KEPRI is conducting a project for the separation of unburned carbon from fly ash with an objective of constructing a 30t/h commercial plant. To develop a separation scheme, fly ashes were collected from various power plants and analyzed for their physical characteristics. It was found that coarse fly particles were carbon rich and removal of these particles from bulk fly ash could reduce the LOI content to less than 3% at a yield over 70%. For this purpose, a sepecial type of cyclone with guide vanes was built to separate the coarse fly ash particles. Test results showed that a sample of fly ash with 6.0% LOI could be processed into a product containing 3.0% LOI. Generally though, the results were not as good as expected due to the inefficent size saparation and more importantly due to the break-up of the coarse carbon rich particles. Therefore, an additional measure is being taken to enhance the separation by incorporating the electrostatic forces.