Dear Sir/Madam,
Will the following reaction take place:-
Silica sand + hydrogen --> silicon + steam
SiO2 + 2H2 --> Si + 2H2O
Will it be necessary to heat up the silica sand before passing the hydrogen through it ?

Senior Member Perito, answered:- Yes and the heating up should be well above 1000 degrees C. Thank you Sir !!!

Now one last further question ---- why will the above reaction take place AND NOT the following one:-

SiO2 + H2 --> SiO + H2O

Can this latter reaction be prevented ?

Thank you in anticipation
Lourens

The simple answer is "no". It can't be prevented. However, if you have a large excess of hydrogen, you will minimize the formation of SiO, and it can almost be eliminated.