KR101444562B1 - Unfired carbon-containing agglomerate and production method therefor - Google Patents

Abstract

The non-calcined hamlet compacted light for the blast furnace has a carbon content (T. C) of 18 to 25 mass% and a porosity of 20 to 30%. A method for producing non-calcined hamsters compacted light for blast furnaces comprises the steps of: forming a compact to obtain a compact by mixing and kneading the compact and raw materials of ham, ham, and binder, and kneading the mixture; In the step of forming the molded body so that the carbon content (T. C) of the non-calcined hamlet compacted light is 18 to 25 mass% and the porosity is 20 to 30% The mixing conditions of one or two or more selected from the group consisting of the raw material particle size, the amount of fine coke, the amount of the highly purified water ore, and the amount of the binder is adjusted.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber,

The present invention relates to a non-calcined hamstick bulk light for a blast furnace, which is produced by mixing, molding, and then curing a raw material for cast iron and a raw material for hammer. In particular, the present invention relates to a non-calcined hamstick compact for a blast furnace having a carbon content (T. C) of 18 to 25 mass% and a porosity of 20 to 30%, and a method for producing the same.

The present application claims priority based on Japanese Patent Application No. 2009-192273 filed on August 21, 2009, the contents of which are incorporated herein by reference.

Conventionally, various kinds of iron and steel dust recovered from various dust collectors of steel mills and the like and a hydraulic binder of cement system are added and kneaded and molded to produce non-small intense light and briquettes of 8 to 16 mm diameter, And is used as a raw material.

As a method for producing non-calcined hamsters compacted light, there is known a method in which iron-based dust is granulated with pellets, followed by curing and curing the pellets. In the step of assembling the iron-making dust with the pellets, the particle size distribution of the dust is adjusted to an appropriate range, a binder such as burnt lime, cement and the like and 5 to 15% water are added and the mixture is assembled by a disk pelletizer, .

In order to reduce the reducing cost in the blast furnace operation, it is required to increase the carbon content (T. C) of the non-calcined hamlet compacted light in the production of such non-calcined hamstick compacted light.

For example, in Patent Document 1, a carbon-based non-burned compacted light is produced by blending a raw material for iron oxide and a carbon-based carbonaceous material, adding a binder, kneading, molding and curing. This carbon-containing, non-sintered compacted light has carbon of 80 to 120% of the theoretical amount of carbon necessary for reducing iron oxide contained in the iron oxide raw material to metal iron. Further, the binder is selected so that the crush strength at normal temperature is 7850 kN / m 2 or more, and mixing, molding, and curing are performed. Since the reduction reaction is caused by the carbon in which the iron oxide is contained in the non-calcined hamsters compacted light, the reduction ratio can be improved.

However, in the non-burning compact light of Patent Document 1, the carbon content is limited in order to secure the strength, and the effect of reducing the reduction ratio of the blast furnace is not sufficiently obtained. In order to obtain an effect of reducing the reduction cost, when a large amount of non-calcined hamstick intense light of Patent Document 1 is used in the blast furnace, the amount of heat absorbed by the dehydration reaction of the binder in the blast furnace becomes large and a low temperature heat storage band is formed. This low-temperature heat storage stand has drawbacks that promote the reduction and differentiation of the sintered ores.

In Patent Document 2, attention has been paid to the fact that the particle size and the carbon content of the carbonaceous material significantly affect the hot strength in the reduction temperature region as well as the cold strength of the non-calcined hammerite ingot, Thereby producing a non-calcined hamstick compacted light. This production method comprises a step of adding a hydraulic binder to a fine-particle carbonaceous material containing 10 mass% or more of a carbonaceous fraction and a fine iron-containing raw material containing 40 mass% or more of iron powder, , Adjusting the mixing ratio of the fine powdery carbon material so that the particle size of the whole raw material is 2 mm or less and the carbon content ratio (T. C) in the whole raw material is 15 to 25 mass%, and the median of the fine powdery carbonaceous material And a diameter of 100 to 150 mu m.

As described above, in the non-calcined hamlet compacted light for blast furnace, there is a problem of improvement of the carbon content, improvement of the reduction ratio, and improvement of the cold and hot strength (affects the fractionation rate in the furnace).

In addition, proper amount of moisture is required for the blast-furnace bulk light for blast furnace during the assembly and molding process. Further, since the cement binder exhibits strength by hydration reaction, it has a disadvantage that the number of crystals is larger than that of other raw materials, and the explosive characteristics in the blast furnace deteriorate.

On the other hand, the converter dust generated in the steelworks is collected by the non-burning gas treatment apparatus, mixed with the carbon powder as the iron raw material, and the pellets are produced. This pellet is partially reduced to the reduced iron in the rotary hearth reduction furnace and reused. The recovered converter dust contains a large amount of water and is poor in handleability and miscibility with other powders. For this reason, the converter dust is dried and used. However, when it is excessively dried, metal iron having a large specific surface area in the dust state in the converter dust reacts with air to generate heat.

