Borates

Borate is the sodium substitute for potassium, and when it is high in sodium, it is called 'natroalunite.'

The History Says

Borates additional applications were discovered when, by 1830s, scientists understood the pharmaceutical uses of boric acid. The subsequent generation discovered enameling of iron, preserving meats, harden plaster, making glass heat resistant, and cleansing with borates.

The Present Scenario

Most of the borates in the world are supplied by Rio Tinto Borax from the southern United States. Death Valley in California is famous for borate mining. Atacama Desert in Chile also contain mineable borate concentrations.

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BORATE IS a compound of the borate ion with metallic elements. The boron found in nature is usually in the form of borate mineral. It is sometimes also combined with silicate and forms complex borosilicate minerals like tourmalines.

There are different forms of existence of borate. The acid condition is known as boric acid (H₃BO₃). The basic conditions occur like dihydrogen borate ion H₂BO_3-. The hydrogen borate ion is HBO₃^2- and borate ion is BO3^3-.

Borate forms many polymeric ions. The common is tetraborate ion, B₄O₇^2-. The hydrogen tetraborate ion is HB₄O₇^-. It also occurs as triborate and pentaborate. Various metaborate ions have an empirical formula of BO₂^- and forms metaborate compounds.

The usual borate salts include sodium metaborate (NaBO₂) and sodium tetraborate (Na₂B₄O₇). Sodium tetraborate even occur naturally as hydrous mineral borax (Na₂B₄O₇·10H₂O)

Principal Sedimentary Borate Minerals

Shallow lake deposits formed by precipitation and evaportion Boron (United States), Kirka (Turkey) and Tincalayu (South America)

Mineral	Formula	B2O3 content (wt%)
Primary Borax Ulexite	Na2O·2B2O3·10H2O Na2O·2CaO·5B2O3·16H2O	36.5 43.0
Secondary Kernite Ulexite Colemanite	Na2O·2B2O3·4H2O Na2O·2CaO·5B2O3·16H2O 2CaO·3B2O3·5H2O	51.0 43.0 50.8
Szaibelyite	Liaoning Province (China) 2MgO·B2O3·H2O	41.4

Formed by Precipitation from Cooling Hot-Spring Fluids Argentina and Death Valley (United States)

Mineral	Formula	B2O3 content (wt%)
Primary Ulexite	Na2O·2CaO·5B2O3·16H2O	43.0
Secondary Proberite Colemanite	Na2O·2CaO·5B2O3·10H2O 2CaO·3B2O3·5H2O	49.6 50.8

Source: American Ceramic Society Bulletin, Vol. 81, No. 8

Different Types of Borate

• Borate ion - BO₃^3-
• Boric acid - H₃BO₃
• Dihydrogen borate ion - H₂BO₃
• Hydrogen borate ion - HBO₃^2-
• Tetraborate ion - B₄O₇^2-
• Hydrogen tetraborate ion - HB₄O₇
• Sodium metaborate - NaBO₂
• Sodium tetraborate - Na₂B₄O₇
• Hydrous mineral borax - Na₂B₄O₇.10H₂O
• Trimethyl borate - B(OCH₃)₃

Common Borate Minerals

• Kernite - Na₂B₄O₇.4H₂O
• Borax - Na₂B₄O₇.10H₂O
• Ulexite - NaCaB₅O₉.8H₂O
• Colemanite - Ca₂B₅O₁₁.5H₂O

Main Sources of Borates

Most of the borates in the world are supplied by Rio Tinto Borax from the southern United States. The company was established by Francis Marion Smith in 1883 which was then known as The Harmony Borax Works. In 1872, Mr. Smith found borates in the Nevada desert.

Death Valley in California is famous for borate mining. Atacama Desert in Chile also contain mineable borate concentrations.

Uses of Borates

Borate's various forms are used as wood preservatives. Borate esters is used as a precursor to boronic esters for Suzuki couplings. It also includes trimethyl borate, B(OCH₃)₃.