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WO2004067784A1 - Procede pour produire de l'eponge de fer et de la poudre de fer reduite, eponge de fer et dispositif de charge - Google Patents

Procede pour produire de l'eponge de fer et de la poudre de fer reduite, eponge de fer et dispositif de charge Download PDF

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Publication number
WO2004067784A1
WO2004067784A1 PCT/JP2004/000866 JP2004000866W WO2004067784A1 WO 2004067784 A1 WO2004067784 A1 WO 2004067784A1 JP 2004000866 W JP2004000866 W JP 2004000866W WO 2004067784 A1 WO2004067784 A1 WO 2004067784A1
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WO
WIPO (PCT)
Prior art keywords
powder
reducing agent
iron oxide
iron
amount
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2004/000866
Other languages
English (en)
Japanese (ja)
Inventor
Yoshitomo Suzuki
Akio Sonobe
Takashi Kuroki
Yasuhiko Sakaguchi
Hiroshi Itaya
Yotsuo Misumi
Isao Funatsu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
Original Assignee
JFE Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2003286047A external-priority patent/JP4329444B2/ja
Application filed by JFE Steel Corp filed Critical JFE Steel Corp
Priority to US10/508,381 priority Critical patent/US20050193862A1/en
Publication of WO2004067784A1 publication Critical patent/WO2004067784A1/fr
Priority to SE0402286A priority patent/SE528252C2/sv
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/0025—Charging or loading melting furnaces with material in the solid state
    • F27D3/003—Charging laterally, e.g. with a charging box
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/0033—Charging; Discharging; Manipulation of charge charging of particulate material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/08—Screw feeders; Screw dischargers

Definitions

  • the present invention relates to a method for producing sponge iron used as a raw material for producing iron powder, and a method for producing reduced iron powder using sponge iron produced by the method.
  • the reduced iron powder is used not only as powder but also as a raw material for sintered products such as mechanical parts and magnetic materials.
  • the present invention also relates to an apparatus for charging a raw material for producing sponge iron used in the method for producing sponge iron, and a high-purity sponge iron that can be produced by the method.
  • the charge of the raw material into the reaction vessel is conventionally referred to as charging the raw material (however, translated into charge in the English translation). Words such as “filling” and “filling device” are mainly used. Background art
  • FIGS. 1A and 1B A typical method for producing sponge iron is shown in FIGS. 1A and 1B.
  • FIG. 1A is a cross-sectional view showing the state of filling of the raw material in the container
  • FIG. 1B is a horizontal cross-sectional view thereof.
  • iron oxide powder 2 and reducing agent powder 3 are concentrically placed in a cylindrical refractory reaction vessel 1 (sagar) with a lid attached to the lower surface. Then, the whole container is heated (indirect heating) to a temperature of 1050 to 1200 using a tunnel furnace or the like. By the heating in the above period, the iron oxide powder 2 in the reaction vessel 1 is reduced (coarsely reduced) and sintered together to form sponge-like metallic iron, that is, sponge iron.
  • the iron oxide powder 2 powder obtained by pulverizing a mill scale, iron ore powder, or the like is used.
  • the reducing agent powder 3 coke powder / coal powder or the like is used. Note that lime powder or the like is added to the reducing agent powder 3 as needed.
  • the reaction reduces iron oxide and generates co 2 (carbon dioxide) gas. Further, the co 2 gas diffuses partially through the reduced iron oxide layer, reaches the reducing agent layer again, and converts carbon into CO gas by the reaction of equation (1) in the layer. Then, CO gas this that generated diffuses into the re Pi iron oxide layer, causing a reaction of iron oxide and (2) of unreduced, iron generates the co 2 gas while generate.
  • the iron oxide powder 2 filled therein is reduced to iron powder by repeating the reaction of the equations (1) and (2) at regular intervals. Simultaneously with this reduction reaction, sintering of the reduced iron proceeds to form cylindrical sponge iron (sintered body).
  • Figure 2 shows the appearance of sponge iron obtained by the conventional technology (the lower part is omitted).
  • carbon amount Z oxygen amount (molar ratio) The number of moles of carbon atoms in the reducing agent / the number of moles of oxygen atoms in the iron oxide. Disclosure of the invention
  • the diffusion of the CO gas and co 2 gas generated in the reaction vessel 1 into the layers of the iron oxide powder 2 and the reducing agent powder 3 is a main factor that controls the progress of the reduction reaction. It is considered a factor.
  • the diffusion distance of CO Gas and co 2 gas greatly there has been a problem that it takes a long time required for the reduction.
  • the reaction efficiency gas utilization efficiency
  • the time required from the charging of raw materials to the extraction of the product is reduced. It takes days and leads to reduced productivity.
  • the heating energy consumption required for the reduction is significantly increased.
  • the combination of the thickness of the layer of iron oxide powder 2 and the reduction time that maximizes the production amount is uniquely determined, and not only is the production amount limited, but also the degree of freedom in adjusting the production amount is high. There was a problem of being small.
  • the CO gas generated by the above reaction tends to flow through the lower density layer of the reducing agent powder 3 and flow out of the reaction vessel 1. is there. Therefore, the CO gas does not efficiently contribute to the reduction reaction.
  • the reducing agent powder 3 needs to be excessively filled between the reaction vessel 1 and the iron oxide powder 2 or inside the cylindrical iron oxide layer so that the layer of the iron oxide powder 2 does not collapse in the firing step.
  • the conventional method requires a large amount of the reducing agent powder 3 in a molar ratio of 2.0 or more, and has a problem in that the basic unit of the reducing agent is poor.
  • an object of the present invention is to advantageously solve the above-described various problems of the related art. That is, an object of the present invention is to propose a method for producing sponge iron which has high productivity and whose production amount can be easily adjusted.
  • Another object of the present invention is to propose a device for filling a raw material into a reaction vessel, which is advantageously used in carrying out the above-mentioned production method.
  • a first aspect of the present invention provides a filling step of filling an oxidized iron powder and a reducing agent powder in a reaction vessel, and heating the iron oxide powder in the reaction vessel by heating from outside the reaction vessel.
  • a layer made of the reducing agent powder is formed on the container side surface (referred to as an outer peripheral portion) and a vertical central axis portion in the reaction container, and the remaining portion (referred to as an intermediate portion) excluding the layer is formed. Filling to form said alternating and spiral layers.
  • the outer peripheral portion and the central shaft portion correspond to the peripheral portion and the central portion, respectively, in the plan sectional view of the container.
  • the middle part is preferably cylindrical or cylindrical.
  • the vertical central axis is the axis of the cylinder.
  • iron oxide powder at least one powder selected from iron ore, mill scale, and oxidized iron powder recovered from the pickling waste liquid is used.
  • At least one powder selected from coke, charcoal and coal is used.
  • a carbon dioxide gas generating source is added to the reducing agent powder.
  • Lime as a source of carbon dioxide Stone is particularly suitable.
