JP2008156661A - Method for producing coke for blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing coke for a blast furnace capable of increasing the ratio of coal having high expansion pressure used without raising the expansion pressure of a coke oven. <P>SOLUTION: The method for producing the coke for the blast furnace is a method for adjusting a weighted average value of the total expansion ratio of non or slightly caking coal in blended coal comprising coal having a high expansion pressure, non or slightly caking coal and caking coal charged into the coke oven, to ≤30%. This can greatly reduce an expansion pressure of the blended coal upon carbonization of coal in a carbonization chamber of the coke oven. Further, the ratio of grains of the coal having high expansion pressure of ≤0.7 mm is set to ≥45 mass%. A binder in an amount of ≥5 mass% based on the coal having a high expansion pressure is added, kneaded beforehand, then mixed with the residual blended coal and carbonized in the coke oven. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing coke for a blast furnace, and more particularly to a method for producing coke for a blast furnace for reducing damage to the coke oven and improving coke extrusion.

  In the process of producing coke by carbonizing coal in the coke oven, the coal expands when heated and exerts pressure on the coke oven wall. This pressure is generally called expansion pressure. Yes. If this expansion pressure is high, the resistance (extrusion resistance) when coke is discharged from the carbonization chamber to the outside of the furnace (at the time of extrusion) increases, and an excessive load acts on the furnace wall, which may damage the furnace wall. is there. Furthermore, if the expansion pressure becomes abnormally high, the furnace wall of the coke oven may be directly damaged and become inoperable. For this reason, it is an important issue to manage the expansion pressure below the allowable limit value for coke oven damage in the operation of the coke oven. In particular, coke ovens have been aging in recent years, and the allowable limit value has been lowered due to the decrease in furnace strength. In addition, the introduction of coal pretreatment technology such as the humidity-controlling coal method has recently introduced coal into the coke oven carbonization chamber. As the bulk density rises and the expansion pressure tends to increase, expansion pressure management has become an increasingly important issue for extending the life of coke ovens.

  In patent document 1, the arithmetic mean value of the maximum expansion pressure of each brand coal constituting the blended coal, the blending rate of non-slightly caking coal, the total expansion rate of the blended coal only of caking coal, and the caking material. Coke that calculates the blended coal expansion pressure from the addition rate, and adjusts the coal brand, blending ratio, and binder addition rate so that the calculated blended coal expansion pressure is less than or equal to the predetermined allowable limit pressure of the coke oven. A method of operating the furnace has been proposed.

JP 2001-214171 A

Coal charged into the coke oven can be roughly classified into three types: high expansion pressure coal, non-slightly caking coal, and caking coal. High expansion pressure coal is coal whose maximum expansion pressure is 15 kPa or more when dry-distilled at a furnace density of 1250 ° C. with a charging density of 0.85 t / m ³ . Non-slightly caking coal has an average maximum reflectance (average maximum reflectance of vitrinite measured by the method described in JIS M8816 coal fine structure component and reflectance measurement method, hereinafter abbreviated as Ro) of 0.8. The following coal or coal (the maximum fluidity measured by the fluidity test method (Gieseller Plastometer method) of JIS M8801, hereinafter abbreviated as MF) is 10 ddpm or less. The caking coal refers to a raw material coal for producing coke that does not correspond to a high expansion pressure coal or a non-slightly caking coal.

  High expansion pressure coal as shown above is mainly caking coal with low volatile content, and the strength of coke produced from high expansion pressure coal is usually high, while high expansion pressure coal is When coke oven charging coal is added, the coke oven expansion pressure increases, and as a result, the coke manufacturers are known to have a large negative impact on the coke oven, resulting in sluggish demand and lower market prices. For this reason, if the usage rate of the high expansion pressure coal can be further improved from the current level without increasing the expansion pressure of the coke oven, effective use of resources can be achieved.

  An object of this invention is to provide the manufacturing method of the coke for blast furnaces which can increase the usage rate of a high expansion pressure coal, without raising the expansion pressure of a coke oven.

