Showing papers on "Aluminium hydroxide published in 2012"

Formation of Crystalline Zn-Al Layered Double Hydroxide Precipitates on γ-Alumina: The Role of Mineral Dissolution

Abstract: To better understand the sequestration of toxic metals such as nickel (Ni), zinc (Zn), and cobalt (Co) as layered double hydroxide (LDH) phases in soils, we systematically examined the presence of Al and the role of mineral dissolution during Zn sorption/precipitation on γ-Al2O3 (γ-alumina) at pH 7.5 using extended X-ray absorption fine structure spectroscopy (EXAFS), high-resolution transmission electron microscopy (HR-TEM), synchrotron-radiation powder X-ray diffraction (SR-XRD), and 27 Al solid-state NMR. The EXAFS analysis indicates the formation of Zn−Al LDH precipitates at Zn concentration ≥0.4 mM, and both HR-TEM and SR-XRD reveal that these precipitates are crystalline. These precipitates yield a small shoulder at δAl‑27 = +12.5 ppm in the 27 Al solid-state NMR spectra, consistent with the mixed octahedral Al/Zn chemical environment in typical Zn−Al LDHs. The NMR analysis provides direct evidence for the existence of Al in the precipitates and the migration from the dissolution of γ-alumina substrate. To further address this issue, we compared the Zn sorption mechanism on a series of Al (hydr)oxides with similar chemical composition but differing dissolubility using EXAFS and TEM. These results suggest that, under the same experimental conditions, Zn−Al LDH precipitates formed on γ-alumina and corundum but not on less soluble minerals such as bayerite, boehmite, and gibbsite, which point outs that substrate mineral surface dissolution plays an important role in the formation of Zn−Al LDH precipitates.

Suzuki-Miyaura cross-couplings of arenediazonium tetrafluoroborate salts with arylboronic acids catalyzed by aluminium hydroxide-supported palladium nanoparticles.

Abstract: Suzuki-Miyaura cross-couplings of arenediazonium salts with arylboronic acids catalyzed by highly active aluminium hydroxide-supported palladium nanoparticles catalyst have been investigated for the first time. The reactions are performed at 25 °C in MeOH without any base and ligand to afford biaryls in good to excellent yields under non-anhydrous and non-degassed conditions.

A Novel Preparation Method of Ni–Sn Alloy Catalysts Supported on Aluminium Hydroxide: Application to Chemoselective Hydrogenation of Unsaturated Carbonyl Compounds

Abstract: A novel method was applied for the preparation of NiSn alloy catalysts that were utilized for chemoselective hydrogenation of unsaturated carbonyl compounds, producing unsaturated alcohols almost exclusively. The formation of the NiSn alloy may have played a key role in the enhancement of the chemoselectivity

Radiation cross-linked low-smoke halogen-free red phosphorus-free flame retardant material and its application

Abstract: The invention discloses a radiation cross-linked low-smoke halogen-free red phosphorus-free flame retardant material, which comprises the following components of: by weight, 10-80 parts of ethene-vinyl acetate copolymer, 5-30 parts of ethylene-octene copolymer and/or ethene-butene copolymer and/or terpolymer EP rubber, 0-100 parts of polyethylene, 1-20 parts of a polymer compatilizer, 0.5-10 parts of organosilicon polymer, 1-10 parts of a composite anti-oxidant, 0-200 parts of aluminium hydroxide and/or magnesium hydroxide and/or modified aluminium hydroxide and/or modified magnesium hydroxide, 0.1-100 parts of high molecular weight ammonium polyphosphate and/or 0.1-50 parts of a phosphate ester fire retardant and/or 0.1-50 parts of MCA. The material provided by the invention reaches American UL224VW-1 standard when applied in thermal shrinkable tubes, reaches American UL1581VW-1 standard when applied in electric wires and cables, contains no halogen or red phosphorus, and is environmentally friendly.

