FILTRATION CHARACTERISTICS AND CAKE PROPE RTIES IN MICROFILTRATION OFBINARY-MIXTURES OF FINE PARTICLES

Variations of the filtration rate with time and the properties of the filter cake were examined for microfiltration of binary mixtures of fi ne particles. Both the average porosity and the average specific filtr ation resistance were determined from filtration experiments in which a filter was subjected to a sudden reduction in its filtration area. T he average porosity in the filter cake of the binary mixtures of fine particles was explained well by the mixture packing model in which sma ll particles fill the voids between large particles. The decrease in t he ratio r of small to large particle size caused a significant increa se in the value of beta, which is a measure of the mixing action betwe en large and small particles. In addition, the average specific filtra tion resistance of the binary mixtures was obtained on the basis of th e additive law of the effective specific surface area. The filtration rate in the binary mixtures was evaluated accurately by using both the average porosity and the average specific filtration resistance.