JPS58172212A - Manufacture of isotropic carbonaceous material of high density - Google Patents

Abstract

PURPOSE:To obtain a carbonaceous material of high density and high strength by carrying out oxidation and prelimiary molding between pulverization and molding stages when the heat treated product of depolymerized coal is pulverized, molded, and carbonized or graphitized. CONSTITUTION:Depolymerized coal obtd. by treating coal with a solvent under elevated pressure of hydrogen is heat treated. At this time, beta-resin which is considered to be a contributor to the caking capacity is held by an adequate amount. By holding the beta-resin, the volatile matter content is increased to cause bubbling. In order to reduce the volatile matter content, the heat treated product is finely pulverized and oxidized. The oxidation is carried out by heating to a relatively low temp. in air without requiring a long time. The oxidized heattreated product is preliminarily molded and immediately pulverized again. The fine power is molded again, and the molded body is carbonized or graphitized to obtain an isotropic carbonaceous or graphitic material of high density. Thus, bubbling during the carbonization is prevented, and the density and strength of the carbonaceous material can be increased furthermore by applying preliminary molding.

Description

DETAILED DESCRIPTION OF THE INVENTION In particular, the present invention relates to the production of isotropic high-density carbon materials and graphite materials.

Generally, petroleum-based coke is finely pulverized, molded using a binder, impregnated with pitch again after firing, and fired again. This method is an extremely complicated process.

Not only does it require a long manufacturing time.

Due to the difference in shrinkage ratio between the aggregate coke and the binder during calcination, small particles are generated, and pores are generated in the binder phase due to degassing, so the high-strength carbon material with five-sheet density is For this reason, in recent years many methods have been developed to produce strong, high-density carbon materials without using binders. For example, Carbon Magazine (m88)
According to 1. A method of extracting optically anisotropic spherules generated at the initial stage of carbonization of petroleum pitch or coal tar pitch, and molding and carbonizing them.

Alternatively, according to Wangka Ji (Volumes 72 and 73), there is a method in which coal tar pitch is heated, then oxidized with a strong oxidizing agent such as oxygen or chlorine, and then carbonized, and a molded product is pre-calcined very slowly in air. The method used is to carbonize it afterwards.

In the former method, the yield of optically anisotropic spherules as a carbon precursor from petroleum pitch or coal tar pitch as a starting material is low, and complex steps such as extraction and recovery of f# agent are required. There are drawbacks to doing so. The latter method requires a strong oxidizing agent, which makes it difficult to handle, and pre-firing the cast body in air not only requires a very long pre-firing time, but also makes it difficult to mold. It has the disadvantage that oxidation does not progress to the inside of the body and foams when carbonized.

In contrast, all conventional manufacturing methods use petroleum-based pitch or coal tar-based pitch as raw materials, so when petroleum pitch is used as raw material, the pitch properties fluctuate dramatically, and heavy metals such as Nl and V are unavoidable. It is. Furthermore, when coal tar-based pitch is used as a raw material, it is a national problem to provide a stable supply in quantity.

The present invention relates to an improved method for producing isotropic high-density carbon materials and graphite materials, which uses raw materials completely different from conventional methods and which involves relatively simple steps. The raw material in the present invention is depolymerized coal obtained by extracting coal with a solvent in a hydrogen pressurized atmosphere, deashing it, and recovering the solvent. Since the properties of the coal depolymerized product depend solely on the depolymerization conditions, regardless of the degree of coalification or other properties of the coal used as the raw material, coal of any degree of coalification can be used as the raw material. In addition, while the yield of coal tar pitch from coal is only a few centimeters, the conversion rate of coal depolymerized product from coal is nearly 100%, which makes it far superior to conventional methods. It is possible to stably supply raw materials at a much lower cost and with a higher yield. Furthermore, the coal depolymerized product is deashed to remove σ) metal content in the coal depolymerized product. Coal is even more advantageous because it contains far fewer heavy metals than petroleum-based pitch.

