Method for preparing iron ore concentrates by recycling copper slag tailings

A method for preparing iron ore concentrates by recycling copper slag tailings, comprising the following steps:

• (1) purifying and absorbing SO2 flue gas with a SO2 concentration of 100-1000 mg/m3 by using copper slag tailings slurry, discharging the slurry when a concentration of SO2 at a flue gas outlet is greater than 100 mg/m3, and conducting filtering;
• (2) adding iron powder to the filtrate under stirring at room temperature to 80° C., wherein an addition amount of the iron powder is 2-5 times of a theoretical amount thereof for replacement of Cu2+ and Fe3+;
• conducting replacement reaction for 30-120 min;
• and conducting solid-liquid separation, to obtain copper-containing slag and replacement liquid;
• (3) adding a sulfiding agent to the replacement liquid for precipitation of zinc and arsenic ions, to obtain zinc-containing slag and iron-containing slurry, wherein an addition amount of the sulfiding agent is 3-8 times of a theoretical amount thereof for precipitation of the zinc and arsenic ions;
• and
• (4) placing the filter residue obtained in step (1) in a wet magnetic separation device, conducting magnetic separation in a magnetic field with intensity of 0.05-0.2 T to obtain rough iron ore concentrates and tailings, returning the tailings along an original route of a slag dump for treatment, and further conducting magnetic separation on the rough iron ore concentrates to obtain iron ore concentrates.