JPH1095982A - Production of carbonic microsphere - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a carbonic microsphere having optically anisotropic structure. SOLUTION: This method for producing a carbonic microsphere comprises a step for mixing an optically isotropic pitch with an optically anisotropic pitch in a weight ratio of (1:0.1) to (1:1.5), a step for stirring the mixture, if necessary by adding carbon black, at 250-400 deg.C and a step for forming and separating a carbonic microsphere consisting essentially of the optically anisotropic structure to provide the carbonic microsphere (having 0.01-500μm particle diameter). The carbonrc microsphere is, if necessary, treated in an oxidative atmosphere for thermal stabilization and thereafter fired and/or grafitized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing carbonaceous spherules. The carbonaceous spheres obtained in the present invention have a structure similar to graphite, that is, having an optically anisotropic structure,
It is rich in magnetic and chemical activity and can be widely used as a high density isotropic carbon material, high surface area activated carbon, sliding material, lubricant, chromatographic filler and the like.

[0002]

2. Description of the Related Art Japanese Patent Publication No. Sho 63-1241, Japanese Patent Publication No.
JP-A-27968 and JP-A-1-242691 disclose that a coal-based heavy oil, a petroleum-based heavy oil, or a pitch from these heavy oils is subjected to a heat treatment at a temperature of 300 to 500 ° C., and then an optical fiber formed. A production method for separating highly anisotropic carbonaceous spheres is described. Japanese Patent Publication No. 6-35581 discloses that a bulk mesophase has a viscosity of 200 to 200 times by weight in silicone oil and has a viscosity of 200.
A method for producing optically anisotropic carbonaceous spheres by performing a heat treatment at a temperature higher by 60 ° C. to 160 ° C. than the temperature at which poise is exhibited.

[0003] However, Japanese Patent Publication No. 63-1241, Japanese Patent Publication No. 27968/1988 and Japanese Patent Application Laid-Open No. 1-242991 are disclosed.
In the case of using a heavy oil as a raw material, the yield of the small spheres is only 5% by weight or less based on the raw material oil. Also when the pitch is used, the content is 10% by weight or less. In order to produce carbonaceous spheres in high yields by these methods, it is necessary to increase the heat treatment temperature or lengthen the residence time in the reactor. In this case, it is difficult to efficiently obtain carbonaceous small spheres having a size of 20 μm or less because the size of the small spheres formed by the progress of coalescence and growth of the small spheres becomes very large. Therefore, the conventional method has a problem that the production efficiency is low, the particle size of the obtained small spheres is uneven, and the surface lacks smoothness.

In the method disclosed in Japanese Patent Publication No. 6-35581, when a solid bulk mesophase is used, the bulk mesophase needs to be ground to a predetermined particle size in advance, which is complicated in operation. Further, the heat treatment requires as much as 50 to 1000% by weight of silicon oil per the bulk mesophase of the powder, and there is a problem in terms of economical efficiency because the equipment is large and the heat capacity is large.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances of the prior art, and proposes a method for efficiently producing carbonaceous spheres having an optically anisotropic structure.

[0006]

According to the present invention, an optically isotropic pitch and an optically anisotropic pitch are used in a weight ratio of 1: 0.1 to 1: 0.1.
1.5 parts by weight (if necessary, 0.1 to 30 parts by weight, preferably 0.1 to 10 parts by weight of carbon black is added to 100 parts by weight of the obtained mixture) Stirring at a temperature of 250 to 400 ° C. to form carbonaceous spheres mainly composed of an optically anisotropic structure, and then separating the spheres. Is 0.01 to 500 μm). The present invention is characterized in that the carbonaceous spheres obtained by the method are calcined and / or graphitized (after, if necessary, heat-stabilized in an oxidizing atmosphere) to produce carbonaceous spheres. In the way.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The generation and separation of carbonaceous microspheres The optically isotropic pitch and the optically anisotropic pitch are as follows:
Any of synthetic pitch, coal pitch and petroleum pitch prepared by treating an aromatic compound such as naphthalene or methylnaphthalene with an acid catalyst or the like can be used. In a preferred embodiment, an optically isotropic synthetic pitch and an optically anisotropic synthetic pitch are used in terms of structural similarity, solubility and viscosity. The optically isotropic pitch and the optically anisotropic pitch can be mixed in any of solid-solid, liquid-solid and liquid-liquid systems.