Modified sodium silicate binder for cold core box and preparation thereof

Abstract: The invention aims to provide a modified sodium silicate binder for a cold core box and a preparation method thereof. The binder has the advantages of wide raw material sources, no toxicity or smell and good mechanical property and is applicable to mechanized core manufacture of the cold core box and manual core manufacture. The modified sodium silicate binder comprises the following chemical compositions in percentage by mass: 20 to 30 percent of SiO, 10 to 20 percent of Na2O, 0.5 to 19 percent of K2O, 1.0 to 20 percent of modifier and the balance of water, wherein the modifier can be aluminium hydroxide and/or zinc hydroxide, or one or more of amylin, sugar, molasses, polyacrylamide, sodium polyacrylate, sodium tripolyphosphate, cellulose, humic acid, sodium humate, sorbierite, xylitol and sodium silicate are added.

Preparation method of low-sodium fine grain alumina

Abstract: The invention relates to a preparation method of low-sodium fine grain alumina, in particular to a preparation method of low-sodium submicro grain alumina used for electronic ceramics, microcrystalline ceramics, fine polishing, catalyst carriers and the like. The preparation method is characterized by taking industrial aluminium hydroxide as a raw material in the preparation process and comprising the following steps of: firstly carrying out hydrothermal phase inversion processing on aluminium hydroxide to obtain low-sodium fine grain alumina monohydrate with sodium oxide content being less than 500ppm; briquetting the obtained low-sodium fine grain alumina monohydrate, and then roasting to obtain low-sodium fine grain alumina; and finally grinding and grading, thus obtaining low-sodium submicro alumina. The preparation method of low-sodium fine grain alumina has the advantages of simple production process, wide raw material sources, low production cost, environment friendliness and the like, and can combine with the existing alumina production process and equipment to carry out hydrothermal processing, thus effectively simplifying the production process and lowering the production cost. The method is ideal for preparing ultra-low-sodium boehmite and alumina.

Method for comprehensive utilization of aluminum-containing material

Abstract: The invention relates to a method for preparing aluminum oxide and other products by aluminum-containing materials of bauxite, alunite, nepheline, fly ash, kaolin, coal gangue and clay. The method comprises the following steps: (1) crushing and grinding an aluminum-containing material, carrying out mixing and baking for the treated aluminum-containing material and ammonium bisulfate; (2) carryingout dissolution and filtering for the baked clinker to obtain a crude ammonium aluminum sulfate solution and aluminum extracting residue; (3) carrying out an iron precipitating treatment for the ammonium aluminum sulfate solution with the concentration more than 1 g/L by adopting a jarosite method, then carrying out an iron precipitating treatment by a goethite method, carrying out an aluminum precipitating treatment for the resulting solution, carrying out calcination for the resulting aluminium hydroxide to prepare aluminum oxide; (4) carrying out an iron precipitating treatment for the ammonium aluminum sulfate solution with the concentration less than 1 g/L by adopting the goethite method, and carrying out an aluminum precipitating treatment to prepare aluminum oxide, or adopting a recrystallization method to carry out purification, adopting a reaction of the ammonium aluminum sulfate crystal and a ammonium carbonate solution to precipitate the aluminum to obtain ammonium aluminumcarbonate, carrying out calcination for the ammonium aluminum carbonate, and adopting a Bayer method to treat the calcined ammonium aluminum carbonate to prepare sandy aluminum oxide; (5) washing anddrying the aluminum extracting residue, wherein the dried aluminum extracting residue is adopted as the silicon dioxide product.

