Experimental Study on Batchwise Centrifugal Filtration

Batchwise centrifugal filtration process of limestone^- and coal-water slurries were experimentally investigated by using the method of stroboscopic photography, instead of the conventional method to measure the volume of filtrate. By means of this method, the relation between filtrate volume and time was exactly determined and the centrifugal sedimentation process of particles was examined in detail. The particle settling had to be taken into account the centrifugal filtration process. It was demonstrated that the cake volume predicted on the basis of filtrate volume was largely different from the true value, and consequently the specific filtration resistance could not be determined as a characteristic value of the cake. Thus, the rate equation of cake formation was derived taking into account the particle setting. And then it was approximated to simplify the subsequent calculating procedure. By using this equation and the experimental data, the true values of average specific resistance were calculated and the batchwise centrifugal filtration process was predicted in the course of time. The process calculated by the approximated method, which proposed in this paper, was favourably consistent with the experimental course. In addition to the conclusion, the process predicted by the precise filtration theory, which was in need of the compression-permeability data and a trial and error calculating method, showed fairly coincidence with the experimental results.