Exfoliated vermiculite is used in building boards to:
Boards containing exfoliated vermiculite are often used as a “core” in firedoors, to build fire barriers and to encase or construct fire resistant duct work, and to protect load supporting steel building elements from the effects of fire.
Binders used in these board systems include hydraulic binders such as Portland cement, calcium silicate and hemi-hydrate gypsum. There is also extensive use of alkali silicate solutions such as “water-glass,” which includes the more refractory potassium silicates as well as the regular sodium silicates. Other materials used as a binder for vermiculite in construction boards include organic resins and other propriety inorganic cements and bonding agents.