Pat Hi Everyone,
Interesting. According to Ferroglobe web site, their photovoltaic solar-grade silicon metal (SgSi) is 99.999% purity or 5N. And, like the other processes that make SgSi, starts with the purification of metallurgical silicon metal (MgSi). To make MgSi, producers require quartz of 99.5% SiO2.
Our PUREVAP has made +4N Si using 98% SiO2. Tests to refine the process for higher purity are ongoing.
Regards
Patrick