McGill University, Montreal, announces that a team of chemists has developed a way to process metals with organic molecules, instead of chlorine and hydrochloric acid, to help purify germanium. The system also taps into mechanochemistry, an emerging branch of chemistry that relies on mechanical force – rather than solvents and heat – to promote chemical reactions. This technology is based on milling jars containing stainless-steel balls. The jars are shaken at high speeds to help purify the metal. Laboratory experiments have shown that the same techniques can work with other metals, including zinc, copper, manganese, and cobalt.
The system, which also consumes far less energy than conventional techniques, could greatly reduce the environmental impact of producing metals from raw materials or from post-consumer electronics.
“At a time when natural deposits of metals are on the decline, there is a great deal of interest in improving the efficiency of metal refinement and recycling, but few disruptive technologies are being put forth,” says Jean-Philip Lumb, an associate professor in McGill University’s Department of Chemistry. “That’s what makes our advance so important.”
The discovery stems from a collaboration between Prof. Lumb and Tomislav Friščić at McGill in Montreal, and Kim Baines of Western University in London, Ontario. In an article published recently in Science Advances, the researchers outline their approach.
The research could mark an important milestone for the “green chemistry” movement, which seeks to replace toxic reagents used in conventional industrial manufacturing with more environmentally friendly alternatives. Most advances in this area have involved organic chemistry – the synthesis of carbon-based compounds used in pharmaceuticals and plastics, for example.
No single ore is rich in germanium, so it is generally obtained from mining operations as a minor component in a mixture with many other materials. Through a series of processes, that blend of matter can be reduced to germanium and zinc.
“Currently, in order to isolate germanium from zinc, it’s a pretty nasty process,” Prof. Baines explains. The new approach developed by the McGill and Western chemists “enables you to get germanium from zinc, without those nasty processes.”