That is, the gist of the present invention is as follows.
(1) Of the blended coal composed of high expansion pressure coal, non-slightly caking coal, and caking coal charged in the coke oven, the weighted average value of the total expansion rate of non-slightly caking coal is 30% A method for producing coke for blast furnace, which is adjusted to be as follows.
(2) The ratio of particles of 0.7 mm or less of the high expansion pressure coal among the high expansion pressure coal, non-slightly caking coal, and blended coal composed of caking coal charged in the coke oven is 45 masses. %, And a weighted average value of the total expansion coefficient of the non-slightly caking coal is adjusted to be 30% or less.
(3) Among the high-expansion pressure coal, non-slightly caking coal, and blended coal composed of caking coal charged into the coke oven, 5 mass% or more of caking material is used with respect to the high-expansion pressure coal. The method for producing coke for blast furnace according to the above (1) or (2), wherein after adding and kneading in advance, it is mixed with the remaining blended coal and dry-distilled in a coke oven.
(4) The above (2), wherein the high expansion pressure coal is classified at a classification point of 0.7 mm using a classifier, and only the high expansion pressure coal on the sieve is pulverized using a pulverizer. Or the manufacturing method of the coke for blast furnaces as described in (3).

In the present invention, high expansion pressure coal refers to coal having a maximum expansion pressure of 15 kPa or more when dry-distilled at a furnace density of 1250 ° C. with a charging density of 0.85 t / m ³ . Non-coking coal is a coal having an average maximum reflectance (average maximum reflectance of vitrinite measured by the method described in JIS M8816 coal microstructure and reflectance measuring method) of 0.8 or less, or flow This refers to coal having a degree (maximum fluidity measured by the fluidity test method (Gieseller Plastometer method) of JIS M8801) of 10 ddpm or less.

  According to the present invention, the usable amount of high expansion pressure coal, which can be used only in a small amount in the related art, without increasing the expansion pressure of the coke oven is dramatically increased. Thereby, the raw material selection range is expanded, and effective use of resources can be achieved.

In the present invention, firstly, high expansion pressure coal, which is composed of high expansion pressure coal, non-slightly caking coal, and caking coal charged into a coke oven, is refined, that is, high expansion pressure. The ratio of particles of 0.7 mm or less of charcoal is 45% by mass or more. Thereby, when dry-distilling coal in a coke oven carbonization chamber, an expansion pressure can be reduced greatly. Here, the high expansion pressure coal is coal having a maximum expansion pressure of 15 kPa or more when dry-distilled at a furnace temperature of 1250 ° C. with a charging density of 0.85 t / m ³ .

  In FIG. 1, the ratio of −0.7 mm of high expansion pressure coal is shown on the horizontal axis, and the expansion pressure of the blended coal in the coke oven is shown on the vertical axis. It can be seen that the higher the -0.7 mm ratio of the high expansion pressure coal, that is, the finer the high expansion pressure coal, the lower the expansion pressure of the blended coal in the coke oven. Here, in FIG. 1, the blending ratios of high expansion pressure coal, caking coal, and non-slightly caking coal are 20% by mass, 40% by mass, and 40% by mass, respectively. The pulverized particle size is -3 mm 80% by mass. Moreover, the caking additive is not added. The high expansion pressure coal is strong caking coal with Ro 1.56%, MF200 ddpm, and maximum expansion pressure 100 kPa. The caking coal is Ro1.22% and MF900ddpm. The non-slightly caking coal is Ro 0.78%, MF100ddpm, total expansion rate (the sum of contraction rate and expansion rate measured by JIS M8801 expansion test method (dilatometer method), Total Dilatation, hereinafter referred to as TD) Is 40%.

  The reason why the expansion pressure decreases due to the refinement of the high expansion pressure coal is considered as follows. That is, coal softens and melts in the carbonization process and then resolidifies to become coke. The cause of the expansion pressure is the pressure of the pyrolysis gas of the coal trapped in the softened and melted coal bed. High expansion pressure coal has a feature that its viscosity when softened and melted is very high. For this reason, in the case of dry distillation of coal containing high expansion pressure coal, the generated gas cannot easily escape from the softened and melted layer with high viscosity, and is trapped inside the coal layer and the coke layer is removed by the gas pressure increase. Then, it acts on the coke oven wall as an expansion pressure. On the other hand, it is considered that when the particle size of the high expansion pressure coal is reduced as in the present invention, the gas easily escapes to the outside of the coal particles, and the pressure in the particles decreases.

  In this invention, the expansion pressure at the time of dry distillation of coal in a coke oven carbonization chamber is made by making the ratio of particles of 0.7 mm or less of high expansion pressure coal out of coal charged into the coke oven to 45 mass% or more. Can be greatly reduced.

