Borax Decahydrate

Borax Decahydrate

A multifunctional source of boric oxide

From detergents to dyes to adhesives, this mild alkaline salt does it all, particularly excelling as a buffering and fluxing agent.
Borax and Detergents

Gentle Cleaning, Powerful Protection

20 Mule Team® borax decahydrate is the refined form of natural sodium borate. Composed of boric oxide (B2O3), sodium oxide, and water, this mild alkaline salt has excellent buffering and fluxing properties. Available in a white crystalline powder or granular form, borax decahydrate is an important multi-functional source of boric oxide, particularly for processes in which the simultaneous presence of sodium is beneficial.


Borax decahydrate is incorporated into many cleaning products as a pH buffering agent. It aids in the emulsification of oils and serves as a gentle abrasive. The product can be added to powdered hand soaps as an effective way to remove medium-to-heavy soils—such as those encountered in industrial operations—yet it is gentle to the skin. Borax decahydrate is often added to:

  • Formulations that are used to clean hard surfaces (eg, metals, glass, ceramics)
  • Polishes and waxes
  • Industrial institutional cleaning compounds

Laundry detergents

The product helps with the removal of oily soils from fabrics, and imparts alkalinity, pH buffering, and softening of the wash water. Plus, borax decahydrate can be used to stabilize enzymes.

Cosmetics, toiletries, and pharmaceuticals

In contact lens solutions, it is used with boric acid as a gentle cleanser and buffering agent. Borax decahydrate is also used as a cross linking agent to emulsify waxes and other paraffins that form the base for lotions, creams, and ointments.


Aside from its use as a cleaning agent, borax decahydrate is prized for its ability to dissolve metal oxides where it’s used in the recovery of metals such as brass, copper, lead, and zinc from scrap or smelting slag. In ferrous metallurgy, the product is used as a cover flux to prevent oxidation at the surface of the molten ingot. In welding, brazing, and soldering, borax decahydrate is used to cover the metal surfaces, where it excludes air and prevents oxidation.

Speaking of oxidation, borax decahydrate slows corrosion in aqueous systems, water treatment chemicals, and in the manufacture of automotive and engine coolant formulations. Aqueous solutions of borax decahydrate have replaced chromates in railroad and other diesel engine coolants. And, because borax decahydrate is highly soluble in ethylene glycol, it is especially useful in car antifreeze formulations. It neutralizes the acidic residue that results from the decomposition of ethylene glycol and minimizes the rate of oxidation at the surface of the metal.

In refractories, the borax decahydrate is used as a stabilizer and bonding agent in specialty abrasives. Borax decahydrate also provides an intermediate-temperature glassy bond before the establishment of the ceramic bond.


Borax decahydrate is also part of the starch adhesive formulation for corrugated paper and paperboard. It is a cross-linking agent in the manufacture of casein-and dextrin-based adhesives, and it greatly improves the tack and green strength of such adhesives by cross linking conjugated hydroxyl groups.

Wire drawing

Borax decahydrate neutralizes the residual acid from the pickling stage, and the deposit of the salt remaining on the wire is valuable as a carrier of dry powdered lubricant.

And, more

Borax decahydrate doesn’t stop there. It’s also used as a flame retardant for cellulosic materials, a buffer and catalyst for organic dyes, a carrier for herbicides, and a degreasing buffer in enameling processes.


Boric Oxide

Borax decahydrate is gentle enough to use in soaps, detergents, and personal care products.


Borax Decahydrate APPLICATIONS
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Borax decahydrate dissolves metal oxides for improved recovery of brass, copper, lead, and zinc.


Available Grades

Borax decahydrate TG has a No. 8 U.S. sieve specification, with a mesh size of 2.36 mm and a retained guarantee of 0.1% or less. These specifications, as well as the product’s chemical properties, are determined by U.S. Borax analytical methods.

Dissolved in water, borax decahydrate hydrolyzes, producing a mildly alkaline solution that can neutralize 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.

Borax decahydrate is chemically stable under normal storage conditions, although it will slowly lose water of crystallization if exposed to a warm, dry atmosphere. For borax decahydrate EP, NF, and SP grades we recommend NOT storing in a controlled atmosphere below 60% of relative humidity. Conversely, exposure to a humid atmosphere can cause caking. When storing the product, avoid wide fluctuations in temperature and humidity and ensure that the packaging is not damaged.

The product’s solubility in water; solubility in solvents such as glycerol, ethylene glycol, methanol, and acetone; and the product’s pH as compared to that of common alkalis can be found in the product data sheet.
Chemical and Physical Properties

Molecular weight: 381.37

Specific gravity: 1.71

Appearance: Free-flowing, white, crystalline product

Melting point: 743°C (1369°F), starts losing water at 62°C (144°F) in an enclosed space

Solubility: 5.93% by weight in saturated solution at room temperature

Stability: Chemically stable under normal conditions; avoid temperature and humidity fluctuations and prevent damage to packaging

Bulk density: 48 lb/ft3 (769 kg/m3)

Angle of repose: 35°

Chemical Composition (Theoretical)

Boric oxide, B2O3: 36.51%

Sodium oxide, Na2O: 16.25%

Water of crystallization, H2O: 47.24%

Anhydrous equivalent, NaBO2: 52.76%

Containers: Products may be available in bulk, IBCs, or small bags

Borax Decahydrate in Action

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U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 500 customers with more than 1,700 delivery locations globally. We supply 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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