SYSTEM AND METHOD FOR COOLING AND REMOVING IRON FROM A HEARTH
A system and method for cooling and removing metallic iron and other aggregate from a moving hearth is provided. Cooling may be provided by a secondary cooling system and a spray cooling system in a cooling zone. The secondary cooling system may include an arrangement of coolant tubes for absorbing heat. A flow of nitrogen may be provided through the cooling zone. The spray cooling system may provide evaporative cooling. Aggregate removal may be provided by a magnetic removal system, a plow system, and a sweeper system. The magnetic removal system uses a magnetic device and a moving belt to remove iron materials. The plow system uses a plow to separate and remove aggregate from the moving hearth. The sweeper system may use a vacuum device to pull materials from the moving hearth.
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This patent application is the national stage application of international application PCT/2008/050855, filed Jan. 11, 2008, which claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 60/884,829 filed on Jan. 12, 2007, the disclosure of which is hereby incorporated by reference.
GOVERNMENT INTERESTSThe present invention was made with support by the Economic Development Administration, Grant No. 06-69-04501, and the Department of Energy, Sponsor Award DE-FG36-05G015185. The United States government may have certain rights in the invention.
BACKGROUND AND SUMMARY OF DISCLOSUREDirect reduction of iron ore and other iron oxides with a source of carbon in a controlled hearth furnace results in an aggregation of reduced metallic iron nodules, slag and carbon-bearing material at high temperature, which needs to be efficiently cooled, separated and selectively removed from a moving hearth. The iron oxide source may be mixed with finely divided carbon-bearing materials such as coke or coal, and on a layer of carbon-bearing material to protect the moving hearth.
One method of processing iron ore uses a moving hearth furnace operated at temperatures reaching up to 2,500° F. (1,370° C.) or higher. The iron oxide and carbon-bearing reducing materials may travel through the furnace on a moving hearth at temperatures up to 2,500° F. (1,370° C.) or higher, and result in reduced metallic iron mixed with slag, carbon-bearing material and other by-products on the moving hearth before cooling. A continuous process may be maintained by using a linear hearth furnace or rotary hearth furnace, wherein the raw materials travel through various controlled processing environments inside the moving hearth furnace.
There is need for a system for continuously handling such high temperature iron and carbon-bearing materials. Removal systems in the prior art have provided apparatus and systems for handling some of these materials in an ambient environment (e.g. less than about 120° F. (about 50° C.)). These systems and apparatus cannot operate successfully for long periods in environments up to 500° F. (about 260° C.), 800° F. (about 425° C.), or higher, or involve handling all these materials in aggregate as presented in a moving hearth for direct reduction of metallic iron in a commercial plant.
The present disclosure provides a system and method for efficient cooling of the aggregation, removal of the metallic iron nodules at relatively high temperature, separation of slag from the removed metallic iron nodules, and selective removal and classification of slag and carbon-bearing material, while leaving a selected and controlled amount of the carbon-bearing material on the moving hearth ready for reuse in the moving hearth furnace.
A method of removing metallic iron and associated materials from a moving hearth may comprise the steps of:
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- a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. cooling the aggregate on the moving hearth in a cooling zone by secondary cooling, such as coolant tubes, generally to a temperature in the adjacent atmosphere at or below about 1200° F.;
- c. optionally spraying water over the aggregate on the moving hearth to cool the aggregate on the moving hearth by evaporation without substantial water run off generally to a temperature in the adjacent atmosphere at or below about 800° F.;
- d. causing the moving hearth supporting aggregate to move beneath a moving belt positioned between the moving hearth and a magnetic device; and
- e. removing magnetic material from the moving hearth by using the magnetic device to remove magnetic material from the aggregate, and moving the removed magnetic material for separate processing.
Secondary cooling of the aggregate in the method may include providing a plurality of coolant tubes, positioned adjacent the aggregate, through which coolant such as water is circulated.
The method for removing metallic iron and carbon-bearing and slag materials from a moving hearth may include moving the removed magnetic material transverse to, or along, the direction of travel of the hearth. The material may be removed at a velocity in a range of about 20 to 100 feet per minute (about 6 to 30 meters per minute). Alternately, the material may be removed at a higher speed, such as a velocity of about 100 to 400 feet per minute (about 30 to 120 meters per minute), and may be impacted against a surface to assist in separating metallic iron material from slag.
The method may include causing the moving hearth to move beneath a belt, the belt supported by a drum capable of moving removed magnetic material traverse or along the direction of the hearth. The drum may include a magnetic device adjacent the belt. The magnetic device, which may be in the drum or adjacent the belt, may be cooled by coolant if desired.
The method may also include the steps of moving the hearth beneath a plow capable of selectively removing a regulatable amount of aggregate, and moving the hearth beneath a sweeper capable of selectively removing a regulatable amount of aggregate. The step of moving the hearth beneath a plow may include removing aggregate over a plow edge and adjacent inclined surface, and brushing the removed aggregate to a conveying device. The step of moving the hearth beneath a sweeper may include removing aggregate using a vacuum device.
