WO2012118151A1 - Method for producing carbon material - Google Patents

Abstract

The present invention is a method for producing a carbon material for reduction for refining of ion or a nonferrous metal, a carbon material for structures, a carbon material for electrical materials, or a carbon material that is used as a starting material for the foregoing carbon materials. The method comprises: an ash-free coal production step (S1) wherein coal is modified with use of a solvent so as to produce ash-free coal that is modified coal; an ash-free coal heating step (S2) wherein the ash-free coal produced in the ash-free coal production step (S1) is subjected to a heat treatment so as to produce modified ash-free coal that has a volatile matter content (VM) of 40% by mass or less; a molding step (S3) wherein the modified ash-free coal produced in the ash-free coal heating step (S2) is used as a main component of a molding material and molded so as to produce a molded body that has an apparent specific gravity of 0.9 g/cm³ or more; and a carbonization step (S4) wherein the molded body produced in the molding step (S3) is subjected to a carbonization treatment so as to obtain a carbon material. Consequently, a high-purity carbon material having an extremely low ash content concentration can be economically obtained, said carbon material being dense and free from deformation.

Description

Carbon material manufacturing method

The present invention is a reduction carbon material for refining ferrous or non-ferrous metals, a structural carbon material, a carbon material for electrical materials, or a carbon material used as a raw material thereof, particularly as an aggregate of an anode for aluminum electrolytic production. The present invention relates to a method for producing a carbon material to be used.

As the main raw material of the anode for aluminum electrolytic production, petroleum coke produced from the residue of the petroleum refining process is generally used. However, because petroleum coke is co-produced with transportation fuels such as gasoline, there are restrictions on the supply of raw materials, and impurities such as sulfur contained in crude oil may adversely affect aluminum purity. There are problems.

On the other hand, coal coke used for blast furnace ironmaking has properties similar to petroleum coke as carbon, and the amount is too large as a main raw material for anodes for aluminum electrolytic production. However, since it contains about 10% by mass of coal-derived ash, there is a problem in quality, so it is not used in this application.

Therefore, there can be mentioned so-called ashless charcoal (hypercoal), which has been actively developed recently from the viewpoint of a carbon material for low ash content (see, for example, Patent Document 1). Here, ashless coal is produced by extracting coal with a solvent, separating only the components soluble in the solvent, and then removing the solvent. Structurally, this ashless coal has a wide molecular weight distribution from a relatively low molecular weight component having 2 to 3 fused aromatic rings to a high molecular weight component having about 5 or 6 rings. In addition, since ash is not dissolved in a solvent, ashless coal does not substantially contain ash, exhibits high fluidity under heating, and is excellent in thermal fluidity. Some coals, like caking coal, exhibit thermoplasticity at around 400 ° C, but ashless coal generally melts at 200-300 ° C regardless of the quality of the raw coal (softening and melting). Have sex). Therefore, application development as a binder for coke production has been advanced taking advantage of this characteristic, and in recent years, attempts have been made to produce a carbon material by using this ashless coal as a carbon material raw material. .

Japanese Unexamined Patent Publication No. 2001-26791

However, the conventional method for producing a carbon material has the following problems.
As described above, ashless coal does not contain ash and has a softening and melting property, and is known to be effective as a caking additive when producing coke for iron making. Moreover, it is a property preferable as an aggregate (main raw material) of the anode for aluminum electrolysis manufacture not to contain ash. However, ashless charcoal has a high volatile content (VM) that usually exceeds 40% by mass, is inferior in self-sinterability, and softens at about 200 ° C. Thereby, even if ashless coal can be molded, deformation occurs during carbonization (carbonization) by heating the molded body to form a carbon material, and the main raw material coke (carbon material) of the anode for aluminum electrolytic production (hereinafter, There is a problem in that it cannot be used as anode coke as appropriate. Further, when the molded body is carbonized, the molded body expands greatly, and the molded body is foamed, which causes a problem in the production of anode coke. That is, when the as-produced ashless coal is carbonized, pores due to low-molecular compound gases (water vapor, CO, CO ₂ , hydrocarbons, etc.) generated during carbonization remain as they are, so that the dense ash suitable for anode coke is suitable. No coke is generated. Specifically, lump coke is not obtained and becomes powdery coke. Similar problems arise when used for carbon materials for electrical materials other than reducing carbon materials for refining ferrous or non-ferrous metals, structural carbon materials, and anode coke.

