ROTARY HEARTH FURNACE WITH SUBDIVIDED COMBUSTION CHAMBER SPLITTING A SINGLE STREAM OF PROCESS GAS INTO MULTIPLE STREAMS

Abstract

An apparatus and a method for producing direct reduced iron from iron oxide and carbonaceous material is described.

Description

1 Specifications DIRECT REDUCED IN A ROTARY BASE OVEN WITH A SPIRAL-SHAPED COMBUSTION CHAMBER. IRON PRODUCTION 5 CROSS-REFERENCE TO THE RELEVANT APPLICATION The present application is 10, filed on 21 March 2024, and fully included herein by reference. It is claiming priority rights in US Provisional Patent Application No. 63 / 568,396. THE FIELD OF INVENTION The present invention generally relates to rotary-bottom furnaces with a circular gas chamber. 15 BACKGROUND The steel industry converts iron oxides into metallic iron through various processes. A common process is... It is a blast furnace. Alternative processes include DRI (direct reduced iron) or HBI (hot 20 DRI and HBI are direct reduction processes that produce briquetted iron. They are used in electric arc furnaces. They are important components in steel production processes based on direct reduction processes, gas-based or It can be based on solid carbon materials. In gas-based processes, natural gas is used as a reducing agent, as well as coke ovens. Gas or hydrogen can be used. In processes involving carbonaceous materials, reducing agents such as coal and petroleum can be used. The odor can be from charcoal, or other materials with a high carbon content; for example, high 25 These may be some steel mill byproducts, such as dust or sludge coming from the furnace's gas cleaning plant. A particularly interesting option is green iron based on heat-treated wood and / or biomass. The goal is to produce. For processes involving carbonaceous materials, a rotary base kiln (RHF) can be used. Rotary oven The furnace typically includes a rotating circular hearth base, the top of which is lined with refractory material, and this The base is a circular enclosure, sometimes called a gas chamber, which may also be refractory-lined. 30 It rotates inside; additionally, there is a series of burners on the side walls and top ceiling of the furnace. 2 Many conventional metallurgical processes, such as iron and steel production, can contain high levels of iron oxide. It can produce natural by-products and waste materials in the form of dust and mud. These have high monetary value. Therefore, the iron and / or other metals in these materials can be recycled for reuse. It is desirable to obtain [the necessary materials]; however, zinc and lead oxides, or in some cases oil and / or grease, The presence of these and other impurities can make recycling iron difficult and impractical. These 5 These materials may not be recoverable through the traditional iron and steel production process. These materials, a In the direct reduction process, iron in the form of DRI or HBI is removed on one side, and zinc and lead on the other. and other metals can be processed separately for recycling. This type of recycling is rotary-based. It can also be done in the oven. DRI production based on iron ore and / or by-products produces carbon monoxide, hydrogen and / or solids. This can be achieved through a reaction with carbon. Typically, with iron oxide and e.g., coal. A carbonaceous material can be loaded into the furnace and heated. At higher temperatures (e.g., above 900 °C) Coal can react to produce carbon monoxide (C + CO₂ => 2 CO; this is Boudouard's theory). This reaction is known as carbon monoxide reaction (Fe₂O₃ + 3 CO₂ 15), and this carbon monoxide can react with iron oxide (Fe₂O₃ + 3 CO₂ 15). => 2 Fe + 3 CO₂). In a process using carbonaceous material, the Boudouard reaction produces iron oxide. It can produce more carbon monoxide than is needed to reduce metallic iron. This excess carbon Monoxide can be burned in the gas chamber above the furnace to produce the heat necessary for the process. Excess The amount of carbon monoxide may be higher towards the end of the reduction process. On the other hand, the necessary The energy required to produce heat may be more important at the beginning of the process. Carbon monoxide, 20 Carbon dioxide and / or hydrogen gases can be referred to as process gases. Such a process, for example, This can be done in a rotary-based oven. The reduction process carried out in rotary base ovens (“RHF”) is described in the following US patent No. 3,452,972, 3,770,417, 4,597,564, 4,701,214, 5,899,688, and 5,186,741 and 25 in various publications This can be explained. In most cases, the material fed into the RHF can be ground to a very fine particle size and They can then be made into pellets or briquettes. The furnace is mounted on the ceiling or side walls. They can be heated to temperatures of 1200-1400 °C via burners. Pellets or briquettes, rotary oven It can be loaded from one point on the base to the base of the stove and after a little less than one turn can be discharged. Process gas can flow in the counter-current direction to the material and the 30 formed towards the end of the process Excess carbon monoxide can be burned in other parts of the furnace to generate the necessary heat. This type of... One problem that might be encountered in the process is heat transfer; because the input material has a low thermal conductivity. It may have conductivity. Only the top layer of the material is conductive due to the combustion of gas in the gas chamber. 3 It can be exposed to the heat generated, and since heat transfer across the material layer may be very limited, The lower part of the layer may not reach the temperature required for the chemical reactions described above. Additionally, heat flows from the outer surface of the pellets or briquettes towards the center of these pellets or briquettes. The transfer can also be very slow; therefore, the central part of these pellets or briquettes is only low. It reaches a certain level of metallization. Low metallization levels are generally below 5 on the DRI or HBI scale. This means it is of low quality and has little value. In improved rotary base kiln operation, fine iron oxides mixed with carbonaceous material. Feeding the mixture into the oven without clumping has been attempted. In such cases, the mixture of ingredients forms in the oven. It can be loaded from a single point on the inner or outer diameter of the pit. Often referred to as a "plow," these 10 Fixed-mounted mixing devices mix the material from the inner edge to the outer edge of the furnace or from the outer edge to the outer edge. It can be moved towards the inner edge. The movement of the material essentially follows a spiral shape. In the design described above, the start of the process depends on which side is the loading side. It can be on the inside or outside of the furnace. The transformation of iron oxide to metallic iron progresses throughout the furnace and 15 It reaches its maximum level on the opposite side. The process gas flows around the ring-shaped gas chamber. It continues. To carry out such a process economically, it is necessary to use primarily carbon to generate the required heat. It may be necessary to burn the process gas, which consists of carbon monoxide. To obtain good efficiency, the process gas should be 20%. The material may need to flow in the opposite direction. This may not be possible with the method described above; Because as the material moves along the furnace floor, the process gas moves around the perimeter of the furnace. Possible One solution may be described in international application number PCT / CA2011 / 000235. Accordingly, the recycling of direct reduced iron production and iron and steel production by-products is 25%. More efficient and / or cost-effective devices, systems, and methods may be desirable for the transformation. BRIEF DESCRIPTION In various respects, it is more efficient and / or cost-effective for direct reduced iron production. 30 Apparatus, systems, and methods are described. 4 Iron oxide can contain iron ore and residues from iron and steel production. Fine iron. Oxide and carbonaceous material is fed into the furnace of the rotary base kiln, either from a single point on one side of the furnace. The material can be fed continuously, either together or separately from multiple points. The material is a reducing agent. at a sufficient temperature to cause the substance to produce process gas containing carbon monoxide, It can be transported from one side to the other across the furnace by a series of plows; this gas is mixed with iron oxide 5 By reacting, it can form directly reduced iron that can be continuously discharged. The process Some of the gas can be burned to provide the necessary temperature for the reactions. In a gas chamber The partition wall prevents the process gas, which contains carbon monoxide, from escaping the furnace through the furnace chamber. It can direct the gas in the opposite direction of the material flow. Counterflow of gas is necessary for the reduction of iron oxide. can optimize its use and make more efficient use of the heat produced by the combustion of process gas. It can provide. A method for directly producing reduced iron from iron oxide and carbonaceous materials. The apparatus is described. Iron oxide originates from iron ore and / or iron and steel production. waste materials (e.g., broken pellets, rolling mill scale, blast furnace dust and sludge, BOF dust and 15 It may contain sludge, EAF dust, etc. A feed containing iron oxide and a carbonaceous material. The material produces micro-pellets without prior agglomeration or at a minimum level. agglomeration occurs, mainly on one or more of the inner or outer edges of the hearth base of a rotary kiln. It can be fed continuously to several points. One or more plows placed along the furnace hearth, The material is moved around the furnace in a spiral shape, either outwards or inwards, and the material is 20 It is emptied from the mine with a final plow. The reducing agent and iron oxide react. In order to ensure that the temperature is sufficient to directly form reduced iron, the process The gas can be burned in the chamber above the stove. The chamber above the stove is where the gas forms in the layer of material. the flow of process gas, at the point where the heating energy of the combustion of that gas is most required and / or It can be subdivided in such a way that it can be controlled to occur where desired. 