METHOD FOR PROCESSING WASTE OF IRON CHLORIDE SOLUTIONS Russian patent published in 2021 - IPC C23G1/36 C25F7/02 C01G49/10 C01B7/07 

FIELD: metallurgy.

SUBSTANCE: invention relates to ferrous metallurgy and chemical industry, in particular, to the processes of etching carbon and special steels with recycled hydrochloric acid, and can be used for regeneration of spent etching solutions with associated production of a pure iron oxide powder. The processing of spent hydrochloric acid etching solutions containing iron (II) chlorides and/or iron (III) chlorides includes the stage of hydrolysis of the solution and the stage of recovering solid iron oxide with condensation of hydrogen chloride. The hydrolysis of the solution is executed at a temperature of 200 to 250°C, followed by sustaining the solution after the stage of hydrolysis for no more than 180 minutes. Prior to the stage of recovering solid iron oxide, the solution is cooled by self-evaporation at a rate of 10 to 15°C to a temperature of 20 to 90°C, followed by isolating solid iron oxide from the liquid.

EFFECT: invention makes it possible to conserve heat energy as required to implement the process of regeneration of an etching solution, to reduce the amount of technological operations, to return the regenerated acid to the process, and to produce finely dispersed iron oxide.

8 cl, 2 tbl, 7 ex