Patent Number: 6,251,156

Title: Method of producing molten iron in duplex furnaces

Abstract: This invention relates to a method for operation of a rotary hearth furnace in conjunction with an electric melter for production of high purity iron product having a range of silicon and manganese, with low sulfur and phosphorus content. The method includes producing high purity iron product and a range of carbon content product from iron oxide and carbon bearing compacts, including the steps of providing a furnace for direct reduction of iron oxide and carbon bearing compacts, pre-reducing iron and carbon bearing compacts in a furnace having a rotary hearth surface, producing intermediate carbon-containing metallized iron. An electric melter furnace is utilized for receiving intermediate carbon-containing metallized iron from the pre-reducing step, which is fed directly and continuously into a central interior area of the electric melter, with heating of the carbon-containing metallized iron in the electric melter under elevated temperatures of about 1300.degree. C. to about 1700.degree. C., minimizing the ingress of air or other undesirable gases such as oxygen in the melting step while maintaining elevated temperatures, and removing high purity liquid iron product from the electric melter. The method provides a high iron content product having a specified range of carbon, silicon, and manganese percentages, with low sulfur and phosphorus content. There is significant reduction of silicon oxides, and reduction of manganese oxides in the product. An extremely desirable high iron content product is produced for use by the steelmaking industry.

Inventors: Hoffman; Glenn E. (Lancaster, SC), Gray; Ronald D. (Bethel Park, PA)

Assignee: Midrex Technologies, Inc.

International Classification: C21B 13/00 (20060101); C21C 5/00 (20060101); C21B 13/10 (20060101); C21B 13/14 (20060101); C22B 1/14 (20060101); C21C 5/52 (20060101); C22B 1/24 (20060101); C21B 013/12 (); C22B 001/216 ()

Expiration Date: 06/26/2018