Aluminum hydroxide

Aluminum hydroxide, white solid, is a typical amphoteric hydroxide that is insoluble in water but soluble in acid or alkali. It can be transformed into alumina after heated in the air for dehydration, which is important for alumina production. Aluminum hydroxide is a widely used chemical product, and it is mainly used as plastic and polymer fillers, blanket flame retardant and binder, epoxy resin filler, toothpaste fillers, glass ingredients as well as paper color fillers and coatings. It can b

Aluminum hydroxide, insoluble in water, soluble in dilute mineral acids and alkali hydroxides (4 % suspension in water), white, amorphous powder. For other relevant properties and production, see→Aluminum Oxide, Chap. 1.1. Available as Al(OH)3·nH2O (algedrate) and algedrate hexitol complex.

Aluminum hydroxide adjuvant is a white hydrogel that sediments slowly and forms a clear supernatant.

aluminium hydroxide: A white crystalline compound, Al(OH)3; r.d. 2.42-2.52. The compound occurs naturally as the mineral gibbsite (monoclinic). In the laboratory it can be prepared by precipitation from solutions of aluminium salts. Such solutions contain the hexaquoaluminium( III) ion with six water molecules coordinated, [Al(H2O)6]3+. In neutral solution this ionizes:[Al(H2O)6]3+→H++ [Al(H2O)5OH]2+The presence of a weak base such as S2-or CO32-(by bubbling hydrogen sulphide or carbon dioxide through the solution) causes further ionization with precipitation of aluminium hydroxide[Al(H2O)6]3+(aq)→ Al(H2O)3(OH)3(s)+ 3H+(aq)The substance contains coordinated water molecules and is more correctly termed hydrated aluminium hydroxide. In addition, the precipitate has water molecules trapped in it and has a characteristic gelatinous form. The substance is amphoteric. In strong bases the aluminate ion is produced by loss of a further proton:Al(H2O)3(OH)3(s)+ OH-(aq)→[Al(H2O)2(OH)4]-(aq)+ H2O(l)On heating, the hydroxide transforms to a mixed oxide hydroxide, AlO.OH (rhombic; r.d. 3.01). This substance occurs naturally as diaspore and boehmite. Above 450℃ it transforms to γ-alumina.In practice various substances can be produced that are mixed crystalline forms of Al(OH)3, AlO.OH, and aluminium oxide (Al2O3) with water molecules. These are known as hydrated alumina. Heating the hydrated hydroxide causes loss of water, and produces various activated aluminas, which differ in porosity, number of remaining -OH groups, and particle size. These are used as catalysts (particularly for organic dehydration reactions), as catalyst supports, and in chromatography. Gelatinous freshly precipitated aluminium hydroxide was formerly widely used as a mordant for dyeing and calico printing because of its ability to form insoluble coloured lakes with vegetable dyes.

Poison by intraperitoneal route. Human systemic effects by ingestion: fever, osteomalacia, and gastrointestinal effects. When coprecipitated with bismuth hydroxide and reduced by H2, it is violently flammable in air. Incompatible with chlorinated rubber.

The ammonium bicarbonate method combines sulfuric acid with aluminum powder or aluminum ash to produce aluminum sulfate, and then undergoes a double decomposition reaction with ammonium bicarbonate to produce aluminum hydroxide. Its 2Al(OH)3+3H2SO4→A12(SO4)3+6H2OA12(SO4)3+6NH4HCO3→2AI(OH)3++3(NH4)2SO4+6CO2↑Sodium aluminate caustic soda and aluminum ash to 2:1 The reaction is carried out at a ratio above 100°C to prepare a sodium aluminate solution. Sulfuric acid and aluminum ash are reacted at a ratio of 1.25:1 at 110°C to prepare an aluminum sulfate solution. Then, the sodium aluminate solution and the aluminum sulfate solution were neutralized to pH 6.5 to form aluminum hydroxide precipitate, washed with water and pressure filtered, dried at 70-80°C for 12 hours, and then crushed to obtain a finished aluminum hydroxide product. A12O3+2NaOH→2NaAO2+H2OAl2O3+3H2SO4→A12(SO4)3+3H2O6NaAIO2+A12(SO4)3+12H2O→8Al(OH)3↓+3Na2SO4 recovery method After filtering and removing impurities, it reacts with sodium carbonate to produce aluminum hydroxide, which is then filtered, washed and dried to obtain aluminum hydroxide product. Its 2A1C13+3Na2CO3+3H2O→2AI(OH)3↓+6NaCl+3CO2↑