The present invention has been made in view of the above problems, and its object is to produce a carbon material that can be economically obtained a high-purity carbon material that is dense and has no deformation and has a very low ash concentration. Is to provide.

As a result of various studies by the present inventors, it is possible to adjust the volatile content of ashless coal (hereinafter referred to as VM as appropriate) to a predetermined range to reduce carbon materials for refining iron or non-ferrous metals including anode coke. The present inventors have found that it is preferable to use as a raw material for carbon materials for electrical materials other than structural carbon materials and anode coke.
Specifically, chemical treatment and physics that reduce hydrogen content such as alkyl group decomposition, aromatization reaction, decomposition of oxygen-containing functional groups, removal of low molecular weight components by heat treatment of ashless coal The VM changes gradually, and the VM of the ashless coal can be adjusted to a predetermined range. Moreover, VM can be adjusted to a predetermined range by carbonizing ashless coal. Thereby, while suppressing the expansibility of ashless coal, self-sinterability can be improved, As a result, it discovered that foaming and a deformation | transformation at the time of carbonization could be suppressed, and it came to this invention.

That is, the method for producing a carbon material for reduction, structural carbon material, carbon material for electric material, or carbon material used as a raw material for refining iron or non-ferrous metal according to the present invention is obtained by mixing coal and a solvent. The slurry is heated to extract a coal component soluble in the solvent, the slurry after extraction is separated into a liquid part and a non-liquid part, and the coal is reformed by separating the solvent from the liquid part, An ashless coal production process for producing ashless coal, which is a modified coal, and a heat treatment of the ashless coal produced in the ashless coal production process, with a volatile content (VM) of 40% by mass or less. Ashless coal heating process for producing quality ashless coal, and the modified ashless coal produced in the ashless coal heating process as a main component of the molding raw material, and molding this modified ashless coal to give an apparent specific gravity A molding process for producing a molded body of 0.9 g / cm ³ or more, and the molded body produced in the molding process And carbonization step of carbonizing the carbon material.

According to such a manufacturing method, in the ashless coal manufacturing process, ashless coal that is modified coal having an extremely low ash concentration is manufactured by reforming coal. Next, in the ashless coal heating step, the modified ashless coal having a VM of 40% by mass or less is manufactured by heat-treating the ashless coal. Next, in the molding process, the modified ashless coal is molded to an apparent specific gravity of 0.9 g / cm ³ or more, thereby suppressing expansion in the carbonization process of the next process and maintaining the strength. The Next, in the carbonization step, the molded body made of this modified ashless coal is carbonized to obtain a carbon material with an adjusted VM. And since VM of the ashless coal after heat processing is 40 mass% or less, while the expansion property of ashless coal is suppressed, self-sintering property becomes sufficient and in the case of carbonization treatment, there is no modification. Foaming of the molded body made of ash charcoal is suppressed, and the carbon material becomes dense and has no deformation, and has an extremely low ash concentration.

In the method for producing a carbon material according to the present invention, in the ashless coal heating step, the heat treatment of the ashless coal is preferably performed in the presence of the same solvent as the solvent used for reforming the coal. .
According to such a manufacturing method, heat transfer efficiency becomes high and heating of ashless coal becomes uniform by using a solvent. Furthermore, since the same solvent as the solvent used for coal reforming is used, the economy is improved.

Moreover, in the manufacturing method of the carbon material which concerns on this invention, it is preferable to perform the carbonization process of the said molded object using a rotary kiln in the said carbonization process.
According to such a manufacturing method, by using the rotary kiln, VM adjustment becomes easy, the self-sintering property of the carbon material is further improved, and deformation can be further suppressed. Moreover, a continuous carbonization process becomes possible and the economic efficiency is further improved.

According to the method for producing a carbon material according to the present invention, it is possible to obtain a carbon material which is low in ash, dense and free from deformation. Moreover, such a carbon material can be obtained economically.

