KR960008619B1 - Process for the preparation of high density carbon material - Google Patents

Abstract

The raw material of this carbon material is coal tar pitch gained by drying coal tar produced as a by product in the process of manufacturing cokes for making steel or city gas. The carbon material is produced by the processes of (1) manufacturing coal tar pitch at melting point of 62 to 72deg.C, (2) manufacturing of coal tar pitch residue of 2.4 to 5.3wt.% Ù-resin by heating to 480 to 520deg.C at the heating rate of 5 to 10deg.C, and by dry heat-treatment of coal tar pitch under inert atmosphere for 1 to 2 hours at 480 to 520deg.C, (3) dry and wet crushing the residue to the average particle size of up to 120 Pm by dry crushing, and then to the size of 2 to 5 Pm by wet attritor crushing, and removing wetting water, (4) compacting by an ordinary method, and (5) carbonizing treatment of green compaction at 1,000 to 1,200deg.C for 1 to 2 hours. This produced carbon material is used for machine past such at bearing, mechanical sealing, packing, brake disc, dies, molding board, graphite roller, etc. and for heat resisting material of graphite crucible, mold, evaporation boat, etc.

Description

Manufacturing method of high density carbon material with excellent mechanical properties

1 is a manufacturing process diagram of a high-density carbon material by a conventional method,

2 is a manufacturing process diagram of a high density carbon material by a conventional Chinese New Year method,

3 is a manufacturing process diagram of a high density carbon material according to the present invention,

4 is a graph showing the change in the average particle size of the crushed coke according to the operating time of the attritor crusher when crushing the coke according to the present invention,

5 is a photograph of a molded and carbonized molded body according to the present invention.

The present invention relates to a method for manufacturing high-density carbon materials used in mechanical materials such as bearings, mechanical seals, packings, brake discs, dices, plates, graphite rolls, and heat-resistant materials such as graphite crucibles, molds, evaporation boats, and rods. More specifically, a patent application for a method for producing a high density carbon material using coal tar pitch obtained by distilling coal tar generated as a by-product when remaking steel coke or city gas from coal raw materials. It relates to an improved invention of patent application No. 92-2307.

As a conventional method of manufacturing a carbon material used for the above uses, a two-way method is used. As shown in FIG. 1, this two-way method is an aggregate of various carbon or graphite aggregates. Pulverized to an appropriate particle size, sieving the pulverized aggregate and blending the particle size, and then added a binder such as coal tar pitch and coal tar, kneaded and press-molded to obtain a particle carbonaceous plastic at a temperature of about 1000 ° C. In order to produce a carbonaceous material or to increase the density of the primary carbonized calcined body, impregnating the molten coalta or the melt of the coal tar pitch to fill in the minute processing generated from the primary hydrocarbon, and then repeating the secondary calcining process repeatedly. The method of manufacturing a high density carbon material by performing a post-graphitization process is known.

However, in the above-described binary method, not only the strict quality control and enormous energy consumption are required to prevent expansion or cracking but also the density of the manufactured carbon material is only 1.55-1.64 g / cm 2.

Recently, a method of producing a high-density carbonaceous and graphite material by a method different from the above-described method has been proposed, and the representative method is a one-way method. It is a method that can greatly omit manufacturing processes such as crushing, blending, mixing, forming, primary firing, impregnation, secondary firing and graphitization without using the binder in a separated state, using coal tar or coal tar pitch as a raw material. A method of producing a so-called self-crystallized carbonaceous material which is subjected to dry distillation and contains a binder in itself can be cited. One of the industrialized methods among these methods is the Chinese New Year method shown in FIG. have.

The method of FIG. 2 is a mesophase micro sphere having a diameter of 3-15 μm, commonly referred to as a spherical sphere, produced in the range of 350-450 ° C. in the process of heating and distilling coal tar or coal tar pitch. ) Is separated by solvent extraction to form a spherical powder containing a suitable binder component and carbonized and graphitized by heat treatment. Yamada, K.Shibata, E. Honda, S. ohi: Carbon No. 88, 2 (1977)]

However, since the process of manufacturing the Chinese New Year is complicated and the yield of spherical body obtainable from coal tar pitch is less than 10% and is very expensive, it is not used except for some special materials.

Accordingly, the present inventors have conducted research and experiments on the one-way method, and based on the results, the present inventors can use the entire amount of carbon contained in the coal tar pitch, so that the yield is high, the manufacturing process is simple, and the energy consumption is less economical. It proposed a manufacturing method of high-density carbon material and filed a patent in Korea on February 17, 1992 (Patent Application No. 92-2307).

