JPH01103910A - Method for granulating carbonaceous powder - Google Patents

Abstract

PURPOSE:To produce granulated carbonaceous powder capable of providing a compact having a specific resistance value comparable to graphite and excellent flexual strength by spray-drying a slurry wherein carbonaceous powder contg. self-sintering carbonaceous powder and a specified binder and a specified wetting agent are dispersed into water. CONSTITUTION:A slurry is obtained by dispersing 100pts.wt. carbonaceous powder contg. self-sintering carbonaceous powder (e.g., coal tar pitch) and at least one kind of powder (e.g., SiC) selected from graphitic carbon, carbonaceous carbon, metals, and inorg. compds., 0.01-5pts.wt. binder (e.g., methylcellulose whose 2% aq. soln. has 25-2,000cps at 25 deg.C) consisting of an org. compd. not forming a foamed body when carbonized at 1,000 deg.C and having >=10pts.wt. residual carbon yield, and 0.01-3pts.wt. nonionic surfactant (e.g., alkylphenol- ethylene oxide adduct) having >=25 deg.C clouding point as a wetting agent into water. The slurry is spray-dried while controlling the inlet temp. to about 180 deg.C and the outlet temp. to about 100 deg.C, and carbonaceous powder having 50-500mum mean particle diameter is obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for granulating carbon-based powder.

Specifically, a carbon-based powder containing a self-sintering carbon-based powder and optionally at least one type of powder selected from the group consisting of graphitic carbon, carbonaceous carbon, metals, and inorganic compounds is mixed with a binder and moistened with a binder. The present invention relates to a method of granulating a slurry dispersed in water in the presence of an agent by spray drying it in heated air that may contain superheated steam.

More specifically, the present invention provides at least one pitch powder selected from the group consisting of coal tar pitch, petroleum pitch, naphtha cracked tar pitch, mesophase-containing pitch, and various modified pitches and/or the pitch group. Defined as a composite powder of at least one type selected from the group consisting of graphitic carbon, carbonaceous carbon, metal, and inorganic compound whose surface is substantially coated with at least one type of pitch selected from A carbon-based powder consisting of a self-sintering carbon-based powder and at least one type of powder selected from the group consisting of graphitic carbon, carbonaceous carbon, metals, and inorganic compounds added as desired is combined with a binder and a carbon-based powder. The present invention relates to a method of forming a water-dispersed slurry in the presence of a wetting agent, followed by spray drying and granulation in heated air that may contain superheated steam. According to the present invention, when a granulated powder is poured into a mold and press-molded to obtain a product having a complicated shape, and then carbonized and/or graphitized to obtain a carbon precision molded product, the cast It is possible to automatically fill various molds with narrow gaps and complicated pouring paths with good reproducibility without excess or deficiency, and it collapses uniformly against oppression, resulting in uneven filling density. A granulated powder with excellent properties can be obtained.

The granulated powder of the present invention not only brings about a manufacturing method change in that it enables large-leaf continuous molding in the field of small precision molded products using a mold using a press machine, but also enables hydrostatic press (CIP).
In the production of various block-shaped compacts made using high-temperature isostatic pressing (HIP), etc., good powder flowability not only increases the density of the compact, but also granulation aids (binder and wetting agent). Due to the feature of the present invention, which will be described later, that carbonaceous materials do not cause deterioration in the strength of the fired body, it is possible to provide a high-quality carbon-based block.

The granulated powder of the present invention can be produced by cold processing using a mold, instead of the conventional cutting process from a carbonaceous and/or graphite block molded body, which is compact and has precise dimensional accuracy. This material is suitable for production by molding, molding, and subsequent carbonization and/or graphitization.

[Conventional technology]

This article describes the production of molded bodies using conventional cutting processes and its problems.

Among carbon precision molded products, large products such as graphite heaters and graphite crucibles have the advantage that by cutting out large blocks, the unused parts can be used as small blocks and used as material for smaller molded products. Furthermore, since the product itself occupies the heart of a semiconductor crystal growth device, functionality is given priority over product price, and therefore it is positioned as a material that cannot be replaced by other materials. On the other hand, in fields such as sliding parts of industrial rotating equipment (for example, parts of oil-free compressor cylinders) and nuclear reactor materials, where damage can directly lead to serious safety and economic losses, we have established a system based on many years of experience. For reliability, high-density graphite block is used as the main material.

