Underground coal separation process

An underground coal separation process adopting a water medium, comprising following steps:

• feeding an exploited raw coal into a Φ25 mm raw coal classifying screen by a raw coal feeding chute for screening to obtain a classifying screen oversize product with a particle size greater than 25 mm and a classifying screen undersize product with a particle size less than 25 mm;
• feeding the classifying screen oversize product with a particle size greater than 25 mm into a TDS intelligent dry separator to perform a dry coal preparation, and separating to respectively obtain a dry separation clean coal and a dry separation gangue to be discharged;
• feeding the classifying screen undersize product with a particle size less than 25 mm into a special underground compact jigging machine for separation to obtain a jigging machine overflow clean coal, a jigging middling coal and a jigging gangue, and directly discharging the jigging gangue;
• due to a high water content of the jigging machine overflow clean coal, feeding the jigging machine overflow clean coal into a fixed screen for predewatering to obtain a clean coal fixed screen oversize product and an undersize water which is Φ1 mm clean coal fixed screen undersize water, feeding the undersize water into a first coal slime pool, feeding the clean coal fixed screen oversize product into a Φ13 mm classifying screen for screening to obtain an oversize block clean coal with a particle size greater than 13 mm and an undersize clean coal with a particle size less than 13 mm, discharging the oversize block clean coal with a particle size greater than 13 mm serving as a clean coal product, feeding the undersize clean coal with a particle size less than 13 mm into a clean coal centrifugal dewatering machine for dewatering to obtain a centrifugal dewatering machine clean coal and a first centrifugate, discharging the centrifugal dewatering machine clean coal serving as a clean coal product, and feeding the first centrifugate into the first coal slime pool;
• feeding the jigging middling coal into a Φ13 mm classifying screen for separation to obtain oversize middling coal with a particle size greater than 13 mm and undersize middling coal with a particle size less than 13 mm, discharging the oversize middling coal with a particle size greater than 13 mm directly serving as a middling coal product without further dewatering, feeding the undersize middling coal with a particle size less than 13 mm into a middling coal centrifugal dewatering machine for dewatering to obtain a dewatered middling coal and a second centrifugate, discharging the dewatered middling coal serving as a middling coal product, and feeding the second centrifugate into the first coal slime pool;
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• mixing the undersize water, the first centrifugate and the second centrifugate in the first coal slime pool to form a to-be-separated coal slime water containing coarse coal slime, feeding the to-be-separated coal slime water containing coarse coal slime into a water medium classifying and separation cyclone by a slurry pump, after separation, performing a first-section classification by the water medium classifying and separation cyclone to obtain an overflow, enabling cyclone a first-section underflow to enter a second-section separation to obtain an overflow containing coarse clean coal slime and an underflow containing coarse middling coal slime, feeding the overflow into a stirring barrel for stirring, adding a coal slime water treatment medicament which is a sedimentation-promoting medicament into the stirring barrel by a medicament adding box, completely mixing the overflow and the coal slime water treatment medicament in the stirring barrel to obtain coal slime water, feeding the coal slime water into a roadway high-efficiency concentrator to perform sedimentation, discharging a concentrator underflow from an outlet at the bottom of the roadway high-efficiency concentrator after sedimentation, feeding the concentrator underflow into a coal slime filter press to perform filter pressing and dewatering to respectively discharge a coal slime and a filter press filtrate, discharging the filter press filtrate into a clarifying pool, discharging a concentrator overflow from an outlet above the concentrator and feeding the concentrator overflow into the clarifying pool;
• feeding the overflow containing coarse clean coal slime into a coarse clean coal sieve bend for screening and feeding the underflow containing coarse middling coal slime into a coarse middling coal sieve bend for screening to generate a coarse clean coal sieve bend undersize water and a coarse middling coal sieve bend undersize water respectively, feeding the coarse clean coal sieve bend undersize water and the coarse middling coal sieve bend undersize water into the first coal slime pool again, feeding the coarse clean coal sieve bend oversize product of the coarse clean coal sieve bend and a coarse middling coal sieve bend oversize product of the coarse middling coal sieve bend into a coarse clean coal slime centrifugal dewatering machine and a coarse middling coal slime centrifugal dewatering machine respectively for dewatering to finally generate a coarse clean coal slime, a coarse middling coal slime, a third centrifugate and a fourth centrifugate, and feeding the third centrifugate and the fourth centrifugate into the first coal slime pool to continuously circulate.