JP5247193B2 - Coke manufacturing method and pig iron manufacturing method - Google Patents

Description

  The present invention relates to a coke production technique using modified raw coal, and a pig iron production technique using the technique.

  As coking coal for producing blast furnace coke, blended coal of high grade strongly caking coal and low grade weak caking coal or non-caking coal is used. It is because the strength of coke obtained is improved by blending high-grade strong caking coal, and further, gas permeability during operation in a blast furnace can be secured. However, high-grade strong caking coal is gradually being depleted, and its raw material costs are rising, and there is a technology for reforming low-grade weakly caking coal and non-caking coal that exist in large quantities. It has been studied (Patent Documents 1 to 4, Non-Patent Document 1).

  For example, in Patent Documents 1 and 2, a coal reformed product obtained by mixing pulverized coal and a solvent and heating in an atmosphere of hydrogen under normal pressure or increased pressure is treated to 60 to 25%. It has been disclosed that a caking filler having a volatile content of 90% or more and having a caking strength index of 90% or more is blended with weakly caking coal or non-caking coal. In Patent Documents 3 and 4, brown coal or the like is mixed with a hydrogen-donating solvent to form a slurry, which is hydrogenated and liquefied using a catalyst at high temperature and high pressure, and finally refined SRC (solvent refined coal ) Is extracted and used as coking coal.

In addition, the present inventors can improve the strength of the obtained coke, and, if the coke strength is comparable, use the amount of high-grade coal such as strongly caking coal or high-degree coal. As a technique to reduce, for example, a technique of carbonizing raw coal containing coal substantially not containing ash is proposed (for example, Patent Documents 5 and 6).
Japanese Patent Laid-Open No. 51-107301 JP 51-107302 A JP-A-7-53965 JP-A-8-269459 JP 2007-023190 A JP 2007-246684 A Toru Nishi et al., “About using SRC as a raw material for coke”, Proceedings of the 72nd Coke Special Meeting, p. 46-p. 49 (1982)

  This invention is made | formed in view of the said situation, and it aims at providing the technique which improves the intensity | strength of the obtained coke.

  In the technology for carbonizing raw coal containing coal substantially free of ash that has been proposed by the present inventors, coal having a particle diameter of less than 15 mm was used as coal substantially free of ash. . However, as a result of continuous studies by the present inventors, it has been found that the strength of coke obtained can be further improved by controlling the particle diameter of coal that does not substantially contain ash, thereby completing the present invention. It came.

  The coke production method of the present invention that has solved the above problems includes coal having a carbon content (daf) of 85% or more and 91% or less, and a carbon content (daf). ) Is a coal that contains 60% or more and less than 85% of coal and coal substantially containing no ash and having a particle diameter of less than 1 mm. Coal is generally classified into anthracite, strong caking coal, caking coal, weak caking coal, non-caking coal, lignite, peat, etc., but the definition is not necessarily clear. A part of caking coal may be called adhesive charcoal. Therefore, in the present invention, anthracite coal, strong caking coal, caking coal, weak caking coal, non-caking coal, etc. are classified by carbon content (daf), and anthracite coal is carbon content ( d.af) More than 91% coal, strong caking coal with a carbon content (daf) of 85% or more and 91% or less, caking coal with carbon content (d.a.f.) F.) Is 83% or more and less than 85% coal, weakly caking coal is carbon content (daf) is 80% or more and less than 83% coal, non-caking coal is carbon content (d A.f.) is 78% or more and less than 80% coal, lignite is carbon content (daf) is 70% or more and less than 78% coal, and peat is carbon content (d Af)) less than 70% coal. Here, the carbon content (daf = dry ash free) is the carbon content (% by mass) of organic matter (C, H, O, S, N) excluding moisture and ash content of coal. It can be measured according to JIS M8819. Hereinafter, coal having a carbon content (daf) of 85% or more and 91% or less is simply referred to as “strongly caking coal”, and the carbon content (daf) is 60% or more and 85%. Less than coal may be simply called "non-caking coal etc.".