It is well known that carbonaceous and graphitic carbon materials are materials with well-balanced properties such as heat resistance, thermal conductivity, electrical conductivity, chemical resistance, sliding properties, and strength. Despite this, one of the reasons why carbon products, such as plastic products, are not used in large quantities in various forms in various industrial fields is that the price of molded products is inherently high. There are circumstances.

For example, if we consider a graphitic carbon block, it is created through a long process that begins with pulverization of raw material coke, pitch kneading, pulverization, isostatic pressing, carbonization (re-impregnation, carbonization) and graphitization (demetallization). Even in a mass production process, the material must be expensive at 2,000 to 5,000 yen/9. () is a process for luxury goods.

Furthermore, from the carbon block, the bottom and length as illustrated in Figure 1,
If you try to cut out a hollow box-shaped thin inner box with horizontal cross-shaped partitions, half of the expensive materials will be cut out and lose value, and you will not be able to use high-class processing techniques such as corrugation. Since various special tools are required, there are processing constraints such as mass unmanned production using an automatic lathe being impossible, so the price per piece has to be at the level of several hundred yen. Therefore, there are radio wave shielding boxes for computer parts that operate under high heat and harsh environments, disposable jigs for producing large numbers of small hot-pressed products in one press, and small rutz for sputtering. Although these products are mass-consumed products, they were not evaluated in fields where not only functionality but also product price is strictly required.

In addition, carbon rods are used as the positive electrode of manganese dry batteries, but usually earthy graphite, scaly graphite, coke, etc. are uniformly mixed with tar and pitch, then heated and extruded for 90 minutes.
It is carbonized at 0 to 1000°C, and the pores created during firing are impregnated with paraffin or the like to make it waterproof before use. Although this method is excellent in terms of mass productivity, problems such as complicated process management and the necessity of a waterproofing process have been pointed out. Furthermore, in order to withstand the high load output required of dry batteries in recent years, improvements have been made not only to improve the mixture, but also to expand the contact area of the carbon electrode with the mixture and reduce the electrical resistance value. Ta. In JP-A No. 52-24210, flaky graphite is mixed with phenol or epoxy resin as a binder, then preformed so that the basal plane of graphite is oriented in the longitudinal direction, and then compressed under pressure in the longitudinal direction. We have proposed a method for forming carbon rods for dry batteries, which is characterized by solidifying and welding a binder by heating or other methods after re-molding. However, although this method makes it possible to close the pores, it does not seem to solve problems such as deterioration of the resin part due to contact with the mixture over many years and a decrease in production efficiency due to complicated molding techniques.

In reality, hundreds of millions of carbon rods are still being consumed using conventional methods.

That is, it can be seen that conventional block processing and carbonization omitting methods cannot produce products with complex shapes at low cost and in large quantities.

Attempts to solve these problems have been disclosed in recent years.

JP-A-60-112609 can be cited as an example of a technology for manufacturing molded objects such as springs, bolts, and nuts.

In this publication, a thermosetting resin monomer, bleed polymer, or low polymer is added as a binder to fine carbon powder containing carbonized or graphitized mesophase as an essential component, and the binder is applied after dispersion, mixing, and shaping. A method for producing a hard carbon molded article by polymerization hardening and firing in an inert atmosphere is disclosed. The molded product obtained by the method disclosed in the publication has a smooth surface and excellent strength and hardness, but the disclosed manufacturing process shows that the mesophase pitch is heat treated → separated from the matrix → heated at 1000 to 2700°C. It has been shown that it is necessary to go through two carbonization steps: firing → composite with resin (dispersion, mixing, thermal condensation with heated rolls) → pelletization → shaping → infusibility → carbonization.

Japanese Unexamined Patent Application Publication No. 1983 (1983) as a method for manufacturing carbon molded bodies using a press machine
There is a publication No.-113509. According to the publication, graphite,
A suitable amount of raw materials such as carpin black and coke are combined with pitch tar and then turned into ultra-fine powder (5 microns).
The assembled material is granulated with phenol or polyvinyl alcohol, etc., and cold continuous molding is performed using a punch press using a mechanical cam-driven compression movement. Conventionally, it was considered difficult to form car pins for machines, but by adjusting the volatile content (7-11%) during powder granulation and the eccentric mechanism of the cam movement, it has become possible to fill the powder with cold. Surface pressure between 1.5
t/cIn"-5t/c!IL", it was possible to mold to the product size with instantaneous cam compression for 2 to 3 seconds.

