JP6174004B2 - Carbon material manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a carbon material and a carbon material.

  Carbon materials mainly formed of carbon have electrical conductivity, heat resistance, chemical stability, etc., and are excellent in mechanical strength. For example, they are widely used as structural materials, conductive materials, mechanical component materials, etc. Yes. In general, a carbon material is produced by forming an organic raw material (carbon material raw material) into a lump and heating and carbonizing the formed body at a high temperature.

  Specifically, coal pitch coke, that is, coke made from coal pitch, is used as the aggregate of the organic material molded body, and tar or pitch is used as the molding binder. As the coal pitch coke used as the aggregate, for example, an unused component when producing coke for iron making or the like is mainly used. Tars and pitches are also by-products when coal is carbonized. For this reason, the production amount of the organic raw material for producing the carbon material is restricted by the production amount of the main process such as the production of iron coke. That is, it is not possible to freely produce only coal pitch coke and pitch, which are organic materials for carbon material production.

  In addition, coal pitch coke, tar and pitch, which are by-products of other production processes, contain ash in their components. Therefore, although ash remains in the carbon material manufactured using these materials, the ash causes a disadvantage that the characteristics of the carbon material are deteriorated.

  Thus, it has been studied to use ashless coal formed by pyrolysis and solvent extraction of coal as an organic raw material. However, ashless coal has a high softening point and is not easy to mold. Moreover, even when using ashless coal, the problem that a molded object expand | swells when carbonizing by heating similarly to the case where coal is used as an organic raw material remains. For this reason, it has been proposed to suppress expansion during carbonization of a molded body of an organic raw material by removing low molecular weight components by heat-treating ashless coal (see JP 2011-1240 A).

  However, even the method of modifying ashless coal described in the above publication cannot completely prevent deformation during carbonization of the molded body of the organic raw material, and the dimensional stability during carbonization of the molded body of the organic raw material is not improved. Further improvement is desired.

Refer to JP 2011-1240 A

  In view of the above problems, an object of the present invention is to provide a method for producing a carbon material having high dimensional stability during carbonization and a carbon material having high dimensional accuracy.

  The invention made in order to solve the above-mentioned problems is a combination of a step of separating ashless coal obtained from coal into a soluble component and an insoluble component by a solvent extraction process, and at least a part of this soluble component or insoluble component. It is a manufacturing method of a carbon material provided with the process of carrying out, the process of shape | molding this compound, and the process of carbonizing the shape | molded compound.

  According to the method for producing the carbon material, the ashless coal obtained from coal is separated into a soluble component and an insoluble component by solvent extraction treatment, and carbonized at least a part of these is blended. The ratio of the amount of the binder component that can contain the component and the amount of the aggregate that can contain the insoluble component can be optimized. In addition, the soluble component obtained by the solvent extraction treatment has a softening temperature preferable as a binder for forming a molded body of an organic raw material for obtaining a carbon material by carbonization because of a small content of the high molecular weight component. On the other hand, the soluble component having a low molecular weight is removed by the solvent extraction process, and therefore the insoluble component is difficult to melt during carbonization or expand due to volatilization of the low molecular weight component. Therefore, a carbon material having a relatively high dimensional accuracy can be manufactured by the carbon material manufacturing method.

  In the blending step, the soluble component and the insoluble component may be blended. Thus, by blending and using both the soluble component and the insoluble component, the physical properties of the binder can be optimized and deformation of the aggregate can be more effectively suppressed. In particular, by blending ashless charcoal separated into soluble and insoluble components before carbonization, the soluble components are less likely to deform the insoluble components during carbonization, so dimensional stability during carbonization is further improved. It can be improved.

  The solvent extraction treatment temperature in the separation step is preferably 200 ° C. or lower. Thus, it can prevent that the softening temperature of the said soluble component becomes high too much by making the solvent extraction processing temperature in a isolation | separation process below the said upper limit. That is, a soluble component can be made more preferable as a binder.

  A step of heat-treating the insoluble component at a temperature of 400 ° C. or higher and 1000 ° C. or lower may be further provided between the separation step and the blending step. Thus, the expansion | swelling at the time of carbonization can further be suppressed by heat-processing an insoluble component. Therefore, by blending the insoluble component after heat treatment, the dimensional stability during carbonization can be further improved, and a carbon material with higher dimensional accuracy can be produced.

