JP6326074B2 - Carbon material interior ore and method for producing the same - Google Patents

Description

  The present invention relates to a carbonaceous interior ore used as an ironmaking raw material in a blast furnace and a method for producing the same.

  In recent years, carbon material interior ores formed by mixing and granulating a carbon material and an iron oxide-containing raw material have been proposed for the purpose of reducing the reducing material ratio in blast furnace operation.

  Carbonaceous interior ore used as a raw material for blast furnaces is required to have excellent reducibility in addition to strength and reduced powderability in a low temperature range.

  As a method for producing an unfired carbonaceous interior ore excellent in crushing strength and reducibility of this kind, as shown in Patent Document 1, an iron-containing raw material containing a high crystal water ore having a particle size of 10 μm or more and 50 μm or less Are mixed and molded with fine coke having a particle size of 100 μm or less and a hydraulic binder such as cement, the carbon content of the carbonaceous material interior ore is 18% by mass or more and 25% by mass or less, and the porosity is 20% or more. A method of setting it to 30% or less is known.

In addition, as a method for producing a carbonaceous interior ore excellent in cold crush strength and reducibility, as shown in Patent Document 2, the specific surface area by the BET method is 0.6 m ² / g or more and 10 m ² / g or less. There is known a method in which a mixture of an iron-containing raw material and a softening and melting carbon material is molded at a temperature of 250 ° C. or higher and 550 ° C. or lower.

International Publication No. 2011/021560 JP 2007-77484 A

  However, in the method of the above-mentioned patent document 1, it takes time and expense for the primary curing after the molding, the secondary curing, and the subsequent drying treatment, and there is a problem that it cannot be efficiently manufactured.

  Moreover, in the method of the above-mentioned patent document 2, since it is necessary to heat a raw material to 250-550 degreeC and to shape | mold hot, an energy loss is large compared with the case of non-baking, and facilities also become complicated, There may be problems that cannot be efficiently produced.

  This invention is made | formed in view of such a point, and it aims at providing the carbonaceous material interior ore which can be manufactured efficiently, and its manufacturing method.

The carbon material-containing ore according to claim 1 is a carbon material-containing ore formed using an iron oxide-containing raw material, a carbon material, and an organic binder, and the iron oxide-containing raw material includes iron ore and iron making. Iron oxide containing at least one of the iron oxide-containing dust recovered from the dust collector in the station, where the carbon content (% by mass) in the iron oxide raw material and the total mass of the iron oxide-containing raw material and carbonaceous material are 1. When the amount of carbon derived from the iron oxide-containing raw material, which is a value multiplied by the blending ratio of the containing raw material, is X, and the total carbon mass (mass%) in the carbonaceous material and the total mass of the iron oxide-containing raw material and the carbonaceous material are 1. When the carbon amount derived from the carbonaceous material, which is a value obtained by multiplying the carbonaceous material blending ratio by Y, is satisfied, the relationship expressed by 3.5X + Y ≧ 25 is satisfied, and the relationship expressed by 0.2X + Y ≦ 20 is satisfied To do.

  The carbonaceous interior ore according to claim 2 is the carbonaceous interior ore according to claim 1, wherein the iron oxide-containing raw material has a carbon content of 5 mass% or more and less than 30 mass%.

  The carbon material interior ore according to claim 3 is the carbon material interior ore according to claim 1 or 2, wherein the carbon material has a carbon content of 70% by mass or more.

