Development of the air-sparged hydrocyclone for froth flotation in a centrifugal field

The potential of air-sparged hydrocyclone flotation technology for the efficient separation of fine particles was investigated. Air-sparged hydrocyclone flotation is a new particle separation technology that has been under development at the University of Utah laboratories during the past decade. This technology combines froth flotation principles with the flow characteristics of a hydrocyclone such that the air-sparged hydrocyclone system can perform flotation separations in a matter of less than a second. This feature provides the air-sparged hydrocyclone with a high specific capacity, 100 to 600 times greater than the specific capacity of conventional flotation machines or flotation columns.; During the past decade significant progress has been made in the development of air-sparged hydrocyclone (ASH) flotation technology. From the fundamental side, improved understanding of the complex multiphase flow has been achieved based upon preliminary measurements by x-ray computed tomography for density gradient analysis, and from high-speed video photography for bubble formation. While from the practical side, pilot plant testing with a 2-inch diameter ASH system has been successful in a number of applications. Some recent efforts at dimensionless analysis of system variables for fine coal seem to provide additional insight for the effective utilization of the ASH technology. Finally preliminary scale-up considerations indicate that scale-up to larger diameter air-sparged hydrocyclone units would result in increased clean coal yield, reduced reagent consumption and extension of the upper particle flotation size limit.; It has been concluded that the air-sparged hydrocyclone has a tremendous potential to significantly alter conventional flotation technology. In this regard, it is strongly recommended that additional pilot-scale test programs should be planned for larger diameter units to establish scale-up relationships and wear characteristics of the porous tube. In addition, investigation of the multiphase fluid flow behavior by x-ray computed tomography should be undertaken to determine in further detail fundamental aspects of air-sparged hydrocyclone flotation.