Beneficiation method for extremely lean iron ore pre-separation tailings

The invention discloses a beneficiation method for extremely lean iron ore pre-separation tailings, and belongs to the technical field of mineral processing. The method comprises the following step: (1) smashing extremely lean iron ore pre-separation tailings, and grinding; (2) performing low intensity magnetic separation and high intensity magnetic separation, and combining strong magnetic concentrate and weak magnetic concentrate into mixed coarse ore; (3) filtering the mixed coarse ore, heating the mixed coarse ore to 580-700 DEG C, preserving heat for 20-120 seconds, putting the mixed coarse ore under a reducing atmosphere condition for preserving heat for 3-60 minutes, and cooling in the air to a temperature below 50 DEG C; (4) adding water to prepare ore pulp, stirring and performing pre-separation; (5) finely grinding, performing concentration, and filtering water from concentrate. According to the method, the high intensity magnetic separation and low intensity magnetic separation, calcination and reduction, and pre-separation-grinding and concentration are performed to obtain a product of which the iron grade is larger than 60 percent. The product has a stable index and high economical performance, and resources can be effectively utilized.