The patent application No. 92-2307 is to dry coal coal to produce a coal tar pitch having a melting point of 62-72 ℃; The coal tar pitch was heated to 480-520 ° C. in an inert atmosphere at a temperature increase rate of 5-10 ° C./min, and subjected to dry distillation heat treatment maintained at this temperature for 1-2 hours to test the tar pitch of JIS K 2425. Preparing a coal tar pitch residue (self-sintering coke) containing 2.4-5.3 wt% of β-resin, which is defined as the insoluble content minus Quinoline insolubles; Grinding the coal tar pitch residue to have an average particle size of 2.5-5 μm; Molding the coal tar pitch residue pulverized as described above in a conventional method; And carbonizing the molded body of the coal tar pitch residue molded as described above at a temperature range of 1000-1200 ° C. to produce a carbonaceous material, or firing the carbonized fired body at a temperature of 2000 ° C. or higher. The manufacturing method of the high-density carbon material comprised including the step of graphitizing and manufacturing a graphite material is made into the summary.

The present inventor has studied the above-mentioned patent application No. 92-2307, and proposed the present invention based on the results, and the present invention improves the quality of the coal tar pitch residue by improving the grinding step. To provide a more economical way to produce a carbon material of, there is a purpose.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention comprises the steps of carbonizing the coal tar to produce a coal tar pitch having a melting point of 62-72 ℃; The coal tar pitch was heated to 480-520 ° C. in an inert atmosphere at a temperature increase rate of 5-10 ° C./min, and subjected to a dry distillation heat treatment maintained at this temperature for 1-2 hours to test the tar pitch of JIS K 2425. Preparing a coal tar pitch residue (self-sintering kosk) containing 2.4-5.3 wt% of β-resin, which is defined as the insoluble content minus Quinoline insolubles; Removing the adhering water for pulverizing the coal tar pitch residue; Molding the coal tar pitch residue pulverized as described above in a conventional method; And carbonizing the molded body of the coal tar pitch residue molded as described above at a temperature range of 1000-1200 ° C. to produce a carbonaceous material, or firing the carbonized fired body at a temperature of 2000 ° C. or higher. In the method for producing a high density carbon material comprising the step of graphitizing to produce a graphite material, the grinding step of the coal tar pitch residue is composed of a dry grinding process and a wet grinding process; In the dry grinding step, the crude grinding is performed such that the average particle diameter of the coal tar pitch residue is 120 µm or less; In the wet grinding process, the average particle diameter of the coal tar pitch residue is 2.5 μm in an attritor grinder including a grinding container with tungsten carbide, a tungsten carbide rotating shaft, and a tungsten carbide bowl. A high density carbonaceous material having excellent mechanical properties can be obtained by grinding the tungsten carbide having a thickness of 2-5 μm to 1.0 wt% or less, preferably 0.2-0.5 wt%, by wear of the constituent members by tungsten carbide balls of the lighter grinder. It relates to a manufacturing method.

Hereinafter, the present invention will be described in detail with reference to FIG. 3.

In the present invention, as shown in FIG. 3, coal tar is carbonized to obtain a coal tar pitch having a melting point of 62-72 ° C, and the coal tar pitch is used as a starting material.

The coal tar pitch obtained as described above was placed in a heat resistant reaction vessel, and heated to 480-520 ° C. at an elevated temperature rate of 5-10 ° C./min in an inert atmosphere, followed by dry heat treatment for 1-2 hours. After cooling naturally.

If the maximum temperature rises outside the 480-520 ℃ or the holding time is more than 1-2 hours, the maximum temperature rises to 480-520 ℃, holding time because the cracking or low density during molding and / and firing 1-2 hours is preferable.

While heating the coal tar pitch, argon gas or N ₂ gas is blown into the reaction vessel by an inert gas by a stainless pipe or the like. This is to eliminate the temperature deviation and to promote the polycondensation reaction of the pitch by stirring the inert gas.

Useful volatiles generated during dry heat treatment are cooled and recovered.

As described above, by heating the coal tar pitch to 480-520 ° C. and maintaining it at this temperature for 1-2 hours, the melt pitch gradually becomes viscous to move from the semi-solid to the solid. In the present invention, tar pitch of JIS K 2425 is used. According to the test method, it is required to maintain an appropriate amount of β-resin in the residual residue, which is defined as minus Quinoline insolubles from Toluene insolubles.

When the residual amount of β-resin is too small, cracking occurs during sintering of carbon, and when the residual amount is too large, expansion occurs during sintering of carbon. Thus, the residual amount of β-resin in the present invention is 2.4-5.3wt. It is desirable to limit to%.

As described above, the dry distillation residue of the self-crystallized coal tar pitch containing 2.4-5.3 wt% of β-resin is obtained by dry heat treatment.

The residue obtained by the dry distillation heat treatment is naturally cooled, taken out of the reactor and then ground.