25 To ensure efficient use of process gas, the gas can flow against the direction of the material. Bottom of the chamber The vertical walls dividing the room into sections can be arranged in a shape resembling a spiral. The oven Burners and air injection nozzles mounted on the ceiling control the process in different parts of the furnace. It can be configured to provide the specific heating required and / or desired for the reactions. Burners and air nozzles are also used to inject combustion air to burn the process gas. 30 It can be used. For example, additional fuels such as natural gas or fine carbon materials can be used to transfer more heat. They can be added to burners in certain areas where necessary and / or desired. DESCRIPTION OF THE FIGURES The various arrangements described herein, along with the explanations and attached figures presented below, It can be better understood when evaluated. FIGURE 1 shows a schematic view of a rotary-based oven presented according to the present invention. It includes a cross-section of the furnace, which provides a better understanding of the placement of the plows and the lower sections of the gas chamber. It was cut for the purpose of showing. FIGURE 2 shows the top view of the rotary-bottom oven shown in FIGURE 1, with the oven roof cut off. It includes its appearance. 10 Figure 3 shows a cross-sectional view of one side of the rotary-bottom furnace shown in Figure 1. FIGURE 4 shows the shape of the partition wall of the gas chamber of a rotary-bottom furnace presented according to the present invention. an option regarding the location of the loading hopper(s) and the outlet pipe(s). It shows. FIGURE 5 shows the vertical partition wall in the gas chamber of a rotary-bottom furnace presented according to the present invention. It shows a horizontal cross-section of the 3 segments that make it up. FIGURE 6 shows an element of the partition wall of a rotary-bottom oven presented according to the present invention. It shows a vertical cross-section. EXPLANATION 20 The following description details the apparatus, systems, and equipment for the direct production of reduced iron. Specific details have been provided to facilitate a better understanding of various aspects of the methods. However, a technically proficient person would realize that these aspects are not covered in these details and / or here. They will understand that it can be applied even without any undisclosed details. The other 25 in these situations, well-known structures and methods related to the application of various aspects. and / or techniques, making descriptions of other details of various aspects unnecessarily complex. It may not be shown or explained in detail in order to avoid bringing it to light. The present invention relates to the direct production of reduced iron and / or iron and steel production by-products. recycling and / or iron-containing ores, steel mill waste, and other metallurgical processes To recover elemental iron from iron-containing materials, including waste, using metal. 6 More cost-effective and / or efficient apparatus, systems, and for processing oxide fine particles. can provide methods. The present invention enables improved energy efficiency and more efficient combustion of process gas. can provide. 5 The present invention allows for direct reduction at moderate furnace temperatures compared to conventional methods. It could offer an improved method for producing iron more efficiently. The current This invention could allow for more homogeneous heating of different areas of the furnace. The present invention describes the counter-flow motion of feed material and process gases in the combustion chamber. It can provide. The present invention aims to provide the energy / temperature required for the direct reduction of iron oxide. By using the sensible heat and chemical energy of process gas and other volatile substances, energy 15 It can provide an oven with increased efficiency. As explained in more detail below, vertical systems are used to produce reduced iron directly. a generally circular combustion chamber divided by walls, presented according to the present invention A rotary base kiln (RHF) is shown in FIGURES 1 and 2. The kiln includes burners and feed materials. It may contain inlets, and outlets for products and gases. Unprocessed iron ore, pellets 20 fine iron ore such as iron ore recycled from the facility or other iron ore processing plants Iron oxide materials and rolling mill shells and blast furnaces originating from rolling mills. or dust or sludge resulting from waste gas cleaning processes from steel production Waste from iron and steel production facilities, i.e., BOF workshop or electric arc furnace. and reducing agents such as coal, charcoal, bituminous coal, fine coke or petroleum coke, previously 25 can be fed into the furnace without agglomeration (because agglomeration is costly in terms of equipment and labor). (can be intensive and therefore very costly). The materials listed above can be fed from the input(s). and can interact with each other in a reduction reaction in the combustion chamber; then It can exit the chamber directly as reduced iron and gaseous byproducts (iron oxide). materials, reducers and other additives such as lime or limestone, same or different input(s) 30 It can be fed into the furnace via this route. The inside of the combustion chamber can be lined with a refractory material and / or the chamber The walls may include an insulation material and / or cooling elements. The steel shell provides internal insulation. a plate layer, an insulating brick or cast material layer and a high temperature resistant 7 It can be protected with a layer of brick or cast iron material. Between the steel shell and the insulation board (air) Cooling elements (cooled by water or water) can be added. Additionally, better insulation and / or gas can be achieved. To achieve better resistance to degradation caused by aggressive components (i.e., FeO, S). There may be a fourth and a fifth layer of refractory material. The feed placed in the furnace... Materials may include iron oxide materials, reducing agents, and other additives. 5 Feed materials, especially carbonaceous material, are located at different points downstream from the main feed point. This can be achieved at various stages of the process via feeding funnels. Moderate (14-22%) volatile matter. Coal with a volatile matter content can be fed together with iron oxide. High volatile matter content. coal containing 28-36%, bituminous coal or coal with up to 50% higher volatile matter content. Possible charcoal offers more efficient combustion and a better calorific value of volatile matter than 10. It can be fed at a later stage of the process to enable its utilization. Volatile substance, The coal is released as soon as it reaches approximately 450°C. The waste gas exits near the loading hopper. It can be placed. If most of the volatile substance escapes near the feeding point, the burned volatile substance... There may not be enough time for the thermal energy of the materials to be used to heat the cold material. Some or all of the process gas is discharged from the furnace to the other side. It can flow. The rotary base oven (RHF) presented according to the current invention can utilize the thermal energy of the process gas. process gas in order to be used to heat the material and maintain it at the required temperature It can enable reverse flow of material. Process gas is processed with volatile burnt substances from coal. It contains a mixture of CO and CO₂ produced during the process. As discussed above, Boudouard 20 The reaction can produce carbon monoxide, and this substance burns primarily to carbon dioxide. The process gas The outlet may be near the first feed hopper of the material. The outlet of process gas is the process's the process gas produced at the beginning travels a limited distance in the same direction as the feed material. This will allow the gas to flow and thus enable that portion of the process gas to burn more efficiently. It can also be