Sodium aluminate is an inorganic chemical that is used as an effective source of aluminium hydroxide for many industrial and technical applications. 

Pure sodium aluminate (anhydrous) is a white crystalline solid having a formula variously given as NaAlO2, NaAl(OH)4 (hydrated),[2] Na2O·Al2O3, or Na2Al2O4. 

Commercial sodium aluminate is available as a solution or a solid.

Other related compounds, sometimes called sodium aluminate, prepared by reaction of Na2O and Al2O3 are Na5AlO4 which contains discrete AlO45− anions, Na7Al3O8 and Na17Al5O16 which contain complex polymeric anions, and NaAl11O17, once mistakenly believed to be β-alumina, a phase of aluminium oxide.

olves neutralizing gluconic acid with a sodium base or by acidifying calcium gluconate with sulfuric acid, filtering the product and neutralizing the result with a sodium base. 

Other methods involve continuous neutralization of gluconic acid formed during submerged culture fermentation.

Structure

Anhydrous sodium aluminate, NaAlO2, contains a three-dimensional framework of corner linked AlO4 tetrahedra. 

The hydrated form NaAlO2·5/4H2O has layers of AlO4 tetrahedra joined into rings and the layers are held together by sodium ions and water molecules that hydrogen bond to O atoms in the AlO4 tetrahedra.

Sodium aluminate was introduced to the paper industry over 40 years ago. Its acceptance as an excellent wet end additive grew extensively in Europe and the U.S. paper making operations. Sodium aluminate was found to be very effective when used in conjunction with other cationic sources, such as alum, to optimize and improve wet end paper machine operations.

Simply stated, sodium aluminate is an alkaline form of aluminum which has been dissolved in caustic. Aluminum, because of its amphoteric nature, can be easily dissolved either in an acid or alkaline medium. Aluminum dissolved in sulfuric acid forms aluminum sulfate, or alum, and aluminum dissolved in caustic forms sodium aluminate. Sodium aluminate possesses an anionically charged alumina particle.

Sodium aluminate performs two basic functions in the paper maker process. One of these is primarily a chemical function which is to furnish a portion of the alumina required for sizing. Second function is best considered a physical function of coagulation and retention. System conditions created by these two reactions and the reaction products are the basis for the benefits provided by sodium aluminate.

Other benefits from sodium aluminate usage are:

Improved strength and durability

Cleaner machine system

Reduced foam

Reduced corrosion

Manufacturing

Sodium aluminate is manufactured by the dissolution of aluminium hydroxide (Al(OH)3) in a caustic soda (NaOH) solution. 

Aluminium hydroxide (gibbsite) can be dissolved in 20–25% aqueous NaOH solution at a temperature near the boiling point. 

The use of more concentrated NaOH solutions leads to a semi-solid product. The process must be carried out in steam-heated vessels of nickel or steel, and the aluminium hydroxide should be boiled with approximately 50% aqueous caustic soda until a pulp forms. 

The final mixture has to be poured into a tank and cooled; a solid mass containing about 70% NaAlO2 then forms. 

After being crushed, this product is dehydrated in a rotary oven. The resulting product contains 90% NaAlO2 and 1% water, together with 1% free NaOH.

Uses

In water treatment it is used as an adjunct to water softening systems, as a coagulant aid to improve flocculation, and for removing dissolved silica and phosphates.

In construction technology, sodium aluminate is employed to accelerate the solidification of concrete, mainly when working during frost.

Sodium aluminate is also used in the paper industry, for fire brick production, alumina production and so forth.

Sodium aluminate solutions are intermediates in the production of zeolites.

Other names: Sodium aluminium oxide; Sodium metaaluminate;  Aluminate, ((AlO2)1−), sodium

Identifiers: CAS Number: 1302-42-7 

Chemical formula: NaAlO2

Molar mass: 81.97 g/mol

Appearance: white powder (sometimes light-yellowish)

hygroscopic/ when dissolved in water a colloidal black solution is formed

Odor: odorless

Density: 1.5 g/cm3

Melting point: 1,650 °C (3,000 °F; 1,920 K)

Solubility in water: highly soluble

Solubility: Insoluble in alcohol[1]

Refractive index (nD): 1.566

SODIUM ALUMINATE

Sodium aluminum oxide

beta-Alumina

ALUMINUM SODIUM OXIDE

Dynaflock L

Monofrax H

Alumina-C

Sodium polyaluminate

Maxifloc 8010

Nalco 680

11138-49-1

VSA 45

Aluminium sodium dioxide

Sodium aluminate solution

EINECS 234-391-6

UN1819

UN2812

J 242

Torganit

Sodium metaaluminate

Sodium aluminum oxide (NaAlO2)

Aluminate, sodium

AlO2.Na

Sodium aluminum dioxide

Sodium aluminate, solid

Sodium aluminate, solution

EC 234-391-6

Sodium aluminate (NaAlO2)

Sodium aluminate (Na2Al2O4)

Sodium metaaluminate (NaAlO2)

DTXSID3051206

HSDB 5023

Aluminum sodium oxide (Al2Na2O4)