Page 8 - Curriculum Visions Dynamic Book
P. 8
Refining lead in the laboratory
Lead ore normally occurs as an oxide or a
sulphide. On these pages you can see a laboratory demonstration of the principle of refining the ore. You can then compare this with the industrial processing shown on pages 10 and 11. In this demonstration an orange form of lead monoxide
(lead II oxide, PbO) is used, known as litharge.
To produce lead from its ore, the ore is first reduced (its oxygen removed) by placing it in
a hollowed-out carbon block. The hollowing
is important because the molten lead metal needs
to be contained as the demonstration progresses.
Lead has a low melting point, so this demonstration proceeds under the heat of an ordinary Bunsen flame.
Lead monoxide powder is heated on a carbon block.
The carbon block reduces some of the oxide and forms a molten globule of lead metal. Colourless carbon monoxide gas is given off during this reaction.
EQUATION: Reduction of lead monoxide
Lead monoxide + carbon ➪ lead + carbon monoxide 2PbO(s) + 2C(s) ➪ 2Pb(s) + 2CO(g)
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