The method for producing a carbonaceous material-containing ore according to claim 4 includes adding an organic binder to the powdered iron oxide-containing raw material and the powdered carbonaceous material, adjusting the moisture, mixing and granulating, and non-firing. A method for producing a carbonaceous interior ore to be produced, wherein the iron oxide-containing raw material is at least one of iron ore and dust containing iron oxide recovered from a dust collector in the ironworks, and carbon in the iron oxide raw material the content (mass%) and carbon content derived from the iron oxide-containing material is a value obtained by multiplying the mixing ratio of the iron oxide-containing material in the case of the one total mass of iron oxide-containing material and carbonaceous material and X, charcoal In the case where the carbon content derived from the carbon material, which is a value obtained by multiplying the carbon content (% by mass) in the material with the blending ratio of the carbon material when the total mass of the iron oxide-containing raw material and the carbon material is 1, is defined as Y. 3.5X + Y> 25 is satisfied And it is used for adjusting the raw material so as to satisfy the relationship shown by 0.2X + Y <20.

  The method for producing a carbon material interior ore according to claim 5 is the method for producing a carbon material interior ore according to claim 4, wherein the iron oxide-containing raw material has a carbon content of 5 mass% or more and less than 30 mass%. There is something.

  The method for producing a carbon material interior ore according to claim 6 is the method for producing a carbon material interior ore according to claim 4 or 5, wherein the carbon material has a carbon content of 70% by mass or more. .

  According to the present invention, when the amount of carbon derived from the iron oxide-containing raw material is X and the amount of carbon derived from the carbonaceous material is Y, the relationship represented by 3.5X + Y ≧ 25 is satisfied, and 0.2X + Y ≦ 20 In order to satisfy the relationship shown in, the reducibility can be improved and the crushing strength as a blast furnace raw material can be ensured simply by adjusting the types and blends of the iron oxide-containing raw material and carbonaceous material, so that it can be efficiently produced. .

It is a graph which shows the conditions of the reduction | restoration test at the time of measuring the reduction rate of a carbon material interior ore. It is a graph which shows the relationship between carbon material interior ore carbon content and a reduction rate. It is a graph which shows the relationship between the carbon content and crushing strength of a carbon material interior ore. It is a graph which shows the relationship between the value shown by 3.5X + Y of a carbon material interior ore, and a reduction rate. It is a graph which shows the relationship between the value shown by 0.2X + Y of carbon material interior ore, and crushing strength.

  Hereinafter, the configuration of an embodiment of the present invention will be described in detail.

  Carbonaceous interior ore is prepared by mixing powdered iron oxide-containing raw material and powdered carbonaceous material at a predetermined ratio, adding an organic binder, adding water, adjusting the water appropriately, mixing and Manufactured granulated.

Iron oxide-containing material is one containing iron oxide, iron ore, and, Dust recovered from dust collector ironworks is used. Not only these ingredients is used alone, but it may also be formulated more at a predetermined ratio.

  The amount of carbon contained in the iron oxide-containing raw material is preferably 5% by mass or more in order to improve the reducibility of the carbonaceous interior ore. On the other hand, when the amount of carbon contained in the iron oxide-containing raw material is 30% by mass or more, the crushing strength of the carbonaceous material-containing ore may be reduced. Therefore, the amount of carbon contained in the iron oxide-containing raw material is preferably 5% by mass or more and less than 30% by mass.

  As the carbon material, for example, powdered coke, general coal, anthracite, coke dust, or the like is used. These raw materials are not only used alone, but a plurality of types may be blended at a predetermined ratio. Moreover, it is not limited to these raw materials, You may use another carbonaceous material.

  The amount of carbon contained in the carbon material is preferably 70% by mass or more in order to ensure the reducibility of the carbon material interior ore.

  As the organic binder, for example, pulp waste liquid, molasses, various polymers, starch, carboxymethyl cellulose, and the like are appropriately used. In addition to these being used alone, a plurality of types may be blended at a predetermined ratio. Moreover, it is not limited to these organic binders, You may use another organic binder.

  Furthermore, as a raw material, in addition to an organic binder, an inorganic binder such as quick lime or bennite may be added within a range in which the amount of slag in the raw material does not increase.

