Wide-size-fraction flotation system and process

A wide size fraction flotation process for coal washing and ash removal, comprising the following steps:

• in step 1:
• feeding coal slime to be floated into an agitator, adding water into the agitator, agitating and mixing the floating coal slime with the water to a homogeneous state, and feeding the mixture into a classifying cyclone by a first feeding pump for pre-classifying;
• in step 2:
• after the coal slime is classified in the classifying cyclone, feeding the overflow from the classifying cyclone into a flotation column by a second feeding pump for flotation, discharging the flotation tailings through an underflow port of the flotation column, while collecting the flotation concentrate through an overflow port of the flotation column and feeding the collected flotation concentrate into a bubble generator by a fourth feeding pump, and feeding the flotation concentrate into a hydraulic flotation machine through the bottom of the hydraulic flotation machine via the bubble generator;
• and
• in step 3:
• after the coal slime is classified in the classifying cyclone, feeding the underflow in the classifying cyclone into a hydraulic flotation machine by a third feeding pump for recovery by flotation.