The optically isotropic pitch is a pitch mainly composed of an optically isotropic structure, and is a pitch showing an isotropic structure by observation with a polarizing microscope. The optically anisotropic pitch is a pitch mainly composed of an optically anisotropic structure, and is a pitch showing an anisotropic structure by observation with a polarizing microscope.

By heating the mixed pitch, carbonaceous small spheres can be efficiently produced. By heat-treating the mixture pitch, a part of the structure of the optically anisotropic pitch undergoes a change in the arrangement to become an optically isotropic pitch, and the part of the optically anisotropic structure in which no rearrangement occurs occurs in a solvent. It disperses in the optically isotropic pitch as carbonaceous small spheres that do not dissolve in the like, and becomes carbonaceous small spheres.

A mixture (mixed pitch) obtained by mixing an optically isotropic pitch and an optically anisotropic pitch is heated,
By stirring at a temperature of 250 to 400 ° C., carbonaceous spheres mainly composed of an optically anisotropic structure are easily formed. The mixing pitch can be heated in an atmosphere of an active gas such as air, but it is safer to heat the mixture pitch in an atmosphere of an inert gas such as nitrogen or argon. Regarding the mixing pitch, carbonaceous spheres can be generated by heating under normal pressure or under pressure.

By heating, melting and stirring the mixed pitch, the optically anisotropic pitch and the optically isotropic pitch can be well dispersed. The mixing pitch can be agitated by any method such as a method using a stirring blade, a method using a homogenizer, and a liquid circulation jet flow method. By stirring for about 5 to 120 minutes while heating the mixing pitch, carbonaceous small spheres can be efficiently generated. If heating and stirring of the mixed pitch are performed for an excessively long period of time, the anisotropic pitch rearrangement causes the anisotropic organization to proceed, so that the particle size of the generated carbonaceous small spheres increases.

In a preferred embodiment, the particle size is 0.01
A carbonaceous spheroid having a size of about 500 μm and, if necessary, about 0.01 to 20 μm is produced. By adjusting the mixing ratio of the optically isotropic pitch and the optically anisotropic pitch, the conditions of the heat treatment and the stirring conditions, and / or adding 0.1 to 30% by weight of carbon plaque to the mixed pitch. The particle size of the resulting carbonaceous spheres can be easily controlled.

The formed carbonaceous spheres can be obtained by a conventional high-temperature centrifugation method, an anti-solvent method, a critical extraction method, an extraction method using a general solvent such as quinoline or toluene, or a filtration method. By this, it is possible to separate from the isotropic pitch. The isotropic pitch remaining after separating the carbonaceous spheres can be reused as the isotropic pitch used for the raw material, and is economically advantageous.

Firing and graphitizing the carbonaceous spheres By firing and / or graphitizing the separated carbonaceous spheres, carbonized or graphitized carbonaceous spheres can be produced. By baking the carbonaceous spheres at a temperature of about 600 to 2000 ° C. in a non-oxidizing atmosphere, for example, in a nitrogen gas atmosphere, in an argon gas atmosphere,
Carbonized carbonaceous spherules can be produced. By sintering the carbonaceous spheres or carbonized carbonaceous spheres in a non-oxidizing atmosphere, for example, in a nitrogen gas atmosphere or an argon gas atmosphere at a temperature of about 2000 to 3500 ° C., the graphitized carbonaceous Spheres can be manufactured.

