Analysis of consolidation process in filter cake dewatering by use of difficult-to-filter slurries.

Filter cakes can be dewatered effectively by use of bentonite slurry, which is very difficult to filter, to cover the cake surface at the end of filtration. This dewatering method has the advantage of using air pressure to compress filter cake, so that a large amount of cake is easily deliquored. In the previous paper, on the assumption that the amount of permeated water from the bentonite cake was negligible, the consolidation effect was investigated on the basis of the conventional expression equations. In this paper, in order to examine both the internal mechanism and the overall characteristics of the compressed cakes under dewatering, a rigorous analysis is developed in which the effects of water permeation from the bentonite cake are taken into account. Predictions using the present analysis are shown to be in good agreement with experimental results of the hydraulic pressure distributions in the compressed cake and the average consolidation ratio.