It is a process flow which shows the procedure of the manufacturing method of the carbon material which concerns on this invention. It is a front view which shows the outline of a structure of a rotary kiln. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2.

Next, the carbon material manufacturing method according to the present invention will be described in detail.
As shown in FIG. 1, the method for producing a carbon material includes an ashless coal production step S1, an ashless coal heating step S2, a molding step S3, and a carbonization step S4.
Hereinafter, each step will be described.

<Ashless coal manufacturing process (S1)>
Ashless coal manufacturing process S1 is a process which modifies coal using a solvent and manufactures ashless coal which is reformed coal.
In addition, the ashless coal as used in the field of this invention is what is called hyper coal, and is manufactured by solvent-extracting coal and removing ash and an insoluble coal component. This ashless coal has very little ash (ash concentration of 1.0% by mass or less), and moisture is generally 0.5% by mass or less.

As a method for obtaining ashless coal by solvent extraction, a known method can be used, and the solvent type and production conditions are appropriately selected in view of the properties of coal and the design as a raw material for the carbon material. A typical method is to mix a coal with a solvent that has a high solvent power for coal, often an aromatic solvent (hydrogen donating or non-hydrogen donating solvent), and heat it in the coal. It is a method of extracting the organic component. However, in order to obtain ashless coal more efficiently and inexpensively, for example, it is preferable to produce ashless coal by the following method. In the method, first, a mixture (slurry) in which coal and a non-hydrogen donating solvent are mixed is heated to extract coal components that are soluble in the non-hydrogen donating solvent. Next, the slurry after extraction is separated into a liquid part and a non-liquid part, and the non-hydrogen donating solvent is separated from the liquid part to produce ashless coal.

It is preferable to use bituminous coal as the coal for ashless coal (hereinafter also referred to as raw coal). However, the coal used is not limited to bituminous coal, and inferior quality coal can be used as necessary. By using an inexpensive inferior quality carbon, the carbon material can be manufactured at a low cost, thus improving the economic efficiency. Moreover, when the moisture content of raw material coal is high, it is preferable to perform dehydration prior to solvent extraction.

In addition, inferior coal here means coals, such as a non-slightly caking coal, a general coal, a low grade coal (brown coal, subbituminous coal, etc.). Examples of the low-grade coal include lignite, lignite, and sub-bituminous coal. Further, for example, lignite coal includes Victoria coal, North Dakota coal, Berga coal, and sub-bituminous coal includes West Banco coal, Vinungan coal, Samarangau coal, and the like. The low-grade coal is not limited to those exemplified above, and any coal containing a large amount of water and desired to be dehydrated is included in the low-grade coal referred to in the present invention. The coal is preferably pulverized into as small particles as possible, and preferably has a particle size of 1 mm or less.

The non-hydrogen donating solvent is a coal derivative that is a solvent mainly composed of a bicyclic aromatic and purified mainly from a coal carbonization product. This non-hydrogen-donating solvent is stable even in a heated state and has excellent affinity with coal. Therefore, the proportion of soluble components (herein, coal components) extracted into the solvent (hereinafter also referred to as extraction rate) In addition, it is a solvent that can be easily recovered by a method such as distillation. The main components of the non-hydrogen donating solvent include bicyclic aromatic naphthalene, methyl naphthalene, dimethyl naphthalene, trimethyl naphthalene and the like, and the other components of the non-hydrogen donating solvent have an aliphatic side chain. Naphthalenes, anthracenes, fluorenes, and also include biphenyl and alkylbenzenes with long-chain aliphatic side chains.

The extraction rate of coal can be increased by heat extraction using a non-hydrogen donating solvent. In addition, unlike polar solvents, the solvent can be easily recovered, so that it is easy to circulate the solvent. Furthermore, since it is not necessary to use expensive hydrogen, a catalyst, or the like, coal can be solubilized at low cost to obtain ashless coal, and economic efficiency can be improved.

The coal concentration with respect to the solvent depends on the type of raw coal, but is preferably in the range of 3 to 50% by mass, more preferably in the range of 3 to 10% by mass on the basis of dry coal. When the coal concentration with respect to the solvent is less than 3% by mass, the proportion of the coal component extracted into the solvent decreases with respect to the amount of the solvent, which is not economical. On the other hand, the higher the coal concentration, the better. However, when it exceeds 50% by mass, the viscosity of the prepared slurry becomes high, and it becomes difficult to move the slurry and separate the liquid part and the non-liquid part described later.