The method may further include separating the removed aggregate according to size, and returning classified particles smaller than a selected size to the moving hearth.
The system for removing metallic iron and associated materials from a moving hearth may comprise:
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- a. a moving hearth capable of supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. a cooling zone capable of cooling the aggregate on the moving hearth by secondary cooling, such as coolant tubes, generally to a temperature in the adjacent atmosphere at or below about 1200° F.;
- c. optionally, a spray of water capable of cooling the aggregate on the moving hearth to a temperature in the adjacent atmosphere generally at or below about 800° F. by evaporation without substantial water run off; and
- d. a moving belt positioned between a magnetic device and the moving hearth, the magnetic device being capable of removing magnetic material from the aggregate, and the moving belt being capable of moving the removed material traverse or along the direction of travel of the moving hearth for separate processing.
The secondary cooling may include a plurality of coolant tubes, positioned adjacent the aggregate, through which coolant such as water may be circulated.
The moving belt may be positioned traverse or along the direction of movement of the hearth. The belt may move at a velocity in a range of about 20 to 100 feet per minute (about 6 to 30 meters per minute). Alternately, the belt may move at a higher speed, such as a velocity of about 100 to 400 feet per minute (about 30 to 120 meters per minute). The moving belt may be capable of impacting the removed material against a surface to assist in separation of metallic iron material from slag.
The system may include a drum positioned traverse or along the moving hearth and supporting a belt capable of moving removed material traverse or along the direction of the hearth. The drum may include a magnetic device, and the drum and/or magnetic device may be cooled by coolant.
The system may include a plow and a sweeper. The plow may include a plow edge and adjacent inclined surface, and a brush adjacent the surface. The sweeper may include a vacuum.
Referring now to
The furnace 10 may be used for processing iron oxide and carbon-bearing materials at selected temperatures for providing metallic iron materials. Aggregate material for processing, including metallic iron materials, carbon-bearing materials, and other associated material may move through the furnace 10 on the moving hearth 30. In some embodiments, a track 32 may cause the hearth 30 to move through the furnace 10. At a discharge portion of the furnace 10, the hearth 30 may move past the baffle 22 through an opening 34 to enter the cooling zone 24. The fusion zone 20 may have a controlled atmosphere having a temperature up to about 2,500° F. (1,370° C.) or more. Further, the aggregate on the moving hearth 30 moving from the fusion zone 20 into the cooling zone 24 may have a temperature of up to about 2,500° F. (1,370° C.) or more.
The aggregate, including selected ferrous, carbon-bearing, and other materials for processing, may be loaded onto the moving hearth 30 in layers. After processing, the products and by-products of the process may remain on the hearth 30 in layers. For example, the moving hearth 30 may support aggregate in a hearth layer 62 and a layer of reduced metallic iron material 66, as illustrated by
The hearth layer 62 may be used to cover and protect the surface of the moving hearth 30. The hearth layer 62 may be a carbon-bearing material such as coke, coal, or char. The hearth layer 62 may have a thickness capable of protecting the moving hearth 30 from slag and other by-products of the hearth furnace process. The protective hearth layer 62 may be re-used in subsequent hearth furnace processes through the furnace. As such, the iron removal system may leave a portion of the hearth layer 62 on the hearth. Alternately, the hearth layer 62 may be removed if desired.
The moving hearth 30 may comprise a hearth surface 50 and raised curbs 56 along the left-hand and right-hand sides of the hearth surface 50. The moving hearth 30 may comprise a plurality of sections or segments, such as but not limited to hearth cars, positioned end to end along the track 32. The plurality of sections of the moving hearth 30 may be arranged in a contiguous line on the track 32, such that the hearth surface 50 can extend through the furnace 10 as an approximately continuous surface. After the moving hearth 30 exits the furnace 10, the track 32 may continue in a return loop back to the entrance of the furnace.
The hearth sections may be moved by suitable drive apparatus, such as chains, hydraulics, belts, or other drive mechanisms. The drive apparatus may cause one hearth section or segment to push against the hearth section in front of it, which correspondingly pushes the next section forward, continuing as such, thereby causing the sections of the moving hearth 30 to maintain contact and to move in a line through the furnace along the track 32. The moving hearth 30 may comprise a plurality of sections connected together by linkages so that the sections do not appreciably separate as the moving hearth travels through the furnace.
In the embodiment of
The cooling zone 24 may cool the aggregate on the moving hearth by secondary cooling, such as coolant tubes, generally to a temperature in the adjacent atmosphere at or below about 1200° F. The cooling zone 24 may comprise the secondary cooling system 36. The temperature of the adjacent atmosphere at the exit of the secondary cooling system 36 may be in a range of approximately 800 to 1200° F. (approximately 425 to 650° C.) or lower.
