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

THE METALLURGY OF ANTIMONY. 117
by the workmen. The flues generally require cleaning four times
a year.
In the process described above, the first operation of smelting the
ore with iron is called "singling," the second operation, or resmelting
the singles for the production of the bowl metal, is called "doubling,"
and the last operation is called "refining" or "frenching."
On an average, one man can smelt 10 to 11 cwts. of ore in twelve
hours. It has been observed that a small quantity of the oxide
mixed with the sulphide improves the appearance of the metal.
The following table shows the number of men required to work a
furnace:—
Firemen . . . ' .
Furnacemen . . . .
Refiners
Metal-breakers . . . .
Charge-mixer . . . .
Workers on day-shift only, viz. \
one smith, one boiler and engine- >man,
and three labourers J
Per Side of
the Furnace
per Shift,
12 Hours.
1
4
For the Whole
Furnace per
Shift,
12 Hours.
2
2 1
Total
Per
Day of
24
Hours.
At Magurka, in Hungary, the precipitation method was formerly
in use; pot furnaces and graphite crucibles were employed. The
charges consisted of 20 to 22 lbs. of antimony sulphide, with iron,
potash, and pan scale (from salt-works). There were only two
operations in the process.
At Linz and Schleiz in Germany, and at Alais in France, reverberatory
furnaces are still in use. There is a great loss due to volatilisation
in these furnaces; and hence condensing flues are connected with
the furnaces for the collecting of the metallic fume. The bed must
also be tight enough to prevent any loss due to leakage.
According to M. Herrenschmidt, it is better to cover the bed of
the reverberatory furnace with a thin layer of regulus in order to
prevent the corrosion of the scoria.
3. Direct Processes, i.e. Extraction of Metallic Antimony direct
from the Ore.—(a) Bath Furnaces.—T. C. Sanderson has patented * a
process for the smelting of antimony sulphide in a bath of ferrous
* United States patent No. 714,040, Nov. 18, 1902.
4
16 442
5
35