Discussion on appropriate coal slime reduction and dewatering technologies for use by coal sector

For realizing rational utilization of coal resources and achieving the coal slime reduction target, an analysis is made of the causes leading to the generation of coal slime. Based on the analysis made, various methods for reduction of the slime generated from the source by mining operations and during coal cleaning process are proposed. Analysis shows under the prerequisite that the incoming coal for cleaning is not over the limit in size and there is no possibility to block coal storage bunkers, increasing as much as possible the output of lump coal and avoiding ingress of dirt into raw coal are an ideal slime reduction approach; preremoval of fines from raw coal to be cleaned can reduce the amount of water in contact with the raw coal, a direct way for reduction of generation of slime; lesser spray water should be used during coal mining and transfer process for avoiding producing adverse effect on fine coal removal efficiency; for reducing the generation of secondary slime during coal cleaning process, the key lies in selection of coal cleaning process and equipment; for reduction and upgrading of coal slime, the flotation system needs to be used to have it thoroughly recovered, the flotation tailing product of coking coal plant should be directly blended with refuse product after dewatering for achieving the goal of reducing the output of slime, the power coal plant should make endeavor to recover the beneficiated product through flotation process for reduction of output of slime; in-depth dewatering of slime can be made with the use of technologically sophisticated ultrahigh-pressure filter press and the dewatered cake product can be sold after fine crushing and blending with clean coal; the percentage of breakage of gangue and the amount of water in contact with the gangue can also be reduced by adoption of wet and dry combined coal cleaning processes; there still exist some insufficiencies in slime reduction technologies, and for instance, the ultrahigh-pressure filtration technology needs to be continuously innovated for reducing the equipment cost while in the field of drying of slime, vigorous effect should be directed toward the development of clean and high-efficiency slime drying technology and reduction of the costs incurred.