Alkali-free liquid setting accelerator

Abstract: The invention discloses an alkali-free liquid setting accelerator which is prepared from the following components by weight percent: 18-40% of hydroxycarboxylic acid, 1-5% of phosphoric acid, 15-30% of aluminium hydroxide, 0-5% of alkylol amine, 001-02% of defoaming agent and the balance water The alkali-free liquid setting accelerator of invention does not contain alkali metal ions, sulfate ions and other corrosive materials, is safe to use and has no bad effect on the durability of sprayed concrete, thus being capable to be used in the construction of sprayed concrete

Preparation method of hydrotreatment catalyst

Abstract: The invention discloses a preparation method of a hydrotreatment catalyst, comprising the following steps of: introducing silicon and boron additives in the way that an organic silicon source is added after aluminium hydroxide gel forming and then a boron-containing organic compound solution is added, so as to obtain silicon and boron containing aluminium hydroxide, mixing parts of an active metal component with boron-containing aluminium hydroxide by a kneading method, carrying out three-stage roasting to obtain a catalyst intermediate, loading residual part of the active metal onto the catalyst intermediate by dipping, and drying to obtain the hydrotreatment catalyst. By the adoption of the method provided by the invention, the silicon and boron additives and the active metal component are uniformly distributed on the surface of the catalyst. In addition, the active metal component has different existing forms in the catalyst when introduced in the two modes, loss rate of the catalyst activity is reduced by mutual cooperation, and running period of a device is prolonged. The catalyst has large pore volume, large specific surface area, appropriate pore structure and acidity, and is especially suitable for hydrodenitrogenation process of heavy hydrocarbon.

Preparation method of nanometer aluminium hydroxide and application thereof

Abstract: The invention discloses a preparation method of nanometer aluminium hydroxide, which adopts organic aluminium to hydrolyze and generate nanometer aluminium hydroxide; then the nanometer aluminium hydroxide is served as seed crystal, and inorganic aluminum salt is used for industrially producing nanometer aluminium hydroxide on a large scale so as to effectively ensure the stability of sintetics seed crystal. Organic aluminium can choose aluminium methoxide which has low cost and is easy to synthetize; inorganic salt can be served as basic sintetics, thus greatly lowering raw material cost; the obtained nanometer aluminium hydroxide has favourable dispersibility after modified by silane coupling agent. The nanometer aluminium hydroxide produced with the preparation method of the invention is served as inkjet printing media to ensure that color ink jet printing paper has the characteristics of water resistance, high ink adsorption speed, high gloss, bright color and the like; the nanometer aluminium hydroxide also can be served as the main component to be used in inorganic/organic composite coating, so that the coating has excellent adhesive force, hardness, corrosion resistance andthe like.

Silicone rubber material for ageing-resistant composite insulator and preparation method thereof

Abstract: The invention relates to a silicone rubber material for an ageing-resistant composite insulator and a preparation method thereof. Methyl phenyl silicone resin is added into a 110-2 methyl vinyl silicone rubber basal body, the oxidation of a pendant group is inhabited and a phenyl forms steric hindrance on a silicon oxygen chain due to the introduction of the phenyl, so that a main chain is more difficult to degrade, thereby the thermal stability of silicone rubber is further improved; a Z-6173 dispersing auxiliary agent is added into aluminium hydroxide and enters an ultrasonic jet mill, so that under the action of high-speed high-pressure airflows in different directions, a newborn surface formed from powders has reactive activity and generates chemical reaction or chemical adsorption with a dispersant, thinning and activation are simultaneously finished, the compatibility of the aluminium hydroxide and the silicone rubber is improved, the bonding force of the aluminium hydroxide andsilicone rubber molecules and the dispersivity of the aluminium hydroxide in the silicone rubber are improved, the insulator is prevented from being separated out in the operating process, the occurrence of whitening and powdering phenomena on the surface of a silicone rubber shed is eliminated, and the aging resistant performance of the silicone rubber material is improved.

