Aluminum oxide hydrate

Mag nesia. ndAlumina. Suspension. A mixture of salts, available as Maalox, Mylanta, Gelusil, and Aludrox, contains magnesium hydroxide [1309-42-8] Mg(OH)2, and variable amounts of aluminum oxide in the form of aluminum hydroxide and hydrated aluminum oxide, ie, 2.9—4.2% magnesium hydroxide and 2.0—2.4% aluminum oxide, Al O, for a mixture of 4.9—6.6% combined magnesium hydroxide and aluminum oxide. This mixture may contain a flavoring and antimicrobial agents in a total amount not to exceed 0.5% (see Aluminum compounds, aluminum oxide). 

Activated alumina Hydrated aluminum oxide, a granular desiccant activated at high temperature that absorbs moisture and gases. 

Aluminum (third most abundant element) is found as the Al+ ion in oxides and as the complex ion AlFImportant minerals are bauxite, which is best described as a hydrated aluminum oxide, Al203-.xH20, and cryolite, NaaAlFs. The element is readily oxidized and is not found in an uncombined state in nature. 

Activated aluminas. Activated alumina is a porous form of aluminum oxide (A1203) with high surface area, manufactured by heating hydrated aluminum oxide to around 400°C in air. Activated aluminas are mainly used to dry gases and liquids, but can be used to adsorb gases and liquids other than water. 

One of the most important electrolytic processes is the extraction of aluminum from an ore called bauxite. This ore is mainly composed of hydrated aluminum oxide, AI2O3 XH2O. (The x in the formula indicates that the number of water molecules per formula unit is variable.) In industry, the scale of production of metals is huge. The electrolytic production of aluminum is over two million tonnes per year in Canada alone. As you know from Faraday s law, the amount of a metal produced by electrolysis is directly proportional to the quantity of electricity used. Therefore, the industrial extraction of aluminum and other metals by electrolysis requires vast quantities of electricity. The availability and cost of electricity greatly influence the location of industrial plants. 

Hydrated aluminum oxide is a preferred flame refardanf fhaf liberates its water of hydrafion when exposed to flames, in contrast to chlorinated materials, which give off toxic gases as by-products. The paraffin oil is a processing aid that enhances the ability to extrude such materials. The silane is a coupling agent that improves the interaction between the polymers and the aluminum trihydrate. Trimethylolpropane trimethacrylate (TMPT) enhances the radiation response. 

Sensing chemical species is a much more difficult task than the measurement of mechanical variables such as pressure, temperature, and flow, because in addition to requirements of accuracy, stability, and sensitivity, there is the requirement of specificity. In the search for chemically-specific interactions that an serve as the basis for a chemical sensor, investigators should be aware of a variety of possible sensor structures and transduction principles. This paper adresses one such structure, the charge-flow transistor, and its associated transductive principle, measurement of electrical surface impedance. The basic device and measurement are explained, and are then illustrated with data from moisture sensors based on thin films of hydrated aluminum oxide. Application of the technique to other sensing problems is discussed. 

Application to Moisture Measurement with Hydrated Aluminum Oxide Films... 

Figure 8. Typical comparison between experimental data (crosses) and calculated transfer function (circles) for CFT coated with hydrated aluminum oxide, measured at room temperature in an ambient dew point of -16.9 °C. Reproduced with permission from reference 18. Copyright 1982 Institute of Electrical and Electronics Engineers.

Bauxite mineral matter used as a treating agent hydrated aluminum oxide formed by the chemical weathering of igneous rocks. 

Alumina trihydrate alumina hydrate alumina hydrated aluminum oxide trihydrate aluminum oxide hydrate aluminum (III) hydroxide hydrated alumina hydrated aluminum oxide3 aluminum hydrate aluminum trihydrate hydrated aluminad... 

Aluminum is present in many primary minerals. The weathering of these primary minerals over time results in the deposition of sedimentary clay minerals, such as the aluminosilicates kaolinite and montmorillonite. The weathering of soil results in the more rapid release of silicon, and aluminum precipitates as hydrated aluminum oxides such as gibbsite and boehmite, which are constituents of bauxites and laterites (Bodek et al. 1988). Aluminum is found in the soil complexed with other electron rich species such as fluoride, sulfate, and phosphate. 