[Problem that the invention seeks to solve]

BACKGROUND ART Obtaining a powder compact using a cold press and sintering it to obtain a large amount of products with complex shapes is carried out on a large scale, for example, in ferrite-related industries. Integrally molded products such as transformer cores and parts of television tuners are manufactured using machines suitable for continuous molding, such as rotary presses. In order to produce compacts with high dimensional accuracy using this method, the ability to fill the mold cavity with powder is the governing factor, and granulation of the powder is essential to ensure the flowability of the powder. It is also known that there are

Therefore, those skilled in the art can easily infer that it is necessary to granulate carbon-based powder in order to subject it to powder compaction.

However, it has been found that the following problems occur when attempting to obtain granulated powder from a carbonaceous material, particularly the carbonaceous powder that the present inventors intend to subject to molding.

(1) When the phenol or polyvinyl alcohol disclosed in JP-A-62-113509 is used as a binder, it has been found that the strength of the molded product is significantly reduced and the molded product foams during firing. Served.

A water-soluble binder that gives a carbonized product with a carbonization yield of less than 100% by weight or a foamed carbonized product even if the carbonization yield is less than 100% by weight in an experiment in which a powder or molded product containing the binder alone was fired in 4 hours to 100OC. found that when used as the granulation binder of the present invention, all of them result in either or both of a decrease in strength and foaming of the molded product. That is, in selecting a water-soluble binder essential for producing granulated powder, the present inventors made sure that the residual carbon yield was 10% by weight or more and that the fired product itself did not foam. I have found that it is essential.

This is a departure from the conventional concept of a compound that scatters carbon at around 500°C, which was common knowledge for granulated binders for ferrite and ceramics, and was unexpected for those skilled in the art. Ta.

(2) On the other hand, in addition to the self-sintering carbon-based powder which is an essential component of the carbon-based powder used in the present invention, JP-A-62-11
Carbon-based materials containing pitch, such as the biticital binding material disclosed in Publication No. 3509, are lipophilic unless chemically treated such as surface oxidation. Therefore, for granulation, a method is generally used in which the powder is slurried together with a binder in an organic solvent, and the slurry is spray-dried and granulated in an inert gas stream.

However, this method complicates the granulation process due to the recovery of the organic solvent from the inert gas and the recycling of the organic solvent, and increases the granulation cost, which significantly impedes the production of inexpensive molded bodies, which is the objective of the present invention. It was found that this is a contributing factor.

The present inventors focused on the fact that the self-sintering carbon powder, which is the main component of the carbon-based powder used in the present invention, does not substantially become infusible in air below 200°C, and may contain superheated steam. We have conducted extensive studies to significantly reduce granulation costs by implementing spray drying granulation using heated air and water slurry. As a result, in order to stably disperse the lipophilic carbon-based powder in water, wetting agents such as alkylphenol ethylene oxide adducts, ethylene oxide propylene oxide adducts, oxyethylene oxypropylene block polymers (average molecular weight 2000-5000
), alcohol ethoxylates, polyhydric alcohol esters, polyethylene glycol esters, and other nonionic surfactants were found to be effective, leading to the completion of the present invention.

[Means for solving problems]

