1428results about "Alkali-metal aluminates/aluminium-oxide/aluminium-hydroxide preparation" patented technology

A process for extracting aluminum oxide from powdered coal ash includes such steps as grinding, calcining, mixing with H2SO4 solution, heating while reaction for extracting aluminum oxide, boiling in water, concentrating, cooling while educing out aluminum sulfate crystals, heating for dewatering, heating for decomposing to obtain gamma-Al2O3, and further preparing metallurgy-class aluminum oxide.

Micelle-templated superficially porous particles having a solid core and an outer porous shell with ordered pore structures and a narrow particle size distribution, such as about ±5% (one sigma), and a high specific surface area of about 5 to about 1000 m²/g.

The invention belongs to the technical field of comprehensive utilization of waste resources from the aluminum industry and specifically discloses a comprehensive utilization method of aluminum ash. According to the comprehensive utilization method of aluminum ash, metallic aluminium is extracted from aluminum ash through an ore grinding method; the aluminum ash obtained after aluminium extraction undergoes catalytic deamination; the aluminum ash obtained after deamination is mixed with alkali and granulation forming is then carried out; and the granulation product is sintered and the sintered product is finally dissolved out. By the above method, useful components in the aluminum ash can be recovered to the maximum; ammonia gas which has been ignored for a long time is effectively recovered; components such as aluminium oxide, villiaumite and the like are recovered and utilized to the maximum; pollution of aluminum ash processing to the environment is avoided; atmospheric dust pollution is avoided; atmospheric pollution is also avoided due to ammonia gas recovery; pollution of aluminum ash stacking to underground water and soil is avoided due to extraction and recovery of fluoride salt; and environmental safety during the treating process is guaranteed.

The claimed invention is a method for separating Bayer process red mud from a Bayer process liquor which comprises adding to a Bayer process liquor containing red mud an effective amount of a water soluble synthetic flocculant, dextran and starch combination. The flocculant is added anywhere in the slurry containing the red mud suspended in Bayer process liquor, or in a liquor slurry containing bauxite prior to or during digestion. Once the flocculant combination is added, it is mixed sequentially with the Bayer process liquor and the red mud contained in the Bayer process liquor is removed by sedimentation, centrifugation or filtration.

The invention discloses a method to produce highly pure Alumina powder. The steps are as follows: deploying Aluminium hydroxide which is produced in the process of manufacturing alumina using sintering process to be solution, disposing of impurity, adding seed crystal to prepare highly pure aluminium hydroxide; removing Na in the solution, getting highly pure bodhmite after hydrothermal synthesis; and after washing and baking, highly pure Alumina can be obtained. The cost is about 15 thousand per ton, which is far less than current market price, 40-60 thousand per ton. It can put into production in a large scale and it is easy to reach 1-5 thousand ton per year. With a low cost, no pollution and high purity (over 99.99 percent), the production is widely used in rare earth fluorescence materials, high voltage Na lamp and other relative special Alumina fine ceramics field.

The present invention relates to Fe-Al spinel and its preparation process. The technological scheme of the present invention is the Fe-Al spinel preparing process including the steps of: mixing Al containing compound and Fe containing compound in the molar Al/Fe ratio of 2 and adhesive in 1-6 wt% for 5-180 min; forming and drying at 90-120 deg.c for 20-30 hr; heating in carbon atmosphere and temperature raising speed of 0.5-10 deg.c/min at 1100-1700 deg.c for 5-600 min; and naturally cooling. The present invention has the advantages of simple technological process, low reaction temperature and cheap material. Under the sintering temperature, all the Al and Fe components are converted into FeAl2O4, and the sintered product has apparent porosity lower than 5 %.

The invention relates to a preparative method of pseudo-boehmite, belonging to the field of the preparative technology of alumina exclusive of metallurgical usage. The method comprises the steps as follows: sodium metaaluminate solution is carbonated into mucus, aging, separating, washing and drying. The invention is characterized in that after the sodium metaaluminate solution becomes mucus, pulp-liquid separation is carried out primarily; filter cake is added; heating and aging are performed after water washing and mixed pulping. The invention has the advantages of low washing water consumption, low production cost, easy control of product quality and good practicality.

