Technical Note

A new approach to the nominal rotation frequency and capacity of roll and drum separators

E.Th. Stamboliadis*

Technical University of Crete 73100 Chania, Greece

Accepted 5 April 2005


Roll or drum separators are used in mineral processing especially for magnetic or electrostatic separation. Industrial and laboratory experience has shown that the separation efficiency depends on the size of the rotating cylinder, the particle size, the field strength, the susceptibility of the material, the rotation frequency and the feed rate. The rotation frequency and the feed rate are usually controlled empirically in order to obtain best separation efficiency at the maximum possible capacity. Given the number of parameters involved in determining the optimum capacity the question is, whether there is any capacity based on the geometry of the cylinder and particle size that can be defined as the nominal or designed capacity, regardless the type of the material to be processed. This paper introduces the concept of nominal rotation frequency and defines a nominal capacity that depends on the cylinder radius and the particle size. This is achieved by taking into consideration, the radius and rotation frequency of the cylindrical separator, the laws of physics that determine the free motion of particles in a gravitational field and the particle size. The strength of the applied field and the susceptibility of the material are not required for this approach.

Keywords: Nominal rotation frequency, Nominal capacity, Magnetic separator, Electrostatic separator, Roll separator, Drum separator

* Corresponding author
   E-mail : elistach@mred.tuc.gr