Silicon Metal

All silicon metal shares a common origin:  Quartz (SiO2). Quartz is reduced to silicon (Si) in a high temperature melting process using carbon and high temperatures in an electric arc furnace.

For silicon metal to be used in solar and semiconductor applications it must be extremely pure.  For solar applications, the metal must be 99.9999% Si, while semiconductor applications require 99.999999999% purity.  No quartz product can be purified above 99.999% SiO2, which means silicon metal must go through successive purification processes before it can be used.

The most common method of silicon metal production is through a metallurgical process.  This process begins with a lump of quartz of medium to low purity mixed with carbon, which then goes through several cleaning steps to be processed into higher grades.  This silicon metal can then be used for silicon crystals, which are sliced and used as wafers for the semiconductor and solar industry.  Silicon metal processing often involves slag refining, which is made possible using high purity quartz.  For more information on slag refining and silicon metal production can be found here.  

 

To create silicon metal that is good enough for solar silicon, the silicon must be very clean, 99.9999%