The Role of Filter Medium in Filtration

초록

To know the role of the filter medium in filtration, an experimental technique named filtration-permeation was applied to the filtrations of calcium carbonate suspension with various filter media, which are usually being used in laboratory, having the range of equivalent pore diameter from 0.43 ㎛ to 4.26 ㎛. The average specific cake resistances with filter media of comparatively large pore diameter, i.e. 2.2 ㎛ to 4.2 ㎛, do not give the wide variation in measured values. The filter media of small pore diameters, 0.43 ㎛ and 0.51 ㎛, give almost the same measured values of average specific resistances. But the filter media which have the pore diameter of 0.95 ㎛ and 1.2 ㎛ gives much higher average specific resistances up to three times. This means that the filtration time could be prolonged much more with inadequate filter medium, and the average specific resistance measured with these media do not represent that of the industrial practice. The analysis of the data during permeation period gives the conclusion that above phenomenon is originated from fine particle migration through filter medium and/or cake and the clogging of them. .