JP6994751B2 - Charcoal interior porous ore and its manufacturing method - Google Patents

Description

The present invention relates to a carbonaceous interior porous ore, and more particularly to a carbonaceous interior porous ore containing a level of carbon that enables complete reduction of iron ore and a method for producing the same.

In recent years, the resources of high-grade iron ore, which is a raw material for steelmaking, containing 60% or more of iron have been decreasing. Along with these circumstances, as an alternative and because it is cheaper than high-grade iron ore, the amount of water-of-crystal water-containing ore, which is a poor quality ore, tends to increase more and more. When water of crystallization-containing ore is used as a raw material for iron production, not only it takes time to reduce iron oxide, but also the consumption of coke, which is a reducing agent, increases.

Against this background, for the purpose of using the water-of-crystallized ore as a raw material for iron making, the charcoal interior ore in which the ore and the charcoal are closely arranged has begun to attract attention. When this carbonaceous material interior ore is used, high temperature pretreatment such as sintering becomes unnecessary because it can be reduced at low temperature, and in addition to being able to use powdered ore and carbonaceous material powder, carbonaceous material and ore powder are densely mixed. Since it has the advantage of improving productivity, various methods for producing interior carbonaceous ore have been proposed, and a reduction method using carbonaceous interior ore that does not go through a sintering process has also been studied. It has been done.

For example, Japanese Patent Application Laid-Open No. 2007-77484 (Patent Document 1), which discloses an invention of a method for producing a coalaceous interior agglomerate as a raw material for charging a blast furnace, contains a plurality of types of iron-containing raw materials (iron ore). This is a method of hot-molding a mixture of a powdered mixed iron-containing raw material and a powdered coal material (powdered coal) having softening and melting properties to produce a carbonaceous material interior agglomerate. Disclosed is a production method capable of maintaining or improving both the strength and reducibility of a coalaceous inner agglomerate even when inferior ore such as pisolite ore is used as a compounding raw material for a powdery compounded iron-containing raw material.

In this method, by adjusting the specific surface area of the powdered iron-containing raw material, even if inferior ore such as malamamba ore or pisolite ore is used as the compounding material of the powdered iron-containing raw material, the carbonaceous material inner mass is agglomerated. It is said that both the strength and the reducibility can be maintained or improved, and a carbonaceous interior agglomerate suitable for a raw material to be charged into a blast furnace can be produced at low cost.

However, in the method disclosed in Patent Document 1, iron ore is crushed as necessary to obtain a powdery compound iron ore having a most frequent particle size of about 50 μm, and coal is also crushed as necessary to obtain the powdery compound iron ore. Since it is a powdered coal with a smaller particle size than the most frequent, in addition to the step of crushing the ore and the carbonaceous material, the contact part between the ore and the carbonaceous material stays on the order of μm, and the iron ore is completely reduced. It cannot be said that it is sufficient to obtain a carbonaceous interior porous ore containing a level of carbon that enables the above.

Further, Japanese Unexamined Patent Publication No. 2008-95175 (Patent Document 2) is a patent document that discloses an ore processing method for treating an ore used for iron making and steel making, and "to a porous ore containing an oxide of a specific element. , An ore treatment method comprising contacting an organic liquid or an organic gas containing an organic compound to attach the organic compound to the porous ore. ”Is disclosed.

In the ore treatment method disclosed in Patent Document 2, first, the ore containing water of crystallization is heated and the water of crystallization is dehydrated as steam to generate a porous ore in which the ore is made porous. Next, the porous ore is brought into contact with a dry distillation gas obtained by carbonizing an organic substance such as a biomass resource or an organic liquid such as coal tar to generate a porous ore to which an organic compound such as tar is attached. Further, the porous ore to which the organic compound is attached is heated in an inert atmosphere, and the oxide of the useful element contained therein is reduced by carbon in the organic compound to produce an ore.

The average pore diameter of the porous ore obtained by the method disclosed in Patent Document 2 is 4 nm, and molecules of an organic compound are attached to the pore walls, but the amount of adhesion (carbon precipitation amount) is about 4 wt%. Therefore, with this amount of carbon precipitation, complete reduction to iron is impossible in principle.