  Another invention made to solve the above problems is a carbon material formed by carbonizing an aggregate and a binder, and an insoluble component obtained by solvent extraction treatment of ashless coal is used as the aggregate. It is a carbon material characterized by using a soluble component obtained by solvent extraction treatment of ashless coal as the binder.

  Here, “ashless coal” is a modified coal obtained by modifying coal and has an ash content of 5% by mass or less. In the present invention, the ash content is particularly 1% by mass. The following are preferable, and those having both ash content of 0.5% by mass or less are more preferable. In addition, "ash content" means the value measured based on JIS-M8812 (2004).

  In the carbon material, the soluble component obtained by the solvent extraction treatment of ashless coal has an appropriate softening temperature as a binder, and the insoluble component obtained by the solvent extraction treatment of ashless coal is a preferred dimension stable as an aggregate. Have sex. Therefore, the carbon material has small deformation during carbonization and high dimensional accuracy.

  As described above, the method for producing a carbon material of the present invention can produce a carbon material having high dimensional stability during carbonization and high dimensional accuracy. The carbon material of the present invention has high dimensional accuracy.

It is a flowchart which shows the procedure of the manufacturing method of the carbon material of one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

[Method for producing carbon material]
As shown in FIG. 1, the method for producing a carbon material according to an embodiment of the present invention includes a step of forming ashless coal by pyrolysis and solvent extraction treatment of coal (ashless coal forming step: step S1), A step of separating ashless coal obtained from coal into a soluble component and an insoluble component by low-temperature solvent extraction treatment (separation step: step S2), a step of heat-treating the obtained insoluble component (heat treatment step: step S3), , A step of blending at least a part of a soluble component or an insoluble component (blending step: step S4), a step of molding this blend (molding step: step S5), and a step of carbonizing the molded blend (carbonization) Step: Step S6).

<Ashless coal formation process>
In the ashless coal formation step of step S1, ashless coal is obtained by heating a slurry obtained by mixing coal and a solvent to a temperature equal to or higher than the pyrolysis temperature of coal and extracting the pyrolyzed coal soluble components into the solvent. . The kind of raw coal of ashless coal is not specifically limited, For example, various well-known coals, such as bituminous coal, subbituminous coal, lignite, lignite, can be used. Among these, low-grade coals such as subbituminous coal, lignite, and lignite are preferable from the viewpoint of economy.

  The solvent is not particularly limited as long as it has a property of dissolving coal. For example, monocyclic aromatic compounds such as benzene, toluene, and xylene, and bicyclic rings such as naphthalene, methylnaphthalene, dimethylnaphthalene, and trimethylnaphthalene. Aromatic compounds and the like can be used. The bicyclic aromatic compound includes naphthalene having an aliphatic chain and biphenyl having a long aliphatic chain.

  Among the above solvents, a bicyclic aromatic compound which is a coal derivative purified from a coal carbonization product is preferable. The bicyclic aromatic compound of the coal derivative is stable even in a heated state and has an excellent affinity with coal. Therefore, by using such a bicyclic aromatic compound as a solvent, the ratio of coal components extracted into the solvent can be increased, and the solvent can be easily recovered and reused by a method such as distillation. .

  As a minimum of heating temperature (pyrolysis extraction temperature) of a slurry, 300 ° C is preferred, 350 ° C is more preferred, and 380 ° C is still more preferred. On the other hand, the upper limit of the heating temperature of the slurry is preferably 470 ° C, more preferably 450 ° C. If the heating temperature of the slurry is less than the above lower limit, the bonds between the molecules constituting the coal cannot be sufficiently weakened. For example, when low grade coal is used as the raw coal, There is a possibility that the solidification temperature cannot be increased, and the yield may be low and uneconomical. On the other hand, when the heating temperature of the slurry exceeds the above upper limit, the thermal decomposition reaction of coal becomes very active and recombination of generated thermal decomposition radicals occurs, which may reduce the extraction rate.

  The extraction rate from coal in the ashless coal formation step (the yield of ashless coal) is, for example, 40% by mass or more and 60% by mass or less, although it depends on the quality of the coal as a raw material.

