459results about "Aluminates/aluminium-oxide/aluminium-hydroxide purification" patented technology

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 invention discloses a red mud dealkalization method at normal pressure by Bayer process, wherein the dealkalizing step consists of, washing and filtering the red mud, charging lime cream into the red mud filter cake, mixing for dealkalizing reaction, subjecting the reaction slip to washing, filtering, drying and discharging.

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.

The invention belongs to the technical field of recycling of electrolytic aluminum industrial wastes and specifically discloses a processing method for an aluminum electrolysis waste cathode carbon block. The processing method comprises the following steps: breaking the waste cathode carbon block and then adding water for ball-milling, performing decyanation treatment, leaching with hot water, leaching with concentrated sulfuric acid, washing and performing flotation, thereby acquiring a first-level carbon powder product and a second-level carbon powder product; reacting a primary acid leaching solution with a sodium hydroxide solution and filtering, thereby acquiring solid aluminum hydroxide; mixing the reaction filtrate with lime and filtering, thereby acquiring calcium sulfate; using water for absorbing the mixed gas formed by the primary washing gas and the acid leaching gas, thereby acquiring a hydrofluoric acid solution; mixing the prepared hydrofluoric acid solution with a ball-milling separating liquor and a hot water leaching separating liquor; adding aluminum hydroxide into the mixed liquor; filtering and separating the reactants; filtering, thereby acquiring the liquid phase of reusable water and the solid phase of fluorine-containing aluminum hydroxide; and roasting, thereby acquiring a fluorine-containing aluminum hydroxide product. According to the method providedby the invention, the harmless comprehensive recycling of the aluminum electrolysis waste cathode carbon block is realized.

This invention relates to treated geothermal brine compositions containing reduced concentrations of lithium, iron and silica compared to the untreated brines. Exemplary compositions contain concentration of lithium ranges from 0 to 200 mg/kg, concentration of silica ranges from 0 to 30 mg/kg, concentration of iron ranges from 0 to 300 mg/kg. Exemplary compositions also contain reduced concentrations of elements like arsenic, barium, and lead.

A floatation process for bauxite to remove S and Si includes such steps as grinding the crude bauxite, adding the yellow catching agent B, reverse floatation for removing S, grinding, adding the match of saponified fatty acid and naphthenic acid, and forward floatation. The resultant bauxite concentrate can be used to prepare aluminum oxide by Bayer method.

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.

In the mining process, linear, branched, hyperbranched or dendrimeric polyols or mixtures thereof are employed as process stabilization aids for aqueous solutions and, or suspensions of metal salts. A specific application area of the polyols is the stabilization of bauxite liquor in the Bayer process of producing alumina from bauxite.

This invention discloses a method for producing aluminium oxide by using aluminium-containg are with low aluminium/silicon ratio. The method comprises procedures of: (1), atomizing raw material ore; (2), dressing by magnetic separation; (3), acid treatment; (4), filtering and separation; (5), heating for dehydration decomposition; (6), recovering sulfur trioxide. After that, produced is the inventive product aluminium sesquioxide with high pureness upto 99.5%, meeting the standard of Non-Ferrous Metals Industries SY/T274-1998. The advantages of this invention are; full reutilization of materials, simple process, simple equipment, no discharge of wastes of solid, liquid and gas, no secondary pollution.

The invention relates to a method for reducing the content of sodium in aluminum hydroxide, in particular to a method for preparing low-sodium aluminum hydroxide (Na2O is less than 0.1 percent) serving as a fire retardant or a raw material for calcining low-sodium aluminum oxide. The method is characterized by comprising the following steps of: after homogenizing the aluminum hydroxide by using pure water, performing hydro-thermal treatment, and filtering, washing and drying to obtain low-sodium aluminum hydroxide powder. In the method, the aluminum hydroxide prepared by a Bayer process or a sintering process is subjected to the hydro-thermal treatment, so that adherent alkali and lattice alkali in the aluminum hydroxide are dissolved in the water, and the low-sodium aluminum hydroxide powder is obtained by processes of solid-liquid separation, washing, drying and the like, wherein the powder can be used as the fire retardant or the raw material for calcining the low-sodium aluminum oxide. The method has the advantages that a process is simple, industrialization is easy to realize and the like, so the using performance of the aluminum hydroxide fire retardant can be improved effectively, and the low-sodium aluminum hydroxide can be used as the raw material for calcining low-sodium alpha-aluminum oxide.

