METHOD OF DEEP RECYCLING IRON-CONTAINING WASTES Russian patent published in 2017 - IPC C22B7/00 C22B3/18 B82B3/00 

FIELD: chemistry.

SUBSTANCE: method comprises precipitating from the said solutions of solid ferrous sulfate of ferrous divalent Fe₂SO₄⋅7H₂O. Then it is sent to biooxidation solution, consisting of cultivated on a nutrient medium 9K microorganisms Ac. ferrooxidans and Ac. Thiooxidans, in a continuous vapour regime with a flow at atmospheric pressure for 12-50 hours at an average oxidation rate of 1-1.5 g/l per hour with transfer of ferrous iron to trivalent. Further, alkali is added to increase the pH of the solution and to obtain a precipitate of solid ferrous sulfate and to perform its ultrasonic work-up to obtain a product for the production of iron oxide pigments.

EFFECT: increasing the depth of processing of iron-containing waste, reducing waste disposal costs and obtaining highly liquid transparent nanoscale pigments.

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