By subjecting the carbonaceous spheres before firing or graphitization to a thermal stabilization treatment in an oxidizing atmosphere, it is possible to prevent the carbonaceous spheres from fusing during firing or graphitization. Under an oxidizing atmosphere, for example, in the atmosphere,
50 to 400 ° C in an oxygen-nitrogen mixed gas atmosphere or the like
Heat stabilization can be performed by heating at a temperature of about the same. By the heat stabilization treatment, an oxide film can be formed on the surface of the carbonaceous spheres, and the carbonaceous spheres can be prevented from melting and adhering to each other during firing or graphitization.

[0016]

According to the present invention, carbonaceous spheres having a uniform particle size and a smooth surface can be efficiently produced. According to the present invention, the amount of free carbon, the amount of hetero compounds (oxygen, sulfur, nitrogen, etc.) and the amount of metal components in the carbonaceous spheres can be controlled by selecting the raw material pitch. According to the present invention, a carbonaceous small sphere can be efficiently produced by mixing an optically isotropic pitch and an optically anisotropic pitch, stirring with heating, and separating the generated small sphere. .
Therefore, the present invention has a great economic effect as compared with the conventional method.

[0017]

EXAMPLE 1 Table optically isotropic shown in one pitch A and (300 g) and optically anisotropic pitch C (200 g) were charged to a 1 liter autoclave, heating rate in a nitrogen atmosphere under normal pressure 2
The pitch was heated at 360 ° C./min. At this time, stirring was gradually started using an anchor-type stirring blade from the time when the pitch was melted.

When the pitch temperature reached 360 ° C., the stirring speed was further increased to 1200 rpm, and a treatment was carried out for 30 minutes while stirring, and the pitch was cooled and taken out. As a result of extracting this pitch with pyridine, carbonaceous spheres having an optically anisotropic structure were obtained at a ratio of 16% by weight based on the total pitch amount used. The average particle size of the carbonaceous spheres was 18 μm.

Example 2 (Effect of mixing ratio of raw materials) An optically isotropic pitch A (200 g) and an optically anisotropic pitch C (300 g) shown in Table 1 were charged into a 1-liter autoclave, and nitrogen atmosphere was used. Heating rate 2 under normal pressure
The pitch was heated at 360 ° C./min. At this time, stirring was gradually started using an anchor-type stirring blade from the time when the pitch was melted.

After the pitch temperature reached 360 ° C., the stirring speed was further increased to 1200 rpm, a treatment was carried out for 30 minutes while stirring, and the pitch was cooled and taken out. As a result of extracting the pitch with pyridine, carbonaceous spheres having an optically anisotropic structure were obtained at a ratio of 27% by weight based on the total pitch amount used. The average particle size of these carbon globules is
It was 27 μm.

Comparative Example 1 (Effect of Mixing Ratio of Raw Materials) Optically isotropic pitch A (150 g (1 part by weight)) and optically anisotropic pitch C (350 g (about 2.3 parts by weight)) shown in Table 1 ) Was charged into a 1-liter autoclave, and the same experiment as in Example 2 was performed. As a result, it was confirmed that carbonaceous spheres having an optically isotropic structure but not an optically anisotropic structure were generated.

Example 3 (Effect of Stirring Rotation Speed) An optically isotropic pitch A (300 g) and an optically anisotropic pitch C (200 g) shown in Table 1 were charged into a 1-liter autoclave, and a nitrogen atmosphere was used. Heating rate 2 under normal pressure
The pitch was heated at 360 ° C./min. At this time, stirring was gradually started using an anchor-type stirring blade from the time when the pitch was melted.

When the pitch temperature reached 360 ° C., the stirring speed was further increased to 4000 rpm, and a treatment was carried out for 30 minutes while stirring, and the pitch was cooled and taken out. As a result of extracting this pitch with pyridine, carbonaceous spheres having an optically anisotropic structure were obtained at a ratio of 17% by weight based on the total pitch amount used. The average particle size of the carbonaceous spherules was 13 μm.

