Comparative Study on the use of Filter aids for Reducing the Resistance in Vacuum and Pressure Filters

Abstract

The objective of the present work is to investigate the effect of filter aid on specific cake resistance and filter medium resistance for filtration of slurry in vacuum leaf filter and plate and frame filter press. Homogeneous suspension of calcium carbonate was used as feed slurry for all experimental runs. Perlite and diatomite were used as filter aid at 0.2, 0.4, 0.6, and 0.8 % concentrations (one filter aid at a time) for the filtration of 2, 3 and 4 percent calcium carbonate slurry as body feed. It was observed that the use of filter aid was effective in minimizing the specific cake resistance at lower initial concentration of the slurry. The resistance, particularly the specific cake resistance, was found to decreases with increase in concentration of the filter aid for both perlite and diatomite. From the results obtained, it is clear that the resistance for filtration is reduced to a considerable extent by the use of filter aid which in turn would reduce the total power consumption for filtration.