It is particularly effective in cleaning very fine coal, smaller than grains of sand, that are too small to be cleaned by conventional processes and, as a result, are often discarded. Developed in a joint program with the U.S. Department of Energy in the 1980s, the Microcel' technology is now used at commercial coal-cleaning installations in several states. Internationally, the Peak Downs Mine in Australia has just signed a contract to install 16 Microcel' units, the largest number at one site anywhere in the world. Yoon gave a series of lectures to different groups of engineers in the coal fields in Australia last summer, which may have helped market the technology in that country. The People's Republic of China, the country with the world's largest production, just purchased six Microcel' units.
Agreements are in place for coal cleaning plants in India and Poland as well.
Although the technology was developed originally for coal, the technology is also being used for processing different minerals. While the technology is successful commercially. Yoon is most excited about his involvement in basic research. As a result of many publications on this topic, his contributions are recognized in the community of colloid chemists. Yoon earned his bachelor's degree from Seoul National University in mining engineering.