Scientists have discovered that exposing ordinary coal powder to electromagnetic radiation can turn it into a valuable crystalline conductor.
The University of Wyoming recently discovered heating up pulverized coal powder with copper foil in a conventional microwave oven can produce nano-graphite affordably.
A team of researchers first ground some raw coal into a powder, put a small amount onto a piece of copper foil and sealed it in glass containers with a mixture of argon and hydrogen gases. They placed the sample into a microwave oven and heated it for between three and 45 minutes.
“By cutting the copper foil into a fork shape, the sparks were induced by the microwave radiation, generating an extremely high temperature of more than 1800 degrees Fahrenheit (982 degrees Celsius) within a few seconds,” lead author Chris Masi said in a public statement.
The study called “Converting raw coal powder into polycrystalline nano-graphite by metal-assisted microwave treatment” showed sparks create the high temperatures required to transform ordinary coal powder into polycrystalline graphite, with the help of copper foil and hydrogen gas. Several experiments showed heating for 15 minutes produced the best results.
Masi and his study team believe this “one-step method with metal-assisted microwave treatment” proves graphite can be created relatively inexpensively compared to conventional super heating production methods that require petrochemicals, pitch or acetylene. Graphite had a spot price of US$550 (A$708) a tonne compared to coal’s US$98.50 (A$127) a tonne at the time of publication, making the conductor worth 458 per cent more.
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“Finite graphite reserves and environmental concerns for the graphite extraction procedures make this method of converting coal to graphite a great alternative source of graphite production,” they said.
“This method provides a new route to convert abundant carbon sources to high-value materials with ecological and economic benefits.”