The one exception where certain fillers can provide electrical property improvement is in arc resistance. Here hydrated aluminum oxide and hydrated calcium sulfates will improve arc resistance if cure is sufficiently low to prevent dehydration of the filler particles. Electrical-grade fillers generally improve the arc resistance of cured epoxy systems, as indicated in Table 9.10. 

The lightness and relative ease of fabrication of aluminum and its alloys are factors favoring the use of these materials. Aluminum resists attack by acids because a surface film of inert hydrated aluminum oxide is formed. This film adheres to the surface and offers good protection unless materials which can remove the oxide, such as halogen acids or alkalies, are present. 

Unlike divalent oxides, the solubility of alumina is low and hence some warm temperature treatment is required. In addition, rather than using lower solubility phosphate solutions such as ammonium and potassium phosphate solutions, phosphoric acid solution is directly used. Wagh et al. [ 17] employed a thermodynamic analysis to study the elfect of the temperature on the solubility of individual phases of alumina on the formation of its phosphate phases during heat treatment where solubility of hydrated aluminum oxide, viz., hydrargillite (A1203-3H20) is enhanced, and that contributes further to the formation of berlinite phase. They confirmed this by differential thermal analysis (DTA) and X-ray diffraction (XRD) analysis on samples heated beyond 118°C. 

Partitioning and mobility of metal ions, metal complexes, and ligands in soils or sediments are affected by their adsorption onto a variety of substrates. As mentioned earlier (see Section 6.3.1), natural oxides offer suitable adsorption sites for some of these species and may even undergo dissolution as a result. Here, an understanding of the bonding phenomena is crucial. For example, the adsorption of [Co(III)EDTA] (here written as [ML]-) on hydrated aluminum oxide surfaces (written as =A10H) can be represented as ... 

SYNS AF 260 ALCOA 331 ALUMIGEL ALUMINA HYDRATE ALUMINA HYDRATED ALUMINA TRIHYDRATE a-ALUMINA TRIHYDRATE ALUMINIC ACID ALUMINLLM HYDRATE ALUMINUM(III) HYDROXIDE ALUMINUM HYDROXIDE GEL ALUMINUM OXIDE HYDRATE ALUMINUM OXIDE TRIHYDRATE ALUMINUM TRIHYDRAT ALUMINUM TRIHYDROXIDE ... 

The principal ore of aluminum is bauxite, a mixture of hydrated aluminum oxides (AlKOg, Al(OH)g). The metal is won from the ore by an electrolytic process, described in Chapter 14, and is sometimes further purified by electrolysis. 

Bauxite is a mixture of aluminum minerals [AlHO., Al(OH)g], Which contains some iron oxide. It is purified by treatment with sodium hydroxide solution, which dissolves hydrated aluminum oxide, as the aluminate ion, Al(OH)4, but does not dissolve iron oxide ... 

Aluminum oxide is used mainly in tablet formulations. It is used for decoloring powders and is particularly widely used in antibiotic formulations. It is also used in suppositories, pessaries, and urethral inserts. Hydrated aluminum oxide (see Section 18) is used in mordant dyeing to make lake pigments, in cosmetics, and therapeutically as an antacid. 

A specification for aluminum oxide is included in Japanese Pharmaceutical Excipients 2004 (JPE), see Table I. A specification for light aluminum oxide is also included. The PhEur 2005 includes a specification for hydrated aluminum oxide that contains the equivalent of 47.0-60.0% of AI2O3. The EINECS number for aluminum oxide is 215-691-6. 

The most important source of aluminum is the mineral bauxite. Bauxite consists mostly of hydrated aluminum oxide. 

In the PCUK process calcined hydrated aluminum oxide is reacted with a mixture of hydrogen fluoride and furnace gas. The hydrogen fluoride is produced in situ from fluorspar and sulfuric acid in a directly heated rotary tube furnace. The resulting mixture of hydrogen fluoride and furnace gases is reacted with calcined aluminum hydroxide to aluminum fluoride in a fluidized bed reactor. 

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