On the improving the classification characteristics in a hydrocyclone through water injection

Abstract

In hydrocyclones, the particle separation efficiency is limited by the suspended fine particles, which are discharged with the coarse product in the underflow. It is well known that injecting water in the conical part of the cyclone reduces the fine particle fraction in the underflow. This paper presents a mathematical model that simulates the water injection in the conical part of apparatus. The model accounts for the fluid flow and the particle motion. The model includes: the turbulent particle diffusion and particle settling. Particle interactions, due to hindered settling caused by increased density and viscosity of the suspension, and fine particle entrainment by settling coarse particles are also included in the model. Water injection in the conical part of the hydrocyclone is performed in an experiment to reduce fine particle discharge in the underflow. This added water transports the fine particles of the sediment to the center, where they are directed to the overflow. The investigation of the influence of additional water injection in a classifier on the particle separation process characteristics has been performed on the basis of numerical modelling. It has been shown that the increase in water injection velocity leads to the increase of both the cut size and the minimal value of separation curve.