JP5540859B2 - Carbon steel interior agglomerate for iron making and method for producing the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an iron-making carbonaceous material agglomerated ore used as an iron-making raw material in a blast furnace and the like and a method for producing the same.

In blast furnaces and the like, iron-containing raw materials such as iron ore and sintered ore are currently used as main raw materials. For example, the sintered ore is composed of iron ore having a particle size of 10 mm or less, a secondary raw material made of SiO ₂ containing raw material made of silica, serpentine, refined nickel slag, etc., CaO containing raw material such as limestone, etc., and powder coke A solid fuel, which is a coagulation material such as coal or anthracite, is mixed and granulated using a drum mixer, etc. after adding an appropriate amount of moisture, and then fired with a sintering machine, and the resulting sintered cake is crushed and sized. Thus, it is a kind of agglomerated ore obtained by recovering a product having a certain particle size or more as a product sintered ore.

  By the way, the iron mill is a place where iron oxides such as dust and sludge containing metallic iron are generated. Iron oxides such as these metal iron-containing dusts are useful iron resources and are promising as raw materials for agglomeration. Conventionally, as a method of effectively using such iron oxide as a raw material for agglomeration, there is a technique as disclosed in Patent Document 1; This iron-making raw material pellet is made from iron-containing dust, etc., and added to this is a coal or coke or other coal and starch as a binder, kneaded and granulated, and then fired into agglomerated ore Is.

  In recent years, with regard to the concept of raw material processing in steelworks, agglomerated minerals, in which iron resources such as iron ore and dust and carbon materials such as coke are closely arranged, are attracting attention. The reason for this is, for example, when an iron ore raw material and a carbon material are arranged close together in one agglomerate, a reduction reaction (exothermic reaction) on the iron ore side and a gasification reaction (endothermic reaction) on the carbon material side occur. This is because it is repeated at a high speed, so that the iron-making efficiency is improved and the furnace temperature in a blast furnace or the like can be lowered. In this regard, the technique described in Patent Document 1 is a method for simply producing iron-containing raw materials for iron making by firing iron-containing dust in the presence of coke, and the charcoal contained in the pellets during production. The material is burnt down, and in reality, the iron-containing raw material such as iron ore and the carbonaceous material are not closely arranged. In addition, for the purpose of close arrangement, simply reducing the particle size of coke or iron ore would increase the resistance of gas to propagate heat, resulting in a decrease in reaction rate and reduced iron production efficiency. End up.

  On the other hand, several techniques aiming at the proximity | contact arrangement | positioning of an iron ore and carbon | charcoal material are proposed conventionally (patent document 2, patent document 3, patent document 4, patent document 5). These technologies are basically made by mixing iron-containing raw materials (iron ore, etc.) and coal, then hot forming and agglomerating them, or raw materials for iron making in blast furnaces etc. with raw particles remaining without firing. It is a method to use as. However, these technologies are non-fired agglomerates made of a homogeneous mixture or multi-layered granulated material. Therefore, when this is used in a blast furnace or the like, dehydration powder or reduced powdering is caused. Since the air permeability is hindered, there is a problem that the amount used is limited.

  On the other hand, as an example of a solution without the above-mentioned problems possessed by the conventional techniques (Patent Documents 2 to 5), the one disclosed in Patent Document 6 is an iron source containing metallic iron and / or carbon A high-temperature fired agglomerate is proposed in which a multi-layered agglomerate with a raw material as a core and iron oxide coated around the core is fired in an oxidizing atmosphere at 300 to 1300 ° C.

JP 2001-348625 A Japanese Patent No. 3502008 Japanese Patent No. 2502011 JP 2005-344181 A JP 2002-241853 A JP-A-10-183262

  In the case of each prior art as described in Patent Documents 1 to 6 in the production of iron agglomerates, as mentioned above, the strength is insufficient or the powder is severely pulverized. There are problems that it is easy to invite, and that productivity is low and low temperature reduction is difficult because high temperature firing is required.

