Experimental study on the feasibility of rewashing of middlings using pressure-fed 3-stage heavy medium cyclone

In coal washing with 3-product H.M. cyclone, its middlings product is found to have misplaced clean coal. To tackle this problem, a pressure-fed 3-stage H.M. cyclone for rewashing the middlings is designed based on the experience in the design of the traditional 2-stage 3-product version. Tests are made with the 2-stage 3-product and the 3-stage H.M. cyclones through operation with medium for making a comparison of the density variation and difference at their individual outlets. The test result well demonstrates the feasibility of making rewashing of middlings with the use of the 3-stage heavy medium cyclone.