Method for producing sandy alumina by fly ash

Abstract: The invention relates to a method for producing sandy alumina, especially to a method for producing sandy alumina by high-alumina fly ash. The method for producing sandy alumina by fly ash comprises the following steps of: carrying out acid-leaching on the fly ash raw material by using acid, followed by desiliconization and crystal thermal decomposition to obtain crude alumina, carrying out alkali dissolution on the crude alumina by using an alkali regulating solution, carrying out liquid-solid separation on the dissolved slurry, filtering and removing slag to obtain a sodium aluminate solution, adding aluminium hydroxide as seed into the sodium aluminate solution, cooling the sodium aluminate solution for seed precipitation so as to obtain an aluminium hydroxide precipitate, carrying out liquid-solid separation on the aluminium hydroxide precipitate, followed by washing to obtain aluminium hydroxide, and roasting aluminium hydroxide to obtain sandy alumina. By a serial production technology of preparing crude alumina by an acid method and preparing sandy alumina by an alkali method, the material cycle for alumina extraction by the acid method is less with less amount of slag; energy consumption for low-temperature alkali dissolution is low; the flow and material adoption are simple; and the quality of aluminium hydroxide and the alumina product prepared by the seed precipitation technology is high.

XPS–SIMS Surface Characterization of Aluminovanadate Oxide Catalyst Precursors Co-Precipitated at Different pH: Effect of Calcination

Abstract: X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed in a comparative study of the surface physical and chemical state of aluminovanadate oxide catalyst precursors (V–Al–O), which were precipitated in the range of pH from 5.5 to 10, after drying and calcination. Core-level photoelectron spectra, X-ray induced Auger and valence band spectra of the samples were measured so as to quantitatively evaluate the surface concentrations of the catalyst components. The binding energy shifts of the respective O 1s, V 2p and Al 2p lines were determined as a function of pH and analyzed in terms of the initial state effect related to the atomic charge and Madelung potential. The surface of the catalysts was composed of aluminum hydroxide/oxyhydroxide and of dispersed vanadium oxide species. Increasing pH was found to result in a monotonic variation of the elemental surface composition, modification of the valence band, progressive hydroxylation of the surface and increasing dispersion of vanadium oxide species. Increasing pH was also accompanied by an increase in the abundance of V4+ species, specific surface area and reducibility. Calcination in air at 500 °C gave rise to surface segregation of vanadium, changes in the valence band and partial dehydroxylation. The structural transformations in vanadium oxide species and aluminium hydroxide support and their interaction were accompanied by an increasing abundance of V–O–Al bonds. The net result of the restructuring was a decrease in the specific surface area and reducibility of the calcined catalysts. The enhancement of the catalytic activity in propane oxidative dehydrogenation demonstrated by V–Al–O samples with increasing precipitation pH and after calcination was in good correlation with a growing population of the V4+ states and increasing nucleophilicity of oxygen sites.

Method for preparing high purity potassium carbonate and high purity aluminium hydroxide through Baiyun ebo potash feldspar concentrate

Abstract: The invention relates to a method for preparing high purity potassium carbonate and high purity aluminium hydroxide through Baiyun ebo potash feldspar concentrate, and belongs to the field of hydrometallurgy. According to the present invention, the potash feldspar concentrate is adopted as a raw material, wherein the potash feldspar concentrate is sorted from the Baiyun ebo potassium-rich slate, and has the purity more than 95%; the new process adopts lime sintering and stepwise leaching method for preparing the high purity potassium carbonate and the high purity aluminium hydroxide. The purity of the potassium carbonate is more than 99%, the recovery rate of the potassium carbonate is more than 90%; the aluminium hydroxide meets the state grade 1 standard, and the recovery rate of the aluminium hydroxide is more than 85%; the process provided by the present invention is simple, the method is applicable for the industrial production, and good economic benefits are provided.