The heating temperature of the slurry is preferably in the range of 300 to 450 ° C. By setting the heating temperature within this range, the bonds between the molecules constituting the coal are loosened, mild thermal decomposition occurs, and the extraction rate becomes the highest. When the heating temperature is less than 300 ° C., it tends to be insufficient to weaken the bonds between the molecules constituting the coal, and the extraction rate is difficult to improve. On the other hand, when the temperature exceeds 450 ° C., the pyrolysis reaction of coal becomes very active and recombination of the generated pyrolysis radicals occurs, so that the extraction rate is hardly improved and the alteration of coal is difficult to occur. The temperature is preferably 300 to 400 ° C.

The heating time (extraction time) is a time until reaching the dissolution equilibrium, but it is economically disadvantageous to realize it. Therefore, it varies depending on conditions such as the particle size of the coal and the type of the solvent, so it cannot be generally stated, but it is usually about 10 to 60 minutes. If the heating time is less than 10 minutes, the extraction of the coal component tends to be insufficient, while if it exceeds 60 minutes, the extraction does not proceed any further, which is not economical.

The extraction of the coal component soluble in the non-hydrogen donating solvent is preferably performed in the presence of an inert gas. This is because contact with oxygen is dangerous because it may ignite, and when hydrogen is used, the cost increases.
As the inert gas to be used, inexpensive nitrogen is preferably used, but is not particularly limited. The pressure is preferably 1.0 to 2.0 MPa, although it depends on the temperature during extraction and the vapor pressure of the solvent used. When the pressure is lower than the vapor pressure of the solvent, the solvent is volatilized and is not trapped in the liquid phase and cannot be extracted. In order to confine the solvent in the liquid phase, a pressure higher than the vapor pressure of the solvent is required. On the other hand, if the pressure is too high, the cost of the equipment and the operating cost increase, which is not economical.

Thus, the slurry after extracting a coal component is isolate | separated into a liquid part and a non-liquid part.
Here, the liquid part means a solution containing a coal component extracted into a solvent, and the non-liquid part means a solute containing a coal component insoluble in the solvent (coal containing ash, that is, ash coal).

As a method for separating a slurry into a liquid part and a non-liquid part, various filtration methods and centrifugal separation methods are generally known. However, the filtration method requires frequent replacement of the filter, and the centrifugation method tends to cause clogging with undissolved coal components, making it difficult to implement these methods industrially. Therefore, it is preferable to use a gravity sedimentation method that allows continuous operation of fluid and is suitable for a large amount of processing at low cost. Thereby, from the upper part of the gravity sedimentation tank, a liquid part (hereinafter also referred to as a supernatant liquid) containing a coal component extracted into the solvent is contained, and from the lower part of the gravity sedimentation tank, a coal component insoluble in the solvent is contained. A non-liquid part (hereinafter also referred to as a solid content concentrate) which is a solute can be obtained.

And ashless coal is obtained by isolate | separating a non-hydrogen donating solvent from this liquid part.
As a method for separating the solvent from the supernatant liquid (liquid part), a general distillation method or evaporation method (spray drying method, etc.) can be used. From the supernatant liquid, ashless coal substantially free of ash Can be obtained. This ashless coal has an ash content of 1.0% by mass or less, almost no ash content, water content of approximately 0.5% by mass or less, and a higher calorific value than raw coal. Therefore, by carbonizing this ashless coal, a high-purity carbon material having an extremely low ash concentration can be obtained.

<Ashless charcoal heating process (S2)>
Ashless coal heating process S2 is a process of heat-treating the ashless coal produced in the ashless coal production process S1.
Ashless coal is generally highly expansible and easily deformed as it is produced, so heat treatment is performed to suppress it. At that time, it is necessary to perform heat treatment so that the volatile content (VM) of the ashless coal after the heat treatment is 40% by mass or less, preferably 25 to 40% by mass. The VM is measured according to JISM8812. In addition, the atomic ratio of hydrogen and carbon in the ashless coal after the heat treatment (hereinafter, appropriately referred to as H / C atomic ratio) is preferably in the range of 0.68 or less, 0.5 to 0.00. More preferably, the range is 65.

