What is CaSi?
Calcium silicide (CaSi2), also called calcium disilicide, is an inorganic compound, a silicide of calcium. It is a whitish or dark grey to black solid matter with melting point between 700-935°C. It is insoluble in water, but may decompose when subjected to moisture, evolving hydrogen and producing calcium hydroxide. It decomposes in hot water. It is flammable and may ignite spontaneously in air.
There is a standard analytical methods for the identification of CaSi alloys: DIN 17580.
Calcium silicide is nominally of composition CaSi2, with small amounts of primary and secondary eutectically precipitated silicon.
The specifications for standard-grade commercial CaSi are summarized hereunder.
A number of multicomponent CaSi-based alloys contain up to 30 % aluminium, manganese, barium titanium, magnesium, mischmetal or iron. Those special CaSi-alloys are produced by a combination of carbothermic ore reduction followed by direct alloying.
Note: They are considered for the implementation of REACH as special preparations of CaSi and the additional metal.
CaSi has been registered on its own for REACH in 2010
the position paper of the CaSi Institute can be found under Position Papers section