  • the reducing agent powder to be filled is a mixture of the reducing agent powder and the powder of the carbon dioxide gas generation source.
  • the heating temperature in the reduction step is not less than 1000 ° C and not more than 1300 ° C.
  • the layer thickness of the iron oxide powder layer and the layer of the reducing agent powder are variably controlled.
  • the variable control means that a different layer thickness can be set in at least one of the layers for each reaction vessel, and (1) the thickness of at least one of the layers is changed depending on the position in the reaction vessel. Obtaining, including both meanings.
  • the amount of the iron oxide powder in the reaction vessel or the amount of the reducing agent powder is determined by changing the amount of carbon contained in the reducing agent powder with respect to the amount of oxygen contained in the iron oxide powder. Should be controlled so that the molar ratio is 1.1 or more. Here, a preferable molar ratio is 1.15 or more, and a more preferable molar ratio is 1.2 or more.
  • the amount of the iron oxide powder and the amount of the reducing agent powder in the layer-filled portion are further included in the iron oxide powder.
  • the amount of carbon contained in the reducing agent powder with respect to the amount of oxygen contained is controlled to be 0.5 or more in a molar ratio.
  • the “layer-filled portion” refers to a cylindrical region formed by a layer of spirally deposited iron oxide powder and reducing agent powder. This corresponds to the portion excluding each of the aforementioned “layers made of reducing agent powder”.
  • the second invention is a method for producing reduced iron powder, in which the sponge iron produced according to the first invention is pulverized, reduced (finish reduction), and then further pulverized.
  • a third aspect of the present invention is a sponge iron sintered into a helix-like mass, preferably a high-purity sponge iron having a metal iron content of 97 mass% or more.
  • high-purity sponge iron can be produced even in a lump having a weight of 100 kg or more by, for example, applying a suitable condition (7) or the like and performing a reduction treatment for a sufficient time.
  • a fourth aspect of the present invention is a filling device that fills a container with iron oxide powder and reducing agent powder, the insertion portion being inserted into the container, and capable of rotating and moving up and down in the container;
  • Department An apparatus for filling sponge iron raw materials comprising an iron oxide powder discharge port and a reducing agent powder discharge port rotatably provided with the insertion section at a lower end of the sponge iron.
  • the iron oxide powder and the reducing agent powder are alternately and spirally formed in a reaction vessel. It is suitable for use in filling for deposition.
  • the opening areas of the iron oxide powder outlet and the reducing agent powder outlet are variable. Such a configuration can be suitably used in the first aspect of the present invention, particularly in order to satisfy the preferable condition (6).
  • the insertion part may be a cylindrical main body having a diameter of 85% or less of the inner diameter of the container, and a circle having a diameter of 90 to 95% of the inner diameter of the container.
  • a lower end portion formed of a part of a cylinder having a cross-sectional shape, and the horizontal cross-sectional shape of the lower ⁇ portion is a sector shape including the center of the circle and a part of the circumference, or a shape including the sector shape. It is preferable that there is.
  • Such a configuration is suitable for the purpose of reducing the thickness of the reducing agent powder layer in the outer peripheral portion described in the preferred condition (1) in the first present invention.
  • the insertion section can be inserted into the reaction vessel without interfering with the projection.
  • FIG. 1 is a cross-sectional view for explaining a conventional filling method of iron oxide powder and reducing agent powder.
  • FIG. 1B is a horizontal sectional view showing a section taken along the line IB-IB of FIG. 1A.
  • FIG. 2 is a perspective view showing the appearance of sponge iron obtained by a conventional method.
  • FIG. 3A is a cross-sectional view illustrating an example of a filling method of the iron oxide powder and the reducing agent powder according to the present invention.
  • FIG. 3B is a horizontal cross-sectional view showing a ⁇ —: ⁇ ′ cross section of FIG. 3A.
  • FIG. 4 is a schematic diagram showing an example of the structure of the insertion portion (rotary charging cylinder) of the present invention.
  • FIG. 4B is a cross-sectional view showing a filling state when the rotary charging cylinder of FIG. 4A is used.
  • FIG. 5 is a schematic diagram showing another example of the structure of the insertion portion (rotary charging cylinder) of the present invention.
  • FIG. 6 is a cross-sectional view illustrating another example of the filling method of the iron oxide powder and the reducing agent powder according to the present invention.
  • FIG. 7 is a perspective view showing the external shape of sponge iron obtained by the present invention.
  • FIG. 8 is a cross-sectional view illustrating an experimental example of a filling method in which iron oxide powder and reducing agent powder are horizontally deposited in multiple layers.
  • Figure 9 shows the relationship between the carbon content / oxygen content (molar ratio) (horizontal axis) and the required reduction time (vertical axis) in the alternate filling method for several different iron oxide layer thicknesses.
  • FIG. 10 is a cross-sectional view illustrating another experimental example of a filling method in which iron oxide powder and reducing agent powder are horizontally deposited in multiple layers.
  • Figure 11 shows the relationship between the amount of carbon in the alternating filling section, the amount of oxygen (molar ratio) (horizontal axis), and the required reduction time (vertical axis) in another alternating filling method. It is a figure which shows about thickness.
  • Figure 12 shows the relationship between the amount of carbon / oxygen (mol ratio) (horizontal axis) and the required reduction time (vertical axis) in the whole reaction vessel in different alternate deposition methods. It is a figure showing about iron layer thickness.
  • Figure 1 3 is, in spiral alternately filling (hatching) and a cylindrical packing (open), amount increase iron oxide (wt%, abscissa) metallic iron purity obtained by the reduction (mas S%, ordinate) of It is a figure showing a relation.
  • FIG. 14A is a sectional view showing still another example of the structure of the insertion portion (rotary charging cylinder) of the present invention.
  • FIG. 14B is an arrow view showing a section taken along the line XIVB—XIVB ′ of FIG. 14A (the thickness of the wall is omitted).
  • the meaning of each code is as follows.
  • reaction vessel sagar
  • Cut-out part 15 Iron oxide powder outlet
  • the present invention is characterized by a method for charging a raw material into a reaction vessel.
  • the raw materials are iron oxide powder and reducing agent powder, but if necessary, limestone or the like may be added together with the reducing agent.
  • FIG. 1 a method as shown in FIG. 1 is used.
  • a vertical cylindrical refractory reactor 1 is filled with an iron oxide powder 2 and a reducing agent powder 3 in a concentric cylindrical shape along the axial direction.
  • the method is adopted.
  • the present invention alternately fills the iron oxide powder and the reducing agent powder alternately and spirally with each other, that is, the structure in which both the containers are deposited is a spiral of iron oxide powder.
  • the method is to employ a method in which the layers and the spiral layers of the reducing agent powder are filled alternately in a stacked state (hereinafter referred to as “helical alternating filling”).
  • the filling with the iron oxide powder and the reducing agent powder can be performed simultaneously in parallel and continuously. For this reason, the thickness (filling amount) of each layer can be made constant. Therefore, the thickness ratio between the reducing agent layer and the iron oxide layer can be kept constant. This layer thickness ratio can be set to an arbitrary ratio for each reaction vessel depending on the purpose and situation.
