METHOD OF DISPOSAL OF WASTE METAL ETCHING SOLUTION Russian patent published in 2021 - IPC C23G1/36 C23F1/46 C02F1/02 C02F103/16 

FIELD: metallurgy; machine-building industry.

SUBSTANCE: invention relates to the utilization of waste sulfuric acid etching solutions of metallurgical and machine-building industries. In the method, the waste sulfuric acid solution of metal etching is neutralized by screening the electro-steelmaking slag at the following ratio, wt.%: waste sulfuric acid solution of metal etching 74-76, screening the electro-steelmaking slag 24-26. Neutralization is carried out when the temperature rises to 80-90℃ and with pH value of 7.0-7.5 to obtain a suspension containing calcium, magnesium and iron hydroxide sulfates, which is cooled to 20℃ and transferred to a vacuum crystallizer. Crystallohydrates of calcium and magnesium sulfates are obtained, which, together with unreacted oxides of silicon, aluminum, and calcium, are separated by a centrifuge and fed to a combined fluidized layer dryer for their grinding to a particle size of 15-20 mcm and simultaneous drying at a temperature of 140-350℃ to obtain a binder. At a drying temperature of 140℃, a binder with a yellow iron-oxide pigment is obtained, and at a drying temperature of 350℃, with a red iron-oxide pigment.

EFFECT: processing of the waste sulfuric acid solution of metal etching is provided to obtain a binder suitable for the manufacture of high-strength building materials for external use.

1 cl, 1 tbl, 2 ex, 1 dwg