  Usually, the pulverized particle size of the coal charged into the coke oven is usually controlled by the weight percentage under the sieve of 3 mm, and the average pulverized particle size is about 80% by mass at −3 mm. To increase the proportion of particles of 0.7 mm or less of the high expansion pressure coal specified in the present invention to 45% by mass or more only by pulverization using a pulverizer usually used for pulverizing raw coal for coke production Further, the high expansion pressure coal may be pulverized and finely divided so that the proportion of particles of 3 mm or less is 85 mass% or more.

  The effect of reducing the expansion pressure of the blended coal increases as the high expansion pressure coal is strongly pulverized and refined using a pulverizer. However, as the high expansion pressure coal is pulverized with a pulverizer, the amount of finely pulverized coal increases, and problems such as handling and carryover such as dust generation during transportation and charging into the coke oven occur. It is preferable to control the particle size of the pulverized coal so that the particle size of 0.3 mm or less where the above problem becomes apparent is reduced.

  On the other hand, by controlling the particle size distribution of the high expansion pressure coal by using a special pulverizer or combining it with a sieve, the particle size is controlled to the lower limit value of the particle size that does not adversely affect the operation of the coke oven such as dusting. Is preferred.

  According to the study by the inventors, in the range of relatively fine particle size of 0.7 mm or less in the particle size distribution after pulverizing the high expansion pressure coal, the effect on the expansion pressure reduction effect of the blended coal does not depend on the particle size. I found the same thing. That is, according to the examination results of the inventors, the expansion pressure of the blended coal is the same between the high expansion pressure coal with −0.7 mm being 100 mass% and the high expansion pressure coal with −0.3 mm being 100 mass%. It was. The reason is considered to be that when the size of the coal particles of the high expansion pressure coal is reduced, the influence of the particle size on the diffusion of gas from the inside of the particles to the outside is reduced. On the other hand, since the particle size of the fine powder that adversely affects the operation of the coke oven is 0.3 mm or less as described above, the fine powder of -0.3 mm is reduced as much as possible after pulverizing the high expansion pressure coal, and 0.3-0 It is preferable to increase the particle size range of .7 mm.

  As a specific method for reducing the fine powder of -0.3 mm and increasing the particle size range of 0.3-0.7 mm after pulverizing the high expansion pressure coal, for example, as shown in FIG. In addition, the high expansion pressure coal 2 is classified using a classifier 1 at a classification point of 0.7 mm, and only the high expansion pressure coal 2 on the sieve is pulverized using the pulverizer 3. It is possible to suppress overpulverization of fine powder of 0.7 mm or less in the raw coal of No. 2 and to make particles of 0.7 mm or less of the high expansion pressure coal 2 45 mass% or more and to reduce fine powder of -0.3 mm. It becomes possible.

  For example, when the inventors have made particles of 0.7 mm or less of high expansion pressure coal 45% by mass or more using such a pulverizer and classifier, the mass ratio of particles of 0.3 mm or less is 21% by mass. Compared with the case of pulverizing without using a classifier (the mass ratio of particles of 0.3 mm or less is 28 mass%), the mass ratio of particles of 0.3 mm or less can be greatly reduced. It was.

  On the other hand, for caking coal, since the expansion pressure is originally low, the effect of suppressing expansion pressure due to fine granulation is small. Rather, due to fine granulation, (1) the generation of dust when handling coal increases, The bulk density when charging into the coke oven decreases, the coke production per coke oven decreases, and (3) dust generation dust (carry over) increases when charging coal into the coke oven. However, carbon adhering to the coke oven furnace wall increases and the coke extrudability deteriorates, or the riser pipe for discharging the coke oven gas is blocked, resulting in a reduction in processing efficiency due to carry over in the coke oven gas processing system. Adverse effects such as Therefore, it is preferable that the above-described strong pulverization for suppressing the expansion pressure is only high expansion pressure coal.

  In addition, for non-slightly caking coal, the inventors have confirmed that the expansion pressure of the blended coal is reduced by pulverization and fine granulation. In addition to the strong pulverization, the expansion pressure of the blended coal can be further reduced by strongly pulverizing the non-slightly caking coal. According to the inventor's study, for example, when the ratio of -0.7 mm of high expansion pressure coal is 45% by mass in the experimental condition of FIG. 1 described above, the expansion pressure of the blended coal can be reduced to 8 kPa. In addition, the non-slightly caking coal in the blended coal is strongly pulverized and refined to increase the -0.7 mm ratio of the non-slightly caking coal by 3% by mass (the ratio of -3 mm is normal pulverization). In the case of an increase of about 4% by mass), the expansion pressure of the blended coal further decreases by 1 kPa, and the ratio of −0.7 mm is increased by 6% by mass (the ratio of −3 mm is 7 for normal grinding). (Corresponding to an increase of about mass%), the expansion pressure of the blended coal further decreased by 2 kPa.

