WO2007083450A1 - Process for producing metallic iron - Google Patents
Process for producing metallic iron Download PDFInfo
- Publication number
- WO2007083450A1 WO2007083450A1 PCT/JP2006/323928 JP2006323928W WO2007083450A1 WO 2007083450 A1 WO2007083450 A1 WO 2007083450A1 JP 2006323928 W JP2006323928 W JP 2006323928W WO 2007083450 A1 WO2007083450 A1 WO 2007083450A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- iron
- slag
- raw material
- molten slag
- iron oxide
- Prior art date
Links
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
- C21B13/0046—Making spongy iron or liquid steel, by direct processes making metallised agglomerates or iron oxide
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0066—Preliminary conditioning of the solid carbonaceous reductant
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/008—Use of special additives or fluxing agents
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/10—Making spongy iron or liquid steel, by direct processes in hearth-type furnaces
- C21B13/105—Rotary hearth-type furnaces
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen
Definitions
- the present invention relates to an improvement in technology for producing metallic iron by heating and reducing an iron source such as iron ore with a carbonaceous reducing agent such as Cortus, and more specifically, reducing iron oxide and carburizing.
- the present invention relates to a method for efficiently producing metallic iron having a predetermined carbon concentration by efficiently separating the produced metallic iron and the slag forming component mixed as raw material ore as a gangue component. .
- Patent Document 1 One of the inventors of the present invention previously proposed the method described in Patent Document 1 as a new type of direct iron manufacturing method, and will continue to improve the direct iron manufacturing method.
- metallic iron is produced by heating and reducing a raw material mixture containing a carbonaceous reducing agent and iron oxide, and iron oxide is reduced to a reducing gas derived from the carbonaceous reducing agent.
- the metal iron skin is generated and grown by reduction at a low temperature, and the reduction proceeds in a solid state until iron oxide is substantially absent inside the metal iron skin. It is characterized by the fact that it flows out of the outer skin and separates metallic iron and slag.
- the molten iron slag generated by heat reduction may be melted so that the molten slag inside the metallic iron shell flows out of the outer skin.
- the melting point of the metallic iron shell is obtained by dissolving carbon derived from the carbonaceous reducing agent present in the metallic iron shell in metallic iron (this phenomenon is sometimes called “carburizing”). Let ’s descend.
- Patent Document 2 iron dust is used as an acid pig iron source, and this is mixed with a carbonaceous reducing agent (hereinafter sometimes referred to as carbonaceous material) and an auxiliary material (slag forming agent),
- carbonaceous material hereinafter sometimes referred to as carbonaceous material
- auxiliary material slag forming agent
- a method of producing metallic iron by heat reduction and separating granular metallic iron from a low melting point slag containing FeO is disclosed.
- This method is a method in which iron-making dust is used as a source of iron oxide.
- the basicity adjustment of the slag-forming components adopted in this method is performed at the time of mixing the raw materials, so slag produced during heat reduction is sufficient research on the behavior of acid iron in the slag. It was made ⁇ ⁇ .
- Patent Document 3 the basicity of the slag forming component in the raw material is controlled in the range of 0.4 to 1.3, and 1Z3 or more of the time required for heat reduction on the hearth is 1200 to 1200
- the basic idea of the present invention is that when a raw material mixture containing a carbonaceous reducing agent and iron oxide is heated and reduced to produce metallic iron, the raw material mixture is produced during the reduction and melting of the raw material mixture and contains a gangue component.
- the liquid phase ratio in the solid-liquid coexisting phase of the component slag By controlling the liquid phase ratio in the solid-liquid coexisting phase of the component slag, the carburization and melting of the generated solid metallic iron is promoted. Specifically, the melting temperature of the metallic iron is controlled.
- it is characterized by controlling the carbon content (carbon concentration, the same shall apply hereinafter) of the obtained metallic iron.
- the operation is as follows. That is, the relationship between the composition and temperature of the slag forming component contained in the raw material mixture and the liquid phase ratio is determined in advance, the amount of ash in the raw iron oxide component and the carbonaceous reducing agent is adjusted, and the amount of mixture into the molten slag is adjusted. It is also necessary to adjust the amount of slag forming component added if necessary. Therefore, further development of this method is desired, and the development of a method capable of efficiently producing metallic iron having the target carbon concentration by simpler operation is desired.
- This non-patent document 1 relates to the reduction of acid pig iron in the blast furnace and the carburizing behavior of the produced reduced iron (metallic iron), and the acid pig iron as shown in the conceptual diagram of FIG. (FeO) is reduced in the molten slag (S) by a carbonaceous material (G: graphite), and the behavior of the produced metallic iron (Fe) when carburized is clarified.
- iron oxide (FeO) in molten slag (S) is reduced and carburized by carbon (C) derived from a carbonaceous reducing agent (ie, carbonaceous material, G), and carburized molten iron (Fe— C) is generated.
