Hello - Another possibility is smelting lead from galena in a 'bole
furnace' - essentially just an open bonfire. Here is what Tylecote
says about the procedure in his History of Metallurgy, 1976, p. 97:
'Only lead responds to such a primitive technique owing to the
relative ease of the double decomposition reaction, in which
partially oxidized lead (PbO) reacts with the unoxidized galena (PbS)
lower down to give metallic lead and sulphur dioxide. The yield is
poor, a good deal of the lead going into the slag. But as a way of
getting metallic lead easily and cheaply there is nothing to beat it.
Almost any sort of dry fuel can be used such as peat, coal, and wood,
and the rich slags can be reworked in a bellows blown 'slag hearth'.
These furnaces were usually situated on hill tops, not because of the
better draught - like any bonfire they will create their own - but
because the fumes spoilt the vegetation for miles around and the lead
deposits poisoned the soil.'
According to my notes there is more on this method in John Percy's
Metallurgy, vol. 3: Lead (1870, pp. 213ff). But I don't have this
handy and don't remember what it says.
I have been told that Tylecote's description of the chemistry of this
process is over-simplified, but that could be an interesting problem
for you to take up with your class.
For a more ambitious smelting project, consider some of the
traditional Chinese iron-smelting techniques described in my 'The
traditional Chinese iron industry and its modern fate' (Curzon Press,
1997), web version at http://staff.hum.ku.dk/dbwagner/Fate/Fate.html .
Regards,
Don Wagner
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lektor dr.phil. Donald B. Wagner
Asien-instituttet / Department of Asian Studies, University of Copenhagen
Leifsgade 33, DK-2300 Copenhagen S, Denmark
tel. +45-3532 8825 fax. +45-3532 8835
http://staff.hum.ku.dk/dbwagner
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