Excellent buffering capabilities
A superb buffering agent, 20 Mule Team® potassium tetraborate can lower the pH of strong alkalis and is also used in welding, soldering, and brazing fluxes.
Alkali borate without sodium salts
Potassium tetraborate results from the controlled reaction of potassium hydroxide, water, and boric acid. This alkaline salt has excellent buffering capacity and replaces borax where an alkali borate is needed but sodium salts cannot be used. Potassium tetraborate is also more soluble in water than borax.
Analytical procedures
When dissolved in water, potassium tetraborate hydrolyzes to produce a mildly alkaline solution that can neutralize acids. For example, the pH of a 2% (wt.) solution of potassium tetraborate is 9.2. This value increases slightly with increasing concentrations and diminishes slightly with increasing temperatures. The relatively constant pH of potassium tetraborate solutions makes them excellent buffering agents, often recommended as primary standards in analytical procedures and used in detergents, eye drops, and other applications.
Metallic oxide solvent
Potassium tetraborate is also an excellent solvent for metallic oxides at high temperatures.
Metallurgy
The product is used to prepare special welding, soldering, and brazing fluxes of stainless steel or other non-ferrous metals, where it helps prevent the glare that is associated with sodium borate.
Gear lubrication
Dispersed in a very finely divided state, potassium tetraborate improves the load-carrying, inhibits corrosion, and antiwear properties of industrial and automotive gear lubricants. Under extreme conditions, it interacts with metal load-bearing surfaces to form a film of extraordinary resilience. This tenacious film provides outstanding load-carrying capacity and wear protection.
Nuclear safety
As a highly pure form that can generate higher concentrations of boron—a good absorber of thermal neutrons—than other refined borates can, potassium tetraborate is used for emergency shutdowns in nuclear-powered ships.
And, more
Like 20 Mule Team potassium pentaborate, potassium tetraborate can be used to create alight-sensitive composition (diazotype developer).
Technical Details
Potassium tetraborate shows little tendency to cake except after prolonged storage or when severely wetted by rain or substantial water penetration. The product can also absorb moisture if exposed to a humid environment.
Heated in a vacuum, the crystal line salt begins to melt in its own water at about 100°C (212°F), losing two molecules of water. The anhydrous salt is formed at about 500°C (932°F) and fuses to a clear glass at 815°C (1500°F).
Aqueous solutions of potassium tetraborate show a slight decrease in pH, followed by a moderate increase in pH with increasing concentrations.
We're here to help with your boron needs.
Get technical support
Your resource for borate-related technical and laboratory services across every industry
Request a sample
Get small quantities of our products to ensure you have what you need for your formulation or process