The invention relates to a method for producing sponge iron co-production sodium aluminate solution by using Bayer process red mud. The method comprises the following steps of: washing the Bayer process red mud, and then drying and crushing the washed Bayer process red mud; mixing the crushed Bayer process red mud with a first type auxiliary agent, a second type auxiliary agent and a catalytic auxiliary agent so as to prepare a mixed green stock; sintering the mixed green stock to prepare a high-temperature sintered clinker; performing dry magnetic separation on the high-temperature sintered clinker, and then grinding the high-temperature sintered clinker to obtain a magnetic material and a first type non-magnetic material; performing dissolution reaction on the magnetic material and a carbon content mother liquor which is obtained by decomposing the sodium aluminate solution in an alumina refinery to obtain the sodium aluminate solution and a ferruginous filter cake; and performing wet magnetic separation on the ferruginous filter cake to obtain a magnetic sponge iron and a second type non-magnetic material. The method for producing the sponge iron co-production sodium aluminate solution by using the Bayer process red mud uses waste materials generated in an alumina production process, changes the waste materials into valuable, and reduces pollutions to the environment because of the deposition of the red mud.

A process for preparing nanofibres of aluminium oxide includes such steps as mixing surfactant with aluminium hydroxide, hydrothermal treaitng at 293-573 deg.K for 5-80 hr, and firing at 473-1573 deg.K for 1-40 hr. Its product has high specific surface area (more than 350 sq.m/g).

Provided are a proton-exchange membrane of which the ionic conductivity is high and the methanol crossover is low, and a fuel cell of high power that comprises the proton-exchange membrane. The proton-exchange membrane has a structure of mesogen-containing organic molecular chains and a proton-donating group-containing group covalent-bonding to a silicon-oxygen three-dimensional crosslinked matrix, in which at least a part of the organic molecular chains are oriented to form an aggregate thereof; and the fuel cell comprises the membrane.

The invention provides a method for safely and efficiently producing sand-like alumina from aluminum ash. The method comprises the steps as follows: 1) aluminum ash is added to a sodium aluminate to react with the sodium aluminate solution, then solid-liquid separation is performed, a first-section digestion liquid and aluminum ash residues are obtained, and hydrogen and ammonia gas are comprehensively utilized; 2) alkali and an additive are added to the aluminum ash residues, raw slurry is obtained, and thus chlorine and fluorine elements are prevented from entering tail gas; 3) the raw slurry is sintered and clinker is obtained; 4) the clinker is added to an adjustment liquid for digestion, and second-section digestion slurry is obtained; 5) the first-section digestion liquid and the second-section digestion slurry are mixed in a Bayer process digestion slurry dilution system for production of the sand-like alumina by the Bayer process system. Nitrogen, fluorine, chlorine, hydrogen and other harmful elements in the aluminum ash are disposed safely, the concentration of organic matter in a Bayer process solution is decreased, and aluminum components are recovered efficiently and economically; for the aluminum ash, the method has the characteristics of safety, high efficiency, low cost and the like; for the Bayer process system, the yield is increased, the solution is purified, and the production efficiency is significantly improved.

A method of preparing pseudoboehmite is disclosed. The method includes preparing aluminium hydroxide precipitate, ageing, washing and drying. The preparation of the aluminium hydroxide precipitate adopts a reactor, wherein the reactor comprises a reactor cylinder and is provided with a stirrer inside, the bottom of the reactor cylinder is provided with two feeding ports, two material circulating pipelines are disposed outside the reactor cylinder, each of the material circulating pipelines is provided with at least one outlet, circulating material outlets are in the upper part of the reactor cylinder, inlets of the two material circulating pipelines are respectively connected to the two feeding ports through pipelines, and the upper part of the reactor cylinder is provided with an overflow port that is higher than the circulating material outlets. Pseudoboehmite particles prepared by the method are uniform in particle size, so that prepared aluminum oxide is large in pore volume, large in pore diameter and centralized in pore distribution, and the prepared aluminum oxide is uniform and constant in properties.

The invention provides methods and compositions for improving the production of alumina hydrate. The invention involves adding one or more polysaccharides to liquor or slurry in the fluid circuit of the production process. The one or more polysaccharides can be a cross-linked polysaccharide (such as cross-linked dextran or cross-linked dihydroxypropyl cellulose). The various polysaccharides can impart a number of advantages including at least some of: greater flocculation effectiveness, increasing the maximum effective dosage, faster settling rate. The production process can be a Bayer process.