  Secondly, among the blended coals composed of high expansion pressure coal, non-slightly caking coal, and caking coal charged in the coke oven, the present invention includes the coal type and blending ratio of the non-slightly caking coal. It adjusts and it adjusts so that the weighted average value of the total expansion coefficient of a non-slightly caking coal may be 30 mass% or less. As a result, when the coal is carbonized in the coke oven carbonization chamber, the expansion pressure of the blended coal can be greatly reduced.

  It has already been shown in Patent Document 1 that the expansion pressure of blended coal can be suppressed by increasing the blending ratio of non-slightly caking coal. However, it has not been known so far. As shown in FIG. 3, the inventors of the present invention, among non-slightly caking coals, have a total expansion rate (total dilatation measured by JIS M8801 expansion test method (dilatometer method), Total Dilatation). It has been found that the effect of reducing the expansion pressure of the blended coal is greater as the type of non-slightly caking coal is smaller.

  In FIG. 3, the blending ratios of high expansion pressure coal, caking coal, and non-caking coal are 22.5 mass%, 42.5 mass%, and 35 mass%, respectively. High expansion pressure coal is Ro 1.44%, MF400ddpm, strong caking coal with maximum expansion pressure 40kPa, caking coal is Ro 1.18%, MF170ddpm. Moreover, the grinding | pulverization particle size of the whole coal blend is -3 mm 80 mass%, and the mass ratio of -0.7 mm of high expansion pressure coal is 40 mass% among the coal blends. Moreover, the caking additive is not added.

  Although it is easy to think that it is natural that the expansion pressure is low when the total expansion coefficient is low, there is generally no correlation between the total expansion coefficient and the expansion pressure as shown in FIG. This is a numerical value indicating how much the softened and melted coal expands under free expansion conditions, whereas the expansion pressure is the heat of the coal trapped in the softened and melted coal bed. This is because the pressure is caused by the cracked gas. In other words, no matter how high the total expansion rate of coal, if the gas can easily escape from the coal layer softened and melted under restraint conditions, the expansion pressure will be low. For this reason, conventionally, there has been no idea of using coal with a low total expansion rate, particularly non-slightly caking coal of a coal type with a low total expansion rate, in order to reduce the expansion pressure of the blended coal.

  The reason why the expansion pressure of the blended coal is lowered by blending non-slightly caking coal of a coal type having a small total expansion rate is considered as follows. That is, the non-slightly caking coal 4 has a lower degree of coalification and a lower resolidification temperature than the high expansion pressure coal 5, so that the high expansion pressure coal 5 having a high degree of coalification has already been resolidified when softened and melted. As shown in FIG. 5 (a), it is presumed that the pyrolysis gas 6 generated from the high expansion pressure coal 5 is not easily held in the softened molten coal layer.

  Further, the reason why the expansion pressure of the blended coal decreases as the non-slightly caking coal 4b of the coal type having a lower total expansion rate is estimated as follows. That is, when the non-slightly caking coal 4b of the coal type having a low total expansion rate is used as compared with the non-slightly caking coal 4a of the coal type having a high overall expansion rate, the non-slightly caking coals are sufficiently separated from each other. As shown in FIG. 5 (b), since the passage through which the pyrolysis gas 6 generated from the high expansion pressure coal 5 escapes further increases, the gas easily escapes to the outside, and the gas pressure in the softened molten coal layer does not adhere. Is estimated to have decreased.

  In the present invention, when blending non-slightly caking coal of a plurality of coal types in the blended coal, the total expansion rate of simple non-slightly caking coal of each coal type is measured, and a value obtained by weighted average of these values. The total expansion rate of the non-slightly caking coal can be obtained. And if the total expansion coefficient weighted average of non-slightly caking coal is made into 30% or less, it is possible to reduce the expansion pressure of blended coal below an allowable value. The lower the weighted average of the total expansion ratio of the non-slightly caking coal blended in the blended coal, the greater the effect of reducing the expansion pressure of the blended coal. . In order to reduce the influence of the decrease in coke strength accompanying the excessive decrease in the overall expansion rate of non-slightly caking coal and maintain the required coke strength, the lower limit value of the total expansion rate is more preferably 5%. preferable.

