Antimony is a chemical element with the symbol Sb (Latin: stibium, meaning “mark”) and atomic number 51. A metalloid, antimony has four allotropic forms. The stable form of antimony is a blue-white metalloid. Yellow and black antimony are unstable non-metals. Antimony is used in flame-proofing, paints, ceramics, enamels, a wide variety of alloys, electronics, and rubber. Antimony in its elemental form is a silvery white, brittle, fusible, crystalline solid that exhibits poor electrical and heat conductivity properties and vaporizes at low temperatures. A metalloid, antimony resembles a metal in its appearance and in many of its physical properties, but does not chemically react as a metal. It is also attacked by oxidizing acids and halogens. Antimony and some of its alloys are unusual in that they expand on cooling. Antimony is geochemically categorized as a chalcophile, occurring with sulfur and the heavy metals lead, copper, and silver. Estimates of the abundance of antimony in the Earth’s crust range from 0.2 to 0.5 ppm. Even though this element is not abundant, it is found in over 100 mineral species. Antimony is sometimes found native, but more frequently it is found in the sulfide stibnite (Sb2S3) which is the predominant ore mineral. Commercial forms of antimony are generally ingots, broken pieces, granules, and cast cake. Other forms are powder, shot, and single crystals.
Native massive antimony with oxidation products
Applications – Antimony is increasingly being used in the semiconductor industry in the production of diodes, infrared detectors, and Hall-effect devices. As an alloy, this metalloid greatly increases lead’s hardness and mechanical strength. The most important use of antimony is as a hardener in lead for storage batteries. Uses include:
* antifriction alloys
* type metal
* small arms and tracer ammunition
* cable sheathing
* medicines, antiprotozoan drugs
* soldering – some “lead-free” solders contain 5% Sb
* main and big-end bearings in internal combustion engines (as alloy)
* used in the past to treat Schistosomiasis; today Praziquantel is universally used
* used in linotype printing machines
Antimony compounds in the form of oxides, sulfides, sodium antimonate, and antimony trichloride are used in the making of flame-proofing compounds, ceramic enamels, glass, paints, and pottery. Antimony trioxide is the most important of the antimony compounds and is primarily used in flame-retardant formulations. These flame-retardant applications include such markets as children’s clothing, toys, aircraft and automobile seat covers. It is also used in the fiberglass composites industry as an additive to polyester resins for such items as light aircraft engine covers. The resin will burn while a flame is held to it but will extinguish itself as soon as the flame is removed. Antimony sulfide is also one of the ingredients of safety matches.
RESOURCES IN INDIA
Presently, there is no production of Antimony in India. The entire requirement of antimony in the country is met through imports of its ore and concentrates. As per the UNFC system, as on 1-4-2005, total resources of 10,588 tonnes ore with metal content of 174 tonnes are estimated in Lahaul & Spiti, Himachal Pradesh.