I need silicon for alloying with aluminum (most often around 10% Si content). Was thinking of reducing sand, but since carbon needs an arc furnace, and a thermite reaction won't work very well (all the products are about the same density, unlike iron or copper-bearing thermite where the product is dense and settles out), I was thinking of a more indirect method.
Combining sand with molten metal doesn't work because even if I could break the oxide layer between the grain of sand and the metal, it would immediately re-form (with the little silicon produced dissolving in the metal) and stop. A flux is needed, and salt seems to keep the oxide mobile (if not necessarily in solution). By mixing aluminum, salt and sand in a crucible and melting to around 1600°F, I've got reasonable results after a few minutes, but I don't know how well the reaction is going. I've tried to assay the metal, but the silicon superstructure is too tight and the aluminum dissolves slowly (with muriatic acid).
Tim
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