Further, Japanese Patent Application Laid-Open No. 2012-62505 (Patent Document 3), which discloses a method for producing a mass in which reduced iron can be obtained by using low-grade iron ore and low-grade carbonaceous material, states that "iron ore and iron ore". A method for producing a mass for iron production by agglomerating a mixture containing a carbonaceous material, wherein the iron ore is a dehydrated iron ore obtained by heating and dehydrating an iron ore containing 5% by mass or more of crystalline water. As the carbonaceous material, a method for producing an agglomerate, which comprises preparing a carbonaceous material containing 20% by mass or more of a substance having a boiling point of 200 to 500 ° C. and agglomerating a mixture thereof, is disclosed. ..

According to this method, by dehydrating the water-of-crystallized iron ore, voids with an opening diameter of about 0.8 nm are formed in the iron ore, and the carbonaceous material is adsorbed in these voids. There is an advantage that the proximity of the carbonaceous material at the nano level is realized and high-speed reduction at low temperature is possible. However, according to the method disclosed in Patent Document 3, there is no description that carbon precipitation of 18 wt% or more, which is a level of carbon precipitation amount that does not require an additional reducing agent and a fuel for heat compensation for reduction, is possible. , Complete reduction of iron ore cannot be achieved.

By the way, one of the ores containing water of crystallization is goethite (α-FeOOH) ore. This goethite ore is a kind of hydroxide mineral also called goethite, and is an ore which is a main component of so-called limonite together with lepidocrocite (γ-FeOOH), and is expected as a substitute material for high-grade iron ore.

Gesite ore is easily pulverized and needs to be coarsened by a sintering process using coke in order to be put into a blast furnace. However, coke itself is produced by steaming coal at a high temperature for a long time. In addition, since the above-mentioned sintering process itself requires a high temperature of 1200 ° C. or higher for a long time (about 20 hours), the sintering process for coarsening Gesite ore consumes an extremely large amount of energy. It has to be a process to do.

Further, even if the above-mentioned conventional method is applied to goethite ore, there is a limit to the amount of carbon that can be contained, and it is not possible to achieve 18 wt% or more required for complete reduction of iron ore.

Japanese Unexamined Patent Publication No. 2007-77484 Japanese Unexamined Patent Publication No. 2008-95175 Japanese Unexamined Patent Publication No. 2012-62505

In conventional ironmaking, high-grade iron ore and high-grade coal are steam-baked at 1200 ° C. for 20 hours and then heat-treated at a high temperature of 1200 to 1400 ° C. for a long time to produce iron. In recent years, the ironmaking industry has been focusing on the development of low-energy ironmaking methods using goethite ore, which is a low-grade iron ore, and coal tar, which is a by-product and waste.

However, a method for producing an iron-making raw material containing 18 wt% or more of carbon required for complete reduction of iron ore in goethite ore has not been established, and an iron-making process for synthesizing a large amount of Fe by a low-temperature process. Is still undeveloped.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to allow water of crystallization ore such as Gesite ore to contain carbon at a level capable of complete reduction of iron ore. The purpose is to provide new technology for carbonaceous material interior ore and to realize short-time reduction of carbonaceous material interior ore.

Means to try to solve the problem

In order to solve the above problems, the crystalline water-containing ore according to the present invention is a porous ore having a plurality of pores inside, and the inner diameter of the pores is at the nanometer level, and a carbonaceous material is contained therein. The surface of the porous ore is coated with a carbonaceous material, and the carbon content is 18 wt% or more.

Preferably, the porous ore is a porous goethite ore.

The method for producing a porous carbonaceous material interior according to the present invention includes the following steps.
Step 1: The ore containing crystalline water is heated to desorb the crystalline water to form pores having an inner diameter of nanometer level inside the ore. Step 2: The ore that has undergone step 1 is impregnated into the tar-containing solution. Step 3: A step of coating the surface of the ore with a tar component and filling the inside of the pores with the tar component. Step 3: A step of heat-treating the ore that has undergone step 2 to carbonize the tar component.