Here, the VM of the ashless coal in the state of being produced without any treatment varies depending on the raw coal type and the production conditions of the ashless coal, but generally the VM has a high value exceeding 40% by mass. . However, when this ashless coal is heated, chemical / physical changes such as alkyl group decomposition, aromatization reaction, decomposition of oxygen-containing functional groups, removal of low molecular weight components, etc. will decrease the hydrogen content. Progresses and VM gradually decreases. Then, it adjusts so that VM may become the range of 40 mass% or less by heat processing. In addition, the as-produced ashless coal has an H / C atomic ratio of approximately 0.7 to 1.0, and the H / C atomic ratio gradually decreases due to chemical and physical changes due to heat treatment. To go. Therefore, it is preferable to adjust the H / C atomic ratio to be in the range of 0.68 or less by heat treatment.

A high value of VM exceeding 40% by mass indicates softening at about 200 ° C. and low self-sinterability. Therefore, during the carbonization in the carbonization step S4, foaming and deformation occur in the molded body made of the modified ashless coal. Even if the modified ashless coal is carbonized in the subsequent carbonization step S4, a powdery carbon material Can only get. Thus, foaming and a deformation | transformation of a molded object can be suppressed by adjusting VM to the range of 40 mass% or less by heat processing of ashless coal. On the other hand, if the VM is too small, the modified ashless coal will be too hard and it may be difficult to grind or mold. Therefore, the VM is preferably 25% by mass or more.

When the H / C atomic ratio is larger than 0.68, it indicates that the heat treatment is insufficient, and ashless coal contains a relatively large amount of hydrogen. Therefore, if the H / C atomic ratio exceeds 0.68, ashless coal (modified ashless coal) will foam during carbonization in the carbonization step S4 described later. Thus, the foaming at the time of carbonization of ashless coal (modified ashless coal) is suppressed by adjusting the H / C atomic ratio to a range of 0.68 or less by heat treatment of ashless coal. be able to. Also, the small H / C atomic ratio means that the heat treatment may be excessive, the self-sinterability becomes insufficient, and the modified ashless coal is carbonized in the subsequent carbonization step S4. However, there is a possibility that only a powdery carbon material can be obtained. Therefore, the H / C atomic ratio is preferably 0.5 or more.

The method of heat treatment of ashless coal is not particularly limited, and can be performed by a known method. Then, ashless coal is heated to 350 to 500 ° C., preferably 350 to 450 ° C. under reduced pressure, normal pressure, pressurization, or in an inert atmosphere. The required treatment time varies depending on the properties of the ashless coal and the treatment temperature, but is generally in the range of 10 minutes to 5 hours, preferably 10 minutes to 2 hours.
The VM in the ashless coal heating step S2, preferably the control of the H / C atomic ratio, is a preliminary experiment or the like, and the VM is 40% by mass or less, preferably the H / C atomic ratio is 0.68 or less. The processing temperature and processing time to be set are set from the above range, and the processing temperature and processing time are set.

Moreover, the heat treatment of ashless coal may be performed by heating the ashless coal alone or in the presence of the same solvent as that used for reforming the coal in the ashless coal production process.
That is, ashless charcoal is mixed with a solvent, made into a slurry, and heat-treated. The amount of the solvent with respect to the ashless coal is not particularly limited, but from the viewpoint of making a slurry with an appropriate viscosity, for example, the ashless coal concentration with respect to the solvent is 10 to 50% by mass on the basis of dry coal, preferably It may be in the range of 20 to 35% by mass. Moreover, you may heat-treat the ashless coal said here by heating the liquid part which is the coal component extracted by the said solvent as it is, without isolate | separating a solvent from it. In addition, the method of isolate | separating a solvent from the ashless coal after heat processing can use a general distillation method, an evaporation method (spray dry method etc.), etc.

By using a solvent, the heat transfer efficiency becomes higher than when ashless coal is heated as it is, and uniform heating becomes possible. Furthermore, the manufacturing cost can be reduced by using the same solvent as the solvent used for the reforming of coal. In addition, as a solvent used for the heat treatment of ashless coal, alkylnaphthalene, anthracene oil, and the like are preferable.

