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 ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
70 THE METALLURGY OF ANTIMONY.<br />
perature is too low the residue will contain too large a proportion<br />
of antimony, part of which at least should go to the liquated<br />
product as crude antimony. It has already been mentioned that<br />
the best size of the pieces of ore is that of walnuts; for, if the<br />
size is in any way smaller, the liquation process is less complete, and<br />
hence the residues are too rich in the sulphide ; furthermore, fine ores<br />
lie so close together as to render the escape of the fused sulphide<br />
difficult.<br />
(a) Intermittent Working.<br />
As a rule, closed furnaces use more fuel and cost more for labour<br />
than open ones (reverberatory), which, on the other hand, lose more<br />
antimony through volatilisation and oxidation than closed ones.<br />
This loss can, however, be eliminated by the use of the condensation<br />
apparatus of Herrenschmidt, to be mentioned later.<br />
The smelting is done in pots, which are either heated directly by<br />
the burning fuel or by the flame coming from a fireplace. In the<br />
liquation in pots, the working is carried on intermittently, while<br />
continuous working is permitted in that of tubes or reverberatory<br />
furnaces, thus economising the consumption of fuel.<br />
a. Intermittent Liquation in Pots in Open Fire.—Pots, being in<br />
direct contact with the fuel, are used at Wolfsberg in the Harz, at<br />
Magurka. Eosenau, and Gross-Gbllnitz in Hungary, at Milleschau in<br />
Bohemia, and at Malbosc<br />
in France. The only merit<br />
of this method is its simplicity,<br />
and for this reason<br />
it can be carried on without<br />
much difficulty at the<br />
mines. If the ores are<br />
rich and fuel (wood or<br />
coal) is cheap at" the mine,<br />
this method can be used<br />
with advantage.<br />
FIG. 3. The pots are made of<br />
fire-clay, and are able to<br />
hold from 11 to 36 lbs. There are in the bottom of each pot four or<br />
five holes, each varying from 0-4 to 0-6 inch in diameter, through which<br />
the molten sulphide escapes. Below these pots rest receivers, made<br />
of burnt clay, for the collection of the liquefied crude antimony.<br />
These receivers are embedded in sand, ashes, or breeze, thus ensuring<br />
the slow cooling of their contents. The pots are arranged in several