Sodium aluminate

Sodium aluminate is an inorganic compound with the chemical formula NaAlO2. It is a widely used source of aluminium hydroxide in technical applications and as a coagulant in water treatment.

Chemistry

Sodium aluminate is a strong alkali. In water treatment, it is used as a source of alkalinity, which can be beneficial for treating acidic or low-alkalinity waters. It is also used in the Bayer process of aluminium production.

Production

Sodium aluminate can be prepared by treating aluminium oxide with sodium hydroxide. This reaction produces sodium aluminate and water:

2 Al2O3 + 2 NaOH → 2 NaAlO2 + H2O

Applications

Sodium aluminate is used in a variety of industrial applications. It is an important component in the production of aluminium, where it is used in the Bayer process to dissolve bauxite ore. It is also used in water treatment as a coagulant to remove suspended solids and organic matter.

In the construction industry, sodium aluminate is used as an accelerator for concrete. It reacts with the calcium hydroxide in cement to form calcium aluminate, which speeds up the setting time of the concrete.

Safety

Sodium aluminate is a strong alkali and can cause burns if it comes into contact with skin or eyes. It should be handled with care, using appropriate personal protective equipment.

See also

• Aluminium oxide
• Sodium hydroxide
• Bayer process
• Water treatment