Abstract: A furnace discharge system for removing material from a hearth (18) of a rotary hearth furnace (10) and method of operation. The system includes at least two material discharge augers (28, 30) positioned above the hearth (18) of the rotary hearth furnace (10). Each discharge auger (28, 30) is operatively mounted to allow for height adjustment of the discharge auger (28, 30) in alternating sequence from a material removal position to an elevated material by-pass position.

Abstract: A rotary hearth furnace for reducing a feed material is disclosed. The rotary hearth furnace includes a rotating hearth disposed in an enclosure and mounted for rotary movement. The enclosure includes an annular inner wall, an annular outer wall and a roof. The enclosure is sealed to the hearth and divided into a plurality of zones including at least a loading zone, a process zone and a discharge zone. The furnace further includes a plurality of burners positioned in at least the outer wall of the enclosure to provide a controlled temperature within the rotary hearth furnace and a flue positioned within the reduction zone of the furnace between the preheat zone and the discharge zone to exhaust combustion gases from the burners and gases resulting from the processing of the feed material. Said flue contains space for combustion and settling of the unburned particulates.

Abstract: A process for recovering iron from iron-bearing materials including steel mill waste and iron-bearing ores. The process includes the steps of providing a mixture of iron-bearing materials having iron oxides therein and carbonaceous material. Blending with the mixture an organic binder. The mixture is then agglomerated to form green compacts. The green compacts are then loaded into a preheated rotary hearth furnace void of compacts to form a layer of compacts no more than about two compacts high. The green compacts are heated for about 5-12 minutes at a temperature of between about 2200-2500° F. to reduce the compacts and evolve undesirable oxides from the compacts. The reduced compacts are then discharged from the rotary hearth furnace whereupon they are soaked to provide additional time for reaction to achieve 99% or more reduction of the iron oxides. The metallized iron compacts may then be cooled or transported hot to a steel making operation.

Abstract: A screw having a field replaceable flight. The screw includes a barrel and a helical flighting that is removably attached to the barrel by a plurality of brackets. The helical flighting includes a plurality of segments, each segment includes first and second opposing faces having an opening extending there though and side edges. The segments are positioned side by side to generally cooperatively form the flighting of the screw. At least one face of each segment includes raised bosses. The raised bosses project perpendicularly outwardly from the face of the segment to form a pocket within which the bracket is received. The segments are removably attached to the barrel by inserting a segment forming part of the flighting within the pocket and then removably fastening the segment within the pocket.

Abstract: A discharge assembly for removing material from a hearth in a rotary hearth furnace including a discharge auger and a coolant spray. The discharge auger is positioned above the hearth of the rotary hearth furnace and includes a central shaft having at least one helical flight affixed to the exterior of the central shaft and the hood is disposed above the discharge auger. The coolant spray cools the discharge auger.

Abstract: An apparatus for charging a feed material onto a rotating hearth of a rotary hearth furnace, the rotary hearth furnace including refractory lined inner and outer walls and having a refractory roof supported thereon, the apparatus comprising a table mounted above the rotating hearth and capable of receiving feed material from outside of the rotary hearth furnace, the table extends transversely across the rotating hearth and having a first end including a distribution member, a second end including a plurality of discharge slots, and an intermediate leveling plow; wherein feed material free falls over said distribution member and is distributed across the width of the table and then adjusted to a uniform depth such that as the rotating hearth passes under the stationary table a curtain of feed material is loaded onto the hearth.

Abstract: A process for treating iron-bearing material with a carbonaceous material to form a mixture, wherein the amount of carbonaceous material added exceeds the stoichiometric amount required to reduce the metal oxide to elemental metal. In one embodiment, the process also includes blending an organic binder with the mixture. The mixture is agglomerated using compaction to bond the mixture and form green compacts. The green compacts are loaded into a heated furnace and heated for about 5-12 minutes at a temperature of between about 2100.degree.-2500.degree. F. and at a CO/CO.sub.2 ratio of about 1.5-2.5 proximate the discharge area to reduce the iron oxide containing compacts to compacts containing elemental iron and an excess amount of carbonaceous material wherein the excess amount of carbonaceous material counteracts re-oxidation of the elemental iron. The reduced compacts are then discharged from the furnace.

Abstract: A process for recovering iron from iron-bearing materials including steel mill waste and iron-bearing ores. The process includes the steps of providing a mixture of iron-bearing materials having iron oxides therein and carbonaceous material. The mixture is agglomerated to form green compacts. The green compacts are then loaded into a preheated rotary hearth furnace void of compacts to form a layer of compacts no more than about two compacts high. The green compacts are heated for about 5 to 12 minutes at a temperature of between about 2200.degree. F. to 2500.degree. F. to reduce the compacts and evolve undesirable oxides from the compacts. The reduced compacts are then discharged from the rotary hearth furnace whereupon they are soaked to provide additional time for reaction to achieve 99% or more reduction of the iron oxides. The metallized iron compacts may then be cooled or transported hot to a steel making operation.

Abstract: A process for treating iron-bearing material with a carbonaceous material to form a dry mixture, wherein the amount of carbonaceous material added exceeds the stoichiometric amount required to reduce the metal oxide to elemental metal. In one embodiment, the process also includes blending an organic binder with the dry mixture. The dry mixture is agglomerated to bond the dry mixture and form green compacts. The green compacts are loaded into a heated furnace and heated for about 5-12 minutes at a temperature of between about 2100.degree.-2500.degree. F. to reduce the iron oxide containing compacts to compacts containing elemental iron and an excess amount of carbonaceous material wherein the excess amount of carbonaceous material counteracts re-oxidation of the elemental iron. The reduced compacts are then discharged from the furnace.