Abstract
The osmotic dewatering of slurry was investigated using polyethylene glycol solution and bentonite slurry. After bentonite slurry was enclosed in a dialysis membrane tube (MWCO 1,000), the tube was submerged into polyethylene glycol solution (MW 10,000) until the equilibrium of dewatering. It was revealed that dewatering process was divided into filtration and consolidation processes. The dynamic behaviors of the filtration process were well analyzed by the Ruth filtration rate equation. It was clarified that a highly compressible filter cake formed in the tube. Also, the dynamic behaviors of the consolidation process could be evaluated on the basis of the modified Terzaghi model. The variations over time of the average consolidation ratio were well described by the fitting method. Moreover, as a result of dewatering of bentonite slurry by mechanical pressure, it was found that the osmotic dewatering behavior was similar to the mechanical dewatering behavior. This indicates that the role of the osmotic pressure is in agreement with that of the mechanical pressure.