Preparation method of ultrahigh-purity and superfine aluminium oxide powder

Abstract: The invention relates to a preparation method of ultrahigh-purity and superfine alumina powder. The preparation method comprises the following process steps of: (1) injecting a high-purity aluminium sheet, isopropanol and a catalyst into a synthetic reaction tower to generate gaseous aluminium isopropoxide; cooling gaseous aluminium isopropoxide into liquid aluminium isopropoxide by virtue of a condenser; (2) injecting liquid aluminium isopropoxide into a reduced pressure distillation purification tank for evaporating to form steam, injecting the steam to a material receiving tank to become liquid ultrahigh-purity aluminium isopropoxide; (3) adding ultrahigh-purity aluminium isopropoxide into a vacuum stirring and drying machine, injecting high-purity water, and carrying out hydrolysis reaction under the circulating water cooling condition, so as to obtain ultrahigh-purity aluminium hydroxide and isopropanol aqueous solution; and drying in a vacuum stirring and drying machine; and (4) placing ultrahigh-purity aluminium hydroxide powder into a corundum crucible, and calcining in an electrically pushed slab kiln until the aluminium hydroxide powder is changed into alpha-Al2O3 powder, thus preparation is completed.

Leaching process investigation of secondary aluminium dross: investigation of AlN hydrolysis behaviour in NaCl solution

Abstract: The AlN hydrolysis behaviour in NaCl solution was investigated by immersing AlN powder in deionised water, 0·3 mol L−1 NaCl aq and 0·6 mol L−1 NaCl aq at 291 K respectively. The pH value of the suspension was monitored continuously for the first 4 days, and the amount of NH3 formed within 10 days period was measured by water quality–determination of ammonium–distillation and titration method. The characterisation of the products after hydrolysis was carried out using X-ray diffraction, SEM and TEM analyses. It was shown that the hydrolysis process included a slow reaction period involving the dissolution of aluminium hydroxide layer around raw AlN particle, followed by the precipitation of aluminium hydroxide gel and the crystallisation of boehmite, bayerite and gibbsite. The effects of sodium chloride concentration on the hydrolysis behaviour are presented.

Method for selectively preparing propylene glycol from sugar-containing compound

Abstract: The present invention provides a method for highly-selectively preparing propylene glycol from a sugar-containing compound, wherein the sugar-containing compound comprises cellulose, starch, hemicellulose, sucrose, glucose, fructose, fructosan, xylose, and soluble xylooligosaccharide. According to the method, the sugar-containing compound is adopted as a reaction raw material, a three-component composite catalyst is adopted, and a one-step catalytic conversion process is performed at a temperature of 120-300 DEG C under hydrogen pressure of 0.1-15 MPa to achieve high performance, high selectivity and high yield preparation of propylene glycol from the sugar-containing compound, wherein active components of the catalyst comprise one or more than two materials selected from 8, 9, and 10 group transition metals such as iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium and platinum, one or more than two materials selected from an inorganic compound of tungsten, an organic compound of tungsten, a complex of tungsten and elementary tungsten, and one or more than two materials selected from an oxide of an alkali metal or an alkaline earth metal, a hydroxide of an alkali metal or an alkaline earth, an alkaline salt of an alkaline metal or an alkaline earth metal, aluminium hydroxide, zinc oxide, and zinc hydroxide.

Method for preparing spherical porous alumina carrier

Abstract: A method for preparing a spherical porous alumina carrier is characterized in that the preparing steps include dissolving aluminium hydroxide by a hydrochloric acid or sulfuric acid solution to obtain an aluminum ion acid aqueous solution; dropwise introducing a sodium hydroxide solution into the obtained acid aqueous solution in a hydrothermal system, performing a punchy stirring, finally stabilizing the potential of hydrogen (pH) value in a range between 3.0 and 5.0, and then performing an ageing treatment at the normal temperature; vigorously stirring a solution after ageing in the hydrothermal system, rapidly adding a template agent solution, and then introducing a reaction auxiliary; continuously stirring and reacting the above mixed system completely in the hydrothermal system; obtaining a precursor powder by a spray drying after fully washing and filtering with deionized water; and calcining the precursor powder to obtain spherical porous activated aluminium oxide. By means of the method, the prepared spherical porous alumina carrier is good in pore passage structure, large in pore volume and specific surface area and capable of meeting industrial application requirements of a heterogeneous catalysis, a tail gas purification and an adsorption separation.