positioned in this way. 25 The reduction of iron oxide is a process involving a reaction between iron oxide materials and reducing agents. This can be achieved through a reduction reaction. Iron oxide material is produced by mixing iron ore with iron and containing impurities or residues resulting from steel production and other metallurgical processes It may contain impurities such as zinc, lead, or cadmium oxides. Iron oxide material, 30 It may contain small pellets or fine granules. The particle size of the fine granules should preferably be 0.1-5 mm. These could include reducing agents such as coal, coke, charcoal, biomass, or petroleum. It may contain solid carbon, such as odorants. Both reducing agents and additives have a carbon content of 0.2-30 mm. 8 It must have a certain granulometry. To produce one ton of DRI, approximately 1.5 tons of iron oxide and 350 kg to 600 kg of reducing agent is required. Additives remove any sulfur that may be present in the reducing agent. It is used for holding. The difference in sulfur content between coal, charcoal and petroleum coke is between 0.1-3%. Since this can vary, the additives may need to be adjusted accordingly. In a laboratory oven. The tests performed examined the granulometry, particle size distribution, purity, and other characteristics of the different materials used. It can determine the optimal balance in terms of characteristics. The ranges of all these characteristics can be very wide. and depends on the availability of resources in the region where the facility is located. With reference to Figures 1, 2, 3, 4 and 5, the present invention generally relates directly to... It may contain a rotary-bottom furnace (1) for producing reduced iron; furnace: a circular combustion 10 a rotary oven (2) located in room (3) containing iron oxide and a reducing agent It contains at least one inlet (15) placed on the furnace to provide the feed material. The feed material can be on the outside or inside of the pit. At least one set of plows is required to move the material into the pit. By moving it towards the opposite side, it can be emptied after numerous turns. (FIGURE) 1-5, option 15 where the feed material is loaded onto the outer diameter of the furnace and discharged from the inner diameter. This shows that the feed material can also be loaded at the inner diameter and unloaded at the outer diameter. At least one set The plow mixes, turns, and conveys the feed material toward the discharge side of the oven. Suddenly If there are multiple plow sets, one or more sets can be used to increase the mixing of the material and To extend the baking time, you can flip and move the material in the opposite direction; this can take 0.3-1.5 hours. It can vary between these. In general, the higher the temperature in the oven, the shorter the cooking time. 20 Depending on the available feed material, temperature can be a factor between energy consumption and efficiency. It can be adjusted to provide optimum results. Different plow sets can mix the feed material, It can be flipped over and also moved from one side of the oven base to the other. Rotating hob. The circular combustion chamber (3) above the base is attached to the ceiling and the material layer is immediately It can be subdivided by a continuous vertical wall (7) extending up to the top. The partition wall, process 25 will allow the gas to flow in the opposite direction to the material, i.e., from the outer diameter to the inner diameter or vice versa. It can be structured in this way. On the stove (2), a circular stove frame (8), a stove heat insulation material and stove frame (8) It may contain a series of arranged refractories (9). 30 The rotary base oven (1) has rails (11) to support the oven (2) and to allow the oven (2) to rotate. It may contain one or more sets of wheels (12). Rails (11) are attached to the bottom of the furnace (2). 9 It can be attached. It can move on rails (11), wheels (12) and the hob (2) is electric, hydraulic, by a drive device containing a pneumatic motor (not shown) It can be rotated. Alternatively, wheels can be attached to the hob frame (8) and mounted on fixed rails. It can move. The rotary base oven (1) prevents gas from escaping from the combustion chamber (3) and / or the combustion chamber (3) It contains a sealing system (10) to reduce and / or prevent the entry of air from the outside. It can. The sealing system (10) includes a circular fixed chamber (30) attached to the furnace frame. This chamber (30) can be filled with an impermeable material (31) such as water or sand. Rotary oven A circular rotating part (32) can be attached to its frame; where the rotating ring (32) is impermeable 10 It is immersed in the material. The rotary base furnace (1) feeds iron oxide and / or carbonaceous material into the furnace's inlet hopper(s). (15) may contain one or more feed conveyors (13). A weir system (14), process It can prevent gas from escaping from the gas chamber or air from entering the furnace. The sluice system (14), upper 15 It may contain an enclosure with two lids placed on top; in this system, the second lid cannot be opened. First, the first lid is closed. Both lids must have a holder to hold the material when the respective lid is closed. A gap may be found. Alternatively, the weir system (14) has a rotating part similar to a revolving gate. It may contain a rotary valve. For example, iron ore, with all or part of the carbonaceous material. Together they can be loaded into the hearth bottom via the funnel (15). A portion of the carbonaceous material, the second and 20 It can be loaded via the third funnels (16). The direction of rotation of the furnace (2) (44) is clockwise, or FIGURE It can be counterclockwise as shown in 4. The inlet funnel (15) can be on any side of the loading side. It can be located in one place. The inlet funnel (15) contains volatile matter in the carbonaceous material. Depending on the amount, the process gas may be closer or further away from the exhaust pipe (20). Volatile If the substance content is higher, the inlet funnel (15) and the process gas exhaust (20) 25 The distance between them can be increased. The combustion chamber (3) contains an outer perimeter wall (5), an inner perimeter wall (4), and a circular ceiling (6). The combustion chamber (3) may contain a circular shape with a U-shaped cross-section. Combustion chamber (3) can be covered with an insulation material and a refractory lining containing one or more layers. 30 The rotary base kiln presented according to the current invention is designed with counterflow, thus adapting to the movement of the material. It can improve the flow of process gas. Improved process gas flow leads to more controlled combustion, process more efficient use of the gas's energy, and better control of temperature in different parts of the furnace. It can be configured in a way that will allow the process gas flow to be controlled by the spiral shape of the combustion chamber. It is well controlled inside. The rotary base kiln has combustion air located along the spiral. It may contain a series of independently controlled injection nozzles. Injections can be administered in different areas. By controlling the amount of combustion air supplied, the temperature of each zone can be controlled independently. It can be done. The circular gas chamber can be subdivided by a vertical wall (7) with a spiral shape. The spiral shape is shown in FIGURE. It can be simplified with interconnected concentric rings as shown in 4. Vertical partition wall (7), It may contain a number of segments (30). A cross-section of such segments (30) is shown in FIGURE 5 (3). 10 The ends of the segments can be configured so that a portion of each end overlaps with the other. Each Segments (30) may contain high temperature resistant refractory material. Segments (30) may also contain: containing at least one cooling pipe (31) covered with insulation material (32) and refractory material (33) The cooling pipe can be U-shaped or in the shape of multiple interconnected U or C letters. The cooling pipe can be attached to an upper flange (35) supporting the segment. Segments (30), furnace 15 It can be supported by a flanged housing (34) attached to the shell plate of its roof (6). The height of the segments, for example, the flanges on the ceiling (34) and the flange (35) supporting the segment (30) It can be adjusted via shims (36) between them. The combustion chamber may contain at least one process gas exhaust pipe (20). The process gas flows back into the material 20 It flows through the spiral-shaped chamber in that direction. The exhaust pipe (20) is mounted at the end of the spiral-shaped chamber. It can be done and the gas and material flow will be 100% counterflow. Alternatively, the pipe (20) outside the room It can be mounted anywhere on the ring. In this case, the volatile coal loaded at the end of the chamber There may be more time for the materials to burn. In this design, the process gas is in the spiral-shaped chamber. It will flow in the same direction along a portion of the first loop; this results in a more efficient 25% distribution of the process gas. This allows it to be used in this way. When carbonaceous material is loaded into a hot furnace, the temperature of the coal increases. As soon as the temperature rises above 400 or 450 °C, volatile substances can escape. The gas containing volatile substances can be efficiently... In order to burn it in some way, the inlet funnel (15) and exhaust pipe (20) of the process gas exhaust pipe through which the furnace will have enough time to burn before exiting the gas chamber It can be structured. In order to make better use of the energy of the volatile matter, the carbonaceous material 30 It can be loaded into the furnace from one or more points. FIGURE 4 shows the possible additional inlet hopper / hoppers (15). The number and location of the inlet hoppers and exhaust pipe, and the supply This may depend on the composition of the material. This choice is mainly based on whether there is an excess or deficiency of volatile matter. 