3. Alum, from which the element aluminium
takes its name was known from very early
times. But a cheap method of extraction of
Aluminium could not be discovered for a very
long time . Aluminium was first isolated only
in 1885 when Oersted obtained it by reducing
Aluminium chloride with potassium. Then it
was costlier than gold.
4. The discovery of this modern metal has
made a great impact on industry and on our day to day
life. On account of its low density it is used in
construction work. The alloy of Aluminium and
Magnesium is still lighter and can be worked easily in a
lathe. Aluminium does not corrode easily in air. It is
not attacked by water. An alloy of Aluminium and
Magnesium even resists sea water. The metal is a good
conductor of heat and electricity. Alnico which is an
alloy of Aluminium is a very good magnetic substance.
These properties make the metal very useful.
5. To make Utensils
To make automobile parts
To make ice cube tray
To make roofs
To use in reflecting telescope
To obtain metals from Cr2O3 , Mn2O3
6. Good thermal conductivity
Can be used as thin sheets
Low weight
Does not easily undergo corrosion
Electrical conductivity and many
more!
7. There was a time when aluminium was costlier than
gold! In those days aluminium was extracted from clay. It
was a very complex and costly process. Through a series of
experimental activities the young scientist Martin Hall
developed a scientific and cost – effective method for
preparing aluminium. In the same period another scientist
Paul Heroult also developed a similar method for preparing
aluminium. Hence the preparation of aluminium is known
as Hall-Heroult process. Bauxite (Al2O3 2H2O) is the ore of
aluminium..
8. Name of Alloys components Important uses
Aluminium bronze Cu, Al For making coins, utensils, statues,
ornaments etc
Alnico A l, Ni, Co, Fe For making magnets
Duralumin Al, Cu, Mg, Mn Construction of aircrafts
Magnalium Al, Mg For making the super structure of
trawlers, steamers, etc
silumin Al, Si Casting engine parts