The invention discloses a method for activating and regenerating waste industrial activated aluminum oxide. The method comprises pretreatment, cleaning liquid impregnation treatment and regeneration treatment; adopted cleaning liquid is selected from at least one of acid liquor and alkali liquor and surfactant solution; the regeneration treatment comprises regenerated liquid impregnation and calcination treatment, and adopted regenerated liquid is selected from aluminum-contained solution; the calcination treatment is performed under air atmosphere, and air inlet amount is 300 to 800 m<3>/(h.t). According to the method for activating and regenerating the waste industrial activated aluminum oxide provided by the invention, an original pore structure channel is dredged through a physical and chemical method, and a new pore structure is regenerated on the basis of the existing pore structure to obtain activated aluminum oxide with high specific surface area and high pore volume.

The invention provides a method of inhibiting the accumulation of DSP scale in the liquor circuit of Bayer process equipment. The method includes pre-treating surfaces of the process equipment with one or more particular silane based small molecules. These scale inhibitors reduce DSP scale formation and thereby increase fluid throughput, increase the amount of time Bayer process equipment can be operational and reduce the need for expensive and dangerous acid washes of Bayer process equipment. As a result, the invention provides a significant reduction in the total cost of operating a Bayer process.

The invention discloses a method for removing sodium in a preparation of high-purity alumina. The method comprises the steps of purifying, secondary purifying, washing, drying, secondary washing and drying again. The method specifically comprises the following steps of: grinding aluminium hydroxide with high sodium content to be less than or equal to 500mu m, stirring and washing for 2-3 times in thermostatic water bath with temperature being 50-55 DEG C by utilizing a sodium removing agent I to obtain pure aluminium hydroxide; washing the purified pure aluminium hydroxide with water till pH value is 7.0-7.5, drying and dehydrating; adding a sodium removing agent II to the washed and dried aluminium hydroxide, and stirring and washing for 2-3 times in the thermostatic water bath with temperature being 30-50 DEG C; and washing the aluminium hydroxide which is purified for the second time by utilizing pure water with temperature being 30-50 DEG C, drying, dehydrating and transforming the washed aluminium hydroxide to fluffy ultralow sodium aluminium hydroxide. The method has the advantages of convenience, conciseness, no pollution and good sodium-removing effect.

A method is disclosed of synthesizing an aluminophosphate or metalloaluminophosphate molecular sieve comprising an AEI structure type material, in which the rate of heating to the crystallization temperature is controlled, either alone or in combination with the H₂O:A1₂O₃ molar ratio of the synthesis mixture, so as to enhance the yield of the desired molecular sieve product.

The invention discloses a method for reducing sodium oxide in aluminum oxide by using carbon dioxide. The method comprises the following steps of: pre-baking aluminum hydroxide and adding a baked product into water to prepare baked product aqueous solution for later use; introducing CO2 gas into the baked product aqueous solution and fully stirring; adding a small number of sodium removing agents into the baked product aqueous solution into which the CO2 gas is introduced; performing liquid-solid separation; drying to obtain a solid; calcining the solid at a high temperature; and naturally cooling to obtain low-sodium aluminum oxide. By the method, the cost for manufacturing the high-temperature low-sodium aluminum oxide can be reduced, the variation in product performance caused by the sodium removing agent can be reduced, and a new approach is discovered for utilization of the carbon dioxide.