Sodium is reacted with water to form hydrogen, sodium hydroxide and heat, and the sodium hydroxide is reacted with aluminum to produce hydrogen and sodium aluminate, while the violent nature of the reactions is modulated by employing the exothermic heat of the reactions to convert solid sodium to liquid sodium and to convert liquid water to steam. The pressurized hydrogen generated is used to drive one or more power generators which utilize pressure to generate power. The reactions take place in a reaction chamber in which a water reservoir is disposed in open communication with a main reaction chamber.

The invention discloses a method for harmlessly treating aluminum ash and preparing sandy alumina. The method disclosed by the invention mainly comprises the following main steps of remelting, alkaline washing, drying and sintering, dissolving out, filtrating and purifying, carbon component decomposition, and roasting, and is specifically implemented by taking aluminum ash produced in the processes of aluminum electrolytic smelting and coarse aluminum refining as a raw material through the process post-treatment steps of recovering metallic aluminium, carrying out alkaline wash for removing impurities, sintering sodium carbonate, dissolving out sintered clinker, carrying out deep impurities removal on a sodium aluminate solution, separating and washing carbon components and aluminum hydroxide, roasting aluminum hydroxide, evaporating carbon component mother liquor, and the like, so that a sandy alumina product is obtained. Fluorine in aluminum ash, after being discharged in silicon fluoride form, is absorbed by using an aqueous solution. The method disclosed by the invention realizes the harmless treatment of aluminum ash, the method is simple in process and low in production cost, and the environmental pollution and the resource wastes caused by the aluminum ash are avoided.

In the invention, meta-aluminate and soluble glass are used as raw materials to preparate aluminum oxide with high-temp. resistant and high specific surface by techonlogy that using sol-gel process to prepare aluminium oxide humidity gel and using supercritical fluid drying method to prepare aluminum oxide xerogel. The aluminum oxide contains silicon oxide (wt% is 0.1-10), the aluminum oxide xerogel is processed for 4h on 500 deg.c temp., its specific superficial area is more than 365 m2/g, then it is processed for 4h, its specific superfical area is more than 165 m2/g.

The invention relates to a method for preparing a nano material, which comprises the step of: preparing a nano material precursor and a nano material. The method for preparing the nano material precursor comprises the step of: placing reacting raw materials in a supergravity filed reactor for gas-liquid reaction or liquid-liquid reaction to obtain the nano material precursor. The method for preparing the nano material comprises the step of heating and roasting the nano material precursor with a microwave field to ensure that the nano material precursor generates decomposition or recrystallization to obtain the nano material. The method for preparing the nano material precursor also comprises the step of: in a process of accelerating and enhancing the mass transfer with the supergravity filed, enabling a metal salt water solution in the reactor to be uniformly mixed with a liquid precipitator or gas precipitator in a molecule size manner for chemical reaction to obtain the nano material precursor of carbonate materials or nano oxyhydrate materials or hydrous oxide materials of the metal, wherein the prepared nano material is used as a nano metal oxide. The method has the advantagesof scientific and reasonable structure, high quality of products, energy saving, no secondary pollution and the like.

A method to produce aluminum oxide with middle-low bauxite relates to a method to produce aluminum oxide with middle-low bauxite by the means of Bayer-method. The invention is characterized in that: during the Bayer-method process, digestion process is to add dealuminization slag instead of lime as additive in middle-low bauxite to do Bayer process digestion; after digestion and backward washing of red mud, the red mud is mixed with recycle alkaline liquor, the lime is added, the digestion reaction is done, the red mud is separated from the slurry and discharged outside, the solution part obtained oppositely washes with Bayer-method, is sent to Bayer-method system to supplement alkali after digesting the red mud, the lime is added partly and is reacted, then, dealuminization slag and recycle alkaline liquor that goes through Bayer-method red mud wet treatment are gotten and dealuminization slag calcium aluminate hydrate instead of lime is added into the Bayer process digestion. The method of the invention belongs to all wet treatment, has simple process, low energy consumption, low alkali consumption and high recovery rate of aluminum oxide and is suitable for treating Chinese bauxite that is mainly middle-low bauxite; besides, the resource utilization is high, the amount of discharged red mud is low and the red mud is easy to be utilized comprehensively.