  In the present invention, as the raw coal, coal having a carbon content (daf) of 85% to 91% and coal having a carbon content (daf) of 60% to less than 85%. And if it is coal which does not contain ash content substantially and contains coal with a particle diameter of less than 1 mm, the coke intensity | strength obtained will improve. The coal containing substantially no ash is more preferably having a particle size of less than 0.5 mm, and more preferably having a particle size of less than 0.15 mm. It is preferable that the content rate of the coal which does not contain the said ash content in the said raw material coal is 15 mass% or less. Coal containing substantially no ash is obtained by pulverizing a soluble component obtained by extraction using an organic solvent from coal having a carbon content (daf) of 60% or more and less than 95%. It is preferable to use it. The organic solvent is, for example, an organic solvent containing a bicyclic aromatic compound as a main component.

  The present invention includes a pig iron manufacturing method characterized by using coke obtained by the above-described coke manufacturing method of the present invention.

  According to the present invention, as a substitute for a part of strongly caking coal that is a raw material for producing coke, a low caking coal or non-caking coal having a carbon content (daf) of 60% or more and less than 95% is used. Coal modified from coal or the like can be used, and can cope with the problem of depletion of strong caking coal and rising raw material costs. Moreover, the obtained coke also has the characteristic that it is excellent in intensity | strength, and can be utilized suitably for manufacture of pig iron in a blast furnace.

  The method for producing coke according to the present invention includes a coal having a carbon content (daf) of 85% to 91% and a carbon content (daf) of 60% to less than 85%. It is characterized by dry-distilling raw coal containing coal and coal substantially containing no ash and having a particle diameter of less than 1 mm.

  First, coal that does not substantially contain ash used in the present invention (hereinafter sometimes referred to as “ashless coal”) and has a particle diameter of less than 1 mm will be described.

  The ashless coal may be coal that does not substantially contain ash, but may contain a small amount of ash. In such a case, the ash content is preferably 5,000 ppm or less, and more preferably 2,000 ppm or less. In addition, ash is a residual inorganic substance when coal is ashed at 815 ° C. and is made of, for example, silicic acid, alumina, iron oxide, lime, magnesia, alkali metal, or the like.

  The ashless coal used in the present invention preferably has a particle diameter of less than 1 mm, preferably less than 0.5 mm, and more preferably less than 0.15 mm. Here, the ashless coal having a particle size of less than 1 mm, less than 0.5 mm, and less than 0.15 mm means ashless coal that passes through a 1 mm, 0.5 mm, and 0.15 mm sieve, respectively. By using ashless coal having a small particle size, the strength of the obtained coke is improved. Moreover, it is also a preferable aspect that the particle diameter of the ashless coal is less than 0.006 mm. Here, the particle diameter of less than 0.006 mm means that the particle size distribution is measured with a laser diffractometer and the maximum particle diameter is less than 0.006 mm.

  The ashless coal having a particle size of less than 1 mm preferably has a 50% particle size of 600 μm or less, more preferably 500 μm or less, based on a mass-based cumulative distribution. The ashless coal having a particle diameter of less than 0.5 mm preferably has a 50% particle diameter of a mass-based cumulative distribution of 300 μm or less, more preferably 250 μm or less. The ashless coal having a particle size of less than 0.15 mm preferably has a 50% particle size of a volume-based cumulative distribution of 20 μm or less, more preferably 15 μm or less. The ashless coal having a particle size of less than 0.006 mm preferably has a 50% particle size of 5 μm or less, more preferably 2 μm or less, in a volume-based cumulative distribution. The 50% particle size of ashless coal having a particle size of less than 1 mm and less than 0.5 mm can be determined by a dry sieving method, and the particle size of ashless coal having a particle size of less than 0.15 mm and less than 0.006 mm. The 50% particle size can be determined by a laser diffraction / scattering method. In the present invention, by controlling not only the particle size by sieving but also the 50% particle size, the strength of the obtained coke tends to be improved.

