METHOD OF PROCESSING ZINC-CONTAINING WASTE OF FERROUS METALLURGY Russian patent published in 2007 - IPC C22B19/20 C22B7/00 

FIELD: ferrous and non-ferrous metallurgy; processing blast-furnace sludge for obtaining lumped material suitable for blast-furnace melting by zinc content, as well as zinc sublimates for subsequent extraction of zinc.

SUBSTANCE: proposed method includes preparation of starting raw charge; zinc-containing blast-furnace sludge is first dried to moisture content not exceeding 3-4% and is mixed with binder containing calcium hydroxide and/or bentonite and circulating materials. Mixture is ground, moistened and lumped for obtaining pellets and briquettes. Lumped material is subjected to high-temperature treatment at heating rate of 10-30 deg/min (preferably, 20 deg/min) to temperature of 1110-1230C (preferably, 1200C) and is kept at this temperature for 20-40 minutes, after which it is discharged through hot end of furnace, cooled down and is subjected to separation by sizing; separated fines are returned for grinding the charge and/or are used for blast-furnace melting. Dust-and-gas mixture is evacuated from furnace through its cold end and is subjected to processing for separation of zinc iron-containing dust and zinc sublimates by know methods. Besides that, blast-furnace sludge is processed at addition of converter sludge of steel making process into charge. Lumped material is heated to temperature of 1110-1150C (preferably up to 1120C). Roasted lumped material is subjected to screening for separation of minus 5 mm fraction which is directed for grinding the mixture of blast-furnace sludge and binder. In case of deficiency of carbon in charge, use is made of peat as carbon reductant which is introduced under layer of pumped material during transportation into roasting furnace.

EFFECT: improved quality of products.

4 cl, 3 tbl, 3 ex