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Borax

Borax finds application in a variety of household laundry and cleaning products, as well as certain tooth cleaning formulations. It is also employed as an ingredient in glass and pottery glazes within the ceramics industry. In metallurgy, it serves as a solvent for metal-oxide slags, while in welding and soldering, it acts as a flux. Additionally, borax is utilized as an additive in fertilizers, a component in mouthwash solutions, and a water softener.

Synonyms
Sodium Borate, Sodium tetraborate, Disodium tetraborate, E285
Chemical Formula
Na2B4O7.xH2O
CAS Number
1330-43-4 (anhydrous), 1303-96-4 (decahydrate), 12179-04-3 (pentahydrate)

Characteristics

Molar Weight
381.38 g/mol (decahydrate)
Melting Point
75°C (decahydrate), 742°C (anhydrous)
Boiling Point
1575°C (anhydrous, decomposes)
Density
1.72 g/cm³ (decahydrate), 1.815 g/cm³ (pentahydrate)
Forms
Powder, White, Solid

Uses and Applications

Key applications

  • Buffer agent
  • Disinfectant
  • Welding
  • Food additive
  • Agricultural
  • Pharmaceuticals
  • Personal care

Industries

General information

Borax is a rare mineral from the mineral class of borates. The sodium salt of boric acid is also called sodium borate, boric acid soda or - rarely used nowadays - also tinkal. It is also known by its chemical name disodium tetraborate decahydrate.
Borax is produced annually worldwide in the megaton range. It is extracted from the borax mineral kernite by dissolving it in hot water. Pure borax is then produced by crystallisation. The natural form for borax is crystalline or massive - similar to anhydrite or gypsum as evaporite. Borax is formed, among other things, when salt lakes dry up, which are then called "borax lakes". The mineral is also found as soil efflorescence in arid regions, as sinter deposits at thermal springs or in volcanic vents. Known occurrences are in California, Argentina, Bolivia, Mexico, China, India and Italy, as well as in Turkey and the Ukraine.

Properties of borax

Borax belongs to the group of tetraborates. It crystallises in the monoclinic crystal system and is colourless and transparent in its pure form. Borax belongs to the so-called soft minerals, which can be deformed by mechanical means. For example, borax can be scratched with a fingernail. It dissolves in water and glycerine. When heated to about 100°C, it loses part of its crystallisation water and forms a pentahydrate. If the temperature is raised to 400°C, anhydrous sodium tetraborate is obtained, which melts at 742°C.
Hand on be bound with cement , do cement work, apply cement (over a surface)

Borax in industry and construction

Borax is used as a raw material for the production of boric acid, for the extraction of borates and perborates as well as other boron compounds. These are used in the glass and ceramics industries, among others. Borax is used in anhydrous form in the production of borosilicate glass and in enamel production. It is also an additive for light-fusing glazes on earthenware, ceramics, porcelain and glass.
Based on its oxide-dissolving effect, borax is also used as a flux in the soldering of precious metals as well as in fire welding and forging. In the construction sector, borax is used as an additive in cement and insulating materials. Furthermore, borax is used as a preventive wood preservative against mould, fungi and insects (insecticide), and as a flame retardant for cellulose-based insulating materials.
Female chemist writing formula on a glass wall, Allentown, USA

Borax in chemistry

Borax is used in chemistry as a means of detecting cations in the cation separation process as well as methanol. The mineral is also used for buffer solutions and as a dye in microscopy.
Window of delicious desserts at a pastry shop - food concepts

Borax in the food industry

Borax is only permitted within the food industry in the European Union as an additive for real caviar. In this case, it bears the designation E 285. Borax is used (sometimes, not always) in caviar production as a preservative and flavour enhancer. It helps to make the caviar last longer and can also improve the texture and taste. Borax softens the "fishy" taste and enhances the flavour of the caviar. This makes caviar more enjoyable for many people.

Other uses of borax

In agriculture, borax is also used as an ingredient for fertilisers (artificial fertilisers), because the trace element boron is an essential element for plant growth and plant nutrition. Too little boron can lead to a variety of symptoms, such as stunted growth, dead plant parts or reduced fertility. As an ingredient in detergents and disinfectants, it is often used as a bleaching agent.
In the textile industry, borax is used to make fibres and textiles more durable or fireproof. In the field of water treatment, borax helps to reduce water hardness in industrial processes, while in pool maintenance it is used to regulate the pH value and combat algae in swimming pools.
Furthermore, boron compounds are used in the production of batteries, for example in lithium-ion batteries used in electric cars. The reason here is improved conductivity.