11 whether carbon reacts faster or slower and / or affects the combustion of process gas It can be affected by other factors. In this way, the material remains the same for a quarter or half a cycle. Gas flowing in that direction can improve the utilization of energy in the process gas. The rotary base oven (1) has a series of burners (18) placed on the ceiling (6) to heat the combustion chamber (3). It may contain. For the exterior and interior of the gas chamber, some burners are located inside and / or outside the circular gas chamber. It can be positioned on the wall. Different stages of the process require more or less energy. Because of this, energy requirements vary throughout the spiral-shaped combustion chamber. In order to keep its temperature relatively constant, the burners are set in different areas of the combustion chamber (3). It can provide energy. Burners can use, for example, natural gas, synthetic gas, or any fuel derived from petroleum. or can be operated with combustible gases, liquids, and / or solids such as fine carbon. Carbonaceous material Boudouard process gas produced by volatile substances and occurring in the material layer To burn the excess carbon monoxide produced as a result of the reaction, via burners and / or Additional combustion air or another gas containing oxygen is injected through holes (19) adjacent to the burners. The temperature of the combustion chamber (3) can be between 900-1400 °C, typically 1050-1250 °C. 15 The temperature in and around the feed hopper (15) is the energy required to heat the feed material. It may be lower due to the burners and the combustion of process gas, reducing iron oxide. It can generate enough heat to trigger a reduction reaction of the substance. The combustion air can be preheated or It may not need to be preheated. Preheated combustion air already provides a portion of the required energy, and This reduces fuel consumption. A heat exchanger in the exhaust gas line preheats the combustion air. available. The process gas can flow in the opposite direction (43) of the rotation of the rotary kiln (44). Counterflow process gas, as described above It can be used throughout the furnace to the extent necessary or useful as described. The exhaust pipe (21) By repositioning it to a location similar to its original position, a portion of the process gas flows towards the rotary kiln at 25°. It can flow and improve the utilization of the energy of the process gas that flows back as described above. Each ring of the spiral-shaped chamber can have 2-12 burners. Alternatively, there can be 1-10, 11-20 burners per ring. or there may be a maximum of 20 injection nozzles, such as 1-20. The area around each burner is adjacent to the one next to it. It can be defined as a distinct zone along with the nozzles. The temperature in each zone is determined by the burner and / or... The amount of oxygen injected from the injection nozzles of the region can be regulated independently. 30 It is measurable and controllable. The temperature in each region can be reduced to the entire region or to an adjacent region. It can be adjusted to be equal to the top. Furthermore, it can achieve the desired process reactions in a specific region. It can be adjusted in different ways to do so. The partition wall (7), the position of the supply tunnel / tunnels (15) and 12 The process, along with the location of the exhaust pipe(s), is designed to ensure optimum process efficiency. It can be configured in a way that allows the combustion of the gas to be controlled. The gas and the material... Counterflow, the channeling of carbon monoxide gas produced during the process to areas where energy is needed. It can be configured to allow combustion. Carbon monoxide is produced during the process. Controlling the combustion of the gas in this way will reduce the need for additional fuel and thus shorten the process to 5. This will make it more energy efficient. This control is better compared to traditional methods. It can provide an efficient reaction process. For comparison, it is operated with conventional RHF. A direct reduction rotary base furnace, for example, produces approximately 200 Nm³ of natural gas per ton of DRI. This may require additional fuel. With efficient use of process gas, fuel consumption can be reduced to approximately zero. It can be downloaded. The waste gas can exit the furnace through the waste gas pipes (20). Process gas funnel and 10 The tube (20) may be cooled and / or refractory coated. A rotary base oven (1) may contain at least one arm (23) mounted on the hob (2). Each arm (23) can extend along the interior of the combustion chamber (3) and across the width of the surface of the hearth (2). The perimeter wall (4) and the inner perimeter wall (5) can support one or more arms (23). FIGURE 2 shows 15 of these. It shows a rotary-based oven with eight arms (23). The arms (23) radially around the hearth (2). They may be spaced out. A series of arms (23) may be placed at equal intervals around the hearth (2) or It may not be. The distance between successive arms may increase, decrease, or remain largely the same. It can stay. The rotary base oven (1) may contain at least one set of plows (24) attached to the arm (23). The sets of plows (24) The number of arms is equal to the number of (23). Plows (24) can extend towards the surface of the pit (2). Plows (24) to adjust the thickness of the material resting on the surface of the furnace (2) and / or thermal expansion In order to ensure that the plows (24) do not obstruct the turning of the quarry (2), support The height of the hob (2) can be adjusted by adjusting the height of its arms (23). 25 Plows (24) can turn the material (25) on the hearth (2) over and from one side of the hearth to the other. can carry it to the side. After turning the furnace (2) a few turns, the material is carried by an extended plow (26) It can be emptied from the furnace (2) by means of. FIGURE 4 shows the material movement in a furnace with 4 sets of arms. It shows an example. Plows (24) turn the feed material over and move sideways along the kiln floor. To do this, the lever (23) which is radial to the oven base surface must be at an angle greater than 0° and less than 90°. It is possible. Typically, the angle of the plow relative to the arm should be between 15° and 45°. Adjacent plows (24) 13 The distance between them may be the same or different. When a larger number of arms and plow sets are used, To move the material in the opposite direction, one or more sets of plows can be angled in the opposite direction. This allows It can improve stirring and allow the ingredients to be turned more frequently on the stove; same This can extend the time the material remains on the forge. Plows feed when the forge is rotating. It can turn, move, and mix its ingredients. 5 The arms and plows can be cooled by a coolant circulating through them. The coolant can be a gas or It can contain a liquid such as water, air, and nitrogen. A mechanical pump transports the coolant through a pipe. You can make it flow through the arm by circulating it. The rotary base oven (1) has at least one fixed scraper (not shown) located on one inner edge of the oven (2) and may include at least one fixed scraper located on one of the outer edges of the furnace (2). The scrapers remove the material. It can hold the material on the surface of the stove and / or prevent the material from falling off the stove surface, or prevent it from falling. It can reduce the amount of material. The present invention describes a method for the direct production of reduced iron in a rotary-bottom furnace. It can. A feed material containing iron oxide can produce a carbonaceous material at a temperature of 900-1300 °C. It can react with carbonaceous materials, such as coal, charcoal, and coke, to produce metallic iron. It may contain coal, petroleum coke, oil, grease, plastic waste, or wood. It may also be feed. Volatile components in the material, such as zinc, lead, chlorine, and alkalis, can be evaporated and removed with the waste gas. They can be discharged together. The turning and movement of the feed material presented according to the present invention. The mixing and / or stirring of the material layer (25) improves heat transfer and CO formation. (Boudouard reaction) can improve it. As a result, the CO / CO₂ ratio in the material layer can be improved. The material can be raised sufficiently to cause the reduction of iron oxide. A CO concentration of over 60% can be achieved in the layer. The CO escaping from the material layer is 25 The feed material can be burned in the gas chamber above it. The combustion of CO generated during the process, It can generate enough heat to initiate the reaction process. Burners and air injection nozzles, In order to prevent a decrease in the CO concentration in the material layer, the combustion of CO so that it takes place in the upper part of the combustion chamber, that is, far enough away from the layer of material. It can be placed at an angle. 