Author:

Abstract:

Flotation coal with 10-18% ash has been dewatered to moisture contents of around 20% in two continuous pressure filters of 60 m SUP 2 each at a rate of approximately 1 ton dry weight per m SUP 2 per hour. Performance data are presented and compared with off line filtration data obtained in a small test filter. A theoretical model is presented which combines a Kozeny-Carman approach with a Rosin-Rammler type description of the particle size distribution. The model allows the priori prediction of cake permeability and filtration time or cake thickness on the basis of a measured particle size distribution. The predicted values compare well with the observed values for both the industrial and test filters, if it is assumed that in filtration of slurries with a wide size distribution, the filter cake will normally display axial layering to a greater or lesser extent. Preliminary experimental support is presented for this assumption. (A)