METHOD OF PROCESSING SPENT ACID SOLUTIONS OF ELECTROPLATING PRODUCTION Russian patent published in 2019 - IPC C25D21/16 

FIELD: technological processes.

SUBSTANCE: invention relates to decontamination of galvanic production wastes containing heavy metals, wastes from mining enterprises of dolomite dust. Method comprises treatment of solution by production wastage until set values of pH for each metal in obtained mixture, addition of the next portion of waste, settling the obtained mixture for 15–20 minutes at 90–95 °C, separation of precipitation by filtration and use of filtrate as a liquid for production of concrete, wherein treatment of solution is carried out by dolomite production in form of dolomite dust, which is added in three steps to pH = 5.5–6.0 at first step, pH = 6.2–7.5 at second step and pH = 7.7–9.7 at third stage, wherein at each stage after settling, obtained mixture is cooled to 40–50 °C, obtained precipitation is simultaneously dried and milled to particle size of 15–20 mcm in drier of "boiling bed", recovered filtrates are transmitted to next stage, wherein at first step a precipitate is obtained in form of copper hydroxide, which is dried in reducing atmosphere at temperature of 120–130 °C and obtaining copper oxide, at the second step, obtaining nickel hydroxide, which is dried and nickel oxide is obtained, on the third one – iron hydroxide, which after extraction is additionally treated with 0.6–0.8 % of used solution of silumin etching, and dried at temperature of 90–100 °C or 230–240 °C, iron-oxide pigment of yellow or red colour is obtained.

EFFECT: method makes it possible to efficiently carry out practically waste-free processing of spent acid solutions of galvanic production and dolomite production wastes.

1 cl, 4 ex, 1 dwg