JPH05330813A - Production of raw material for high purity special carbonaceous material - Google Patents

Abstract

PURPOSE:To obtain a raw material for high purity special carbonaceous material having a prescribed coefficient of volumetric shrinkage, bending strength or the like by heat treating a carbonaceous raw material specified in volatile matter(VM), toluene soluble matter(TS), free swelling index, and Roga index or the like. CONSTITUTION:The carbonaceous raw material having <=40% VM, <=40% TS measured at the time of adjusting average particle diameter to 15-20mum, having a specific property and free from ash matter is heat-treated. As the specific property, one or more is selected from >=200 deg.C incipient fluidization, 1-9 free swelling index, 30-90 Roga index and 30-90% optically anisotropic structure >=30mum in size, and the product obtained by heat-treating has the properties of 3-20% VM, 1-10%gamma resin content measured at the time of adjusting average particle diameter to 15-20mum, >=10% coefficient of volumetric shrinkage in a bar-shaped molded body molded at 1t/cm<2> molding pressure and fired at 1000 deg.C, >=200kg/cm<2> bending strength in the fired body or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a highly pure and highly dense special carbon material. More specifically, it relates to a method for producing a raw material for a high-purity special carbon material having high bulk density and high mechanical strength.

[0002]

2. Description of the Related Art Conventionally, a high-purity special carbon material is manufactured by mixing coke such as pitch coke and petroleum coke with a binder pitch at a predetermined ratio, and then crushing and molding the mixture. Furthermore, after firing and graphitizing this molded body, it is processed to produce a special carbon material, and then a high-purity special carbon material is produced by performing a high-purification treatment in a fluorine or chlorine gas stream at high temperature. ..

[0003] Recently, a method for producing a carbon material by molding mesocarbon microbeads obtained by treating a pitch with a solvent after heat treatment and firing it has also been reported. The high-purity special carbon material is manufactured by performing high-purification treatment at.

[0004]

However, these methods have insufficient product characteristics such as low bulk density and low strength, and require high purification treatment because they contain a large amount of ash. Therefore, there is a problem that the process must be performed many times, the process is complicated, the manufacturing cost is high, and the like, and the advent of a method for manufacturing a high-purity special carbon material that has better characteristics at lower cost is desired.

Further, in recent years, high-purity special carbon materials have been reviewed with the development of the semiconductor industry and the development of energy utilization technologies such as nuclear power and nuclear fusion, and are particularly large in size, high in strength, and low in impurities. A high-purity special carbon material with strong corrosion resistance is required.

[0006]

The inventors of the present invention have made extensive studies in view of the above situation, and as a result, heat treatment of a carbonaceous raw material having a certain property to form a carbonaceous powder and production of a carbonaceous material are highly effective. It was found that a high purity special carbon material can be obtained, and the present invention has been completed. That is, the gist of the present invention is that the volatile matter (VM) is 40% or less, and the toluene soluble matter (TS) is 40% when measured by adjusting the average particle size to 15 to 20 μm.
A raw material for a high-purity carbon material, which is characterized in that the carbonaceous raw material having one or more of the following (1) to (4) and having substantially no ash content is heat-treated. Manufacturing method.

(1) The flow starting temperature of the carbonaceous raw material is 20
0 ° C. or higher (2) Button index is 1 or higher (3) Logger index is 30 or higher (4) Optically anisotropic structure having a size of 30 μm or more is 30
The present invention will be described in detail below.

First, the carbonaceous raw material according to the present invention has a volatile content (VM) of 40% by weight or less and an average particle size of 15 to 2
Toluene soluble matter (TS) when measured by adjusting to 0 μm
(Γ resin) is 40% by weight or less. When the VM of the carbonaceous raw material exceeds 40%, it takes time to adjust the properties of the heat-treated product to a target value, and there is a problem that the treatment capacity is lowered and the cost is increased. V
M is 40% or less, preferably 10 to 35%, and most preferably 15 to 30%. Further, if TS is too high, the light boiling fraction is large, the dispersion of the raw material is deteriorated, and the characteristics are deteriorated. Therefore, the TS of the carbonaceous raw material is 40% or less,
Furthermore, 10 to 35% is preferable, and most preferably 15
~ 30%.