In the embodiment of
The coolant tubes 70 of the secondary cooling system 36 may be enclosed by the furnace housing 26 as shown in
The coolant tubes 70 may pass over the moving hearth 30 in a serpentine or S-shaped configuration as illustrated in
In the serpentine configuration of
The coolant tubes 70 with circulating coolant inside comprise the secondary cooling system 36, which absorbs heat from the aggregate, and may circulate through a conditioning process to remove heat from the coolant. The coolant may be routed to a heat exchanger to extract heat for other uses or to a cooling tower to dissipate the absorbed heat from the aggregate. In an alternate embodiment, the coolant tubes 70 may be divided into two or more zones. A first zone of coolant tubes 70 may be routed to a heat exchanger to extract heat for use, and a second zone may be routed to a cooling tower for dissipation of heat.
In the embodiment of
Additional cooling may be provided by providing a flow of gas over the moving hearth 30 in the cooling zone 24. The flow of gas may be nitrogen or other inert gas. Nitrogen evaporated from liquid nitrogen may be introduced into the furnace housing 26. The gas may flow over the moving hearth and then be exhausted, processed through a heat exchanger or circulated to another part of the furnace for use. If desired, the gas may be cooled and recirculated over the moving hearth 30.
The nitrogen or other gas may flow in the direction counter to the direction of the moving hearth 30. Alternately, the gas may flow in a concurrent direction or cross flow direction, transverse to the direction of the hearth. The volume and direction of gas flow may be determined to create a turbulent flow of gas over the moving hearth. Nitrogen may flow opposite the direction of travel of the moving hearth in a volume of approximately 500 cubic feet per minute (approximately 14.2 cubic meters per minute).
The flow of gas through the cooling zone 24 may be such that the pressure in the cooling zone 24 is slightly higher than the pressure in the fusion zone 20 of the furnace. Maintaining a pressure in the cooling zone 24 slightly higher than the pressure in the fusion zone 20 may reduce leakage of the controlled atmosphere of the fusion zone 20 into the furnace housing 26. The pressure in the cooling zone 24 may be selected to reduce the amount of gas from the cooling zone 24 entering the fusion zone 20.
However, before magnetic separation, the aggregate may be partially cooled, if desired, by spray cooling system 38. The spray cooling system 38 may have a plurality of nozzles 80 for spraying liquid over the aggregate on the moving hearth 30 so as to evaporate the liquid, causing an evaporative cooling effect. The spray cooling system 38 may be positioned outside of the furnace housing 26, and may comprise a plurality of nozzles 80 capable of spraying water. It is contemplated that various spray patterns, droplet sizes, and volume flow rates may be utilized to create a suitable evaporative cooling effect. The spray cooling system 38 may dispense a spray of water over the aggregate on the moving hearth so as to substantially evaporate the water without substantial water run-off, thereby preventing the aggregate materials on the moving hearth from remaining wet. Thus, the aggregate materials may be recycled into the hearth furnace without an additional drying process. Also, an environment condition presenting the need for discharge of water is not presented.
In the embodiment of
Following the cooling zone 24, a system for removing iron may include a magnetic removal system 88 for removing metallic iron material from the moving hearth 30, along with magnetic slag. Aggregate comprising processing by-products and reactants including slag and carbon-bearing material may then be removed from the moving hearth 30 by a plow system 42. Finally, additional such material may be removed from the moving hearth 30 by a sweeper system 44. It is contemplated that a combination of one or more of these removal systems may be utilized.
The metallic iron material 66 may contain metallic iron nodules 60 and other metallic iron material. The iron removal system may remove the iron nodules 60 and other iron containing materials while leaving other aggregate, such as the hearth layer 62 on the moving hearth 30.
The metallic iron material 66 may be removed from the moving hearth 30 by the magnetic removal system 88. The magnetic removal system 88 may be capable of operating in a high temperature environment. It is contemplated that the magnetic removal system 88 may operate to continually remove metallic iron material at temperatures in the adjacent atmosphere of up to about 800° F. (approximately 425° C.), as the hearth moves beneath the removal system. In a continuous operating environment, portions of the magnetic removal system 88 may increase in temperature to approximately the same temperature as the metallic iron material 66, due to heat transfer to the removal system.
As shown in
The magnetic device 94 may be an electromagnet, a permanent magnet, or a combination of electromagnets and permanent magnets. The magnetic device 94 may be cooled by a coolant, as such water, for maintaining a selected operating temperature. Cooling for the magnetic device may be achieved by a cooling jacket, with inlets and outlets surrounding the magnetic device, bores through the magnet, or other cooling techniques. The magnetic device 94 may be connected to a cooling system capable of circulating coolant to cool the magnetic device.
The hearth 30 moves beneath the belt 90 and the magnetic device 94, causing the belt 90 to remove the metallic iron material along the direction of the moving belt 90. As the hearth advances beneath the magnetic device 94, the magnetic device attracts the iron and other magnetic metallic materials contained in the moving hearth 30. The magnetic device 94 attracts the magnetic materials and temporarily holds the magnetic materials against the intervening belt 90. The magnetic device 94 may attract other magnetic materials besides metallic iron, such as magnetic slag. There may also be slag and the like physically attached to the magnetic material attracted by the magnetic device 94.