The invention discloses a method for selectively leaching nitric acid from lithium element in aluminum electrolyte, and relates to the technical field of aluminum electrolyte extraction recycling. Themethod comprises the following steps that 1, aluminum electrolyte containing the lithium element is smashed and screened; 2, nitric acid and water are mixed, the pH value of the acid solution is adjusted to be smaller than 4, and the electric potential is adjusted to be between 0.015V and 0.8V; 3, the aluminum electrolyte is added into the acid solution, stirred, heated and leached, the reactiontemperature is 20-85 DEG C, the adding amount of aluminum electrolyte is controlled according to the concentration and acidity of fluorinion in the solution, the acidity pH value is smaller than 4, and the fluorinion concentration is larger than 1g/L; 4, the mixed solution is filtered and washed to obtain filtrate and filter matter; and 5, the filtrate is used for extracting the lithium element, the filter matter is washed, dried and returned to an aluminum electrolyte plant to produce aluminum electrolyte and/or retuned to a leaching process. Lithium salt is selectively leached, high-additional-value lithium salt is recycled, industrial aluminum electrolyte high in purity and applicable to aluminum electrolyte production is obtained, and the energy consumption and extraction cost for aluminum electrolyte production are low.

The invention provides a method for preparing high-purity ultrafine Al2O3 powder. The method comprises the following steps of: uniformly mixing metal aluminum, water and a catalyst in a certain ratio, performing microwave heating, cooling to room temperature, obtaining an aluminum hydroxide precipitate, and discharging hydrogen; and washing the aluminum hydroxide precipitate through high-purity water, and performing suction filtration, dehydration and calcination to obtain 4 to 5N high-purity ultrafine Al2O3 powder. In the whole preparation process, a flow is short, a process is simple, the reaction speed is high, energy consumption and cost are low, the purity is easy to control, toxic and harmful gases and liquid are not generated, high-efficiency large-scale production can be performed, and obvious economic benefits and social benefits can be produced.

A method for recovering alkali and aluminum during treatment of Bayer red mud using a calcification-carbonation method, including steps of mixing the Bayer red mud with calcium aluminate or with calcium aluminate and lime, performing calcification dealkalization conversion in a high-concentration alkaline liquor, and carbonizing the calcified residues produced during dealkalization to obtain carbonized residues; and then performing low-temperature aluminum dissolution, aluminum precipitation and the like to obtain calcium aluminate products, which is returned to the calcification dealkalization conversion of the red mud for recycling. Part of an alkali-containing and aluminum-containing liquid phase after calcification dealkalization conversion can be used as supplementary alkali in the Bayer production course for recycling. The method is energy-saving and environmentally-friendly, and allows recovering alkali and aluminum from the red mud and harmless treatment of the Bayer red mud.

The invention provides a method of inhibiting the accumulation of DSP scale in the liquor circuit of Bayer process equipment. The method includes adding one or more particular silane based small molecules to the liquor fluid circuit. These scale inhibitors reduce DSP scale formation and thereby increase fluid throughput, increase the amount of time Bayer process equipment can be operational and reduce the need for expensive and dangerous acid washes of Bayer process equipment. As a result, the invention provides a significant reduction in the total cost of operating a Bayer process.

The invention discloses a production method of a 5N high-purity aluminum oxide polycrystal material, which is characterized by comprising the following steps: adding a 5N high-purity aluminum oxide powder material into a cold crucible defined by a copper tube coated with a high-temperature-resistant coating, using a 5N high-purity metal aluminum sheet as an igniter, and adopting a high-frequency cold crucible technology to produce the 5N high-purity aluminum oxide polycrystal material product, wherein the appearance and shape of the product is a white columnar and acicular particle, the density is 3.5-3.9 g/cm<3>, the bulk density is 2.2-2.6 g/cm<3>, and the purity is greater than 5N. The production method disclosed by the invention is simple and easy to implement, and has the advantages of cost saving, energy saving, environment friendliness and the like.