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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THE ANTIMONY PREPARATIONS AND THEIR USES. 167<br />
This pigment can be produced thus :—<br />
Finely powdered sulphate of baryta . .2 parts.<br />
Native sulphide of antimony . . . . 1 part.<br />
Powdered charcoal . . . . . . 1 ,,<br />
This mixture is calcined in a crucible of clay or graphite for several<br />
hours up to red heat. The crucible should remain closed until it<br />
becomes cold, because the carbonaceous matter contained in it might<br />
become inflamed, with explosion, if it remained open. The calcined<br />
mass is then boiled in water, and the insoluble residue—the sulphide<br />
of barium and calcium—is used in the mixing of the material for<br />
another operation. The filtered liquid has a pale-yellow colour.<br />
Dilute sulphuric acid is then added to it until the orange colour is<br />
entirely precipitated. The colour thus produced is mixed with blanc<br />
fixe. If a purer orange hue is desired, the solution of sulpho-antimonite<br />
of barium is boiled with \ part of sublimed sulphur. The sulphoantimonite<br />
of barium is then transformed into sulpho-antimonate,<br />
which has a composition analogous to that of Schlippe's salt.<br />
A yellowish orange colour is obtained when, a dilute solution of<br />
sulpho-antimonate of sodium is treated with a mixture consisting<br />
of 1 kilo, of quicklime, dissolved in 25 litres of cold water, 1 kilo, of<br />
sulphate of iron protoxide, 1 kilo, of sulphate of zinc, and alum in<br />
amount varying according as the colour is required to be of a more<br />
yellowish or less red hue.<br />
(i) Orange-red Sulphide of Antimony.—The patent of MM.<br />
Leclaire and Barruel is to the following effect:—1 part of natural<br />
Sb^Sg is pulverised and dissolved, with the aid of heat, in 7 parts of<br />
hydrochloric acid at 20° Be. The hydrogen sulphide given off from<br />
the first operation is condensed in a solution of milk of lime. When<br />
all the sulphide is dissolved, the acid solution of antimony chloride is<br />
poured into stoneware vessels which have holes at different heights.<br />
The liquor is diluted with water until it becomes turbid and a white<br />
precipitate appears. Then this is put into demijohns and is submitted<br />
to a stream of hydrogen sulphide. The liquor is occasionally<br />
stirred with a wooden stick, and the vessels covered to prevent the<br />
escape of the hydrogen sulphide, which is, however, led to a solution of<br />
milk of lime by means of tubes, and is absorbed therein. The sulphide<br />
thus obtained is washed and dried in a stove-room heated to from<br />
40° to 50° C, but not higher; otherwise it loses much water and turns<br />
black.<br />
(?) Miscellaneous Pigments.—(a) A yellowish-red pigment can<br />
be obtained by melting a mixture of 8 parts of the oxide with 2<br />
parts of the sulphide together. This is known as crocus.