JPH05148489A - Production of pitch-based material and production of carbonaceous material with the same as raw material - Google Patents

Abstract

PURPOSE:To easily obtain a self-sinterable pitch-based material capable of giving isotropic carbonaceous materials of high density and high mechanical strength by hydrogenating pitch followed by heat treatment to regulate its softening point within a specified range and then by atomization and oxidation of the resultant pitch. CONSTITUTION:A coal-based pitch 120 deg.C in the softering point determined by mettler technique is mixed with petroleum-based residual oil, Mettler technique is mixed with petroleum-based residual oil, and an autoclave is then charged with the mixture followed by temperature raising to 420 deg.C in such a state as to maintain the pressure inside the autoclave at 5kg/cm<2>G to carry out hydrogenation. The resulting mixture is then put into a heat treatment unit where temperature is raised to 420 deg.C under a nitrogen gas stream to make a heat treatment of the mixture (pitch) to bring its softening point 5o 250-380 deg.C. The resulting pitch heat treated is atomized and then oxidized at 180-350 deg.C in an oxidative atmosphere into the objective pitch material. Thence, this material is molded into a form, which is, in turn, subjected to carbonization and graphitization, thus obtaining the other objective high-density, high-strength isotropic carbonaceous material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pitch-based material for obtaining a high-density and high-strength isotropic carbon material, and a method for producing a carbon material using such a pitch-based material as a raw material. Regarding

[0002]

2. Description of the Related Art High-density isotropic carbon materials are used as electrode materials for electric discharge machining, crucibles for aluminum vapor deposition, or wall materials for fusion reactors. In the case of producing this high-density isotropic carbon material, petroleum-based coke or coal-based coke is generally pulverized into an aggregate, and a binder is added to the aggregate to form the aggregate. Molding is usually performed using a cold isostatic press (CIP) in order to homogenize the properties. The obtained compact is 1
It is carbonized at a very slow temperature rising rate of -10 ° C / Hr, then heated to 2000-3000 ° C and subjected to graphitization treatment.

In contrast to the binary raw material using the aggregate and the binder pitch, recently, a self-sintering raw material has been developed in which one kind of particles has both the function of the filler and the function of the binder. Among them, the bulk mesophase is obtained by heat-treating petroleum-based or coal-based pitch in the range of 350 ° C to 500 ° C, and has an optically anisotropic structure (liquid crystal) fully developed. When it is used as a raw material for a high-density isotropic carbon material, it is used after being pulverized (JP-A-59-164604). Since such raw materials retain their self-sintering properties, they are fused to each other by molding, and it is not necessary to add an adhesive such as a binder.

Further, a method of using mesocarbon microbeads (MCB) as the self-sintering raw material has been proposed (JP-A-49-2379). MCB is an optically anisotropic small sphere having a minute diameter of about 10 μm which is generated during the heat treatment of various pitches. MCB
Are generated in the optically isotropic pitch matrix by heat treating the pitch. If the generated MCBs continue to be heated as they are, the MCBs coalesce to form a bulk mesophase, so the heat treatment is stopped at the stage where minute MCBs are generated, and M generated by adding a large amount of solvent.
Take out CB. However, assuming that MCB alone is insufficient in self-sinterability, a solvent is used to remove MC from the matrix pitch.
When B is taken out, it has been proposed to attach a portion mainly composed of a β component consisting of a quinoline-soluble component of the matrix pitch to the surface of MCB (JP-A-62-4170).
7).

[0005]

In the method of finely crushing coke into an aggregate and adding a binder to the aggregate to perform CIP molding, carbonization and graphitization treatment, the properties of the obtained carbon material are made uniform, Aggregate coke tends to be used with the finest grain size. However, along with this, the required amount of the binder added to bond the fine particles to each other increases. When the amount of binder added increases, the binder component decomposes and volatilizes from the molded body during the carbonization process, which reduces the residual carbon yield after the carbonization process and reduces the density of the molded body after firing. is there.

[0006] Such a tendency is similarly observed in a method in which a portion mainly composed of the β component of the matrix pitch is attached as a binder around the MCB. That is MCB
As the particle size of carbon is reduced for homogenization, it is necessary to leave a large amount of matrix pitch mainly composed of β component that serves as a binder for bonding MCBs, but the yield of carbon residue after carbonization is reduced accordingly. However, the density of the molded body after firing is reduced. Such a decrease in density corresponds to an increase in porosity, which leads to a decrease in strength.

In order to improve the above-mentioned decrease in density, that is, increase in porosity, it is often practiced to impregnate the treated body with pitch in the carbonization step or the graphitization step and reheat it. However, this method is complicated and uneconomical.

The present invention has been made in view of the above circumstances, and is a pitch-based material having self-sintering property, which makes it possible to obtain an isotropic carbon material having high density and high strength by a relatively simple process. It is an object of the present invention to provide a method for producing the above and a method for producing a carbon material using the same as a raw material.

