mixture of a metal compound and a suitable reagent to mechanical activation to increase the chemical reactivity of the reactants and/or reaction kinetics such that a chemical reaction can occur which produces a solid nano-phase substance. Concomitantly, a by-product phase is also formed. This by-product phase is removed so that the solid nano-phase substance is left behind in the form of ultrafine particles. During mechanical activation a composite structure is formed which consists of an intimate mixture of nano-sized grains of the nano-phase substance and the reaction by-product phase. The step of removing the by-product phase, following mechanical activation, may involve subjecting the composite structure to a suitable solvent which dissolves the by-product phase, while not reacting with the solid nano-phase substance. The process according to the invention may be used to form ultrafine metal powders as well as ultrafine ceramic powders. Advantages of the process include a significant degree of control over the size and size distribution of the ultrafine particles, and over the nature of interfaces created between the solid nano-phase substance and the reaction by-product phase.

Crystalline scintillator materials comprising nano-scale particles of metal oxides, metal oxyhalides and metal oxysulfides are provided. The nano-scale particles are less than 100 nm in size. Methods are provided for preparing the particles. In one method, used to form oxyhalides and oxysulfides, metal salts are dissolved in water, and then precipitated out as fine particles using an aqueous base. After the particles are separated from the solution, they are annealed under a flow of a water saturated hydrogen anion gas, such as HCl or H₂S, to form the crystalline scintillator particles. The other methods take advantage of the characteristics of microemulsion solutions to control droplet size, and, thus, the particle size of the final nano-particles. For example, in one method, a first micro-emulsion containing metal salts if formed. The first micro-emulsion is mixed with an aqueous base in a second micro-emulsion to form the final nano-scale particles.

A process for the production of nanorods containing a rare earth metal is disclosed. The process comprises the steps of: (a) increasing the pH of an aqueous solution of the formula MX₃, where M is a trivalent rare earth metal cation and X is a monovalent anion so as to produce a reaction product containing X anions in solution and a precipitate in the form of trivalent rare earth hydroxide nanoparticles of the formula M(OH)₃, the nanoparticles having a hexagonal crystal structure; and, (b) ageing the nanoparticles of step (a) in the presence of the reaction product containing X anions in solution so as to cause rod-like anisotropic growth of the nanoparticles and form rare earth hydroxide nanorods.

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.

The present invention relates to a method for recovering rare earth metals from waste sulphate materials, such as waste gypsum, which is a known secondary resource of rare earth metals and widely present e.g. in areas, where industrial phosphate production takes place. The present invention combines sulphate reduction treatment, such as bioreduction with sulphate reducing bacteria, and magnetic separation, which is based on an exceptionally high magnetic susceptibility of rare earth compounds compared to e.g. calcium compounds in such reductively pretreated gypsum precipitate.

The invention discloses a process method of rare earth oxysulfide by using an alkali chloride. The method comprises the following steps: (1) weighing required materials RE2O2S (wherein RE is one of rare earth elements Y, La, Gd and Sm), Na2CO3, sublimed sulfur and alkali chloride AMCl (wherein AM is one of alkali metal elements Li, Na or K) according to a stoichiometric ratio and uniformly mixing the weighed materials; (2) putting the uniformly mixed materials into inner and outer crucibles, and filling high-temperature powder in the gap between the two crucibles and compacting, where each of the two crucibles has a cover; (3) raising the temperature of the crucibles with the mixed material to 1100-1250 DEG C in a gradient way, sintering for 3-5 hours and then cooling to room temperature along with a furnace; (4) washing the sintered product with hot water, stirring, and carrying out suction filtration; and (5) drying the washed product into a constant-temperature blowing drying box to obtain the rare earth oxysulfide. By taking RE2O3, Na2CO3, sublimed sulfur and alkali chloride AMCl as raw materials, the rare earth oxysulfide is prepared by using a sulfur melting method. The preparation method of the rare earth oxysulfide is simple and easy to operate and the rare earth oxysulfide can be used in the fields of light-emitting materials and photoabsorption materials and the like.

The invention relates to a preparation method of a rare earth sulfide and/or rare earth oxysulfide colouring agent. The preparation method comprises following steps: a rare earth compound, sulphur, analkali metal compound, an organic auxiliary agent, and a borate are taken as raw materials, and are subjected to drying; the dried raw materials are mixed fully, and are introduced into a die for pressing moulding so as to obtain a powder cake for calcining, and the rare earth sulfide and/or rare earth oxysulfide colouring agent is obtained at last. The product performance of the rare earth sulfide and/or rare earth oxysulfide colouring agent is stable; the yield is high; the lightness is high; the color degree is stable; the particle size is small; the homogeneity is high; the hardness and the stability of the powder cake are improved; transportation, moving, and storage are convenient; the hardness of the powder cake processed through calcining is higher, it is convenient to take the powder cake from a porcelain jar; automatic filling, automatic sampling, impurity removing, and crushing are convenient to realize, and the particle size of particles obtained through crushing is about0.5 to 5 micrometers.

The invention relates to a method for synthesizing high-stability gamma-Pr2S3 powder. By virtue of the method, high-purity gamma-Pr2S3 powder with a cubic structure within a temperature range from the room temperature to 1340 DEG C and stable thermodynamics performance at a relatively low preparation temperature and a relative short temperature maintenance time can be obtained. The problems that the vulcanizing temperature is high, the time is long, the cost is high, or the product stability is low, the purity is low, and carbon pollution and sulfur oxide impurities are easily produced in the prior art are solved. Gamma-phase Pr2S3 belongs to a stable phase at a temperature higher than 1340 DEG C, so that praseodymium sulfide powder prepared by virtue of the method can stably preserve a gamma-phase structure in a whole temperature range. Meanwhile, the method is simple in process, low in cost and applicable to the large-scale preparation of high-stability high-purity gamma-phase praseodymium sulfide, and has wide application prospects.