In addition, in conventional methods, it was difficult to control and adjust the graphitization properties of raw materials in detail, but according to Kempo, it is possible to control and adjust the carbonization properties of raw materials by selecting depolymerization conditions. Is possible.

The present inventors have completed a method for producing a forceful high-density carbon material using the above-mentioned coal depolymerized material as a raw material, which is easy to work with, has a high yield from the raw material, and has excellent graphitization properties. .

That is, the present invention provides a method for producing an isotropic high-density carbon material and a graphite material by heat-treating a coal depolymerized product obtained by solvent extraction of coal under hydrogen pressure, crushing and molding the heat-treated product, and then carbonizing and graphitizing it. isotropic, characterized in that a coal depolymerized product is heat treated, the heat treated product is pulverized, the pulverized product is oxidized, the oxide is preformed and then pulverized, and further molded, carbonized and graphitized. This is a method for producing a high-density carbon material and a graphite material.

In the conventional method, when coal-polymer is heat-treated and the heat-treated product is pulverized, molded, and further carbonized, the heat treatment conditions are stricter. Volatile content and β-797min are lower. In this case, the moldability of the heat-treated product is good, but the carbide, i.e.
The disadvantage is that the bulk specific gravity of the fired body is low. On the other hand, if the heat treatment conditions are moderate, the volatile content and β-797 content of the heat-treated product will increase, and the molded product will foam during carbonization, making firing difficult. The present inventors pulverized the heat-treated product.

By slightly oxidizing the pulverized material with air, the volatile matter and β-797 of the heat-treated material are carbonized while retaining an excessive amount of oxygen, thereby preventing foaming during carbonization and creating a high-strength, high-density, isotropic material. It has been found that a fired body can be obtained.

Furthermore, in the present invention, rather than immediately carbonizing the oxide after forming the oxide as described above, a method of preforming the oxide and then forming and carbonizing the oxide, that is, a method in which the oxide is preformed and then the formed body is finely formed. The present invention was completed based on the discovery that a carbon material with higher density and strength can be obtained by pulverizing, further molding and carbonizing the finely pulverized material.

The present invention will be described in more detail as follows.

Appropriate pulverized coal and a hydrocarbon solvent such as carbonized coal tar with a boiling point range of 200℃ to 400℃
and a distillate of 1:2 to form a slurry at a coal/solvent ratio (by weight) of about 1:1 to 1:10,
σ) The mixed slurry was heated at 300℃ under 3-300%G pressure.
Melting by heating in a temperature range of 500°C to 500°C. Hydrogen pressurization is effective for peptizing coal components into a solvent, and the coal dissolution rate is significantly improved. The heating and dissolving time is set so that the slurry has a viscosity that is sufficiently easy to filter. 6 Coal σ) After the soluble components are sufficiently dissolved, the undissolved residue is separated and removed using a filter or centrifugal separator, etc., and the filtrate is then distilled. and recover the solvent. The recovered solvent is recycled for use in this process.

The coal depolymerized product, which is the distillation residue, is used as an N material for the hygrotropic high-density carbon material.