  In the present invention, the ashless coal is obtained by extracting with an organic solvent from coal having a carbon content (daf) of 60% or more and less than 95% (more preferably 60% or more and less than 85%). It is preferable to use a soluble component. This is because if non-caking coal or the like is used as a starting material, it is not affected by the problem of exhausting strong caking coal. In particular, in the present invention, the coal extracted with the organic solvent is a weakly caking coal, a non-caking coal having a carbon content (daf) of 70% or more and less than 83%, and lignite, or these It is a preferred embodiment to use a mixture of

  Specifically, the ashless coal is obtained by mixing coal with an organic solvent having a carbon content (daf) of 60% or more and less than 95% (more preferably 60% or more and less than 85%). A slurry is prepared, the slurry is heated and aged to extract a soluble component in the organic solvent, and the obtained slurry is separated into a supernatant and a concentrated solution in which solid phase components are concentrated, and the supernatant The ashless coal can be obtained by filtering and removing the organic solvent by evaporation. FIG. 1 is an explanatory view illustrating an apparatus and a process for producing ashless coal. In the tank 1, coal having a carbon content (daf) of 60% or more and less than 95% is mixed with an organic solvent to produce a slurry. The obtained slurry is supplied to an extraction tank 4 where an extraction process is performed by a pump 2. At that time, the slurry is heated to a predetermined temperature by the preheater 3. In the extraction tank 4, after the soluble component is extracted into the organic solvent while stirring the slurry using the stirrer 10, the obtained slurry is supplied to the gravity settling tank 5. In the gravity settling tank 5, gravity settling is performed to settle the solid phase component (arrow 11), and the slurry is separated into a supernatant liquid and a liquid in which the solid phase component is concentrated. The obtained supernatant is supplied to the filter unit 8, and the solid phase component concentrate settled in the gravity sedimentation tank 5 is collected in the solid phase component concentrate receiver 6. The supernatant liquid is filtered by the filter member 7 of the filter unit 8, and the obtained filtrate is recovered in a supernatant liquid receiver 9 that recovers the supernatant liquid. Next, ashless coal can be obtained by evaporating and removing the organic solvent from the collected supernatant. As a method for evaporating and removing the organic solvent from the supernatant, a general drying method such as a spray drying method, a distillation method, or a vacuum drying method can be applied.

  The coal concentration in the slurry is suitably 10 to 35% by mass. The conditions for heating and aging the slurry to extract soluble components in the organic solvent include, for example, the slurry at 300 ° C. Hold at ˜420 ° C. for 5 to 120 minutes to solubilize soluble components in the coal. This is because a temperature lower than 300 ° C. is insufficient to weaken the bonds between the molecules constituting the coal, and the proportion of soluble components that can be extracted from the coal decreases. On the other hand, at a temperature higher than 420 ° C., the pyrolysis reaction of coal becomes active, and recombination of the generated pyrolysis radicals occurs, so that the ratio of soluble components that are extracted also decreases. On the other hand, at a temperature of 300 to 420 ° C., bonds between the molecules constituting the coal are loosened, mild pyrolysis occurs, and the proportion of soluble components extracted from the coal increases. At this time, the mild pyrolysis of coal produces an aromatic-rich component mainly having an average boiling point (Tb50: 50% distillation temperature) of 200 to 300 ° C., which is effectively used as a part of the organic solvent. it can.

  The temperature at which the obtained slurry is separated into a supernatant and a solid phase component concentrate by gravity sedimentation is preferably 300 ° C. or higher and 420 ° C. or lower. This is because if it is lower than 300 ° C., a part of the component dissolved in the liquid phase component may be precipitated, and the yield of ashless coal may be reduced.

