is there any chemical method to extract Silicon Dioxide from sand?

Question

Is SiO2 is being extracted on industrial level any where or its only a part of laboratory work. Does any body know about its price? please tell me!

Answer 1

The only method I know is basic extreme heat and cooling. If it's done right, the different elements will cool at different temperatures and separate naturally.
I don't know, that was just a fun guess. I see it all the time in the different layers of volcanic rock.

Answer 2

Extracting Silicon Dioxide from Sand :
Description of the method :
Magnesium and sand are heated together and silicon is produced by an exothermic reaction. The product is placed in acid to remove magnesium oxide and unreacted
magnesium. Small amounts of silanes are produced by the reaction of magnesium silicide (a side product) with the acid. These react spontaneously with air to give spectacular but harmless small explosions.
Apparatus

One pyrex test-tube, approximately 150 mm x 17 mm.

Clamp and stand.

Bunsen burner.

One 250 cm3 beaker.

One 250 cm3 conical flask.

Filter funnel and filter paper.

Access to oven.

Desiccator.

Access to top pan balance.

Safety screen.
Chemicals
The quantities given are for one demonstration.

1 g of dry magnesium powder.

1 g of dry silver sand.

About 50 cm3 of approximately 2 mol dm–3 hydrochloric acid.
Method
Before the demonstration
It is important that the reactants are dry. Dry the magnesium powder and the sand for a few hours in an oven at about 100 °C. Store them in the desiccator until ready to use them. Ensure that the test-tube is dry.
The demonstration :
-Weigh 1 g of silver sand and 1 g of magnesium powder and mix them thoroughly.
-This mixture has a small excess of magnesium over the stoichiometric masses (1 g of sand to 0.8 g of magnesium) because some magnesium will inevitably react with air.
Spread the mixture along the bottom of a test-tube that is clamped almost horizontally. Place a safety screen between the tube and the audience if the spectators are close.
Heat one end of the mixture with a roaring Bunsen flame, holding the burner by hand. After a few seconds the mixture will start to glow. This glow can be ‘chased’ along the tube with the flame until all the mixture has reacted. The tube will blacken and partly melt. If the two powders are not dry, some magnesium will react with the steam and the resulting hydrogen will pop. This can be disconcerting if it is not
expected.When the reaction is complete, allow the mixture to cool (about five minutes) and with the aid of a spatula pour the products into about 50 cm3 of 2 mol dm–3 hydrochloric acid to dissolve away unreacted magnesium and magnesium oxide. The solid will contain silicon, magnesium oxide (the main products), magnesium silicide
formed from the reaction of excess magnesium with silicon, unreacted magnesium and possibly a little unreacted sand. The mixture will fizz as excess magnesium reacts
with the acid. There will also be pops accompanied by small yellow flames. These are caused by silanes that are formed from the reaction of magnesium silicide with acid. Silanes inflame spontaneously in air. Magnesium oxide will dissolve in the acid. After a few minutes the pops will cease and grey silicon powder, possibly with a little unreacted sand, will be left on the bottom of the beaker. Pour off the acid, wash
the solid a few times with water and filter off the silicon. It can be passed around the class to show its slightly metallic silver-grey colour. If desired show that it does not react with alkalis (or acids).
Visual tips :
Make sure the safety screen is clean if one is used.

Theory
The reactions are:
SiO2(s) + 2Mg(s) → 2MgO(s) + Si(s)
2Mg(s) + Si(s) → Mg2Si(s)
MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O(l)
Mg2Si(s) + 4HCl(aq) → 2MgCl2(aq) + SiH4(g)
(Higher silanes such as Si2H6 may also be produced.)
SiH4 (g) + 2O2(g) → SiO2(s) + 2H2O(l)
.
Silicon is extracted from sand industrially by reduction with carbon.
Safety
Wear eye protection.
Use a safety screen between the apparatus and the audience.
Magnesium powder burns vigorously in air. The dust from magnesium powder may be hazardous. Ensure that the mixed powders are absolutely dry before the reaction.
It is the responsibility of teachers doing this demonstration to carry out an appropriate risk assessment.