  • the layer thickness ratio can be changed arbitrarily and at any time during charging.
  • the spiral alternating filling method is useful as a method that can greatly contribute to the improvement of production and production and the production volume.
  • 3A and 3B show an example of the present invention.
  • the raw material is charged by using a raw material charging device 14 in a cylindrical reaction vessel 11 (sagar) made of a refractory material such as SiC and the like. It is preferred to charge and fill 3 simultaneously.
  • the preferred configuration of the raw material charging device 14 is as follows.
  • the raw material charging device 14 is mainly composed of a rotary charging cylinder 14 b (charging portion) inserted into the reaction vessel 11.
  • the axial direction of the cylindrical body of the rotary charging cylinder 14 b is divided into two by the partition wall 14 a, and the chambers are partitioned, that is, the iron oxide powder storage section 17 and the reducing agent powder storage section 18 Can be charged with iron oxide powder 12 and reducing agent powder 13 (the powder in each storage section is not shown).
  • an iron oxide powder discharge port 15 and a reducing agent powder discharge port 16 are provided, respectively, to accommodate the storage sections 17 and 1 respectively. 8 are provided as openings.
  • each discharge port can be adjusted in opening degree (for example, opening height a), that is, opening area by a gate such as a slide gate.
  • the position and orientation of the discharge port may be determined as necessary.
  • Any surface of the cutout provided on the bottom, side, or bottom of the rotary charging cylinder 14b should be an opening. Can be.
  • each raw material powder is discharged by its own weight of the raw material powder charged in the storage section.
  • FIG. 4A shows an example of a detailed view of the rotary charging cylinder 14b.
  • a rectangular tubular cutout portion 14c protruding in a direction perpendicular to the partition wall 14a is provided at the extending position of the lower end portion of the tube.
  • FIG. 4B is a cross-sectional view of the filling process using such a rotary charging cylinder.
  • the cut-out portion for the iron oxide powder and the cut-out portion for the reducing agent powder can be arranged diagonally with respect to each other as a substantially quarter-circle sector. Conceivable. In this case, at least a part of the two outlets 15 and 16 should be provided on the side corresponding to the fan-shaped straight portion and on the same plane with the axis of the rotary charging cylinder 14b interposed therebetween. (The state is the cross-sectional view of FIG. 3A).
  • FIG. 5 is a detailed view showing another example of the rotary charging cylinder 14b.
  • the diameter of the rotary charging cylinder 14 b (especially at the lower end) be a value close to the inner diameter of the reaction vessel 11.
  • the reaction vessel is used repeatedly and a plurality of cylindrical units are stacked to form a reaction vessel, reduced iron and ash in the reducing agent adhere to the inside of the reaction vessel and become convex. A part may be formed.
  • the container may be slightly tilted due to the distortion caused by repeated use. Therefore, if the lower end of the rotary charging cylinder 14 b is almost the inner diameter of the reaction vessel 11, it may come into contact with the reaction vessel 11 when charging the rotary charging cylinder 14 b, which may cause damage. There is.
  • the purpose of making the diameter of the lower end of the rotary charging cylinder 14 b closer to the inner diameter of the reaction vessel 11 is to secure an opening from near the center of the reaction vessel to near the circumference for each outlet. It is. Therefore, if the position of the discharge port is devised, the horizontal cross-sectional shape of the lower end of the rotary charging cylinder 14b does not need to be a perfect circle, but a sector that forms a part of this circle (virtual circle), or Is sufficient if it has a shape including at least the sector.
  • FIG. 5 shows an example in which the lower end has a fan shape, and the iron oxide powder outlet 15 and the reducing agent powder outlet 16 are provided asymmetrically.
  • the outlet 15 for the iron oxide powder and the outlet 16 for the reducing agent powder are provided on the side surface (equivalent to the side of the sector) of the cutout portion 14c provided in the same manner as in FIG. I have.
  • the bottom surface of the cutout portion 14c is also open, the powders 12 and 13 are mainly discharged from the side surface because the deposited powder serves as a bottom surface.
  • 19 a and 19 b are holding plates.
  • the center angle of the sector may be arbitrary, but should be about 180 ° (ie, a semicircle) or less. This is preferable for making the lower end sufficiently compact. More preferably, the maximum crossover of the horizontal cross-sectional shape of the cutout portion is smaller than the diameter of the virtual circle.
  • the diameter of the virtual circle at the lower end is preferably closer to the inner diameter of the reaction vessel from the viewpoint of productivity, and is preferably about 90% or more of the inner diameter of the reaction vessel.
  • the diameter of the virtual circle is appropriately reduced, and it is preferable that the diameter is not more than about 95% of the inner diameter of the reaction vessel.
  • the diameter of the main body of the rotary insertion tube 14b is preferably about 85% or less of the inner diameter of the reaction vessel, and it is preferable to secure room for horizontal movement in the container in order to avoid contact.
  • the diameter of the main body is preferably about 30% or more of the inner diameter of the reaction vessel.
  • FIG. 6 shows another example of the filling method according to the present invention.
  • the raw material charging device 14 is shown in a simplified manner.
  • the position of the spiral alternate filling when filling the raw material powder into the reaction vessel, the position of the spiral alternate filling may be limited to a region excluding the outer peripheral portion along the axial direction of the cylindrical reaction vessel 11. . Further, the position where the spiral alternate filling is performed may be a region excluding the axial portion along the axial direction of the reaction vessel 11. Further, the position where the spiral alternate filling is performed may be a region excluding both the axial center portion and the outer peripheral portion along the axial direction of the reaction vessel. In any case, the region where the spiral alternate filling is performed is referred to as a cylindrical intermediate portion. The outer peripheral part and the axial center part correspond to the peripheral part and the central part, respectively, in the plan sectional view of the container.
  • the reducing agent layer in the outer peripheral portion is used to prevent interference between the rotary charging portion 14 b of the raw material charging device 14 and the reaction vessel 11, and to prevent seizure at the contact portion between the reaction container and the iron oxide powder. In some cases, it is unavoidable from the viewpoint of setting.
  • the reducing agent layer at the shaft center may be set for convenience in handling sponge iron from the container. As a result, a layer of only the reducing agent is present at the outer peripheral portion or at the axial center portion, thereby forming a passage for the reaction gas, thereby making the gas diffusion in the reaction vessel smooth and uniform. The effect of increasing the reduction reaction rate can also be expected.
  • the outer peripheral portion is formed of a reducing agent layer, it is possible to prevent the product from being welded to the vessel wall. Therefore, if necessary, it is preferable to provide these reducing agent layers while optimizing the layer thickness (radial direction) in consideration of the yield of the reducing agent and the amount of carbon / oxygen (molar ratio).
  • the outer periphery is about 2.5% or more and about 5% or less of the inner diameter of the vessel (diameter of the inner surface). It is preferable that the thickness be in the range (radial direction). On the other hand, the diameter of the shaft center is preferably about 250 or less.