Preferably, the heating temperature in step 1 is 800 ° C. or lower.

Further, preferably, the step 3 is performed in an inert gas at a temperature of 500 ° C. or lower.

Further, preferably, the water of crystallization-containing ore is goethite ore.

The method for reducing water of crystallization-containing ore according to the present invention includes the following steps.
Step 1: The crystal water-containing ore is heated to desorb the crystal water to form pores with an inner diameter of nanometer level inside the ore. Step 2: The ore that has undergone step 1 is impregnated into the tar-containing solution. Then, the surface of the ore is coated with the tar component, and the inside of the pores is filled with the tar component. Step 3: The ore that has undergone step 2 is heat-treated to carbonize the tar component. Step 4: Step Step of heat-treating the ore that has passed through 3 and reducing the ore by utilizing the combustion heat of the carbonized component.

Preferably, the heating temperature in step 1 is 800 ° C. or lower.

Further, preferably, the step 3 is performed in an inert gas at a temperature of 500 ° C. or lower.

Further, preferably, the step 4 is performed at a temperature of 1000 ° C. or lower.

Further, preferably, the water of crystallization-containing ore is goethite ore.

In the method for producing a porous carbonaceous material interior according to the present invention, a so-called combustion synthesis method is used in which the heat generated when the carbon deposited on the surface of the ore burns is conducted inside the ore and the reduction reaction is self-propagated. ing.

Since the water of crystallization water-containing ore according to the present invention produced by such a method has a carbon content of 18 wt% or more, it does not require fuel or coke for reducing iron ore, which was required in the conventional method. Become.

It is a figure which conceptually explains the manufacturing process of the carbonaceous material interior porous ore which concerns on this invention. It is SEM image (a) and EDS mapping (b) in the same field of view of the carbonaceous material interior porous ore which concerns on this invention. It is an SEM image (a) in which the observation region shown in FIG. 2 is observed at a higher magnification, and EDS mapping (b) of carbon (C) in the same field of view. In addition, in order to compare the distribution state of carbon, the SEM image (c) of the ore interiored with carbonaceous material by the conventional method (CVI method) and the EDS mapping (d) of carbon (C) in the same field of view are also shown. It is a figure which conceptually explained the structural change of the ore in the steps 1 to 3 of the manufacturing method of the carbonaceous material interior porous ore. FIG. (A) is a conceptual diagram of an apparatus system for performing a combustion synthesis reaction with a porous ore containing a carbonaceous material according to the present invention, and FIG. (B) is an example of a temperature profile thereof. It is an XRD pattern of an ore treated by changing the oxygen concentration in an atmosphere in the range of 15 to 100 vol%. SEM images and EDS mapping of the carbonaceous interior porous ore before and after the combustion synthesis reaction. It is a figure for conceptually explaining the mechanism of the combustion synthesis reaction of the carbonaceous material interior porous ore which concerns on this invention. It is an XRD pattern of an ore treated by changing the heat treatment temperature in the range of 700 to 900 ° C. It is an XRD pattern of each ore for confirming the effect of oxygen in the atmosphere of the reduction heat treatment. It is a figure which showed the measured value of the sample temperature during reduction heat treatment, and the temperature change per hour. XRD pattern of goethite ore, reagent Fe ₂ O ₃ , and high-grade ore before and after carbonization. XRD pattern of goethite ore, reagent Fe ₂ O ₃ , and high-grade ore after reduction treatment. It is a chart of the analysis result of the gas generated during the reduction treatment of the example.

Hereinafter, the carbonaceous interior porous ore according to the present invention and a method for producing the same will be described with reference to the drawings. In the following, the porous ore will be described as being a porous goethite ore.

