EXTRACTION OF ALUMINIUM :
Aluminium is the most abundant element next to oxygen and silicon. It is the most abundant metal of about 7.2% on the earth's crust. It was first isolated by Wohler in 1827. It was obtained by the electrolysis of bauxite by Charles martin hall in 1886.
Occurrence :
Bauxite, Cryolite and Corundum are the three minerals of aluminium. Bauxite is the ore and is extracted by the purification and electrolytic reduction.
Purification by Bayer's process :
The bauxite ore is powered and digested with a solution of caustic soda at 150°C in an autoclave under high pressure. Finally as the end of the reaction pure alumina is produced.
Electrolytic reduction :
Molten alumina is dissolved in molten Cryolite in a cast iron tank lined with a layer of graphite. A bunch of graphite rods are suspended in the molten Cryolite is the anode. This reaction take place at 900-950°C. The oxygen gas evolved burns the graphite rods away.
Physical properties of aluminium :
Aluminium is a silvery white metal of light density (2.7gm/cm³).It is metal having high tensile strength and melting point of 660°C.
Uses of Aluminium :
Aluminium is used in making electric cables, utensils, airplane parts, silver paints, fireworks, flashlight powders and explosives.
Aluminium is the most abundant element next to oxygen and silicon. It is the most abundant metal of about 7.2% on the earth's crust. It was first isolated by Wohler in 1827. It was obtained by the electrolysis of bauxite by Charles martin hall in 1886.
Occurrence :
Bauxite, Cryolite and Corundum are the three minerals of aluminium. Bauxite is the ore and is extracted by the purification and electrolytic reduction.
Purification by Bayer's process :
The bauxite ore is powered and digested with a solution of caustic soda at 150°C in an autoclave under high pressure. Finally as the end of the reaction pure alumina is produced.
Electrolytic reduction :
Molten alumina is dissolved in molten Cryolite in a cast iron tank lined with a layer of graphite. A bunch of graphite rods are suspended in the molten Cryolite is the anode. This reaction take place at 900-950°C. The oxygen gas evolved burns the graphite rods away.
Physical properties of aluminium :
Aluminium is a silvery white metal of light density (2.7gm/cm³).It is metal having high tensile strength and melting point of 660°C.
Uses of Aluminium :
Aluminium is used in making electric cables, utensils, airplane parts, silver paints, fireworks, flashlight powders and explosives.