Determining Capillary Pressure Curve Parameters for Flocculated Fine Coal

Abstract This paper describes the determination of capillary pressure curves on flocculated fine coal filter cakes, which to the best of our knowledge, has not been reported before. The objective was to derive values of pore size distribution index (λ) and breakthrough pressure (pb) which could then be incorporated into a model for predicting the desaturation kinetics of vacuum filtration. The need to model the vacuum filtration of flocculated systems is important owing to the widespread use of polymer flocculants in fine coat filtration in Australian coal preparation plants The determination of the capillary pressure curves in the presence of the flocculant was surprisingly difficult since the polymer flocculant molecules blinded the fine pores of the filter medium. The problems were solved by measuring pseudo-capillary pressure curves. Values of λ and pb, were determined for the flocculated systems of 0.65 arid 5.5 kPa respectively, compared to 0.56 and 13.5 kPa for the unflocculaied cakes. The data wer...