Analysis on separation effect in hydraulic classification

The recovery of coarse slime before coal froth flotation is one of the important processes in coal preparation plant. That affects the coal flotation size directly and affects the clean coal recovery, the clean coal ash content and the flotation agent consumption greatly. In this paper, the authors analyze the productive condition of a coarse slime recovery circuit in coal preparation plant A of a mining bureau in China. The coarse slime recovery system is composed of a settling cone, a desliming screen, a centrifuge and a hydrocyclone. The authors found that there is a fairly significant concentration effect during settling cone classification and hydrocyclone classification. This concentration effect has a bad effect on the coarse slime recovery. They also found the relations between the concentration effect and the slime size. The authors have developed a method to improve the coarse slime recovery circuit and have got good results.