Silicon Francisco Javier Cervigon Ruckauer

Silicon

PRODUCTION OF SILICON


























OCCURRENCE OF SILICON

As has been discussed during this learning sequence, silicon, although it is the second most abundant element in earth’s crust, never occurs in nature as a free element but always appears associated with oxygen in the form of silicon dioxide, SiO2or silica, and with oxygen and other metals to form which are known as silicates. The minerals containing silicon, which usually are referred to as siliceous minerals, are the most important class of minerals because they represent about a quarter of the total known minerals in earth and account for 90% of the mass of the earth’s crust.
Silicon dioxide is definitely the most important compound of silicon and occurs in nature in different crystalline forms and some non-crystalline combinations where quartz is the most important polymorph or modification of silica. α-Quartz is the only modification stable at surfaces temperatures and pressure, special temperature and pressure conditions being necessary to obtain the other polymorph, which would tend to transform into quartz when enough time is given.
The next table shows the main data about the mineral sources of silicon and its abundance on earth.

SILICA, SILICA GEL, AEROGEL, SILICATES, GLASSES AND SILICONES


























ALUMINOSILICATES: CLAYS, FELDSPAR, ZEOLITES AND CERAMICS


























Francisco Javier Cervigon Ruckauer

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