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

102 THE METALLURGY OF ANTIMONY.
An analysis of an average sample of the oxide from the other
chambers gave *5 per cent, of impurity.
Total quantity of oxide obtained:—
1st experiment 424 kgs.
2nd 602 „
Dried oxide (from tanks) . . . 178 „
Cleanings . . . . . . 32 ,,
Estimated cleanings . . . . 5 „
1241 kgs.
The amount of ore treated was :—
1st experiment 2850 kgs.
2nd 2725 „
5575 kgs.
The actual quantity of pure oxide obtainable was:—
1241 - [(76 +176) x -23 + (989 x -005)]
= 1241-(58 + 5)
= 1178 kgs. of pure oxide, -which is equivalent to about 981 kgs. of pure Sb.
Now, since the ore analyses recorded 19-5 per cent. Sb, then in
5575 kgs. of ore there are 1087 kgs. of Sb.
Hence the percentage loss is :—
1087- 981 x 100 = a littie less tllan 10 per c^
Again, the scoria, when analysed, was found to contain only
1*3 per cent, of Sb, which is equivalent to 52 kgs. of Sb considered
as loss in the scoria (52 = 1 *3 per cent, x 4000 kgs. of scoria).
Most probably, if the different parts of the apparatus were
thoroughly cleaned of their oxide, the loss would not be more than
5 per cent.
Practically, in twenty-four hours 5| tons of such ore can be treated,
witih a consumption of 4 per cent, charcoal. It is most probable that
at least 7 tons could be treated per day, if the rate of revolution of
the ventilators were increased from 1200 to 1400 per minute.
The reason why charcoal was used in these experiments is that,
although gas coke gives better results from an economical point of
view, it is not easily obtainable in some of the out-of-the-way places,
where perhaps the price of charcoal is not very far above that of
gas coke, if not actually less
Generally speaking, it costs about 70 francs to produce one ton of
oxide by this process in France.
The complete apparatus described above costs 10,000 francs.