- the FeO concentration in the slag in contact with the charcoal decreases, resulting in a difference in concentration from the FeO concentration in the slag in contact with the reduced iron.
- the carburized molten iron (Fe—C) tries to move away from the charcoal force, moves quickly in the direction of the solid reduced iron (S—Fe), and adheres to the solid reduced iron (S—Fe).
- the solid reduced iron is carburized.
- Patent Document 1 Japanese Patent Laid-Open No. 9-256017
- Patent Document 2 Japanese Patent Laid-Open No. 10-147806
- Patent Document 3 Japanese Unexamined Patent Publication No. 2000-45008
- Patent Document 4 Japanese Patent Laid-Open No. 2005-48197
- Non-Patent Document 1 ISU International, Vol. 44 (2004), No. 12, pp. 2033--2039 Disclosure of Invention
- the present invention has been made in view of the above situation, and the features developed by the present inventors.
- the purpose is to provide an iron manufacturing method that further improves operability and efficiency compared to the direct iron manufacturing method disclosed in Permitted Document 4.
- the present invention is a method for producing metallic iron from a raw material mixture containing a carbonaceous reducing agent and an iron oxide-containing substance, wherein the above-mentioned predetermined carbon concentration in metallic iron is determined according to Determining the target production temperature of the initial molten slag that is initially produced in the raw material mixture by heating the raw material mixture, including the gangue component, unreduced iron oxide, and ash in the carbonaceous reducing agent A step of preparing the raw material mixture for generating the composition of the initial molten slag according to the target generation temperature, and heating the raw material mixture to reduce and melt the raw material mixture, and And a step for producing molten slag.
- FIG. 1 conceptually shows the movement of molten iron salt in molten slag in which carbon exists and one of the inventors of the present invention and the carbon carrier action of molten iron. It is the shown schematic diagram.
- Figure 2 shows the composition of CaO, SiO 2, Al 2 O 3 and FeO, which are the main components of molten slag.
- FIG. 1 A first figure.
- FIG. 3 is a graph showing an example of the relationship between the metallization rate during heat reduction and the remaining unreduced FeO.
- FIG. 4 is a graph showing the change of the reduction rate (in this specification, metalization rate and V) in relation to the heat reduction treatment time.
- FIG. 5 is a graph showing the effect of the content of iron oxide (FeO) in the slag on the initial molten slag formation temperature and the CO gas generation start temperature.
- FIG. 6 is a graph showing the effect of the content of iron oxide (FeO) in the slag on the initial molten slag formation temperature and the CO gas generation start temperature.
- FIG. 7 is a graph showing the relationship between the initial molten slag formation temperature and the carbon concentration in the molten metal iron (product metal iron) obtained at that temperature.
- an iron oxide-containing substance such as iron ore, iron oxide, or a partially reduced product thereof, and a carbonaceous reducing agent such as coatas and coal are used.
- a “target formation temperature of initial molten slag” is determined according to a predetermined target carbon concentration in metallic iron, Prepare a raw material mixture that generates the composition of the initial molten slag according to the target generation temperature, and further heat the raw material mixture to reduce and melt the raw material mixture and generate the initial molten slag.
- the initial molten slag is slag that is first generated in the raw material mixture, and contains a gangue component, unreduced iron oxide, and ash in the carbonaceous reducing agent.
- Patent Document 4 As a result of further research aimed at further improving the technique described in Patent Document 4, the present inventors have discovered the phenomenon disclosed in Non-Patent Document 1, that is, oxidation in molten slag in a blast furnace. We thought that the iron production technology of Patent Document 4 could be further improved by making good use of iron reduction and carburization behavior.
- molten slag that melts solid reduced iron at a lower temperature and by-produces it during the heating reduction process. It is important how to separate them efficiently (hereinafter referred to as by-product slag). For that purpose, how quickly the carburization of the solid reduced iron proceeds to melt the solid reduced iron (in this specification, the phenomenon that the solid reduced iron undergoes carburization and melts is referred to as "reduced iron melted down" Is important).
- Non-Patent Document 1 the molten reduced iron produced by carburizing and carburizing in the molten slag is obtained as described above. We thought that it could be used as a carrier for transporting carbon in the direction of solid metal iron when moving in the direction of solid metal iron due to the phenomenon, and further research was conducted along that line.
- Patent Document 4 the method previously developed by one of the present inventors is that the liquid phase ratio of by-product slag is closely related to the melting of metallic iron. At that time, based on new knowledge, control was introduced by introducing a new concept of the liquid phase ratio in the solid-liquid coexisting phase of by-product slag rather than melting all the by-product slag. To do.