[0009]

In order to achieve the above object, the present invention firstly hydrogenates a pitch,
Heat treatment to bring its softening point to the range of 250-380 ° C.,
Provided is a method for manufacturing a pitch-based material, which is characterized in that the pitch is further subjected to a refinement treatment and an oxidation treatment.

Secondly, there is provided a method for producing a pitch-based material, characterized in that a synthetic pitch having a softening point of 250 to 380 ° C. and having a naphthene group introduced therein is subjected to a refining treatment and an oxidation treatment.

Thirdly, a step of preparing any one of the above pitch-based materials, a step of molding the pitch-based material to obtain a molded body, and a step of carbonizing and firing the molded body to obtain a sintered body. And a step of graphitizing this sintered material, to provide a method for producing a carbon material.

As a result of earnest studies by the inventors of the present application to obtain a pitch-based material as a self-sintering raw material capable of obtaining a high-density and high-strength isotropic carbon material by a relatively simple process It has been found that a pitch-based material obtained by hydrogenating pitch, heat-treating it, then atomizing it, and further oxidizing it can be used as a raw material having self-sinterability. That is, the pitch material treated in this way has good self-sinterability and filling properties, and has a high residual coal yield during carbonization and firing. It is possible to obtain an isotropic carbon material. The present invention has been completed based on such knowledge. The present invention will be described in detail below.

The pitch raw material used for producing the pitch raw material of the present invention may be either coal-based residual oil or petroleum-based residual oil. The softening point of the pitch raw material used is 40 ° C.
The temperature is preferably 250 ° C or higher and 250 ° C or lower. If it is lower than this range, the yield of the heat-treated pitch decreases, and if it is higher than this range, the pitch raw material does not dissolve until it reaches a high temperature, so it may be mixed with a solvent or fluidized in the reactor. It becomes difficult to plan. The more preferable softening point range is 80 ° C.
~ 150 ° C.

The hydrotreatment is accomplished by holding under a hydrogen gas atmosphere, preferably at a temperature of 350 to 450 ° C. for a time of 3 hours or less. After raising the temperature to this range, the temperature may be lowered immediately without holding. At this time, a catalyst composed of Ni, Co, Mo, or the like, or red mud, sulfur, or the like may be used as the catalyst. In this case, the hydrogen gas atmosphere may be either under atmospheric pressure or under pressure, and effects corresponding to each may be obtained.

Further, in this hydrogenation treatment, a solvent which holds hydrogen which can be transferred in advance is mixed with the pitch and the temperature is adjusted to 350-
It may be held at a temperature of 450 ° C. for 3 hours or less (including the case where it is not held).

Whether hydrogen gas is used or a solvent that retains transferable hydrogen is used, sufficient hydrogen does not transfer to the pitch raw material at a temperature lower than the above range, and it transfers to the pitch at a temperature higher than this range. It is not preferable because the generated hydrogen is desorbed again.

The resulting hydrogenated pitch is further heat-treated so that its softening point is 250 ° C. or higher and 380 ° C. or lower. More preferably, the temperature is adjusted to 280 to 350 ° C. This is to improve the residual coal yield at the time of carbonization and to maintain the proper binder performance.

The pitch obtained by heat treatment in this way is atomized to a predetermined particle size. The method at this time is not particularly limited, and methods such as mechanical pulverization and atomization at high temperature can be adopted, but the particles can be made more spherical in order to improve the filling performance during molding. The method by atomization is preferable.

This finely divided pitch is subsequently subjected to an oxidation treatment. This makes it possible to obtain sufficient particle adhesion performance. This oxidation treatment may be performed in air or in an oxygen atmosphere. This oxidation treatment is 180-3
It is preferably carried out in the temperature range of 50 ° C. This is because if it is lower than this temperature, it is not sufficiently oxidized, and if it is higher than this temperature, the oxidation proceeds too much and sufficient particle adhesion performance cannot be secured. Through the above steps, a pitch-based material having desired characteristics is manufactured.

In the present invention, a pitch-based material can be obtained by using a synthetic pitch. That is, for example, a softening point in which a naphthene group is introduced in advance 250 to 380 ° C.
By using the synthetic pitch in the range of, it is possible to omit the above-mentioned hydrogenation treatment and heat treatment, and it is sufficient to perform only the steps after the atomization step. Also in this case, it is preferable to perform the oxidation treatment in the temperature range of 180 to 350 ° C. By such a method, the pitch-based material having desired characteristics can be manufactured.

As the pitch having a naphthene group introduced therein, for example, a pitch obtained by synthesizing naphthalene with a super strong acid catalyst such as HF-BF ₃ can be used.
The softening point here is the softening point obtained by the Mettler method.