Further, the carbonaceous raw material in the present invention is
It satisfies one or more of the following characteristics (1) to (4). (1) Since the heat treatment of the carbonaceous raw material is usually performed at a temperature of 200 ° C. or higher, the flow starting temperature of the carbonaceous raw material is 20
When the temperature is 0 ° C. or lower, the carbonaceous raw material is melted at the time of heat treatment and becomes a lump, which cannot be uniformly processed. It is more preferably 220 to 500 ° C, and most preferably 250 to 450 ° C.

(2) The button index of the carbonaceous raw material is preferably 1-9, more preferably 1.
5 to 7, most preferably 2 to 7. Here, the button index is measured according to JIS M 8801, and the measured particle size is the particle size when mixed with coke or the like. (3) The carbonaceous raw material preferably has a Roga index of 30 to 90, more preferably 35 to 90, and most preferably 40 to 90.

(4) Further, the size of the optically anisotropic structure observed by a polarization microscope is 30 μm or more.
~ 90% present carbonaceous raw materials are preferred, and further 50
It is preferably 30 to 90% of those having a thickness of at least μm, and most preferably 50 to 90% of having a thickness of at least 50 μm. The ratio of the optically anisotropic structure was represented by an average value of a sample prepared by a conventional method, which was observed by a dry method in a visual field of 10 points at a measurement magnification of 200 times.

Various pitches can be used as these carbonaceous raw materials. For example, coal tar by-produced during coal carbonization, coal tar pitch obtained from this is added statically by adding a solvent such as an aromatic solvent such as toluene, an aliphatic solvent such as kerosene, or a cycloaliphatic solvent such as cyclohexane. Those obtained by removing ash by means of standing separation, centrifugation, filtration or the like, those obtained by mixing calcined coke substantially containing no ash, raw coke, etc., and those obtained by heat-treating the mixture can be used. Further, petroleum heavy oil substantially free of ash and petroleum heavy oil from which ash has been removed or heat-treated products thereof, hydrogenated products thereof, and ash removed from those heat-treated products In addition, those obtained by polycondensing low molecular weight compounds such as naphthalene to remove ash such as catalyst in pitch, heat-treated products thereof, in coal liquefaction obtained by hydrogenating bituminous substances such as coal Ash-removed catalysts, heat-treated products thereof, and heavy components obtained by treating them with a solvent, and those heat-treated products that do not substantially contain ash can be used. .. Furthermore, a mixture of the heat-treated product and the like,
Further, carbon black which does not substantially contain ash, fine powder such as calcined coke, activated carbon and the like mixed with the heat-treated product and the like, and further heat-treated one thereof may be used.

In the carbonaceous raw material of the present invention, the above pitches are used in a delayed coker, autoclave, etc.
It can also be obtained by appropriately combining heat treatment at 0 to 500 ° C. for about 1 to 72 hours, and further solvent treatment. At that time, the heat treatment may be performed in an inert atmosphere, an autogenous atmosphere, or further in the presence of oxygen. The heat treatment may be performed in a stationary state, but may be performed in a fluid state and a stirring state.

In the present invention, "substantially free of ash" means that the ash content is 0.2% or less, more preferably 0.1% or less, most preferably 0.05% or less. is there. The raw material for high-purity special carbon material of the present invention is obtained by heating the carbonaceous raw material. The heat treatment of the carbonaceous raw material is usually 150 to 450 ° C., preferably 2
00-350 ° C., 0.1-48 hours, preferably 0.5
The treatment is performed for about 10 hours, but mechanical energy should be applied in order to perform the treatment uniformly and efficiently.

Examples of mechanical energy include stirring and ultrasonic waves. The heat treatment may be carried out in an inert gas (argon, nitrogen, etc.) under autogenous pressure or in the presence of air. The resulting heat treated product is shown below
It has one or more characteristics. VM is 20% or less and 3% or more, and the γ-resin amount is 10% or less and 1% or more when measured by adjusting the average particle size to 15 to 20 μm. Rod-like at a molding pressure of 1 ton / cm ^2. The volumetric shrinkage is 10% or more when fired to 1000 ° C. The bending strength when firing a rod-shaped molded body to 1000 ° C at a molding pressure of 1 ton / cm ² is 200 kg / cm
² or more If the VM exceeds 20%, the weight loss during firing is too large,
There are problems such as deterioration of properties and cracking during firing.
If it is less than 3%, the sinterability is deteriorated and the characteristics are hard to come out. Therefore, the VM is preferably 3 to 20%.