FIG. 1 is a diagram conceptually illustrating a manufacturing process of a porous carbonaceous material interior according to the present invention, in which the crystal water-containing ore is heated to desorb the crystalline water, and the inner diameter of the ore is inside the ore. Step 1 to form nanometer-level pores, and the ore that has undergone step 1 is impregnated into a tar-containing solution to coat the surface of the ore with a tar component and to add a tar component to the inside of the pores. It includes a step 2 of filling and a step 3 of heat-treating the ore that has undergone the step 2 to carbonize the tar component.

First, in the above step 1, the water of crystallization ore 1 is heated at a temperature of 800 ° C. or lower to separate (dehydrate) the water of crystallization in the ore. From the viewpoint of low temperature treatment, the temperature is preferably 500 ° C. or lower, and the lower limit of the treatment temperature is about 250 ° C. In this treatment, the goethite ore 1 is sized in advance to have an individual diameter of about 1 to 2 mm, and for example, the iron component is about 57 wt% and the water of crystallization component is about 8.8 wt%. The heat treatment time is, for example, about 24 hours. By this heat treatment, the following reaction proceeds, and a porous ore 10 having pores having an inner diameter of nanometer level (10 nm or less, for example, about 3 to 4 nm) is obtained (FIG. 1 (a)). )).

2FeOOH → Fe ₂ O ₃ + H ₂ O

The porous ore 10 thus obtained can also be used as a catalyst material by utilizing the high specific surface area.

The porous ore 10 thus obtained is impregnated in the tar-containing solution in step 2, the surface is coated with the tar component, and the inside of the pores is filled with the tar component (FIG. 1 (FIG. 1). b)). The tar-containing solution 20 is, for example, a mixed solution of coal tar and toluene. For example, coal tar having a fixed carbon component of 32 wt%, an ash content of 0.04 wt%, and a water content of 0.15 wt% is used as a reagent toluene. , A mixture of 1: 1 by weight. The impregnation time is, for example, about 5 to 10 minutes.

When such impregnation is performed, the surface of the porous ore 10 is covered with the tar component, and the tar component is also filled in the pores formed inside.

Subsequently, with the porous ore 10 impregnated in the tar-containing solution 20, heat treatment is performed with the heater 30 in an inert atmosphere (for example, Ar atmosphere). The heat treatment temperature is set to a temperature of 500 ° C. or lower, and the heat treatment time is, for example, 1 hour in the case of heat treatment at 500 ° C. By this heat treatment, the tar component covering the surface of the porous ore 10 and the tar component filled in the pores are carbonized, and carbon precipitation occurs.

Since the porous ore 10 after the completion of this step 3 is mutually aggregated, it is preferable to re-size the individual diameters to about 1 to 2 mm.

FIG. 2 shows an SEM image (FIG. 2 (a)) of the carbonaceous interior porous ore obtained through the above process and EDS mapping of iron (Fe) and carbon (C) in the same field of view (FIG. 2 (b)). )). As is clear from the EDS mapping in FIG. 2 (b), carbon precipitation is clearly observed on the surface of the porous ore.

FIG. 3 is an SEM image (FIG. 3 (a)) in which the observation region shown in FIG. 2 is observed at a higher magnification, and EDS mapping of carbon (C) in the same visual field (FIG. 3 (b)). In addition, for comparison of the distribution state of carbon, the SEM image (FIG. 3 (c)) of the ore interiored with carbonaceous material by the conventional method and the EDS mapping of carbon (C) in the same field of view (FIG. 3 (d)) are also shown. rice field.

In the carbon material inner porous ore according to the present invention, not only the remarkable carbon precipitation in the surface region indicated by the circle in FIG. 3 (b) but also the carbon caused by the carbonization of the tar component filled in the pores. Precipitation can also be confirmed. On the other hand, in the ore interiorized with carbonaceous material by the conventional method, carbon precipitation can hardly be confirmed not only in the surface region but also in the inside of the ore. As is clear from this comparison, the carbonaceous interior porous ore according to the present invention can contain a large amount of carbon.

