492results about "Aluminium hydroxide preparation" patented technology

Disclosed is an amplifying optical fiber having a central core and an optical cladding surrounding the central core. The central core is based on a silica matrix that includes nanoparticles, which are composed of a matrix material that includes doping ions of at least one rare earth element. The amplifying optical fiber can be employed, for example, in an optical amplifier and an optical laser.

The invention discloses a preparation method for aluminum oxide by a direct forming method. The method is characterized in that the aluminum oxide is directly formed by a wet filter cake, wherein pore volume is 0.3-0.8ml/g; a specific surface area is 150-300 m<2>/g; and crushing strength is 30-120 N/particle; the preparation process comprises the steps: a) meta-aluminate containing aluminum or a strong acid salt compound is neutralized with a precipitator solution at a temperature of 30-80 DEG C and pH of 6-9; accessory ingredient is added in a neutralizing process; mixture is aged for at least 10min after neutralizing; b) prepared aluminium hydroxide gel is washed by de-ionized water for 4-10 times; dosage of the de-ionized water for each time is 10-40 times of mass of a dried substrate of prepared aluminium hydroxide; a hydrated alumina filter cake is obtained after washing and filtering; content of the aluminium hydroxide in the filter cake is controlled to be 5-50%; and c) the accessory ingredient is added into one or various liquid in the step a) and step b); the filter cake after washing is formed by a normal forming method; and the formed filter cake is dried at a temperature of 80-120 DEG C and calcined at a temperature of 450-1000 DEG C to obtain a finished product of the aluminum oxide.

The invention provides a method for preparing aluminum oxide and other products from aluminiferous materials such as bauxite, high iron bauxite, alunite, kaoline, alumina, fly ash, coal gangue, aluminum ash, nepheline, clay and the like. The method comprises the following steps: (1) crushing, grinding and mixing the aluminiferous materials with ammonium sulfate and then roasting; (2) dissolving the roasted product (clinker aggregate) in water, and filtering to obtain aluminum ammonium sulfate solution and filter residues; (3) carrying out deferrization, aluminum deposition or recrystallization on the aluminium ammonum sulfate solution with ammonia to prepare aluminum oxide, and meanwhile, recycling the ammonium sulfate; (4) preparing silicon dioxide from the filter residues, and taking the remaining residues containing ferrum as the raw material for ironmaking. The method is suitable for treating various aluminiferous materials, has the advantages of simple technical process, simple equipment, no emission of solid, liquid and gas wastes, and no secondary pollution, and realizes the high-added-value green complex utilization of the aluminiferous materials such as bauxite, high ironbauxite, alunite, kaoline, alumina, fly ash, coal gangue, aluminum ash, nepheline, clay and the like.

Materials and associated processes for making the materials. For example the material may include alpha alumina crystalline whiskers. The process may include conducting the process as hydrothermal, and producing the whiskers to have a length to diameter aspect ratio of at least two.

The invention relates to potassium feldspar decomposition and comprehensive utilization technology and in particular relates to a process for decomposing potassium feldspar by adopting a low-temperature semidry method for comprehensive utilization. The process comprises the steps of fully mixing potassium feldspar, fluorite and sulfuric acid, then adding the mixture to a converter reactor to react at 180-250 DEG C, separating SiF4 and HF generated through a reaction from a system under the condition of negative pressure, carrying out absorption with ethanol and water solution to prepare white carbon black, recovering fluorine resources in the process from the solution in the forms of ammonium fluoride and other aids by adopting the method of adding ammonia water and applying the recovered fluorine sources to decomposition of potassium feldspar and carrying out a series of processes such as extraction on the solids after a reaction to obtain calcium sulfate whisker, potassium fluosilicate, aluminium hydroxide and ferric sulfate products. Compared with the method for decomposing potassium feldspar by a high temperature method, the process has the advantages that the reaction conditions are mild and the requirements for equipment are lower; the white carbon black is directly prepared through gas hydrolysis, thus avoiding the tedious course from solid phase separation; and the fluorine resources introduced to the decomposition course are recycled by adopting the mode of ammonium fluoride, thus avoiding waste of the fluorine resources.

A process for preparing spherical alumina by oil-ammonia column includes dripping the alumina sol in the oil-ammonia column composed of upper oil phase and lower electrolyte solution phase to generate spherical gel particles, ageing in electrolyte solution for 0.5-10 hr, drying and calcining. Its advantage is high purity.

A mesoporous oxide composition includes, other than oxygen, a major amount of aluminum and lesser amounts of phosphorus and at least one rare earth element. The compositions have high surface area and excellent thermal and hydrothermal stability, with a relatively narrow pore size distribution in the mesoporous range. These compositions may be prepared by a hydrothermal co-precipitation method using an organic templating agent. These mesoporous oxide compositions may be used as catalysts or as supports for catalysts, for example, in a fluid catalytic cracking process.

