METHOD OF PREPARING IRON-CONTAINING COAGULANT Russian patent published in 2011 - IPC C02F1/52 C22B3/44 C01G49/02 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of preparing iron-containing coagulant from spent chloride and sulphate etching solutions of steel rolling mills, and can be used in ecology and water treatment. The method of preparing iron-containing coagulant involves oxidation of iron (II) to iron (III) with sodium hypochlorite as an oxidising agent. Concentrated solutions of the coagulant are obtained by oxidising spent etching solutions containing iron (II) sulphate and chloride. The obtained suspension is treated with mineral acid until the precipitate dissolves. The oxidation process takes place at room temperature.

EFFECT: method simplifies and improves the process of recycling spent etching solutions, and reduces formation of by-products which pollute the environment; method enables to include all types of iron-containing spent etching solutions into the recycling cycle.

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