Aluminium oxide
Identifiers
CAS number	1344-28-1
Properties
Molar mass	101.96 g/mol
Density	3.97 g cm−3, solid
Melting point	2054 °C Alumina Limited is a public company listed on the Australian Stock Exchange. ... Image File history File links Size of this preview: 800 × 553 pixel Image in higher resolution (1100 × 760 pixel, file size: 378 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Aluminium oxide ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...
Boiling point	2980 °C [1] Italic text This article is about the boiling point of liquids. ...
Solubility in water	insoluble
Structure
Coordination geometry	octahedral
Thermochemistry
Std enthalpy of formation ΔfHo298	−1675.7 kJ mol−1
Standard molar entropy So298	50.92 J mol−1 K−1
Hazards
MSDS	External MSDS
EU classification	Not listed.
Flash point	non-flammable
Related Compounds
Other anions	aluminium hydroxide
Other cations	boron trioxide gallium oxide indium oxide thallium oxide
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Aluminium oxide is an amphoteric oxide of aluminium with the chemical formula Al₂O₃. It is also commonly referred to as alumina in the mining, ceramic and materials science communities. It is produced by the Bayer process from bauxite; its most significant use is in the production of aluminium metal. Being very hard, it is used as an abrasive. Having a high melting point, it is used as a refractory material.^[2] Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... The coordination geometry of an atom is the geometrical pattern formed by its neighbors in a molecule or a crystal. ... An octahedron (plural: octahedra) is a polyhedron with eight faces. ... The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 atmosphere... In chemistry, the standard molar entropy is the entropy content of one mole of substance, under conditions of standard temperature and pressure. ... An example MSDS in a US format provides guidance for handling a hazardous substance and information on its composition and properties. ... This page provides supplementary chemical data on aluminium oxide. ... Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances (as amended) is the main European Union law concerning chemical safety. ... For other uses, see Flash point (disambiguation). ... This article is about the electrically charged particle. ... Aluminium hydroxide, Al(OH)3, is the most stable form of aluminium in normal conditions. ... This article is about the electrically charged particle. ... Boron oxide is one of the oxides of boron. ... Indium(III) oxide (In2O3) is a chemical compound, an amphoteric oxide of indium. ... This article lacks information on the importance of the subject matter. ... This page provides supplementary chemical data on aluminium oxide. ... This page provides supplementary chemical data on aluminium oxide. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... The relative dielectric constant of a material under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. ... This page provides supplementary chemical data on aluminium oxide. ... This page provides supplementary chemical data on aluminium oxide. ... Ultraviolet-Visible Spectroscopy or Ultraviolet-Visible Spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... Infrared spectroscopy (IR spectroscopy) is the subset of spectroscopy that deals with the infrared region of the electromagnetic spectrum. ... Nuclear magnetic resonance spectroscopy most commonly known as NMR spectroscopy is the name given to the technique which exploits the magnetic properties of certain nuclei. ... Mass spectrometry (previously called mass spectroscopy (deprecated)[1] or informally, mass-spec and MS) is an analytical technique used to measure the mass-to-charge ratio of ions. ... The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... An amphoteric oxide is an oxide that is amphoteric, that is, it can act either as an acid or a base. ... Aluminum redirects here. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Aluminum redirects here. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Chuquicamata, the second largest open pit copper mine in the world, Chile. ... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ... The Materials Science Tetrahedron, which often also includes Characterization at the center Materials science or Materials Engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering. ... The Bayer process is the principal industrial means of producing alumina, itself important in the Hall-Héroult process for producing aluminum. ... Bauxite with penny Bauxite with core of unweathered rock Bauxite is an aluminium ore. ... Aluminum redirects here. ... The term refractory can refer to multiple things: A refractory clergyman is one who refused to swear an oath to the French Revolution-era French state under the Civil Constitution of the Clergy. ...

Natural occurrence

Corundum is the naturally occurring crystalline form of aluminium oxide. Rubies and sapphires are gem-quality forms of corundum with their characteristic colors due to trace impurities in the corundum structure. Corundum (from Tamil kurundam) is a crystalline form of aluminium oxide and one of the rock-forming minerals. ... Crystal (disambiguation) Insulin crystals A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... This article does not cite any references or sources. ... For other uses, see Sapphire (disambiguation). ...

Properties

Aluminium oxide is an electrical insulator but has a relatively high thermal conductivity. In its most commonly occurring crystalline form, called corundum or α-aluminum oxide, its hardness makes it suitable for use as an abrasive and as a component in cutting tools.^[2] This article or section is in need of attention from an expert on the subject. ... Corundum (from Tamil kurundam) is a crystalline form of aluminium oxide and one of the rock-forming minerals. ... An abrasive is a material, often a mineral, that is used to shape or finish (see metal polishing and wood finishing) a workpiece through rubbing which leads to part of the workpiece being worn away. ... In the context of Metalworking, a Cutting Tool, is any tool that is used to remove metal from the workpiece by means of shear deformation. ...

