Since the 1980s, Yoon, a member of the a National Academy of Engineering, and his colleagues in Virginia Tech’s College of Engineering have developed various advanced separation processes for the minerals and coal industries, including microbubble flotation, dewatering aids, hyberbaric centrifuge and hydrophobic-hydrophilic separation (HHS).

The first three have been commercialized, and the last will soon be tested at a pilot scale, an essential step before commercialization.

“With this new technology, with a patent pending, the industry will be able to recover the ultrafine coal that was previously thought to be unrecoverable,” Yoon said. This development also means less coal will be lost to the environment and it will help companies’ finances, he added.

For Yoon, his life’s work started after he learned in a high school chemistry class how detergents remove dirt from clothes. He was hooked on the “why factor.” He took his fascination with bubbles, and in the 1980s developed the microbubble flotation process, a term he coined to advocate the use of small air bubbles to separate fine coal from mineral matter and recover the valuable energy resource better.

He secured research funding from the U.S. Department of Energy and the Virginia Center for Innovative Technology to develop and patent the microbubble flotation process, which has been marketed commercially under the name Microcel. The coal industry regards it as one of the best technologies separating fine particles.

During the last 15 years or more, Yoon and his colleagues have also been developing advanced technologies for separating water from fine coal.