The belt 90 may move at a velocity of about 30 feet per minute (about 9 meters per minute). In some embodiments, the belt may have a velocity within a range of approximately 20 to 100 feet per minute (about 6 to 30 meters per minute). The belt 90 may be driven at a velocity such that the attracted materials including iron and other magnetic materials that are held against the belt 90 become removed by the lower span of the continuous loop of the belt 90 in the direction of the travel of the belt indicated by the arrow marked “A” in
The belt 90 may include protrusions 96 extending from an outer surface of the belt to aid in moving the attracted metallic iron materials away from the magnetic device 94. The protrusions may be of various shapes, sizes, and orientations to move the metallic iron materials away from the magnetic device 94. The belt 90 may be made from fiberglass, austenitic stainless steel, or other appropriately nonmagnetic material capable of withstanding the temperatures encountered by the magnetic removal system 88. Alternatively or additionally, the belt 90 may have a rough surface to aid in removing the metallic iron materials.
The magnetic materials removed by the belt may be received by a collection system 100. The collection system 100 may include a collector 104 and magnetic material conveyor 106. The conveyor 106 may be a screw conveyor.
As shown in
Optionally, the removed materials may be impacted against a surface to separate metallic iron material from adhering slag and other associated material. As shown in
In an alternate embodiment illustrated in
In the embodiment of
The cooling jacket 95, positioned between the magnetic device 94 and the belt 90, is capable of cooling the magnetic devices 94 such that the magnetic devices maintain a desired temperature. The cooling jacket 95 may comprise one or more passageways 97 capable of receiving a flow of coolant. In the embodiment shown in
In the embodiment of
The magnetic removal system 188 further comprises the collector 104, and the iron material conveyor 106. In this embodiment, the conveyor 106 is a screw conveyor. The collector 104 and conveyor 106 are positioned to cooperate with the belt 90 to receive the removed material. In the embodiment of
As shown in
Multiple magnetic removal systems 88, 188 may be used to remove the metallic iron materials from the moving hearth 30. Two or more belts 90 and magnetic devices 94 may be positioned over the moving hearth 30 in a staggered arrangement. In a three-device embodiment, the first magnetic removal device may be positioned over the left edge of the moving hearth 30, the second magnetic removal device positioned over the center of the moving hearth 30, and the third magnetic removal device positioned over the right edge of the moving hearth 30. The multiple magnetic removal systems 88, 188 may be positioned in a staggered arrangement such that the second device is downstream of the first, and the third is downstream of the second to accommodate the physical structure of the devices. A first belt may remove material toward the left side of the moving hearth, and a second belt may remove material toward the right side of the moving hearth. In any event, a plurality of magnetic removal systems 88 are arranged in various staggered arrangements and orientations to accomplish removal of metallic iron materials from the width of the moving hearth 30.
The conveyor 106 may transfer removed materials to a second magnetic separator (not shown), to further separate slag from iron. The second magnetic separator may be used to further remove slag and other low- or non-magnetic aggregate from the removed material stream. Low- or non-magnetic aggregate separated by the second magnetic separator may be classified by size, where pieces smaller than −6 Tyler mesh returned to the moving hearth 30. The removed magnetic materials may be conveyed to a crusher before entering the second magnetic separator. The second magnetic separator may be a magnetic drum separator known in the art.
The iron material conveyor 106 may convey the removed iron materials to one or more totes or other material handling units. In some embodiments, the iron materials may remain in totes until the iron cools. It is contemplated that the iron materials may be conveyed to a cooling system for additional cooling. The spray cooling system 38 may dispense a spray of water over the removed magnetic material so as to evaporate and cool the removed magnetic material without substantial water run off. Optionally, additional cooling may be provided by the conveyor 106, such as by using a screw conveyor having a cooled screw, such as, but not limited to, a Therma-Flite® screw.
The plow system 42 may remove at least a portion of the aggregate including carbon-bearing reductants and other materials. The aggregate removed may include metallic iron materials, slag, other processing by-products and reactants. However, generally the plow system 42 is positioned after the magnetic removal system 88 has removed the magnetic material. The removed materials may be separated and recycled in subsequent hearth furnace processes. The plow system 42, shown in
As shown in
The plow edge is approximately stationary, as shown in
When the moving hearth 30 advances beneath the plow 112, the removed material may accumulate on the inclined surface 116. The brush 118 may be used to assist the movement of removed material along the inclined surface 116 and onto the conveyor 120, where the conveyor 120 moves the material away from the plow system 42. In the embodiment of
As shown in
In this embodiment, the roll classifier 122 is capable of being adjusted within a range of aperture sizes. The roll classifier 122 may be adjusted to an aperture size of about 6 Tyler mesh (3.327 millimeters), so that smaller particles fall through the apertures 126 between the rolls 124. The roll classifier 122 may be positioned so that material that falls between the rolls 124 falls back onto the moving hearth 30. Alternately, material that falls between the rolls may be collected and removed from the plow. Particles larger than the selected aperture size move over the rolls and into the conveyor 120.
Alternately, the classifier 122 may comprise a screen classifier in place of the roll classifier 122 (not shown). The screen classifier may comprise one or more screens having apertures of a selected size for allowing particles smaller than the selected aperture size to fall through. The screen classifier may be positioned so that material that falls through the screen falls onto the moving hearth 30. The selected aperture size may be about 6 Tyler mesh (3.327 millimeters).