  • an opening may be provided on the side of the rotary charging cylinder 14a, and the reducing agent powder forming the outer peripheral portion may be discharged from the opening.
  • a central cylindrical portion is further formed at a position where the partition wall 14c is provided in FIG. 4 and the like, and an opening is provided at a lower end of the central cylindrical portion.
  • openings may be connected to the outlet 16 for forming the spiral layer or may be independent.
  • FIG. 14A shows an example of the rotary charging cylinder capable of filling shown in FIG. Fig. 14B is a cross-sectional view at the XIVB-XIVB 'position in Fig. 14A (wall thickness is omitted for simplicity).
  • a reducing agent powder outlet 16 is provided on the bottom surface of the rotary charging cylinder 14b for alternate filling such as spiral alternate filling.
  • an opening is provided on the lower side surface of the rotary charging cylinder 14b to form a reducing agent powder outlet 16a for the outer peripheral part.
  • a reducing agent powder outlet 16b for the shaft center is provided on the bottom surface of the rotating loading cylinder 14b at the shaft center position, and a part of the reducing agent powder is guided by the partition wall 14d. It has become.
  • the bottom layer usually forms only a layer of reducing agent powder (and limestone), ensuring the reduction of the bottom iron oxide layer, and the reaction vessel and iron oxide layer. It is preferable to prevent seizure.
  • It can be formed by means such as stopping.
  • Such changes in the layer thickness include, for example, the rotation speed, the rising speed, It can be realized by adjusting any two or more of the opening degrees of the outlets 15 and 16.
  • the opening degree of the outlets 15 and 16 is controlled through gate opening / closing control, stable operation can be ensured without inducing gas diffusion resistance, prolonging the reduction time, and reducing production volume. It is preferable because it can be realized.
  • the layer thickness continuously or intermittently in the height direction of the vertical reaction vessel 11, for example, at the bottom, middle, or near the top. It does not preclude a variety of applications.
  • an application form in which the thickness of the iron oxide layer is increased in an upper part where the progress of reduction tends to be fast may be considered.
  • the thickness of the oxide layer and the reducing agent layer deposited spirally is preferably about 5 mm or more in each layer, and the sum of the two layers is preferably about 10 mm or more. More preferably, it is 40 or more thighs. If the layer thickness is excessively small, an unsteady portion tends to occur due to the fluctuation of the layer thickness.
  • a more preferred lower limit is about 10 mm or more for each layer, and about 30 mm or more for each layer.
  • the thickness of each layer is about 100 mm or less, and the sum of each layer is about 200 thigh or less.
  • a more preferable upper limit is about 80 mm or less for each layer, and about 150 or less for each layer.
  • the layer thickness ratio between the iron oxide layer and the reducing agent layer is generally not represented by the thickness but by the amount of carbon and the amount of oxygen (molar ratio). Suitable ratios will be described later.
  • the above-described raw material charging apparatus is an example.
  • the raw material charging apparatus has an insertion part that can be vertically moved and rotated. Is provided so as to rotate with the rotation of the inlet portion, and is inserted into the reaction vessel and raised while rotating the inlet portion, so that the iron oxide powder has a double helix from the outlet. Any structure may be used as long as it can deposit and fill the reducing agent powder.
  • the insertion portion is advantageously cylindrical, but is not limited to this.
  • a cylindrical body having a sectional shape such as a fan shape, a star shape, or a chrysanthemum shape depending on the shape of the reaction vessel may be used.
  • the storage section does not need to be formed of a partition plate, and its shape and position are arbitrary. It is not necessary that the iron oxide powder container and the reducing agent powder container have the same volume.
  • a fixed or movable guide plate, a holding plate, or the like is preferably provided around the discharge ports 15 and 16 in order to guide the raw material powder to be filled from the discharge ports in a target direction.
  • the iron oxide powder may be iron ore or steel. It is preferable to use, as a powder, iron oxide such as a mill scale generated in the hot rolling step. Also, in the so-called pickling process of removing oxides and the like on the surface of steel with an acid such as hydrochloric acid, waste acid (pickling waste liquid) is generated, and the pickling waste liquid is obtained by roasting or the like. Iron oxide powder is also preferred as the iron oxide powder. The preferred average particle size of these iron oxide powders is about 0.05 mm to about 10 cm.
  • finer iron oxide powder such as hematite powder having a specific surface area of 2 m 2 / g or more and a grain size of 0.01 ⁇ m or more industrially controlled, may be used in the above mill scale or iron ore. It is preferable to use the powder mixed with such a powder as it improves the quality of sponge iron.
  • a so-called carbonaceous powder containing carbon is used as the reducing agent powder.
  • the carbonaceous powder coatus powder, charcoal (a kind of volatile coal), coal powder (preferably non-coking), anthracite powder, charcoal powder and the like are suitable. From the viewpoint of reduction efficiency, the amount of carbon in the carbonaceous powder is preferably 60% or more.
  • a suitable average particle size with the reducing agent powder is also about 0.05 ⁇ to about 10 bandages.
  • the iron oxide powder 12 and the reducing agent powder 13 are placed in the reaction vessel 11 in the raw material charging apparatus 14 shown in FIGS. Fill alternately with a spiral.
  • the reaction vessel 11 for example, it is preferable to use a cylindrical reaction vessel made of SiC called sagar.
  • the shape of the reaction vessel 11 is not limited, but a cylindrical shape seems to be the most advantageous. Although there is no particular limitation on the dimensions of the reaction vessel, in the case of a cylindrical shape, the inner surface has a cross-sectional diameter of about 200 mm to about 800 mm and a height of about 100 mm to about 2000 strokes. It is suitable.
  • the reaction vessel 11 filled with iron oxide powder 12, reducing agent powder 13, and limestone or the like used as required is then loaded in a baking furnace such as a tunnel furnace while being loaded on a bogie or the like.
  • the raw material filled in the container is heated together with the container for a predetermined time for reduction.
  • This reduction is called crude reduction, and the target purity (the content of metallic iron in the reduced sponge iron) depends on the use of the reduced iron powder, but a high purity of at least about 90% mass S is required. It is about 97 mass% or more for the intended use. There is no upper limit to the purity target, but the purity that can be achieved at an acceptable cost is currently about 99.5 maSS % at maximum.
  • the preferred lower limit of the heating temperature is about 1000.
  • the preferred upper limit of the heating temperature is 1300 ° C. The preferred heating temperature is therefore in the range of 1000-1300 ° C.
  • the reaction vessel 11 When a tunnel furnace is used as a firing furnace, the reaction vessel 11 (and the iron oxide inside), which is placed on a carriage and moves inside the firing furnace, first moves through a pre-tropical region where the temperature gradually increases for 24 hours. (Preferably 20 hours or more, 28 hours or less), and a firing zone at about 1000 ° C to about 1300 for about 60 hours (preferably 36 hours or more, more preferably 56 hours or more) , And preferably 72 hours or less, more preferably 64 hours or less. Thereafter, the reduction treatment is completed through a cooling zone region in which the temperature gradually decreases (preferably, passing through 20 to 28 hours).
