Effect of Particle Crowding at the Vortex Finder and Spigot on Dense Medium Cyclone Operation

This project addresses the priority of metallurgical efficiency improvements with respect to the operation of the Dense Medium Cyclone (DMC) and in particular the effect of crowding of the vortex finder and spigots on DMC operational efficiency. Coal preparation researchers and experts over the years have also identified that spigot and vortex finder crowding can be one of the major causes of lower than expected coarse coal recovery.

While this work has shown that the pilot plant data can be related to full scale plant data as evidenced by the plotted trends of the available literature data and the pilot plant data, it is clear that more work is required to quantify the relationships found more effectively. Some of the variables in the pilot plant experiments such as the cyclone pressure need to be controlled to a closer tolerance than the 3kPa achieved to remove this effect on the RD50 and Ep. It is also evident that more work is required at medium to coal (M:C) ratios in the region of 3 and below for both the spigot crowding experiments and the vortex finder experiments.

This work has shown the value of using RFID tracers in saving time and costs on full float sink analysis. The use of these RFID tracers also allowed for the experiments to be run in recirculation mode for extended times to build up the number of tracers reporting to the overflow and underflow. Each test was performed in duplicate to reduce the errors involved.