Researchers turn coal into graphite - in a microwave

An international team of researchers has shown that pulverized carbon powder can be converted into high-quality nano-graphite in just 15 minutes. In a study published in the journal Nano-Structures & Nano-Objects, the scientists explain how they created an environment in a microwave oven to successfully convert raw carbon powder into nano-graphite, which is used as a lubricant and in items in fire extinguishers to lithium-ion batteries. This "one-step, metal-assisted microwave treatment" approach is a new approach that they believe could provide a simple and relatively inexpensive coal conversion technology to make good use of coal from the Powder River Basin in Wyoming. According to the team, led by TeYu Chien at the University of Wyoming, while 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 a special chemical Pre-treatment of the coal. In their experiment, however, only the raw coal from the Powder River Basin was ground into powder. This powder was then placed on copper foil and sealed in glass containers with a gas mixture of argon and hydrogen before it was placed in a microwave oven. "By cutting the copper foil into a fork shape, the microwave radiation induced sparks that generated an extremely high temperature of more than 1,800 degrees Fahrenheit in a matter of seconds," said Chris Masi, lead author of the work, in a media release. The high temperatures then turned the carbon powder into polycrystalline graphite, with the copper foil and hydrogen gas also contributing to the process. The group - which includes researchers from New York, Nepal, and China - believes that this new method of coal conversion could be refined and carried out on a larger scale to achieve both higher quality and higher quantity of nano-graphite materials.