Next, the coal depolymerized product is heat-treated. The heat treatment is performed at 300°C to 500°C, preferably 410°C to 500°C, in an atmosphere of an inert gas such as nitrogen.
The hV heat treatment is performed to generate a carbon precursor, which is further grown and developed to improve its quality.At the same time, the cracked gas and cracked oil of the heat-treated product are extracted from the system, and the volatile matter and β of the heat-treated product are extracted.
-Komabushi is 797 minutes. Volatile matter and β-797 of heat-treated products
It is preferable to have as much β-797 as possible, which is considered to contribute to caking properties, but at the same time, the volatile content becomes large and causes foaming. In other words, β-797
It is necessary to simultaneously satisfy contradictory conditions such as maximizing the amount of volatile matter as much as possible and minimizing volatile matter as much as possible. In the present invention, the volatile content is 1O~35vt, β-7
It is desirable that 97 minutes is about 1 to 50 wt%. β-797 in volatile component jiowiS
The content also becomes less than 1 wt %, and the caking within the molding disappears, making molding impossible. Further, if the volatile content exceeds 3 bwtli and the β-797min exceeds 50wtli, foaming occurs during carbonization, making it difficult to obtain a fired product. The most preferable volatile content is 15-28vt-1β-resin content is 3-28vt.
30 vt-fist Subsequently, # the heat-treated product is pulverized. At this time, the particle size is 1
00 mesh: It is desirable that it is less than L (149μ). Next, this heat-treated finely pulverized material is oxidized. Oxidation does not require strong oxidizing agents such as ozone, peroxides, or oxidants; air can be used for oxidation.
In order to carry out oxidation homogeneously and quickly, it is preferable to carry out the process in a fluidized state. For this purpose, the heat-treated material is ground into 100 mesh pieces or less and heated from room temperature to a predetermined oxidation temperature while passing air through a fluidized bed or rotary kiln. The oxidation can be carried out by holding the oxidation temperature for a predetermined time. At this time, any heating rate can be selected, but it is usually 5 to 20 degrees Celsius depending on the capacity of the equipment, etc.
A heating rate of /- is sufficient! be. Here, the oxidation temperature is t, whereas coal tar ruby polyethylene requires a long oxidation time at a high temperature of 200 °C to 300 °C or more.
'C, in the present invention, the oxidation temperature Zoo 'C ~ 280
The oxidation reaction proceeds sufficiently at a relatively low temperature of °C. This is because the coal depolymerized product, which is the raw material in the present invention, is a low-grade hydrogenolysis product, so it inherits the chemical structure of coal to the highest degree, and compared to coal tarpi, etc., which has developed fused aromatic rings. .

°This is because oxidation can be easily performed.

However, if the oxidation temperature is less than 100°C, the oxidation reaction requires a very long time, so if the temperature exceeds 280°C, the oxidation reaction will proceed rapidly and it will be difficult to control the reaction. . However, if the oxidation progresses excessively, the workability deteriorates and cracks are likely to occur during carbonization. Preferably, the oxidation temperature is 120°C to 240°C, and the oxidation time is 1-8 hr. For example, when the oxidation temperature is low, the oxidation time must be lengthened, and when the oxidation temperature is high, the oxidation time can be shortened. These conditions are determined by operability and economy. The properties of the oxide at this time include a volatile content of 12 to 27 vt% and an oxygen content of 2 to 10 wt%.
It is preferable to adjust it to 9G. Volatile content is 2
If it exceeds 7wt%, the laminated body is likely to foam during carbonization, and if it is less than 12wt%, the viscosity content also decreases, resulting in poor moldability. Similarly, the oxygen content @vt
When the oxygen content is less than $, it is considered that the oxidation reaction hardly progresses, and when the oxygen content exceeds 10 wt%, excessive oxidation occurs, resulting in a decrease in formability.

Subsequently, the oxidized heat-treated product is molded. Molding is carried out in the usual way using a rubber press, metal, etc. In the present invention, it is preferable to immediately re-pulverize the layered product after molding by a normal method. This shaping and re-grinding process is referred to by the inventors as pre-forming. However, the preliminary bottom cover of the lever is preferably formed at a molding pressure of 6 t/cd to 3 t/cd, and the inventors have found that when preforming is performed, the bulk specific gravity and strength of the fired body after carbonization are further improved. . After preforming, the finely ground material is molded again at a desired molding pressure, and the molded product is carbonized and graphitized to obtain a hygrotropic high-density carbon material and a high-strength high-density graphite material.
The carbonization temperature increase rate at t is L
6, 'C, All' to 8 Roux is desirable.

The heating rate is 8! - When the temperature exceeds -, a large rack is formed in the fired product due to rapid temperature rise. Further, if the temperature increase rate is less than ``degrees ``b''``L6'Cy-'', the sintered body will be destroyed and fall into pieces.

