Interrupted electroosmotic dewatering of clay suspensions

Abstract

A new method of electroosomotic dewatering with interrupted DC voltage or current was demonstrated. In this method the electrodes are short circuited during the periods of power interruption. Suspensions of Bentonite, kaolin and red clay were dewatered by electroosmotic dewatering using interruption with a short circuit, interruption with an open circuit and continuous DC. The suspension was held in a vertical 5-cm diameter column between two platinum-coated, titanium mesh electrodes, an upper anode, and a lower cathode. In the interrupted regimes the off-time ranged from 0.5–20 s with the on-time fixed at 30 s. The interrupted process with a short circuit was also applied at the end of a DC run when dewatering had stopped. Interruption with a short circuit applied during a 0.5 s off-time removed 20–40% more water than DC or interruption with an open circuit for equal energy consumption. Interruption with a short circuit at the end of a DC run removed additional water, but the total removal was less than if interruption with a short circuit were applied from the beginning.