Patent Document 3 discloses a recycling method of converter dust. In this method, a powder containing iron oxide and a powder containing carbon are mixed with a converter dust collected by a non-burner dust collector of a converter gas, the water content of the mixture is adjusted to 17 to 27 mass% And a step of reducing the molded body in the rotary hearth type reducing furnace. By this method, oxidation heat generation of the metal iron can be prevented and the reduction ratio can be improved.

However, this method has an effect of preventing oxidation heat generation when reducing the molded body in the rotary hearth type reduction furnace. Therefore, this method does not directly contribute to the improvement of the explosion characteristics in the blast furnace in which operating conditions such as temperature are different.

Patent Document 4 discloses a reduction method of iron oxide using a rotary hearth type reduction furnace. This method has a step of placing a molded body containing a metal oxide and carbon on a moving hearth phase and heating and heating the formed body by the heat from the combustion gas in the upper portion, Is adjusted to a specific value. Since the porosity of the molded body is adjusted to a specific value, the volume expansion caused upon reduction of the iron oxide from the hematite to the magnetite is absorbed by the pores. As a result, it is possible to achieve stable reduction because there is little division.

However, this method is also effective in preventing the formation of the molded body in the rotary hearth type reduction furnace, but the operating conditions such as the temperature and the reduction pattern do not directly contribute to prevention of the differentiation in the other blast furnace.

It is possible to improve the resistance to internal combustion such as explosion due to water vapor or reduction and differentiation, the reduction of iron oxide in non-calcined hamstock compact light, cold and hot crushing strength in blast furnace bulking for blast furnace, In order to provide the non-calcined sand blasted light for the blast furnace, it is necessary to set a detailed structure for the porosity while maintaining the carbon content of the blasted sand blasted light for blast furnace at a certain level.

However, if the porosity is large, the gasification of the carbonaceous material and the reduction rate of the iron oxide are promoted, but the cold and hot strength are accompanied by a decrease. In addition, if the porosity is too small, there is a problem that the differentiation into the furnace such as explosion by the steam or reduction and differentiation is increased.

Japanese Patent Application Laid-Open No. 2003-342646 Japanese Patent Application Laid-Open No. 2008-95177 Japanese Patent Application Laid-Open No. 2003-82418 Japanese Patent Application Laid-Open No. 2003-89813

It is an object of the present invention to provide a non-calcined hamlet compacted fiber for a blast furnace which enables efficient operation of the blast furnace by specifying the porosity and the carbon content of the hamming compacted light optimum for efficient blast furnace operation and a method for producing the same.

The inventors of the present invention have made extensive studies on the porosity and the carbon content of the non-calcined hamstick compacted fiber for blast furnace. As a result, by controlling the mixing conditions and the production conditions such that the porosity of the non-calcined hamsters compacted light is 20 to 30% and the carbon content is 18 to 25% by mass, unfired hammer intruding light capable of realizing the following characteristics can be provided .

(a) Excellent endurance for explosion or reduction by water vapor

(b) High iron oxide in the non-calcined hamsters compacted

(c) Promotion of reduction of iron ore (iron-based charge) around

The mixing conditions to be controlled include the raw material particle size, the amount of fine carbon, the amount of high-solids water ore, and the amount of cement.

The unfired hammer intruding light for a blast furnace according to one embodiment of the present invention is obtained by mixing and kneading a raw material for a steel and a raw material for a hammer and a binder and kneading the mixture to obtain a molded body and subsequently curing the molded body, , A content (T. C) of 18 to 25 mass%, and a porosity of 20 to 30%.

The method for producing non-calcined hamsters compacted light for a blast furnace according to one embodiment of the present invention is characterized by comprising a step of forming a compact to obtain a compact by mixing and kneading a raw material for ham and a raw material for ham and a binder and a binder, Curing the mixture to obtain non-calcined hamsteak compacted light so that the carbon content (T. C) of the non-calcined hamlet compacted light is 18 to 25 mass% and the porosity is 20 to 30% , One or more mixing conditions selected from the group consisting of water content of raw material, raw material particle size, amount of fine coke, blending amount of high-crystallization ore, and amount of binder is adjusted.

The non-calcined hamlet compacted light for a blast furnace according to one embodiment of the present invention has a sufficient carbon content to improve the reduction ratio of the main iron-containing blast furnace raw materials such as sintered oresite as well as non-calcined hamlet compacted light. In addition, it maintains a cold crushing strength of 100 kg / cm 2 or more as a raw material for a blast furnace, and is superior in hot strength in a reduction temperature range as compared with the conventional method.

As a result, in the blast furnace operation, it is possible to suppress the generation of non-sintered and hard-textured light such as explosion by water vapor and reduction and differentiation. In addition, the reduction ratio (coke ratio) at the time of blast furnace operation can be greatly reduced. This makes it possible to efficiently operate the furnace.