  The amount of organic binder added can be determined as appropriate, but if the ratio of the organic binder in all raw materials is less than 1% in terms of solid content, there is a possibility that sufficient crushing strength as a raw material for blast furnaces may not be secured, and in terms of solid content If it exceeds 10%, the strength improvement effect is saturated and the material cost increases. Therefore, the addition amount of the organic binder is preferably 1% or more and 10% or less in terms of solid content.

  When the raw material is granulated, for example, a compression granulation method in which a pillow type briquette or an almond type briquette is manufactured with a briquette machine having a pair of molding rolls, and a rolling granulation method in which the raw material is formed into a spherical shape with a pan pelletizer. Although it is performed appropriately, the method is not limited to these methods, and granulation may be performed by other methods.

  The non-fired carbonaceous material-containing ore immediately after molding needs to have a certain strength in order to withstand transportation to the blast furnace and pulverization during charging of the blast furnace. For this reason, the raw carbon material interior ore after molding is subjected to a drying process to improve the strength. Such a drying treatment is preferably performed, for example, with hot air of 100 ° C. or more and 300 ° C. or less so that the moisture content of the short material interior ore is 3% or less.

  Here, the carbon content greatly influences the reducibility of the carbonaceous interior ore, and the greater the carbon content, the better the reducibility and the greater the reduction effect of the blast furnace reductant ratio. On the other hand, when the amount of carbon in the carbonaceous material interior ore increases, the crushing strength decreases. Therefore, it is conventionally manufactured with a carbon amount that satisfies the crushing strength and reducibility required as a carbonaceous interior ore.

  However, the carbon in the carbon material interior ore is not only carbon contained in the carbon material, but also derived from iron oxide-containing raw materials. The effect on the properties such as reducibility was examined.

  In order to confirm the influence on the reducibility of the carbonaceous interior ore due to the difference in the carbon content and the blending amount of the iron oxide-containing raw material, the carbon content and the carbon content from each carbon source were changed. An interior ore was manufactured and the crushing strength and the reduction rate were measured.

  First, four types of iron oxide-containing raw materials were blended at the ratio shown in Table 1.

  Moreover, the powdery coke which is a carbon material, and general charcoal were mix | blended in the ratio shown in Table 2.

  After adding the two types of organic binders shown in Table 3 to the iron oxide-containing raw materials and charcoal blended in various proportions, kneading while adding moisture, compression molding using a briquette machine, Produced. The carbonaceous interior ore (raw briquette) is an almond type of 25 mm × 18 mm × 10 mm.

  And after drying raw briquette at 105 degreeC for 2 hours or more, while crushing strength was measured, it used for the reduction | restoration test. The crushing strength was measured according to JIS M8718. Moreover, the reduction test was performed with the temperature and gas history shown in FIG. 1, and the reduction rate was measured from the components after the test.

  In FIG. 2, the carbonaceous inner ore in the case of using iron ore A containing no carbon as the iron oxide-containing raw material and in the case of using in-house dust containing 8% by mass of carbon as the iron oxide-containing raw material. The relationship between carbon content and a reduction rate is shown.

  When iron ore A that does not contain carbon is used as the iron oxide-containing raw material, the reduction rate increases as the carbon content increases. In contrast, when in-house dust containing carbon is used as the iron oxide-containing raw material, the reduction rate is 100% regardless of the carbon content, and the reduction rate is higher than when iron ore A is used. became. In addition, when compared with the same carbon content, the reduction rate was higher when in-house dust containing carbon was used as the iron oxide-containing raw material.

  That is, it can be seen that the carbon contained in the iron oxide-containing raw material has a higher effect of improving the reducibility of the carbonaceous material interior ore.

  In FIG. 3, the carbonaceous inner ore in the case of using iron ore A containing no carbon as the iron oxide-containing raw material and in the case of using in-house dust containing 8% by mass of carbon as the iron oxide-containing raw material. The relationship between carbon content and crushing strength is shown.

  When the iron ore A containing no carbon is used as the iron oxide-containing raw material and when the in-house dust containing carbon is used, when the carbon content exceeds a predetermined amount, the crushing strength rapidly decreases.

