Abstract: A rotary hearth furnace for treating metal oxide materials comprises a hearth mounted for rotary movement within an enclosure. One or more fuel burners are positioned above the hearth. The burners are operably fired to heat the furnace so that heat radiates toward the hearth. One or more oxygen nozzles are positioned between the hearth and the burners in a manner that avoids substantial contact between the oxygen and the briquettes, thereby creating a quiescent zone immediately above the briquettes, with the quiescent zone being sufficient to minimize reoxidation of the reduced briquettes, and minimize entrainment of particulate matter from the briquettes.

Abstract: A rotary hearth furnace for treating metal oxide materials comprises a hearth mounted for rotary movement within an enclosure. One or more fuel burners are positioned above the hearth. The burners are operably fired to heat the furnace so that heat radiates toward the hearth. One or more oxygen nozzles are positioned between the hearth and the burners in a manner that avoids substantial contact between the oxygen and the briquettes, thereby creating a quiescent zone immediately above the briquettes, with the quiescent zone being sufficient to minimize reoxidation of the reduced briquettes, and minimize entrainment of particulate matter from the briquettes.

Abstract: An apparatus for charging feed material through an opening into a furnace has a fixed structure and a moveable door. The moveable door together with the fixed structure defines the opening. The moveable door is mounted for movement toward and away from the fixed structure to widen and narrow the opening. The moveable door is biased toward the fixed structure. The moveable door and the fixed structure create a V-shaped downwardly pointing channel to direct the feed material being fed through the opening by gravity.

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.