30 The direct method of producing reduced iron generally involves placing iron oxide in a rotary-bottom furnace. loading of the material and a reducing agent, the material being transported by means of at least one set of plows. 14 the movement and simultaneously the inner surface of each piece of iron oxide material. to distribute heat evenly to its core and to produce reduced iron directly. It may involve turning the material multiple times. Process gas, in a vertical compartment in the gas chamber. Guided by the wall, the material can flow in the combustion chamber in the opposite direction of its movement. The method involves rotating the reduced iron directly after completing several turns of the rotary furnace. 5 This may include draining it from the stove. The reducing agent can be mixed with iron oxide material and used together with iron oxide material. It can be fed into the furnace. The reducing agent may not be mixed with iron oxide material and a different input is required. It can be fed into the rotary kiln via this route. The feed material flows in the opposite direction of the reducing gas flow. It can progress. The iron oxide material is preheated separately from the reducing agent before being loaded into the furnace. It can be contained. The sensible heat of the process gas exiting the furnace is applied to the iron oxide material on the furnace. It can be used to preheat the area just before dropping. 15 The plows can extend outwards from the arms towards the furnace surface. Containing iron oxide material. A feed material can be placed on the furnace surface and plowed by the plows as the furnace rotates. It can be mixed with a reducing agent. Each group of plows can move the material in the same direction. Some plow groups have 20 plows where all plows together continue to move the material in the desired direction. During this process, the feed material can be reversed and transported in the opposite direction. Moving the material in the opposite direction, This can extend the residence time of the material on the furnace surface. The present invention feeds the material while the furnace is rotating. increasing heat transfer and reaction efficiency by repeatedly rotating and moving the material Thanks to this, it can be more efficient than traditional methods. The present invention also utilizes process gas. By enabling the feed material to flow in the opposite direction, it is more efficient than traditional methods. 25 It is possible. The degree of metallization should be at least 75%, 80%, 85%, 90%, 92%, 95%, 98% or more. For example, it can be 95-98%. The degree of metallization of DRI refers to the metallicity of iron oxide during reduction. It could be the degree of conversion to iron. This is the ratio of the metallic iron mass to the total iron mass. It can be defined as the percentage obtained by dividing by two. The method involves continuously feeding iron oxide-containing material into the furnace, while the furnace base is constantly being heated. and the oven base to be rotated and mixed and turned on the oven base the presence of plows laid along the length, at least in the form of solid or liquid carbonaceous material. a reducing agent to iron oxide, either together with iron oxide or through different feed hoppers the addition of the reducing agent by stirring it together with iron oxide and mixing it with iron oxide, The process essentially involves creating a mixture of materials containing iron oxide, impurities, and a reducing agent, then heating it. to increase transfer and reaction efficiency, the material mixture is turned several times; to ensure that the process gas and feed material flow in counterflow through the furnace chamber, iron 5 reacts carbon dioxide, which is produced as a result of the reduction reaction of oxide, with carbonaceous material. by introducing carbon monoxide as a reducing gas, and combining the reducing gas with metal oxides directly forming reduced iron by reacting it, from the ceiling of the furnace or from the inside or outside a gas supply containing oxygen through its wall, burning the process gas with oxygen to produce the heat required for the process to produce, evaporate volatile metals such as zinc and lead, alkalis, chlorine and other impurities, 10 removing volatile substances from the top of the furnace along with the waste gas, and after the furnace has rotated a few times This involves recovering directly reduced iron along with the residues of reducing agents. can. The present invention describes a rotary-bottom oven with mixing devices running along the oven base, 15 It may involve a process that is carried out. The feed material is iron oxide and carbonaceous material. It may contain pellets. Unlike traditional ovens, the feed material is pelletized. or briquetting may not be necessary. Direct processing is carried out in traditional rotary-base kilns. In reduction processes, feed material can be loaded from any point on the furnace base and It can be unloaded in slightly less than one turn. The material layer is 20 during the entire turn. It may not be moved. The feed material agglomerates to achieve higher heat dissipation. It is possible. Agglomerating the feed material can be a costly process. According to the present invention... In the presented method, the material is designed so that heat diffusion contacts the entire layer or a large portion of it. It can be rotated multiple times in such a way that the feed material is placed on one or more of that oven bases. It can be loaded onto the oven base from multiple points. A series of fixed arms located on the hob provide feed 25 A series of plows, each designed to gently push the material to the side while mixing it. It can support this. After a few turns, directly reduced iron from the feed material. It can be produced and discharged from the furnace. The feed material on the stove can be continuously stirred and turned; thus, 30 Compared to traditional methods that do not mix or turn the material, it reduces the heat in the feed material. The transfer is improved. The temperature in the furnace is lower (1000-) compared to conventional processes (1250-1350 °C). It could be 1200 °C or just above the approximate 900 °C temperature required for process reactions. 16 It could be a little higher. Continuous stirring and alternating turning enhance the process reactions. It improves heat exchange in a way that supports; that is, on the one hand, carbon dioxide and carbon from The Boudouard reaction is used to produce carbon monoxide, while another reaction is used to produce metallic iron. Carbon monoxide reacts with metal oxide. Intensive stirring ensures that the material produced... By enabling better contact with gases, it facilitates heat transfer and also the reactions. 5 It increases its concentration. As a result of improved reactions, a greater amount of carbon monoxide is produced. can be produced. The excess carbon monoxide produced reacts with the injected oxygen-containing gas. The furnace can generate a significant amount of heat. The partition wall in the gas chamber allows the excess combustible gas to transfer its heat. It can be configured to be burned in the furnace areas where it is required. This allows for more efficient use of process gas. Its use can reduce the external energy consumption of the process. 10 The apparatus, systems, and methods presented in accordance with the current invention offer superior performance compared to traditional techniques for iron. It can enable more efficient reduction of the oxide. The present invention offers the following advantages: It can provide one or more of the following: no need to prepare the feed material; in the oven High heat transfer through continuous mixing and turning of the feed material; the furnace's different 15 High energy efficiency through controlled combustion of process gas in these regions; lower furnace capacity. the ability to produce highly metallized iron at high temperatures; and controlling the flow of process gas in the furnace Control of process gas combustion in different regions and with combustion air and / or iron oxide Improved energy efficiency through the use of sensible heat for preheating the material. Each of the features and examples described above, and combinations thereof, constitute a basis for the present invention. It can be said that it falls within the scope of the following non-limiting features. Therefore, the present invention has the following non-limiting characteristics. It focuses on: Feature (1) A rotary base furnace for producing directly reduced iron, containing 25 It consists of: a rotary oven with a combustion chamber divided into circular subdivisions; iron oxide and a One or more feed hoppers for delivering feed material containing reducing agent; and a set of plows for turning and moving the feed material across the ridge. Feature (2) is a rotary base oven offered in accordance with Feature 1, where the gas chamber contains 30 process gases. with a vertical wall that allows the flow to be controlled and to be in the opposite direction of the material flow It is divided. 