The problem with antimony

Materials World magazine
,
1 Apr 2015

In the second instalment of our Elements of risk series, Eoin Redahan finds there could be a serious shortage of antimony in little more than a decade.

Many early alchemists were monks. When these holy men worked their golden way, they encountered poisonous substances that were far from pleasant. Antimony was one of these and came to be known
as ‘monk killer’. 

Some claim the word antimony signifies something else. They say it means ‘against aloneness’, as it rarely appears in high concentrations on its own. Antimony is found in more than 100 mineral species, including copper, lead, silver and gold, though its abundance in the Earth’s crust is only 0.2–0.5 parts per million. 

Nevertheless, this silvery-white semi-metal is widely used. It strengthens lead alloys, acts as a catalyst in the production of PET and is prevalent in flame retardant materials. But, despite playing an important role in our daily lives, it is not mined in huge quantities. 

According to the US Geological Survey (USGS), the USA produced no marketable antimony in 2014, and there is not much antimony in Europe either. It ranks third on the British Geological Survey Risk List and is on the EU’s list of critical materials. 

Better get digging

Unsurprisingly, China mines the majority of the world’s antimony. It may have accounted for 80%of global production last year, but it did not export very much of it. To make matters even more troubling, at the current rate of consumption, the world’s antimony reserves could be spent in little more than a decade. 

Few fear that we will actually run out of antimony any time soon. New projects will come on stream when the need increases and some will continue to recover it from secondary sources, such as recycled lead-acid batteries.  

Greenfield and brownfield projects are underway in several countries including Australia, Myanmar (Burma), Canada and Italy, but the most significant undertaking is in Oman, where London-based Tri-Star Resources will produce 20,000 tonnes of antimony a year from 2016 – about 12% of the global market. 

Antimony will also become more attractive to mining companies if the price rises as predicted. In 2004 it fetched US$2,870 a tonne, while it sells for about $8,000/t today, despite recent price falls. According to Canadian exploration company Goldstar Minerals, the price could reach $25,000/t by 2020. 

These high prices could come to pass if several nascent technologies continue to grow. Antimony
is being used in phase-change memory devices, which could dramatically increase computing speeds. It is also being used in one of the electrodes for MIT’s liquid metal battery, which aims to provide a grid-level storage solution for renewable energy sources.

So, with antimony prices set to rise in the next five years, it might be worth spending some of your spare savings on the shiny monk killer.