  In addition, the amount of carbon in which the crushing strength rapidly decreases is different between the case of using iron ore A and the case of using in-house dust, and the case of using in-house dust causes a decrease in strength at a higher carbon amount.

  In other words, the carbon contained in the carbon material has less adverse effect on reducing the crushing strength of the carbon material interior ore than the carbon contained in the iron oxide-containing raw material.

  As described above, since the influence on the crushing strength and the reducibility differs between the carbon derived from the iron oxide-containing raw material and the carbon derived from the carbonaceous material, in order to produce a carbonaceous interior ore excellent in crushing strength and reducibility Therefore, it is necessary to optimize the mixing ratio of raw materials in consideration of the difference in influence due to the carbon source.

  Then, the relationship between crushing strength and reducibility, the carbon amount (X) derived from the iron oxide-containing raw material, and the carbon amount (Y) derived from the carbonaceous material was confirmed.

Incidentally, a carbon content derived from the iron oxide-containing material X is a case where the total weight of iron oxide-containing material and carbonaceous material in the amount of C (mass%) and carbonaceous material in interior ore iron oxide-containing material and 1 a value obtained by multiplying the mixing ratio of the iron oxide-containing material, a carbon content derived from carbonaceous material Y is, C content in the carbonaceous material (mass%) and iron oxide-containing material in the carbonaceous material furnished ore and carbonaceous material It is a value obtained by multiplying the blending ratio of the carbonaceous materials when the total mass of 1 is 1 .

  As shown in FIG. 4, the reduction rate has a correlation with the value indicated by 3.5X + Y, and the crushing strength has a correlation with the value indicated by 0.2X + Y as shown in FIG.

  Specifically, the reduction rate of the carbonaceous interior ore increases with an increase in the value indicated by 3.5X + Y regardless of the type of raw material containing iron oxide, and the reduction rate is 25 or more when the value indicated by 3.5X + Y It reaches about 100%.

  On the other hand, when the value shown by 0.2X + Y exceeds 20, the crushing strength is greatly reduced in any iron oxide-containing raw material.

  From the above results, the amount of carbon derived from the iron oxide-containing raw material (X) and the amount of carbon derived from the carbonaceous material (Y) satisfy the relationship represented by 3.5X + Y ≧ 25 and are represented by 0.2X + Y ≦ 20. By adjusting the blending of raw materials so as to satisfy the relationship, it is possible to produce a carbonaceous interior ore that is excellent in crushing strength and reducibility.

  The reason why carbon contained in the iron oxide-containing raw material has a larger reducibility improvement effect is considered to be because the distance between the iron oxide and the carbonaceous material is short and the reducibility improvement effect by the carbonaceous material is large. . The reason why carbon contained in the iron oxide-containing raw material is likely to reduce the crushing strength is considered to be because the particle size of the carbonaceous material is smaller than that of the iron oxide-containing raw material.

  Next, effects and the like of the one embodiment will be described.

  According to the above embodiment, when the amount of carbon derived from the iron oxide-containing raw material is X and the amount of carbon derived from the carbonaceous material is Y, the relationship expressed by 3.5X + Y ≧ 25 is satisfied, and The reducibility can be improved and the crushing strength as a blast furnace raw material can be secured only by adjusting the types and blends of the iron oxide-containing raw material and the carbonaceous material so as to satisfy the relationship represented by 2X + Y ≦ 20. Therefore, it is possible to efficiently produce a carbonaceous interior ore excellent in crushing strength and reducibility without performing post-treatment and firing after molding.

  Moreover, by using the iron oxide containing raw material whose carbon amount is 5 mass% or more and less than 30 mass%, it is easy to improve reducibility and to ensure crushing strength.

  Furthermore, it is easy to ensure reducibility by using a carbon material having a carbon content of 70% by mass or more.

  Hereinafter, examples and comparative examples will be described.