17 Feature (3) The rotary base oven offered according to Features 1 and 2, where the compartment in the gas chamber Its wall has a shape that is close to a spiral. Feature (4) is a rotary base oven offered according to Feature 1-3, where the gas chamber is different The cross-sectional area of ​​the regions has been increased in proportion to the volume of process gas. 5 Feature (5) is a rotary base oven offered according to Features 1-4, where the feed material is a or the kiln is fed from several points and as the rotary kiln rotates, multiple, e.g., several sets of stationary plows are used. It is moved from one side of the burner to the other and rotated many times. Feature (6) is a rotary base oven offered according to Feature 1-5, where the temperature of the combustion chamber is approximately 900 °C to approximately 1300 °C; for example, approximately 900-1200 °C, approximately 900-1100 °C, or It is approximately in the range of 900-1000 °C. Feature (7) It is a rotary base oven offered according to Feature 1-6, with approximately more than 90%, e.g. 15 Characterized by a metallization degree of 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%. It is done. Feature (8) Directly reduced using the rotary base oven presented according to Feature 1-7 It is a method for producing iron, where the rotary furnace consists of a circular combustion chamber divided into sub-sections. It revolves around; the method involves: iron oxide and a reducing agent. The feeding of the material into the rotating furnace from a single point or from several points; feeding The material is gradually turned and moved; and the gas flows in the counter-flow to the material. controlling the flow. Feature (9) is the method presented according to Feature 8, where the feed material is in at least one, e.g. several sets This involves moving the material from one side of the pit to the other using a plow. Feature (10) The method presented according to Features 8 and 9, after a few revolutions of the rotary oven, the final 30 involves the direct discharge of reduced iron from the rotary furnace by means of an extended plow. does. 18 Feature (11) The method presented according to Feature 8-10, where the process gas is the material in the furnace in the opposite direction of its movement, from one side of the hearth to the other in the divided circular gas chamber. It involves draining. Feature (12) The method presented according to Feature 8-11, where the rotary base oven is a single circular 5 It includes a rotating grill. Feature (13) A rotary base furnace for producing directly reduced iron, which includes: It consists of: a rotary oven in a circular combustion chamber; containing iron oxide and a reducing agent. one or more inlet hoppers to deliver the feed material; and feed the material into 10 a set of plows for turning and moving the material from one side of the furnace to the other; here, the process The flow of gas is controlled by a partition wall in the circular gas chamber, where the process The gas flows over the burner in the opposite direction to the movement of the feed material. Feature (14) is a rotary base oven offered according to Feature 13, where the partition wall in the gas chamber is 15 It is spiral or helical in shape. Feature (15) Rotary base oven offered according to Feature 13 or 14, where spiral shaped compartment The wall comprises a series of interconnected concentric rings. Feature (16) is a rotary base oven offered according to Feature 13-15, where the partition wall, It contains a gap towards the rotary oven large enough to allow the material to pass through. Feature (17) is a rotary base oven offered according to Features 13-16, where the partition wall is a series of separate It contains segment 25. Feature (18) is a rotary base oven offered according to Features 13-17, where the partition wall This segment contains solid refractory material. Feature (19) is a rotary base oven offered according to Feature 13-18, where the partition wall is 30 The segments contain a tube that allows cooling with a circulating liquid or gaseous fluid. does. 19 Feature (20) Rotary base furnace offered according to Feature 13-19, where carbon reducer Iron oxide mixed with the substance is fed into the furnace from a point on the inner or outer diameter of the rotary furnace. Feature (21) Rotary base furnace offered according to Feature 13-20, where iron oxide alone or is fed with a reducing agent, and part or all of the reducing agent, one or more of 5 Excess is fed separately into the rotary furnace via a secondary hopper. Feature (22) is a rotary base oven offered in accordance with Features 13-21, where there is at least one secondary hopper. The process gas produced by the reducing agent, which is fed through, passes between the partition walls. or flows through multiple additional curves. 10 Feature (23) Rotary base oven offered according to Feature 13-22, where secondary hopper(s) The process gas produced by the reducing agent, which is fed through, is burned in additional coils and The process gas is used to heat the iron oxide before it exits the gas chamber at the final bend. Feature (24) is a rotary base oven offered according to Features 13-23, where the burners and air The nozzles are positioned around the different curves of the combustion chamber. Feature (25) Rotary base oven offered according to Feature 13-24, where process gas, spiral shaped It is expelled through an exhaust pipe at the final bend of the gas chamber. 20 Feature (26) is a rotary base oven offered according to Feature 13-25, where the temperature of the combustion chamber is approximately 800 °C to approximately 1300 °C, for example, approximately 800-1200 °C, approximately 800-1100 °C, approximately It is between 900-1000 °C, or approximately 800-900 °C. Feature (27) By using a rotary base oven that has any of the above features It is a method for directly producing reduced iron, where the rotary furnace is divided into sub-sections. It rotates within a separated circular combustion chamber; the method involves: iron oxide and a The feed material containing the reducing agent is fed separately through one or more funnels. or together, feeding the material into the rotating kiln; feeding the material into the kiln with one or more sets of plows 30 Turning it from one side to the other and moving it; dividing it to control the temperature in each zone. Combustion of process gas produced by the reducing agent in the combustion chamber. Feature (28) is the method presented according to Feature 27, and in the last bend of the spiral-shaped gas chamber there is a It contains process gas exhaust. Feature (29) is the method presented according to Features 27 and 28, and the efficiency of process gas combustion. It includes alternative gas exhaust pipe locations that increase efficiency. 5 Feature (30) The method presented according to Feature 27-29, and the rotary oven rotates after a few revolutions. It involves the direct discharge of reduced iron from the furnace. Feature (31) The method presented according to Feature 27-30, 10 in the opposite direction of the movement of the material. It involves a process gas flow throughout the rotary kiln. All documents referenced herein are included in this document by way of reference; however, this inclusion does not constitute an endorsement. the material provided does not contradict the existing definitions, statements, or other documents stated herein. This applies to all extent. Any meaning or definition of a term in this document, including by reference, is included within 15 To the extent that it contradicts any meaning or definition of the same term in a document, that document contains that The meaning or definition assigned to the term will be valid. Any reference to a document in question will be considered valid. This should not be interpreted as meaning that the document is considered to be a previous technical document in terms of the current application. Specific apparatus, systems, and methods for the direct production of reduced iron. Although the regulations have been shown and explained, for those skilled in the field, the essence of the invention and It is clear that various other changes and modifications can be made without deviating from the scope. In technology... Experts believe that the specific apparatus, systems, and methods described here are alternatives. countless equivalents including variants, additions, deletions, modifications and substitutions will be able to notice or detect it without using more than routine experiments. Therefore, attached 25 The current application, including the requests, encompasses all such requests within the scope of the current application. It aims to include changes and modifications.