The pitch-based material obtained as described above is used as a self-sintering material, molded by a known method, carbonized and fired, and graphitized to obtain a desired isotropic carbon material. can get. By manufacturing the carbon material in this manner, it is possible to achieve high density and high strength despite the relatively simple process.

[0023]

【Example】

 (Example 1)

170 parts by weight of petroleum-based FCC residual oil was mixed with 100 parts by weight of coal-based pitch having a softening point of 120 ° C. by the Mettler method. This mixture was placed in an autoclave, and the inside of the autoclave was 5 kg / cm ² 420 with G maintained
The temperature was raised to 0 ° C., and the temperature was maintained for 30 minutes for hydrotreatment. After that, all the collected samples were charged into a heat treatment apparatus, heated to 420 ° C. under a nitrogen gas flow,
The softening points were set to 270, 300, and 325 ° C., respectively, by performing heat treatment for holding at that temperature for 70, 100, and 120 minutes. The heat-treated pitch was atomized by atomization to an average particle diameter of 10 μm. The obtained fine particle pitch is 2 at each temperature of 200, 250 and 300 ° C.
Oxidation treatment was performed for 0 minutes to obtain a pitch-based material.

Next, the fine pitch-based material obtained as described above is charged into a rubber mold and 1.0 T / cm ² At CI
P-molded. This molded body is put in a carbonization furnace and the temperature is 1000 ° C.
After firing in, the temperature was further raised to 2400 ° C. in a graphitization furnace to perform graphitization treatment. The finally obtained carbon material is 50
The size was mmφ × 50 mm. The bulk density and bending strength of the obtained sample were evaluated. The results are shown in Table 1. Table 1 also shows the softening point of the heat treatment pitch and the oxidation treatment temperature.

[0026]

[Table 1] (Comparative Example 1)

A pitch having a softening point of 120 ° C. measured by the METTLER method is charged into a heat treatment apparatus, heated to 420 ° C. under a nitrogen gas flow, and heat treated by holding at that temperature for 45, 55, and 65 minutes to perform the softening point. Were heat-treated at temperatures of about 270, 300, and 325 ° C., respectively. The heat-treated pitch was atomized to have an average particle diameter of 10 μm by atomization. The fine particle pitch thus obtained was subjected to oxidation treatment at each temperature of 200, 250 and 300 ° C. for 20 minutes to obtain a pitch-based material.

Then, the fine pitch type material obtained as described above is charged into a rubber mold, and 1.0 T / cm ² At CI
P-molded. This molded body is put in a carbonization furnace and the temperature is 1000 ° C.
Then, the temperature was raised to 2400 ° C. in a graphitization furnace for graphitization. The carbon material finally obtained is 5
The size was 0 mmφ × 50 mm. The bulk density and bending strength of the obtained sample were evaluated. The results are shown in Table 2. Table 2 also shows the softening point of the heat treatment pitch and the oxidation treatment temperature.

[0029]

[Table 2]

As is clear from Tables 1 and 2, it was confirmed that in Comparative Example 1 in which no hydrogenation treatment was carried out, the bulk density was low and the bending strength was low accordingly under any conditions. It was On the other hand, in Example 1 in which the hydrogenation treatment was performed, the bulk density was higher and the bending strength was higher than that in Comparative Example. Particularly, when the oxidation treatment temperature was 250 ° C., high bending strength was exhibited. (Example 2)

50 parts by weight of petroleum-based FCC residual oil was mixed with 50 parts by weight of a pitch having a softening point of 120 ° C. by the Mettler method. This mixture was charged into an autoclave, heated to 420 ° C. under autogenous pressure, and kept at that temperature for 30 minutes. After that, all the collected samples were placed in a heat treatment apparatus, heated to 420 ° C. under a nitrogen gas flow, and heat-treated at that temperature for 85 minutes so that the softening point became about 300 ° C. The heat-treated pitch was atomized into fine particles with an average particle diameter of 10 μm by atomization. The obtained fine particle pitch was oxidized at 250 ° C. for 15 minutes to obtain a pitch-based material.

Then, the fine pitch type material obtained as described above is charged into a rubber mold, and 1.5 T / cm ² At CI
P-molded. This molded body is put in a carbonization furnace and the temperature is 1000 ° C.
After firing in, the temperature was further raised to 2200 ° C. in a graphitization furnace for graphitization. The finally obtained carbon material is 50
The size was mmφ × 50 mm. The bulk density and bending strength of the obtained sample were evaluated. The results are shown in Table 3. (Example 3)

50 parts by weight of a pitch having a softening point of 120 ° C. by the Mettler method was mixed with 50 parts by weight of petroleum FCC residual oil. This mixture was placed in an autoclave, and the inside of the autoclave was 5 kg / cm ² While maintaining G, the temperature was raised to 420 ° C. and the temperature was maintained for 30 minutes. After that, put all the collected samples into the heat treatment equipment and
The temperature was raised to 20 ° C., and a heat treatment was carried out at that temperature for 100 minutes so that the softening point became about 300 ° C. The heat-treated pitch was atomized to an average particle size of 10 μm by atomization. The obtained fine particle pitch is 2
It was oxidized at 50 ° C. for 15 minutes to obtain a pitch-based material.