  • a pre-tropical region where the temperature gradually increases for 24 hours. (Preferably 20 hours or more, 28 hours or less), and a firing zone at about 1000 ° C to about 1300 for about 60 hours (preferably 36 hours or more, more preferably 56 hours or more) , And preferably 72 hours or less, more preferably 64 hours or less.
  • the reduction treatment is completed through a cooling zone
  • the inlet temperature in the pre-tropical zone and the outlet temperature in the cooling zone are about 200 ° C (about 20 ° C to about 400 ° C) .
  • the outlet temperature in the pre-tropical zone and the inlet temperature in the cooling zone are Approximately 900 ° C (firing zone temperature-450 ° C-firing zone temperature-about 50 ° C) Force It is preferable from the viewpoint of protection of the reaction vessel (refractory).
  • FIG. 7 shows an example of the external shape of sponge iron obtained by the method of the present invention (the upper and lower ends are omitted).
  • the height (axial direction) of the sponge iron ingot obtained is large, but there is no restriction on the size of the reaction vessel or the decrease in thermal efficiency due to the large firing furnace when the height of the reaction vessel is increased.
  • the size is preferably about 2000 mm or less.
  • high-purity sponge iron having a purity of 97 mass% or more can be obtained.
  • the purity is 97 ma SS % or more, it is advantageous in guaranteeing the product characteristics of sintered parts such as mechanical parts and magnetic materials, or reduced iron powder used as powder.
  • the method of the present invention has advantages other than purity, the purity is not limited to a method for producing high-purity sponge iron of 97 mass% or more.
  • the sponge iron produced is separated from the reaction vessel 11 and removed from the reducing agent.
  • the sponge iron taken out of the reaction vessel 11 is then coarsely pulverized, usually to about 150 ni or less, for further reduction, thereby obtaining coarse reduced particles.
  • the coarsely reduced particles are charged into a finishing reduction furnace in a reducing atmosphere and subjected to finish reduction, and are further pulverized into reduced iron powder.
  • the ratio of the amount of iron oxide and the amount of reducing agent (solid reducing agent) when performing the above-mentioned spiral alternating filling, particularly the amount of oxygen in the iron oxide is required.
  • the ratio of the amount of carbon in the reducing agent has already been described together with the formula (2).
  • carbon content / oxygen content (molar ratio) 1. 0.
  • a larger amount of carbon than the amount of oxygen in iron oxide is required as a reducing agent.
  • the reduction ratio target purity of sponge iron
  • the reduction ratio is 90 mass% or more for metallic iron, and preferably 97 mass% or more.
  • the present inventors investigated the relationship between the carbon amount / oxygen amount (molar ratio) and the required reduction time in the spiral alternating filling method of the present invention by the following experiment.
  • the inner diameter of the reaction vessel used for the experiment was 370, and the filling height was 1400 mm.
  • the same iron oxide powder and reducing agent powder as those used in Example 1 described later were used.
  • the reduction treatment was performed at a maximum temperature of 1150 ° C.
  • the reduction time refers to the holding time at this maximum temperature.
  • Figure 9 shows how to obtain carbon content (molar ratio) and oxygen content in iron oxide in a plurality of horizontal alternating filling systems with different iron oxide layer thicknesses and to obtain 97 mass% iron (metallic iron) sponge iron. It is a graph which shows the relationship with the required reduction time.
  • the molar ratio is the ratio between the total iron oxide and the total reducing agent in the container.
  • FIG. 9 an example of the result of performing the same reduction treatment using the conventional cylindrical filling method (FIG. 1) is indicated by a circle (conventional example: Association).
  • this conventional method the thickness of the iron oxide layer was set to 55 and the amount of carbon / oxygen (molar ratio) was set to 2.2, but the reduction time was as long as 53 hours.
  • the thickness of the iron oxide layer was 15 (Experimental example 4: X mark), 20 (Experimental example 3: triangle mark), 30 mm (Experimental example 2: square mark (, Reduction experiments were performed for each case of 50 mm (Experimental example 1: rhombus mark ( ⁇ )).
  • the reduction time was shortened by reducing the thickness of the iron oxide layer. It was found that when the molar ratio was 1.2 or more, the reduction time became almost constant, and it was not necessary to secure a molar ratio of 2.0 or more as in the conventional case.
  • the spiral method can fill more iron oxide, for example, in this example, the spiral alternate filling method with an iron oxide layer thickness of 30 oz. Is filled with almost the same amount of iron oxide as the conventional cylindrical filling method. Have been. Therefore, the effects of the present application are sufficiently obtained in the experimental range of the molar ratio of 1.1 or more. In addition, if the molar ratio is 1.15 or more, the degree of prolongation of the reduction time is relatively small. Then, it is roughly effective.
  • the thickness of the iron oxide layer was 15 mm, the reduction time was almost constant at a molar ratio of 1.6 or more. The experiment was repeated under different conditions. As a result, it was found that the following relationship was satisfied when the thickness of iron oxide was less than 20 corruption.
  • the filling is performed so as to satisfy the above formula (3) . If the thickness of the oxidized iron layer is determined, the reduction time is determined and the operation is stabilized. However, the quality of sponge iron obtained is also stable. However, this relationship may be due to the fact that the thickness of the reducing agent layer becomes thinner, making it difficult to control the layer thickness stably, rather than to the essential relationship based on the reaction rate. It is expected that the above restrictions will be relaxed with the improvement.
  • the reducing agent layer is provided on the outer peripheral portion or the axial center portion of the container, only the amount of carbon and the amount of oxygen (molar ratio) in the entire container are regulated, and the reducing agent layer is added. The present inventors thought that it was necessary to investigate whether or not the thickness ratio with the iron oxide layer was sufficient as a guide for designing.
  • the inventors of the present invention set the required amount of the reducing agent in the portion of the raw material deposition layer (cylindrical intermediate portion) in the reaction vessel as a ratio of the thickness of the iron oxide and the reducing agent to some tendency in the reduction behavior.
  • the molar ratio of the amount of carbon in the reducing agent to the amount of oxygen in the iron oxide charged in the reaction vessel was kept constant at 1.2, and the vicinity of the wall (outer periphery) and the center of the axis of the reaction vessel were An experiment was conducted in which the amount of carbon in the reducing agent was changed with respect to the amount of oxygen in the iron oxide in the portion where the reducing agent was removed, that is, the portion where both were deposited in layers.
  • Fig. 10 shows a schematic cross-sectional view of the filling method used in the experiment.
  • the reduction layer covering the upper and lower surfaces of the cylindrical intermediate portion also It shall be included in the intervening part.
  • the raw materials and experimental conditions were the same as in the previous experiment.
  • FIG. 11 shows the change in the reduction time with respect to the carbon content and the oxygen content (molar ratio) at several different iron oxide layer thicknesses.