- the solid metallic iron produced by the heat reduction can be carburized at a lower operating temperature, and the melting point thereof can be quickly lowered. And this The method enables metallic iron to melt at a lower temperature, thereby allowing efficient separation of by-product slag at low temperatures and, in addition, metal iron, which has a significant effect on the quality of product metallic iron.
- the carbon concentration can also be controlled.
- An important technical feature of the prior invention is that when the raw material mixture is heated, reduced, and melted to produce metallic iron, the state of by-product slag in the system in which a carbonaceous reducing agent is present.
- the carburization promoting action by the coexistence of carbonaceous reducing agent and molten slag is not effective only when the total amount of slag is in the molten state. If properly controlled, the carburization of solid reduced iron is promoted and the melting temperature can be lowered.
- the liquid phase ratio is located between a solid phase line and a liquid phase line at a certain temperature on an equilibrium diagram, and is in a solid and a liquid (that is, two phases of a solid phase and a liquid phase).
- the liquid phase ratio of slag is mainly derived from the gangue components contained in the raw material.
- thermodynamic equilibrium relationship of multicomponent system consisting mainly of 0, MgO and FeO derived from iron source.
- the liquid phase ratio can be quantitatively determined by image analysis by observing the behavior of the raw material mixture when heated, reduced, and melted with a high-temperature laser microscope.
- image analysis by observing the behavior of the raw material mixture when heated, reduced, and melted with a high-temperature laser microscope.
- the inventors of the present invention have found that the liquid phase ratio of slag can be controlled during the reduction / melting process of the raw material mixture without any control and relatively difficult control, and Ash content in gangue components, unreduced iron oxide and carbonaceous reductant If the temperature of the initial molten slag required is controlled well, not only can iron metal be produced efficiently, but also the carbon concentration of metal iron. As a result, the present invention has been completed.
- Non-Patent Document 1 Similar to Non-Patent Document 1 described above, even in the direct iron manufacturing method, the carburized molten iron is quickly moved toward the solid reduced iron in the molten slag phase to be combined with the solid reduced iron. Just do it. Then, the high concentration of carbon that has entered the molten iron by carburizing will diffuse into the solid reduced iron as soon as it is combined with the solid reduced iron, increasing the carbon concentration of the entire solid reduced iron. . That is, even in the direct iron manufacturing method, if molten slag is generated at an early stage, the metallic iron produced by the reduction of the molten iron oxide in the molten slag is converted into solid reduced iron by the carbon content of the metallic iron in the molten slag. It becomes a carrier for moving in the direction and accelerates the carburization of solid reduced iron.
- the carbon concentration of the molten iron is 1147 ° C, which is an eutectic point in terms of equilibrium, as is apparent from the thermodynamic phase diagram of the Fe-C system, that is, 4. It can be increased to 3% by mass, and as is clear from the phase diagram, the carbon concentration increases as the temperature of the system decreases to the eutectic point.
- a slag forming component containing unreduced iron oxide derived from an iron source is used. It is possible to generate the melt at as low a temperature as possible, promote the reduction of iron oxide (generation of reduced iron), promote the movement toward solid metal iron, and further accelerate the generation of molten iron by carburization. desirable. That is, it is desirable to lower the temperature at which the melt derived from the slag forming components including iron oxide that is initially formed in the raw material mixture in the heat reduction process (that is, the initial molten slag). In other words, when the raw material mixture is heated, as the reduction proceeds from the outside of the raw material mixture, slag is generated inside the raw material mixture. In this reduction process, the initial molten slag may be produced even if the outside is partially reduced.
- the melting temperature (melting-off temperature) of the solid reduced iron also decreases, so it is possible to lower the operating temperature for producing metallic iron after all. It becomes.
- the components in the molten slag that is, It is fundamental to set the unreduced iron oxide derived from the iron source, the gangue component, and the ash content in the carbonaceous material, which is the slag component).
- the formation temperature of such multicomponent initial molten slag is determined by the thermodynamic equilibrium diagram of multicomponent systems including Si 2 O 3, Al 2 O 3, CaO, MgO, and FeO.
- Fig. 2 shows the equilibrium of SiO-AlO-CaO and SiO-AlO-FeO systems.
- compositional power of molten slag is SiO-AlO-CaO system.
- the composition of Al O is about 20% and the CaOZSiO ratio is about 5Z5.
- Al O is about 15% and the CaOZSiO ratio is about 3
- O content is about 35-50% (more preferably about 40%) and SiO / Al 2 O ratio is about 45Z
- the melting temperature of the four-component slag is the lowest and shows the value.
- each component composition of the slag forming component is adjusted within a changeable range so that the slag composition generated in the heat reduction process becomes the minimum temperature as described above.
- the initial melting slag can be generated at the lowest temperature.
