Concentration method for floatation tailings and concentration device

The invention discloses a concentration method for floatation tailings and a concentration device; the concentration method comprises the following steps: coal slime water enters a tailing thickener through a feeding tube; a flocculating agent is mixed in coal slime ash through a flocculating agent dosing tube which is communicated with the feeding tube; the coal slime ash mixed with the flocculating agent is concentrated and cleared in the tailing thickener; a flocculating agent dosing point is arranged at the front edge of the tailing thickener; before the flocculating agent is mixed in the coal slime ash, a coagulating agent is mixed in the coal slime ash by a coagulating agent dosing tube communicated with the feeding tube; a coagulating agent dosing point is arranged in front of the flocculating agent dosing point by L meter; L=10*(Q/X)/(3.14*R2*3600), wherein Q is coal slime water flow, the unit of which is m /h; X is the number of the feeding tubes; R is the radius of each feeding tube, the unit of whi