It is also well known that the elemental composition ratio o7c of the coal seam polymer greatly affects the properties of the carbide, but it is desirable that the 0/C of one coal seam as raw material is α040 or less. If the o7c' force of the layer polymer exceeds ζα040, the true specific gravity of the carbide becomes less than the plate, and therefore the bulk specific gravity also becomes low, so it is preferable that the O/C of the coal depolymerized product is less than 040.

The present invention will be explained in more detail below with reference to Examples.

Example 1 Australian subbituminous coal containing ash content of 1 & 7 vtfk was
Hydrogen ash in oil in 3 times the amount of tar under pressure of 60% G.

Heat at 410°C for 2 hours to dissolve solvent-soluble components.

After solid-liquid separation using a filter, vacuum distillation was performed to recover the solvent. The yield of coal depolymerized product was 6&9 vt% (daf). Moreover, the coal depolymerized horsefly is α035. This coal depolymerized product was heat treated at 430° C. for 4 hours in a nitrogen stream. The yield of the heat-treated product is 780 vt, the yield of cracked oil is 1&4 vt, and the cracked gas and loss are combined &6 vt.
It was t%. The properties of the heat treated product are volatile content 2L1 vt
%, β-resin &191. The heat-treated product was pulverized to 100 meshes or less, and further oxidized by passing air through a rotary kiln at 160° C. for 1 hour. The properties of lI2 are volatile content 1&5 wt%, WR element content 43%.
Met. Put 37 oxides into a φ cylinder and add 1
ton/j, and then the molded body was immediately re-pulverized and then put into the aforementioned cylinder again for 2 to
After forming V-, the temperature was raised to 1000°C in a nitrogen stream at a heating rate of λ3″Cy′Ik, and carbonized by holding at P1 temperature for 1 hour.The bulk specific gravity of the fired body was 564, True specific gravity L87. Porosity 123-1 Compressive strength is λ9 in the forming direction
The toV-s was 7 tors or 47'-1 in the vertical direction. The Zoo℃ fired body obtained above was further heated to 2800℃.
The properties of the graphitized product are: bulk specific gravity 190, true specific gravity λ22, porosity 144-1, and compressive strength L in the molding direction.
It was 1.5 toV- in the vertical direction of 6 tO-1.

Example 2 Australian lignite '1 containing ash content LOvt% was charged into 5 times the amount of tar oil, and iron ore (loess) containing iron oxide hydrate as a main component of 3 wt% relative to lignite was added. ) was prepared. Hydrogen pressure 100 V G pressurized 4
The mixture was heated at 20° C. for 1 hour to dissolve the solvent-soluble components, and after solid-liquid separation using a filter, vacuum distillation was performed to recover the solvent. The yield of the coal depolymerized product was 61 Ovt% (a, *-f). The coal depolymerized glue was α032. This coal depolymerized product was heat treated at 450 C for 1 hour in a nitrogen stream. The yield of heat '46 is 8!6wt%, the cracked oil yield is 1!7vt%, the cracked gas and loss is (7vt%), and the cracked oil yield is 1!7vt%.
%Met. Volatile content of heat treated portion is 2L9 vt 16
, β-regi7min is &s wt%.

The heat-treated product is pulverized to 100 mesh or less, and further pulverized to 140 mesh or less.
Air oxidation was carried out in a fluidized state by blowing air from the bottom in a cylindrical bed reactor at ℃ for 3 hours.

Volatile content of oxide is 2Q7vt, oxygen content &6wt
There was 9G. Put the oxide into a 37■φ cylinder 2
After preliminary molding at t/j, the pulverized b was further placed in the same cylinder and subjected to 4jjg & molding using 2 toams. The source material was heated at a heating rate of 3°C/- under a nitrogen stream.
The temperature was raised to 000°C and maintained at the same temperature for 1 hour. The bulk specific gravity of the obtained fired body was L66, and the true specific gravity was 187. Porosity I
The L2 arc compressive strength was @ 9 tet% cd in the molding direction and L 8 toV- in the vertical direction. 1 obtained above
When the 000°C fired body is further fired and graphitized to K 2800″C, its properties are as follows: bulk specific gravity L93, true specific gravity 122°, porosity 1 & L-1, compressive strength 7ton/cd in the molding direction.
, 1,6 taV- in the vertical direction.

