Sodium aluminosilicate refers to compounds which contain

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, 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 ...

silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...

and

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

, and which may also contain water. These include synthetic

amorphous In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid) is a solid that lacks the long-range order that is a characteristic of a crystal. The terms "glass" and "glassy solid" are sometimes used synonymousl ...

sodium aluminosilicate, a few naturally occurring minerals and synthetic

zeolite Zeolites are a group of several microporous, crystalline aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a meta ...

s. Synthetic amorphous sodium aluminosilicate is widely used as a food additive, E 554.

Amorphous sodium aluminosilicate

This substance is produced with a wide range of compositions and has many different applications. It is encountered as an additive E 554 in food where it acts as an anticaking (free flow) agent. As it is manufactured with a range of compositions it is not strictly a chemical compound with a fixed

stoichiometry Stoichiometry () is the relationships between the masses of reactants and Product (chemistry), products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must ...

. One supplier quotes a typical analysis for one of their products as 14SiO₂·Al₂O₃·Na₂O·3H₂O,(Na₂Al₂Si₁₄O₃₂·3H₂O). The US FDA has as of April 1, 2012 approved ''sodium aluminosilicate (sodium silicoaluminate)'' for direct contact with consumable items under 21 CFR 182.2727. Sodium aluminosilicate is used as

molecular sieve A molecular sieve is a material with pores of uniform size comparable to that of individual molecules, linking the interior of the solid to its exterior. These materials embody the molecular sieve effect, in which molecules larger than the pore ...

in medicinal containers to keep contents dry. Sodium aluminosilicate may also be listed as: * aluminium sodium salt * sodium silicoaluminate * aluminosilicic acid, sodium salt * sodium aluminium silicate * aluminum sodium silicate * sodium silico aluminate * sasil

As a problem in industrial processes

The formation of sodium aluminosilicate makes the

Bayer process 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 (Al2O3), the ...

uneconomical for

bauxite Bauxite () is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite (), boehmite (γ-AlO(OH)), and diaspore (α-AlO(OH) ...

s high in silica.

Minerals sometimes called sodium aluminosilicate

Naturally occurring minerals that are sometimes given the chemical name sodium aluminosilicate include

albite Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. It represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula . It is a tectosilicat ...

(NaAlSi₃O₈, an end-member of the

plagioclase Plagioclase ( ) is a series of Silicate minerals#Tectosilicates, tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continu ...

series) and jadeite (NaAlSi₂O₆).

Synthetic zeolites sometimes called sodium aluminosilicate

Synthetic zeolites have complex structures and examples (with structural formulae) are: * Na₁₂Al₁₂Si₁₂O₄₈·27H₂O, zeolite A (Linde type A sodium form, NaA), used in laundry detergentsAlan Dyer, (1994),''Encyclopedia of Inorganic Chemistry'', ed R. Bruce King, John Wiley & Sons, * Na₁₆Al₁₆Si₃₂O₉₆·16H₂O, Analcime, IUPAC code ANA * Na₁₂Al₁₂Si₁₂O₄₈·q H₂O, Losod"Formation and Properties of Losod, a New Sodium Zeolite", Werner Sieber, Walter M. Meie ''Helvetica Chimica Acta'', Volume 57 Issue 6, pp. 1533–1549, 10.1002/hlca.19740570608 * Na₃₈₄Al₃₈₄Si₃₈₄O₁₅₃₆·518H₂O, Linde type N

References

{{reflist Inorganic compounds Sodium compounds Aluminosilicates Zeolites Food additives E-number additives