Application of the reflux classifier for measuring gravity recoverable product

The characterisation of fine particles by size and density is fundamental to the design of mineral beneficiation plant and to modelling the separation achievable by a given technology. In the minerals industry this information is often limited to relatively low densities, or simply neglected and hence a laboratory scale trial of a given technology is invariably used. Often this assessment is only conducted over a limited range of product grade, and therefore the full grade-recovery relationship remains unknown. Further, in the absence of a bench-mark level of separation, it is difficult to assess the true performance of the equipment. The present paper outlines a novel method for measuring the gravity recoverable product from a given feed. The Reflux Classifier, a new separation technology, can be used in the laboratory under semi-batch conditions to achieve a form of flow fractionation. Combined with size fractionation, the method provides a basis for producing a close approach to the true grade recovery curve over the full range. A number of case studies are examined, and the underlying basis for the flow fractionation outlined with reference to the system hydrodynamics.