<Separation process>
In the separation process of step S2, a comparatively low-molecular-weight soluble component that is solvent-extracted and a solvent-extracted comparison by subjecting the ash-free coal obtained in the ashless coal formation process of step S1 to a low-temperature solvent extraction process Separated into insoluble components of high molecular weight. As a result, a soluble component suitable for imparting moldability by blending as a binder with an organic raw material of carbon material, and an insoluble component suitable for use as an aggregate of organic raw material that can be carbonized with a small dimensional change. And is obtained.

  More specifically, a slurry in which ashless coal is dispersed in a solvent is prepared, and this slurry is held within a predetermined temperature range for a certain period of time, and then a solid content, that is, an insoluble component, and a liquid content, that is, a soluble component in the slurry. Separate the eluted solution.

  The lower limit of the average particle size of the ashless coal dispersed in the solvent is preferably 50 μm, and more preferably 100 μm. On the other hand, as an upper limit of the average particle diameter of ashless coal, 5 mm is preferable and 3 mm is more preferable. If the average particle size of the ashless coal is less than the above lower limit, it may be difficult to separate the soluble component solution and the insoluble component in the separation step of Step S2, and the ashless coal handling property and production efficiency may be low. May be insufficient. Conversely, if the average particle size of the ashless coal exceeds the above upper limit, the extraction rate of the soluble component in the separation step of step S2 may be low, or the particle size of the insoluble component obtained in the separation step is increased, It may be necessary to further grind insoluble components. The “average particle size” means a particle size at which the volume integrated value is 50% in the particle size distribution measured by the laser diffraction scattering method.

  The lower limit of the mixing ratio of ashless coal with respect to the solvent of the slurry is preferably 5% by mass, and more preferably 10% by mass. On the other hand, the upper limit of the mixing ratio of ashless coal to the solvent is preferably 40% by mass, and more preferably 30% by mass. If the mixing ratio of ashless coal to the solvent is less than the above lower limit, the production efficiency is low, which may be uneconomical. Conversely, when the mixing ratio of ashless coal with respect to the solvent exceeds the above upper limit, handling of the slurry and separation of insoluble components may be difficult.

  A method for separating the solvent from which the soluble component is eluted from the insoluble component is not particularly limited, and a known separation method such as a filtration method, a centrifugal separation method, or a gravity sedimentation method can be employed. Among these, the gravity sedimentation method which can continuously operate the fluid and is suitable for a large amount of processing at a low cost is preferable. In the gravity sedimentation method, a liquid in which a soluble component is dissolved in a solvent is separated as a supernatant in the upper part of the gravity sedimentation tank, and a solid content liquid in which an insoluble component is settled in the lower part of the gravity sedimentation tank.

  Then, by removing the solvent from the liquid (supernatant liquid) from which the insoluble component has been separated, the soluble component of the ashless coal is separated and recovered, and the solvent is removed from the solid concentrate to thereby dissolve the ashless coal insoluble. The components are separated and recovered. It does not specifically limit as a method of removing a solvent from the said supernatant liquid and solid concentration liquid, A general distillation method, an evaporation method, etc. can be used. In particular, the removal of the solvent from the insoluble component is preferably performed by distillation in order to recover and reuse the solvent.

  The solvent used in the separation step may be any solvent that can elute low molecular weight components of ashless coal, and the same solvents as those used in the ashless coal formation step can be used. The solvent for the separation step is preferably a low molecular weight solvent that can obtain a sufficient extraction rate at a low temperature, and examples of such a preferable solvent include acetone, pyridine, tetrahydrofuran, and the like.

  The solvent extraction processing temperature in the separation process varies depending on the type of solvent. However, generally, the upper limit of the solvent extraction treatment temperature is preferably 200 ° C, more preferably 150 ° C, and even more preferably 100 ° C. On the other hand, the lower limit of the solvent extraction treatment temperature is not particularly limited, but normal temperature, for example, 20 ° C. is preferable. When the solvent extraction treatment temperature exceeds the above upper limit, the molecular weight of the soluble component to be extracted increases, so that the softening temperature becomes too high, and it is likely that the compounding of the soluble component and the molding of the compound are not easy. Conversely, when the solvent extraction treatment temperature is less than the above lower limit, cooling is required, and the cost may increase unnecessarily.

