POC-SCALE TESTING OF A DRY TRIBOELECTROSTATIC SEPARATOR FOR FINE COAL CLEANING

During the past quarter, several modifications were made to the TES unit and the materials handling system. The cylindrical electrodes were replaced by a set of screen electrodes to provide a more uniform electrostatic field. The problem with the recycle conveyor neutralizing the particle charge was also corrected by replacing it with a bucket elevator. In addition, problems with the turbocharger were corrected by increasing the number of charging stages from one to two. These modifications have significantly improved the separation performance and have permitted the POC-scale unit to achieve results in line with those obtained by the bench-scale separator. The testing phase of the project was continued at a rapid pace during this quarter. The test work showed that the modifications to the TES unit and the reduction in feed size from 28 mesh to 35 mesh resulted in significant overall improvement in yield and combustible recovery compared to the data reported in the last quarter. At that time, there was a significant discrepancy between the bench-scale and the pilot-scale results. The pilot-scale test work is now approaching the bench scale test results. However, further pilot-scale test work is required to further improve the results and duplicate the bench-scale test work