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

166 THE METALLURGY OF ANTIMONY.
powdered bismuth, 24 parts of powdered stibnite, and 64 parts of
saltpetre is melted and is poured, while molten, into water. The
mass thus obtained is brittle and is finely powdered, washed and
dried, and is melted with 128 parts of litharge and 8 parts of sal
ammoniac. This yellow pigment has almost fallen into disuse,
because of its instability and the high price of bismuth.
(8) The yellow pigment can also thus be obtained :—Melt together
16 parts of litharge, 1 part of sal ammoniac, \ part of antimonate of
bismuth (obtained by heating a mixture of 30 parts of bismuth, 240
parts of antimony sulphide, and 640 parts of nitre), and, after
complete.fusion, pour into water.
(c) Antimony Yellow of a Permanent Character (Fr. jaunes fixes).—
This can be obtained by employing antimonic acid, produced by treating
the perchloride of antimony with water and the residue with
hydrochloric acid. It can also be prepared by slowly calcining
antimonate of protoxide of iron, obtained by double decomposition,
in the air. The result thus obtained is very resistant to the action
of sulphurous vapour. When chloride of antimony is treated with
a current of sulphuric acid vapour, the resulting pigment is still
more resistant to the action of sulphurous vapour. Sulphuric acid,
which, as a rule, is very injurious to Naples yellow and blackens it,
is in this case a good agent for vivifying the colour. Various hues
of yellow pigment can be obtained by adding to it an oxysulphide
formed by the action of sulphantimonate of sodium in a solution
of sulphate of zinc. The precipitate is a very deep orange-yellow,
very insoluble, and is dried at 50°. A mixture of this with the
persulphide in various proportions will produce hues of colour from
lemon-yellow to orange yellow.
(e) Antimony Blue.—This pigment is, as yet, without an equal in
the manufacture of artificial flowers. It is thus produced:—A dilute
solution of potassium ferrocyanide is added to a clear solution of
metallic antimony in aqua regia. According to Krauss, this is merely
a Prussian blue obtained from the ferrocyanide used, which is decomposed
by the strong acid, with evolution of hydrocyanic acid, the
antimony thus possessing no colouring principle.
(/) Antimony Violet.—This is obtained by mixing antimony vermilion
and either antimony blue or other kinds of blue together.
(g) Antimony Green.—This is obtained by the mixing of antimony
yellow and antimony blue in different proportions.
(A) Antimony Orange.—R. Wagner recommended the use of
sulpho-antimonite of barium mixed with artificial sulphate of baryta
[Mane fixe) as furnishing good pigments for painting.