A preliminary study of the technology for classification and upgrading of washed coking coal middlings

In order to tap the potential for better utilization of scarce coking coal resources, the washed coking coal middlings product of Xiqu Coal washery, Shanxi Province is selected as the object of study, and treated using the mechanical impact pulverization-classification-upgrading technology, so as to investigate the variation of ash, yield and size of each graded product under different operating conditions. Result of test indicates that under different operating parameters, the ash and size of all the products from slag to filter product tend to decrease in turn, and the speed and air inlet volume of the classifier exert a great influence on the yield of products. The optimum parameters obtained through single-factor experiment are as follows: speed of pulverizer －2 600 r/min; speed of classifier －800 r/min; air intake －0.5 m³/min. The minimum ash content of graded products is 29.54%, 12.3% lower than that of raw coal, and the d₉₀ of filter product is around 30 μm, well demonstrating the effectiveness of the classification and upgrading integrated technology.