2. On the LARGE SCALE—commercial:—
a. See above (before 1 a.).
b. From sulphide of antimony, 100 parts; iron (in very small scraps), 40 parts; dry crude sulphate of soda, 10 parts; powdered charcoal, 21⁄2 parts; fused together.—Prod. 60 to 65 parts of antimony, besides the scoriæ or ash, which is also valuable.
c. (Berthier.) Sulphide of antimony, 100 parts; hammerschlag (rough oxide or iron from the shingling or rolling mills), 60 parts; crude carbonate or sulphate of soda, 45 to 50 parts; charcoal powder, 10 parts; as last.—Prod. 65 to 70 parts.
Prop., &c. Bluish-white, lustrous, with a lamellar texture, and a crystalline or semi-crystalline fracture, with fern-leaf markings on the surface, when pure (star antimony); extremely brittle (may be powdered); imparts brittleness to its alloys (even 1-1000th part added to gold renders it unfit for the purposes of coinage and the arts); melts at 809-810° Fahr., or just under redness; fumes, boils, and volatilises at a white heat, and, when suddenly exposed to the air, inflames with conversion into the teroxide, which is deposited in beautiful flowers or crystals; when perfectly pure and fused without contact with air or foreign matter, it bears an intense heat without subliming (Thénard); allowed to cool slowly from a state of perfect fusion, it crystallises in octahedrons or dodecahedrons; tarnishes, but does not rust by exposure to air or moisture at common temperatures; hot hydrochloric acid dissolves it, with the formation of TRICHLORIDE OF ANTIMONY; nitric acid, when concentrated, converts it into ANTIMONIC ACID; and when
dilute, into TRIOXIDE OF ANTIMONY. Sp. gr. 6·7 to 6·8.[69]
[69] When perfectly pure, 6715—Ure.
Tests. Metallic antimony may be recognised by the above properties; its oxide, salts, &c., by the following reactions:—1. Sulphuretted hydrogen gives, with acid solutions, an orange-red precipitate, which is sparingly soluble in ammonia,[70] and insoluble in dilute acids; but readily soluble in pure potassa and alkaline sulphides, and in hot hydrochloric acid with the evolution of sulphuretted hydrogen gas:—2. Sulphydrate of ammonium gives an orange-red precipitate, readily soluble in excess of the precipitant, if this latter contains sulphur in excess; and the liquor containing the re-dissolved precipitate gives a yellow or orange-yellow precipitate on the addition of an acid:—3. Ammonia and potassa, and their carbonates, give (except in solutions of tartar emetic) a bulky white precipitate; that with ammonia and its carbonate being insoluble in excess of the precipitant; that with potassa, readily so; whilst that with carbonate of potassium is only soluble on the application of heat:—4. A rod of zinc throws down metallic antimony, as a black powder, from all its solutions not containing free nitric acid. If the experiment be made with a few drops of a solution of antimony containing a little free hydrochloric acid, and a small platinum dish or capsule be employed, the part covered by the liquid is soon stained brown or blackish, and the stain is irremovable by cold hydrochloric acid, but may be easily removed by warm nitric acid:—5. By ebullition of the acidulated liquid along with copper gauze, foil, or wire, as noticed under ‘Reinsch’s Test.’[71] The peculiar violet-grey of the deposit is characteristic, and may easily be distinguished from that given by arsenical solutions:—6. Mixed with dilute sulphuric acid and poured on some metallic zinc in a gas-generating flask, provided with a small bent tube (see engr.), it yields ANTIMONETTED HYDROGEN (Marsh’s test), recognised by burning with a bluish-green flame, and furnishing dense white fumes which adhere readily to any cold substance (as a porcelain plate) held over it; or, if the plate be depressed upon the flame, a deep black, and almost lustreless spot of metallic antimony; the fumes and spots in both cases being insoluble in water, and in dilute solution of chloride (crude hypochlorite) of soda. On heating the centre of the tube to redness with a spirit lamp, the bluish-green colour of the flame lessens in intensity, and a mirror of metallic antimony, of silvery lustre, forms inside the tube at the ignited part. On passing dry sulphuretted hydrogen through the tube, still heated by a spirit lamp, this mirror assumes a reddish-yellow colour, approaching black in its thicker parts; and by exposure to a feeble stream of hydrochloric acid gas, almost immediately, or in a few seconds, disappears, being carried off by the gas, which, if passed into a little distilled water, yields a solution of chloride of antimony, which may be further submitted to any of the usual tests.[71] If the substance be in the solid state, it must be reduced to powder and dissolved in water; or if insoluble in that menstruum, a solution must be obtained by digestion in either hot hydrochloric or nitrohydrochloric acid, before proceeding to examine it by this method.
[70] The like precipitate from a solution of antimonic acid in hydrochloric acid, dissolves readily in ammonia, particularly when heated.
[71] See Arsenious Acid.