JPS6024042B2 - Method for producing easily graphitizable carbon material raw material - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing a graphitizable carbon material raw material.

Specifically, the present invention relates to a method for producing a graphitizable carbon material raw material by heat-treating a hydrogenated liquefied product of ordinary coal. Artificial graphite and carbon materials for electrodes for aluminum refining have low ash, sulfur, and oxygen content, high true specific gravity, and good orientation.
Good graphitizability is an essential condition.

When non-semi-occupied silk thermal coal is hydrogenated in the presence of a solvent, a certain amount of sulfur and oxygen are removed from the raw coal, and when this is passed through a sandpaper and the solvent is recovered, a clean pitch-like substance is produced. known to be obtained. However, the carbonization properties of this liquefied demineralized product vary depending on the type of raw coal and the hydrogenation conditions. The selection of the coal type and hydrogenation conditions is subject to the need to maximize the yield of the desired hydrogenated extract and operational constraints, so not all liquefied demineralized materials are used in the production of carbon material raw materials for electrodes. It cannot be said that it has properties suitable for. The liquefied demineralized material produced under normal conditions has a higher degree of substitution than normal high-temperature carbonized tar pitch and is inferior in aromaticity, resulting in extremely high thermal reactivity and a narrow softening and melting range. Therefore, as a carbon material raw material, it has poor orientation and graphitization properties, and is insufficient as a high-quality carbon material for electrodes. The purpose of the present invention is to treat such a hydrogenated liquefied product with a high degree of substitution and poor aromaticity to reduce the ash content, sulfur content to 0,
It is an object of the present invention to provide a method for producing a carbon material raw material having a significantly low oxygen content and excellent oriented graphitization properties.

As a result of research, the inventors of the present application have found that hydrogenated liquefied products with a high degree of substitution and poor aromaticity can be used under pressure of 350 to 500% in the coexistence of a solvent.
It has been discovered that heat treatment at a temperature of 0:00 for several hours can yield a carbon material raw material with extremely low ash content, sulfur content, and oxygen content (excellent oriented graphitization properties). The necessary heat treatment conditions vary depending on the coking coal and hydrogenation conditions, but are usually 35
If the temperature is below 0qC, sufficient modification will not take place. (In this heat treatment reaction, the desorption phenomenon of oxygen in the 0-liquefied product due to the formation of water is noticeable, but it is slow below 350°C.) On the other hand, when the temperature exceeds 500°C, the reaction is rapidly accelerated and a pitch with a high softening point is formed. Furthermore, it was found that complete coke formation occurred. Furthermore, during heat treatment, components that are highly reactive and easily turn into coke undergo polycondensation to produce quinoline insoluble matter (hereinafter abbreviated as QI) that does not dissolve in the matrix, but as the heat treatment progresses further, it forms large solid particles. Precipitates in pitch-like substances.

Therefore, the ash and oxygen content in the hydrogenated liquefied product are concentrated in such QI fine particles and solid particles, and it is believed that the improvement effect of thermal reforming will be increased by removing these particles. I found it. Therefore, this heat treatment under pressure has an improvement effect in the normal coal hydrogenation and liquefaction process, hydrogenation → Kashiwak → solvent recovery, either before or after Kashi-filtration, but the precipitated Q1, In order to remove solid particles by an economical one-time sieving operation and to further enhance the effect, it is preferable to carry out the heat treatment before deashing the hydrogenated liquefied product.

In the heat treatment carried out after filtration, in the coexistence of a solvent or
To some extent, it is possible to use medium pitch with recovered solvent.

In addition, the heat treatment performed before filtration must be carried out in the presence of a solvent in order to facilitate the filtration that is to be carried out later.

Therefore, when heat treatment is performed before passing through, the heat treatment conditions are slightly more severe than when heat treatment is performed after passing through. As described above, the present invention is based on the conventional coal hydrogenation and liquefaction process, hydrogenation→transition→
During solvent recovery, heat treatment (350 to 500 qo for several hours) under appropriate pressure is performed before or after wave filtration (heat treatment conditions can be relaxed by using a catalyst) to produce raw materials for graphitizable carbon materials for electrodes. This is what I am trying to do.

FIG. 1 is a process flow sheet showing a comparison between the method of the present invention and a conventional method. This is the case of the heat treatment before filtration in the method of the present invention.

In the figure, R, F, S and day indicate the steps of hydrogenation liquefaction reaction, filtration, solvent recovery, and heat treatment, respectively, a indicates unreacted matter, ash content, and solid matter, and p indicates the carbon material raw material of the product. shows.

Next, the present invention will be explained with reference to examples.

In addition, in the tables in the examples, SP (Hg) is the softening point of pitch determined by the mercury method; BI is the benzene-insoluble content, i.e., the residual amount after benzene extraction; FC is the fixed carbon, i.e., in an inert atmosphere. This is the residual carbon content after firing at a specified temperature.

Also, Lc (002) is the size of the crystallite, Co (002)
is an X-ray parameter indicating the degree of crystallinity in terms of lattice number, and is obtained by measuring the diffraction intensity of the (002) plane of graphite.