  • the circles (hata) in the figure are the values when the laminating method shown in Fig. 8 is used without providing the reducing agent layer on the outer periphery and the axial center.
  • the thickness of the iron oxide layer was 60 mm (Experimental example 11: diamond-shaped mark (decree)), 50 mm (Experimental example 12: Square mark (solid)), 30 mm (Experimental example)
  • the reduction was carried out at four levels of 13: triangle mark and 20 mm (Example 14: X mark).
  • 13 triangle mark and 20 mm (Example 14: X mark).
  • the reduction time is shortened by reducing the thickness of the oxidized iron layer, and the reduction time becomes almost constant when the amount of carbon / oxygen (molar ratio) becomes 0.5 or more. It was found that the reduction time was prolonged when the ratio was less than 0.5.
  • the cylindrical intermediate portion which is the portion of the spirally packed layer (alternately filled portion), is required. It was found that it is preferable to set the amount of carbon and the amount of oxygen (molar ratio) to 0.5 or more.
  • the molar ratio of the amount of carbon in the reducing agent to the amount of oxygen in the iron oxide in the cylindrical intermediate portion was kept constant at 0.8, and the reduction to be filled in the axial center portion and the outer peripheral portion of the reaction vessel was performed.
  • An experiment was performed in which the amount of the agent was changed. The results of the experiment are shown in Fig. 12 as a graph of the change in reduction time with respect to the total amount of carbon Z and the total amount of oxygen (molar ratio) in the entire reaction vessel. The symbols used correspond to the same plate thickness as in FIG.
  • the effect of the present invention can be sufficiently obtained with less than 1.2 and more than 1.1, preferably more than 1.15.
  • these raw materials are put into the reaction vessel 11.
  • the charging ratio of the iron oxide and the reducing agent as a whole in the reaction vessel 11 including the axial center portion, the outer peripheral portion, and the cylindrical intermediate portion is the total amount of the reducing agent with respect to the oxygen amount in the iron oxide.
  • the molar ratio of the amount of carbon is preferably 1.1 or more, more preferably 1.15 or more, and even more preferably 1.2 or more.
  • the thickness ratio between the iron oxide and the reducing agent in the cylindrical intermediate portion in which the raw material was filled into a spiral layer is shown by the molar ratio of the amount of carbon in the reducing agent to the amount of oxygen in the iron oxide. In this case, it is preferable that the value be 0.5 or more.
  • each experimental level as shown in Table 1 was set, and an oxide layer and a reducing agent layer were filled in a reaction vessel 11 made of SiC by a method conforming to each of the above levels, and a crude reduction treatment was performed. Then, sponge iron was manufactured. That is, levels A to C and H in the table are examples of the cylindrical filling method shown in FIG. 1, levels D to F are examples of the spiral alternating filling method shown in FIG. 6, and level G is an example of the horizontal alternating filling method.
  • the 20% increase in the filling amount for levels A and D means that the total thickness of the mill scale in the reaction vessel 11 increases by 20%
  • the 40% increase in the filling amount for levels B and E Means that the total thickness of the mill scale in the reaction vessel 11 is increased by 40% in total
  • the 60% improvement in the filling amount of the levels C and F means that the mill scale in the reaction vessel 11 is This means that the total layer thickness increases by a total of 60%.
  • Table 2 shows the details of each condition. Under these conditions, each level filled was examined and the filling method, suitable layer thickness and purity were determined. In this experiment, the iron oxide, the main raw material, was prepared by drying the mill scale generated in the hot rolling process, pulverizing it, and sieving it.
  • the obtained mill scale powder was used (the average particle size was confirmed to be between 0.05 mm and 10 mm).
  • a mixture of limestone powder and carbonaceous powder was used as a reducing agent as an auxiliary material.
  • the carbonaceous powder used was an anthracite with a ratio of about 7: 3, and the average particle size of coke was 85 m and the average particle size of anthracite was 2.4 mm.
  • the limestone powder added limestone powder having an average particle size of 80 ⁇ to the reducing agent powder by about 14 mass%.
  • the reaction vessel is a cylindrical vessel with an inner diameter of 400.
  • the iron oxide layer has an outer diameter of 320 thighs, the thickness shown in Table 2 and the height (axial direction) of about 1500 mm. Filled so that In the case of spiral filling, a reducing agent layer with a diameter of about 80 mm at the center of the shaft and a thickness of about 15 at the outer periphery is formed. Direction) about 1500 As a packed layer.
  • the carbon content / oxygen content (molar ratio) in the container and in the cylindrical intermediate portion were 1.2 or more and 0.5 or more, respectively. table 1
  • the horizontal alternating filling was performed for the purpose of confirming the filling efficiency. That is, using the same raw material charging apparatus as that used for the helical alternating charging, the rotary charging cylinder is swirled while charging only one of the iron oxide powder and the reducing agent powder, and the rotary charging is performed. After the cylinder was raised, the procedure of filling the other powder in the same manner was repeated. As shown in Table 1, continuous filling is not possible in horizontal alternating filling, and the filling time is longer than in cylindrical filling and spiral alternating filling. In the case of spiral alternating filling, the filling time can be shortened most.
  • Each reaction vessel 11 filled with the raw materials based on each experimental level was loaded on the same bogie and charged into a tunnel furnace.
  • the loaded trolley passed through the pre-tropical zone (200 ° C to 900 ° C) in about 1 day and passed through the firing zone (at 1150) in about 3 days. After that, it passed through the cooling zone (200 ° C to 900 ° C) for about one day, the bogie was discharged from the tunnel furnace, and the sponge iron was taken out of the vessel and its purity was measured.
  • Each sponge iron weighed 200 kg or more.
  • the purity of sponge iron is determined by converting the metallic Fe content from the chemical components determined by oxygen analysis. I did.
  • Figure 13 shows the results. As shown in Fig. 13, in the case of spiral alternating filling (hatching), reduction is good and the purity is 97 mass% or 98 mass% when the iron oxide layer thickness is up to 60 ⁇ , that is, up to 40% in productivity improvement allowance. High-purity sponge iron has been obtained, indicating that productivity can be adjusted by layer thickness up to 40% increase compared to the conventional method.
  • the aim is to improve productivity by 20%, the layer thickness will reach 75 mm, and the purity will be 95.65 mass%, so it is impossible to improve productivity as much as spiral alternating packing.
  • Sponge iron was produced by the methods of Invention Examples 1 to 5 and Conventional Example 1 below.
  • the filling method was substantially that shown in Fig. 3A, and the carbon content / oxygen content (molar ratio) was 1.2 or more.
  • the reaction vessel was spirally and alternately filled at an equal thickness ratio where the layer thickness of iron oxide was 50 mm and the total thickness of the reducing agent was 50 mm.
  • the reaction vessel used was a cylindrical vessel with a height of 1.8 m and an inner diameter of 40 cm.