Mainly used as an Active medicament in an Antacid Formulations, also used in manufacturing of Lake Colors, Inks, glass, effluent treatment, and fire retardants.
1. Chemical raw materials
Aluminum hydroxide has many advantages including large-scale production, adequate raw materials, high product purity and good solubility in acid. Therefore, aluminum hydroxide can be used as an important raw material for the preparation of aluminum salts, such as barium aluminate, aluminum sulfate and so on.
2. Flame retardants
Aluminum hydroxide powder is commonly regarded as an ideal flame retardant filler for plastics, unsaturated polyester, rubber and other organic polymers because of its filling, flame retardant and smoke-eliminating functions and non-toxic property. Flame retardant mechanism of aluminum hydroxide is as follows: when the temperature exceeds 200 ℃, the aluminum hydroxide begin to perform endothermic decomposition and release three crystal water, and its decomposition rate reaches the largest at 250℃.

This reaction is a strong endothermic reaction, thereby inhibiting the polymer temperature rise, reducing its decomposition rate and only producing water vapor, not generating toxic and harmful gases.
3. Ceramics
Aluminum hydroxide can transform into alumina, which has high thermal chemical stability, thermal strength, creep resistance and dielectric properties and low thermal expansion coefficient. Alumina is an important material for the synthesis of ceramics. In the process of ceramic synthesis, we can control the phase formation of the composite by aluminum hydroxide activation and crystallization process controlling.
4. Sewage treatment
Aluminum hydroxide exists in water mainly in form of Al(OH)4-, which can precipitate toxic heavy metals in sewage by coprecipitation method to achieve the effect of water purification after further filter. Aluminum hydroxide has a high specific surface area, and can adsorb colloid, suspended solids, dyes and organic substances in sewage on its surface.
5. Medicine
Aluminum hydroxide can neutralize gastric acid and is non-toxic, for which it is always used as the traditional medicine for the treatment of stomach. The aluminum hydroxide as adjuvant can also improve the immunogenicity of the vaccine, the action mechanism of which is as follows: aluminum hydroxide adsorbs antigen on its surface to allow the antigen slow release so that it can play the role of extending efficacy.
6. Catalyst carrier
In the preparation of aluminum hydroxide, we can obtain various target products with diffrernt surface area, pore volume, pore structure and crystal structure by controlling the temperature, concentration and pH of the reactants, which can be effectively used as a catalyst carrier for the hydrogenation of unsaturated carbonyl compounds and the preparation of fullerenes and the like.
7. Paper industry
Aluminum hydroxide has high whiteness, ultrafine particle size as well as complete crystal form, and has a strong compatibility with brightening agent. Aluminum hydroxide, as an additive coating and resin, can effectively improve the whiteness, opacity, smoothness and ink absorption of coated paper. Mainly used as an Active medicament in an Antacid Formulations, also used in manufacturing of Lake Colors, Inks, glass, effluent treatment, and fire retardants. aluminum hydroxide is an inorganic compound used to make a product less transparent. It is also used by formulators as a humectant, and to soften, smooth, and protect the skin. In addition it helps control product viscosity. often found in facial masks and make-up preparations.

Mainly used as an Active medicament in an Antacid Formulations, also used in manufacturing of Lake Colors, Inks, glass, effluent treatment, and fire retardants.

aluminum hydroxide is an inorganic compound used to make a product less transparent. It is also used by formulators as a humectant, and to soften, smooth, and protect the skin. In addition it helps control product viscosity. often found in facial masks and make-up preparations.

As absorbent, in chromatography, manufacturing of glass, paper, inks, ceramics, lubricants, cosmeticsAluminum hydroxide is used as a desiccant powder, filler in paper, plastics, rubber and cosmetics. It is used as a smoke suppressant and mordant dye. It is also used in drugs as antacid and antihyperphosphatemic. It is also used as a Claus catalyst support for waterproof fabrics. It is an important starting material for the preparation of other aluminum compounds, calcined alumina, aluminum sulfate, polyaluminum chloride, zeolites, sodium aluminate, activated alumina and aluminum nitrate. In addition, it is used as a fire retardant.

Aluminum hydroxide adjuvant is prepared by the precipitation of a soluble aluminum salt by an alkali hydroxide, or the precipitation of an alkali aluminate by acid.