  First, the raw materials having the composition shown in Table 4 were kneaded while adding water, and compression molded using a briquette machine to form an almond-type raw briquette of 25 mm × 18 mm × 10 mm.

  In addition, after the raw briquette was dried at 105 ° C. for 2 hours or longer, the crushing strength was measured according to JIS M 8718 and subjected to a reduction test.

  Table 5 shows the carbon amount (X) derived from the iron oxide-containing raw material in each example and each comparative example, the carbon amount derived from the carbonaceous material (Y), various relational expressions of these X and Y, and the respective experimental results. Show.

  No. 5 is an example in which the value indicated by 3.5X + Y is 25 or more and the value indicated by 0.2X + Y is 20 or less. 1 to No. No. 6 had a crushing strength of 0.7 kN or more, a sufficient crushing strength as a raw material for a blast furnace could be secured, the reduction rate was 100%, and the reducibility was good.

  On the other hand, No. which is a comparative example. 7 had a value of 0.2X + Y of 20 or less and high crushing strength, but the value of 3.5X + Y was less than 25, so the reduction rate was as low as 90.3% and the reducibility was inferior. .

  Moreover, No. which is a comparative example. 8 and no. 9 has a value of 3.5X + Y of 25 or more and good reducibility, but the value of 0.2X + Y exceeds 20, so that the crushing strength is lower than 0.7 kN, which is sufficient as a raw material for blast furnace. The strength could not be secured.

Claims (6)

A carbonaceous material interior ore formed using an iron oxide-containing raw material, a carbonaceous material, and an organic binder,
The iron oxide-containing raw material is at least one of iron ore and dust containing iron oxide recovered from a dust collector in the ironworks,
The amount of carbon derived from the iron oxide-containing raw material, which is a value obtained by multiplying the carbon content (mass%) in the iron oxide raw material by the blending ratio of the iron oxide-containing raw material when the total mass of the iron oxide-containing raw material and the carbonaceous material is 1. Is the carbon content (mass%) in the carbon material, and the carbon content derived from the carbon material, which is a value obtained by multiplying the carbon material content (mass%) and the mixing ratio of the carbon material when the total mass of the iron oxide-containing raw material and the carbon material is 1. In the case of Y,
A carbonaceous interior ore characterized by satisfying the relationship represented by 3.5X + Y ≧ 25 and satisfying the relationship represented by 0.2X + Y ≦ 20. The carbonaceous material-containing ore according to claim 1, wherein the iron oxide-containing raw material has a carbon content of 5% by mass or more and less than 30% by mass. The carbonaceous material interior ore according to claim 1 or 2, wherein the carbonaceous material has a carbon content of 70 mass% or more. A method for producing a carbonaceous material-containing ore that adds an organic binder to a powdered iron oxide-containing raw material and powdered carbonaceous material, adjusts the moisture, mixes and granulates, and produces it without firing.
The iron oxide-containing raw material is at least one of iron ore and dust containing iron oxide recovered from a dust collector in the ironworks,
The amount of carbon derived from the iron oxide-containing raw material, which is a value obtained by multiplying the carbon content (mass%) in the iron oxide raw material by the blending ratio of the iron oxide-containing raw material when the total mass of the iron oxide-containing raw material and the carbonaceous material is 1. Is the carbon content (mass%) in the carbon material, and the carbon content derived from the carbon material, which is a value obtained by multiplying the carbon material content (mass%) and the mixing ratio of the carbon material when the total mass of the iron oxide-containing raw material and the carbon material is 1. In the case of Y,
The raw material is adjusted so as to satisfy the relationship represented by 3.5X + Y> 25 and the relationship represented by 0.2X + Y <20. The method for producing a carbonaceous material-containing ore according to claim 4, wherein the iron oxide-containing raw material has a carbon content of 5% by mass or more and less than 30% by mass. Carbon material content is 70 mass% or more, The manufacturing method of the carbon material interior ore of Claim 4 or 5.

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