<Molding step (S3)>
In the molding step S3, the modified ashless coal produced in the ashless coal heating step S2 is used as a main component of the molding raw material, and the modified ashless coal is molded to have an apparent specific gravity of 0.9 g / cm ³ or more. This is a process for producing a molded body.
The reformed ashless coal can be molded by a known method. For example, compression molding, extrusion molding, double roll type tablet molding, and the like. Double roll tableting is preferred. In addition, when the modified ashless coal before molding is in a lump shape, it is pulverized to a particle size of about 1 mm or less before molding. If it is finely pulverized and high-pressure pressed, a molded product can be obtained relatively easily.

In the molding step S3, it is preferable to mold and compact the molded body so that the apparent specific gravity is 0.9 g / cm ³ or more. By such molding, it is possible to suppress expansion of the molded body and a decrease in strength in the carbonization step S4 of the next step. If the apparent specific gravity is less than 0.9 g / cm ³ , in the carbonization step S4, the molded body expands and the strength decreases and breaks. Specifically, the carbon material produced from the molded body is not a lump but a powder. Moreover, the upper limit of the apparent specific gravity is not particularly limited, and can be about 1.5 g / cm ³ . In consideration of productivity, economic efficiency, etc., the preferable upper limit of the apparent specific gravity is 1.2 g / cm ³ .

The apparent specific gravity is measured according to the small amount method described in “Coke Note 2001 Edition (edited by Japan Coke Association, pages 78-79)”.
The apparent specific gravity in the molding step S3 is controlled by a molding pressure set in advance in a preliminary experiment or the like, and the molding pressure is preferably 0.1 to 5 ton / cm ³ depending on the molding method.

In the molding process, the humidity may be adjusted as necessary, or an appropriate binder compound may be used. As the binder compound, known compounds such as tar, pitch, ashless coal itself, and resin can be used. Of these, ashless coal itself is most preferred because of its low ash content. Further, an appropriate filler such as carbon fiber, a light component produced as a by-product in the ashless coal production step S1, residual charcoal, or the like may be added and mixed.

When the binder compound is blended, the ratio of the modified ashless coal in the molded body is preferably 80% by mass or more. If the ratio of the modified ashless coal is less than 80% by mass, it is difficult to mold the modified ashless coal, and even if molded, the molded body expands due to the carbonization treatment in the next carbonization step S4, Since pores are generated, it is difficult to obtain a carbon material having a low porosity in a high yield. In addition, the apparent specific gravity of the carbon material tends to be low. Furthermore, it is difficult to maintain the strength of the carbon material. Therefore, it mix | blends so that the ratio of the modified ashless coal in a molded object may occupy 80 mass% or more, and it is set as a shaping | molding raw material. More preferably, it is 90% by mass or more, and more preferably 100% by mass, that is, the modified ashless coal produced in the preceding ashless coal heating step S2 is molded as it is without adding a binder compound.

<Carbonization process (S4)>
Carbonization process S4 is a process which carbonizes the molded object manufactured by said shaping | molding process S3, and uses it as a carbon material. Through this carbonization step, the modified ashless coal is carbonized to obtain a carbon material. Moreover, the solvent remaining in the modified ashless coal can be removed and recovered by this carbonization step.

The method and conditions for the carbonization treatment are not particularly limited, and can be performed using a known technique. Typically, it is steamed and heated at 550 to 1200 ° C. in an inert atmosphere such as nitrogen or argon to change the modified ashless coal to carbon, and the VM of the modified ashless coal is 40% by mass. Adjusted to: Further, the temperature rising rate is preferably 0.1 to 5 ° C./min, and the treatment time is preferably 5 to 60 minutes. This carbonization treatment may be performed under pressure using a hot isostatic pressing apparatus or the like. If necessary, a binder component such as asphalt pitch or tar may be added.
And adjustment of VM in carbonization process S4 is controlled by the process temperature which VM set beforehand by the preliminary experiment etc. will be 40 mass% or less.