In the present invention, the coal tar pitch residue may be pulverized by a dry grinding process and a wet grinding process. In the dry grinding process, an average particle diameter of the coal tar pitch residue may be 120 μm using a grinder such as a ceramic ball mill. It is coarsely pulverized to

In the wet grinding process, an attritor grinder is used, and the grinder includes a grinding vessel having a tungsten carbide inside, a tungsten carbide rotating shaft, and a tungsten carbide bowl.

The rotating shaft is attached to a plurality of branches, the size of the bowl is changed depending on the capacity of the attritor, the diameter is preferably about 5mm.

Coal tar pitch residues pulverized in the dry grinding process are loaded into an attritor grinder and pulverized to have an average particle diameter of 2-5 µm. In this grinding process, tungsten of the constituent members of the attritor grinder is removed by a bowl. Carbide wears into the coal tar pitch residue.

At this time, the wear amount by the tungsten carbide bowl can be expressed as in the following formula (1).

F = K (R × T × B) ........................ ....................(One)

(Where R: wear amount (mg), R: rotational speed (R.P.M), T: grinding time (hr), B: weight of bowl (kg), and K: constant determined experimentally))

The amount of tungsten carbide added after wear is 1.0 wt% or less, preferably 0.2-0.5 wt%, because when the amount of tungsten carbide is 1.0 wt% or more, it is not good in terms of brittleness and tensile strength. to be.

It is preferable to grind so that the average particle size of a residue may be 2.0-5 micrometers in the said grinding | pulverization process, since the cost increases when an average particle size is 2.0 micrometers or less, and when it is 5 micrometers or more, a density becomes low.

In addition, it is preferable to limit the average particle diameter of the added tungsten carbide to 2.0-5.0 μm, although the reason is possible even when the average particle size is 2 μm or less. It is because when it is more than a micrometer, a density will fall and a minute hole will arise and corrosion resistance and strength will fall.

On the other hand, the relationship between the attritor uptime and the average particle diameter of the coal tar pitch residue to be pulverized was observed, and the result was obtained as shown in FIG.

When the grinding is completed as above, remove the tungsten carbide bowl, separate the fine powder (tungsten carbide-containing coal tar pitch residue) aqueous solution using a fine sieve or spray driver, etc. Evaporate and remove.

The residue pulverized to the above average particle size is press-molded by a molding press made of a mold or rubber by a molding press or a cold isostatic press (CIP).

In the present invention, it is preferable to use a molding press to produce a relatively small molded article, and to use a CIP to produce a slightly larger molded article, and the molding pressure is preferably 1-2Ton / cm 2.

When the molding is completed as described above, the molded body is carbonized and graphitized according to the intended use. In order to manufacture a carbonaceous material (product), the molded body is fired for 1-2 hours at a temperature range of 1000-1200 ° C. In the case of preparing a graphite material (product), the carbonized fired body as described above is fired at 2000 ° C. or higher, preferably, 2000-3000 ° C. for 1-2 hours.

When firing in order to produce a carbonaceous material as described above, the preferred heating rate is up to 1000 ° C to 1200 ° C, the firing temperature is 2 ° C / min. It is preferable to raise the temperature at an arbitrary heating rate up to -1200 ° C, if possible at a high speed, and to raise the temperature at a temperature rising rate of 6-8 ° C / min from 1000-1200 ° C to 2000 ° C or more.

Of course, in the case of manufacturing the graphite material, the temperature of the graphite at a temperature of 6-8 ℃ / min directly at a temperature of 6-8 ℃ / min without the cooling to room temperature after the carbonization at 1000-1200 ℃, that is to raise the temperature above 2000 ℃ Of course it is possible.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

The coal tar pitch having the industrial analytical value as shown in Table 1 and the elemental analytical value as shown in Table 2 was put in a heat resistant reactor, and heated and dried under conditions of 480-530 ° C. and 1.0-2 hours. Coal tar pitch residue (self-sintering coke) having an elemental analysis value such as was prepared.

The coal tar pitch residue thus prepared was dry pulverized with a ceramic ball mill to an average particle diameter of 120 μm or less, and then the container, the rotating shaft and the grinding bowl were averaged with a wet art writer made of tungsten carbide. The fine powder was pulverized to a particle size of 2-5 占 퐉, and the elemental analysis value and average particle size of the fine pulverized product were investigated.

As shown in Table 5, it can be seen that tungsten carbide is added 0.2-0.5% in the coal tar pitch residue.

The finely ground coal tar pitch residue as described above was sufficiently dried and molded into various forms at a molding pressure of 1.0-1.5 Ton / cm 2 in a hydraulic molding machine or CIP.

