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: A discharge assembly for removing material from a hearth in a rotary hearth furnace. The discharge assembly includes, in combination, a discharge auger and a fluid cooled hood. 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. The fluid cooled hood is disposed over the discharge auger to lower the temperature of the helical flights.

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.

Abstract: A method and apparatus are provided to control the burning of a lean hydrocarbon containing gas stream under stable conditions using a combination of control logic and hardware. Temperature within the combustor is controlled by using a plurality of staging valves that adjust the amount of oxygen and auxiliary fuel supplied to the combustor burner. Oxygen level is controlled by using actuated butterfly valves that control the flow of primary air to the combustor. The system has pressure control valves for anticipating and compensating for pressure changes and resulting air flow changes as well as temperature monitors and transmitters for anticipating and correcting temperature drops.

Abstract: A method and apparatus for controlling the operation of a plurality of burners of a cupola. The method includes the steps of separately supplying air and fuel to each burner of the cupola, measuring the flow rates of air and fuel supplied to each burner, controlling either the flow rate of air or flow rate of fuel supplied to each burner as a function of a desired heat energy output of the burners and controlling the other of the flow rate supplied to each burner as a function of the measured flow rate of air or fuel supplied to each burner and a preselected ratio of flow rate of air supplied to each burner and of flow rate of fuel supplied to each burner.

Abstract: A process for recovering iron from iron-bearing materials including steel mill waste and iron-bearing ores. The process includes the steps of combining the iron-bearing materials, having metal oxides including iron oxides therein, with carbonaceous material to form a dry mixture. The dry mixture is agglomerated under conditions sufficient to mobilize volatile matter from the carbonaceous material to function as a binder and bond the dry mixture and 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 2150.degree. F. to 2350.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.

Abstract: A continuous process for treating a noncaking coal to form stable char. The process includes the sequential steps of drying the coal to remove moisture therefrom and form a dry coal; pyrolyzing the dry coal by progressively heating substantially all of the coal to a temperature sufficient to vaporize and remove low end volatile materials from the coal to form char and sufficient to mobilize at least a portion of high end volatile materials within the char and at least partially collapse micropores within the char. The char is then cooled to a temperature sufficient to demobilize the volatile materials within the at least partially collapsed micropores of the char to pyrolytically passivate the char. The char is then conveyed to a reaction vessel wherein a process gas having about 3%-21% by volume oxygen flows through the reaction vessel to oxidatively passivate the coal by chemisorption of oxygen.

Abstract: According to this invention there is provided a process for the heat treatment of noncaking, noncoking coal with a process derived gaseous fuel having a variably controllable calorific heating value.

Abstract: According to this invention there is provided a process and apparatus for the ignition of a pilot burner in an inert atmosphere without substantially contaminating the inert atmosphere. The process includes the steps of providing a controlled amount of combustion air for a predetermined interval of time to the combustor then substantially simultaneously providing a controlled mixture of fuel and air to the pilot burner and to a flame generator. The controlled mixture of fuel and air to the flame generator is then periodically energized to produce a secondary flame. With the secondary flame the controlled mixture of fuel and air to the pilot burner and the combustion air is ignited to produce a pilot burner flame. The pilot burner flame is then used to ignited a mixture of main fuel and combustion air to produce a main burner flame.

Abstract: Method and apparatus is disclosed for thermally decomposing waste material from several batch furnaces plumbed into one afterburner. The afterburner is modified to mix and combust in a controlled manner an otherwise explosive mixture of fumes from several furnaces. The entire system is regulated only by the temperature of incinerated gases from the afterburner. The furnaces are operated in a sequenced, overlapping staged manner to produce a generally constant fume loading permitting significant cost savings in equipment and operation.