Multistep centrifugal consolidation method for characterization of filterability of aggregated concentrated suspensions

Current development of analytical centrifugation methods facilitates the experimental characterization of dispersion stability and optimization of separation processes (such as centrifugation and filtration). Nevertheless, theoretical analysis of the centrifugal data remains rather complex. In addition, different side effects can influence the centrifugal process and complicate data interpretation. The present paper proposes a simple method for characterization of filterability of concentrated aggregated suspensions by centrifugal consolidation. Different experimental protocols were tested in order to reduce the influence of side effects. Selection of the optimal protocol was based on X-ray analysis of local (spatially resolved) consolidated sample structure. The multistep centrifugal consolidation with constant centrifugal acceleration ratio is suggested. Data analysis based on a single numerical solution of a basic consolidation equation yields the pressure dependency of specific cake resistance. A satisfactory correspondence (15% difference) was observed between the pressure dependency of specific cake resistance determined from the proposed multistep centrifugal consolidation, and conventional constant pressure dead-end filtration experiments for the studied concentrated aggregated kaolin suspension in the pressure range of 7.5…170 kPa.