(Structure of the Invention) That is, the present invention comprises: 1. A self-sintering carbon-based powder and, if desired, at least one type of powder selected from the group consisting of graphitic carbon, carbonaceous carbon, metals, and inorganic compounds. In a method of granulating a slurry in which a carbon-based powder containing carbonaceous powder is dispersed in water in the presence of a binder and a wetting agent, the slurry is spray-dried in heated air that may contain superheated steam, (1) the binder is It is an organic compound that forms a foam when carbonized at 1000°C and has a residual carbon yield of 100% by weight or more, and the amount used is 0.01 to 5 parts by weight per 100 parts by weight of carbon-based powder; (2) The wetting agent is a nonionic surfactant having a line point range of 25°C or higher and 11M, and the amount used is 0 per 100 parts by weight of carbon-based powder. .01 to 3 parts by weight, 2. The self-sintering carbon-based powder is coal tar pitch, petroleum pitch, naphtha cracked tar pitch, mesophase-containing pitch, and At least 1m selected from the group consisting of various modified pitches! at least one selected from the group consisting of graphitic carbon, carbonaceous carbon, metals and inorganic compounds whose surfaces are substantially coated with pitch powder of the class Is or/and pitch of the class Is selected from the pitch group. The carbon-based powder according to claim 1, which is a machine powder of Class IA, and is obtained by carbonizing a room-temperature press molded product in an inert gas atmosphere at a temperature of at least 500°C to obtain a sintered body. This is a method of granulating the body.

(Detailed Description of the Invention) Self-sintering carbon-based powder The self-sintering carbon-based powder used in the present invention is characterized by the fact that it can be formed into a compact by pressing at room temperature, and can be carbonized up to 500-600°C. It can be defined as ``carbon-based powder that can give a sintered body by reaction.''

Examples of such carbon-based powders include pitch, and pitches that can be used in the present invention include coal tar pitch, petroleum residue tar pitch, ethylene heavy end tar pitch, etc. Pitch powder obtained by pulverizing a solid can be mentioned. Furthermore, modified pitch powder obtained by treating the above-mentioned pitches with hydrogen or a hydrogen-donating organic compound (eg, tetrahydroquinoline or decalin) can also be used.

Optional Addition Powders Also, among the powders that may be added as desired, examples of graphitic carbon include raw graphite, flaky graphite, artificial graphite powder, and graphite fibers. Carbonaceous carbon includes petroleum coke, coal coke, carbon black, carbon fiber,
Examples include powders such as mesophase pitch micropeas. Silica-alumina, r- as an inorganic compound
Alumina silicon carbide, silicon nitride, titanium carbide, silicon carbide,
Titanium oxide is used as a metal, - iron, copper, aluminum, zinc, tin, nickel, cobalt, gold, silver, platinum, titanium, lead, and as a metal oxide, oxidized steel, lead oxide, iron oxide,
For example,

Examples of mesophase-containing pitch raw materials include coal tar, naphtha cracked tar, vacuum distillation residue oil, coal pitch, naphtha cracked tar distilled pitch, and hydrogen-treated pitch or solvent-precipitated pitch.

The mesophase-containing pitch powder can be produced by, for example, heat-treating naphtha cracked tar under reduced pressure or in an inert gas atmosphere to remove the light-boiling fraction, promote meso-ization, and then crush and granulate it by the method of the present invention. can.

A composite powder method in which the surface is coated with mesophase-containing pitch can be used. Further, the slurry is poured into a solvent such as acetone or hexane to precipitate a polycyclic aromatic polymer containing a mesophase-containing pitch precursor on the surface of the material, and the powder is separated from the slurry, and then subjected to heat treatment and further pulverized. You can also get it by doing this.

It can be produced using the mesophase-containing pitch powder used in the present invention and the patent application specification entitled "Method for producing raw material for carbon-based composite molded body" filed on September 18, 2013.

Mesophase-containing pitches that have completely lost their cohesive components due to long-term high-temperature heat treatment are not included in the materials that can be used in the present invention.

In the method of the present invention, Menkagen microbeads and Menphase pitch powder are used as self-sintering carbon powder,
By forming a water slurry with powder such as flaky graphite or artificial graphite, and granulating this, it simultaneously ensures slipperiness during molding and high thermal conductivity and electrical conductivity of the fired compact at around 1000℃ firing. be able to. If necessary, metal powders such as copper, silver, and iron can coexist. In addition, by slurrying and granulating self-sintering carbon powder, in which the surface of graphitic carbon, metal, or inorganic compound is coated with pitch or menphase-containing pitch, and menphase-containing pitch powder, it has both high hardness and strength. Moreover, it is possible to provide an excellent carbon-based molded body having excellent releasability from a mold and high electrical conductivity and thermal conductivity.

In the method of the present invention, fine powder compounds such as SIC, TIC, and BN and their precursors can be selected as constituent components in the granulated powder, and the oxidation resistance can also be improved.