- Specific means for adjusting the components of the slag-forming component include slag-forming components in the raw material components (including gangue components in the iron source, ash in the carbonaceous material, inorganic binder components, etc.) Depending on the method, supplementary addition of deficient CaO, SiO or Al 2 O, etc.
- the ratio of iron oxide in the raw material that can be recovered as metallic iron is expressed as a metallization rate, and the metallization rate is high! Productivity is good! /. Therefore, conventionally, energetic efforts have been paid to how to increase the metallization rate. However, it is extremely difficult to reduce all of the iron oxide source to increase the metallization rate to 100%, and the metallization rate obtained under normal conditions is at most about 90 to 95%, and the rest A few percent of this remains as unreduced iron oxide.
- unreduced iron oxide remaining in the heat reduction process is actively used. That is, by mixing unreduced iron oxide into the slag, the temperature of the initial molten slag is lowered, and the molten unreduced iron oxide mixed in the slag is reduced and carburized. The resulting carburized iron acts as a carrier for carbon in the direction of solid reduced iron. As a result, the total production efficiency of metallic iron can be increased.
- the residual amount of unreduced iron oxide that provides the optimum FeO content is obtained according to the type and amount of the additive for adjusting the slag forming component and the slag component in the raw material mixture.
- the metalization rate of the iron oxide source (the reduction rate of the iron oxide-containing substance) may be controlled. Specifically, adjust the heating temperature pattern or reduction potential and heat the raw material mixture until the target metallization rate is reached! Examples of the adjustment of the heating temperature pattern include control of the temperature, time, or temperature rising rate during heating reduction. Examples of adjustment of the reduction potential include control of the amount of carbonaceous reducing agent, the amount of reducing agent used as a flooring, or the atmosphere gas in the furnace.
- Figure 3 shows a case where heat reduction at 1250 to 1350 ° C was performed using MBR from South America as the iron oxide source (iron ore) and Oak Grove coal from North America as the charcoal.
- the metallization rate of the raw material mixture can be controlled by The amount of residual FeO can be adjusted, and as a result, the content of FeO in the generated slag can be obtained appropriately.
- FIG. 4 shows that the target temperature in the heating and reduction furnace is set to 1400 ° C, the same raw material mixture as above is supplied to this, and the temperature and metal with respect to the elapsed time when the heating reduction is performed.
- 5 is a graph showing the relationship of conversion rate (that is, reduction rate).
- the metallization rate slightly varies depending on the specific characteristics of the heating reduction furnace.
- the metallization rate increases with the elapse of the heating time.
- the conversion rate rises rapidly, and after about 9 minutes, the rate of increase in the metalization rate decreases rapidly.
- the metallization rate reaches approximately 90% by mass when the heating start force is around 8 minutes, and at this point, the amount of acid iron iron remaining in the unreduced state becomes approximately 10% by mass.
- the amount of residual iron oxide is the target content described above (ie, the slag composition corresponding to the target carbon concentration).
- Figure 5 shows that the mass ratio of CaOZSiO in the slag is kept constant at 0.38, and the iron oxide in the slag (
- the initial molten slag generation temperature slag burn-off temperature
- the CO gas generation start temperature accompanying the reduction of molten acid pig iron (FeO) also decreases.
- Figure 6 shows the result of a similar experiment with the CaOZSiO mass ratio in the slag changed to 0.92.
- Fig. 7 is a graph showing the results of investigating the effect of the initial molten slag generation temperature (slag burn-off temperature) on the carbon concentration (C concentration) in the molten metal iron produced (melt-off metal iron) This graph force confirms that the carbon content in the metallic iron as the reduction product increases as the initial molten slag formation temperature (slag melt-off temperature) decreases.
- the initial molten slag generation temperature depends on the slag forming component in the raw material (the gangue component in the iron source and the ash contained in the carbonaceous material) that is first combined with the raw material mixture.
- the slag forming component in the raw material the gangue component in the iron source and the ash contained in the carbonaceous material
- the melting point of the slag of these mixed compositions is reduced in the iron source.
- Add slag-forming components other than gangue components to the appropriate amount at the stage of preparing the raw material mixture, adding the raw material mixture, or heating the raw material mixture (hereinafter sometimes referred to as the addition of a third slag-forming component) ) Do it!
- the iron oxide content in the slag is secured by the iron oxide remaining in the unreduced state during the metallic iron production process. If possible, control the metalization rate of the iron source in the raw material mixture and the heating temperature pattern properly.
- the composition of the slag forming component and the unreduced iron oxide component may be adjusted so that the optimum initial molten slag generation temperature is obtained.
- the initial molten slag composition should be adjusted by adding a third slag-forming component, the metalization rate of the iron source in the raw material, and the heating temperature pattern.
- the control of the initial molten slag generation temperature in carrying out the present invention is performed according to the composition of the appropriate slag forming component according to the composition of the gangue component contained in the iron ore used as the acid iron source. It is possible to adjust by using several iron ores in combination, but it is possible to change the initial molten slag generation temperature according to the gangue component composition contained in the raw ore. Is preferably added.
