Spinning Precious Metal Out Of Hot, Thin AirPetti Fong
Miners have always worked under tough conditions, but in a volcano? Russian scientists are doing so in an effort to capture rhenium--a very rare, highly durable metal used in high-stress environments such as satellites, jet engines, and gas-fired turbines. The Russians are extracting the metal from noxious gases belching from a volcano in the Kuril Archipelago, north of Japan.
Mikhail A. Korzhinskii, a scientist at the Institute of Experimental Mineralogy in Chernogolovka, 30 miles north of Moscow, and his colleagues have known since the early 1990s that the Kudriavy volcano spits up a few grams per day of rhenium sulfate, which is 77% rhenium by weight. But some of the rheniite, as it has been dubbed, escapes as gas. About six micrograms are lost in each liter of vapor that vents away--and at $1,450 per kilogram, that's nothing to sneeze at. So Korzhinskii's team plans to cap the vent with an insulated wooden dome and capture the rhenium using a filter made of zeolite, an absorbent natural mineral. Their goal is to recover two tons a year, or nearly $3 million worth. If it works, this would add 4% to worldwide production levels of rhenium--and just when demand for it is growing.
Tom A. Millensifer welcomes all this superheated air. A technical adviser at Rockford (Ill.)'s Powmet Inc., the leading U.S. distributor of rhenium, he says: "I was invited to go there several years ago and thought: `You have to be crazy to think about going to the edge of an active volcano."' Now, he says, "it seems like what they're doing could be feasible."