The invention relates to a manufacturing method for ordered medium aperture alumina that includes the following steps: adding surface activator into inorganic aluminum salt as template agent, making precipitant solution, adding inorganic aluminum salt solution into hypergravity reactor, adding precipitant, when the reacting solution reaching a certain pH value, the precursor sol would be gained; taking aging, filtering, washing, and drying to the precursor sol to gain precursor powder. The powder could be made into ordered medium aperture alumina after taking sintering. The invention has the advantages of simple technology, safe to operate, low cost, etc. The specific surface of the product reaches 250-300m2/g, and the shape has certain orderliness. It has crucial application value in adsorption and catalyzing process.

The present invention relates to a process for the preparation of a plane-parallel structure (a platelet-shaped body, or flake), comprising at least one dielectric layer consisting of oxides of one or more metal selected from groups 3 to 15 of the periodic table, which method comprises: (a) optionally applying a layer of release material on a substrate, (b) applying a composition comprising one or more precursors of one or more desired metal oxides to said release layer, or directly to a substrate with no layer of release material, (c) subjecting the one or more precursors of one or more desired metal oxides to microwave radiation to form a metal oxide layer on the substrate or on the layer of release material; and (d) separating the resulting metal oxide layer from the substrate as plane-parallel structures.

The invention provides a method for producing ceramic nanoparticles, which comprises hydrolyzing a ceramic material in a thin film fluid formed between processing surfaces arranged to be opposite to each other so as to be able to approach to and separate from each other, at least one of which rotates relative to the other.

The present invention relates to the preparation process of active gamma-Al2O3. The mixed water solution of materials including aluminum chloride, ammonia water, pore expander ammonium oxalate or ammonium citrate, etc. is heated and concentrated to produce aluminum hydroxide precipitate; the precipitate is dried and heated to obtain solid powder and to decompose its NH4Cl, which is recovered from hot gas flow through cooling and crystallization; and the solid powder is roasted at 400-800 deg.c for 3-6 hr to convert into gamma-Al2O3. The present invention produces aluminum hydroxide through evaporation and concentration, rather than neutralization, and aluminium hydroxide is precipitated and separated in a stable and balanced solid-liquid state, and this is favorable to producing aluminium hydroxide grains with homogeneous size.

A process for preparing alumine powder with high sinter activity includes reaction of Al-contained inorganic salt chosen from aluminium nitrate, aluminium chloride and aluminium ammonium sulfate on ammonium bicarbonate at 5-50 deg.C to generate NH4Al(OH)2CO3, depositing and ageing for 2-24 hrs, washing with deionized water, baking at 50-150 deg.C and sintering at 1100-1200 deg.C to obtain alpha-Al2O3 particles less than 400 nm.

There are provided processes for extracting aluminum ions from aluminous ores. Such processes can be used with various types of aluminous ores such as aluminous ores comprising various types of metals such as Fe, K, Mg, Na, Ca, Mn, Ba, Zn, Li, Sr, V, Ni, Cr, Pb, Cu, Co, Sb, As, B, Sn, Be, Mo, or mixtures thereof.

The invention discloses a preparing method of excellent dispersing high-pure ultra-fine alpha-Al2O3, which comprises the following steps: adopting analytic pure aluminium-alcohol salt hydrating reaction; balling; drying; sintering; adding one carboxyl acid or surface activator in the dehydrating course; adding alpha-Al2O3 seed and additive ammonium salt in the balling course.

A method for producing α-alumina powder is described. The method comprises the steps of removing water from a compound containing the following (1), (2), (3) and (4), and calcining the results: (1) α-alumina precursor, (2) seed crystal, (3) water, (4) nitrate ion in an amount of from 2.8 to 3.3 mol per mol of aluminum (Al) contained in the α-alumina precursor and the seed crystal.

A method for the production of inorganic aluminum substances and amorphous silica from aluminum oxide containing ores, comprising: (a) leaching of said ores with fluorosilicic acid to obtain aluminum fluosilicate solution; (b) filtering said leached solution from insoluble materials; and (c) washing said insoluble materials.

The present invention relates to flaky alpha-alumina crystals with large aspect ratio and its preparation method, and particularly to flaky alpha-alumina crystals comprising aluminum oxide, zinc oxide and tin oxide, which are prepared by obtaining a mixed gel which are prepared by obtaining a mixed gel by means of hydrolysis of an aqueous aluminum precursor solution comprising aqueous flux, aqueous zinc precursor solution and tin precursor aqueous solution, followed by aging, drying and crystallization processes. The crystals herein have an average particle thickness of 0.5 um or less, an average particle diameter of 30 μm or higher and an aspect ratio of 100 or higher, thus being useful as a substrate of high quality pearlescent pigments, an abrasive, ceramic material and a filling material.

The invention relates to a method of manufacturing a product having a sub-micron primary particle such as metal oxide, metal oxidhydroxide or metal hydroxide product, said method comprising the steps of: introducing a solid reactor filling material in a reactor, introducing a metal-containing precursor in said reactor, introducing a co-solvent into the said reactor, introducing a supercritical solvent in the said reactor. By these steps a contact between the metal-containing precursor and the co-solvent is established, thus resulting in the formation of said product in the proximity of the said solid reactor filling material. The present invention offers the astonishing possibility of producing anatase phase of TiO₂ at temperatures as low as between 50° C. and 100° C. and at concurrent pressures of 100-200 bar. The invention also relates to a product such as anatase TiO₂ produced by the method and also relates to an apparatus utilising the method.