The water slurry used in the present invention can be produced by stably dispersing carbon λ-based powder in water using a wetting agent, and adding a binder to maintain the particle shape of the granulated powder.

The higher the concentration of carbon-based powder in the slurry, the more cost reduction can be achieved. Arbitrary excursions can be achieved by designing the particle size and particle size distribution. 5 to 3 parts of 100 TL of water
00 parts by weight, preferably in the range of 10 to 200 parts.

Binder The following water-soluble i-like compounds can be mentioned as the binder used in the present invention. String polymerized products of methylcellulose and hydroxycellulose are preferred. On fire, the viscosity of a 2% aqueous solution of the above compound at 20°C is 25 to 2000.
Centipoise polymer products are more preferred.

The binder should be selected so that the residual carbon yield when carbonized at 1000°C in an inert gas atmosphere is 10 or more, preferably 15 or more. It is more preferable to use a material that does not form a body and preferably has the property of being baked and hardened. Compounds other than those mentioned above can also be used as the binder of the present invention, as long as they have such properties and are water-soluble.

Such a binder can be used in an amount of 0.01 to 5 parts by weight, preferably 0.02 to 4 parts by weight, and more preferably 0.05 to 3 parts by weight, based on xooBz parts of the carbon-based powder.

If the amount of binder used is more than 5 parts, the strength of the carbonized product may decrease or the molded product may foam. on the other hand,
If the amount used is less than 0.01 part, it will be difficult to granulate the carbonized powder.

Wetting agent As the wetting agent used in the present invention, a nonionic activator having a cloud point range of 4 points above 25°C, preferably 30-90°C can be selected.

Examples of wetting agents include alkylphenol ethylene oxide adducts or ethylene oxide propylene oxide adducts, oxyethylenepropylene/block-limer (average molecular weight 2000-sooo), alcohol ethoxylate), poly(i[[i alcohol ester, 4
') Ethylene glycol ester etc. can be selected. Such wetting agents.

0.01 to 3 parts by weight, preferably 0.05 to 2 parts by weight, more preferably 0.05 to 2 parts by weight, per 100 parts by weight of carbon-based powder.
1 to liter can be used.

Note that if more than 3 parts by weight of the wetting agent is used, the strength of the molded article will be significantly reduced. On the other hand, if the amount of the wetting agent is less than 0.011 parts by weight, the dispersibility of the carbon-based powder becomes significantly poor.

When the wetting agent of the present invention is used, the carbon-based powder of the present invention can be dispersed without bubbles even at a high concentration of 300 parts by weight per 100 parts by weight of water. In addition, bubbles are not generated even in the presence of the above-mentioned binder.

In addition, if air bubbles are included in the slurry, the dimensional stability and strength of the molded product may be adversely affected, such as the generation of voids during compression molding due to uneven particle size distribution of the granulated particles and hollowing of the granulated particles. Become.

Appropriate amounts of the binder and wetting agent can be set within the above range depending on the surface area of the carbon-based powder.

The slurry of spray-dried carbon-based powder can be flash-dried using a conventional spray-drying granulator, and the carbon-based granulated powder can be recovered. Heated air can be used as the granulation heating medium in the present invention. In addition, superheated steam vapor can also be used. It is essential that the upper limit of the hot air temperature does not exceed 200°C. When the hot air comes into contact with the slurry droplets, the temperature drops rapidly, for example, the temperature at which it enters the chamber is 80°C.
The exit temperature will be 100°C. When dry carbon powder comes into contact with air at a temperature of 200° C. or higher, the infusibility reaction progresses, making it impossible to achieve the original purpose of imparting caking properties to a molded article using the pitch of the present invention. The granulation particle size is determined by slurry concentration and supply amount, hot air temperature and amount, water vapor coexistence amount, droplet particle size,
It is determined by various chemical engineering factors such as the dryer body diameter. The average value of the granule diameter can be selected from 50 to 500 μm, preferably from 75 to 400 μm. If the particles are too fine, flowability will be inhibited; if the particles are too large, uniformity in filling a narrow mold cavity will be inhibited. The average particle size and deviation from it (particle size distribution) can be set depending on the wall thickness and shape of the molded product.