As described above, according to the present invention, it is a porous ore having a plurality of pores having an inner diameter of nanometer level inside, and the inside of the pores is filled with a charcoal material and the surface is coated with the charcoal material. Porous ore with carbonaceous interior can be obtained. Since the carbon content of this carbonaceous interior porous ore is 18 wt% or more, it is a carbonaceous interior porous ore containing a level of carbon that enables complete reduction of iron ore.

It can be calculated stoichiometrically that the carbon content of the carbonaceous interior porous ore is 18 wt% or more.

That is, when calculated according to the reaction formula (Fe ₂ O ₃ + 3C = Fe + 3CO), the figure of 18.3955% is obtained (3x12 / (2x55.85 + 3x16 + 3x12) x100 = 18.3955%). The present inventors have measured the actual carbon content by elemental (C, H, N) analysis and confirmed that the Geusite ore contains an average of 24.4 wt% carbon.

FIG. 4 is a diagram conceptually explaining the structural change of the ore in the steps 1 to 3 of the method for producing the porous carbonaceous material interior porous ore described so far.

The water of crystallization ore 1 (FIG. 4A) is heated at a temperature of 800 ° C. or lower (for example, a temperature in the range of 250 to 500 ° C.) to separate (dehydrate) the water of crystallization in the ore. As a result, a porous ore 10 in which pores having an inner diameter of nanometer level is formed can be obtained (FIG. 4 (b)).

When the obtained porous ore 10 is impregnated into a tar-containing solution, the surface is coated with the tar component 11 and the inside of the pores is also filled with the tar component 11 (FIG. 4 (c)).

Then, by heat-treating the porous ore 10 in a state of being impregnated in the tar-containing solution, the tar component covering the surface of the porous ore 10 and the tar component filled in the pores are carbonized and carbonized. Twelve precipitation occurs (FIG. 4 (d)).

Since the carbon content of the carbonaceous interior porous ore according to the present invention is 18 wt% or more, no fuel or coke is required to reduce the iron ore.

Since the carbon content of the carbonaceous interior porous ore obtained by the conventional method is low, it is impossible to completely reduce the ore to iron alone, and as can be understood from the reaction formula below, additional reducing agents and reductions are possible. Requires heat compensation fuel for.

Fe _x O + C (contains) + C (addition) = Fe + CO-Q ₁ kJ
Fuel for heat compensation + O ₂ = CO ₂ + H ₂ O + Q ₂ kJ

That is, in the above reaction formula, it is necessary to compensate the heat absorption amount for Q ₁ kJ with the heat (Q ₂ kJ) generated by the combustion using the heat compensation fuel.

When the carbon content of the carbonaceous interior porous ore increases to about 10 wt%, complete reduction of the ore to iron is possible, but as can be understood from the reaction formula below, heat compensation for reduction is possible. Fuel is needed.

Fe _x O + C (contains) = Fe + CO-Q ₃ kJ
Fuel for heat compensation + O ₂ = CO ₂ + H ₂ O + Q ₂ kJ

That is, in the above reaction formula, it is necessary to compensate the heat absorption amount for _Q3 kJ with the heat ( _Q2 kJ) generated by the combustion using the heat compensation fuel.

When the carbon content exceeds 18 wt% as in the carbonaceous material interior porous ore according to the present invention, not only the complete reduction from the ore alone to iron is possible, but also as can be understood from the following reaction formula. Not only is the heat of combustion of the precipitated carbon capable of compensating for the heat of reduction, but it is also a so-called combustion synthesis reaction in which self-propagation of the reaction occurs. It becomes unnecessary.

Fe _x O + C (contains) = Fe + CO-Q ₃ kJ
C (contains) + O ₂ = CO ₂ + H ₂ O + Q ₄ kJ

That is, in the above reaction formula, the heat ( _Q4 kJ) generated by combustion using carbon contained in the carbonaceous interior porous ore self-compensates for the amount of heat absorbed by _Q3 kJ.

