Hydrocyclones have widespread use as classifiers in applications such as
mine fill preparation and coal preparation. A fundamental conflict often
exists between recovery of all of the valuable material and maintaining
the quality of the product. This conflict is a result of a portion of the feed
material passing through the cyclone, effectively without undergoing any
classification. This paper describes an investigation, undertaken as an undergraduate
project in mining engineering at the University of NSW (Brook, 1994),
into aspects of cyclones in which supplementary water injection is used in
an attempt to reduce the amount of misplaced fine material reporting to
the coarse product and hence improve the overall classification efficiency.
In particular, the study concentrated on the effects of different modes of
water injection. Two methods of introducing wash water into the cyclone body were
investigated. A series of tests were performed on a laboratory
hydrocyclone having provision for radial water injection at different
levels through small orifices in the wall of the conical section, and a
preliminary study was made of the performance of a novel cyclone in
which the conical section had walls of a permeable polyethylene,
permitting a uniform introduction of wash water over the entire surface.