In the method for producing non-calcined hamstick compacted light for a blast furnace according to one embodiment of the present invention, since the non-sintering process is applied, energy saving and lowering of CO ₂ can be achieved compared with a sintering process. Further, the dust generated in the iron-making process can be recycled as the iron-containing raw material and the carbonaceous material by a relatively inexpensive and simple method.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph showing the relationship between the porosity and the reduction differentiation rate of non-calcined hamlet compacted light.
Fig. 2 is a graph showing the relationship between the porosity and the explosion property of the non-calcined hamstick intense light.
Fig. 3 is a diagram showing the relationship between the reduction differentiation rate of the non-calcined hamlet compacted light and the upper K value.
Fig. 4 is a graph showing the relationship between the carbon content (T. C) of the non-calcined hamlet compacted light and the explosive property.
5 is a graph showing the relationship between the explosion of non-calcined hamstring intense light and the upper K value.
FIG. 6 is a graph showing the relationship between the porosity and the cold crushing strength of non-calcined hamlet compacted light having different carbon contents. FIG.
Fig. 7 is a graph showing the relationship between the porosity of non-calcined ham denim compacts having different carbon contents and the reduction ratio of BIS.
8 is a graph showing the relationship between the porosity of the non-calcined hamlet compacted light having different carbon contents and the reduction ratio at 1000 ° C.

The non-calcined hamlet compacted light for a blast furnace of the present embodiment is produced by mixing and kneading a raw iron material, a raw material for hammer and a binder, kneading the mixture to obtain a molded body, and subsequently curing the molded body. The carbon content (T.C) is 18 to 25 mass%, and the porosity is 20 to 30%. As a result, in the blast furnace operation, it is possible to suppress the generation of non-sintered compacted gross light such as explosion due to water vapor, reduction and differentiation, and to reduce the reducing cost of the blast furnace.

In the present embodiment, the carbon content (T. C) of the non-calcined hamlet compacted light is set to 18 to 25 mass%.

If the carbon content (T. C) exceeds 25 mass% as described later in the examples, the minimum cold brittleness strength required for use in the blast furnace can not be obtained (Fig. 6). In addition, the explosive property becomes large, and stable operation can not be performed in the blast furnace of an actual furnace (Figs. 4 and 5).

When the carbon content (T. C) is less than 18 mass%, the effect of improving the reduction ratio is small (Figs. 7 and 8). As a result, the effect of improving blast furnace operation can not be obtained.

The carbon content (T. C) of the non-calcined hamsters compacted light is preferably 20 to 23 mass%, and more preferably 22 to 23 mass%.

In the present embodiment, the porosity of the non-calcined ham tossed light is made 20 to 30%.

As described later in Examples, when the porosity is less than 20%, the effect of improving the reduction ratio is limited (Figs. 7 and 8). In addition, the differentiation rate in the blast furnace is increased and sometimes exceeds the upper limit of the differentiation rate required for the raw material used in the blast furnace (Fig. 1).

When the porosity exceeds 30%, the effect of improving the reduction rate is saturated (Figs. 7 and 8). In addition, the cold crushing strength is lowered and the cold crushing strength required to be used for the blast furnace can not be minimized (Fig. 6).

The porosity of the non-calcined hamsters compacted light is preferably 23 to 27%, more preferably 24 to 26%.

The method for producing non-calcined ham to be mixed light for a blast furnace according to the present embodiment is characterized in that it comprises a step of forming a formed body by mixing and kneading a ham steel raw material and a hammer raw material and a binder and molding the kneaded product, Process. The raw material water content, the raw material particle size, the amount of fine coke, the amount of the fine cementitious ore, and the amount of the cementitious ore in the formed body are preferably controlled so that the carbon content (T.C) of the non- The compounding amount, and the amount of the binder is adjusted.

Examples of the iron-based raw material used in the present embodiment include sintered dust generated in a steelmaking process, precipitated iron dust such as sintered dust obtained by sintering containing sludge, fine iron ore such as a pellet feed having a smaller particle size than sintered powdered iron ore, And high-purity ores containing much water.

Examples of the raw material for the hammer used in the present embodiment include a blast furnace primary material, a coke dust, a fine powdered coke, and an anthracite.

In the present embodiment, the " raw water content " is also referred to as free water and means the moisture content contained in raw raw material (before curing) after molding. By increasing the water content of the raw material, the porosity can be increased. However, if the water content of the raw material is excessively high, the differentiation rate (explosive property) becomes high. Therefore, it is preferable to adjust the water content of the raw material to the range of 8 to 15%.

In the present embodiment, the raw material grain size means a weighted average value of the median diameter d50 based on the weight of the raw materials for the hammer and the raw materials for the hammer to be used. By reducing the raw material particle size, the porosity can be reduced. However, if the raw material particle size is too small, the differentiation rate (explosive property) is increased, and problems such as adhesion during production also occur. Therefore, it is preferable to adjust the weighted average value of the median diameter d50 on the basis of the weight in the range of 10 to 50 mu m.

