Antimony Properties

Antimony’s striking property of expanding, rather than contracting, upon cooling makes it desirable for making type metal alloy, which when cast does not change size. Its main use is to impart stiffness and hardness to various lead alloys, thus permitting lead to be used for purposes not otherwise possible. Antimonial lead or hard lead contains 1 to 25 % antimony, produced by alloying the two metals or by smelting mixed antimony and lead ores.

The chief uses for Sb-Pb alloys are: storage battery plates, sheets and pipes, sheathings for electrical cables, collapsible tubes (toothpaste), foil, bullets, type metals (10-15% Sb), solder and anti-friction bearings.

Antimony compounds are also used for flame-proofing, pigments, enamels, safety matches, glass, vulcanizing and medicines. Military uses include shrapnel balls and bullet cores, detonating caps, and bursting charges of shrapnel to yield the dense white marker smoke.

Mineralogy, Tenor and Treatment

There are many Sb minerals but stibnite and lead ores yield most of the commercial metal. Native antimony and oxidation products, such as cervantite, contribute a little. Ores range in tenor from 3 to 8% and are hand sorted or concentrated; the sulphide product is enriched by liquidation, whereby the low-temperature melting point of stibnite permits the melt to drain off from unfused enclosing substances. This produces crude antimony. Low grade ores are roasted to the oxide. Antimony metal is produced by smelting the oxide or the crude or high grade sulphides in a blast furnace with iron, which unites with the oxygen or sulfur, freeing the antimony. Oxide and electrolytic antimony are now recovered by the “Lee-Muir” process, which separates the components of tetrahedrite.