Process of producing pure iron powder and product thereof

摘要

1,127,145. Treatment of iron oxides. CENTRO SPERIMENTALE METALLURGICO S.p.A. 15 June, 1966 [23 June, 1965], No. 26646/66. Heading C1A. [Also in Division C7] A process for producing iron powder from a slime of red fume powder, i.e. the iron oxide fume produced in the conversion of pig iron in oxygen blowing converters, comprises the steps: (a) drying to form a compact agglomerate containing 0À5-1À0% water, (b) crushing and screening the agglomerate, (c) heating the particles to about 1000-1200‹ C. to consolidate them and (d) reducing the iron oxide particles at about 800-900‹ C. in a fluidized bed, a fixed bed, or a rotary kiln reactor with reducing gases, such as hydrogen or carbon monoxide, or with a solid or liquid reductant such as carbon black, charcoal or oil coke. The hot iron powder may then be heated to about 1000-1200‹ C. for 10-30 minutes in a non-oxidizing atmosphere before exposure to air. Iron oxide powder containing 5-20% water or red fume powder mixed with water, exhausted sulphuric pickling bath liquor, or solutions of ferrous sulphate or of cellulose derivations may also be used as the starting material. The reducing gases used may travel counter-current to the ferrous materials and may be heated to the temperature required for the reduction by heat exchange with the hot iron powder product. The iron oxide may be heated in step (c) by the combustion of the spent reducing gases but alternatively the spent gas may be enriched and recycled.