Patent ID: 8287621

Claim:
A method for producing metallic iron nodules comprising the steps of: providing a hearth comprising refractory material; providing reducible mixture above at least a portion of the refractory material, the reducible mixture comprising at least reducing material and reducible iron bearing material; forming a reducible mixture comprising: a quantity of reducible iron bearing material, a quantity of first carbonaceous reducing material of a size less than about 48 mesh of an amount between about 65 percent and about 95 percent of a stoichiometric amount necessary for complete iron reduction of the reducible iron bearing material, and a quantity of second carbonaceous reducing material with an average particle size greater than average particle size of the first carbonaceous reducing material and a size between about 3 mesh and about 48 mesh of an amount between about 20 percent and about 60 percent of a stoichiometric amount of necessary for complete iron reduction of the reducible iron bearing material; where amount of first carbonaceous reducing material and second carbonaceous reducing material provide total reducing material carbon between about 110 and 150 percent of a stoichiometric amount necessary for complete iron reduction of the reducible iron bearing material, and thermally treating the reducible mixture in the presence of other carbonaceous material separate from the reducible mixture to form metallic iron nodules.