|Other Name:||Sodium Borate||CAS NO:||1303-96-4|
|Molecular Weight:||381.37||HS CODE:||2840190000|
sodium tetraborate decahydrate,
sodium borate decahydrate
Borax, also known as sodium borate, sodium tetraborate, or disodium tetraborate,
is an important boron compound, a mineral, and a salt of boric acid. Powdered
borax is white, consisting of soft colorless crystals that dissolve easily in water. A
number of closely related minerals or chemical compounds that differ in their crystal
water content are referred to as borax, but the word is usually used to refer to the
decahydrate. Commercially sold borax is partially dehydrated.
Borax is a component of many detergents, cosmetics, and enamel glazes. It is
compound, in the manufacture of fiberglass, as a flux in metallurgy, neutron-
capture shields for radioactive sources, a texturing agent in cooking, as a precursor
for other boron compounds, and along with its inverse, boric acid, is useful as an
In artisanal gold mining, the borax method is sometimes used as a substitute for
toxic mercury in the gold extraction process. Borax was reportedly used by gold
miners in parts of the Philippines in the 1900s.
Borax was first discovered in dry lake beds in Tibet and was imported via the Silk
Road to the Arabian Peninsula in the 8th Century AD.Borax first came into common
use in the late 19th century when Francis Marion Smith's Pacific Coast Borax
Company began to market and popularize a large variety of applications .
The structure of the anion [B4O5(OH)4]2− in borax
The term borax is often used for a number of closely related minerals or chemical
compounds that differ in their crystal water content:
· anhydrous sodium tetraborate, Na2B4O7
· sodium tetraborate pentahydrate, Na2B4O7·5H2O
· setraborate decahydrate, Na2B4O7·10H2O
Borax is generally described as Na2B4O7·10H2O. However, it is better formulated
as Na2[B4O5(OH)4]·8H2O, since borax contains the [B4O5(OH)4]2− ion. In this
structure, there are two four-coordinate boron atoms (two BO4 tetrahedra) and two
three-coordinate boron atoms (two BO3 triangles).
Borax is also easily converted to boric acid and other borates, which have many
applications. Its reaction with hydrochloric acid to form boric acid is:
Na2B4O7·10H2O + 2 HCl → 4 H3BO3 + 2 NaCl + 5 H2O
The "decahydrate" is sufficiently stable to find use as a primary standard for acid
When borax is added to a flame, it produces a yellow green color.Borax is not used
for this purpose in fireworks due to the overwhelming yellow color of sodium. Boric
acid is used to color methanol flames a transparent green.
Borax Decahydrate is the refined form of natural sodium borate. Composed of boric
oxide (B2O3), sodium oxide, and water, it is a mild, alkaline salt, white and
crystalline, with excellent buffering and fluxing properties. Available in powder or
granular form, Borax Decahydrate is an important multifunctional source of B2O3,
particularly for processes in which the simultaneous presence of sodium is
|Properties||White power or crystal granular|
Specification for borax decahydrate powder 95%
1. Borax Decahydrate is chemically stable under normal storage conditions. It will
slowly lose water of crystallisation if exposed to a warm, dry atmosphere.
Conversely, exposure to a humid atmosphere can cause recrystallisation at particle
contact points, resulting in caking. When storing the product, care should therefore
be taken to avoid wide fluctuations in temperature and humidity, and to ensure that
the packaging is not damaged.
2. Dissolved in water, Borax Decahydrate hydrolyzes to give a mildly alkaline
solution. It is thus capable of neutralizing acids. It also combines with strong alkalis
to form compounds of lower pH. The relatively constant pH of Borax Decahydrate
solutions makes it an excellent buffering agent.
1. Metallurgical fluxes
The ability of Borax Decahydrate to dissolve metal oxides is exploited in the
recovery of metals such as brass, copper, lead and zinc from scrap or smelting
In ferrous metallurgy, Borax Decahydrate is used as a cover flux to prevent
oxidation at the surface of the molten ingot. In welding, brazing, and soldering,
Borax Decahydrate covers the metal surfaces, excluding air and preventing
oxidation. It also acts as a solvent and cleaning agent.
2. Corrosion inhibition
Borax Decahydrate is incorporated in many aqueous systems requiring corrosion
inhibition. It protects ferrous metals against oxidation and finds use in the
manufacture of automotive and engine coolant formulations, and various water
treatment chemicals.The high solubility of Borax Decahydrate in ethylene glycol
makes it especially useful in car antifreeze formulations. Borax Decahydrate
neutralizes the acidic residue resulting from the decomposition of ethylene glycol
and minimizes the rate of oxidation at the surface of the metal. Aqueous solutions
of Borax Decahydrate have replaced chromates in railroad and other diesel engine
Borax Decahydrate is part of the starch adhesive formulation for corrugated paper
and paperboard, and is a peptizing agent in the manufacture of casein-based and
dextrin-based adhesives. It greatly improves the tack and green strength of the
adhesive by crosslinking conjugated hydroxyl groups.
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