The present invention will be explained in more detail with reference to the following examples.

〔Example〕

Example 1 Ethylene heavy end tar (EHE tar) 2640
, P is scaly graphite (CPB) 400 manufactured by Nippon Graphite Industries.
．． 9 was added and stirred to prepare a slurry liquid. The slurry liquid was poured into the acetone solution of 7910.91 (101) which was being stirred, and stirring was continued for 5 minutes after the addition was completed.
After allowing the mixture to stand still for a minute, the supernatant liquid was removed using a decantation cylinder, and then acetone 51 was added and stirred for 5 minutes.

Let it cool for at least 15 minutes, then remove the supernatant liquid by decantation, then use a Nutsche with 4A PM attached.

Filtered under reduced pressure with an aspirator, resulting in brown powder 16
00g was dried on a stainless steel pad for 5 hours on a hot plate maintained at 60°C.
I got it.

Pour dry powder 190.9 mm into a wide-mouthed glass cylinder (inner diameter 80 mm
, height 230 tm), and this was placed in a SUS reactor equipped with a gas blowing pipe. Preheating N2 (flow'J
The reactor was immersed in a night bath maintained at 479°C under flow (k7 l -STP/min), heat treated at 465°C for 15 minutes, and cooled to room temperature to obtain 1261 carbon-based composite molded material. . The amount of quinolinine dissolved in pitch pace determined by JIS-2425 centrifugation was 97 wt.

The raw material for the carbon-based composite molded body was milled in an alumina ball mill for 5 minutes.
A carbon-based powder was obtained by fractional pulverization.

Carbon-based powder 120Ii was mixed with methyl cellulose 80-120
Centipoise (manufactured by Gyudon Chemicals) 1.22#, chain point 44
°C SN Wet 366 (manufactured by Sannopco, solid content 70
h) A slurry liquid was obtained by adding 0.85N to a solution of 244I of water and stirring. The slurry liquid was atomized using Okawara Kakoki's spray dryer FOC-16 with a diameter of 651 m.
φ, rotation speed 11000 Orp, hot air temperature 180°C, supply amount 5 m/rtin, slurry spray-jio, 13
kl? / value to obtain granulated powder with an average particle size of 114 μm.

The granulated powder was processed using a rotary press machine (Kanatsu Seiki ■) 400-
A wall thickness of 1.2 mm with a shape as shown in Figure 1 set as an IP type.
A mold cavity capable of producing a hollow box-shaped thin-walled product with a bottom of m and vertical and horizontal cross-shaped partitions was filled, and the density of the formed body was set to 1.6217 CC at a speed of 6 revolutions per minute. Continuous production was carried out.

The obtained green body was fired by setting the heating time to 1000° C. for 9 hours, and a fired body with a fired body density of 1.611/F3 was able to be obtained with the same dimensional accuracy as the mold.

Example 2 In the same manner as in Example 1, nonylphenol 10KO (chain point 61°C, Emulgun 910 manufactured by Kako ■) was used as a wetting agent.
) was used, but the slurry could be prepared in the same manner as in Example 1. There was also no difference in the properties of the molded products.

Example 3 Guluronics activator (chain point 40°C, Daiichi Kogyo 2) 47420) was used as a wetting agent in the same method as in Example 1.
A slurry was prepared in the same manner as in Example 1, except that I11 was used, and a granulated powder could be obtained. There was also no difference in the properties of the molded products.

Comparative Example 1 Nonylphenol 6,0 K O adduct (
An attempt was made to prepare a slurry in the same manner as in Example 1 using 1 g of carbonaceous powder (with a clouding point of less than 20°C), but the slurry was completely dispersed. By using this, it is possible to measure various developments of carbon molded bodies. For example, a composite powder in which scaly graphite is coated with mesophase-containing pitch is disclosed in the prior art of the present inventors (Japanese Unexamined Patent Publication No. 61-13690).
Publication No. 6, Publication No. 61-251504, Publication No. 61-25
No. 1505, No. 62-123007), and can be granulated by the method of the present invention.

