Abstract
The objective of this study was to develop a better understanding of the effects of operational parameters of decanter centrifugation, such as dry solid ratio (DS), sigma value (Σ), and volumetric flow rate of feed (Qfeed), on separation performance, especially corrected cut size (D50C) and particle recovery to underflow (EUF), with regard to separating a fine-grained fraction from soil slurry. The sigma value (Σ) represented the area of a settling tank capable of the same separation performance in the gravitational field.
As a result of this study, following observations were made; 1) the values of EUF declined in a linear fashion with Qfeed/Σ, 2) the corrected cut sizes (D50C) increased in proportion to Qfeed/Σ, 3) the value of EUF declined in a linear fashion with D50C, 4) D50C obtained through this experimental study differed significantly from the theoretical values calculated on the basis of the sigma values by assuming free settling. It was inferred that (a) centrifugal separation performance was strongly influenced by hindered settling even if feed slurry was relatively low concentration (11-20%DS), and (b) the smaller the grain size, the larger its percentage of platy and cylindrical particles.