  Thirdly, the present invention relates to the above-mentioned first that finely expands the high expansion pressure coal among the high expansion pressure coal, non-slightly caking coal, and blended coal composed of the caking coal charged in the coke oven. And the second invention for adjusting the total expansion rate of the non-slightly caking coal by selecting the coal type of the non-slightly caking coal. Thereby, it is possible to further reduce the expansion pressure of the blended coal by the synergistic action of the first and second inventions described above.

  4thly this invention is 5 mass% or more with respect to high expansion pressure coal among the high expansion pressure coal, the coal mixture comprised by the high expansion pressure coal, non-slightly caking coal, and caking coal charged to a coke oven. After the kneading material is kneaded in advance, it is mixed with the remaining blended coal and subjected to dry distillation in a coke oven. As a result, the expansion pressure can be greatly reduced when the coal is carbonized in the coke oven carbonization chamber.

  Although it is shown in Patent Document 1 that the expansion pressure can be suppressed by adding the binder to the blended coal, as shown in FIG. 6, the addition ratio of the binder per paired coal is the same. Under the condition of (1.5% by mass), a binder such as tar or pitch is selectively added to the high expansion pressure coal among the blended coals (addition ratio to the high expansion pressure coal: 10% by mass) and kneaded. Then, the expansion pressure of the blended coal can be further reduced by mixing with the remaining non-slightly caking coal and caking coal.

  In FIG. 6, the blending ratios of high expansion pressure coal, caking coal, and non-caking coal are 15% by mass, 45% by mass, and 40% by mass, respectively. High expansion pressure coal is Ro 1.59%, MF120ddpm, maximum expansion pressure 60kPa strong caking coal, caking coal is Ro1.22%, MF900ddpm, non-slightly caking coal is Ro0.76%, MF50ddpm, TD40%. Moreover, the grinding | pulverization particle size of the whole coal blend is -3 mm 80 mass%, and the mass ratio of -0.7 mm of high expansion pressure coal is 40 mass% among the coal blends.

  The reason why the expansion pressure is reduced by selectively adding the caking additive to the high expansion pressure coal is that the addition of the caking agent reduces the viscosity of the coal layer where the high expansion pressure coal is softened and melted, and the gas escapes. It is thought that this is because the high expansion pressure coal is considered to be particularly effective in reducing the viscosity as compared with other caking coal and non-caking coal.

  Examples of the caking additive include coal tar, asphalt, and bitumen such as pitch obtained by distilling or increasing the weight of tar or asphalt, but is not limited thereto.

  Regarding the addition rate of the binder when selectively adding the binder to the high expansion pressure coal, in order to obtain a sufficient expansion pressure reduction effect, addition of 5% by mass or more with respect to the high expansion pressure coal is required. It is necessary, and more desirably 8% by mass or more.

  As for the upper limit value of the above-mentioned binder addition rate, the greater the addition rate, the greater the effect of suppressing the expansion pressure, but when a large amount of binder is added and kneaded, it is difficult to handle coal due to adhesion during transportation, etc. Therefore, the upper limit of the addition rate is preferably 18% by mass, more preferably 14% by mass.

  Among the blended coals, the fourth invention in which 5% by mass or more of a binder is selectively added to the high expansion pressure coal with respect to the high expansion pressure coal is the first invention in which the high expansion pressure coal is refined. The expansion pressure can be further reduced by using both of the above and the second invention that limits the total expansion rate of non-slightly caking coal, or both.

After the blended coal shown in Table 1 was adjusted to a moisture content of 3%, it was charged into a movable wall type test coke oven (furnace width 400 mm, furnace length 1000 mm, furnace height 1000 mm) with a charging density of 0.85 t / m ^3. And then carbonized at a furnace temperature of 1250 ° C. for 18 hours. At this time, the expansion pressure acting on the movable wall during the dry distillation process was measured. The mixing ratio of the high expansion pressure coal and the non-slightly caking coal is as shown in Table 1, and the mixing ratio of the high expansion pressure coal is 15% by mass (Examples 1 to 17, Comparative Example 1) and 25% by mass (implementation). Two types of Examples 18 to 34 and Comparative Example 2) were used. The remainder other than high expansion pressure coal and non-slightly caking coal is blended with ordinary caking coal.

