Method of preparing iron powder
AssigneeMidrex Corporation
InventorCharles M. Jaco, Jr.
Life of this patent
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Abstract
A method for preparing iron powder for powder metallurgy and other applications from particulate iron oxide by reducing the particle size of at least part of the particulate feed material chemically reducing the feed material to increase the percentage of metallization by contact with a gaseous reductant in a shaft furnace at high temperatures, and removing the reduced iron powder product from the furnace. Preferably the product is screened and oversized material is returned to the furnace for additional reduction. An alternative method contemplates additional steps of grinding, and further decrepitation to reduce the particle size of the larger particle fractions.
Claims14
A method for preparing iron powder from feed material selected from the group comprising particulate iron ore, lump iron ore iron oxide fines, pellets, nodules, balls, partially reduced iron and mixtures thereof, said method comprising:
- a. selecting ores which are subject to decrepitation to be included in the feed material;
- b. reducing the particle size of said feed materials;
- c. establishing continuous a gravitational flow of said feed material through a generally vertical direct reduction shaft furnace;
- d. chemically reducing said feed material by counter-current flow of a gaseous reductant through said feed material in said direct reduction furnace;
- e. controlling the reducing gas temperature between about 1550.degree. and 2050.degree. F to promote degradation of the feed material in said furnace;
- f. controlling the pressure in the reduction furnace between 3 and 15 pounds per square inch to promote degradation;
- and
- g. removing the reduced iron powder product from the furnace.
Dependencies are inferred from the claim text.