In the embodiments of
Two or more plows 112 may be positioned over the hearth in a staggered arrangement. In a three-plow embodiment, the first plow may be positioned over the left edge of the moving hearth 30, the second plow positioned over the center of the hearth, and the third plow positioned over the right edge of the hearth. The multiple plows 112 may be positioned in a staggered arrangement such that the second plow is downstream of the first, and the third is downstream of the second to accommodate the physical structure of the devices. The plows 112 may feed into the aggregate conveyor 120. The plurality of plows 112 may be arranged in various staggered arrangements and orientations to accomplish removal of material from the width of the moving hearth 30. In alternate embodiments, the plows feed into two or more conveyors 120.
The aggregate conveyor 120 may convey the removed aggregate through a secondary cooling system to further reduce the temperature of the removed aggregate. The spray cooling system 38 may dispense a spray of water over the removed aggregate so as to evaporate and cool the removed aggregate without substantial water run off. Optionally, additional cooling may be provided by the conveyor 120, such as by using a screw conveyor having a cooled screw, such as, but not limited to, a Therma-Flite® screw. The spray cooling system 38 may also dispense a spray of water over the aggregate on the moving hearth after the moving hearth moves past the plow 112, so as to evaporate and cool the aggregate on the moving hearth without substantial water run off.
As shown in
The sweeper 128 may comprise a vacuum device 130 capable of being regulated to selectively remove aggregate material. In the embodiment of
The moving hearth 30 may form an approximately continuous surface, as illustrated in
To remove material from the front and rear portions of the moving hearth sections, the vacuum device 130 may activate when the front and rear portions of the moving hearth sections pass the vacuum device 130. The controller may cooperate with the moving hearth to identify when the vacuum device 130 is operatively positioned over the front and rear edges 52, 54 before selectively activating the vacuum device 130. The moving hearth sections may comprise physical features, such as but not limited to protrusions or cams that activate the controller. The controller and moving hearth may comprise controlling devices such as, but not limited to, limit switches, electric eyes, proximity switches or other suitable devices to selectively activate the sweeper 128. If desired, the sweeper 128 may remain activated continuously for removing a large portion of the material from the moving hearth 30.
The vacuum device 130 may discharge the removed material into a collector system 132. The sweeper system 44 may further comprise a sweeper system conveyor 134, where the conveyor 134 moves the material away from the collector system 132.
Multiple vacuum devices 130 may be used to remove the materials from the moving hearth 30. Two or more vacuum devices 130 are positioned over the moving hearth 30 in a staggered arrangement. In the two-vacuum embodiment shown in
The sweeper 128 may connected to a heat exchanger or cooler for cooling the air in the sweeper system 44. It is contemplated that the air may be at an elevated temperature after it passes over the moving hearth. A heat exchanger may be used to reduce the air temperature to approximately 150° F. (approximately 66° C.) or below.
The sweeper system conveyor 134 may convey the removed material through a cooling system to further reduce the temperature of the removed material. The spray cooling system 38 may dispense a spray of water over the removed aggregate so as to evaporate and cool the removed aggregate without substantial water run off. Optionally, additional cooling may be provided by the conveyor 134, such as by using a screw conveyor having a cooled screw, such as, but not limited to, a Therma-Flite® screw. It is contemplated that the sweeper system conveyor 134 and the aggregate conveyor 120 from the plow system 42 may convey material through the same cooling system. It is further contemplated that the sweeper system conveyor 134 and the aggregate conveyor 120 may be combined into one conveyor or material handling system, or alternately feed into the same material handling systems.
While the invention has been described with detailed reference to one or more embodiments, the disclosure is to be considered as illustrative and not restrictive. Modifications and alterations will occur to those skilled in the art upon a reading and understanding of this specification. It is intended to include all such modifications and alterations in so far as they come within the scope of the claims, or the equivalence thereof.
Claims
1. A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
- a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. cooling the aggregate on the moving hearth in a cooling zone by secondary cooling;
- c. spraying water over the aggregate on the moving hearth so as to evaporate and cool the aggregate on the moving hearth without substantial water run off to a temperature in the adjacent atmosphere at or below about 800° F.;
- d. causing the moving hearth supporting aggregate to move beneath a moving belt positioned between the moving hearth and a magnetic device; and
- e. removing magnetic material from the moving hearth by using the magnetic device to remove magnetic material from the aggregate.
2. The method according to claim 1, where the step of cooling the aggregate by secondary cooling comprises the step of:
- providing coolant tubes in a serpentine configuration adjacent the moving hearth, the coolant tubes being capable of circulating coolant therethrough to remove heat from the aggregate on the moving hearth.
3. The method according to claim 1, where the step of cooling the aggregate by secondary cooling comprises the step of:
- providing a plurality of coolant tubes capable of cooling the aggregate on the moving hearth to a temperature of the adjacent atmosphere at or below about 1200° F.