Further, it is preferable that the TS amount is 1 to 10%, particularly 3 to 8% when measured by adjusting the average particle size to 15 to 20 μm. Furthermore, if the molded product shrinks, the volume decreases and the bulk density increases, so it is preferable that the molded product has a large shrinkage factor during firing, and the crushed product of the heat-treated product should be molded at a molding pressure of 1 ton / cm ^2. When the rod-shaped molded body is fired up to 1000 ° C., the volumetric shrinkage is preferably 10% or more, more preferably 15% or more,
Most preferably, it is 20% or more.

Further, it is preferable that the molded product does not lose its shape when it is molded and fired, preferably 1 ton / g of the pulverized product.
It is preferable that the bending strength of a molded body formed into a rod shape at a molding pressure of cm ² when fired up to 1000 ° C. is 200 kg / cm ² or more, more preferably 300 kg / cm ² or more, and most preferably 400 kg. / Cm ² or more.

Pulverization of the heat-treated product is carried out in a conventional manner, but ash may be mixed in from the pulverizer depending on the pulverization system. Therefore, it is better to select a pulverization system that does not easily mix ash. That is, ash content easily mixes depending on the material of the equipment that utilizes compression force, shearing force, and impact force between equipments or equipment, so select a material that does not easily mix, crush by self-impact force between particles It is better to choose the one that does.

The average particle size of the pulverized product is preferably 100 μm or less in order to obtain a good molded product, and preferably 0.1 to 50 in order to further improve the uniformity of the product and improve the properties.
The particle size is preferably 0.1 μm, more preferably 0.1 to 30 μm, and most preferably 0.1 to 20 μm. The pulverized product thus obtained is molded by ordinary molding, cold isostatic pressing or the like, and fired to give a bulk density of 1.7 to 2.0 and a bending strength of 50.
A high-purity special carbon material of 0 to 1000 kg / cm ² can be manufactured.

The calcination can be carried out in an inert gas or in a coke breeze and is carried out at a temperature of 800 to 1000 ° C. However, since ash may be mixed depending on the burning method, the ash is not mixed. It is better to choose one. That is, in the method of firing in a coke breeze, it is better to use a breeze in which ash is substantially absent, and it is advantageous to fire in an inert gas such as argon or nitrogen because ash is not mixed. ..

Further, graphitization is performed by a Tammann furnace, an Acheson furnace,
A conventional method such as an induction heating furnace can be used, and usually 2000 to 30
Although it is performed at 00 ° C, the induction heating method and the Tammann furnace are advantageous because they do not contain ash. The carbon material produced in this manner has a low ash content without being subjected to a purification treatment with fluorine, chlorine or the like.

[0022]

【Example】

Example 1 A coal tar pitch having an ash content of 0.01% or less was heat-treated in a delayed coker to obtain a VM of 21.6%, a γ resin amount of 23.2% and an ash content of 0.02% or less. The carbonaceous raw material (flow starting temperature: 250 ° C.) was heat treated at 230 ° C. for 70 minutes in the presence of air.

The VM of the heat-treated product was 14.3% and the amount of γ resin was 5.3%. This product was finely pulverized to have an average particle size of 18 μm by molding to obtain a molded product, which was calcined to 1000 ° C. in a coke breeze, and the volumetric shrinkage was 31.1%. This molded body was graphitized to 2800 ° C. in a Tammann furnace to obtain a molded body. The graphite compact had a bulk density of 1.91 and a bending strength of 67.
The ash content was 0 kg / cm ² and the ash content was 10 PPM or less.

Example 2 A coal tar pitch having an ash content of 0.01% or less was heat-treated in a delayed coker to obtain a VM of 22.3%, a γ resin content of 22.1% and an ash content of 0. 02% or less of carbonaceous raw material (Button index: 3.0) was heat-treated at 240 ° C. for 60 minutes in the presence of air. The VM of the heat-treated product was 14.5% and the amount of γ-resin was 5.5%.