  As the organic solvent, a solvent having high coal dissolving power is preferable, and an organic solvent containing a bicyclic aromatic compound approximate to a coal structural unit as a main component is preferable. The organic solvent preferably has a boiling point of 180 ° C to 330 ° C. When the boiling point is lower than 180 ° C., the recovery rate of the organic solvent evaporated and removed from the supernatant may be lowered. On the other hand, when the boiling point exceeds 330 ° C., it is difficult to separate the coal and the organic solvent, and the recovery rate of the organic solvent may be lowered. Specific examples of the bicyclic aromatic compound include aliphatics such as naphthalene (boiling point: 218 ° C); methylnaphthalene (boiling point: 241 to 242 ° C), dimethylnaphthalene (boiling point: 261 to 272 ° C), and trimethylnaphthalene. Examples thereof include naphthalene having a side chain; biphenyl; biphenyl having an aliphatic side chain or an aromatic substituent, or a mixture thereof.

  Examples of coal having a carbon content (daf) of 60% or more and less than 95% used as a starting material for producing ashless coal have the following characteristics, for example. It is preferable to use one. The volatile content of the non-caking coal or the like is preferably 30% or more, more preferably 32% or more, preferably 40% or less, more preferably 36% or less. The average reflectance of the non-caking coal or the like is preferably 0.6 or more, more preferably 0.8 or more, preferably 1.0 or less, more preferably 0.9 or less. The total inert such as non-caking coal is preferably 5% or more, more preferably 15% or more, preferably 35% or less, more preferably 20% or less. The Gieseler maximum fluidity (logMFD) such as the non-coking coal is preferably 3.0 (logddpm) or more, more preferably 3.3 (logddpm) or more, preferably 4.5 (logddpm) or less. It is preferably 3.6 (logddpm) or less. The volatile content can be measured by the method specified in JIS M8812, the average reflectance can be measured by the method specified by JIS M8816, and the Gieseler maximum fluidity (logMFD) can be measured by the Gieseler plastometer method specified by JIS M8801. Further, the total inert (TI) is calculated by the following formula using the ratio of semi-fujinite and the ratio of the microstructure component group (maceral group) in the analysis value of the coal microstructure component (maceral) of JIS M8816. be able to.

  In the formula, MM (mineral matter) means a mineral, A means ash (anhydrous base, measured by JIS M8812), and S means a total sulfur content (anhydrous base, measured by JIS M8813).

  In the present invention, the ashless coal obtained as described above is preferably pulverized and controlled to have a desired particle size. Examples of the pulverization method include a jet mill, a hammer mill (impact pulverizer) equipped with a screen, a roller mill, a rolling ball mill, a vibration mill, a stirring mill, and the like. This is a preferred embodiment. Among these, it is a preferable aspect to pulverize a combination of a hammer mill equipped with a screen and a jet mill. Ashless coal does not contain ash such as silicic acid, alumina, iron oxide, lime, magnesia, alkali metal, etc., so that the particle diameter can be easily reduced by pulverization.

  In the present invention, the content of the ashless coal in the raw coal is preferably set as appropriate according to the particle size of the ashless coal to be used, but is usually preferably 15% by mass or less, and 12% by mass or less. Is more preferable. This is because if the content exceeds 15% by mass, the proportion of coal having a carbon content (daf) of 60% or more and 91% or less decreases, and the resulting coke strength may decrease. Although the minimum of the content rate of the said ashless coal which occupies for raw coal is not specifically limited, 1 mass% is preferable and 3 mass% is more preferable. When the raw coal contains 1% by mass or more of the ashless coal, the effect of improving the obtained coke strength is increased.

  Next, coal having a carbon content (daf) of 85% or more and 91% or less, and coal having a carbon content (daf) of 60% or more and less than 85%. Will be described.

