A method of increasing brown iron ore grade of beneficiation method comprising the steps of: 1. Grinding: The raw ore is ground into a ball mill to -200 mesh, accounting for 96% to 99%, and the pulp concentration is 50% to 60%. Then it is graded by a spiral classifier and enters the -200 mesh high-frequency vibrating screen. The concentration of the slurry after sieving is adjusted to 20% to 25%, and the unscreened ore is returned to the regrind; 2. Re-election: the above slurry is sent to the spiral chute for rough selection, selection and secondary selection; a. Rough selection: Desliming the slurry, the concentration of the slurry discharged from the concentrate and the middle mine is 15% to 25%, and enters the selection. The slime and part of the tailings of the spiral chute are discharged into the tailings pond. ; b. Selection: Desliming and selecting the slurry, intercepting the concentrate from the concentrate, and adjusting the concentration of the medium slurry discharged from the mine to 15% to 25%, entering the second selection, the outer edge of the spiral chute Sludge and part of tailings discharged into the tailings pond; c. Second selection: re-de-sludge and select the slurry, intercept the concentrate from the concentrate, and adjust the concentration of the medium slurry discharged from the mine to 15%~25% to enter the reverse flotation, spiral chute The outer margin of the slime and part of the tailings are discharged into the tailings pond; 3. Reverse flotation: Add 100g ~ 200g / t of inhibitor to the medium pulp after adjusting the concentration, 100g ~ 150g / t of the collector , stir for 2-3 minutes, under normal temperature, pH = 7 Flotation takes 10 to 12 minutes to obtain a high grade limonite concentrate. Glazed Tile Roll Forming Machine Ridge Cap Roll Forming Machine,Glazed Tile Roll Forming Machine,Encaustic Tile Cold Roll Forming Machine,Glazed Tile Roll Forming Production Line JINAN RAINTECH MACHINERY INDUSTRIES CO.,LTD , https://www.rollformingindustry.com