Satellites demand durable components, and for some applications the metal rhenium is irreplaceable. But it is hard to smelt, as well as being rare. Its current price of US$1.45 per gram reflects its conventional extraction from gases emitted by roasting molybdenum ore, a by-product of copper mining. At around one sixth the value of gold and with work beginning in earnest on the US-Russian International Space Station, a sizeable chunk of rhenium promises a quick profit. For geologists in the economic black hole that was the Soviet Union, rhenium has become a magnet and they are developing possibly the most extraordinary mining venture ever attempted.
Volcanologists of the Russian Institute of Experimental Mineralogy discovered, in 1992, that fumaroles of the volcano Kudriavy in the Kuril Archepelago exhale and precipitate pure rhenium sulphide – the hitherto unknown mineral rheniite. The vents’ build-ups contain at least ten tonnes of rhenium, and fumarole gases replenish it at a rate of several grammes each day. As well as mining the vents, even condensing rheniite is an economically attractive proposition. Even now, scientists of the Moscow-based Institute of Mineralogy, Geochemistry and Crustal Chemistry are building a wooden pyramid to cap one of the vents. This will funnel fumarole gases into a chemical trap for rhenium, that uses zeolites as an ion extractor. Future plans, sensibly, focus on concrete or ceramic caps to tap all the fumaroles in Kudriavy’s crater.
Source: Jones, N., 2000. Outrageous fortune. New Scientist, 26 August 2000, p 24-26