  The present invention is a technique developed by earnestly researching and overcoming the above-mentioned problems of the prior art, and the object is to have an appropriate size and sufficient strength as a steelmaking raw material. The purpose is to propose a technique for obtaining an agglomerated carbonaceous material agglomerate in which a reactive structure, an iron-containing raw material capable of low-temperature reduction, and a carbonaceous material are arranged in close proximity.

The present invention is to solve the above problems, in order to achieve the intended purpose, the iron-containing raw material formed by coating the iron oxide powder to the outside of the oxidation of iron powder or iron ore fines, of -3mm size of It is an agglomerate containing coke powder in a dispersed state, and the outer layer portion of the iron-containing raw material in the agglomerate has an oxidation degree Io calculated by the following formula, and an average oxidation degree Io (ave) of 0. It is a carbonaceous material-incorporated agglomerated mineral for iron making, comprising an iron oxide shell having a low oxidation degree of less than 92 .
Record
Io = [(FeO% × 0.223) + (Total Fe% −Fe% made of metal)
-FeO% × 0.777) × 0.430] / (total Fe% × 0.430)

Further, the present invention relates to the production of a carbonaceous material agglomerated ore containing iron material in an interior state in an iron-containing raw material formed by coating iron oxide powder or iron oxide powder on the outside of the iron oxide powder or iron ore powder. a stone powder and a carbonaceous material, mixing granulation using a granulator, then coated with a metallic iron-containing iron oxide powder on the outer surface of the granules, the degree of oxidation Io calculated by the following equation, A method for producing a carbonaceous material-containing agglomerated ore for iron making, characterized in that a low oxidation degree iron oxide shell having an average oxidation degree Io (ave) of less than 0.92 is formed.
Record
Io = [(FeO% × 0.223) + (Total Fe% −Fe% made of metal)
-FeO% × 0.777) × 0.430] / (total Fe% × 0.430)

Moreover, in the agglomerated mineral and the production method thereof in the present invention,
(1) the oxidation Tetsukara of low oxidation degree of iron oxide powder Tona Rukoto containing at least metallic iron,
(2) having a hard thin layer made of iron oxide having a high degree of oxidation on the outer surface of the iron oxide shell;
(3) that the iron oxide shell, are composed primarily of steelworks dust generated or mill scale,
(4) After the formation of the iron oxide shell, an oxidation treatment is performed by heating in the atmosphere at a temperature of 200 ° C. or more and less than 300 ° C. for 0.5 to 5 hours, so that only the surface of the iron oxide shell has a high degree of oxidation. Forming a hard thin layer of iron oxide,
However, this is a more preferable means for solving the above problems.

According to the carbonaceous material-incorporated agglomerated mineral according to the present invention and the method for producing the same, it is iron oxide having a low degree of oxidation because it contains at least metallic iron and / or inferior iron ore powder, By using low-oxidation iron oxide powders such as various dusts and mill scales generated at steelworks, and further by oxidizing and firing raw agglomerated ore, it is sufficient for use as a raw material for blast furnaces, etc. In addition to having strength, it is possible to easily obtain a carbonaceous material-incorporated agglomerated mineral in which iron oxide and a carbonaceous material are arranged in proximity. As a result, when such agglomerated ore is used as a raw material for iron making, it leads to an improvement in reaction efficiency, a reduction in furnace temperature, a reduction in fuel ratio, and a reduction in iron making cost.
In addition, according to the present invention, the thickness of the low oxidation iron oxide shell that is always located on the outer surface and becomes the outer layer is set to 1 to 15 mm, so that the size of the carbonaceous material agglomerated ore is about 20 to 25 mm. A material having the most suitable size as a raw material used in a blast furnace or the like can be obtained.
Furthermore, according to the present invention, since the outermost layer portion of the iron oxide shell has a thin and hard thin layer by oxidation treatment, an agglomerate with high strength can be obtained.