  The lower limit of the extraction time in the separation step, that is, the time maintained at the solvent extraction treatment temperature is preferably 10 minutes, and more preferably 15 minutes. On the other hand, the upper limit of the extraction time is preferably 120 minutes, more preferably 90 minutes. When extraction time is less than the said minimum, there exists a possibility that the low molecular weight component of ashless coal may not fully be eluted. Conversely, when the extraction time exceeds the above upper limit, the manufacturing cost may increase unnecessarily.

  As a minimum of the extraction rate of the soluble component from ashless coal in a separation process, 7 mass% is preferred and 10 mass% is more preferred. On the other hand, the upper limit of the extraction rate of soluble components from ashless coal is preferably 60% by mass, and more preferably 50% by mass. If the extraction rate of soluble components from ashless coal in the separation process is less than the above lower limit, the recovery amount of soluble components may be insufficient, or low molecular weight components may remain in the insoluble components, and the size during carbonization Stability may be insufficient. On the contrary, when the extraction rate of the soluble component from the ashless coal in the separation step exceeds the above upper limit, the softening temperature of the soluble component becomes high, and the blending and molding of the organic raw material may not be easy.

  The softening temperature of the soluble component obtained in the separation step is determined by the conditions of the solvent extraction treatment, such as the type of solvent, the solvent extraction treatment temperature, and the like. As a minimum of the softening temperature of this soluble component, 45 degreeC is preferable and 60 degreeC is more preferable. On the other hand, as an upper limit of the softening temperature of a soluble component, 200 degreeC is preferable and 120 degreeC is more preferable. When the softening temperature of the soluble component is less than the lower limit, it may be unintentionally softened before blending into the organic raw material in the blending step of Step S4, and handling may be difficult. Conversely, if the softening temperature of the soluble component exceeds the above upper limit, it may be necessary to heat to a relatively high temperature for blending and forming the organic raw material, which may make it difficult to blend and form the organic raw material, There is a risk that the cost of blending and forming the raw materials increases. The “softening temperature” is a value measured by a ring and ball method in accordance with ASTM-D36.

  The upper limit of the volume expansion coefficient when carbonizing the insoluble component is preferably 3 times, and more preferably 2 times. When the volume expansion coefficient when carbonizing an insoluble component exceeds the above upper limit, when an organic raw material containing this insoluble component as at least a part of the aggregate is carbonized, there is a possibility that a dimensional change during carbonization becomes large.

<Heat treatment process>
In the heat treatment process of step S3, the low molecular weight component is volatilized by heating the insoluble component obtained in the separation process of step S2. Preferably, the insoluble component is carbonized by heating in an inert gas atmosphere. Thereby, the expansion | swelling of the insoluble component in the carbonization process of step S6 mentioned later can be suppressed.

  As a heat treatment method, a method using a known heat treatment furnace can be applied. Although it does not specifically limit as a heat treatment furnace used, For example, a pot furnace, a lead hammer furnace, a kiln, a rotary kiln, a shaft furnace, a chamber furnace etc. can be mentioned.

  As a minimum of the heat processing temperature in the said heat processing process, 400 degreeC is preferable and 500 degreeC is more preferable. On the other hand, the upper limit of the heat treatment temperature is preferably 1000 ° C., more preferably 800 ° C. When the said heat processing temperature is less than the said minimum, the low molecular weight component in an insoluble component cannot fully be removed, and there exists a possibility that an insoluble component may expand | swell at the time of carbonization. On the other hand, when the heat treatment temperature exceeds the upper limit, the energy cost may increase unnecessarily.

  As a minimum of the heat processing time in the said heat processing process (time hold | maintained at the said heat processing temperature), 10 minutes are preferable and 15 minutes are more preferable. On the other hand, the upper limit of the heat treatment time in the heat treatment step is preferably 90 minutes, and more preferably 60 minutes. When the heat treatment time in the heat treatment step is less than the lower limit, the low molecular weight component may not be sufficiently removed. Conversely, when the heat treatment time in the heat treatment step exceeds the upper limit, the treatment cost may be unnecessarily increased.

  In this heat treatment step, the particles of the insoluble component can be melted, so that the particles may be bound or fused to become coarse. In this case, it is preferable to grind the particles that have been coarsened so as to have the above average particle diameter.

<Mixing process>
In the blending step of step S4, an aggregate and a binder are blended to form a blend that becomes an organic raw material. Specifically, the blending of the insoluble component obtained in the separation step of step S2 as at least a part of the aggregate, or the blending of the soluble component obtained in the separation step of step S2 as at least a part of the binder. Do. This blend preferably contains the insoluble component in the aggregate and the soluble component in the binder.

