This “one-step method with metal assisted microwave treatment” is a new approach that, in their opinion, could represent a simple and relatively inexpensive coal conversion technology to make good use of coal from the Pó de Rio Basin Wyoming.
According to the team led by TeYu Chien at the University of Wyoming, although previous research has shown that microwaves can be used to reduce the moisture content of coal and remove sulfur and other minerals, most of these methods require specific chemical pretreatment of coal. In his experiment, however, the only treatment carried out was to grind the Powder River Basin raw coal into powder.
This powder was then placed on a copper foil and sealed in glass containers with a gaseous mixture of argon and hydrogen, before being placed in the microwave oven.
“When cutting the fork-shaped copper foil, the sparks were induced by microwave radiation, generating an extremely high temperature of over 1,800 degrees Fahrenheit in a few seconds,” said Chris Masi, the article’s lead author, in a statement to the press. media .
The high temperatures then transformed the coal powder into polycrystalline graphite, with copper foil and hydrogen gas also contributing to the process.
The group – which also includes researchers from New York, Nepal and China – believes that this new method of converting coal could be refined and carried out on a larger scale to produce nano-graphite materials in higher quality and quantity.