A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...
A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...
A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...
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112 THE METALLURGY OF ANTIMONY.<br />
Balls, about the size of an egg, are made of tho following<br />
composition :—<br />
The trioxide 82 per cent.<br />
Carbon (anthracite or powdered charcoal) . .12 ,,<br />
Carbonate of soda 6 to 7 ,,<br />
These balls are charged into the furnace with 5 to 20 per cent,<br />
coke. The loss of oxide is about 33 per cent., which can be recovered<br />
from the condensing chambers, as shown in fig. 45.<br />
The metal thus obtained has to be remelted, either in a crucible<br />
or in a reverberatory furnace, for the purpose of " starring."<br />
(c) Reduction in Crucibles.—This method, on account of its high<br />
cost, is only adopted when the ores are rich or when crude antimony<br />
or the volatile oxide is available. The use of crucibles and pot<br />
furnaces precludes the possibility of working large quantities.<br />
The roasted ore is fused with 10 per cent, of its weight of crude<br />
argol, or with charcoal or anthracite and potash or soda, in crucibles<br />
made of fire-clay, heated in a wind furnace or in a galley furnace.<br />
The mould in which the melted metal is cast must be coated with<br />
tallow or with a thin layer of fire-clay cream.<br />
According to Knab, we have the following :—<br />
One crucible contains 26*5 lbs. of roasted ore, with 10 per cent, of charcoal<br />
and 7 '15 per cent, of salt or soda.<br />
Pots are arranged 10 or 12 in each furnace.<br />
Each pot turns out 4 or 5 charges in 24 hours.<br />
Consumption of coal, 70 to 80 per cent, of weight of ore.<br />
Life of each pot, 7 or 8 charges.<br />
A new process * just discovered by Herrenschmidt consists of<br />
melting, in a crucible, balls of the following composition :—<br />
Antimony oxide.<br />
Powdered anthracite.<br />
Carbonate of soda.<br />
Water.<br />
The decided advantage of this process is that the "starring" of<br />
the metal can be effected in a single operation.<br />
The furnace used is shown in fig. 53.<br />
2. Extraction of Metallic Antimony from Antimonium Crudum.<br />
—This method is only applicable to rich ores and crude antimony.<br />
The following process to be described involves the use of rich ore; if<br />
crude antimony is under consideration, the composition of tho charge<br />
* The author is under obligation not to give the details until tho patent is<br />
taken.