Abstract:

There is considerable interest in developing new approaches to obtain washability data in coal preparation. The traditional “sink-float” method has been used for decades. Obtaining the data, however, is costly, and often the analysis time required is too long. Further, the dense liquids used to conduct the analysis can be problematic, on health and environmental grounds. The purpose of this paper is to describe a new method for conducting washability analysis, using fluidization. Although this method is used on coal particles smaller than 2 mm, the method may be applied to particles of any size or density. Although the process of fluidization is well established, its application to obtaining washability data appears to be novel. Narrow size fractions of the sample are obtained using conventional sieving. One of the narrow size frations is placed into the fluidized column, where it segregates readily producing a pressure profile, with the less dense particles at the top and the progressively denser particles below. The pressure profile of the suspension are removed from the vessel, the change in the suspension pressure profile measured, and the dry weight of the discharged sample determined. These data are then used to obtain the particle density