- the auxiliary materials include quick lime (CaO), limestone (CaCO 3), silica (SiO 2), serpentine (MgO + SiO;), Mn ore (MnO + FeO),
- Bauxite Al 2 O 3
- Al 2 O 3 Al 2 O 3
- a raw material mixture is prepared by blending an acid iron source, a carbonaceous reducing agent, and if necessary, one binder component
- a multi-component phase diagram is obtained from the composition of the gangue component contained in the raw materials.
- the melting temperature is determined on the basis, and an appropriate amount of the above-mentioned acid soot is added to the raw material mixture as an auxiliary raw material so that the target initial molten slag formation temperature can be obtained.
- the molten iron oxide is reduced and carburized as described above, and further, the high-speed movement of the molten iron in the direction of the solid reduced iron and the accompanying carburization by the carbon carrier action, and the burn-off temperature. Therefore, it is necessary for solid metallic iron to cause a sufficient melting point drop due to carburization.
- the carbon concentration of the metallic iron after carburizing is controlled within the range of 0.5 to 4.3 mass%, and the initial molten slag generation temperature is controlled within the range of 1147 to 1500 ° C. preferable.
- the carbon concentration of the metallic iron after the carburization is more preferably controlled within the range of 1.5 to 3.5% by mass, and the initial molten slag generation temperature is preferably 1200 to 1450 ° C. It is more preferable to control within the range.
- the carbon concentration of metallic iron after carburizing should be adjusted according to the amount of carbonaceous reductant added at the raw material preparation stage. What is necessary is just to mix
- the amount of carbonaceous reducing agent is adjusted as described above at the time of mixing the raw materials, the amount of carburizing into metallic iron at the time of carburizing and melting can be adjusted, and finally obtained.
- metal The carbon content of iron can be arbitrarily adjusted as necessary.
- the raw material mixture used in the present invention is a powdered mixed state of both the iron oxide source and the carbonaceous reducing agent so that heating and reduction of the iron oxide with the gas derived from the carbonaceous reducing agent proceed efficiently. It is desirable to use in.
- This raw material mixture can be supplied in a state of being lightly pressed on the hearth.
- the mixture is formed into an arbitrary shape such as a substantially spherical shape, a pricket shape, or a pellet shape.
- a solid reduced iron shell is formed on the outer periphery of the molded body, and the inside can be maintained at a high reduction potential, and the metallization rate is increased. I like it because it can be improved more efficiently.
- the specific apparatus and basic operating conditions for implementing the present invention are basically the same as the apparatus and operating conditions disclosed in Patent Document 1 and the like. Specifically, it is equipped with a circular or donut-shaped rotary hearth, and the raw material mixture supply zone, preheating zone, heating reduction zone, metallic iron melting zone, cooling zone (metallic iron solidification zone), discharge zone in the direction of rotation. It is only necessary to use a heating and reduction furnace equipped with an apparatus capable of continuously carrying out a series of operations from supplying raw materials to heating and reducing, cooling and solidifying and removing the produced metallic iron.
- the composition and carbon content of the slag forming material in the raw material corresponding to the target carbon concentration are set in preliminary experiments, and the optimum initial molten slag during heating reduction is set. Adjust the metalization rate so that the formation temperature is obtained, and ensure the unreduced iron oxide content in the initial molten slag.
- the metallic iron which has been heated and reduced and then carburized and melted and aggregated in a granular form is cooled, the metallic iron which has been aggregated and solidified in a granular form can be obtained.
- the metallic iron can be easily separated by cooling or solidifying the generated slag and sieve, separating, or magnetic separation, etc.
- the initial stage consisting of the gangue component and unreduced iron oxide generated during the reduction and melting process of the raw material mixture.
- the carbon concentration in the obtained metallic iron can be arbitrarily controlled.
- the following secondary effects can be obtained. That is, the carbon content of metallic iron obtained by the method of the present invention increases as the initial molten slag formation temperature decreases. In other words, the lower the operating temperature, the higher the carbon content of metallic iron. Therefore, the amount of heat consumed for heat reduction can be suppressed.
- the molten iron oxide contained in the initial molten slag acts as a carbon carrier for the solid metal iron produced by gas reduction, and the carburization of the solid reduced iron (solid metal iron) proceeds rapidly to dissolve it. Since the fall is promoted, the melting of the solid reduced iron is also significantly accelerated, and the overall production efficiency can be significantly increased.
- the initial molten slag contains unreduced iron oxide as described above.
- the iron oxide is reduced to become metallic iron, and the metallic iron acting as a carbon carrier moves to the solid reduced iron side in the molten slag.