There is no particular restriction on the type of heat treatment furnace used for carbonization, and a known one can be used. For example, a pot furnace, a lead hammer furnace, a kiln, a rotary kiln, a shaft furnace, or a chamber furnace can be used. A rotary kiln is preferable in that continuous carbonization treatment is possible. Moreover, since the rotary kiln heat-treats the product (carbon material) while rotating, there is no sticking of the product and a granular product can be easily obtained. Furthermore, it is not necessary to perform pulverization. The shaft furnace, particularly the vertical shaft furnace, has a problem that the product is easily fixed, and the chamber furnace has a problem that the production efficiency is low due to batch processing. In addition, it is not limited to these furnace types, You may use other furnace types.

A rotary kiln having a structure as shown in FIGS. 2 and 3 is used.
The rotary kiln is provided in an outer peripheral portion other than a cylindrical rotary drum 1 to which a workpiece, specifically, a molded body made of modified ashless coal is supplied, and both end portions 2 and 3 of the rotary drum 1. And an outer cylinder 4 that forms a heating chamber 5 between the outer peripheral surface of the rotating drum 1. The one end 2 of the outer peripheral surface of the rotary drum 1 is provided with a supply port 6 through which the object to be processed is supplied, and the other end 3 has a heat-treated object, specifically a carbonization process. Is provided with a discharge port 7 through which the carbon material produced by is discharged. Further, the outer peripheral surface of the outer cylinder 4 is separated by a heating medium supply path 11 for supplying a heating medium (for example, hot air) to the heating chamber 5, and the heating medium supply path 11 and the metal plate 10. And a heating medium discharge passage 13 for discharging the heat medium. The rotational speed of the rotary kiln is not particularly limited but is preferably 1 to 60 rpm.

In the rotary kiln, the heating medium is supplied to the heating chamber 5 from a plurality of openings 12 provided in the heating medium supply path 11. The supplied heating medium makes one round around the rotating drum 1 along the outer periphery of the rotating drum 1 and is discharged to the outside through a plurality of openings 14 provided in the heating medium discharge path 13. Thus, the inside of the rotating drum 1 is heated by flowing the heating medium and transferring the heat of the heating medium to the rotating drum 1. On the other hand, the object to be processed is supplied into the rotary drum 1 from the supply port 6, and is transferred while stirring from the supply port 6 side to the discharge port 7 side by the rotation of the rotary drum 1. At this time, the workpiece is heated by indirect heating of the heating chamber 5, and the workpiece is carbonized. A gap 16 is provided between the metal plate 10 and the rotating drum 1 so that the metal plate 10 does not become an obstacle to the rotation of the rotating drum 1. The inner peripheral surface of the outer cylinder 4 is covered with a refractory material 15.

The carbon material obtained by the production method of the present invention can be suitably used as a main raw material coke for an anode for aluminum electrolytic production. In addition, it can also be used as a reducing carbon material for refining ferrous or non-ferrous metals, a structural carbon material, or a carbon material for electrical materials other than an anode for aluminum electrolytic production, or it can be used as a reducing carbon material or structural carbon. It can also be used as a raw material or a raw material for carbon materials for electric materials. Here, the reducing carbon material for nonferrous metal refining refers to a reducing carbon material used for refining (reducing) nonferrous metals such as silicon and titanium, and the structural carbon material includes, for example, a carbon heat insulating material, Carbonaceous material used as a raw material for carbon structural materials such as crucibles. Carbon material for electrical materials is a carbon material used as a raw material for carbon electrical materials such as carbon electrodes as well as anodes for aluminum electrolytic production. Say. Note that these materials are used because, for example, it may be necessary to subject the carbon material to a secondary treatment such as heat treatment.

As described above, the method for producing a carbon material of the present invention includes an ashless coal production step S1, an ashless coal heating step S2, a forming step S3, and a carbonization step S4. However, in carrying out the present invention, within a range that does not adversely affect the respective steps, for example, a coal pulverization step for pulverizing raw coal, or a removal step for removing unnecessary substances such as dust, before or after each step. Alternatively, other steps such as an ashless coal drying step for drying the ashless coal may be included.

