Abstract: The content of P2O5 in iron beneficiation tailings of a mine is 2.57%. The process of iron removal by high intensity magnetic separation-desulfurization by reverse flotation-degypsum by reverse flo⁃ tation-apatite by direct flotation is adopted.In order to solve the problem of high cost of flotation reagents， the effects of fatty acid chain length，unsaturation，hydroxyl introduced into the structure and the amount and ratio of combined fatty acids on the flotation of apatite，ankerite and anhydrite are explored.The results show that when the mass ratio of sodium laurate to sodium oleate is 6∶4，the floatability of apatite is the best. Under the premise of ensuring that the grade of P2O5 in phosphate concentrate is higher than 30.00% and the recovery rate of P2O5 is more than 40.00%，the dosage of reagent is reduced by 46.15%，and the cost of collector reagent is reduced by 34.19%. Satisfactory test results are obtained.

Key words: iron beneficiation tailings, fatty acid, apatite, iron dolomite, anhydrite, collector