Energy requirement of suspension dewatering

Abstract

This work estimated the energy required to dewater a clay suspension, considering the total energy input received by the suspension from the dewatering device, the bond strength between adjacent water and solid surface, and the intra-cake friction loss. The centrifugal dewatering and consolidation dewatering were the testing means, and a UK ball clay suspension coagulated with alum was the testing sample. At the initial stage of centrifugal dewatering, most energy input was used to overcome process irreversibilities other than intra-cake friction, giving low-energy efficiency. To rotate faster or to flocculate at optimal dose needed more energy to dewater. On consolidation, most input energy was consumed to break down the bond strength to a critical residual water content, beyond which the friction loss became dominant. The methods presented herein provided a quantitative index to evaluate the efficiency of real dewatering process from an "ideal" dewatering system. Copyright ? Taylor & Francis, Inc.