It is explanatory drawing which shows the relationship between the distance between carbon | charcoal material-iron containing raw materials, and reaction rate. It is explanatory drawing which contrasts the reduction reaction and gasification reaction between the carbonaceous material-iron-containing raw materials of the conventional blast furnace phenomenon and the invention example. It is explanatory drawing of the reduction reaction and gasification reaction in a carbonaceous material agglomerated ore. It is a graph of the temperature transition in a furnace when arrange | positioning a carbon material and iron oxide close. It is the partially notched schematic diagram and sectional drawing of the carbonaceous material interior agglomerated mineral which concern on this invention. It is process drawing which shows an example of this invention manufacturing method. It is the photograph etc. of the microscope etc. which show the cross section of the agglomerate before and behind oxidation treatment. Firing temperature and CO in an embodiment of the carbonaceous material interior mass Naruko of the present invention, the transition of the CO ₂ is a graph showing. It is a contrast diagram of the crushing strength of a carbonaceous material agglomerated ore and sintered ore.

  Below, one Embodiment of the carbonaceous material interior agglomerate which concerns on this invention is described. FIG. 1 and FIG. 2 are the ideas that triggered the development of the carbonaceous material-rich agglomerate according to the present invention, that is, the distance between the carbonaceous material and the iron-containing raw material such as iron ore and sintered ore, and the iron-containing raw material. It is a figure explaining the relationship with the reductive reaction speed | rate. In general, the smaller the distance between the carbonaceous material such as coke and the iron-containing raw material, the faster the reaction rate. For example, when the raw material is charged from the top of the blast furnace, the iron-containing raw material such as iron ore and sintered ore and the carbonaceous material such as coke are each about 20 to 40 mm in size, as shown in FIG. As shown in (b) and (b), it is common to carry out fractional charging in layers. In this case, it is considered that if the iron-containing raw material layer such as sintered ore and the carbon material layer are thinned, the distance between the carbon material and the sintered ore becomes smaller and the reaction rate becomes faster.

  In this respect, in order to dramatically increase the reaction rate due to the contact between the two, it is considered that mixing charging of the iron-containing raw material and the carbonaceous material is effective. However, as described above, if the iron-containing raw material and the carbonaceous material are simply mixed and charged, the movement resistance of the gas, which is a heat transfer means, is too large, and the reaction rate becomes slow.

  Therefore, in recent years, techniques such as ferro-coke, carbonaceous material agglomerated minerals, and ultrafine refinement of carbonaceous materials have been considered as methods for improving the reaction rate, as shown in the conceptual diagram of FIG. Ferro-coke is a mixture of charcoal and iron ore, which is baked and hardened. Carbonaceous agglomerated ore is an iron-containing raw material filled with carbonaceous material and is ultrafine. Is a method in which carbonaceous materials are mainly refined and used.

These ideas of improving the reaction rate are based on the theory as shown in FIG. That is, FIG. 2 shows the relationship between heat exchange and reaction when the iron ore and the carbonaceous material are close to each other. On the iron ore side, Fe ₂ O ₃ and CO react to cause a reduction reaction to become Fe and CO _2, and the reaction at this time is an exothermic reaction. On the other hand, on the carbon material side, a gasification reaction (gas reforming reaction) called a Budoir reaction occurs in which CO ₂ and C react to generate CO, and this reaction is an endothermic reaction. Therefore, if the iron ore and the carbonaceous material are close to each other, the reduction reaction that is an exothermic reaction and the gasification reaction that is an endothermic reaction are repeated at a high rate. Since less heat supply is required, a decrease in the furnace temperature can be expected.

  Therefore, it can be seen that it is effective that the iron-containing raw material and the carbonaceous material are close to each other, that is, close to each other. Under such a concept, an iron-containing raw material and a carbonaceous material are mixed in advance, and a carbonaceous material agglomerated mineral in which the carbonaceous material is embedded in the iron-containing raw material is the ultimate carbonaceous material-iron. It can be in the form of a close arrangement of the contained raw materials.