  Coal having a carbon content (daf) of 85% or more and 91% or less in raw coal is blended to increase the strength of the obtained coke, and the blending thereof. The amount is preferably 16% by mass or more, and more preferably 20% by mass or more when the entire raw coal is 100% by mass. When the blending amount of the strong caking coal is less than 16% by mass, the caking component is too short, and even if ashless coal is added, a desired coke strength may not be obtained. On the other hand, the upper limit of the amount of strongly caking coal is not particularly limited, but 45% by mass is preferable. It is because the raw material cost at the time of coke manufacture will rise when the compounding quantity of strong caking coal increases too much.

  As the coal having a carbon content (daf) of 60% or more and less than 85%, the carbon content (daf) is preferably 78% or more and 83%. Less than slightly caking coal, non-caking coal, or a mixture thereof can be mentioned. Coal having a carbon content (daf) of 60% or more and less than 85% (non-caking coal, etc.) so that the total blending amount with strong caking coal and ashless coal becomes 100% by mass It is preferable to mix.

  As a combination of coal having a carbon content (daf) of 85% to 91% and coal having a carbon content (daf) of 60% to less than 85%, for example, The aspect which consists of a strong caking coal and a weak caking coal, the aspect which consists of a strong caking coal and a non-caking coal, the aspect which consists of a strong caking coal, a weak caking coal, and a non-caking coal are mentioned. Can do.

  In the present invention, a blended coal obtained by blending strongly caking coal and non-caking coal (not including ashless coal used in the present invention) preferably has the following characteristics. The volatile content of the blended coal is preferably 15% or more, more preferably 26% or more, preferably 35% or less, more preferably 29% or less. The average reflectance of the blended charcoal is preferably 0.65 or more, more preferably 1.00 or more, preferably 1.60 or less, more preferably 1.10 or less. The total inert of the blended coal is preferably 15% or more, more preferably 20% or more, preferably 35% or less, more preferably 23% or less. The Gieseler maximum fluidity (logMFD) of the blended coal is preferably 0.7 (logddpm) or more, more preferably 2.0 (logddpm) or more, preferably 3.5 (logddpm) or less, more preferably 2 .3 (logddpm) or less. The particle size constitution of the blended coal is preferably 3 mm or less, preferably 50% or more, more preferably 75% or more, preferably 90% or less, more preferably 85% or less. The wide numerical range of each characteristic is a suitable range that can be used as a raw material for blast furnace coke, and by making each characteristic within a narrower numerical range, there is a coke that is substantially insignificant in strength. can get.

  The method for producing coke according to the present invention includes a coal having a carbon content (daf) of 85% to 91% and a carbon content (daf) of 60% to less than 85%. It is characterized by dry-distilling raw coal containing coal and coal substantially containing no ash and having a particle diameter of less than 1 mm.

  The conditions of the carbonization are not particularly limited, and normal carbonization conditions in coke production using a coke oven can be adopted, for example, 950 ° C or higher, more preferably 1000 ° C or higher, 1200 ° C or lower, More preferably, it is preferably carbonized at a temperature of 1050 ° C. or less for 8 hours or longer, more preferably 10 hours or longer, more preferably 24 hours or shorter, more preferably 20 hours or shorter.

  The present invention includes a pig iron manufacturing method characterized by using coke obtained by the coke manufacturing method of the present invention. Since the coke obtained by the production method of the present invention is excellent in strength, it can be suitably used for producing pig iron in a blast furnace. That is, if coke obtained by the production method of the present invention is used, gas permeability at the time of pig iron production in a blast furnace is improved. The pig iron production method in the blast furnace may be a known method. For example, iron ore and coke are alternately layered in the blast furnace, and hot air from the bottom of the blast furnace, and if necessary, pulverized coal. Can be mentioned.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range.