Vaccine composition with aluminium hydroxide nanoparticles

Abstract: A vaccine composition comprising at least one antigen and one adjuvant, characterized in that the adjuvant comprises sterile-filterable nanoparticles comprising pseudo-boehmite and polyacrylate.

Method for the preparation of layered double hydroxides

Abstract: A method is disclosed for the preparation of layered double hydroxides with particles having a rod-like morphology by preparing a precursor of rod-like aluminium hydroxide particles and contacting the precursor with an aqueous lithium salt. Preferably, the precursor will be prepared by templated hydrothermal synthesis. Also disclosed are lithium aluminium layered double hydroxides with rod-like particles and composites comprising such particles.

Preparation method for aluminium oxide

Abstract: The invention discloses a preparation method for aluminium oxide. The preparation method comprises the following steps of: (1), preparing aluminium isopropoxide through the reaction of Al and anhydrous isopropyl alcohol; (2), hydrolyzing the aluminium isopropoxide acquired in the step (1) with hydrous isopropyl alcohol, wherein the molar ratio of the aluminium isopropoxide to the water is 1 to (1-2); (3), reducing pressure to distill out the anhydrous isopropyl alcohol, and drying the anhydrous isopropyl alcohol to acquire the powder; (4), adding distilled water to the powder acquired in the step (3), wherein the molar ratio of the added quantity of the distilled water to the aluminium isopropoxide in the step (2) is (2-5) to 1; and (5), reducing the pressure to distill out hydrous isopropyl alcohol, drying the hydrous isopropyl alcohol to acquire aluminium hydroxide powder. Hydrolysis is carried out twice in the preparation method, wherein the anhydrous isopropyl alcohol is acquired in the first partial hydrolysis for synthesizing the aluminium isopropoxide; and the hydrous isopropyl alcohol is acquired in the second hydrolysis for hydrolyzing the aluminium isopropoxide, so that the recycling is achieved to reduce the cost for preparing high-purity aluminium oxide powder by an alkoxide process, thus, conditions are created for the industrial development in preparing the aluminium oxide by the alkoxide process.

Method of obtaining aluminium oxide applicable for manufacturing artificial corundum crystals

Abstract: FIELD: chemistry. ^ SUBSTANCE: in order to obtain aluminium oxide applicable for manufacturing artificial corundum crystals, aluminium of 99.95-99.999% purity is dissolved in solution of chlorides of ammonium, sodium or their mixture, which contains 5-150 g/l of chloride-ions, at temperature 20-95C with reverse supply of constant current at current density 0.045-0.12 A/cm2. Electrode surface is washed with rate 60-1400 l/(m2h) with electrolyte, circulating in outer contour. Formation of dense aluminium hydroxide sediment is performed in collection expansion tank with expansion coefficient 25-400. Aluminium hydroxide is separated from electrolyte by centrifugation with rotation rate 20-60 rev/s. Sediment is washed in specially prepared water with specific resistance 0.4-18 megaohmcm. Washed sediment is dried in flow of hot air with temperature 100-400C and annealed in electric furnace until aluminium oxide is obtained. ^ EFFECT: invention makes it possible to increase product output and electrolyser productivity, improve quality of obtained aluminium oxide. ^ 7 cl, 1 tbl

Water-dispersion paint composition

Abstract: FIELD: chemistry. ^ SUBSTANCE: water-dispersion paint composition contains a polymer acrylic component, pigments, an organic thickener and a surfactant. Besides water, biocidal and coalescent additives, the composition contains corrosion inhibitors of prolonged and instant action, a thixotropic rheologic additive, a plasticiser - dibutylphthalate, antipyrene and additional property modifiers of the film coating of the composition in form of fractionated microbarite, magnesium hydroxide, aluminium hydroxide, microwollastonite and fractionated micromica. ^ EFFECT: high fire-resistance of coatings and improved anti-corrosion properties of metals - ferrous, aluminium, brass, enamelled surfaces during prolonged operation with retention of decorative properties. ^ 4 tbl, 1 ex