ABSTRACT
Dewatering is the separation of pulp into two parts, one is relatively solid-free and the other is relatively liquid-free, with respect to original pulp. The pulps containing fine sands and slimes, flotation pulps for example, are dewatered usually in the following three stages: sedimentation; filtration; and drying. Thickening is an operation of concentrating a relatively dilute slimy pulp into a thick pulp by allowing solid particles to settle under the influence of gravity force. In a thickener, the surface area must be large enough that the upward velocity of liquid is always lower than the settling velocity of the slowest-settling particle which is to be recovered. Filtration is the separation of finely divided solid particles from a fluid by driving the pulp to a membrane or septum, porous to the fluid but impervious to the solid, through which the fluid called filtrate passes.