The product was pulverized to an average particle size of 18μ
When m was used to obtain a molded body, which was then calcined in a coke breeze to 1000 ° C., the volumetric shrinkage was 32.3%. This molded body was graphitized to 2800 ° C. in a Tammann furnace to obtain a molded body. The graphite compact had a bulk density of 1.92, a bending strength of 710 kg / cm ² , and an ash content of 10 PPM or less.

Example 3 A coal tar pitch having an ash content of 0.01% or less was heat-treated in a delayed coker to obtain a VM of 22.3%, a γ resin content of 22.1% and an ash content of 0. 230% or less of carbonaceous raw material (there was 50% or more of the optically anisotropic structure having a size of 30 μ or more) in the presence of air.
Heat treatment was performed at 75 ° C. for 75 minutes.

The VM of the heat-treated product was 13.8% and the amount of γ resin was 5.4%. This product was finely pulverized to have an average particle size of 18 μm to obtain a molded product by molding, and the molded product was calcined in coke breeze to 1000 ° C., and the bending strength was 800 kg / cm ² . This molded body was graphitized to 2800 ° C. in a Tammann furnace to obtain a molded body. The graphite compact has a bulk density of 1.89 and a bending strength of 6
90 kg / cm ² , and the ash content was 10 PPM or less.

Example 4 A coal tar pitch having an ash content of 0.01% or less was heat-treated in a delayed coker to obtain a VM of 22.3%, a γ resin content of 22.1% and an ash content of 0. 02% or less of carbonaceous raw material (Loga index: 50) in the presence of air 2
Heat treatment was performed at 40 ° C. for 62 minutes.

The VM of the heat-treated product was 13.6%, and the amount of γ resin was 5.2%. This product was finely pulverized to obtain an average particle size of 18 μm by molding, and a molded product was obtained. The molded product was baked in coke breeze to 1000 ° C., and the bending strength was 900 kg / cm ² . This molded body was graphitized to 2800 ° C. in a Tammann furnace to obtain a molded body. The graphite compact has a bulk density of 1.90 and a bending strength of 7
It was 20 kg / cm ² and the ash content was 10 PPM or less.

Comparative Example 1 A coal tar pitch having an ash content of 0.2% was heat-treated in a delayed coker to obtain a VM of 22.6%, and γ
A carbonaceous raw material (flow starting temperature: 260 ° C.) having a resin amount of 21.2% and an ash content of about 0.4% is heated in the presence of air to give 230
Heat treatment was performed at 70 ° C. for 70 minutes. VM of heat treatment product is 1
At 3.8%, the amount of γ-resin was 5.5%.

This product was finely ground to an average particle size of 18 μm.
When m was molded, a molded body was obtained and calcined in coke breeze to 1000 ° C., and the volumetric shrinkage was 30.5%. This molded body was graphitized to 2800 ° C. in a Tammann furnace to obtain a molded body. The graphite compact had a bulk density of 1.91, a bending strength of 740 kg / cm ² , and an ash content of 100 PPM.

[0032]

EFFECTS OF THE INVENTION According to the present invention, a carbon material having a low ash content can be manufactured without the conventional purification treatment with fluorine, chlorine, etc., and the labor can be simplified and the process can be shortened. ..

Claims (2)

[Claims] 1. The volatile matter (VM) is 40% or less, the toluene soluble matter (TS) is 40% or less when measured by adjusting the average particle size to 15 to 20 μm, and ) To (4), the method for producing a raw material for a high-purity special carbon material, which comprises subjecting a carbonaceous raw material substantially free of ash to at least one of the characteristics described above. (1) Flow initiation temperature is 200 ° C. or higher (2) Button index is 1 to 9 (3) Loga index is 30 to 90 (4) Optically anisotropic structure having a size of 30 μm or more is 30 ~
90% exists 2. The method according to claim 1, wherein the product obtained by the heat treatment has one or more of the following properties (1) to (3). Volatile content is 20% or less and 3% or more, and the amount of γ resin is 1 when measured by adjusting the average particle size to 15 to 20 μm.
0% or less and 1% or more 1 ton / cm ² The volumetric shrinkage rate is 10% or more when the rod-shaped molded product is fired up to 1000 ° C. 1 ton / cm ² molding pressure Bending strength is 200kg / cm when rod shaped body is fired up to 1000 ℃
^{Is 2} or more