The invention discloses a method for producing ferroferric
oxide magnetic powder by recycling
industrial waste acid and
red mud. The method comprises the steps of: mixing
hydrochloric acid waste liquid with the
red mud according to a ratio of (3-5):1; lifting a
mixed solution of an initial reaction to a
mixed solution filter through a pump, wherein a filtrate flows into a filtrate
storage tank, filter residues are subjected to pressure
filtration reduction through a plate-and-frame
filter press, then the treated filter residues are transported outwards for disposal, and a plate-and-frame pressure
filtration solution is returned back into a waste acid solution
storage tank for recycling; lifting a mixed suspension after
filtration into a reaction kettle by a pump, heating the reaction kettle to 80-90 DEG C, adding an oxidant and an alkaline solution into the
mixed solution at the same time, wherein a stirring
system is arranged in the reaction kettle to ensure uniformity and high efficiency of the reaction, and allowing the mixed solution to react in the reaction kettle to generate hydrous ferroferric
oxide magnetic powder; performing
magnetic separation on wet ferroferric
oxide, and performing
water washing to obtain a ferroferric oxide
magnetic powder crude product, and
drying the crude product and purifying the dried crude product to form high-purity ferroferric oxide magnetic
powder. The method disclosed by the invention reduces the treatment cost for hazardous wastes and waste acid liquid, and the obtained product is stable in quality and performance and is safe. An environmental and economic benefit win-win effect is achieved.