(excerpts from article)

Antimony: A Metal?

"Antimony Speculators Lose Out"

Speculators who tied up large sums of money in Chinese antimony, which is used in the making of ammunition, in the hopes of reaping great profits are now ruing their greediness...

–New York Times

So reported a recent story in the New York Times.

Well, that's recent in relation to the history of antimony. In absolute terms, however, the story was actually published some 92 years ago, on November 25, 1917. Interestingly, antimony is still used in ammunition, and China remains the metal's primary source.

Estimated World Mine Production of Antimony in 2008 (Thousand Tonne)

Source: U.S. Geological Survey (USGS)

A Very Brief History of Antimony

Pure antimony metal is silver gray/white and brittle.

Although actually a metal, like germanium and tellurium (of which more in forthcoming articles), antimony is also termed a metalloid. (A metalloid displays the characteristics of both a metal and a nonmetal.) In addition, it has four allotropes (see Gallium: A Slippery Metal), of which two (yellow antimony and black antimony) are neither stable nor metallic. Indeed, yellow antimony, which only occurs at temperatures below -80°C, is extremely explosive.

Antimony has been known of, and used, from at least the third millennium BCE. Back then it was used, amongst other things, in eye shadow (kohl) and for medicinal purposes. (More recently it has been used in the treatment of bilharzia (schistosomiasis), a particularly nasty disease caused by parasitic worms that can spread throughout most of your body.) Antimony and its compounds can, however, be particularly toxic.

From the Middle Ages on, antimony has also featured strongly in alchemy and, indeed, the metal has a number of symbols of its own.

These days, antimony is used for a number of other, different, uses.

Its main use is as a flame retardant. When impregnated with compounds formed from antimony trioxide (Sb2O3), plastics, rubber and textiles all become, to a degree, fireproof.

According to the USGS, in 2008, some 40% of the antimony consumed in the U.S. was used in fire retardants. The remainder was accounted for thusly: transportation, including batteries, 22%; chemicals, 14%; ceramics and glass, 11%: and, others, 13%.

Apart from its use in lead-acid batteries, when mixed with lead, the resulting alloy is considerably stronger than either of the two original metals. (It is also mixed with zinc to make other alloys.) These alloys are to be found in such diverse uses as pipe and sheet metal, solder, cable coverings, pewter, castings and bearings (in particular as Babbitt metal), tank linings and, of course, ammunition.

While, in the glass industry, antimony is used to remove the bubbles from, refine and de-color various different types of glass, in ceramic and porcelain glazes it is actually used as an opacifier. (It can also be used to provide yellow coloring.)

In addition to being used as a catalyst in the polyester industry, in chemical form antimony is used in fireworks (antimony trisulfide produces glittering white stars) and can be found, once again, in ammunition, used as a primer - it promotes ignition. (Antimony has, in the past, also been used in the solid propellants that power rockets, for example, as a stabilizer for burning-rate modifiers in the fuel itself.)

Finally, because of its metalloid nature, research continues into further uses of antimony in semiconductors: It is already used as a dopant.

Whence The Antimony?

As with other of the so-called minor metals, most of the world's antimony comes from China; it has for nearly a hundred years. (It is interesting to note, though, that the run-up in the price of the metal those 90 or so years ago stimulated production elsewhere around the globe. One of those places was Bolivia, which remains a major antimony producer.)

In China, one of the largest, if not the largest, antimony mining company is the charmingly named Hsikwangshan Twinkling Star Company in Hunan Province, which owns two major antimony mines. In its February 2008 newsletter, Metal Pages reported that this company alone had the capacity to produce some 1,000 tonnes per month of antimony metal.

While found in over 100 different mineral forms, stibnite (SbS3), an antimony-bearing ore, is the only source for metallic antimony to be commercially mined. Since antimony is often to be found as a trace element in gold, copper, lead and silver ores, the metal is also extracted from these.

At its Workman's Bench antimony/gold deposit located at Nolan Creek in Northern Alaska, Silverado Gold Mines Ltd (Bloomberg Ticker - SLGLF:US), another OTC-traded mining company, recently reported resource and reserve estimates for the antimony there that showed, using the company's assumptions, the metal "would clearly drive the project..."

it may be worth keeping an eye on at least two current uses of antimony. First, its use by the military: In 2006 alone, the country's new import reliance on the metal was 88%. Over the past couple of years this dependence will not have changed significantly. This is an important material for the military. Second, its use in semiconductors: There may be further developments in this area.

Resources

U.S. Geological Survey (USGS)

http://www.hardassetsinvestor.com/features-and-interviews/1428-antimony-a-metal.html