In this way, in the case where the carbonaceous material and the iron-containing raw material are arranged close to each other, when the heat necessary for the gasification reaction reaches the inside of the carbonaceous material agglomerated ore, as shown in FIG. The reaction occurs in a chain from the inside of the agglomerate to the outside, such as the CO and Fe _n O _m generated in the above cause a reduction reaction, and the CO ₂ generated in the reduction reaction leads to a gasification reaction. It is considered that the internal Fe _n O _m is successively self-reduced to produce Fe (metallic iron). Therefore, in this case, since the reaction proceeds inside the agglomerate, the heat supply from the outside can be reduced, and the temperature in the furnace can be lowered accordingly.

  Based on this concept, when using a blast furnace simulator to determine the reduction rate (reduction rate) using a high-temperature kneaded product (carbon material-incorporated agglomerate) of iron-containing raw materials such as iron ore and sintered ore and carbonaceous materials As shown in FIG. 4, the carbonaceous agglomerated ore is considered to be able to lower the furnace temperature in the blast furnace as compared to the sintered ore containing no carbonaceous material. Such a decrease in the furnace temperature of the blast furnace is not only a reduction in the basic unit of air blown from charcoal materials and feathers, but also a longer life of the furnace body, and the generation amount of carbon dioxide can be relatively suppressed. There are also benefits.

  FIG. 5 is a schematic view and a cross-sectional view of a partially cut state showing an embodiment of the carbonaceous material-incorporated agglomerated mineral according to the present invention. The example shown in FIG. 5 (a) is a raw material containing metallic iron, for example, iron oxide powder 2 such as various iron-making dust and mill scale powder, and -3 mm (powder that passes 3 mm sieve mesh) in it. It is an agglomerated mineral containing coke powder 1 in a dispersed state, and at least the outer layer part of this agglomerated mineral is a low-oxidized iron oxide shell having a thickness of about 1 to 10 mm, that is, an iron oxide shell 2. This is an example of a carbonaceous material-incorporated agglomerated mineral with an overall particle size of 20 to 25 mm.

Further, in the example shown in FIG. 5 (b), the iron ore powder 3 and the granulated product in a state where the coke powder 1 having a size of -3 mm is contained in a dispersed state in the iron ore powder 3 and the outer portion thereof. A two-layer structure in which iron oxide powder made of iron dust, mill scale powder, etc. is coated with a layer thickness of about 5 to 15 mm, so that the total particle size on which the so-called iron oxide shell 2 is formed is 20 to 30 mmφ. It is an agglomerate.
In addition, as said iron ore, Preferably, inferior iron ore powders, such as a romeral iron ore, a Ukrainian iron ore, a carol lake iron ore, are formed as a granulated material about 10-2 mmphi.

In addition, FIG.5 (c) is sectional drawing of the example of the carbonaceous material agglomerated mineral of the example of FIG.5 (a), and these agglomerates including the thing of FIG.5 (b) are complete. It has a charcoal interior structure. Therefore, unlike the prior art shown in FIG. 2 (a), the reaction heat, CO, and CO ₂ do not move through the gas flowing in the reaction zone. In the present invention, FIG. 2 (b) As shown in Fig. 3, the reduction reaction and coke gasification reaction proceed simultaneously at a position close to each other in one particle (agglomerated ore), so the reaction is fast and efficient. And proceed at low temperatures.

  Fig. 5 (c) shows coke particles, iron-making dust, direct reduction furnace generated powder (RHF powder), iron oxide powder such as mill scale powder in the center of the pelletizer via a binder (starch aqueous solution 3%). Mix to obtain granulated particles having a size of about 20 to 15 mmφ. And it is sectional drawing about what was made into the granulated particle of the apparent two-layer structure of the state which coat | covered the said iron oxide powder and the carbonaceous material was further comprised in the outer side, and is a size of about 23 mmphi It is a carbonaceous material agglomerated ore.

