The invention discloses a method for synergistically improving barren
loess of a northern open pit
coal mine dumping site through
red mud magnetizing
roasting iron separation residues and
coal mine black water, the
red mud residues can be harmlessly treated and recycled through magnetizing
roasting and water
quenching cooling, the
red mud residues are utilized by 100%, the stockpiling occupied area of each
ton of red mud is reduced by 0.5 m < 3 >, and soil improvement (1% of the red mud magnetizing
roasting iron separation residues and 1% of the
coal mine black water) is achieved. The field
water holding rate of the barren
loess in the mining area can be increased from 46.37% to 62%, the saturation infiltration rate can be reduced from 70.32 mm / h to 52 mm / h, the volume weight can be reduced by 12%, the
nitrogen leaching loss can be reduced by 40%, the
organic matter can be increased from 0.8% to 2.1%, and through specific magnetizing roasting parameters (the ratio of the red mud to the lignite is 100: 35, the temperature is 1000-1200 DEG C, and the time is 90-150 min, the yield of the
loess in the mining area can be increased by 20%). The conversion from the red mud-based
hematite to the magnetic
hematite and the
dissolution of Na2O (orthogonal experiment
verification) are realized (the
optimal combination is 100: 35 / 1100 DEG C / 120min), and water
quenching cooling (the rate gt; and then carrying out 0.5-1.0 T
magnetic separation to obtain
iron ore concentrate of which the TFe is greater than or equal to 85% and residues of which the magnetic
hematite content is greater than or equal to 15%.