[Preparation of ashless charcoal]
Ashless charcoal was prepared by the following method using the apparatus of FIG. Australian caking coal (carbon content (daf) 84%) and 1-methylnaphthalene were mixed in tank 1 (Australian caking coal: 1-methyltaphthalene = 20% by mass: 80 (Mass%) slurry was prepared. The obtained slurry was heated to 370 ° C. by the preheater 3, and soluble components were extracted from the caking coal produced in Australia in the extraction tank 4. The slurry after the extraction treatment is supplied to the gravity sedimentation tank 5 at a flow rate of 15 kg / h, gravity sedimentation is performed, and the supernatant liquid and the solid phase component concentrate are separated. The supernatant liquid is filtered at a flow rate of 3 kg / h. The solid phase component concentrate was discharged from the bottom of the gravity sedimentation tank 5 to the solid phase component concentrate receiver 6 at a flow rate of 12 kg / h. The supernatant liquid was filtered through the filter unit 8 and then recovered in the supernatant liquid receiver 9, and the organic solvent was removed from the recovered liquid by spray drying to obtain ashless coal 1 (ash content 600 ppm). The obtained ashless coal 1 was pulverized to prepare four types of ashless coal 2 to 5 having different particle diameters. Tables 1 to 5 show the particle properties of the obtained ashless coal. The ashless coal 2 is pulverized using a jaw crusher, the ashless coal 3 is pulverized using a jaw crusher and a coffee mill, and the ashless coals 4 and 5 are an impact pulverizer equipped with a screen and Seishin Co., Ltd. The pulverization was performed using a jet mill (pulverization pressure ratio 0.7 MPa / 0.7 MPa).

[Preparation of coking coal and production of coke]
As shown in Table 6, a coal having a carbon content (daf) of 85% to 91% and a coal having a carbon content (daf) of 60% to less than 85% Each of the ashless coals 1 to 5 shown in Tables 1 to 5 was blended to obtain raw coal. The prepared raw coal was charged into a retort (size: width 380 mm × length 430 mm × height 350 mm) so that the density was 720 kg / m ³ . This retort was put into a double-sided heating type electric furnace capable of heating in the width direction, and the raw coal was carbonized. The dry distillation was carried out at 1070 ° C. for 14 hours, and then the retort was taken out of the electric furnace and allowed to cool naturally over about 16 hours.

  Coke was removed from the cooled retort. The dried coke is dropped twice from a height of 2 m using a drop test device (width 455 mm, length 710 mm, depth 380 mm) shown in JIS K2151, and then a drum tester shown in JIS K2151 ( Using an inner diameter of 1500 mm and a length of 1500 mm, it was rotated at a rotational speed of 15 times per minute for 2 minutes, and an impact of a total of 30 rotational motions was applied. The sample was taken out from the drum tester and sieved with 100 mm, 75 mm, 50 mm, 25 mm, and 15 mm sieves, and the particle size distribution was measured. According to the particle size composition ratio of 25 mm or more, it was converted to 100% and blended so that the total was 10 kg, and used as a sample for strength measurement.

[Coke strength measurement]
The drum strength was measured using the obtained sample for strength measurement. The drum strength test was performed by using a drum tester (inner diameter 1500 mm, length 1500 mm) shown in JIS K2151, placing 10 kg of the sample in this container and rotating it at a rotation speed of 15 times per minute for 10 minutes. A total of 150 impacts from the rotational movement were applied. This rotation was performed so that a rotating shaft was provided at the center of the inner diameter, and the cylinder was rotated around the rotating shaft so that the cylindrical drum drawn a circle with a diameter of 1500 mm. After applying an impact by the prescribed 150 rotations, a sample was taken out from the cylindrical container, and divided by a 15 mm sieve to measure the mass on the sieve. At this time, the mass caught on the sieve was also measured on the sieve and the mass was measured. The drum strength index (DI ¹⁵⁰ ₁₅ ) was calculated as follows. The results are shown in Table 7.
Drum strength index (DI ¹⁵⁰ ₁₅ ) = 100 × 15 mm Mass on sieve (unit: g) / 10000 g

In general, the rotational strength of coke is divided into one that evaluates volume fracture in which a coke lump is broken as a large lump and one that evaluates surface fracture due to surface wear, but the drum strength used in the present invention The index (DI ¹⁵⁰ ₁₅ ) is interpreted as an index used to evaluate both cracking at a crack due to volume fracture and subsequent surface fracture. Table 8 shows the obtained change value of the coke strength index (= coke strength index after addition of ashless coal−coke strength index when ashless coal is not added).