4. The method according to claim 1, where the step of removing magnetic material from the moving hearth comprises the step of:
- moving such removed magnetic material traverse or along the direction of travel of the moving hearth.
5. The method according to claim 4, the step of moving such removed magnetic material traverse or along the direction of travel of the moving hearth being performed at a velocity in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute).
6. The method according to claim 5, further comprising the step of:
- causing the removed magnetic removed material to be impacted against a surface to separate metallic iron material from slag and other associated material.
7. A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
- a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. cooling the aggregate on the moving hearth in a cooling zone by secondary cooling;
- c. causing the moving hearth supporting aggregate to move beneath a moving belt positioned between the moving hearth and a magnetic device;
- d. removing magnetic material from the moving hearth by using the magnetic device to remove magnetic material from the aggregate; and
- e. then moving the moving hearth with aggregate thereon beneath a plow capable of selectively removing from the hearth a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired
8. The method according to claim 7, further comprising the step of:
- spraying water over the aggregate on the moving hearth to cool the aggregate by evaporation without substantial water run off to a temperature of the adjacent atmosphere at or below about 800° F.;
9. The method according to claim 7, where the step of cooling the aggregate by secondary cooling comprises the step of:
- providing coolant tubes in a serpentine configuration adjacent the moving hearth, the coolant tubes being capable of circulating coolant therethrough and removing heat from the aggregate on the moving hearth.
10. The method according to claim 7, where the step of cooling the aggregate by secondary cooling comprises the step of:
- providing a plurality of coolant tubes capable of circulating coolant to cast the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 1200° F.
11. The method according to claim 7, where the step of removing magnetic material from the moving hearth comprises the step of:
- moving such removed magnetic material traverse or along the direction of travel of the moving hearth.
12. The method according to claim 11, where the step of moving such removed magnetic material traverse or along the direction of travel of the moving hearth is performed at a velocity in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute).
13. The method according to claim 11, further comprising the step of:
- causing the removed magnetic removed material to be impacted against a surface to separate metallic iron material from slag and other associated material.
14. The method according to claim 7, where the step of moving the moving hearth beneath a plow comprises the steps of:
- removing aggregate from the moving hearth over a plow edge and adjacent inclined surface as the hearth moves beneath the plow;
- positioning a brush adjacent to the inclined surface capable of moving aggregate along the surface of the plow; and
- brushing the removed aggregate to a conveying device to remove the removed aggregate.
15. The method according to claim 14, further comprising the steps of:
- positioning at an edge of the inclined surface a classifier for segregating the removed aggregate according to size; and
- returning classified particles smaller than a selected size to the moving hearth.
16. A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
- a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. cooling the aggregate on the moving hearth in a cooling zone by secondary cooling;
- c. spraying water over the aggregate on the moving hearth so as to evaporate and cool the aggregate on the moving hearth by evaporation without substantial water run off to a temperature at or below about 800° F.;
- d. causing the moving hearth supporting aggregate to move beneath a moving belt positioned between the moving hearth and a magnetic device;
- e. removing magnetic material from the moving hearth by using the magnetic device to remove magnetic material from the aggregate;
- f. then moving the moving hearth with aggregate thereon beneath a plow capable of selectively removing from the hearth a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired; and
- g. moving the hearth beneath a sweeper capable of selective removal of a regulated amount of aggregate from the moving hearth, and causing the sweeper to remove at least selected aggregate from the hearth.
17. The method according to claim 16, where the step of cooling the aggregate by secondary cooling comprises the step of:
- providing coolant tubes in a serpentine configuration adjacent the aggregate on the moving hearth, the coolant tubes being capable of circulating coolant therethrough to remove heat from the aggregate on the moving hearth.
18. The method according to claim 16, where the step of cooling the aggregate by secondary cooling comprises the step of:
- providing a plurality of coolant tubes capable of cooling the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 1200° F.
19. The method according to claim 16, where the step of removing magnetic material from the moving hearth comprises the step of:
- moving such removed magnetic material traverse or along the direction of travel of the moving hearth.
20. The method according to claim 19, where the step of moving such removed magnetic material traverse or along the direction of travel of the moving hearth is performed at a velocity in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute).
21. The method according to claim 20, further comprising the step of:
- causing the removed magnetic material to be impacted against a surface to separate metallic iron material from slag and other associated material.
22. The method according to claim 16, where the step of moving the moving hearth beneath a plow comprises the steps of:
- removing aggregate from the moving hearth over a plow edge and adjacent inclined surface as the hearth moves beneath the plow;
- positioning a brush adjacent to the inclined surface capable of moving aggregate along the surface of the plow; and
- brushing the removed aggregate to a conveying device to remove the removed aggregate.
23. The method according to claim 22, further comprising the steps of:
- positioning at an edge of the inclined surface a classifier for segregating the removed aggregate according to size; and
- returning classified particles smaller than a selected size to the moving hearth.
24. The method according to claim 16, where the step of causing the sweeper to remove at least selected aggregate comprises the step of:
- removing aggregate from the moving hearth using a vacuum device.
25. The method according to claim 16, where the step of causing the sweeper to remove at least selected aggregate comprises the step of:
- intermittently removing material from the hearth.
