Page 22 - Curriculum Visions Dynamic Book

Refining iron ore: a small-scale
demonstration
Iron oxide will not react at room temperature. This is why a piece of iron oxide rock will simply sit on your window ledge for ever.
In common with many chemical reactions, you need to put in a lot of heat energy to make iron oxide react with other chemicals.
In the demonstration shown on this page, the principle of generating heat by chemical reactions is shown.
The apparatus
A container (in this case a plant pot with a hole in
the bottom, because it is cheap and it only melts at very high temperatures) is filled with a mixture of aluminium powder and iron oxide (iron ore) powder. A small cup-shaped indentation is made in the top of the mixture and some barium peroxide powder is added. A fuse of magnesium ribbon is buried in the top of the mixture.
 The magnesium ribbon fuse is lighted. Also...
This demonstration shows that
materials can be made to react at high temperatures even if they are completely unreactive at low temperatures. A modified form of this demonstration is used to weld rails as they are laid. A bag filled with the powder is tied around the rail sections to be welded and the fuse lit. The rest happens automatically!
The demonstration also shows the principle of extracting iron from its ore.
It requires a chemical reaction to strip the oxygen from the iron. However, the use of the equipment shown here is not practical for industrial purposes. Instead, charcoal or coke is used, as shown on pages 24 and 25.
Magnesium ribbon burns with an intense heat when lighted and so makes a good fuse.
Mixture of aluminium and iron oxide. At room temperature this mixture is completely unreactive.
Earthenware plant pot
 This unpromising earthenware plant pot contains the ingredients for a spectacular chemical reaction.
WARNING
This demonstration produces materials
with a temperature of 2000°C and must never be attempted by anyone except a qualified chemist.
Barium peroxide contains a
good supply of oxygen to help the magnesium release heat.
EQUATION: Chemical reduction of iron oxide to iron
Iron oxide + aluminium ➪ iron metal + aluminium oxide Fe2O3(s) + 2Al(s) ➪ 2Fe(s) + Al2O3(s)
22