FIG. 5 (a) is a conceptual diagram showing an example of an apparatus system for performing a combustion synthesis reaction with the carbonaceous material inner porous ore according to the present invention, and FIG. 5 (b) is an example of the temperature profile thereof. The series of reactions is carried out while flowing an inert gas containing about 15 to 25 vol% oxygen (for example, Ar gas containing 25 vol% oxygen) at 1 liter / min. The temperature is raised to 900 ° C. at a rate of 20 ° C./sec, held at that temperature for 10 seconds, and then naturally cooled.

FIG. 6 shows the XRD pattern of the ore treated by changing the oxygen concentration in the atmosphere during the combustion synthesis reaction in the range of 15 to 100 vol%. The peaks with the symbols H, M, W, I, and F shown in the chart are diffraction peaks from Fe ₂ O ₃ , Fe ₃ O ₄ , FeO, Fe, and Fe ₂ SiO ₄ , respectively. Although the ratio of metallic iron is different, it can be confirmed that metallic iron is produced at any oxygen concentration.

FIG. 7 is an SEM image and EDS mapping of the carbonaceous interior porous ore before and after such a combustion synthesis reaction. (A) and (b) of FIG. (A) are SEM images and EDS mapping of the carbonaceous inner porous ore before the combustion synthesis reaction, respectively, and (a) and (b) of FIG. SEM image and EDS mapping of the carbonaceous interior porous ore after the reaction.

From the comparison of the EDS mappings in FIGS. 7A and 7B, it can be seen that the carbon film having a thickness of 100 to 500 μm observed on the surface before the combustion synthesis reaction has almost disappeared during the combustion synthesis reaction. ..

FIG. 8 is a diagram for conceptually explaining the mechanism of the combustion synthesis reaction of the carbonaceous interior porous ore according to the present invention. When the carbon-12-precipitated carbon-12-precipitated carbon-12-precipitated carbon-12-containing porous ore 10 according to the present invention is heat-treated in an oxygen-containing atmosphere, the carbon-12 precipitated on the surface first reacts with oxygen. To generate heat. The heat is transferred to the inside of the ore and promotes the reduction of the iron ore by the carbon filled in the pores. In other words, as already explained, the heat ( _Q4 kJ) generated by combustion using carbon contained in the porous ore inside the carbonaceous material self-compensates for the amount of heat absorbed by _Q3 kJ. Finally, although carbon-12 and iron oxide 13 remain locally, an ore containing metallic iron as a main component can be obtained.

That is, in the present invention, the crystal water-containing ore is heated to desorb the crystalline water to form pores having an inner diameter of nanometer level inside the ore, and the ore that has undergone the step 1 is contained in a tar-containing solution. The step 2 of impregnating the ore with a tar component and filling the inside of the pores with the tar component, and the step 3 of heat-treating the ore that has undergone the step 2 to carbonize the tar component. It is also a method for reducing crystalline water-containing ore, which comprises a step 4 of heat-treating the ore that has undergone the step 3 and reducing the ore by utilizing the combustion heat of the carbonized component.

The above step 4 is executed at a temperature of 1000 ° C. or lower, for example, 900 ° C. FIG. 9 shows the XRD pattern of the ore treated by changing the heat treatment temperature in the range of 700 to 900 ° C., and the peaks with the symbols H, M, W, I, and F shown in the chart are Fe ₂ O ₃ , respectively. It is a diffraction peak from Fe ₃ O ₄ , Fe O, Fe, and Fe ₂ SiO ₄ . Although the ratio of metallic iron is different, it can be confirmed that metallic iron is produced in each case.

[Confirmation of the effect of oxygen in the atmosphere of reduction heat treatment]
The effect of oxygen in the atmosphere when performing the above reduction heat treatment was confirmed. In the examples, as described above, Ar gas containing 25 vol% oxygen was circulated at 1 liter / min. On the other hand, in Comparative Example 1, pure Ar gas was circulated at 1 liter / min, and in Comparative Example 2, Ar gas containing 20 vol% hydrogen was circulated at 1 liter / min. The combustion synthesis reaction device system and the temperature setting profile are as shown in FIG. 5, and 0.1 g of goethite carbonaceous interior porous ore was subjected to a reduction heat treatment.

