Patent ID: 8470068

Claim:
A method for use in production of metallic iron nuggets comprising the steps of: providing a hearth comprising refractory material, providing a hearth material layer comprising at least carbonaceous material, including at least one of anthracite, coke and char, on the refractory material, the hearth material layer being sufficiently thick to prevent slag from penetrating the hearth material layer and contacting the refractory material of the hearth, providing a layer of reducible mixture comprising at least reducing material and reducible iron bearing material over at least a portion of the hearth material layer, providing an overlayer of coarse carbonaceous material of at least about ½ inch (12.7 mm) thick and between about 0.5 lb/ft 2 (2.44 kg/m 2 )and about 1 lb/ft 2 (4.88 kg/m 2 ) comprising discrete particles having sizes greater than about 20 mesh and having an average particle size greater than an average particle size of the hearth material layer carbonaceous material over at least a portion of the layer of reducible mixture, and heating the layer of reducible mixture to form one or more metallic iron nuggets and slag.