Continuous separation of fine particles in nonaqueous media in a lamella electrosettler

Abstract

In this paper, we describe the continuous operation of a lamella electrosettler and measurement of concentration profiles inside a lamella electrosettler to establish the existence of three sedimentation layers. This device was tested with a kerosene slurry containing fine alumina particles stabilized with a commercial surfactant, Aerosol OT. The measurement of concentration distribution of alumina particles inside the lamella electrosettler was made using our x-ray densitometer system. As a limiting case for low feed flow rates and low applied electric field strengths, a kinematic clear-fluid interface height formula was derived that describes the steady horizontal interface height as a function of angle of inclination, strength of applied electric field, and net clarified fluid overflow rate. A predictive hydrodynamic model of a continuous lamella electrosettler based on two-phase flow theory was developed and the experimentally obtained alumina concentration distributions were compared with the computed predictions of the hydrodynamic model. The computed variation in suspension layer concentration qualitatively agreed with the experimental measurements.