Abstract:
To address the problems associated with conventional coarse coal slime recovery processes, including high ash content of recovered clean coal slime, excessive coarse particle carryover, low recovery, fine particles entrained in the screen oversize, and coarse particles reporting to the screen undersize, Fucun Coal Preparation Plant conducted an application study of a new process. A three-mass electromagnetic stack screen was adopted to replace the existing stack screen and linear dewatering screen, forming a new combined process consisting of “a conical inclined-plate settler + classification hydrocyclone + three-mass electromagnetic stack screen + coal slime centrifuge”. System capacity expansion and pipeline optimization were also implemented to upgrade the coarse coal slime recovery system. The effectiveness of the modification was evaluated by comparing the particle size distribution and ash content of various products before and after the modification.After the modification, the ash content of the recovered coarse clean coal slime decreased by 2.63 percentage points. The quantity of coarse particles larger than 0.25 mm reporting to the overflow was reduced, the amount of material entering flotation decreased by 20%, and flotation reagent consumption decreased by 39%. Meanwhile, the overall clean coal yield increased by 0.23 percentage points, generating approximately 7.06 million yuan in additional annual revenue and cost savings. The optimization and simplification of the coarse coal slime recovery process significantly reduced operating costs, while ensuring the ash and moisture contents of the recovered coarse clean coal slime and substantially improving the overall clean coal yield. The modification achieved the objectives of reducing costs and operational burden while improving product quality and economic efficiency. This technical approach can provide a reference for the optimization of coarse coal slime recovery processes in similar coal preparation plants.