The invention discloses a preparation method of an aluminum oxide coated gamma-Ce2S3 red pigment. The preparation method comprises the following steps: firstly, preparing an aluminum hydroxide coatedCeO2 precursor through a liquid-phase method; then carrying out vulcanization atmosphere and inert atmosphere high-temperature vulcanization heat treatment to obtain the aluminum oxide coated gamma-Ce2S3 red pigment. Furthermore, the invention further discloses a product prepared by the preparation method. According to the preparation method disclosed by the invention, gamma-Ce2S3 is effectively stabilized through coating aluminum oxide, so that the high-temperature stability of the coated modified pigment is greatly improved and an application field of the pigment is extremely expanded; the preparation method disclosed by the invention has the advantages that a technology is simple, reaction is easy to control, and a preparation process and product performance are more stable and reliable, so that industrialized popularization and application is facilitated.

The invention discloses a zirconium silicate-coated low-valence ion co-doping gamma-Ce2S3 red pigment which is composed of low-valence ion co-doping gamma-Ce2S3 red pigment powder and a zirconium silicate transparent shell coating the surface of the low-valence ion co-doping gamma-Ce2S3 red pigment powder, wherein in the low-valence ion co-doping gamma-Ce2S3 red pigment powder, the ion valence ofthe doping ion M is 2, and at least two doping ions exist according to a molar ratio of 2(1-x):3x between Ce<3+> and M(total), where x is greater than 0 and less than or equal to 0.1. The invention also discloses a preparation method of the gamma-Ce2S3 red pigment. According to the zirconium silicate-coated low-valence ion co-doping gamma-Ce2S3 red pigment disclosed by the invention, the gamma-Ce2S3 crystal structure is stabilized internally through a way of low-valence ion co-doping while the gamma-Ce2S3 is coated externally with zirconium silicate which is stable at high temperature, therebyremarkably improving the high-temperature stability of the gamma-Ce2S3 red pigment and significantly expanding the application field of the gamma-Ce2S3 red pigment. The preparation method disclosed by the invention has the advantages that the technology is simple and easy to operate, the influence factors are easy to control, the production cost is low and the promotion and application are facilitated.

The invention discloses a preparation method of cerium oxysulfide porous nano-sheets. The preparation method includes the steps: (1) mixing thiourea group compounds and cerium salt solution, adding ethylene glycol amine into mixture of the thiourea group compounds and the cerium salt solution, and performing hydrothermal reaction and cooling; (2) filtering substances acquired after cooling of mixture in the step (1), cleaning and drying filter residues, performing hydrothermal reaction and cooling, and collecting samples to obtain the cerium oxysulfide porous nano-sheets. According to the method, cheap cerium salt, thiourea and the like serve as precursors, cerium oxysulfide is prepared by the aid of hydrothermal reaction and heat treatment, the prepared cerium oxysulfide is provided with pure-phase mono-crystal nano-sheets, the nano-sheets have mutually penetrated holes, so that the specific surface area of a cerium oxysulfide material is improved, and the preparation method is simple in reaction condition and device, simple, convenient, easy, economical and environmentally friendly and has great potential practical values.

The invention discloses a preparation method for preparing two-dimensional layered transition metal sulfide. The two-dimensional layered transition metal sulfide is mainly an MAX-phase ceramic powderraw material composed of the following elements. Wherein the M element is Ti, Nb, V, Y, Nb, Mo, Ta, W, Hf, Cr and Mn; wherein the element A is Al, Si, Ge, Sn, Ga and Sb; powder of max-phase ceramic ofwhich the X element is B, C, N and Si and powder of MAB-phase ceramic are used as raw materials; in the atmosphere containing H2S, H2Se and H2Te gas, the powder is heated for more than 5 hours withinthe temperature range of 500-1400 DEG C, and organ-shaped TMDCS powder can be obtained after the obtained powder is subjected to ball milling. According to the method, a CVD method and a mechanical stripping high-cost method for preparing the TMDCS are eliminated, an organ-shaped structure which cannot be obtained through the CVD method and the mechanical stripping method can be obtained, the cost is obviously reduced, and application and popularization of a two-dimensional TMDCS material are often facilitated.

The invention discloses a preparation method of a novel rare earth red pigment gamma-Ce2S3. The preparation method comprises the following steps: preparing modified CeO2 composite nano precursor powder and calcining and molding the red pigment gamma-Ce2S3. The preparation method of the modified CeO2 composite nano precursor powder comprises the following steps: preparing a CeCl3 solution and a Na2S solution, preparing a CeO2 precursor sample, preparing a CeO2 nano powder precursor and molding the modified CeO2 composite nano powder precursor. The calcining and forming process of the red pigment gamma-Ce2S3 comprises the following steps: calcining the modified composite nano-powder precursor and forming the red pigment gamma-Ce2S3. The red pigment gamma-Ce2S3 prepared by the preparation method disclosed by the invention has the advantages that the tinting strength, glossiness, purity and color intensity are obviously improved, meanwhile, the adhesive force is also obviously enhanced, the experiment result is stable through repeated experiments, and the preparation method is simple and reliable.