  The high expansion pressure coal used here is strongly caking coal with Ro 1.56%, MF 200 ddpm, and maximum expansion pressure 100 kPa. The caking coal is Ro1.22% and MF900ddpm. The non-slightly caking coal A has a total expansion rate of 5%, the non-slightly caking coal B has a total expansion rate of 15%, the non-slightly caking coal C has a total expansion rate of 25%, and the non-slightly caking coal D has a total expansion rate of 35%. % Coal.

  Here, the allowable range of the expansion pressure when carbonizing coal blend in a coke oven is 8 kPa or less.

  Examples 1 to 4 and 18 to 21 are examples in which pulverization and strengthening of high expansion pressure coal is performed, and the maximum expansion pressure is 8 kPa or less, which satisfies the target.

  Examples 5 to 8 and 22 to 25 are examples when selecting a coal type of non-slightly caking coal, and the maximum expansion pressure is 8 kPa or less, which satisfies the target.

  Examples 9 to 12 and 26 to 29 are examples in which high expansion pressure coal is pulverized and strengthened, and coal type selection of non-slightly caking coal is performed, and the maximum expansion pressure is 8 kPa or less, and the target Is satisfied.

  Examples 13, 14, 30, and 31 are examples where a caking additive is selectively added to high expansion pressure coal, and the maximum expansion pressure is 8 kPa or less, which satisfies the target.

  Examples 15 and 32 are examples in which crushing and strengthening of high expansion pressure coal was performed and a caking additive was selectively added to high expansion pressure coal, and the maximum expansion pressure was 8 kPa or less, which satisfied the target. is doing.

  Examples 16 and 33 are examples in which coal type selection of non-slightly caking coal was carried out and caking material was selectively added to high expansion pressure coal, and the maximum expansion pressure was 8 kPa or less. Is satisfied.

  Examples 17 and 34 are examples in which high expansion pressure coal is pulverized and strengthened, non-slightly caking coal type is selected, and a caking agent is selectively added to high expansion pressure coal. The maximum expansion pressure is 8 kPa or less, which satisfies the target.

  On the other hand, Comparative Examples 1 and 2 are comparative examples in which neither pulverization strengthening of high expansion pressure coal, coal type selection of non-slightly caking coal, or caking material selection addition to high expansion pressure coal was performed, The maximum expansion pressure exceeded 8 kPa, and the target could not be achieved.

  From the above, it can be seen that by implementing the present invention, the expansion pressure can be suppressed to an allowable value or less under a condition where the high expansion pressure coal ratio is high.

It is a figure which shows the relationship between the particle size of high expansion pressure coal, and an expansion pressure. It is a figure which shows embodiment for reducing and grind | pulverizing the fine powder of high expansion pressure coal. It is a figure which shows the relationship between the total expansion rate of a non-slightly caking coal, and an expansion pressure. It is a figure which shows the relationship between a total expansion rate and expansion pressure. It is a schematic diagram which shows the expansion pressure suppression effect by a non-slightly caking coal, (a) is a non-slightly caking coal with a low total expansion rate, when (b) is a non-slightly caking coal with a high total expansion rate. Is used. It is a figure which shows the relationship between a caking additive addition rate and an expansion pressure.

Explanation of symbols

1 Classifier 2 High expansion pressure coal 3 Pulverizer 4a Non-slightly caking coal with high total expansion rate 4b Non-slightly caking coal with low overall expansion rate 5 High expansion pressure coal 6 Pyrolysis gas

Claims (4)

  Of the blended coal composed of high expansion pressure coal, non-slightly caking coal, and caking coal charged in the coke oven, the weighted average value of the total expansion rate of the non-slightly caking coal is 30% or less. A method for producing coke for blast furnace, which is adjusted as described above.   Of the blended coal composed of high expansion pressure coal, non-slightly caking coal, and caking coal charged in the coke oven, the proportion of particles of 0.7 mm or less of the high expansion pressure coal is 45% by mass or more. And the manufacturing method of the coke for blast furnaces characterized by adjusting so that the weighted average value of the total expansion coefficient of a non-slightly caking coal may be 30% or less.   Of the blended coal composed of high expansion pressure coal, non-slightly caking coal, and caking coal charged in the coke oven, 5% by mass or more of caking material is added to the high expansion pressure coal in advance. The method for producing coke for a blast furnace according to claim 1, wherein after kneading, the mixture is mixed with the remaining blended coal and dry-distilled in a coke oven.   The high expansion pressure coal is classified at a classification point of 0.7 mm using a classifier, and only the high expansion pressure coal on the sieve is pulverized using a pulverizer. Of blast furnace coke.

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