  • As the reducing agent powder a mixture of limestone of 16 mass% (average particle size of about 95 m) mixed with a coatus powder having a particle size of less than 1 bun was used.
  • the iron oxide powder used was a mill scale pulverized to less than 0.1 thigh (which was pulverized, sieved, and adjusted so that particles passing through 60 111 mesh became about 40 mass%).
  • the average particle size of both mill scale powder and coke powder is 0.05 mn!
  • the raw material charging device shown in Fig. 4A was used.
  • the opening height of the iron oxide powder outlet 15 was set to 50 mm, and the opening height of the reducing agent powder outlet 16 was set to 50 mm.
  • the rotating cylinder 14b was filled at a rotational speed of 4 revolutions per minute for 4 revolutions and a rising speed of 400 bpm.
  • the reaction vessel was spirally and alternately filled with an equal thickness ratio of iron oxide layer thickness of 35 mm and reducing agent layer thickness of 65 mm.
  • the opening height of the iron oxide powder outlet 15 is 35 hidden
  • the opening height of the reducing agent powder outlet 16 is adjusted to 65 thighs
  • the rotation speed of the rotary charging cylinder 14 b is set to 4
  • the rotation and the ascending speed were filled as 400 marauders Z minutes.
  • This example is an example in which the reaction container is spirally and alternately filled at an equal thickness ratio where the thickness of the iron oxide is 60 and the thickness of the reducing agent is 40.
  • the reaction vessel, raw material powder and raw material charging apparatus used were the same as in Invention Example 1, and were charged with iron oxyacid and a reducing agent.
  • the opening height of the iron oxide powder outlet 15 is set to 60 mm
  • the opening height of the reducing agent powder outlet 16 is adjusted to 40 mm
  • the rotation speed of the rotary charging cylinder 14 b is increased by 4 minutes.
  • the rotation and the ascending speed were filled at 400 o'clock.
  • the reaction vessel is spirally filled alternately at an equal thickness ratio with the layer thickness of iron oxide being 25 mm and the layer thickness of the reducing agent being 25 mm.
  • the used reaction vessel, raw material powder and raw material charging device were the same as in Invention Example 1, and were charged with iron oxide and a reducing agent. Adjust the opening height of the iron oxide powder outlet 15 to 25 mm, adjust the opening height of the reducing agent powder outlet 16 to 25 thighs, and adjust the rotation speed of the rotary charging cylinder 14 b to 4 The rotation and ascending speed were filled at 200 strokes Z.
  • This example shows an example in which the thickness of the iron oxide layer is 57.5 mm and the reducing agent is 50 mm in the reaction vessel.
  • the same reaction vessel, raw material powder and raw material charging apparatus as those of Invention Example 1 were used, and were charged with iron oxide and a reducing agent.
  • the opening height of the iron oxide powder outlet 15 is 57.5 mm
  • the rotating charging cylinder 14b with the opening height of the reducing agent powder outlet 16 adjusted to 50 thighs was filled at a rotation speed of 4 rotations per minute and a rising speed of 430 mm / min.
  • a cylindrical vessel was filled based on the conventional method shown in Fig. 1.
  • the same reaction vessel as in Example 1 was used, and iron oxide was formed into a cylindrical shape with a thickness of 57.5 mm and an outer diameter of 310 mm ⁇ .
  • a powder layer was formed, and the reducing agent powder was filled around the iron oxide layer (including the inside of the cylinder).
  • the same reaction vessel and raw material powder as those of Invention Example 1 were used.
  • the amount of carbon in the container and the amount of oxygen (molar ratio) were about 2.2.
  • the reduction treatment was performed using a tunnel furnace, and the time required for the reduction was examined.
  • the time required for reduction refers to a retention time in a calcination zone (1150 ° C) for obtaining sponge iron having a purity of 95% or more.
  • the productivity per hour is the value obtained by dividing the weight of iron oxide charged by the time required for reduction.
  • Invention example 1 Invention example 2 Invention example 3 Invention example 4 Invention example 5 Conventional example 1 Filling method Spiral alternating filling Cylindrical filling Iron oxide layer thickness
  • reducing agent powder 13 (coke powder) was deposited on the bottom of the reaction vessel 11 to a thickness of 30 strokes.
  • the rotating charging cylinder 14 b having the iron oxide powder discharge port 15 and the reducing agent powder discharge port 16 is rotated upwards while rotating, so that the iron oxide powder having a thickness of 40 mm is obtained.
  • 1 2 (mill case) and a reducing agent powder 13 having a thickness of ⁇ were alternately and continuously filled in a spiral manner in the reaction vessel.
  • the upper end of the reaction vessel 11 was filled with reducing agent powder (Cotas powder) 13. In this filling, the molar ratio of the amount of carbon in the reducing agent to the amount of oxygen in the oxidized iron was 1.6.
  • the other conditions were the same as in Example 2.
  • the filling schedule is as follows.
  • the reducing agent powder (coats powder) 3 is first filled into the bottom of the reaction vessel 11 to a thickness of 50 mm.
  • Iron oxide powder (mill scale) 12 was cut out to a thickness of 40 mm and deposited thereon, and was repeatedly filled up to the upper end of the reaction vessel 11 according to such a filling schedule.
  • the upper end of the reaction vessel 11 is filled with a reducing agent powder (copper powder) 13.
  • the molar ratio of the amount of carbon in the reducing agent to the amount of oxygen in the iron oxide was 1.6.
  • the bogie speed is 1.3 mZhr, 18% faster than the conventional example of 1. lm / hr.
  • the amount of mill scale filled was 220 kg 16% larger than the container, 256 kgZ container. As a result, productivity increased by 38%.
  • the amount of heat required for heating per unit mass of sponge iron was reduced by about 30% from 11470 MJ / ton to 8820 MJ / ton.
  • the sponge iron was manufactured using the raw material charging device shown in Fig. 5.
  • the raw materials used are the same as in Example 2.
  • the cutout 14c was semicircular (sector-shaped with a central angle of about 180 °).
  • the reaction vessel was 400 thigh in diameter and 2,000 mm in height, and the rotary charging cylinder was inserted without intentionally removing the convex part (maximum height of about 20 mm) due to the welded reaction product slag.
  • the outer shape of the rotating charging cylinder main body was 310 mm (77.5% of the inner diameter of the container), and the diameter of the imaginary circle in the plane cross section of the cutout was 360 mm (90% of the inner diameter of the container).
  • the tip of the rotary charging cylinder is slightly in contact with the convex part and the reaction vessel, it can be moved to the opposite side, so that it can be inserted without problems to the lowermost end of the reaction vessel, and there is no problem in inserting the raw material powder.
  • the anti-reaction container vessel, the iron oxide powder 260kg could filled without problems (layer of iron oxide thickness: 50 strokes, reducing agent layer thickness: 30 thigh) 0
  • the iron oxide powder used as the main raw material was mill scale or iron ore powder. Was appropriately pulverized. Further, as the reducing agent powder, at least one kind of a single substance or a mixture of a powder of coal, a powder of charcoal, a powder of charcoal and the like was used by appropriately pulverizing and adjusting the particle size. Each has an average particle size of about 70 ⁇ ! 9090 m.
