METHOD FOR EXTRACTION OF CHROME CONTAINED IN BATH FOR ETCHING METAL MATERIALS AND INSTALLATION FOR ITS IMPLEMENTATION Russian patent published in 2023 - IPC C23F1/46 C23G1/36 C22B34/32 C01G37/00 

FIELD: etching of chromium-containing metal materials.

SUBSTANCE: method and apparatus are proposed for extracting chromium contained in a pickling bath for pickling metal materials, which is located in a vat and is an aqueous solution containing at least one sulphate and chromium originating from the metal being pickled. In the method, an aqueous two-phase system is formed from at least one part of the said pickling bath and from a selected polymer containing a sterically unhindered ether functional group, wherein the aqueous two-phase system contains a polymer phase in which most of the chromium is found, and a non-polymer phase. In the method, said polymer and non-polymer phases are separated, chromium-containing precipitates are left to form in the polymer phase, solid-liquid separation is carried out on said polymer phase to separate the polymer and chromium-containing precipitates, and said chromium-containing precipitates are processed to extract the chromium contained therein.

EFFECT: regeneration of spent pickling baths containing relatively high amounts of one or more sulphur-containing compounds, such as sulphates, is achieved by removing chromium from said spent pickling baths.

19 cl, 4 dwg