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In this video we are going to make some
silicon. So I am weighing out 10 grams
of sand
with 8 grams of magnesium powder.
Then mix them together very very thoroughly
This is a thermite reaction
So what I have here is some concentrated hydrochloric acid
This will dissolve away any unreacted material
and any
by products, such as magnesium silicide
Here we are after the reaction mixture
has finished bubbling
Although it does appear to be bubbling
that's because I added some more concentrated
acid just to make sure I had removed all of the impurities
however it does not actually remove any
sand that
may be present
So the final product will be mostly
silicon with a small proportion of sand
So here we have the final product
and it's pretty pure
amorphous silicon which is why it does not look
as silvery and crystalline as in the pictures. It's fairly
coarse powder
which, if you wanted to use it as such,
a very good abrasive
in a later video, I may purify this by reacting it with bromine to form silicon tetrabromide, and then
and then decomposing that to form
pure silicon. This step will remove any residual impurities.