Abstract: The process study and production process reformation of dry pre-discarding tailings of medium crushing production were conducted aiming at the problems of the low grade of feeding， high concentration ratio， high processing cost and long-term overload operation of the tailing thickener in Heshangqiao concentrator. The results showed that: ① After the pre-discarding tailing with magnetic pulley of CTDG1220 type for on site medium crushing production， the tailing containing 10.31% TFe and 0.80% mFe can be discarded with a yield of 12.38%， and the concentrate containing 20.00% TFe and 7.29% mFe can be obtained with a TFe recovery rate of 93.21% and a mFe recovery rate of 98.42%. The grade of the final cocentrate is 1.20 percent point higher in the later operation. ② The load of the fine crushing and subsequent system can be reduced significantly， which is beneficial to the stable operation of the subsequent system. In addition， 0.742 8 million tons waste rock can be sold as sandstone aggregate every year. ③ The annual revenue generated by additional system can reach 37.28 million yuan.

Key words: Magnetite, Dry pre-discarding tailings of large rock, Magnetic pulley, Sandstone aggregate, Economic benefit