- the composition of the molten slag changes with time. For this reason, in order to produce metal iron more efficiently, it is necessary for metal iron to move smoothly even in a state where the amount of acid iron in the molten slag is reduced. In this respect, it is also preferable to control the melting point of the slag after the metallic iron is generated instead of the generation temperature of the initial molten slag.
- the melting point of the final slag to be controlled (that is, the slag melting temperature) may be determined from the phase diagram based on the average yarn composition of the slag that is finally produced. As a result, even when the reduction reaction proceeds, the final molten slag is produced at a low temperature, so that metallic iron can be produced efficiently.
- the metallization rate during the heat reduction is adjusted in consideration of the initial molten slag generation temperature generated during the heat reduction so that the finally obtained metal iron having the above carbon content is obtained.
- each was set to an appropriate initial molten slag generation temperature (or slag melting temperature, which is the temperature at which the slag is all in one phase of the liquid phase).
- the initial molten slag formation temperature is determined by the slag forming component contained in the raw material and the remaining amount of unreduced iron oxide during heating reduction, but the slag forming component is appropriate! By adding a substance containing, the initial molten slag generation temperature can be lowered.
- Table 3 includes a slag forming component separately in order to secure the initial molten slag generation temperature corresponding to the target carbon concentration of metallic iron obtained in Experimental Example 1 set to about 3%.
- the results of examining the influence of the added amount of CaO on the initial molten slag formation temperature when limestone (CaO) is added as a material to be prepared in the stage of preparing the raw material mixture are shown.
- Two brands used in Experiment 1 were used as charcoal materials, but it can be seen that the initial molten slag generation temperature can be lowered by adding an appropriate amount of CaO in either case.
- the carbon content of the metallic iron obtained in each case is 1.8% when the CaO addition amount in Table 3 is 0.3%, and 1 when the CaO addition amount is 0.4%. It was 2.9% when 7% and CaO content was 2.0%, and 3.5% when CaO content was 4.0%.
- the operation temperature pattern and the residence time of each zone such as heating and reduction are determined, and the initial molten slag generation temperature is further reduced! / ⁇ In this case, it is also effective to appropriately control the initial molten slag generation temperature by adding a separate slag forming component such as CaO as an additive at the stage of charging the raw material mixture or as a slagging agent at the stage of heating the raw material mixture. It becomes.
- a separate slag forming component such as CaO
- the present invention by changing the properties of the carbonaceous reducing agent (carbon material) used as the reducing agent, it is possible to control the initial molten slag generation temperature or to control the remaining amount of unreduced iron oxide during heating reduction. Is also possible.
- the CaO content is added to the charcoal material to increase the CaO content and change the initial molten slag generation temperature.
- Table 4 examined changes in the initial molten slag generation temperature for the above-mentioned three brands of charcoal with the addition of CaO of the amount shown in Table 4 to change the ash content. The results are shown. As is clear from this table, when an appropriate amount of CaO is added to the carbonaceous material, the initial molten slag formation temperature clearly decreases.
- Ca ions in CaO are known to have a catalytic action that increases the reducing ability of the carbonaceous material as an alkali and contributes to improving the reactivity of the carbonaceous material. It can be used to adjust the remaining amount of iron.
- the present invention is a method for producing metallic iron from a raw material mixture containing a carbonaceous reducing agent and an iron oxide-containing substance, and has a predetermined target carbon concentration in metallic iron.
- the initial molten slag that is first produced in the raw material mixture by heating the raw material mixture according to the method, including a gangue component, unreduced iron oxide, and ash in the carbonaceous reducing agent Determining a target generation temperature; preparing the raw material mixture for generating a composition of the initial molten slag according to the target generation temperature; and heating the raw material mixture to Reduction 'Melting and initial melting And a step of producing a lug.
- the target generation temperature of the initial molten slag may be a specific temperature or a temperature range having a specific upper limit value and lower limit value.
- the above-mentioned “specific temperature” is a “temperature higher than the minimum temperature” within the range of each component composition of the slag-forming component that can be changed according to the operational restrictions caused by the equipment and process.
- a slag-forming component may be added to the iron oxide-containing substance in the preparing step.
- a slag forming component may be added to the carbonaceous reducing agent.
- the raw material mixture may further contain an auxiliary material, and in the preparing step, a slag forming component may be blended with the auxiliary material.
- a step of adding an additive containing a slag forming component may be further included before the heating step. Further, in the heating step, a molding agent containing a slag forming component may be added.
- a flux containing a slag-forming component may be added instead of a slag-forming agent, and a flux containing a slag-forming component and a slag-forming component may be added.
- the target generation temperature may be controlled by adding a third slag forming component.
- the necessary slag forming components in the initial molten slag are appropriately replenished in the raw material mixture blending stage, raw material mixture charging stage, or raw material mixture heating stage. As a result, the initial molten slag is generated at the target temperature.
