USE OF CONTINUOUS-FLOW CENTRIFUGATION TECHNIQUES FOR COAL MACERAL SEPARATION .1. FUNDAMENTALS

The utility of continuous flow centrifugation (CFC) for the separation of coal macerals was investigated. From a systematic study of the various factors affecting the efficiency of the separation, a methodology was developed for routine separations. Using CsCl/Brij-35 as the separation media, maceral enrichments of greater than 85 % could be easily achieved for coals with a particle size of <10-mu-m. In addition, analyzing the separated CFC phases by density gradient techniques provided detailed insight into the separation process. This process could be modeled using simple dynamics. One consequence of this modeling was to show that the purity of a sink/float type separation is not constant but will vary with the separation density. The behavior of the phase purities is intimately tied to the density distribution of the coal.