In other words, Lc indicates the degree of stacking of benzene layers,
Co indicates the degree of spacing between benzene layers. Example
1 K coal with twice the amount of anthracene oil at 100 k hydrogen pressure
9/ Pitch whose softening point was adjusted to 94.1°C by partially recovering the solvent from the pitch obtained by deashing after hydrogenation under the condition of a ground temperature of 430 qo, and a pitch whose softening point after deashing was adjusted to 60.000. The adjusted medium pitch is 430qo and 1. Heat treatment was performed under nitrogen pressure for a beat time of 20 k9/hr, the softening point was adjusted to 92.8 qo, and the properties, carbonization, and graphitization of the heat-treated pitches were compared.

(See Table 1 and Figures 2 and 3) Compared to untreated pitch, heat-treated pitch has a larger carbon content and lower sulfur, oxygen, and ash content, and is also superior in carbide orientation and graphiticity.

Furthermore, according to the flow rate measurement by Giesler, the flow range was wider at 440 qo compared to 390 oo for the untreated pitch, and the pitch was suitable as a raw material for carbon material for electrodes. The solid material precipitated in this example was significantly enriched in ash, sulfur, and oxygen compared to untreated pitch. Table 1 Properties of K coal pitch, carbonizability, graphitizability * Observation of 600℃ carbonized product with polarized light microscope * * 26
Example of X-ray measurement of 00℃ graphitized material based on the Gakusaru method 2 Coal B was heated to 70k9 hydrogen pressure with twice the amount of anthracene oil.
The material obtained by deashing after hydrogenation at a soil temperature of 430°C was recovered as a solvent and the softening point was adjusted to 93.0°C. After deashing, pitch adjusted to have a saponification point of 0 qo and medium pitch adjusted to a saponification point of 60.0 qo were thermally modified at a temperature of 42,000 for 6 hours under nitrogen pressure of 20 k9/gold to bring the softening point to 95.0 qo. The properties, carbonization properties, and graphitization properties of the heat-treated pitches adjusted to 0oo were compared.

(See Table 2 and Figures 4 and 5) Heat-treated pitch has a larger C day than untreated pitch;
It was a carbon material raw material with low ash content and excellent orientation and graphitization properties.

Table 2 B Properties of Charcoal Pitch, Carbonizability, Graphite A* Observation of 600°C carbonized product using a polarizing microscope 4** 2
Example of X-ray measurement of 600℃ graphitized material based on the Gakuaya method
3 For the B coal hydrogenated with twice the amount of anthracene oil in a pressurized vessel under the conditions of an initial hydrogen pressure of 100 kg/, a temperature of 400 oo, and a reaction time of 1 hour, (1) After deashing, some of the solvent was recovered. Pitch A (0
) After deashing, some of the solvent was recovered and the softening point was adjusted to 60.0qo, and the medium pitch was heated at a temperature of 42,000°C for 3 hours at 20k9/
Heat treatment was carried out under nitrogen pressure in the air, and Satoshi. Pitch B (m) with softening point adjusted to 0℃ 4 in the coexistence of solvent prior to deashing
Heat treatment was carried out at a temperature of 30 qo for 3 hours under a nitrogen pressure of 30 k9/g, and the produced solids were filtered together with the ash,
Thereafter, the properties, carbonization properties, and graphitization properties of three types of pitches, including pitch C whose softening point was adjusted to 99.3 qo, were compared.

(Refer to Table 3 and Figures 6, 7, and 8) The flow range of the pitch at this time is based on the results of the Gissler test, which indicates that the pitch is A369.
oo, pitch B41 was o, and pitch C424q○.

The carbonization and graphitization properties of the pitches were excellent in the order of A<B<C, and pitches B and C were pitches suitable as a raw material for coke for electrodes.

Table 3 Properties of B Charcoal Pitch, Carbonization, Graphitization* Observation of 500℃ carbonized product with polarized light microscope** 260
X-ray measurement of graphitized material at 0°C based on the Gakushin method.The present invention shows that liquefied demineralized material, which has poor orientation and poor graphitization properties, can be easily heat-treated as a raw material for conventional electrode coke. Through these operations, it is possible to improve the carbon material raw material with excellent orientation and graphitization properties, making it possible to produce high-quality electrode coke.Moreover, this improvement can be achieved by removing the quinoline residue that precipitates during heat treatment. In order to increase the effectiveness, the high-temperature liquefied product discharged from the hydrogenation reaction tank in the normal hydrogenation process (hydrogenation → filtration → solvent recovery) is directly led to the next heat treatment tank to carry out a thermal reaction. If the quinoline insoluble matter produced in the reaction is removed together with the ash by the ash, it becomes possible to further improve the liquefied demineralized material in an extremely economical manner.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the manufacturing process of graphitizable carbon material raw material according to the present invention and the conventional manufacturing process. -It is a sheet. 2 and 3 are polarized light micrographs of carbonized and fired products of untreated pitch and heat-treated pitch, respectively, in Example 1;
Figures 6, 7, and 8 are polarized light micrographs of carbonized and fired products of pitch A, pitch B, and pitch C, respectively, in Example 3. . Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. A hydrogenated liquefied product obtained by hydrogenating non-caking coal is heat treated at a temperature of 350 to 500°C under pressure in the coexistence of a solvent for several hours, and the quinoline insoluble matter generated is filtrated together with the ash. 1. A method for producing a graphitizable carbon material raw material, which comprises removing the graphitizable carbon material by removing the carbon material.