  • the equipment has a rotating charging cylinder as shown in Fig. 14.At the start of operation, first, a reducing agent powder 13 is spread on the bottom of the reaction vessel 11 and iron oxide powder 12 is reduced on top of it. The agent powder 13 is charged alternately in a spiral layer at the same time while rotating the swirl charging cylinder 14 b of the raw material charging device 14, and is alternately charged into the spiral layer. I went up. Then, the top of the reaction vessel 11 was filled with a reducing agent powder 13 and covered. In order to prevent the removal of the product (sponge iron) and the adhesion of the sponge iron to the container, and to enhance the diffusion efficiency of the reaction gas, the outer periphery of the shaft center and the vicinity of the container wall is a reducing agent. Only filled.
  • a refractory reaction vessel 1 (inner diameter 400, length 1800 mm) contains an iron oxide layer with an outer diameter of 310 mm, an inner diameter of 200 mm, and a length of 1600 (the other parts are reducing agents) was charged.
  • the amount of carbon in the container and the amount of oxygen (molar ratio) were set to 2.2, and the reduction time (1150 ° C, the same applies hereinafter) with the target purity of 97.0 ma SS % was 53 hours.
  • the iron oxide has an outer diameter of 390 mm, an inner diameter of 60 mm, thickness 6 0 Yuzuru spiral, the other as a similar spiral in the reducing agent layer thickness 45 mm, Both were filled at the same time.
  • the molar ratio of the carbon content and the oxygen content of the iron oxide and the reducing agent in the cylindrical intermediate portion was 0.8, and the carbon content and the oxygen content (molar ratio) of all the filling materials were 1.2.
  • the filling amount was first increased by 35% compared to Conventional Example 3, but the reduction time was only 60 hours. The sponge iron did not adhere to the inner surface of the container and was easily removed.
  • a spiral spiral filling method is used.
  • the iron oxide is a spiral with an outer diameter of 365 mm, an inner diameter of 100 mm, and a layer thickness of 60 mm.
  • the reducing agent has a layer thickness of 28 mm. Both were filled at the same time.
  • the molar ratio of the carbon content and the oxygen content of the oxidizing iron and the reducing agent at the cylindrical intermediate portion was 0.5, and the molar ratio to the total filling was 1.2.
  • the filling amount increased by 35% compared to Conventional Example 3,
  • the payback time stopped at 59 hours.
  • the sponge iron did not adhere to the inner surface of the container and was easily removed.
  • the spiral alternating filling method is used.
  • the iron oxide is a spiral with an outer diameter of 350 mm, the inner diameter is 100 mm, and the layer thickness is 60 mm. Both were filled at the same time.
  • the sponge iron did not adhere to the inner surface of the container and was easily removed.
  • the reduction time was almost the same as in Conventional Method 3 even if the increase was considered.
  • iron oxide is a spiral with an outer diameter of 375 mm, an inner diameter of 100 mm, and a layer thickness of 60 mm. Both were charged at the same time.
  • the molar ratio of the carbon content of the iron oxide and the reducing agent and the oxygen content of the oxygen in the cylindrical intermediate part was 0.8, and the molar ratio to the total charge was 1.5.
  • the filling amount increased by 20% compared to Conventional Example 3 and stopped at a reduction time of 59 hours.
  • the sponge iron did not adhere to the inner surface of the container and was easily removed.
  • Inventive Example 7 in which the amount of carbon / oxygen (molar ratio) in the container is relatively low, has a higher production efficiency per reduction time, but also in this example, better results are obtained than in the prior art.
  • a spiral spiral filling method is used.
  • the iron oxide is a spiral with an outer diameter of 395 mm, an inner diameter of 40 mm, and a layer thickness of 60 mm. Both were filled simultaneously as a spiral.
  • the molar ratio of carbon / oxygen in the middle part of the cylinder was 0.8, the molar ratio to the total charge was 1.1, and the charge was 40% higher than in Conventional Example 3, but the reduction time was 78 hours.
  • the sponge iron did not adhere to the inner surface of the container and was easily removed. In this example, the reduction time was slightly longer, and the reduction time was almost the same as in Conventional Method 3 even if the increased amount was considered. Table 5 summarizes the above results. Table 5
  • Iron oxide :: Amount (relative ratio) / Reduction time (h)
  • sponge iron can be manufactured while ensuring high productivity and quality (for example, purity of 97% or more) by employing the spiral alternating filling technique.
  • high productivity and quality for example, purity of 97% or more
  • the raw material filling structure in the reaction vessel can be changed arbitrarily, easily and quickly, it is easy to adjust the quality “quantity” reduction time and the like, and it is possible to realize a remarkable improvement in production efficiency. Consequently, high-purity sponge iron can be produced at low cost.

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Abstract

L'invention concerne un procédé servant à produire de l'éponge de fer et comprenant le chargement d'une poudre d'oxyde de fer et d'une poudre d'agent réducteur dans une cuve à réaction, ces poudres étant empilées en alternance en spirale, et la réduction de l'oxyde de fer. Dans ce procédé, l'efficacité de la réaction gazeuse est satisfaisante, et la qualité et la productivité sont élevées. Le procédé selon l'invention est également avantageux pour l'ajustement de la production, par exemple parce que les quantités de matériaux d'alimentation chargés peuvent être régulées sans limitation due au temps de réduction. L'invention concerne également un dispositif de charge pour la production. Le rapport de la quantité de carbone dans l'agent réducteur à la quantité d'oxygène dans l'oxyde de fer dans la cuve de réaction est, de préférence, égal à 1,1 ou plus par mole.
PCT/JP2004/000866 2003-01-31 2004-01-29 Procede pour produire de l'eponge de fer et de la poudre de fer reduite, eponge de fer et dispositif de charge Ceased WO2004067784A1 (fr)

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CN102794455A (zh) * 2012-09-05 2012-11-28 昆明理工大学 一种内外配炭相结合、微波加热制备一次还原铁粉的方法

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US20110018179A1 (en) 2009-06-29 2011-01-27 Bairong Li Metal reduction processes, metallurgical processes and products and apparatus
CN103146865B (zh) * 2013-03-29 2014-10-01 青岛理工大学 一种基于生物质热解焦油的直接还原炼铁装置和方法
CN103438703B (zh) * 2013-06-25 2017-01-18 吉林省华兴粉末冶金科技有限公司 原料铁粉装料装置
WO2017004239A1 (fr) 2015-06-29 2017-01-05 Loewen Joanne Chargeur de dispositif mobile
CN106623910B (zh) * 2016-11-25 2018-09-14 太原理工大学 一种微叠层粉体铺层装置
CN109663924A (zh) * 2017-10-14 2019-04-23 朝阳市金麟铁精粉有限公司 还原铁粉装筒装置

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