In the present embodiment, the pulverized coke refers to a pulverized coke having a median diameter d50 of 100 mu m or less on a weight basis. The porosity can be increased by increasing the amount of pulverized coke as a raw material of the hammer. However, when the amount of the fine coke is excessively small, there arises a problem that the differentiation rate (explosive property) is increased. Therefore, it is preferable to adjust the amount of fine coke to be in the range of 10 to 30%.

In the present embodiment, the term "highly purified water ore" means an ore containing 5% or more of crystals such as Lobriver, Yandikujin, Marahamba, and the like. The porosity of the non-calcined hamsters compacted light can be increased by increasing the amount of the high-crystallization ore. However, if the amount of solid ore is excessively large, the differentiation rate (explosive property) becomes high. For this reason, it is preferable to adjust the compounding amount of the highly purified water ore to a range of 5 to 20%.

Examples of the binder to be used in the present embodiment include an aging binder consisting of a fine powder or an alkali stimulant mainly comprising blast furnace slag which is generally used, quicklime, portland cement, bentonite and the like. The amount of the binder (amount added) can be appropriately determined in consideration of other blending conditions and the like. When the amount of the binder is too small, it is difficult to sufficiently maintain the cold rolling strength of the non-sintered hammer intruding light. If the amount of the binder is too large, the amount of slag of the non-calcined hamlet compacted light increases, and the air permeability in the furnace bottom becomes unstable. As a result, an effect of stably reducing the reduction ratio can not be obtained. From the above viewpoint, a particularly preferable range of the blending amount of the binder is 5 to 19 mass%.

In the step of forming a formed body, the iron-based raw material and the raw material for hammer cut out from the raw hopper are mixed with a binder such as cement, a wet ball mill or a lightening mixer and mixed. Then, after being mixed, it is kneaded. The kneaded material of the raw material obtained by sufficiently kneading is molded into a pan pelletizer, a briquetting machine or the like. Subsequently, in the curing step of the molded article, the molded article is cured in the sunlight for several days until the strength necessary for handling is developed by the primary curing yarn. Thereafter, the molded body is cured in the sun by the secondary curing yard to sufficiently exhibit the strength by the binder such as cement. As a result, the non-calcined hamstick bulk light for blast furnace is produced. Then, it is supplied to the blast furnace and used.

In order to make the carbon content (T. C) of the non-calcined hamlet compacted light 18 to 25 mass% and the porosity 20 to 30% in the present embodiment, the production process (pellets and briquettes) Particle size, amount of fine coke, amount of highly purified water ore, amount of binder). In particular, this can be done by adjusting one or more mixing conditions selected from the group consisting of water content of raw material, raw material particle size, amount of fine coke, amount of high-crystallization ore, and amount of binder.

Generally, the pellet molding becomes porous compared to the briquetting, but either of them may be selected in accordance with the raw material conditions.

As described above, the larger the amount of the cement (the amount of the binder), the finer the non-calcined hammer intense light. The porosity of the raw material, the amount of differentiated carbon (amount of differential coke) and the amount of the cementitious ore are all increased in many cases. However, it is preferable to adjust it appropriately in consideration of the molding yield, adhesion at the time of production, and product components.

The carbon in the non-calcined hamlet compacted light of this embodiment reduces iron oxide in the non-calcined hamlet compacted light, but the excess carbon also reduces iron ore around the blast furnace. As a result, the reduction ratio can be improved (Figs. 7 and 8).

In the continuous operation of the blast furnace, the CO gas (reducing gas) rises from the lower layer to the upper layer of the blast furnace, thereby reducing the iron ore. However, when the blast furnace was operated using only coke as the reducing material, the reducing power of the reducing gas was weakened in the upper layer of the ore layer, and the reduction of the ore was not sufficiently progressed in some cases.

On the other hand, when the non-calcined hamstick compact light of the present embodiment is used, the presence of the non-calcined hamstick compact light of the present embodiment together with iron ores in the blast furnace significantly reduces the reduction efficiency in the upper layer of the ore layer have. The reduction efficiency in the upper layer of the ore layer, which is difficult to be reduced, can be greatly improved, so that the reduction efficiency in the whole blast furnace can be greatly improved. As a result, it is possible to reduce the amount of reducing material that is larger than the amount of coke of the same amount as that of carbon in the non-calcined hammer intense light of this embodiment (Fig. 7).

In addition, since the reduction efficiency in the entire blast furnace can be greatly improved, the reduction cost related to the operation of the blast furnace including pulverized coal blown from the blast port can be reduced. The reduction ratio can be reduced, so that the amount of CO ₂ generated in the steel making process can be reduced, and the environmental load can be reduced.

Example

Hereinafter, embodiments of the present invention will be described based on concrete examples. This is an embodiment, and the present invention is of course not limited thereto.

[First Embodiment]

(Preparation of non-calcined hamsters)

Mixing, mixing, molding (curing), and curing were carried out while adjusting the amount of raw material, the particle size and the water content as shown in Table 1, using a ham iron raw material, a hammer raw material and a binder to produce non- Respectively.