Even when an attempt was made to fill the ungranulated product into the cavity of the box mold shown in FIG. 1, it did not flow at all. However, the granulated product flows easily, and a thin-walled product with a complicated shape having an inner thickness of 1.2 mm as shown in FIG. 1 can be produced in continuous unmanned operation. Regarding productivity, for example, if a rotary Gress 400-IP type machine manufactured by Kanatsu Seiki ■ is used, at least 80 pieces can be molded per minute. In other words, after 8 hours of operation, 38
It is possible to make a huge quantity of 400 pieces, and unmanned operation at night is also possible (#) The large production capacity of one press machine is clear. Furthermore, it is possible to simultaneously produce not only molded products of the same type but also up to eight different shapes.

In this case, the production amount of each molded body is 178, but it is possible to produce 4800 molded bodies in 8 hours.

The advantages of producing a molded body using the granulated powder of the present invention are also exhibited in the firing process. That is, in the case of a thin C-shaped compact as shown in FIG. 1, the firing time can be significantly shortened. This is because pitch containing menphase has a residual carbon yield exceeding 80% by weight, so the amount of gas released during firing is significantly smaller than that of other tars and pitches, and the gas diffusion distance is significantly shorter than that of large blocks. It is assumed that it originates from etc. 10
Even if the heating time to 00° C. was set within an arbitrary range of 1 hour to 10 minutes, problems such as blistering and cracking of the fired product did not occur.

Therefore, continuous firing in a tunnel type kiln or the like for mass-produced products can be easily designed.

Utilizing the above characteristics, carbon rods for dry batteries can also be mass-produced after being given various shapes. That is, conventionally only round bars have been put to practical use. On the other hand, as the uses of batteries expand, batteries that can handle large capacity loads are required, and improvements in the performance of mixture components are being made. If it becomes possible to mass-produce carbon rods that have a larger contact area with the mixture than conventional products, a lower mixture contact resistance value, and a lower seed rod internal resistance, it will be possible to improve the added value of manganese dry batteries. can. From this point of view, the present inventors' granulated powder has characteristics that can achieve the purpose.

The purpose can be achieved by forming a composite powder of flaky graphite and menphase-containing pitch into a cylinder with a semicircular notch in the length direction, as shown in Figure 2. can. The object can also be achieved by applying a composite powder with a high t'FL carbon black (for example, Ketchien EC) to a molded body as shown in FIG. The former can exhibit a specific resistance value (1mΩ・CI!L) comparable to that of graphite when fired at 1000℃, while the latter has a specific resistance value comparable to that of graphite and a bending strength exceeding 500 kg/cm" when fired at 1700-2000℃. It is possible to give a molded body with

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a thin box-shaped inner product manufactured using the granulated powder obtained by the method of the present invention, and FIG. FIG. Patent Applicant: Mitsubishi Yuka Co., Ltd. Representative Patent Attorney Masahisa Hasetani Representative Patent Attorney Takaya Yamamoto Figure 1 Figure 2 Procedural Principal's official seal) December 1'f, 1986

Claims (1)

[Claims] 1. Self-sintering carbon-based powder and optionally graphitic carbon,
A slurry prepared by dispersing carbon-based powder containing at least one kind of powder selected from the group consisting of carbonaceous carbon, metals, and inorganic compounds in water in the presence of a binder and a wetting agent may also contain superheated steam. In a certain method of granulation by spray drying in heated air, (1) the binder is an organic compound that does not form a foam upon carbonization at 1000°C and has a residual carbon yield of 10% by weight or more, and the amount used is 0.01 to 5 parts by weight per 100 parts by weight of carbon-based powder; (2) the wetting agent is a nonionic surfactant having a cloud point of 25° C. or higher; A method for granulating carbon-based powder, characterized in that the amount used is 0.01 to 3 parts by weight per 100 parts by weight of carbon-based powder. 2. The self-sintering carbon-based powder is at least one type of pitch powder selected from the group consisting of coal tar pitch, petroleum pitch, naphtha decomposition tar pitch, mesophase-containing pitch, and various modified pitches, and/or said pitch. at least one type of composite powder selected from the group consisting of graphitic carbon, carbonaceous carbon, metal, and inorganic compound whose surface is substantially coated with at least one type of pitch selected from the group, and at room temperature. The method for granulating carbon-based powder according to claim 1, wherein a sintered body is obtained by carbonizing a press-formed product in an inert gas atmosphere at a temperature of at least 500°C.