The molded articles molded as described above were charged with electricity and carbonized. At this time, the carbonization was controlled by raising the temperature to around 1200 ° C. while controlling the temperature increase rate according to the shape or size of the molded article.

As described above, real photographs of circumference, footnote, cylinder, disc, and sheet shape of the carbonized molded body were observed, and the photograph is shown in FIG.

Next, the carbonized molded body was raised to 2300 degreeC as mentioned above, and the graphitization process was performed.

The bulk density of the sample molded as described above, the sample carbonized after molding and the sample carbonized after carbonization were measured, and the measurement results are shown in Table 7 below.

As shown in Table 7, the carbonization density of the invention sample (1-2) is in the range of 1.64-1.75g / cm 2, and the graphitization density shows high carbonization density and graphitization density in the range of 1.84-2.16g / cm 2. It can be seen that.

Example 2

Mechanical properties, that is, compressive strength, bending strength, tensile strength, and Shore hardness of the inventive sample (1-2) shown in Table 7 of Example 1 were measured, and the results are shown in Table 8 below.

In addition, Table 8 also shows the mechanical properties of the conventional carbon material in order to compare with the high-density carbon material of the present invention.

As shown in Table 8, it can be seen that the inventive material (1-2), which is a carbon material manufactured according to the present invention, has very excellent mechanical properties compared to the conventional materials (A-F).

As described above, the present invention can easily and economically produce high density and high strength carbon or graphite materials, and therefore, graphite metallurgical crucibles, molds, materials, such as brake discs, bearing mechanical seals, packings, dies, plates, etc. There is an effect that can be appropriately used in the field of heat-resistant materials such as graphite rolls, heat exchanger pipes.

Claims (2)

Carbonizing the coal tar to produce a coal tar pitch having a melting point of 62-72 ° C .; The coal tar pitch was heated to 480-520 ° C. in an inert atmosphere at a temperature increase rate of 5-10 ° C./min, and subjected to dry distillation heat treatment maintained at this temperature for 1-2 hours to test the tar pitch of JIS K 2425. Preparing an 2.4-5.3 wt% coal tar pitch residue from β-resin (Resin) defined as the insoluble Quinoline minus the insoluble content; Pulverizing the coal tar pitch residue and removing adhering water; Molding the coal tar pitch residue pulverized as described above in a conventional method; And carbonizing the molded body of the coal tar pitch residue molded as described above in a temperature range of 1000-1200 ° C. for 1-2 hours to produce a carbonaceous material. In the above, the pulverization step of the coal tar pitch residue is composed of a dry grinding process and a wet grinding process; In the dry grinding step, coarsely pulverizing so that the average particle diameter of the coal tar pitch residue becomes 120 µm or less; In the wet grinding process, the average particle diameter of the coal tar pitch transfer material is 2-5 μm in an attritor grinder including a grinding vessel having a tungsten carbide internal rotating shaft, a tungsten carbide rotating shaft, and a tungsten carbide bowl. A method for producing a high-density carbonaceous material having excellent mechanical properties, characterized by pulverizing tungsten carbide having an average particle diameter of 2-5 탆 to 0.2-0.5wt% by abrasion of constituent members by tungsten carbide bowl of an attritor mill. Carbonizing the coal tar to produce a coal tar pitch having a melting point of 62-72 ° C .; The coal tar pitch was heated to 480-520 ° C. in an inert atmosphere at a temperature increase rate of 5-10 ° C./min, and subjected to dry distillation heat treatment maintained at this temperature for 1-2 hours to test the tar pitch of JIS K 2425. Preparing a coal tar pitch residue containing β-resin (β-Resin), which is defined as minus insoluble Quinoline insoluble content; Pulverizing the coal tar pitch residue and removing adhering water; Molding the coal tar pitch residue pulverized as described above in a conventional method; Carbonizing the molded article of coal tar pitch residue formed as described above in a temperature range of 1000-1200 ° C. for 1-2 hours; And producing a graphite material by performing a graphitization treatment of firing the carbonized fired body at a temperature of 2000 ° C. or higher for 1-2 hours as described above, wherein the coal tar is produced. The pulverization step of the pitch residue is composed of a dry grinding process and a wet grinding process; In the dry grinding step, coarsely pulverizing so that the average particle diameter of the coal tar pitch residue becomes 120 µm or less; In the wet grinding process, the average particle diameter of the coal tar pitch transfer material is 2-5 μm in the attritor pulverizer including a grinding vessel having a tungsten carbide inside, a tungsten carbide rotating shaft, and a tungsten carbide bowl. A method for producing a high-density carbon material having excellent mechanical properties, characterized by grinding so that tungsten carbide having an average particle diameter of 2-5 탆 is added by abrasion of constituent members by tungsten carbide bowl.