26. A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
- a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. causing the moving hearth supporting aggregate to move beneath a moving belt positioned between the moving hearth and a magnetic device;
- c. removing magnetic material from the moving hearth by using the magnetic device to remove magnetic material from the aggregate;
- d. then moving the moving hearth with aggregate thereon beneath a plow capable of selectively removing from the hearth a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired; and
- e. moving the hearth beneath a sweeper capable of selective removal of a regulated amount of aggregate from the moving hearth, and causing the sweeper to remove at least selected aggregate from the hearth.
27. The method according to claim 26, further comprising the steps of:
- prior to the step of moving the aggregate beneath the moving belt, cooling the aggregate on the moving hearth in a cooling zone by secondary cooling.
28. The method according to claim 27, where the step of cooling the aggregate by secondary cooling comprises the step of:
- providing coolant tubes in a serpentine configuration adjacent the aggregate on the moving hearth, the coolant tubes being capable of removing heat from the aggregate on the moving hearth.
29. The method according to claim 27, where the step of cooling the aggregate by secondary cooling comprises the step of:
- providing a plurality of coolant tubes capable of circulating coolant therethrough to cool the aggregate on the moving hearth to a temperature of an adjacent atmosphere at or below about 1200° F.
30. The method according to claim 26, further comprising the step of:
- spraying water over the aggregate on the moving hearth to cool the aggregate on the moving hearth by evaporation without substantial water run off to a temperature in the adjacent atmosphere at or below about 800° F.
31. The method according to claim 26, where the step of removing magnetic material from the moving hearth comprises:
- moving such removed magnetic material traverse or along the direction of travel of the moving hearth.
32. The method according to claim 31, where the step of moving such removed magnetic material traverse or along the direction of travel of the moving hearth is performed at a velocity in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute).
33. The method according to claim 32, further comprising the step of:
- causing the removed magnetic removed material to be impacted against a surface to separate metallic iron material from slag and other associated material.
34. The method according to claim 26, where the step of moving the moving hearth beneath a plow comprises the steps of:
- removing aggregate from the moving hearth over a plow edge and adjacent inclined surface as the hearth moves beneath the plow;
- positioning a brush adjacent to the inclined surface and capable of moving aggregate along the surface of the plow; and
- brushing the removed aggregate to a conveying device to remove the removed aggregate.
35. The method according to claim 34, further comprising the steps of:
- positioning at an edge of the inclined surface a classifier for segregating the removed aggregate according to size; and
- returning classified particles smaller than a selected size to the moving hearth.
36. The method according to claim 26, where the step of causing the sweeper to remove at least selected aggregate comprises the step of:
- removing aggregate from the moving hearth using a vacuum device.
37. The method according to claim 26, where the sweeper is capable of intermittently removing material from the hearth.
38. A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
- a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. causing the moving hearth to move beneath a drum positioned transverse to the aggregate on the moving hearth and supporting a belt moving in a continuous loop capable of moving magnetic material counter to the direction of travel of the moving hearth, with a magnetic device being positioned within the drum; and
- c. removing magnetic material from the aggregate, and moving the removed magnetic material for separate processing.
39. The method according to claim 38, further comprising:
- causing a coolant flow through a cooling jacket within the drum.
40. A system for removing metallic iron and associated materials from a moving hearth comprising:
- a. a moving hearth capable of supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. a cooling zone capable of cooling the aggregate on the moving hearth by secondary cooling;
- c. a spray of water capable of cooling the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 800° F. by evaporation without substantial water run off; and
- d. a moving belt positioned between a magnetic device and the moving hearth, the magnetic device being capable of removing magnetic material from the aggregate, and the moving belt being capable of moving the removed magnetic material transverse or along the direction of travel of the moving hearth for separate processing.
41. The system according to claim 40, the secondary cooling comprising:
- coolant tubes in a serpentine configuration adjacent the moving hearth, the coolant tubes being capable of circulating coolant therethrough to remove heat from the aggregate on the moving hearth.
42. The system according to claim 40, the secondary cooling comprising:
- a plurality of coolant tubes capable of circulating coolant therethrough to cool the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 1200° F.
43. The system according to claim 40, where the velocity of the moving belt is in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute).
44. The system according to claim 43, where the moving belt is capable of impacting the removed magnetic material against a surface to separate metallic iron material from slag and other associated material in a direction transverse to the travel of the moving hearth.
45. A system for removing iron from a moving hearth comprising:
- a. a moving hearth comprising a plurality of sections capable of supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. a moving belt positioned between a magnetic device and the moving hearth, the magnetic device being capable of removing magnetic material from the aggregate, and the moving belt being capable of moving the removed magnetic material traverse or along the direction of travel of the moving hearth for separate processing; and
- c. a plow capable of selective removal from the moving hearth a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired.
46. The system according to claim 45, further comprising:
- a sweeper capable of selective removal of a regulated amount of aggregate from the moving hearth when the hearth moves beneath the sweeper.
47. The system according to claim 45, further comprising:
- a cooling zone capable of cooling the aggregate by secondary cooling.
