Q) complete the following statements using every given option.
During the extraction of aluminum....................
a. Ingredients and gangue in bauxite.
Answers
Answer:
Aluminium extraction is a chemical process that has several modifications in it. They are explained below.
Explanation:
Bauxite is the primary ore of aluminium.
Chemical formula of bauxite is Al2O3. xH20.
There are several impurities in bauxite.
The most found are silica or sand, titanium dioxide and iron oxides.
Aluminium oxide separation from the gangue is very difficult because of the silica that is mixed with it.
So chemical process like Hall's process is involved in getting pure aluminium oxide from the ore.
Here in Hall's process, bauxite ore is reacted with sodium carbonate .
Alumina being amphoteric in nature, reacts with both acid and base.
Alumina reacts with sodium carbonate to form sodium aluminate and water.
Al2O3 + Na2CO3 => NaAlO2 +H2O + CO2.
The the soluble sodium aluminate is filtered off from the slag.
Then it's precipitated in form of aluminium hydroxide.
NaAlO2 +CO2 +H2O => Al(OH)3 +Na2CO3.
Then aluminum hydroxide can be heated to form alumina
Al(OH)3 = Al2O3 + H2O.
Aluminium oxide is amphoteric in nature.
So it reacts with sodium hydroxide to form sodium aluminate and water.
Al2O3 + NaOH => NaAlO2 +H2O.