  A characteristic matter in the carbonaceous material-containing agglomerated mineral according to the present invention is that, as will be described in detail below, the agglomerated mineral whose surface layer is composed of iron oxide shells 2 having a low degree of oxidation is treated in an atmospheric atmosphere. Oxidation treatment at medium to low temperature for 2 to 5 hours at a temperature in the middle to low temperature range (less than about 300 ° C.) forms a thin, hard, high-oxidation hard thin layer 4 (see FIG. 7) only on the outermost layer. It is in the configuration of points to be

  For this oxidation treatment, the green agglomerated ore is charged into a heating furnace such as an electric furnace, and is fired in a medium to low temperature range of 200 ° C. or more and less than 300 ° C., that is, about 2 to 5 hours in an air atmosphere. Oxidation treatment is performed, and a thin thin layer of high oxidation degree and a hard thin layer made of high oxidation degree iron oxide are formed in the outermost layer portion of the low oxidation degree iron oxide shell 2 to form a carbonaceous material agglomerated mineral for iron making. And

The carbonaceous material agglomerated ore obtained by performing such an oxidation treatment is not subjected to this treatment, and the internal coke particles remain in the center in an almost initial state. And, as shown in Table 1 and FIG. 7, the iron oxide shell 2 of this carbonaceous material agglomerated mineral is reduced in FeO and metallic iron (M.Fe), while the amount of Fe ₂ O ₃ and apparent specific gravity. Will increase. In addition, the outermost layer portion of the iron oxide shell 2 is further oxidized and densified, and thus has a cold strength comparable to that of sintered ore and a reducibility superior to that of sintered ore. become.

  In the present invention, the iron-containing raw material constituting the iron oxide shell 2 of the carbonaceous material agglomerated ore is basically iron oxide powders such as various ironmaking dusts and mill scales that are generated in large quantities at ironworks, that is, metal An iron-containing raw material is preferably used. On the other hand, as an interior carbon material located inside, coke powder having a particle size of -3 mm (muzzle size), preferably 1 mm is used.

  The iron-making dust that is one of the iron oxides has a typical metal iron content of 20 to 50 mass%, T.I. When Fe is 60 mass% or more, it can be said that it has sufficient iron content as the iron oxide shell 2 of the carbonaceous material agglomerated ore. On the other hand, the coke powder having a particle size of -3 mm is not suitable for use as a raw material for blast furnace, considering that the coke used in the blast furnace is 20 to 40 mm, and requires reprocessing. However, since it is used effectively, it is advantageous in terms of cost.

In the present invention, the reason for paying attention to iron-making dust and mill-scale iron oxide as a component of the outer shell is that they contain a large amount of metallic iron and have a low oxidation degree mainly composed of Fe, FeO, and Fe ₂ O _3. Because it is a thing. This means that this iron oxide is easily oxidized in the air in the middle and low temperature range, and this oxidation treatment converts the iron in the outer layer of the iron oxide shell 2 to iron oxide with a high degree of oxidation by the oxidation treatment. This means that it is easy to change, that is, the outermost layer portion of the iron oxide shell 2 can be hardened by oxidation to produce a thin film-like hard thin layer 4 with a higher degree of oxidation, which can be strengthened.

In the present invention, the iron oxide having a low oxidation degree is obtained by mixing an iron oxide raw material of Io <0.92 and iron ore at an oxidation degree Io calculated by the following formula, and an average oxidation degree Io (ave) is 0. It is preferable to use one less than .92. Incidentally, the following equation shows the ratio of amount of oxygen combined with Fe in the subject the iron oxide for oxygen amount when the Fe content containing becomes all Fe ₂ O _3. That is, when all the Fe content is Fe ₂ O ₃ , Io = 1.0.
Io = [(FeO% × 0.223) + (Total Fe% −Fe% made of metal)
-FeO% × 0.777) × 0.430] / (total Fe% × 0.430)

