Coal Cleaning using Dense Medium Cyclone and SpiralPerformance

Dense medium cyclones and spiral concentrators are the most prominent coal cleaning technologies used worldwide. Dense medium cyclones provide the most efficient separation performance when treating particles as coarse as 75mm to sizes as small as 1mm. Spiral concentrators are known to provide an effective separation performance at relatively low cost for the 1 x 0.15 mm particle size range. The project will evaluate the performance of the two technologies when applied to the cleaning of Korean anthracite coal. The test program will involve the use of a dense medium cyclone circuit existing in the University of Kentucky minerals processing laboratory which consists of a 150mm diameter cyclone, pump and sump. The system is operated in closed-circuit with the product and tailing streams being recycled to the feed sump. Korean coal that is sized to 6 x 1mm will be used in the test. A parametric test program will be conducted to evaluate the effects of medium density, medium-to-coal ratio and apex diameter on separation performance. The results will be used to develop empirical models that will assist in identifying the optimum separation conditions. Additional experiments will be performed to verify the optimum performance. Samples collected under the optimum conditions will be subjected to density fractionation to allow assessment of the process efficiency parameters including probable error, bypass and organic efficiency. The spiral concentrator performance will also be evaluated in a closed circuit using a standard compound spiral that is commonly utilized in operating coal preparation plants today. The tests will focus on the treatment of 1 x 0.15 mm Korean coal in a slurry form. Parameters to be evaluated include feed volumetric flow rate, feed solids concentration and the product splitter position. The process efficiency will be measured in the same manner described for the dense medium cyclone evaluation.