METHOD PROCESSING SLUDGE RESIDUE Russian patent published in 2012 - IPC C02F11/14 

FIELD: chemistry.

SUBSTANCE: invention relates to separation of suspensions and can be used when treating sewage and recycling sludge residue in coal-chemical, food and petrochemical industries. Sludge residue, which contains manganese, iron, copper, nickel and lead cations, is dried and treated with acid for 2-3 hours at 20-80°C and pH 1-5, said acid being sulphuric acid, hydrochloric acid or oxalic acid. The obtained residue which contains an insoluble lead salt is separated from the solution which is then treated with alkali at pH 7-9, and the obtained precipitate, which contains manganese, iron, copper and nickel hydroxides, is separated from the solution and dried. The aqueous solution obtained from drying is recycled and that dried residue is then treated with nitric acid at 50-170°C and pH 2-5 with addition of a precipitation agent - ammonium hydroxide. The obtained residue which contains manganese and iron oxides and the solution which contains copper and nickel cations are separated and taken for extraction.

EFFECT: method improved environmental friendliness of storing sludge residue without formation of litho-, atmo- and hydrochemical contaminants and enables to extract from the sludge residue, compounds which contain manganese, iron, copper, nickel and lead cations with subsequent separation thereof.

8 cl, 1 dwg