The invention discloses an improved rake thickener for mineral separation. The improved rake thickener comprises a central swing mechanism and a bridge frame. The central swing mechanism is fixedly arranged at the center of a concentration tank, the inner end of the bridge frame is connected with the central swing mechanism, a chain wheel driving device is arranged at the outer end of the bridge frame, an overflow groove is formed in the inner side of an outer ring track of the concentration tank, the central swing mechanism comprises a fixed support, a rotary support, a plane bearing, a central turntable, a current collector and a sliding ring, and the center of the central swing mechanism is sleeved with an ore inlet pipeline. The fixed support is fixedly arranged on a cement brace at the center of the concentration tank, the rotary support is arranged above the fixed support, and the plane bearing is arranged between the bottom of the rotary support and the upper surface of the fixed support. The central turntable is arranged at the upper portion of the rotary support, the current collector is fixedly arranged at the upper portion of the central turntable, the sliding ring is fixedly arranged on the ore inlet pipeline, and the current collector is connected with the sliding ring in a mutual sliding contact mode. An automatic overflow groove cleaning device is arranged on the overflow groove.