Process of coarse coal slime back washing in pre-desliming dense medium cyclone sorting

Abstract

The invention discloses a process of coarse coal slime back washing in pre-desliming dense medium cyclone sorting. Pre-desliming is carried out on raw coal fed to be washed to obtain plus sieve raw coal and minus sieve coal slime water, and the plus sieve raw coal enters a dense medium cyclone directly to be sorted; hydraulic cyclone grading is carried out on the minus sieve coal slime water to obtain coarse coal slime and fine coal slime; the coarse coal slime is dehydrated and then fed into the dense medium cyclone again to be sorted; the fine coal slime enters a coal slime water system of the next procedure to be recovered and floated. By the utilization of the advantage that the sorting minimum of the dense medium cyclone is smaller than 0.25 mm, the coarse coal slime obtained after desliming is fed into the dense medium cyclone again to be sorted, so that the flow path is simplified, a set of conventional sorting equipment is omitted, a high-level and high-benefit production system with the non-pressure feeding three-product dense medium cyclone as the main washing equipment is formed, and equipment investment is lowered. Particularly, if the raw coal fed to be washed contains batt, coal slime is seriously slimed, conventional coarse coal slime sorting equipment is low in sorting index, and the process is high in sorting index and can meet process requirements.

Description

technical field [0001] The invention relates to the technical field of coal washing, in particular to a process for rewashing coarse coal slime in pre-delimed heavy medium cyclone sorting. Background technique [0002] Due to poor coal seam occurrence conditions, the roof and floor are relatively easy to break, and the raw coal properties are greatly different. At the same time, with the improvement of the degree of coal mining mechanization and the proportion of raw coal washing, the output of coal slime will increase greatly. In the coal preparation design, the combined process of pre-desliming dense medium cyclone separation + coarse slime separation (and fine slime flotation) is widely used. In order to ensure the desliming effect, the mesh size of the desliming screen is generally taken as 1 -2mm. The slime water after desliming is hydraulically classified first, then the coarse slime (1.0-0.3mm or 2.0-0.3mm) is sorted separately, and the fine slime (<0.3mm) is ...

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Problems solved by technology

All these conventional sorting methods need to purchase a set of sorting equipment, which increases the cost, and the process is relatively complicated, and the process indicators will be affected by factors such as the concentration of the feed, the amount of cla

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