Aluminium oxide is responsible for metallic aluminium's resistance to weathering. Metallic aluminium is very reactive with atmospheric oxygen, and a thin passivation layer of alumina quickly forms on any exposed aluminium surface. This layer protects the metal from further oxidation. The thickness and properties of this oxide layer can be enhanced using a process called anodising. A number of alloys, such as aluminium bronzes, exploit this property by including a proportion of aluminium in the alloy to enhance corrosion resistance. The alumina generated by anodising is typically amorphous, but discharge assisted oxidation processes such as plasma electrolytic oxidation result in a significant proportion of crystalline alumina in the coating, enhancing its hardness. Weathering is the decomposition of rocks, soils and their minerals through direct contact with the Earths atmosphere. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Passivation is the process of making a material passive in relation to another material prior to using the materials together. ... These inexpensive carabiners have an anodised aluminium surface that has been dyed and are made in many colors. ... An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resultant material has metallic properties. ... Aluminium bronze is a type of bronze in which aluminium is the main alloying metal added to copper. ... An amorphous solid is a solid in which there is no long-range order of the positions of the atoms. ... Plasma electrolytic oxidation, or microarc oxidation, is an electrochemical surface treatment process for metals. ... Look up hardness in Wiktionary, the free dictionary. ...

Aluminium oxide was taken off the United States Environmental Protection Agency's chemicals lists in 1988. Aluminum oxide is on EPA's TRI list if it is a fibrous form.^{[citation needed]} EPA redirects here. ... Year 1988 (MCMLXXXVIII) was a leap year starting on Friday (link displays 1988 Gregorian calendar). ...

[[==Crystal structure== == The most common form of crystalline alumina, α-aluminum oxide, is known as corundum. Corundum has a trigonal Bravais lattice with a space group of R-3c (number 167 in the International Tables). The oxygen ions nearly form a hexagonal close-packed structure with aluminum Bold textions filling two-thirds of the octahedral interstices. ==]][[Media
^{Superscript text#REDIRECT [[#REDIRECT Insert text} Corundum (from Tamil kurundam) is a crystalline form of aluminium oxide and one of the rock-forming minerals. ... Category: ...

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Production

Aluminium oxide, also known as alumina, is the main component of bauxite, the principal ore of aluminium. The largest manufacturers in the world of alumina are Alcoa, Alcan and Rusal.^{[citation needed]} Companies which specialise in the production of speciality aluminium oxides and aluminium hydroxides include Alcan and Almatis. The bauxite ore is made up of impure Al₂O₃, Fe₂O₃, and SiO₂. Bauxite is purified by the Bayer process: An oxide is a chemical compound containing at least one oxygen atom and other elements. ... Bauxite with penny Bauxite with core of unweathered rock Bauxite is an aluminium ore. ... Iron ore (Banded iron formation) Manganese ore Lead ore Gold ore An ore is a volume of rock containing components or minerals in a mode of occurrence which renders it valuable for mining. ... Aluminum redirects here. ... Manufacturing (from Latin manu factura, making by hand) is the use of tools and labor to make things for use or sale. ... This article is about the company. ... Alcan (ALaska CANada) is also one of the common names for the Alaska Highway that connects Dawson Creek, British Columbia, with Fairbanks, Alaska. ... RUSAL is Russias biggest aluminium producer with a 75% share in the domestic aluminium market. ... The Bayer process is the principal industrial means of producing alumina, itself important in the Hall-Héroult process for producing aluminum. ...

Al₂O₃ + 3 H₂O + 2 NaOH → 2NaAl(OH)₄

The Fe₂O₃ does not dissolve in the base. The SiO₂ dissolves as silicate Si(OH)₆^2-. Upon filtering, Fe₂O₃ is removed. When the Bayer liquor is cooled, Al(OH)₃ precipitates, leaving the silicates in solution. The mixture is then calcined (heated strongly) to give aluminium oxide:^[2] Calcination (also referred to as Calcining) is thermal treatment process applied to ores and other solid materials in order to bring about a thermal decomposition, phase transition, or removal of a volatile fraction. ...

2Al(OH)₃ + heat → Al₂O₃ + 3H₂O

The formed Al₂O₃ is alumina.

Uses

Alumina output in 2005

Annual world production of alumina is approximately 45 million tonnes, over 90% of which is used in the manufacture of aluminium metal.^[2] Major uses for aluminium hydroxide include the manufacture of water treatment chemicals such as aluminium sulfate, aluminium chlorohydrate, and sodium aluminate. Large tonnages are also used in the manufacture of zeolites, coating titania pigments and as a fire retardants/smoke suppressant. The major uses of speciality aluminium oxides are in refractories, ceramics, polishing and abrasive applications. Minor uses include use in toothpaste formulations, and as a medium for chromatography. In this latter application alumina is available in the so-called Brockmann types neutral, basic (pH 9.5) and acidic (pH 4.5 when in water). Aluminium oxide is also used in preparation of coating suspensions in compact fluorescent lamps. Image File history File links Size of this preview: 800 × 351 pixelsFull resolution (1425 × 625 pixel, file size: 60 KB, MIME type: image/png)This bubble map shows the global distribution of alumina output in 2005 as a percentage of the top producer (Australia - 17,704,000 tonnes). ... Image File history File links Size of this preview: 800 × 351 pixelsFull resolution (1425 × 625 pixel, file size: 60 KB, MIME type: image/png)This bubble map shows the global distribution of alumina output in 2005 as a percentage of the top producer (Australia - 17,704,000 tonnes). ... Aluminium hydroxide, Al(OH)3, is the most stable form of aluminium in normal conditions. ... Aluminium sulfate is a widely used industrial chemical. ... Aluminium chlorohydrate is a group of salts having the general formula AlnCl(3n-m)(OH)m. ... -1... Categories: Silicate minerals | Mineral stubs ... For the Second Person album, see Chromatography (album). ... For other uses, see PH (disambiguation). ... A spiral type compact fluorescent lamp. ...