FIG. 10 is an XRD pattern of each ore after the reduction treatment. The peaks with the symbols H, M, W, I, and F shown in the chart are diffraction peaks from Fe ₂ O ₃ , Fe ₃ O ₄ , FeO, Fe, and Fe ₂ SiO ₄ , respectively. As is clear from a comparison of the three charts, the heat treatment in an oxygen-containing atmosphere significantly promotes the reduction reaction.

FIG. 11 is a diagram showing an actually measured value of the sample temperature during the reduction treatment and a temperature change (dT (° C.) / dt (sec)) per hour. In Comparative Example 1 and Comparative Example 2, the sample temperature is almost the set temperature, whereas in the example, the sample temperature rises sharply from around the time when the sample temperature reaches 800 ° C. and reaches about 1200 ° C. It can be read that it is. This temperature rise is due to the heat generated by the combustion of carbon deposited on the surface.

[Confirmation of the effect of the type of raw material ore]
We confirmed the effect of the type of ore used as a starting material. The example uses goethite ore as a starting material as described above. On the other hand, in Comparative Example 3, the reagent Fe ₂ O ₃ was used, and in Comparative Example 4, high-grade ore was used. These were evaluated by XRD before and after the carbonization treatment and before and after the reduction treatment. In each case, in the reduction heat treatment, Ar gas containing 25 vol% oxygen was circulated at 1 liter / min, and the treatment temperature was 900 ° C.

FIG. 12 is an XRD pattern of each ore after carbonization treatment. In each case, only the peak of Fe ₂ O ₃ is observed before the reduction treatment, but the peak of Fe ₃ O ₄ is observed after the reduction treatment. Comparing the three, the largest amount of Fe ₃ O ₄ is produced in the examples.

FIG. 13 is an XRD pattern of each ore after the reduction treatment. The peaks with the symbols H, M, W, I, and F shown in the chart are diffraction peaks from Fe ₂ O ₃ , Fe ₃ O ₄ , FeO, Fe, and Fe ₂ SiO ₄ , respectively. As is clear from a comparison of the three charts, the example using goethite ore as a starting material can be reduced to iron, while the ones of Comparative Example 3 and Comparative Example 4 show the formation of metallic iron. Not.

This is because in the example, pores are formed inside the ore and carbon is deposited inside the pores, whereas in the reagent Fe ₂ O ₃ and high-grade ore, water of crystallization is not contained. It is considered that this is because the ore does not have holes and the contact area between the ore and carbon inside the ore is small.

[Analysis of gas generated during reduction processing]
FIG. 14 is a chart of the analysis results of the gas generated during the reduction treatment of the above-mentioned example. In the region shown in (1) in the figure, the amount of O ₂ decreases and the amount of CO ₂ increases. Further, in the region shown in (2) in the figure, CO generation delayed from the above CO ₂ generation is observed. This CO generation is derived from the direct reduction of ore. The CO generation in (2) is delayed from the CO ₂ generation in (1) because the combustion heat generated by the reduction on the surface is transferred to the inside of the ore and there is a slight time lag for the reduction reaction to proceed inside. Is.

As described above, in the present invention, by heating the carbonaceous inner porous ore produced by the tar impregnation method at high speed under oxygen flow, reduction to metallic iron is realized in an extremely short time and at a low temperature. .. Specifically, a mixed solution of coal tar and toluene is impregnated with dehydrated porous iron ore to deposit carbon inside the pores and on the outer surface of the ore. By heating the produced carbonaceous interior porous ore for a short time under oxygen flow, the carbon on the outer surface first begins to burn. The heat generated by this combustion is conducted to the inside of the ore, the inside of the ore becomes high temperature, and the reduction proceeds to become metallic iron.

A brief comparison between the method for producing a porous carbonaceous material interior porous ore according to the present invention and the prior art 1 (blast furnace method) and the prior art 2 (low-grade ore utilization method) is as follows.

Regarding ore, in the prior art 1, it is necessary to use high-grade iron ore and to input a large amount of energy in iron making, whereas in the prior art 2 and the present invention, the low-grade iron ore is practically used. And it is possible to suppress the amount of energy input.

