Nomenclature
CAS number: 1344-95-2
Description and references
Many different forms of calcium silicate are
known. Among the most common forms are CaSiO3, Ca2SiO4 and Ca3SiO5. Usually
occur in hydrated form contg various percentages of water of crystallization.
Names of calcium silicate minerals are: afwillite; akermanite; calcium pectolith; centrallasite; crestmoreite; eaklite; foshagite; foshallasite; gjellebaekite; grammite; gyrolite; hillebrandite; larnite; okenite; parawollastonite; pseudo-wollastonite; riversideite; table spate; tobermorite; wollastonite; xonaltite; xonotlite. Commercial calcium silicate sold for industrial use,
such as Micro-Cell and Silene, is prepared synthetically to control its absorbing power.
The usual method of prepn is from lime and diatomaceous earth under
carefully controlled conditions: Boss, Chem.
Eng. News 27, 677 (1949); Steinour, Chem. Rev. 40, 391 (1947). The
commercial product is described here.
Properties
White or slightly cream-colored, free-flowing
powder. Approximate analysis: CaO 19%, SiO2 67%, H2O 6 to 8%. d25 2.10. Bulk density: 15-16 lb/cu ft. Absorbs 1 to 2.5 times its weight of
liquids and still remains a free-flowing powder. Total absorption
power for water about 600%, for mineral oil about 500%. Available
surface area: 95 to 175 m2/g. Ultimate particle size:
0.02 to 0.07 μ. pH of aq slurry 8.0 to 10.0. Practically insol
in water. Forms a siliceous gel with mineral acids.Caution
Potential symptoms of overexposure
are irritation of eyes, skin, upper respiratory system. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 48.Use
Constituent (produced
in situ) of lime
glass, portland cement; reinforcing filler in elastomers and plastics;
absorbent for liquids, gases, vapors; as anti-caking agent, suspension
agent, pigment and pigment extender; binder for refractory material;
in chromatography; in road construction.