Effect of Solid Concentration on Settling of Unflocculated Iron ore Slimes in Compression Zone

Abstract

The settling behaviour of iron ore (slimes) particles in the compression zone is presented here. The compression zone is characterized by a sharp liquid/suspension inter-face. Plug type flow of the particles prevails in this zone. The start of compression zone, which follows the constant settling rate zone, is a function of settling period and initial solid concentration of slurry. For a very dilute solution, the compression zone is absent and the particles settle with maximum and constant sedimentation rate, whereas, for a concentrated slurry the compression zone starts earlier (when compared to the total duration of the particle settling In this case). The data reveal that solid concentration of the suspension has considerable effect on the settling kinetics. The settling rate Is significantly decreased in thecompression zone when compared to the Initial settling rate zone. The settling data in this zone follow the first order kinetics, i.e. the rate of descent of the supernatant / suspension Interface is proportional to the height of the suspension. The rate constant is a linear function of solid concentration In this case. The experimental results have been formulated to derive a model.