The porosity was measured by a water method (in accordance with JIS K2151) in which the apparent specific gravity was measured by substituting the water for the obtained non-calcined hammer intense light.

Table 1 shows the types and amounts of binders, the carbon content and the porosity of the obtained non-calcined hamsters, and the specific gravity of the obtained non-calcined hamsters, which are specifically used, the type of the crushed iron materials used, the type of crushed raw materials, .

As shown in Table 1, it was found that the non-calcined hamlet compacted light of the present embodiment can be produced by adjusting the water content of the raw material, the raw material particle size, the amount of the high-crystallization ore compounding and the amount of the binder in the numerical range described in the embodiment .

The assembly facility is not particularly limited, and may be any of those having kneading, mixing, assembling, and sieving functions as raw materials, and kneading machines and granulating machines are not particularly limited.

[Second Embodiment]

(Influence of porosity)

The effect of porosity on the differentiation of non - calcined hamsters in the furnace was investigated by preparing non - calcined hamsters with different porosity.

Crushed iron raw materials and crushed raw materials similar to those in Example 1 were pulverized, mixed with cement (binder) and kneaded to form kneaded products. The obtained molded body was cured for a predetermined period to prepare a non-sintered hammerite compact having a carbon content (T. C) of 15 and 25 mass%.

10%, 15%, 20%, 25%, 30%, and 35% by adjusting the molding pressure and the amount of cement during compression molding to a constant value, , And 40% non - calcined hamsters. Further, according to the change of the amount of the cement, the item of the raw material of the hammer was finely adjusted so that the carbon content (T. C) became constant at 15 mass% or 25 mass%.

The differentiability (reduced and differentiable) was evaluated by the following method using a reduction differentiation test (JIS M8720). 500 g of the sample was heated in N ₂ and maintained at 550 캜 for a predetermined time in a reducing gas containing 30% of CO. At this time, a sample for measurement was prepared by setting the reduction time at 550 占 폚 to 1 minute, 10 minutes, 30 minutes, and 60 minutes. A rotational impact of 900 rotations was imparted to the measurement sample by a rotation tester. (Fractionation rate (-2.8 mm%)) of the particles of 2.8 mm or less in the measurement sample after the application of the rotary impact was measured, and the reductive differentiation property was evaluated by this fractionation rate (-2.8 mm%). The results of the non-sintered ham denuded light having a carbon content (T. C) of 25% by weight are shown in Table 2 and Fig. In the present specification, the differentiation rate (-2.8 mm%) measured by applying the reduction differentiation test is also referred to as the reduced differentiation rate.

In addition, the explosion property in the blast furnace which is the weakest point of the non-burning compact light was also evaluated.

The spalling property was measured by the following method with reference to the thermal cracking test method (ISO 8371: Iron ores-Determination of description index) of iron ore. 500 g of the sample was rapidly heated in N ₂ to a maximum temperature of 700 ° C. At this time, in order to examine the influence of the heating rate (heating rate), measurement samples were prepared at heating rates of 5 ° C / min, 50 ° C / min, 500 ° C / min and 1000 ° C / min. Then, the ratio of the particles of 6.3 mm or less (the fractionation rate (-6.3 mm%)) of the measurement sample was measured, and this fractionation fraction (-6.3 mm%) was evaluated as the fracture property. The results of the non-sintered ham denuded light having a carbon content (T. C) of 15% by weight are shown in Table 3 and FIG.

Generally, the phenomenon of differentiation caused by the evaporation of the water content, the crystal water (derived from iron ore and cement) and the gas generation by gasification is called explosion. In addition, the phenomenon of differentiation that occurs due to the generation of voids or volume expansion or internal stress accompanied by reduction is called reduction differentiation. Regardless of the cause, in the present specification, the purpose is to specify the conditions for the amount of differentiation in the furnace. In the following description, there is a case where the conditions are used in unification with "differentiation".

Referring to FIG. 1, it can be seen that although the differentiation rate tends to decrease with the increase of the porosity, the effect of the reduction time is large. Reduced differentiation is caused by volume expansion and internal stress at the time of reduction of the magnetite from hematite, and is most strongly differentiated at around 550 캜. For this reason, it is known that the reductive differentiation depends on the residence time near 550 캜. That is, at the reduction of 550 DEG C or higher, the differentiation becomes rather small. From this point, the retention time at 550 캜 affects the porosity and the reductive differentiation. In the rotary hearth type reduction furnace, the heating rate is as high as 1000 deg. C / min, and the residence time at 550 deg. C is about one minute, and the reduction and differentiation is small at any porosity. On the other hand, there is a problem that the residence time at 550 DEG C in the blast furnace is 10 minutes (from the central part) to 60 minutes (peripheral part), and the reduction and differentiation rate is increased.