48. The system according to claim 47, the secondary cooling comprising:
- coolant tubes in a serpentine configuration adjacent the moving hearth, the coolant tubes being capable of circulating coolant therethrough to remove heat from the aggregate on the moving hearth
49. The system according to claim 47, the secondary cooling comprising:
- a plurality of coolant tubes capable of circulating coolant therethrough to cool the aggregate on the moving hearth to a temperature of the adjacent atmosphere at or below about 1200° F.
50. The system according to claim 45, further comprising:
- a spray of water capable of cooling the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 800° F. by evaporation without substantial water run off.
51. The system according to claim 45, where the velocity of the moving belt is in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute).
52. The system according to claim 51, where the moving belt is capable of impacting the removed magnetic material against a surface to separate metallic iron material from slag and other associated material in a direction transverse to the travel of the moving hearth.
53. The system according to claim 45, where the plow comprises:
- a plow edge and an adjacent inclined surface positioned to remove aggregate from the moving hearth when the hearth moves beneath the plow; and
- a brush adjacent to the surface capable of moving aggregate along the surface of the plow to a conveying device to remove the removed aggregate.
54. A system according to claim 53, further comprising:
- a classifier capable of segregating the removed aggregate according to size positioned at an edge of the inclined surface and positioned such that classified particles smaller than a selected size return to the moving hearth.
55. A system according to claim 46, where the sweeper comprises a vacuum device capable of removing aggregate from the moving hearth.
56. A system according to claim 46, where the sweeper is capable of removing material from front and rear portions of the moving hearth sections.
57. A system for removing metallic iron and associated materials from a moving hearth comprising:
- a. a moving hearth capable of supporting aggregate comprising metallic iron material, slag, and carbon-bearing material; and
- b. a moving belt positioned between a magnetic device and the moving hearth, with the magnetic device being capable of removing magnetic material from the aggregate; and
- c. a drum being positioned transverse to the aggregate on the moving hearth and supporting the belt moving in a continuous loop capable of moving magnetic material counter to the direction of travel of the moving hearth, the magnetic device being positioned within the drum.
58. The system according to claim 57, where the drum further comprises a cooling jacket capable of receiving a flow of coolant.
59. A system for removing metallic iron and associated materials from a moving hearth comprising:
- a. a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;
- b. a moving belt positioned between a magnetic device and the moving hearth, the moving belt being positioned transverse or along the direction of travel of the hearth, the magnetic device being capable of removing magnetic material from the aggregate and the moving belt being capable of moving the removed magnetic material transverse or along the direction of travel of the moving hearth; and
- c. a collector positioned to receive removed magnetic material from the moving belt.
60. The system according to claim 59, where the velocity of the moving belt is in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute).
61. The system according to claim 59, further comprising:
- an impact plate adjacent to the moving belt, where the moving belt is capable of impacting the metallic iron material against the impact plate to separate metallic iron material from slag and other associated material.
62. A system of removing metallic iron and associated materials from a moving hearth comprising:
- a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material; and
- a plow capable of selective removal from the moving hearth of a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired when the hearth moves beneath the plow.
63. The system according to claim 62, where the plow comprises:
- a plow edge and an adjacent inclined surface positioned to remove aggregate from the moving hearth when the hearth moves beneath the plow; and
- a brush adjacent to the surface capable of moving aggregate along the surface of the plow to a conveying device to remove the removed aggregate.
64. The system according to claim 63, comprising a classifier capable of segregating the removed aggregate according to size positioned at an edge of the inclined surface and positioned such that classified particles smaller than a selected size return to the moving hearth.
65. The system according to claim 63, where the distance between the plow edge and the moving hearth is adjustable.
66. The system according to claim 63, where the brush is a rotary brush positioned above the surface.
67. A system of removing aggregate from a moving hearth comprising:
- a moving hearth comprising a plurality of sections capable of supporting aggregate comprising metallic iron material, slag, and carbon-bearing material; and
- a sweeper capable of selective removal of a regulated amount of aggregate from the moving hearth when the hearth moves beneath the sweeper.
68. A system according to claim 67, where the sweeper comprises a vacuum device capable of pulling aggregate from the moving hearth.
69. A system according to claim 67, where the sweeper removes at least selected aggregate from the moving hearth.
70. A system according to claim 67, where the sweeper removes at least selected aggregate from the front and rear portions of the moving hearth sections.
Type: Application
Filed: Jan 11, 2008
Publication Date: Jan 27, 2011
Applicant: Nu-Iron Technology, LLC (Charlotte, NC)
Inventors: David W. Hendrickson (Coleraine, MN), Rodney L. Bleifuss (Grand Rapids, MN), Raymond P. Mendrola (Pittsburgh, PA), Clayton A. Van Scoy (Butler, PA), Richard A. Kaminski (Pittsburgh, PA), James Donald Bushman (Pittsburgh, PA), Carl Emil Sutherland (Baden, PA)
Application Number: 12/522,867
International Classification: C21B 13/10 (20060101); C22B 3/02 (20060101);