11-02-2013, 02:59 PM
Preparation of Potash Alum
[attachment=50513]
Introduction
Aluminium because of its low density, high
tensile strength and resistance and resistance to corrosion
is widely used for the manufacture of aeroplanes,
automobiles lawn furniture as well as for aluminium cans.
Being good conductor of electricity it is used for
transmission of electricity. Aluminium is also used for
making utensils. The recycling of aluminium cans and
other aluminium products is a very positive contribution
to saving our natural resources. Most of the recycled
aluminium is melted and recast into other aluminium
metal products or used in the production of various
aluminium compounds, the most common of which are
the alums.
Procedure
Allow the filtrate to cool. Now add slowly 6 M
H2SO4 until insoluble Al(OH)3 just forms in the
solution.
Gently heat the mixture until the Al(OH)3
precipitate dissolves.
Cool the resulting solution in an ice-bath for about
30 minutes whereby alum crystals should separate
out. For better results the solution may be left
overnight for crystallization to continue.
In case crystals do not form the solution may be
further concentrated and cooled again.
Filter the crystals from the solution using vacuum
pump, wash the crystals with 50/50 ethanol-water
mixture.
[attachment=50513]
Introduction
Aluminium because of its low density, high
tensile strength and resistance and resistance to corrosion
is widely used for the manufacture of aeroplanes,
automobiles lawn furniture as well as for aluminium cans.
Being good conductor of electricity it is used for
transmission of electricity. Aluminium is also used for
making utensils. The recycling of aluminium cans and
other aluminium products is a very positive contribution
to saving our natural resources. Most of the recycled
aluminium is melted and recast into other aluminium
metal products or used in the production of various
aluminium compounds, the most common of which are
the alums.
Procedure
Allow the filtrate to cool. Now add slowly 6 M
H2SO4 until insoluble Al(OH)3 just forms in the
solution.
Gently heat the mixture until the Al(OH)3
precipitate dissolves.
Cool the resulting solution in an ice-bath for about
30 minutes whereby alum crystals should separate
out. For better results the solution may be left
overnight for crystallization to continue.
In case crystals do not form the solution may be
further concentrated and cooled again.
Filter the crystals from the solution using vacuum
pump, wash the crystals with 50/50 ethanol-water
mixture.