Regarding the carbonaceous material, in both the prior arts 1 and 2, it is necessary to steam and bake expensive strong caking coal at a high temperature (about 1200 ° C.) for a long time (about 20 hours) to make coke. In the present invention, the coke ratio can be reduced because coal tar and biomass tar, which are viscous oily substances as by-products or waste, can be used as a carbonaceous material for reduction.

Regarding the reaction temperature and time during iron making, the prior arts 1 and 2 both require several hours and 30 minutes of reaction time at a high temperature of 1200 to 1400 ° C, respectively, whereas in the present invention, the reaction time is 1000 ° C or less. The temperature is as low as (for example, about 700 to 900 ° C.) and about 10 seconds, which is an extremely short time.

Regarding the reduction mechanism, those of the prior art 1 and 2 are indirect reduction by coke combustion and carbon monoxide (CO) derived from the Budwar reaction (CO ₂ + C⇔2CO), whereas the one of the present invention is an ore. High-speed reduction is realized because it is a direct reduction by the ore and the carbonaceous material placed in close proximity based on the combustion synthesis mechanism that utilizes the heat generated when the carbon deposited on the surface of the surface is burned.

As described above, the carbon precipitation amount of the carbonaceous material interior ore is less than 5 wt% even in the prior art 2, whereas the carbon precipitate of the present invention is 18 wt, which is required for the complete reduction of iron ore. % Or more can be achieved.

According to the present invention, fuel and coke for reducing iron ore, which are required in the conventional one, are not required.

1 Goethite ore 10 Carbonaceous interior porous ore 11 Tar component 12 Carbon 13 Iron oxide 20 Tar-containing solution 30 Heater

Claims (9)

It is a porous ore having a plurality of pores inside, and the inner diameter of the pores is at the nanometer level, and the inside thereof is filled with a carbonaceous material, and the surface of the porous ore is covered with the carbonaceous material. The carbon content is 18 wt% or more.
Charcoal interior porous ore. The carbonaceous interior porous ore according to claim 1, wherein the porous ore is a porous goethite ore. A method for producing a porous carbon ore with a carbonaceous material interior, which comprises the following steps.
Step 1: The ore containing crystalline water is heated to desorb the crystalline water to form pores with an inner diameter of nanometer level inside the ore. Step 2: The ore that has undergone step 1 is impregnated into the tar-containing solution. The surface of the ore is coated with the tar component, and the inside of the pores is filled with the tar component. Step 3: The ore that has undergone step 2 is heat-treated in an inert gas at a temperature of 500 ° C. or lower . Step of carbonizing the tar component The method for producing a carbonaceous interior porous ore according to claim 3, wherein the heating temperature in the step 1 is 800 ° C. or lower. The method for producing a porous carbonaceous material interior according to any one of claims 3 or 4 , wherein the water of crystallization-containing ore is goethite ore. A method for reducing water of crystallization-containing ore, which comprises the following steps.
Step 1: The crystal water-containing ore is heated to desorb the crystal water to form pores with an inner diameter of nanometer level inside the ore. Step 2: The ore that has undergone step 1 is impregnated into the tar-containing solution. Then, the surface of the ore is coated with a tar component, and the inside of the pores is filled with the tar component. Step 3: The ore that has undergone step 2 is heat-treated in an inert gas at a temperature of 500 ° C. or lower . Step 4: Carrying the tar component Step 4: A step of heat-treating the ore that has undergone step 3 and reducing the ore by utilizing the combustion heat of the carbonized component. The method for reducing water of crystallization-containing ore according to claim 6 , wherein the heating temperature in step 1 is 800 ° C. or lower. The method for reducing water of crystallization water-containing ore according to claim 6 , wherein the step 4 is carried out at a temperature of 1000 ° C. or lower. The method for reducing a porous carbonaceous material interior according to any one of claims 6 to 8 , wherein the water of crystallization-containing ore is goethite ore.

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