Calcium silicate

Calcium silicate
IUPAC name	Calcium silicate
Other names	Calcium orthosilicate, silicic acid calcium salt, grammite, silene, micro-cell, belite
Identifiers
CAS number	1344-95-2 Y
PubChem	26370
SMILES	[Ca+2].[O-][Si]([O-])=O
InChI	1/Ca.O3Si/c;1-4(2)3/q+2;-2
InChI key	OYACROKNLOSFPA-UHFFFAOYAE
ChemSpider ID	24568
Properties
Molecular formula	Ca2SiO4
Molar mass	116.16 g/mol
Appearance	White or cream powder
Melting point	1540 °C, 1813 K, 2804 °F
Hazards
MSDS	[1]
Main hazards	Irritant
NFPA 704	0 2 0
Flash point	Not applicable
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Calcium silicate is the chemical compound Ca₂SiO₄, also known as calcium orthosilicate and sometimes formulated 2CaO.SiO₂. It is one of group of compounds obtained by reacting calcium oxide and silica in various ratios^[1] e.g. 3CaO.SiO₂, Ca₃SiO₅; 2CaO.SiO₂, Ca₂SiO₄; 3CaO.2SiO₂, Ca₃Si₂O₇ and CaO.SiO₂, CaSiO₃. Calcium orthosilicate is a white powder with a low bulk density and high physical water absorption. It is used as an anti-caking agent and an antacid. A white free-flowing powder derived from limestone and diatomaceous earth, calcium silicate has no known adverse effects to health^{[citation needed]}. It is used in roads, insulation, bricks, roof tiles, table salt^[2] and occurs in cements, where it is known as belite (or in cement chemist notation C₂S).

High temperature insulation

Industrial grade piping and equipment insulation is often fabricated from calcium silicate. Its fabrication is a routine part of the curriculum for insulation apprentices. Calcium silicate competes in these realms against rockwool as well as proprietary insulation solids, such as perlite mixture and vermiculite bonded with sodium silicate.

Passive fire protection

Circuit integrity fireproofing of cable trays in Lingen/Ems, Germany using calcium silicate board system qualified to DIN 4102. Other methods for exterior protection of electrical circuits include boards made of sodium silicate bonded and pressed vermiculite and flexible wraps made of ceramic fibre and rockwool.

One of the most successful materials in fireproofing in Europe is calcium silicate. Where North Americans use spray fireproofing plasters, Europeans are more likely to use cladding made of calcium silicate. Calcium silicate is easily damaged by water. Therefore, silicone treated sheets are available to fabricators to mitigate potential harm from high humidity or general presence of water. Fabricators and installers of calcium silicate in passive fire protection often also install firestops.

Calcium silicate in the steel industry

It is also a constituent of the slag that is produced when molten iron is made from iron ore and calcium carbonate in a blast furnace.

As a product of sealants

When sodium silicate is applied as a sealant to cured concrete or the shells of fresh eggs, it chemically reacts with calcium hydroxide or carbonate to form calcium silicate hydrate, sealing pores with a relatively impermeable material.

References

1. ^ H F W Taylor, Cement Chemistry, Academic Press, 1990, ISBN 0-12-683900-X, p 33-34
2. ^ http://www.mortonsalt.com/faqs/food_salt_faq.html#q6

See also

• Alite
• Belite
• Jaffeite
• Fireproofing
• Firestop
• Passive fire protection
• Plaster
• Perlite
• Sodium silicate
• Vermiculite