Then, the fine pitch-based material obtained as described above is charged into a rubber mold and 1.5 T / cm ² At CI
P-molded. This molded body is put in a carbonization furnace and the temperature is 1000 ° C.
Then, the temperature was raised to 2200 ° C. in a graphitization furnace to perform graphitization. The carbon material finally obtained is 5
The size was 0 mmφ × 50 mm. The bulk density and bending strength of the obtained sample were evaluated. The results are shown in Table 3. (Comparative example 2)

A pitch having a softening point of 120 ° C. according to the METTLER method is charged into a heat treatment apparatus, heated to 420 ° C. under a nitrogen gas flow, and heat-treated at that temperature for 55 minutes to make the softening point about 300 ° C. Was heat-treated so that The heat-treated pitch was atomized to have an average particle diameter of 10 μm by atomization. The fine particle pitch obtained was subjected to an oxidation treatment at 250 ° C. for 15 minutes to obtain a carbon material raw material.

Next, the obtained oxidized fine particle pitch was charged into a rubber mold, and 1.5 T / cm ² Was CIP molded. This molded body was put into a carbonization treatment furnace and fired at 1000 ° C., and then further heated to 2200 ° C. in a graphitization furnace for graphitization treatment. The finally obtained product had a size of 50 mmφ × 50 mm. The bulk density and bending strength of the obtained sample were evaluated. The results obtained are shown in Table 3. Table 3 also shows the softening point of the heat treatment pitch and the oxidation treatment temperature.

[0037]

[Table 3] As shown in Table 3, in both Examples 2 and 3, the bulk density was 1.95 g / cm ^3. And a bending strength of 1000 kg / cm ² It became a high value that exceeded. On the other hand, in Comparative Example 2 in which the hydrogenation treatment was not performed, the bulk density was lower than that in the example, and the bending strength was half or less than that in the example. (Example 4)

A synthetic pitch obtained by polymerizing naphthalene using an HF / BF ₃ catalyst and having a softening point of 300 ° C. by the Mettler method was finely divided to an average particle size. The fine particle pitch thus obtained was subjected to an oxidation treatment at temperatures of 200, 250 and 300 ° C. for 15 minutes to obtain a pitch-based material.

Then, the fine pitch-based material obtained as described above is charged into a rubber mold, and 1.5 T / cm ² At CI
P-molded. This molded body is put in a carbonization furnace and the temperature is 1000 ° C.
Then, the temperature was raised to 2200 ° C. in a graphitization furnace to perform graphitization. The carbon material finally obtained is 5
The size was 0 mmφ × 50 mm. The bulk density and bending strength of the obtained sample were evaluated. The results are shown in Table 4. Table 43 also shows the softening point of the heat treatment pitch and the oxidation treatment temperature.

[0040]

[Table 4]

As is clear from Table 4, it was confirmed that the bulk density is high and a large bending strength can be obtained when the synthetic pitch has a naphthene group introduced and the softening point is within the range of the present invention. .. From the above results, the effectiveness of the present invention was confirmed.

In the above example, the petroleum FCC residual oil was used as the solvent holding the transferable hydrogen to carry out the hydrogenation treatment, but the same effect can be obtained by the hydrogenation treatment in a hydrogen gas atmosphere. I was able to do it.

[0043]

According to the present invention, there is provided a method for producing a pitch-based material having self-sinterability capable of obtaining a high-density and high-strength isotropic carbon material by a relatively simple process, and a method therefor. A method for producing a carbon material used as a raw material is provided.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C10C 3/14 6958-4H

Claims (4)

[Claims] 1. A pitch is hydrogenated and heat-treated to bring its softening point to a range of 250 to 380 ° C.
A method for producing a pitch-based material, which is characterized by further subjecting it to a refinement treatment and an oxidation treatment. 2. A method for producing a pitch-based material, characterized in that a synthetic pitch having a softening point of 250 to 380 ° C. and having a naphthene group introduced therein is subjected to a refining treatment and an oxidation treatment. 3. The oxidation treatment is performed in an oxidizing atmosphere in a range of 180 to
The method for producing a pitch-based material according to claim 1 or 2, which is performed in a temperature range of 350 ° C. 4. A step of preparing the pitch-based material according to claim 1, 2 or 3, a step of shaping the pitch-based material to obtain a shaped body, and a carbonized and fired body of the shaped body. And a step of subjecting this sintered body to a graphitization treatment, the method for producing a carbon material.