Next, the specific example of the manufacturing method of the carbonaceous material agglomerated mineral which concerns on this invention is demonstrated. In this example, as shown in FIG. 6, iron-making dust (OG dust) is pulverized to 70 μm or less (63 μm or less) as an iron oxide-containing raw material, and -3 mm powder coke and 7 mass% starch aqueous solution are added and kneaded thereto. Then, these were granulated to a size of 20 mmφ with a 400 mmφ bread type pelletizer, and then the obtained granulated powder was put into another pan pelletizer to be thickened by +3 mm to obtain an agglomerate of about 23 mmφ. The volume ratio of OG dust and coke powder was about 65:35. Then, the obtained granulated material was charged in an electric furnace and oxidized at 290 ° C. for 5 hours in an air atmosphere. The air flow rate was set to 15 1 m ³ / min, and the temperature was adjusted by the air flow rate.

As a result, the average component composition of the iron making dust, the agglomerated carbonaceous material agglomerated (raw granulated material) after granulation (before firing), the agglomerated carbonaceous material agglomerated mineral after granulation, and the hard thin layer portion An example is shown in Table 2. FIG. 8 shows the furnace temperature, sample (outer skin) temperature, CO, and CO ₂ concentration during firing (oxidation treatment). As shown in this figure, almost no CO was generated during the firing. Further, while the furnace temperature is 290 ° C., the generation of CO ₂ and the M.P. Oxidation heat generation of Fe and FeO occurred, and the sample (outer skin) temperature reached 450 ° C. As a result, it was observed that surface oxidation progressed and the outer shell portion (hard thin layer 4) was cured and densified. In addition, M. While Fe and FeO decrease, Fe ₂ O ₃ increases and free C also decreases, and it is considered that the reaction is accelerated by heat generation.

  Next, when the crushing strength was examined by pressing the calcined carbonaceous agglomerated mineral as shown in FIG. 9, the crushing strength of this carbonaceous material agglomerated ore was 90 kgf or more, and the average value was 115 kgf. It is the same level as sintered ore used for blast furnace operation. For example, if the crushing strength is low, there is a risk of pulverization by its own weight when filled in the blast furnace. When pulverized, the particle size becomes small and clogging may occur, preventing the flow of reaction gas in the furnace. Steelmaking efficiency is reduced. In this respect, if there is a crushing strength comparable to that of the sintered ore used for blast furnace operation, it will not be crushed in the blast furnace and will not cause a reduction in iron making (iron making) efficiency. Moreover, as described above, when the carbonaceous material and the iron ore are located close to each other, it becomes structurally easy to react and can react effectively at a low furnace temperature. Become.

  In addition, when using the carbonaceous material agglomerated ore according to the present invention as a part of the raw material for blast furnace charging, if the amount used is less than 10 mass% or less than 20 mass%, it can withstand transport until blast furnace charging. A degree of crushing strength is sufficient. For example, the required crushing strength may be 50 kgf or more, preferably 90 kgf, which is about the same as that of sintered ore. The coke powder may be used after pulverizing a small lump of about 3 to 15 mm.

  Thus, in the carbonaceous agglomerated ore according to the present invention, the outermost layer portion of the iron oxide shell 2 is oxidized by the oxidation treatment, and the iron oxide having the hardened thin film 4 made of high-oxidized iron oxide only on the surface layer. Since it will be in the state covered with the shell 2, a carbonaceous material agglomerated mineral with a crushing strength of 90 kgf or more is obtained. Therefore, if this is used as an agglomeration of an iron furnace such as a blast furnace, the temperature inside the blast furnace can be lowered and the efficiency of iron making can be improved, and low-cost coke or recycled dust can be used. Since it can be manufactured, the cost of the agglomerate itself is reduced.

  The iron ore used for the intermediate layer 3 is preferably a magnetic iron ore, such as romeral iron ore, carol lake iron ore, and preferably a magnetite hard ore powder having a thickness of about 5 to 10 mm on the surface of the carbon material core 1. The iron oxide shell 2 that is coated and formed on the surface of the intermediate layer 3 includes various types of iron dust such as OG dust, direct reduction furnace generated powder (RHF powder) such as a rotary hearth furnace, or mill scale. Iron oxide is preferably used. The component composition and heat quantity of each raw material powder are shown in Table 3 below.