Claims

21 REQUESTS 1. A rotary base furnace (1) for producing directly reduced iron, which includes the following: does: a rotary oven (2) inside a circular combustion chamber (3); 5 to provide a feed material containing iron oxide and a reducing agent (25) one or more inlet funnels for (15); to turn the feed material (25) and move it from one side of the furnace (2) to the other side a set of plows (24); Here the flow of process gas (43), a partition wall (7) inside the circular gas chamber (3) 10 It is controlled by, and The process gas flows through the furnace (2) in the opposite direction to the feed material (25).

2. The rotary base furnace (1) submitted in accordance with claim 1, where the partition wall inside the gas chamber (3) (7) has a shape resembling a spiral or a helix. 15 3. The rotary base oven (1) is offered according to any of the previous requests, where spiral The shaped partition wall (7) consists of several concentric rings connected to each other.

4. The rotary base oven (1) offered according to any of the previous requests, where compartment 20 a wall (7) large enough to allow material (25) to pass through, opening into the rotary oven (2). It has a gap.

5. The rotary base oven (1) is offered according to any of the previous requests, where the compartment The wall (7) consists of a series of separate segments (30). 25 6. The rotary base oven (1) is offered according to any of the previous requests, where the compartment The segments (30) of its wall (7) are made of solid refractory material (33).

