metalresearcher - 7-10-2018 at 11:55
Freeing elemental Si from SiO2 is not possible by just silica sand (SiO2) and aluminum powder, as the reaction is not sustainable.
Many YouTube videos show making elemntal Si by adding some Sulfur and extra Al powder, mostly in 12 parts S, 10 parts Al and 9 parts SiO2. I tried it
out, it works (but slowly) and after cooling it yields a few chunks of elemental Si in the frozen puddle. But it has a horrible SO2 stench and after
cooling down an it had even more "Horrible To Stink" (H2S) gas due to Al2S3 reacting with water.
Then I tried a 'sulfurless' mixture to avoid the foul smelling gases:
10 parts SiO2, 8 parts Al and 3 parts KClO3.
This reacts more quickly and a very hot (> 1400 C) liquid results and after cooling down, I broke up the frozen puddle, there was not a larger
chunk, but I could see some small particles of lustrous black stuff which should be elemental Si. Now I let dissolve the impurities in dilute HCl
acid.
What are your experiences ?
12thealchemist - 7-10-2018 at 12:10
My YouTube video on making silicon: www.youtube.com/watch?v=OdV-yhaAbZc&t=61s
(most efficient way of answering in detail - a picture speaks a thousand words)
[Edited on 7-10-2018 by 12thealchemist]