Example 4 (Effect of Raw Material Type) An optically isotropic pitch B (300 g) and an optically anisotropic pitch D (200 g) shown in Table 1 were charged into a 1-liter autoclave, and the mixture was placed in a nitrogen atmosphere at normal pressure. At a heating rate of 2
The pitch was heated at 340 ° C. by heating at a rate of ° C./min. Less than,
By the same operation as in Example 1, carbonaceous small spheres were obtained. The average particle size of the obtained carbonaceous spheres was 16 μm, and the yield per pitch used was 16% by weight.

Example 5 (Effect of Addition of Carbon Black) An optically isotropic pitch B (300 g) and an optically anisotropic pitch C (200 g) shown in Table 1 were charged into a 1-liter autoclave, and further, carbon black was added. (5 g) was added thereto, and the mixture was heated at a heating rate of 2 ° C./min under a normal pressure in a nitrogen atmosphere to adjust the pitch temperature to 380 ° C. Thereafter, carbonaceous small spheres were obtained by the same operation as in Example 1. The average pitch particle size of the obtained pitch spheres was 12 μm, and the yield per pitch used was 21% by weight.

Comparative Example 2 An optically isotropic pitch A (500 g) shown in Table 1 was charged into a 1 liter autoclave and heat-treated at 380 ° C. for 2 hours in a nitrogen atmosphere to produce small spheres. Thereafter, carbonaceous spheres were separated by the same operation as in Example 1.
The average particle size of the obtained carbonaceous microspheres was 22 μm, and the yield per pitch used was 1% by weight. In addition, the small spheres had a non-uniform particle size distribution and included irregular shapes.

Comparative Example 3 An optically isotropic pitch A (500 g) shown in Table 1 was charged into a 1-liter autoclave and heat-treated at 380 ° C. for 6 hours in a nitrogen atmosphere to produce small spheres. Thereafter, carbonaceous spheres were separated by the same operation as in Example 1.
The average particle size of the obtained carbonaceous microspheres was 35 μm, and the yield per pitch used was 5% by weight. In addition, the small spheres had a non-uniform particle size distribution and included irregular shapes.

[0028]

Table 1 Softening point (° C) BS BI-PS PI H / C Optically isotropic pitch A 165 70 273 3 0.69 Optically isotropic pitch B 170 69 274 4 0.70 Optical anisotropy Pitch C 237 46 21 33 0.65 Optically anisotropic pitch D 227 41 27 32 0.65

Remarks) The isotropic pitches A and B and the anisotropic pitch C are pitches using naphthalene as a raw material, and the anisotropic pitch D is a pitch using methylnaphthalene as a raw material. BS indicates the amount of benzene-soluble components (% by weight).
BI-PS shows the amount (% by weight) of a component dissolved in pyridine and insoluble in benzene. PI indicates the amount (% by weight) of a component insoluble in pyridine.

Claims (5)

[Claims] 1. An optically isotropic pitch and an optically anisotropic pitch are mixed at a weight ratio of 1: 0.1 to 1.5, and stirred at a temperature of 250 to 400 ° C. A method for producing carbonaceous small spheres, comprising generating carbonaceous small spheres mainly composed of an optically anisotropic structure, and separating the small spheres. 2. An optically isotropic pitch and an optically anisotropic pitch are mixed at a weight ratio of 1: 0.1 to 1.5, based on 100 parts by weight of the obtained mixture. 0.1-3
0 parts by weight of carbon black, 250 to 400
A method for producing carbonaceous spheres, comprising: producing carbonaceous spheres mainly composed of an optically anisotropic structure by stirring at a temperature of ° C .; and separating the spheres. 3. The carbonaceous small spheres have a particle size of 0.01 to 500.
The method for producing carbonaceous spherules according to claim 1 or 2, which has a size of µm. 4. A method for producing carbonaceous spheres, comprising firing and / or graphitizing the carbonaceous spheres obtained by the method according to claim 1. 5. A carbonaceous spheroid obtained by the method according to claim 1, which is heat-stabilized in an oxidizing atmosphere, and then calcined and / or graphitized. A method for producing carbonaceous spheres.