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Aluminium (or aluminum in North American English) is a chemical element; it has symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has a great affinity towards oxygen, forming a protective layer of oxide on the surface when exposed to air.
Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula Al 2 O 3. It is the most commonly occurring of several aluminium oxides, and specifically identified as aluminium oxide. It is commonly called alumina and may also be called aloxide, aloxite, or alundum in various forms and ...
An alum (/ ˈ æ l ə m /) is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula X Al(SO 4) 2 ·12 H 2 O, such that X is a monovalent cation such as potassium or ammonium. [1] By itself, "alum" often refers to potassium alum, with the formula KAl(SO 4) 2 ·12 H 2 O.
Aluminium's electropositive behavior, high affinity for oxygen, and highly negative standard electrode potential are all more similar to those of scandium, yttrium, lanthanum, and actinium, which have ds 2 configurations of three valence electrons outside a noble gas core: aluminium is the most electropositive metal in its group. [1] Aluminium ...
There are many mixed oxides containing aluminium where there are no discrete or polymeric aluminate ions. The spinels with a generic formula A 2+ B 3+ 2 O 2− 4 that contain aluminium as Al 3+, such as the mineral spinel itself, MgAl 2 O 4 are mixed oxides with cubic close packed O atoms and aluminium Al 3+ in octahedral positions.
Note that the term aircraft aluminium or aerospace aluminium usually refers to 7075. [65] [66] 4047 aluminium is a unique alloy used in both the aerospace and automotive applications as a cladding alloy or filler material. As filler, aluminium alloy 4047 strips can be combined to intricate applications to bond two metals. [67]
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer.Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al 2 O 3), the rest being a mixture of silica, various iron oxides, and titanium dioxide. [1]
Aluminium silicate is a type of fibrous material made of aluminium oxide and silicon dioxide, (such materials are also called aluminosilicate fibres). These are glassy solid solutions rather than chemical compounds. The compositions are often described in terms of % weight of alumina, Al 2 O 3 and silica, SiO 2. Temperature resistance increases ...