ANTIMONY, one of the metallic elements. It is found in nature in the metallic state, but its chief commercial source is the mineral stibnite, which is a sulphide of antimony (Sb.S.). Considerable of the metal is pro duced as a by-product in the smelting of lead silver ores. The mineral stibnite occurs in veins, commonly associated with other metallic minerals. Stibnite was known in very early times. It has been used by the women of the East for many centuries for painting the eyebrows and eyelashes and giving lustre to the eyes. Before the discovery of the metal itself, stib nite was called and it appears that the paint used by Jezebel (2 Kings ix, 30) was finely round stibnite. The Arabs called this face-paint al Kohl (compare ALCOHOL) . The first distinct mention of the metal itself is made by Basil Valentine, who gives a process for extracting it from stibnite, though he does not claim to have discovered it. Several methods for extracting it are now in use, chief of which is the following: Two parts of stibnite are melted with one part of thin scrap iron, in plumbago crucibles. The sulphur, leaving the antimony, combines with the iron, so that sul phide of iron and metallic antimony result, the iron sulphide floating as a slag. The crude antimony so obtained is next melted with a small amount of sulphate of soda and a little of the slag obtained from the operation next to be described. By this means the metal is puri fied somewhat. It is then cast into molds, and when cold is broken up into small pieces, to prepare it for the third operation, which is called for star metal') This last named process consists in melting 60 parts of the broken metal with two parts of pearlash and five parts of slag from a previous operation of the same kind. The resulting metal or regulus is poured into square molds, into which some slag has first been allowed to run, and is cooled slowly, while still covered with slag. If the metal is of good quality, the resulting blocks will have a stellated or crystalline sur face.
Antimony is a brilliant, bluish-white, brittle, crystalline metal, with a specific gravity vary ing from 6.72 to 6.86. It melts at about 800° F., and if protected from the air boils at a white heat. At ordinary temperatures it is not acted upon by air or water, but it oxidizes quickly when melted, and at a red heat burns at a brilliant white flame, and can decompose water. It expands upon solidifying, and im parts this property to its commoner alloys. Its coefficient of expansion is about .0000064 per
degree F. The tensile strength of cast anti mony is about 1,000 pounds per square inch of sectional area. It is a comparatively poor con ductor of heat and electricity, its thermal con ductivity being only about 1/25 of that of its ts electrical resistance is 0.488 of that of mercury at 32° F., and 0.704 that of mercury at 212° F. Its chemical symbol is Sb (from the Latin word stibium), and its atomic weight is sensibly 120. It is diamagnetic; that is, a sphere made from it is repelled by a magnet, though the repulsion is hardly com parable in magnitude with the force of attrac tion that a magnet exerts upon iron. It also has marked thermoelectric properties, and is used in the laboratory in the construction of thermopiles. Antimony forms valuable alloys with other metals, and this is its most import ant use in the arts. Type metal is an alloy of lead, antimony, and tin, with sometimes a little copper. The tin adds toughness, while the an timony gives hardness and causes the alloy to expand at the instant of solidifying, giving a sharp cast of the letter. In the manufacture of munitions of war antimony plays an im portant part. It is employed to give to shrapnel bullets the hardness through which they retain their spherical shape when the shell explodes. Previous to the European War the annual pro duction of metallic antimony in the United States was between 2,000 and 3,000 tons— obtained mainly from antimonial lead. With the growth of the munition making industry the demand for the metal increased rapidly, and in 1915 the total production reached 18,600 tons. About 5,000 tons of this total was produced in domestic mines in Inyo, Kern and San Benito counties of California; in Hum bolt and Elko counties of Nevada; and at points less notable in Arkansas, Idaho, Mon tana, Oregon, Utah and Washington. A larger degree of interest, however, attached to the output of Alaska, amounting in that year to 1,390 tons of stibnite, carrying nearly 60 per cent of metallic antimony from this entirely new source. A large factor in the total was 8,500 tons from China. South America and Mexico supplied nearly all the rest. The an timony prospects of Alaska are considered most promising, and the showing for 1916 should be much larger, when the smelter returns have been compiled. Besides the localities men tioned, antimony is found in France, Australia, Japan, China, Italy, Spain, Portugal and South Africa. See ELECTROCHEMICAL INDUSTRIES.