- the target generation temperature can be determined from a multi-component equilibrium state diagram composed of a gangue component, unreduced iron oxide remaining during reduction, and ash in a carbonaceous reducing agent. As a result, if each component composition of the slag forming component is adjusted within a changeable range, the target generation temperature that is the lowest initial molten slag generation temperature in the changeable composition range can be easily determined. .
- the target generation temperature can be determined from the target carbon concentration according to this correspondence relationship by checking in advance the relationship between the generation temperature of the initial molten slag and the carbon concentration in the metallic iron. This allows the metal with the target carbon concentration Iron can be manufactured stably.
- a target content of the unreduced iron oxide in the initial molten slag is determined, and a target reduction rate of the iron oxide-containing substance according to the target content is calculated.
- the heating temperature pattern or the reduction potential may be adjusted and heated until the reduction rate of the iron oxide-containing substance reaches the target reduction rate.
- heating may be performed based on the melting point of slag containing unreduced iron oxide during reduction.
- the gangue component in the raw material mixture, the ash in the carbonaceous reducing agent, and the heat reduction By controlling the amount of unreduced iron oxide remaining, the temperature at which the initial molten slag is formed is controlled. As a result, the carbon concentration in the obtained metallic iron can be adjusted, and metallic iron having a carbon concentration as desired can be obtained efficiently. Further, in the present invention, as described in detail above, molten iron derived from iron oxide (iron oxide-containing substance) mixed from raw ore into molten slag is used as a carbon carrier for carburizing solid reduced iron. As a result, the carburization of the solid reduced iron can be rapidly advanced to allow the solid reduced iron to be melted at a low temperature, and as a result, the productivity can be increased while reducing the heat energy consumed for the production of metallic iron.
- iron oxide iron oxide-containing substance
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/094,607 US20090282950A1 (en) | 2006-01-17 | 2006-11-30 | Process for producing metallic iron |
AU2006335814A AU2006335814B2 (en) | 2006-01-17 | 2006-11-30 | Method for manufacturing metallic iron |
CA2630236A CA2630236C (en) | 2006-01-17 | 2006-11-30 | Method for manufacturing metallic iron |
CN2006800473579A CN101331239B (en) | 2006-01-17 | 2006-11-30 | Process for producing metallic iron |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2006-008743 | 2006-01-17 | ||
JP2006008743A JP4981320B2 (en) | 2006-01-17 | 2006-01-17 | Metal iron manufacturing method |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2007083450A1 true WO2007083450A1 (en) | 2007-07-26 |
Family
ID=38287408
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2006/323928 WO2007083450A1 (en) | 2006-01-17 | 2006-11-30 | Process for producing metallic iron |
Country Status (8)
Country | Link |
---|---|
US (1) | US20090282950A1 (en) |
JP (1) | JP4981320B2 (en) |
CN (1) | CN101331239B (en) |
AU (1) | AU2006335814B2 (en) |
CA (1) | CA2630236C (en) |
RU (1) | RU2388830C1 (en) |
TW (1) | TWI307365B (en) |
WO (1) | WO2007083450A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010261101A (en) | 2009-04-07 | 2010-11-18 | Mitsutaka Hino | Method for producing metallic iron |
CN102803523A (en) * | 2010-03-25 | 2012-11-28 | 株式会社神户制钢所 | Carbon-material-containing iron oxide briquette composition, method for producing same, and method for producing reduced iron using same |
CN102959093B (en) * | 2010-08-30 | 2014-06-04 | 株式会社神户制钢所 | Granular metal iron production method |
KR101293625B1 (en) | 2011-08-26 | 2013-08-13 | 우진 일렉트로나이트(주) | Determination System for FeO Sensing in Molten Slag |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10251724A (en) * | 1997-03-13 | 1998-09-22 | Kobe Steel Ltd | Production of metallic iron and producing equipment therefor |
JP2005048197A (en) * | 2000-08-09 | 2005-02-24 | Kobe Steel Ltd | Method for producing metallic iron |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6506231B2 (en) * | 1996-03-15 | 2003-01-14 | Kabushiki Kaisha Kobe Seiko Sho | Method and apparatus for making metallic iron |
CN1080315C (en) * | 1996-03-15 | 2002-03-06 | 株式会社神户制钢所 | Method and apparatus for making metallic iron |
JPH10195513A (en) * | 1996-12-27 | 1998-07-28 | Kobe Steel Ltd | Production of metallic iron |
