Boron in Other Applications

A MULTITUDE OF USES

Boron truly is an integral part of modern life. Aside from its numerous primary applications—as a component in borosilicate glass, textile fiberglass, agriculture, wood protection, industrial processes, detergents, metallurgy, insulation, energy production, adhesives, and ceramics—boron and borates are used to:

Gypsum board

Gypsum board is widely used for internal walls and ceilings. As part of its manufacture, Optibor® boric acid can:

  • Increase strength
  • Reduce weight by about 10%
  • Provide better adhesion of the paper backing
  • Reduce curing time
  • Prevent wrinkle formation on the surface
  • Create a hard gypsum edge that withstands nailing and handling
  • Enhance fire retardancy

Adding Optibor to the gypsum slurry promotes the formulation of large bulky crystals (as opposed to long needle-like ones). These crystals impart a more rigid character, strengthening the board and providing a harder outer edge. They also result in faster drying times.

When also used in the starch adhesive that is used to reinforce the bond between wallboard’s paper backing and gypsum core, Optibor provides increased viscosity, quicker tack, and better fluid properties—all essential for the dependable adhesion of the paper to the core. Optibor also reacts with sodium (found in many gypsum deposits), preventing the sodium from creating wrinkles in the paper backing as the wallboard dries.

Optibor’s fire-retardant properties help prevent the paper backing from burning while in the oven and helps to protect the final product by inhibiting combustion and suppressing afterglow and smolder. And Optibor helps minimize issues that can result from the injection of foam into the slurry (as part of density and weight reduction processes).

Wire drawing

To make wire, metal rods are drawn through dies of successively decreasing diameter. Lubricant is necessary to reduce the friction between the rod and the dies. Because the lubricant—a drawing soap or grease—does not adhere well to the rod, a lubricant carrier is necessary. The carrier must form a tenacious coating on the rod, to which the lubricant will readily adhere. Either Neobor® or borax decahydrate can be used as an effective lubricant carrier—and can also be used to neutralize residual acid (from the removal of oxides prior to adding the lubricant) and prevent corrosion during storage. Throughout the cleaning, coating, baking, and drawing processes, these borates provide:

  • Ease of solubility in hot water
  • Dust-free operation
  • Long borate bath life and decreased need for agitation
  • Compatibility with electric resistance heat units
  • Easy air drying
  • Compatibility with calcium and sodium soaps
  • Longer life than can be achieved with lime
  • Superior performance on high carbon steel (eg, spring steel)
  • Enhanced phosphate coatings
  • Ease of removal from the rod or wire, if desired

Automotive

Borates are used in the manufacture or composition of numerous automotive parts. For more information about the use of borates in individual automotive components and processes, view:

Borates in automotive industry

Water

Industrial treatment processes

Semi-permeable membranes used in wastewater treatment are cleaned with a solution of sodium perborate tetrahydrate and EDTA, which gives better results than acid washing. In heat-exchange devices, corrosion of metals or alloys can be combatted through the use of borates, which in the presence of oxygen promote the formation of a passivating layer (ferric oxide film) that prevents further oxidation.

For more information about the use of borates in water-treatment chemicals, see Borates in Industrial Fluids and Lubricants.
 

Swimming pools

Borates’ greatest asset in swimming pools is their multi-functionality. They can:

  • Improve swimmer comfort—may reduce red eye and skin irritation when compared to chlorine
  • Soften water
  • Reduce scaling
  • Improve water clarity
  • Improve oxidizer performance and longevity (typically chlorine)
  • Provide exceptional buffering capacity
  • Reduce corrosion
  • Save energy
  • Be added easily and dissolve instantly

Borates provide both chemical and aesthetic benefits to the pool as well as potentially increase the longevity of pool plaster and other equipment. Unlike most other pool and water additives, borate are permanent and do not degrade or evaporate from the pool water with time. A single dose application will only need very minor top up, perhaps once a year, depending on how much has been removed by rainwater influx or back washing.

Autocausticizing

Patented Partial Borate Autocausticizing (PBAC) technology is implemented in pulp mills to supplement conventional lime causticizing, with little or no capital investment. These mills typically use PBAC to:

  • Reduce fresh lime consumption and lime mud disposal
  • Reduce fresh lime or caustic purchases
  • Increase white liquor/pulp production
  • Off-load lime kiln (energy/maintenance savings)
  • De-bottleneck causticizing circuits

PBAC uses Neobor® to react with sodium carbonate in the kraft pulping furnace to form intermediate borates. Once the reacted salts are dissolved in the green-liquor dissolving tank, sodium hydroxide is formed, and the intermediate borates are regenerated.

Blog: Borates for Autocausticizing in Paper Production

Refractories

Ammonium pentaborate can be used in gunning and patching compounds, to extend the life of basic refractories in steel furnaces. 20 Mule Team® Borax boric oxide is used in the manufacture of chemically bonded firebricks—as a binder for magnesia-based bricks and as a stabilizer for dolomite bricks (commonly used in steel smelting furnaces)—and castables, which require resistance to high temperatures, abrasion, and corrosion. Boric oxide is also an excellent solvent for metallic oxides at high temperatures. Dehybor® anhydrous borax and Neobor® are also used as stabilizers and bonding agents in firebricks and castables.

U.S. Borax is a proud member of:

 
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Leather manufacturing

Both borax decahydrate and Optibor® have been used in the leather industry since the latter half of the 19th century. The mild alkalinity of borax decahydrate and weak acidity of Optibor make them suitable for soaking hides and skins, stripping vegetable tans, and neutralizing chrome tans and limed pelts.

Nylon carpet dyeing

Aqueous borax decahydrate and Neobor solutions are known to exhibit relatively stable pH values at various concentrations and temperatures. For this reason, borax decahydrate is an excellent buffer and is recommended for pH control in the dyeing of nylon carpeting. The product offers the following advantages:

  • Reduction of monitoring and periodic bath adjustments
  • Better shade matching
  • Prevention of staining by jute backing

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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