[Third Embodiment]

(Permissible range of reduction differentiation rate)

Generally, in order to perform stable operation in an actual furnace furnace, it is necessary to set the upper K value to 0.4 or less. From the upper limit value of the upper K value, the permissible range of the reduction differentiation rate of the non-calcined hamsters compacted was examined.

The blending amount of the raw material was adjusted so that the carbon content (T. C) became 25 mass%, and the non-calcined hammerite compact having different porosity was produced in the same manner as in the second embodiment.

The fractionation rate (-2.8 mm%) was measured in the same manner as in the method for evaluating reductive degradability of the second example.

Further, in order to evaluate the air permeability of the shaft at the time of using the blast furnace, the upper K value was measured by the following method. Short - term tests were carried out using various non - calcined hamsters with different porosity (ie differentiation rate) in a blast furnace of 4500 m 3 capacity. 10 wt% of non-calcined hamsters compacted light of the entire iron-based charge was mixed and charged into the ore layer. The operational specifications of the blast furnace were as follows: the reduction ratio 480 kg / tp, and the weight ratio of ore and coke was 5.0. From the measured value of the pressure probe installed on the wall of the furnace, the aeration resistance value (upper K value) at the upper portion of the shaft was calculated. The obtained results are shown in Table 4 and Fig.

Fig. 3 shows the relation between the differentiation rate of the non-calcined hamstring bundle and the upper K value. As described above, in order to perform stable operation in the blast furnace of an actual furnace, it is necessary to set the upper K value to 0.4 or less. From the relationship between the differentiation rate (reduced differentiation rate) of the non-calcined hamartocarpal light shown in FIG. 3 and the upper K value, it is found that in the non-calcined hamlet compacted light having a carbon content of 25% by weight, the differentiation rate (reduced differentiation rate) exceeds 40% , The upper K value increases to more than 0.4, and it is found that stable operation becomes difficult. Therefore, it is important to lower the differentiation rate (reduced differentiation rate) to not more than 40% in the non-calcined hamsters compacted light having a carbon content of 25% by weight.

Referring to FIG. 1, at a porosity of 20% or more, the differentiation rate is relatively low. On the other hand, when the porosity is less than 20% with 20% as the boundary, the reduction fraction is rapidly increasing. In particular, when the reduction time is 30 minutes or more, this tendency is remarkable. On the other hand, when the porosity is 20% or more, the differentiation rate (reduced differentiation rate) can be suppressed to 40% or less even if the reducing time is 60 minutes. If the porosity is increased, it is considered that the internal stress caused by the volume expansion of the non-calcined hamstick intense light is dispersed by the pores and the reduction differentiation is suppressed. Therefore, in order to solve the problem of the differentiation (reduction and differentiation) of the non-calcined ham denitric light for blast furnace, it is understood that the reduction time should be made as short as possible and the porosity should be 20% or more.

Referring to Fig. 2, although the explosion (explosive property) tends to decrease with the increase of the porosity, the influence of the temperature raising rate is remarkable. This is considered to be because the higher the rate of temperature rise is, the less the balance between the amount of steam generated and the amount of discharged water in the sample per hour is, and the internal pressure is increased. In the rotary hearth type reduction furnace, the heating rate is as high as 1000 캜 / min, and the non-calcined hamstick compact light is liable to be heated. On the other hand, the heating rate of the blast furnace is 5 ° C / min (peripheral portion) to 50 ° C / min (center portion). Therefore, referring to Fig. 2, it can be considered that when the non-calcined ham denaturated light having a carbon content of 15% by mass is used in a blast furnace, the problem of differentiation (explosive property) does not occur.

[Fourth Embodiment]

(Influence of carbon content)

Next, the influence of the carbon content (T. C) of the non-calcined hamsters compacted light was examined.

The effect of carbon content (T. C) on differentiation (explosive properties) was investigated by preparing non - calcined hamsters with different carbon contents (T. C) and porosity.

The carbon content (T. C) was 15 mass%, 18 mass%, and 25 mass% in the same manner as in the method of Example 2 except that the mixing ratio of the raw material for cast iron and the raw material for hammer, the molding pressure at the time of compression molding and the amount of cement were adjusted. %, 30% by mass, and porosity of 10%, 20%, 30% and 40%, respectively.

Except that the heating rate (heating rate) was 50 캜 / minute, the fractionation rate (-6.3 mm%) was measured in the same manner as in the evaluation method of the explosion property of the second embodiment to evaluate the explosion property. The heating rate of 50 캜 / min is the most stringent heating condition in the blast furnace. The obtained results are shown in Table 5 and Fig.

As shown in FIG. 4, it can be seen that the increase in the carbon content (T. C) in the non-calcined hamlet compacted light leads to an increase in the differentiation due to the explosion. It is considered that this is because the substrate strength of the non-calcined hamstick tonnage light is lowered with the increase of the carbon content (T. C), and the proof against the internally generated gas pressure is lowered. For this reason, when the carbon content (T. C) is 18 mass% or more as in the present embodiment, it is necessary to consider the explosion property.

