A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...

128 THE METALLURGY OF ANTIMONY.
sodium sulphide solution and then boiled repeatedly with water;
they are then allowed to pass through o into the filter p, where
they are washed again with hot water. The wash-waters collected
in the holder q are used again for washing other residues. Such a
plant can extract 6 to 8 cwts. of antimony from its ores containing
less than 10 per cent, of the metal in twelve hours.
Figs. 57 and 58 show the arrangement of the electrolytic baths on
a large scale. A are the anodes, K the cathodes, which are hung in
iron baths. The cathodes are of sheet-iron and bolted on to the
rails T, and rest directly upon the rim of the baths, so that the
baths also serve as cathodes. The anodes are plates of lead suspended
FIG. 58.
from iron rails, resting upon the positive leads, which are isolated by
resting on the wooden bars J. The electrolyte is fod through the
three-way cock D under the bath, since it becomes less dense as the
antimony is removed. The outlet is through G by means of the
rubber pipes S into the next bath. In order to effect an oven distribution
of the incoming electrolyte, a plate, V, is riveted upon and along
the bottom of the bath; over this plate is another ono, U, which
is so attached that there is a little space between the two, the two
thus forming a channel.
With concentrated solutions electrolysis may be commenced with
a current of 100 to 150 amperes per square metre (0'064 to 0*1
ampere per square inch), which may gradually be reduced to 40 or 45