Bimodal dense medium for fine particles separation in a dense medium cyclone

摘要

The present invention provides a method for separation of fine particles in a bimodal (two component) dense medium. In accordance with the present invention, the dense medium comprises ferromagnetic particles that have a relative density range from about 4.0 to 7.0 suspended in water and are characterized by a bimodal size distribution. Such a medium exhibits high stability and favourable rheological properties. The use of such a bimodal magnetite dense medium in cleaning fine coal in a dense medium cyclone or dynamic dense medium separator results in optimum separation efficiency when the medium contains approximately 20-40% fine and 60-80% coarse magnetite, and when the size ratio of coarse-to-fine magnetite is in the range of 5 to 10.