7. The rotary base oven (1) offered according to any of the previous requests, where compartment 30 segments (30) of its wall (7) allow cooling with a circulating liquid or gaseous fluid. It contains a tube (31) that recognizes. 22 8. The rotary base kiln (1) is offered according to any of the previous requests, where carbonaceous Iron oxide mixed with reducing agent, in an inner or outer diameter of the rotary oven (2) It is fed from point (2) to the furnace.

9. The rotary base oven (1) is offered according to any of the previous requests, where iron 5 The oxide is fed alone or together with some of the reducing agent, and the reducing agent... Part or all of the material is fed into the rotary furnace via one or more secondary funnels (16). (2) are fed separately.

10. The rotary base oven (1) is offered in accordance with any of the previous requests, where the secondary 10 The process gas produced by the reducing agent fed through the funnel(s) (16), compartment It flows through one or more additional bends between the wall (7).

11. The rotary base oven (1) is offered in accordance with any of the previous requests, where the secondary The process gas produced by the reducing agent fed through the funnel(s) (16) is an additional 15 can be burned in the bends and process gas exits the gas chamber (3) before the iron can be burned in the last bend. It can be used more effectively for heating the oxide.

12. The rotary base oven (1) is offered according to any of the previous requests, where combustion Burners (18) and air nozzles (19) all around the different curves of the room (3) 20 It has been placed.

13. The rotary base oven (1) is offered according to any of the previous requests, where the process the gas exits through an exhaust pipe (20) at the last bend of the spiral-shaped gas chamber (3). is removed. 25 14. The rotary base oven (1) is offered according to any of the previous requests, where combustion takes place. Room (3) has a temperature between approximately 800 °C and approximately 1300 °C.

15. Using the rotary base oven (1) provided according to any of the previous requests, directly 30 It is a method for producing reduced iron, where the rotary furnace (2) is divided into sub-sections. It rotates inside a separate circular combustion chamber (3), the method includes the following: 23 feed material containing iron oxide and a reducing agent (25), one or through several funnels (15, 16), separately or together, to the rotating furnace (2); feed material (25), one or several sets of plows (24) from one side of the pit (2) turning it to the other side and moving it; and To control the temperature in each region, in the subdivided combustion chamber (3) 5 Combustion of the process gas produced by the reducing agent.

16. The method presented in accordance with claim 15 is a process in the final bend of the spiral-shaped gas chamber (3). gas contains exhaust (20).

17. The method presented in accordance with claims 15 and 16 provides higher efficiency in the combustion of process gas. It includes alternative gas exhaust pipe locations (21) that provide.

18. The method presented according to claims 15 to 17, after the rotary oven (2) has rotated a few turns, This involves the discharge of the directly reduced iron from the rotary furnace (2). 15 19. İstem 15 ila 18’e göre sunulan yöntem olup, malzemenin (25) bir hareket yönünün tersi yönde döner ocak (2) üzerinden geçen bir proses gazı akışı (43) ihtiva eder. 18 CLAIMS 1. A rotary hearth furnace to produce direct reduced iron comprising: a rotary hearth within an annular combustion chamber; one or more inlet funnels to provide a feed material comprising iron oxide and a reducing agent; 5 a plurality of sets of ploughs to turn over and move the feed material from one side of the hearth to the opposite side; wherein the flow of the process gas is controlled by a subdividing wall in the annular gas chamber, and wherein the process gas flows in the opposite direction to the feed material across the 10 hearth.

2. The rotary hearth furnace of claim 1, wherein the subdividing wall in the gas chamber has a shape resembling to a spiral or a coil.

3. The rotary hearth furnace of any of the foregoing claims, wherein the spiral shaped subdividing wall is composed of several concentric rings that are interconnected. 15 4. The rotary hearth furnace of any of the foregoing claims, wherein the subdividing wall has a gap to the rotating hearth big enough to let the material pas.

5. The rotary hearth furnace of any of the foregoing claims, wherein the subdividing wall is composed of a series of individual segments.

6. The rotary hearth furnace of any of the foregoing claims, wherein the segments of the 20 dividing wall are made of solid refractory material.

7. The rotary hearth furnace of any of the foregoing claims, wherein the segments of the dividing wall comprise a pipe that allows cooling with a circulating liquid or gaseous fluid.

8. The rotary hearth furnace of any of the foregoing claims, wherein the iron oxide mixed with the carbonous reducing agent is fed onto the hearth at one point on either the inner or outer 25 diameter of the rotating hearth 9. The rotary hearth furnace of any of the foregoing claims, wherein the iron oxide is fed alone or with a part of the reducing agent and part or all of the reducing agent is fed separately through one or multiple secondary funnels onto the rotating hearth. 19 10. The rotary hearth furnace of any of the foregoing claims, wherein the process gas generated by the reducing agent that is charged through the secondary funnel(s) flows one or multiple extra windings between the subdividing wall.

11. The rotary hearth furnace of any of the foregoing claims, wherein the process gas generated by the reducing agent that is charged through the secondary funnel(s) can be combusted in the 5 extra windings and be better used to heat the iron oxide before the process gas exits the gas chamber from the last winding.

12. The rotary hearth furnace of any of the foregoing claims, wherein burners and air nozzles are installed all around the different windings of the combustion chamber.

13. The rotary hearth furnace of any of the foregoing claims, wherein the process gas is 10 extracted through an exhaust pipe in the last winding of the spiral shaped gas chamber.

14. The rotary hearth furnace of any of the foregoing claims, wherein the combustion chamber has a temperature from about 800°C to about 1300°C.

15. A method to produce direct reduced iron using the rotary hearth furnace of any of the foregoing claims, wherein the rotary hearth is rotating within the subdivided annular 15 combustion chamber, the method comprising: providing the feed material comprising iron oxide and a reducing agent through one or several funnels onto the rotating hearth, separate or together; turning over and moving the feed material with one or several sets of ploughs from one side of the hearth to the opposite side; and 20 burning the process gas generated by the reducing agent in the subdivided combustion to control the temperature in each zone; 16. The method of claim 15 comprising a process gas exhaust in the last winding of the spiral shaped gas chamber 17. The method of claim 15 and 16 comprising alternative gas exhaust pipe positions that allow 25 a better efficiency of the process gas combustion.

18. The method of claim 15 to 17 comprising discharging the direct reduced iron from the rotating hearth after several revolutions of the rotating hearth.

19. The method of claim 15 to 18 comprising a process gas flow across the rotating hearth in a direction opposed to a direction of the material. 30

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