Patent ID: 8790442

Claim:
A method for producing metallic iron nodules comprising the steps of: assembling a hearth furnace having a moveable hearth comprising refractory material and having at least a conversion zone and a fusion zone, providing a hearth material layer comprising carbonaceous material on the refractory material, providing a layer of reducible material comprising reducing material and iron bearing material arranged in a plurality of discrete portions over at least a portion of the hearth material layer, delivering oxygen gas into the hearth furnace in the conversion and fusion zones at a ratio of at least 0.7:1 pounds of oxygen to pounds of iron in the reducible material to heat the conversion zone to a temperature sufficient to at least partially reduce the reducible material and to heat the fusion zone to a temperature sufficient to at least partially reduce the reducible material, and heating the layer of reducible material to form from the discrete portions one or more metallic iron nodules and slag.