Recycling harmless treatment method of stainless steel pickling waste water

The invention discloses a recycling harmless treatment method of stainless steel pickling waste water, belonging to the toxic and harmful industrial waste water treatment field. The method comprises the following steps of: 1) recycling inorganic acids by an acid separation method: pumping stainless steel pickling waste water in which suspended matters are removed through filtering into a resin column so that the inorganic acids are absorbed on the resin; 2) removing impurities by a goethite method: pumping heavy metal ion solution into a reaction kettle, adjusting pH to a range from 3.5 to 5.0, and continuing reacting for 30-90 min, thereby removing iron, chromium and fluorine in the heavy metal ion solution in the form of dregs; 3) recycling nickel by a neutralized sedimentation method: feeding an alkaline liquor to nickel solution to adjust pH to a range from 9.5 to 12.5, and filtering and washing the filter residues, thereby obtaining nickelous hydroxide; and 4) performing harmlesstreatment on the dregs: a