US6149709A (en) * | 1997-09-01 | 2000-11-21 | Kabushiki Kaisha Kobe Seiko Sho | Method of making iron and steel |
JP4159634B2 (en) * | 1997-10-23 | 2008-10-01 | 株式会社神戸製鋼所 | Metallic iron manufacturing method and equipment |
JP3848453B2 (en) * | 1998-01-09 | 2006-11-22 | 株式会社神戸製鋼所 | Manufacturing method of metallic iron |
US6413295B2 (en) * | 1998-11-12 | 2002-07-02 | Midrex International B.V. Rotterdam, Zurich Branch | Iron production method of operation in a rotary hearth furnace and improved furnace apparatus |
US6063744A (en) * | 1999-07-22 | 2000-05-16 | Mcquillen; Edwin F. | Cleaning and lubricant formulation for spindles |
JP2001279313A (en) * | 2000-03-30 | 2001-10-10 | Midrex Internatl Bv | Method for producing molten metallic iron |
JP2001342509A (en) * | 2000-06-02 | 2001-12-14 | Kobe Steel Ltd | Method and apparatus for producing metallic iron |
-
2006
- 2006-01-17 JP JP2006008743A patent/JP4981320B2/en not_active Expired - Fee Related
- 2006-11-30 US US12/094,607 patent/US20090282950A1/en not_active Abandoned
- 2006-11-30 CN CN2006800473579A patent/CN101331239B/en not_active Expired - Fee Related
- 2006-11-30 RU RU2008133606/02A patent/RU2388830C1/en not_active IP Right Cessation
- 2006-11-30 AU AU2006335814A patent/AU2006335814B2/en not_active Ceased
- 2006-11-30 WO PCT/JP2006/323928 patent/WO2007083450A1/en active Application Filing
- 2006-11-30 CA CA2630236A patent/CA2630236C/en not_active Expired - Fee Related
- 2006-12-28 TW TW095149418A patent/TWI307365B/en not_active IP Right Cessation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10251724A (en) * | 1997-03-13 | 1998-09-22 | Kobe Steel Ltd | Production of metallic iron and producing equipment therefor |
JP2005048197A (en) * | 2000-08-09 | 2005-02-24 | Kobe Steel Ltd | Method for producing metallic iron |
Also Published As
Publication number | Publication date |
---|---|
CA2630236A1 (en) | 2007-07-26 |
AU2006335814A1 (en) | 2007-07-26 |
TWI307365B (en) | 2009-03-11 |
RU2008133606A (en) | 2010-02-27 |
JP2007191736A (en) | 2007-08-02 |
CA2630236C (en) | 2012-07-31 |
AU2006335814B2 (en) | 2011-04-14 |
JP4981320B2 (en) | 2012-07-18 |
CN101331239B (en) | 2012-03-28 |
RU2388830C1 (en) | 2010-05-10 |
CN101331239A (en) | 2008-12-24 |
TW200730630A (en) | 2007-08-16 |
US20090282950A1 (en) | 2009-11-19 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4330257B2 (en) | Metal iron manufacturing method | |
KR100710943B1 (en) | Process for producing particulate iron metal | |
WO2010117008A1 (en) | Method for producing metallic iron | |
JP4691827B2 (en) | Granular metal iron | |
AU2009234752B2 (en) | Titanium oxide-containing agglomerate for producing granular metallic iron | |
JP5297077B2 (en) | Method for producing ferromolybdenum | |
JP2010229525A (en) | Method for producing ferronickel and ferrovanadium | |
WO2007083450A1 (en) | Process for producing metallic iron | |
JP4540172B2 (en) | Production of granular metallic iron | |
JP5000593B2 (en) | Manufacturing method of granular metallic iron and manufacturing method of molten steel using the metallic iron | |
JP3845893B2 (en) | Metal iron manufacturing method | |
JP5210555B2 (en) | Manufacturing method of granular metallic iron | |
JP2000045007A (en) | Production of metallic iron and device therefor | |
JP2001515138A (en) | Iron and steel making | |
JP3848453B2 (en) | Manufacturing method of metallic iron | |
JP3844873B2 (en) | Metal iron manufacturing method | |
JP3750928B2 (en) | Carburized material and steel making method using the same | |
JP4415690B2 (en) | Method for producing sintered ore | |
JPH10102117A (en) | Production of metallic iron and production equipment thereof | |
KR101448607B1 (en) | Method for manufacturing iron | |
JP2007246970A (en) | Method for operating movable hearth furnace | |
JPH10251725A (en) | Production of metallic iron and producing equipment thereof | |
JPH10102114A (en) | Production of metallic iron and production equipment thereof |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 200680047357.9 Country of ref document: CN |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2006335814 Country of ref document: AU |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2630236 Country of ref document: CA |
|
WWE | Wipo information: entry into national phase |
Ref document number: 12094607 Country of ref document: US |
|
ENP | Entry into the national phase |
Ref document number: 2006335814 Country of ref document: AU Date of ref document: 20061130 Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 2008133606 Country of ref document: RU Kind code of ref document: A |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 06833731 Country of ref document: EP Kind code of ref document: A1 |