  From the results of Tables 7 and 8, it can be seen that when the content of ashless coal is the same, the coke strength index increases as the particle size decreases. In particular, when the content of ashless coal is 5% to 10%, the improvement effect becomes large. Moreover, when ashless coal 4 and 5 were used, the coke strength index became large as the content rate of ashless coal became high.

FIG. 2 is a graph of Table 8 with the horizontal axis representing the particle size (mm) of ashless coal and the vertical axis representing the coke strength index change value. From this graph, an almost linear relationship is obtained between the particle size (mm) of ashless coal and the coke strength index change value, and the approximate expression can be expressed as follows. Table 9 shows the values of the coefficients a and b and the correlation coefficient in the approximate expression.
Y = a × ln (X) + b
(X: Particle size of ashless coal (mm), Y: Coke strength index change value)

  FIG. 3 uses the above approximate expression to change the Y: coke strength index change value from 1.7 to 4.8 in increments of 0.1, and back-calculate the particle size of the ashless coal at that time. It is obtained by graphing. By using this graph, the content of ashless coal is appropriately set according to the particle size of ashless coal, or the particle size of ashless coal is appropriately set according to the content of ashless coal. can do. For example, in order to increase the coke strength index by 2.0, ashless coal having a particle size of about 0.21 mm may be contained by 10 mass%, or ashless coal having a particle size of about 0.14 mm may be added. It turns out that 5 mass% should be contained. However, production efficiency tends to decrease as the ashless coal has a smaller particle size. Therefore, in view of industrial productivity, it is preferable to use ashless coal having a particle size as large as possible by containing 5 mass% or more of ashless coal.

  The present invention can be suitably applied to the production of coke and further to the production of pig iron in a blast furnace.

Explanatory drawing which illustrates the apparatus and process which manufacture ashless coal used by this invention. The graph which shows the relationship between a coke strength index change value and the particle diameter of ashless coal. The graph which shows the relationship between a coke strength index change value and the particle diameter of ashless coal.

Explanation of symbols

1: tank, 2: pump, 3: preheater, 4: extraction tank, 5: gravity sedimentation tank, 6: solid phase component concentrate receiver, 7: filter member, 8: filter unit, 9: supernatant receiver 10: Stirrer, 13: Stirrer

Claims (6)

Coal with a carbon content (daf) of 85% to 91%;
Coal having a carbon content (daf) of 60% or more and less than 85%;
Ash content be substantially a coal containing no to dry distillation of raw material coal particle child size containing a coal of less than 1mm Turkey Kusu manufacturing method,
Coal containing substantially no ash is obtained by pulverizing a soluble component obtained by extraction using an organic solvent from coal having a carbon content (daf) of 60% or more and less than 95%. A method for producing coke, which is characterized by being used .   The method for producing coke according to claim 1, wherein the coal substantially not containing ash has a particle diameter of less than 0.5 mm.   The method for producing coke according to claim 1, wherein the coal substantially not containing ash has a particle diameter of less than 0.15 mm.   The manufacturing method of the coke as described in any one of Claims 1-3 which dry-coal the raw material coal whose content rate of the coal which does not contain the said ash content substantially is 15 mass% or less. The said organic solvent is an organic solvent which has a bicyclic aromatic compound as a main component, The manufacturing method of the coke as described in any one of Claims 1-4 . The manufacturing method of pig iron characterized by using the coke obtained by the manufacturing method of the coke as described in any one of Claims 1-5 .

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