[Fifth Embodiment]

(Permissible range of explosion)

As described above, in order to perform stable operation in the blast furnace of an actual furnace, it is necessary to set the upper K value to 0.4 or less. From the upper limit value of the upper K value, the permissible range of the explosion property of the non-calcined hamstick intense light was examined.

(T. C) of 20% by mass and a porosity of various values were measured in the same manner as in the method of Example 2 except that the mixing ratio of the raw material for the steel and the raw material for the crushing, the molding pressure at the time of compression molding and the amount of cement were adjusted. Firing compacted light was produced.

Except that the heating rate (heating rate) was 50 캜 / minute, the fractionation rate (-6.3 mm%) was measured in the same manner as in the evaluation method of the explosion property of the second embodiment to evaluate the explosion property.

The upper K value was measured in the same manner as in Example 3, using non-calcined hamsters compacted light in an amount of 10 mass% with respect to the total iron-based charge. The obtained results are shown in Table 6 and Fig.

Fig. 5 shows the relationship between the explosion and the upper K value of non-calcined hamstick intense light having a carbon content (T. C) of 20 mass%. From FIG. 5, the influence of the explosive property of the non-calcined hamstick intense light on the air permeability of the blast furnace was investigated when the non-calcined hamstick intense light in the blast furnace was used in an amount of 10 mass% with respect to the total iron-based charge.

From the relation between the explosion of the non-calcined hamstring tonnage light and the upper K value at the time of using the blast furnace shown in Fig. 5, when the explosive property exceeds 30%, the upper K value rises to more than 0.4 and the stable operation becomes difficult have. Therefore, it is important to reduce the explosive property to 30% or less.

In the second and third embodiments, from FIG. 2, it can be seen that the larger the porosity, the smaller the explosive property. From Fig. 1, it was also found that the porosity was required to be 20% or more. Referring to FIG. 4, in the non-calcined hammerite compact having a porosity of 20% or more, it is understood that the explosive property becomes 30% or less when the carbon content (T.C) is 25 mass% or less. As a result, it is necessary to set the carbon content (T. C) to 25 mass% or less.

[Sixth Embodiment]

(Cold crush strength, 1000 占 폚 reduction ratio and reducing agent ratio in BIS furnace)

The carbon content (T. C) was 15 mass%, 18 mass%, and 25 mass% in the same manner as in the method of Example 2 except that the mixing ratio of the raw material for cast iron and the raw material for hammer, the molding pressure at the time of compression molding and the amount of cement were adjusted. 10%, 15%, 20%, 25%, 30%, 35% and 40% of porosity.

The charging material for the blast furnace is required to have sufficient strength to withstand handling such as transportation and sizing until charging to the blast furnace. As an index of such strength, in the present embodiment, the cold crushing strength of the non-calcined hamlet compacted light was measured.

The cold crushing strength was measured in accordance with JIS M8718 " Iron / Pellet Crush Strength Test Method " as follows. One sample was subjected to a compressive load at a specified pressing half speed to measure the load value when the sample was broken, and the average value of 100 samples was evaluated as the cold crush strength. The obtained results are shown in Table 7 and FIG.

Fig. 6 shows the relationship between the porosity of the non-calcined hamlet compacted light and the cold crushing strength.

Referring to FIG. 6, it can be seen that, in the range of the carbon content (18 mass%, 25 mass%) of the present embodiment, the cold crushing strength is determined by the difference of the porosity almost without depending on the carbon content. It is difficult to maintain 100 kg / cm < 2 >, which is the lower limit of the cold crushing strength required for use in the blast furnace, even if the porosity is 30% or more. Therefore, from the viewpoint of cold crush strength, the porosity should be 30% or less.

Further, in the non-sintered laminated hamsters having a carbon content of 26% by mass (exceeding the upper limit value of 25% by mass in the range specified in this embodiment), the porosity is 20% or more and the cold crushing strength is 100 kg / The lower limit of the use of blast furnaces). Therefore, the carbon content should be 25 mass% or less. If the amount of the coke to be blended is excessively large, the amount of the binder penetrating into the open pores in the coke increases. Therefore, when the carbon content exceeds 25 mass%, it is considered that it is difficult to efficiently manifest the strength by the binder.

Next, according to the characteristic evaluation method (see BIS: Steel and Steel, 72 (1986) 1529) when using the blast furnace compacted light obtained, the reduction ratio and the reduction ratio at 1000 캜 were measured by BIS as follows .

10 wt% of unburned hammerite intense light of the entire iron-based charge was homogeneously mixed with the ore layer and charged into the BIS furnace so as to form a layer with the coke layer. The BIS is a test apparatus for simulating the countercurrent reaction of the blast furnace shaft portion, and is composed of a reaction tube charged with a sintered light and a coke in a layer form, and a vertically movable type electric furnace. The loading amount was adjusted so that the weight ratio of iron oxide to carbon was 5.0. The amount of the Bosch gas and the gas of the composition corresponding to the operation of the reduction coal cost of 480 kg / tp and the pulverized coal blowing rate of 150 kg / tp was supplied to the BIS furnace to perform ore reduction.