  As an aggregate mix | blended with an organic raw material, coal, coal pitch coke (coal pitch coke), ashless coal, etc. other than the insoluble component obtained at the separation process of step S2 can be used, for example.

  As a binder mix | blended with an organic raw material, pitch, tar, ashless coal, etc. other than the usable component obtained at the separation process of step S2 can be used, for example.

  The combination of the aggregate and the binder is performed at a temperature equal to or higher than the softening temperature of the binder, and the aggregate and the binder are kneaded. As a minimum of the difference of this compounding temperature and the softening temperature of a binder, 20 ° C is preferred and 30 ° C is more preferred. A specific blending temperature is, for example, 70 ° C. or higher and 200 ° C. or lower.

  As a minimum of a compounding rate of a binder to the whole blend, 5 mass% is preferred and 10 mass% is more preferred. On the other hand, as an upper limit of the compounding ratio of the binder with respect to the whole compound, 40 mass% is preferable and 30 mass% is more preferable. If the blending ratio of the binder with respect to the entire blend is less than the above lower limit, the caking property of the blend may not be obtained, and molding may be difficult in the molding process of Step S5, or molding in the carbonization process of Step S6. Your body may collapse. On the other hand, when the blending ratio of the binder with respect to the entire blend exceeds the above upper limit, the blend may be fluidized in the carbonization process in step S6 and the molded body may be deformed, or a part of the binder is molded in the carbonization process in step S6. The molded body may expand due to evaporation inside the body.

  As a minimum of the content rate of the said insoluble component in the aggregate of the said mixture, 50 mass% is preferable and 90 mass% is more preferable. On the other hand, it does not specifically limit as an upper limit of the content rate of the said insoluble component in an aggregate, It can be 100 mass%. When the content ratio of the insoluble component in the aggregate is less than the lower limit, the ratio of the aggregate having poor dimensional stability increases, and as a result, the effect of preventing the dimensional change in the carbonization step in step S6 may be insufficient. There is.

  As a minimum of the content rate of the said soluble component in the binder of the said mixture, 50 mass% is preferable and 90 mass% is more preferable. On the other hand, it does not specifically limit as an upper limit of the content rate of the said soluble component in a binder, It can be 100 mass%. If the content of the soluble component in the binder is less than the above lower limit, the binder may have insufficient caking strength, resulting in insufficient moldability in the molding step of Step S5, or the binder in the formulation. When the ratio is increased, there is a possibility that a dimensional change in the carbonization process in Step S6 is increased.

<Molding process>
In the molding process of step S5, the compound formed in the compounding process of step S4 is molded into the shape of a desired carbon material to be finally obtained.

  It does not specifically limit as a shaping | molding method of the said compound, For example, well-known methods, such as compression molding, extrusion molding, and a double roll type tablet molding, can be used.

<Carbonization process>
In the carbonization process of step S6, a carbon material having a desired shape is obtained by heating and carbonizing the molded body formed in the molding process of step S5.

  Specifically, the molded body is charged into an arbitrary heating device such as an electric furnace, the inside is replaced with a non-oxidizing gas, and then heated while blowing the non-oxidizing gas into the heating device.

  The optimum heat treatment temperature in the carbonization step varies depending on the characteristics required for the carbon material to be produced, but the lower limit of the heat treatment temperature is preferably 500 ° C, more preferably 700 ° C. On the other hand, as an upper limit of heat processing temperature, 3000 degreeC is preferable and 2800 degreeC is more preferable. When the heat treatment temperature is less than the lower limit, carbonization may be insufficient. Conversely, when the heat treatment temperature exceeds the above upper limit, the production cost may increase from the viewpoint of improving the heat resistance of the equipment and fuel consumption. Moreover, as a temperature increase rate, it can be 0.01 degree-C / min or more and 5 degrees C / min or less, for example.

  The heating time in the carbonization process may be appropriately set depending on the characteristics required of the carbon material, and is not particularly limited, but the heating time is preferably 0.5 hours or more and 10 hours or less. If the heating time is less than the lower limit, carbonization may be insufficient. Conversely, when the heating time exceeds the above upper limit, the production efficiency of the carbon material may be reduced.