Al₂O₃ is also used in fluoride water filters. It is one of the few methods available to filter water-soluble fluorides out of water.

Aluminum oxide is also used as a material in hip replacements.^[2] This article does not cite any references or sources. ...

Abrasive

Because of aluminium oxide's great hardness (position 9 on the Mohs scale of mineral hardness), it is widely used as an abrasive, even as a much less expensive substitute for industrial diamond. Many types of sandpaper use aluminium oxide crystals. In addition, its low heat retention and specific heat makes it widely used in almost all grinding operations, particularly cutoff tools. The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. ... An abrasive is a material, often a mineral, that is used to shape or finish (see metal polishing and wood finishing) a workpiece through rubbing which leads to part of the workpiece being worn away. ... // A scattering of round-brilliant cut diamonds shows off the many reflecting facets. ... sheets of sandpaper Sandpaper is a form of paper where an abrasive material has been fixed to its surface; it is part of the coated abrasives family of abrasive products. ... Turned chess pieces Metalworking is the craft and practice of working with metals to create structures or machine parts. ...

Aluminium oxide powder is used in certain CD/DVD cleaning kits. Alumina will polish the media surface, leaving it clean and relatively scratch-free. CD may stand for: Compact Disc Canadian Forces Decoration Cash Dispenser (at least used in Japan) CD LPMud Driver Centrum-Demokraterne (Centre Democrats of Denmark) Certificate of Deposit České Dráhy (Czech Railways) Chad (NATO country code) Chalmers Datorförening (computer club of the Chalmers University of Technology) a 1960s... DVD (also known as Digital Versatile Disc or Digital Video Disc) is a popular optical disc storage media format. ... Look up scratch in Wiktionary, the free dictionary. ...

Most pre-finished wood flooring now uses aluminum oxide as a hard protective coating. Finishing is the procedure that some single malt Scotch whisky undergoes whereby the spirit is matured in a cask of a particular origin and then spends time in a cask of different origin. ... For other uses, see Wood (disambiguation). ... An example of a flooring job Flooring is the general term for a permanent covering of a floor. ... A coating is a covering that is applied to an object to protect it or change its appearance. ...

In 1961, GE developed "Lucalox", a transparent alumina used in sodium vapor lamps.^{[citation needed]} A sodium vapor lamp is a gas discharge lamp which uses sodium in an excited state to produce light. ... A LPS / SOX streetlight at full power A sodium vapor lamp is a gas discharge lamp which uses sodium in an excited state to produce light. ...

In August 2004, scientists in the United States working for 3M developed a technique for making an alloy of aluminium oxide and rare earth elements to produce a strong glass called transparent alumina. Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... 3M Company (NYSE: MMM), formerly Minnesota Mining and Manufacturing Company until 2002, is an American corporation with a worldwide presence. ... An alloy is a homogeneous hybrid of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ... Rare earth ore Rare earth elements and rare earth metals are trivial names sometimes applied to a collection of 17 chemical elements in the periodic table, namely scandium, yttrium, and the lanthanides. ... This article is about the material. ... Corundum (from Tamil kurundam) is a crystalline form of aluminium oxide and one of the rock-forming minerals. ...

As discussed above (in the "Properties" section), alumina can be grown as a coating on aluminium by anodising or by plasma electrolytic oxidation. These inexpensive carabiners have an anodised aluminium surface that has been dyed and are made in many colors. ... Plasma electrolytic oxidation, or microarc oxidation, is an electrochemical surface treatment process for metals. ...

Aluninum oxide is an abrasive used in toothpaste.

See also

• Bayer process
• List of Alumina Refineries

The Bayer process is the principal industrial means of producing alumina, itself important in the Hall-Héroult process for producing aluminum. ... This is a list of alumina refineries in the world. ...

References

1. ^ Mallickrodt Backer, MSDS. Aluminum Oxide: Material Safety Data Sheet (A28440).
2. ^ ^{a b c d e} Alumina (Aluminium Oxide) – The Different Types of Commercially Available Grades. The A to Z of Materials. Retrieved on 2007-10-27.

Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 300th day of the year (301st in leap years) in the Gregorian calendar. ...

External links

• International Chemical Safety Card 0351
• PhysicsWeb article on Transparent alumina