Example 3 Lignite containing 1% ash was heated in 4 times the amount of oil in tar under 100% hydrogen pressure at 430°C for 1 hour to dissolve the solvent-soluble content, and after solid-liquid separation with a filter, it was heated under reduced pressure. Distillation was performed to recover the solvent. The yield of coal depolymerized product is 5 & 6
VTchi ((LIL, f) was 0.030% of the coal seam polymer was 0.030%.
After the threshold heat treatment at 450° C. for 2 hours, a further heat treatment was performed at 450° C. for 30 minutes. The yield of the heat-treated product is 7g, Ov
t%, cracked oil yield was 1&1 vt%, gas and loss was \9 vt%. The volatile content of the heat-treated product is 1 &
9 wt %, β-region 7 minutes is 6.2 vt. The heat-treated product was pulverized to 100 mesh or less. This was oxidized by circulating air in a rotary kiln at 180° C. for 20 minutes. Volatile content of oxide is 17.2
vt % - oxygen content is 41 vt 9G. After preforming this at 2 taV- using a rubber press,
It was further finely ground. This is further applied with a rubber press for 2 t.
One molding was performed again. Molded body under nitrogen stream &7
The temperature was raised to 1000"C at a heating rate of ℃/-, and the same i1&
It was baked for 11 hours. The bulk specific gravity of the obtained fired body is 14
68, true specific gravity L86. The porosity was 1α8%, and the compression strength was λ9 to− in the direction of production and Q to $cj−1i in the right direction. When this 1000℃ fired body is further fired and graphitized at 2800℃, the properties are bulk specific gravity LQ&, true specific gravity λ2
3. Porosity: 696, compressive strength: 1.7 in the molding direction
to$ad, *L6 ton/lI in the vertical direction.

Example 4 10 cases in which the heat-treated oxide of the coal depolymerized product obtained in Example 2 was subjected to a pre-molding step and in the case of normal one-time forming.
The bulk specific gravity of the 00°C fired product was destroyed, and no fired product could be obtained.

Claims (7)

[Claims] (1) A coal depolymerized product obtained by treating coal with a solvent under hydrogen pressure is heat-treated, and the heat-treated product is crushed, molded, reconstituted, and -graphitized to produce an isotropic high-density carbon material and a forceful high-density graphite material. In the method for producing isotropic high-density carbon material, the heat-treated material is pulverized, the pulverized material is oxidized, the pulverized material is preformed, and then pulverized, and further molded, carbonized, and graphitized. A method for manufacturing high-density graphite material. (2) The heat treatment temperature is 410° C. to 500° C., the heat treatment time is 1 to 12 bY, and the property of the obtained heat treated product is that the volatile content is 15 to 28 wttIb. The manufacturing method according to claim 1, wherein the β-resin content is 3 to B Ovt %. (3) The particle size of the pulverized product after heat treatment is 100 mesh (
149μ) or less, the manufacturing method according to claim 1. (4) Air is used to oxidize the pulverized material after heat treatment, the oxidation temperature is 120°C to 240°C, and the oxidation time is 1 to 8 hp.
2. The production method according to claim 1, wherein the properties of the obtained acidic substance include a volatile content of 12 to 27 wt% and an acid residue content of 2 to 1'Ovt%. (5) The manufacturing method according to claim 1, wherein the oxide is preformed at a molding pressure of L5t to 3V-. (6) Manufacturing method 0 according to claim 1, in which the temperature increase rate during carbonization is 1.5°C/- to 8°C/- (7) Claim I that the coal depolymerized product is 0 to 040 or less! 1II The manufacturing method according to item 1.