The shaft efficiency to BIS and heat storage temperature were measured and the thermal mass balance was calculated from these measurements. The reduction ratio of the thermal mass resin to the BIS was determined.

After the reduction of the ore by the BIS furnace was completed, the sintered light at the position of 1000 占 폚 and the non-calcined hamsters compacted light were collected. Then, chemical analysis of the collected sintered ores and non-sintered sand blasted light was carried out, and the reduction ratio at 1000 ° C was obtained from the analytical values. Here, the 1000 占 폚 reduction rate means the reduction characteristics of the entire iron-based charge including the charged non-calcined hamsters compacted light.

The obtained results are shown in Tables 8 and 9, and Figs. 7 and 8.

Figs. 7 and 8 show reduction ratios and reduction rates of 1000 deg. C in the BIS furnace, respectively, when the unbaked Hamming compacted amount of 10 wt% of the total iron-based charge was uniformly mixed with the ore layer. Referring to FIGS. 7 and 8, it can be seen that the higher the carbon content, the higher the 1000 ° C reduction ratio and the reduction reduction ratio. When the carbon content is 15%, the reduction rate of 1000 占 폚 is remarkably lowered, and the efficiency of blast furnace operation is lowered. For this reason, the lower limit value of the carbon content (T.C) is set to 18%.

In addition, the porosity is increased and the reduction ratio at 1000 ° C is improved. Even when the carbon content (T. C) was 18% by mass, the reduction ratio reached 75% and the reduction ratio reached 470 kg / tp or less when the porosity was 20%. However, when the porosity is less than 20%, the effect of reducing the reduction ratio by improving the reduction ratio of 1000 占 폚 is limited, and it becomes almost the same as the condition without the non-calcined hamsters compact light. On the other hand, when the porosity exceeds 30%, it is found that the effect of improving the reduction ratio at 1000 캜 and reducing the reduction ratio is saturated. Therefore, it can be seen that the porosity of 20% or more and 30% or less of the carbon content (T. C) is preferably set to 18% by mass or 25% by mass.

From the above results, in order to most effectively exhibit the effects of the differentiation rate, explosive property, cold-pressing strength, reduction ratio and reducing material cost in the blast furnace operation, it is preferable that a carbon content (T.C) of 18 to 25 mass% and a porosity of 20 to 30 % Of non-calcined hamsters compacted light can be used.

In addition, free water is introduced into the hydrate in the compacted sand by the hydration reaction of the cement during curing in the process of mixing, kneading, molding and curing. Therefore, when the raw material is subjected to the production process, the entire blending amount of the raw material is slightly changed, but the amount of change is small and it can be considered that most of the raw material is not changed. As a result, for example, the blending amount of the binder becomes substantially equal to the binder content in the produced non-calcined hammer intruding light. The amount of the other components in the manufacturing process is almost the same as that in the non-calcined ham denatural light.

The non-calcined hamlet compacted light according to one embodiment of the present invention has a sufficient carbon content to improve the reduction ratio of not only non-calcined hamsters but also sintered rare-earth iron-containing raw materials when used in a blast furnace. Further, it maintains a cold crushing strength of not less than 100 kg / cm 2 which is required as a raw material for a blast furnace, and is superior in the hot strength in the reduction temperature range as compared with the prior art. As a result, the reduction ratio (coke ratio) at the time of blast furnace operation can be greatly reduced.

In addition, in the method for producing non-calcined hamsters compacted light according to one embodiment of the present invention, energy saving and lowering of CO ₂ are possible as compared with the firing process. In addition, the dust generated in the iron-making process can be recycled as iron-containing raw materials and carbonaceous materials by a relatively inexpensive and simple method.

Therefore, one form of the present invention can be suitably applied to the technical field related to the hammer intense light used in the blast furnace.

Claims (2)

delete Mixing and kneading a mixing raw material composed of 63 to 75% by mass of the iron-based raw material containing the highly purified water ore, 5 to 19% by mass of the binder, and the finely divided coke having the grain size of 100 탆 or less as the remainder, A forming step of forming a molded body by molding water,
Subsequently curing the molded body to obtain unbaked hammerized compacted light having a cold crushing strength of 100 kg / cm 2 or more,
The water content of the raw material is adjusted to 8 to 15 mass% in the step of forming the molded article so that the carbon content (T. C) of the non-calcined hamsteak compacted light is 18 to 25 mass% and the porosity is 20 to 30% , Adjusting the raw material particle size to 10 to 50 탆, adjusting the amount of fine coke in the blended raw material to 10 to 30 mass%, adjusting the amount of the highly purified water ore in the blending raw material to 5 to 20 mass% Wherein the amount of the binder in the blast furnace is adjusted to 5 to 19 mass%.

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