[90] Bastin, E. S.: “Antimony in 1918,” Mineral Resources of the United States, 1918. U. S. Geol. Survey, 1919.
Peace uses.—Metallic antimony unalloyed has few industrial uses. In the form of fine powder, known as “iron black,” it is used for producing the appearance of polished steel on articles made of papier-maché or pottery. For these purposes it is precipitated by the action of metallic zinc in an acid solution of antimony salts. Antimony alloys readily with most heavy metals and the alloy is harder than the two pure metals. Most of these alloys possess the property of slight expansion on solidifying. Type metal is an alloy of antimony, lead, and tin; babbitt, anti-friction, or bearing metal is usually an alloy of antimony, tin, and copper. Britannia metal, also known as “white metal,” is an alloy of antimony, tin, and copper, with some zinc, and, rarely, small quantities of other metals. It is used in making cheap domestic tableware, teapots, and spoons. Antimony alloys find minor utilization in battery plates, toys, cable coverings, and siphon tops. Lead-antimony alloy or hard lead is used in making acid-resisting valves.
White antimony oxide, mainly the tetraoxide (Sb2O4), is used for making opaque white enamel and other sanitary ware. In this use antimony oxides compete with tin oxide. Antimony oxide, mainly trioxide, is used as a coloring agent in the manufacture of glass, as it is more readily fusible than tetraoxide and does not impart opacity to the glass. Antimony oxides are further used as paint pigments.
The red sulphides of antimony are used in vulcanizing and coloring red rubber and also as paint pigments. The natural antimony trisulphide, stibnite, enters into the composition of safety matches or of the compound that is put on the match box.
Antimonate of lead containing an excess of lead oxide, known as “Naples yellow,” is used in oil paints and in the glass and ceramic industries. The antimony salt, tartar emetic (double tartrate of antimony and potassium), and antimony fluoride are employed as mordants in dyeing. Tartar emetic and antimony trioxide are employed medicinally.
War uses.—Antimonial lead carrying 12 to 13 per cent. of antimony is employed in the manufacture of shrapnel bullets. Smaller quantities of liquated antimony sulphide are used in the primers of shells. For this last purpose it is claimed the material must carry less than 2 per cent. of impurities insoluble in hydrochloric acid. Antimony sulphide as a powder is used in the charge of some shells to produce on explosion a white smoke which is of service in range finding.
During the war Germany used antimony to some extent as a substitute for more important metals in the manufacture of currency, but shortage of antimony itself did not allow this use to become important.
GEOLOGICAL DISTRIBUTION
The geological distribution of commercial antimony depends, with a few exceptions, upon the distribution of the principal ore mineral, stibnite (antimony sulphide). Cervantite, sernarmontite and valentinite are antimony oxides resulting directly from the decomposition of stibnite near the surface, and with other oxidized products form the chief ores of certain districts. Metallic antimony, also a result of oxidation of the sulphides, is rarely found, and still more rarely is it an ore mineral. Jamesonite, the sulphide of antimony and lead, is of frequent occurrence and is the principal ore of one important deposit in Mexico. Antimony is also recovered from the refining of antimonial lead.
Stibnite occurs in quartz veins and related deposits. Many of the important antimony deposits of the world occur in more or less close genetic relationship with eruptives of Tertiary age. The ore often gives way to pyrite with depth. A few important deposits occur in connection with intrusive rocks formed at considerable depth and are probably of contact metamorphic origin.