The internal volume of 3000 m ³ grade large blast furnaces, with respect to the formulation of the normal operation using the sintered ore, carbonaceous material interior mass Naruko (table shown in FIG. 5 (a) according to the present invention a part of the (10 mass%) When the blast furnace operation replaced by the chemical component is performed in (4), the reducibility of the carbonaceous agglomerate itself increases (sintered ore 6.05% → agglomerated 95.8%). As a result, the gas utilization rate in the blast furnace is improved, the reducing agent furnace is reduced by 10 kg / t in total, and the output ratio is 2% (2.25 → 2.29 t / D) due to the influence of the decrease in the amount of Bosch gas. / M ³ ), and the effectiveness of using the agglomerated ore according to the present invention for blast furnace operation was confirmed. Table 5 below shows the operating conditions and results of the blast furnace.

In addition, the carbon material agglomerated ore used in this blast furnace operation has an effective diffusion coefficient (De) of sintered ore of 0.20 × 10 ⁻⁴ m ² / 2.0 × 10 ⁻⁴ m ² / s, which is 10 times higher than s, and the reduction powdering property (JIS RD) is 31.6% higher than that of sintered ore: 20.2%. These differences are considered to be reflected in the above blast furnace operation.

  The technology of the present invention is not limited to the exemplified raw materials for blast furnace operation, but is also effective as a raw material for other metallurgical furnaces for iron making, and the production method can be applied as a technology for producing other agglomerates. is there.

1 Coke powder 2 Iron oxide shell 3 Iron ore powder 4 Hard thin layer

Claims (6)

Iron-containing raw material formed by coating the iron oxide powder to the outside of the oxidation of iron powder or iron ore fines, a lump formed ore containing coke powder size of -3mm a dispersed state, in the mass Naruko The outer layer part of the iron-containing raw material is made of an iron oxide shell having a low oxidation degree in which the average oxidation degree Io (ave) is less than 0.92 at an oxidation degree Io calculated by the following formula: Carbonaceous agglomerate.
Record
Io = [(FeO% × 0.223) + (Total Fe% −Fe% made of metal)
-FeO% × 0.777) × 0.430] / (total Fe% × 0.430) The oxidation Tetsukara of low oxidation degree, steel carbon material interior mass Naruko according to claim 1, wherein the iron oxide powder Tona Rukoto containing at least metallic iron. Wherein the outer surface of the iron oxide shell, steel carbon material interior mass Naruko according to claim 1 or 2 characterized by having a hard thin layer made of a high oxidation degree of iron oxide. The said iron oxide shell is mainly comprised with the ironworks generation | occurrence | production dust or the mill scale, The carbon material interior agglomerated mineral for iron manufacture of any one of Claims 1-3 characterized by the above-mentioned. It strikes the manufacture of carbonaceous material interior mass Naruko containing carbonaceous material of the interior state of iron-containing raw material formed by coating the iron oxide powder to the outside of the iron oxide powder or iron ore fines, the iron oxide powder or iron ore fines and carbonaceous material Then, the mixture is granulated using a granulator, and then the outer surface of the granulated product is coated with iron oxide powder containing metal iron. In the degree of oxidation Io calculated by the following formula, the average degree of oxidation Io (ave A method for producing a carbonaceous material-containing agglomerated ore for iron making, characterized in that an iron oxide shell having a low oxidation degree of less than 0.92 is formed.
Record
Io = [(FeO% × 0.223) + (Total Fe% −Fe% made of metal)
-FeO% × 0.777) × 0.430] / (total Fe% × 0.430) After the formation of the iron oxide shell, an oxidation treatment is performed by heating in the atmosphere at a temperature of 200 ° C. or higher and lower than 300 ° C. for 0.5 to 5 hours. The method for producing a carbonaceous material-containing agglomerated mineral for iron making according to claim 5 , wherein a hard thin layer is formed.

Images