Next, the Example of the manufacturing method of the carbon material concerning this invention is described concretely.
First, a slurry (1 methyl naphthalene (manufactured by Nippon Steel Chemical Co., Ltd.)) was mixed with 5 kg of Australian fuel coal (bituminous coal) in an amount of 4 times (20 kg) of solvent. This slurry was pressurized with 1.2 MPa of nitrogen and extracted in an autoclave with an internal volume of 30 L at 370 ° C. for 1 hour. This slurry was separated into a supernatant and a solid concentrate in a gravity sedimentation tank maintained at the same temperature and pressure, and the solvent was separated and recovered from the supernatant by a distillation method to obtain ashless coal.

Next, 100 g of ashless coal was put into an autoclave having an internal volume of 2 L, and heat treatment was performed in a nitrogen stream at 400 ° C. for the treatment time shown in Table 1 to obtain a modified ashless coal having the VM shown in Table 1. It was. Here, ashless coal that is not subjected to heat treatment is also modified ashless coal. Moreover, the measurement of VM was performed according to JISM8812.

This modified ashless coal is pulverized to 1 mm or less, and 3 g is filled in a mold having a cylindrical cavity having a diameter of 10 mm. The modified ashless coal filled in the cavity was molded at room temperature for 30 seconds at the molding pressure shown in Table 1 to obtain a molded body having the apparent specific gravity shown in Table 1. The apparent specific gravity was measured according to the small amount method described above.

This compact was put into a small rotary kiln and carbonized at 600 ° C. to obtain a carbon material.
About the obtained carbon material, while visually observing an external appearance, apparent specific gravity was measured according to the above-mentioned small amount method, and the following evaluation criteria evaluated.
“Appropriate” means that the appearance is massive and the apparent specific gravity is 0.5 g / cm ³ or more as a dense carbon material, and the appearance is powdery and the apparent specific gravity is less than 0.5 g / cm ³ “Not possible” because it is a carbon material. The evaluation results are shown in Table 1.

As shown in Table 1, Example No. 1 satisfying the requirements of the present invention. In Nos. 2 to 5, a dense carbon material could be obtained.
On the other hand, comparative example No. which does not satisfy the requirements of the present invention. In Nos. 1 and 6 to 8, a dense carbon material could not be obtained.

As mentioned above, although the manufacturing method of the carbon material which concerns on this invention was shown in detail, showing embodiment and an Example, the meaning of this invention is not limited to above-mentioned content, The scope of the right is a claim. It should be interpreted broadly based on the scope description. Needless to say, the contents of the present invention can be widely modified and changed based on the above description.

This application is based on a Japanese patent application (Japanese Patent Application No. 2011-046767) filed on March 3, 2011, the contents of which are incorporated herein by reference.

The carbon material of the present invention is a reducing carbon material for refining ferrous or non-ferrous metals, a structural carbon material, a carbon material for electrical materials, or a carbon material used as a raw material thereof, particularly an anode for aluminum electrolytic production. It is useful as an aggregate.

S1 Ashless coal manufacturing process
S2 Ashless coal heating process
S3 Molding process
S4 Carbonization process

Claims (3)

A reduction carbon material for refining ferrous or non-ferrous metals, a structural carbon material, a carbon material for electrical materials, or a method for producing a carbon material used as a raw material thereof,
By heating a slurry mixed with coal and solvent to extract coal components soluble in the solvent, separating the slurry after extraction into a liquid part and a non-liquid part, and separating the solvent from the liquid part An ashless coal manufacturing process for reforming coal to produce ashless coal, which is a modified coal,
An ashless coal heating step for producing a modified ashless coal having a volatile content (VM) of 40% by mass or less by heat-treating the ashless coal produced in the ashless coal production step;
Molding in which the modified ashless coal produced in the ashless coal heating step is used as a main component of the molding raw material to mold the modified ashless coal to produce a molded body having an apparent specific gravity of 0.9 g / cm ³ or more. Process,
And a carbonization step of carbonizing the molded body manufactured in the molding step to obtain a carbon material. 2. The method for producing a carbon material according to claim 1, wherein in the ashless coal heating step, the heat treatment of the ashless coal is performed in the presence of the same solvent as the solvent used for reforming the coal. . 3. The method for producing a carbon material according to claim 1, wherein in the carbonization step, the molded body is carbonized using a rotary kiln.

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