  The non-oxidizing gas is not particularly limited as long as it can suppress the oxidation of the carbon material, but nitrogen gas is preferable from an economical viewpoint.

[Carbon material]
1 is a carbon material formed by carbonizing an aggregate and a binder, using an insoluble component obtained by a solvent extraction process of ashless coal as an aggregate, and using no insoluble as a binder. A carbon material using a soluble component obtained by solvent extraction treatment of ash coal is produced.

[advantage]
In the method for producing a carbon material, when an insoluble component obtained by separating ashless coal by solvent extraction is used as an aggregate, there are few impurity mineral components (ash) and low molecular weight components in the aggregate. In addition, when ashless coal is separated after being separated into an insoluble component and a soluble component, the soluble component is easily detached from the molded body of the organic raw material during carbonization, and the aggregate is difficult to expand. Thereby, the carbon material of the desired shape with high dimensional accuracy can be manufactured.

  Moreover, in the manufacturing method of the said carbon material, when the soluble component obtained by isolate | separating ashless coal by a solvent extraction process is used as a binder, there are few high molecular weight components in a binder. Thereby, the molded object of the organic raw material can be formed at a relatively low temperature, and the manufacturing cost of the carbon material can be reduced. In addition, by using a binder with a low content of high molecular weight components and a high caking power, it is possible to form an organic material molded body by caking aggregate with a relatively small amount of binder. The deformation can be further suppressed, and the dimensional accuracy of the obtained carbon material can be further improved.

  Further, in the method for producing a carbon material, ashless coal is separated into a soluble component and an insoluble component, and therefore by adjusting these ratios, an organic substance is formed in accordance with the shape and size of the carbon material to be produced. The caking property of the raw material can be adjusted freely.

[Other Embodiments]
The said embodiment does not limit the structure of this invention. Therefore, in the above-described embodiment, the components of each part of the above-described embodiment can be omitted, replaced, or added based on the description and common general knowledge of the present specification, and they are all interpreted as belonging to the scope of the present invention. Should.

  The method for producing a carbon material of the present invention does not require that ashless coal be produced from coal by itself. That is, in the method for producing a carbon material of the present invention, ashless coal produced by a third party may be used as a starting material.

  In the method for producing the carbon material, the heat treatment step can be omitted.

  The carbon material manufacturing method may include a step of further graphitizing the carbon material by heating to a higher temperature than the carbonization step in a non-oxidizing atmosphere after the carbonization step.

  EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not interpreted limitedly based on description of this Example.

  Examples 1 to 4 of the carbon material were prototyped by an ashless coal forming process, a separation process, a heat treatment process, a blending process, a forming process, and a carbonizing process described below. Moreover, the separation process, the heat treatment process, and the blending process were omitted, and a comparative example 1 of a carbon material was prototyped by an ashless coal forming process, a molding process, and a carbonizing process.

  Table 1 shows differences in production conditions between Examples 1 to 4 and Comparative Example 1 and various measured values in the production process.

(Ashless coal formation process)
The ashless coal used as a raw material in Examples 1 to 4 and Comparative Example was produced using bituminous coal that is generally used as a fuel for boilers. The yield of ashless coal based on raw coal was 48% by mass.

(Separation process)
A soluble component was extracted from 100 g of the ashless coal pulverized to an average particle size of 0.25 μm or less using 1 L of a solvent. In Example 1, acetone was used as the solvent, the extraction temperature was 25 ° C., and the extraction time was 60 minutes. In Example 2, pyridine was used as the solvent, the extraction temperature was 25 ° C., and the extraction time was 60 minutes. In Example 3, methylnaphthalene was used as the solvent, the extraction temperature was 250 ° C., and the extraction time was 60 minutes. In Example 4, methylnaphthalene was used as the solvent, the extraction temperature was 25 ° C., and the extraction time was 60 minutes. As a specific separation method, insoluble components were separated by filtration under reduced pressure, and soluble components were taken out by distilling the solvent under reduced pressure.

  The ratio of the soluble component and the insoluble component obtained in this separation step was each measured as the yield (mass%) from ashless coal.

  As a result of the measurement, the extraction rate (yield) of the soluble component was 12% by mass in Example 1, 18% by mass in Example 2, 65% by mass in Example 3, and 11% by mass in Example 4. .

  Further, the softening temperature of each soluble component obtained in this separation step was measured. For comparison, the softening temperature was also measured for ashless coal. The softening temperature was measured by the ring and ball method according to ASTM-D36.

  As a result of the measurement, the softening temperature of the soluble component was 75 ° C. in Example 1, 125 ° C. in Example 2, 186 ° C. in Example 3, and 72 ° C. in Example 4. Moreover, the softening temperature of ashless coal was 245 degreeC. For reference, the softening temperature of the insoluble component of Example 1 measured in the same manner was 395 ° C.

  From these measurement results, it can be seen that the higher the extraction rate (yield) of the soluble component, the higher the softening temperature. In general, as a binder to be blended with an organic raw material for producing a carbon material, a binder that does not soften at room temperature and softens by heating as little as possible is preferable. The soluble components of Examples 1 to 4 do not soften at room temperature, and soften at a lower temperature than ashless coal used as a conventional organic raw material, and therefore have suitable characteristics as a binder for organic raw materials. I understand.

(Heat treatment process)
Each insoluble component obtained in the separation step was heat-treated in a nitrogen atmosphere. The heat treatment conditions were a heat treatment temperature of 500 ° C., a temperature increase rate from normal temperature to the heat treatment temperature of 1 ° C./min, and a heat treatment time of 30 minutes.

  The expansion rate of each insoluble component and ashless coal in this heat treatment step was measured. For comparison, ashless coal was also heat-treated in the same manner and the expansion coefficient was measured. The expansion rate is as follows. A quartz test tube having an inner diameter of 15 mm is filled with 2.0 g of a sample pulverized to a particle size of 2 mm or less, heated to 500 ° C. at 3 ° C./min, and the sample after heating relative to the height of the sample before heating Measured as the ratio of the heights.

  As a result of the measurement, the expansion coefficient of the insoluble component was 1.4 times in Example 1, 1.2 times in Example 2, 1 time in Example 3, and 2.2 times in Example 4. Moreover, the expansion rate of the ashless coal was 12 times.

  From this measurement result, the insoluble components of Examples 1 to 4 have a significantly lower expansion rate than ashless coal used as a conventional organic raw material, and have suitable characteristics as an aggregate of the organic raw material. I understand that.

(Mixing process)
For each sample, 20 parts by mass of a soluble component pulverized to an average particle size of 5 mm or less and 80 parts by mass of an insoluble component were mixed and kneaded at a temperature of 150 ° C. That is, in Examples 1 to 4, the aggregate total amount is the insoluble component, and the binder total amount is the soluble component.

(Molding process)
The blend formed in the blending step was extruded and formed into a cylindrical shape having a diameter of 25 mm and a height of 50 mm.

(Carbonization process)
The molded body and ashless coal formed in the molding step were carbonized in a nitrogen atmosphere. As the conditions for the carbonization treatment, the carbonization temperature was 1000 ° C., and the rate of temperature increase from room temperature to the carbonization temperature was 1 ° C./min.

  It was confirmed that the carbon materials of Examples 1 to 4 were small in deformation and dimensional change from the shape molded in the molding step and higher in dimensional accuracy than the carbon material of the comparative example.

  The method for producing a carbon material of the present invention is suitably applied to the production of a carbon material that requires particularly dimensional accuracy. In addition, the carbon material of the present invention is suitably used as, for example, an electrical component or a structural component that requires dimensional accuracy.

S1 Ashless coal formation process S2 Separation process S3 Heat treatment process S4 Compounding process S5 Molding process S6 Carbonization process

Claims (3)

Separating ashless coal obtained from coal into soluble and insoluble components by solvent extraction treatment;
A step of heat-treating the insoluble component at a temperature of 400 ° C. or higher and 1000 ° C. or lower after the separation step;
A step of blending the soluble component obtained in the separation step and the insoluble component obtained in the heat treatment step ;
Molding the compound,
And carbonizing the molded compound. A method for producing a carbon material. The method for producing a carbon material according to claim 1 , wherein the solvent extraction treatment temperature in the separation step is 200 ° C. or less. A method for producing a carbon material formed by carbonizing an aggregate and a binder,
With heat-treated insoluble component temperatures 400 ° C. or higher 1000 ° C. or less after separation by solvent extraction treatment of ashless coal as the aggregate, used soluble component obtained by the solvent extraction process of ashless coal as the binder carbon Material manufacturing method.

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