JPH061674A - Production of porous carbon material - Google Patents

Abstract

PURPOSE:To obtain a porous carbon material at a relatively low temp. in a high yield while easily regulating the physical properties by adding an acid- soluble inorg. compd. to pitches or raw cokes, heat-treating this mixture and treating the resulting product with an acid. CONSTITUTION:An acid-soluble inorg. compd. is added to pitches or raw cokes, this mixture is heat-treated and the resulting product is treated with an acid to obtain the objective porous carbon material. The carbonaceous starting materials used give <=10% fraction at <=300 deg.C, preferably 1-5% fraction at <=360 deg.C. The acid-soluble inorg. compd. is preferably a compd. of an alkaline earth metal such as the chloride, sulfate, carbonate or oxide of Ca, Ba or Mg, the carbonate or oxide is especially preferably used because it is easily treated, and the oxide, especially the oxide of Mg or Ca is most preferable.

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 porous carbon material. More specifically, the present invention relates to a method for producing a porous carbon material used as a gas or liquid adsorbing carbon material, a carbon material for a battery, or the like.

[0002]

2. Description of the Related Art In recent years, environmental problems such as water pollution and air pollution have been highlighted, and porous carbon materials such as activated carbon have attracted more and more attention. Removal of bacteria, odorous substances and chlorine compounds, which are said to be carcinogenic due to deterioration of water quality used for drinking water, cause of oxidant which is one of air pollution, and destruction of ozone layer of global environment A porous carbon material is used as one of pollution prevention measures such as removal of organic components in automobile exhaust gas, which is said to be one of the causes.

Porous carbon materials conventionally used for adsorption and removal of pollutants in water quality and atmospheric gas are activated in the presence of gas such as air and water vapor after calcination of plant fibers such as coconut shells and coal. Under the present circumstances, treatment is performed to increase the surface area and the amount of pores, and the characteristics of the porous carbon material are adjusted. Also,
With the rise in oil prices, the use of late-night power, and the development of communication systems, primary and secondary batteries have been rapidly reviewed and expanded, and the carbon materials used in batteries have come to attract attention accordingly. Therefore, various carbon materials, especially porous carbon materials, are attracting attention. Conventionally, as a carbon material for a battery, carbon black produced by thermally decomposing tar-based heavy oil or the like has been used.

[0004]

However, all of these porous high surface area carbonaceous powders must be treated at high temperature, and in some cases, activation treatment with a gas such as air or steam is required. The current situation is that the manufacturing cost is high. Further, since carbon is burned in a gas such as air or water vapor at a high temperature, there are problems such as low yield and difficulty in adjusting physical properties. There is also a demand for a small, light and efficient one for loading on an automobile or the like.

[0005]

In view of the above situation, the present inventors have made diligent studies, and as a result, after adding a specific inorganic compound to pitches or raw coke, heat treating this mixture,
It was found that when the heat-treated product is treated with an acid, a porous carbon material is easily produced, and the present invention has been completed. That is, the gist of the present invention is that, after adding an acid-soluble inorganic compound to pitches or raw cokes, heat treating the mixture, and then treating the resulting heat-treated product with an acid. There is a method for producing a high quality carbon material.

The present invention will be described in detail below. First, as pitches or raw cokes (hereinafter referred to as "carbonaceous raw material") used in the present invention, tar pitch produced by distillation of coal tar and heat treatment, petroleum heavy oil, and catalytic cracking oil thereof are used. Or distillation residual oils, heat-treated products such as hydrogenated cracked oils, pitches obtained by polycondensation of low molecular weight compounds such as naphthalene in the presence of a catalyst, and products subjected to solvent treatment (hereinafter, these are referred to as “pitches”). (Collectively),
Also, raw coke or the like obtained by heat-treating them at 300 to 500 ° C. for 1 to 48 hours in an autoclave, a delayed coker or the like is used as a raw material.

The carbonaceous raw material used in the present invention is usually 30
It is suitable that the fraction at 0 ° C or lower is 10% or less, preferably the fraction at 360 ° C or lower is 10% or less, and most preferably the fraction at 360 ° C or lower is 1 to 5%. The acid-soluble inorganic compound is preferably an alkaline earth metal compound, and examples thereof include chlorides such as calcium (Ca), barium (Ba), and magnesium (Mg), sulfates, carbonates, and oxides. Although it can be used, carbonates and oxides are preferable because they are easily treated.
Oxides are particularly preferable, and oxides of magnesium and calcium are most preferable.

[0008] The addition amount is 1 by weight ratio to the carbonaceous raw material.
/ 1 or more (= inorganic compound / carbonaceous raw material) is preferable, 55/45 to 95/5 is more preferable, and 60/40 to 90/10 is most preferable. As a method of addition, a carbonaceous raw material and an acid-soluble inorganic compound are preferably blended in the form of powder. Further, in the case of pitches, it is also possible to heat and melt it into a liquid state and blend the inorganic compound with it.

Further, the carbonaceous raw material may be dispersed or dissolved in a solvent and mixed in the solvent, or raw coke may be dispersed in the solvent and mixed. The heat treatment of the mixture is preferably carried out at 150 ° C. or higher for 0.5 to 24 hours, more preferably at 180 to 350 ° C. for 0.5 to 10 hours, and most preferably at 200 to 300 ° C. for 0.5 to
It is good to do it for 5 hours.

Further, the heat-treated product has a higher temperature (350 to
It can also be baked at 1000 ° C., and the volatile matter can be removed if necessary. The pressure during the heat treatment is usually atmospheric pressure, but it can be performed under high pressure. The atmosphere can be treated in an inert gas, in the presence of oxygen, or in coke breeze, but it is preferable that oxygen is present, and the oxygen concentration is 5 to 5
It is also possible to adjust and process to 0%.

The treated product thus obtained is, if necessary, pulverized and then treated with 5 to 35% of an inorganic acid such as hydrochloric acid or sulfuric acid.
Alternatively, the product can be obtained by treating with 5 to 50% of an organic acid such as acetic acid to dissolve and remove the inorganic compound, but as the acid, the inorganic acid has a strong dissolving power and is advantageous. The dissolution may be carried out at room temperature, but in order to accelerate the dissolution, high temperature (50-
You may perform it at 100 degreeC.

Further, the heat-treated product and the acid may be mixed and treated in a batch, but it is also possible to perform the treatment continuously while circulating the acid. The product obtained by the acid treatment can be further calcined and graphitized if necessary. The carbonaceous material thus obtained usually has an average particle size of 50 μm.
The following is preferably 0.1 to 30 μm and has a surface area of 1
Porous carbon powder having a particle size of 00 m ² / g or more, and further 50
It becomes a porous carbon powder of 0 to 2000 m ² / g or more and is used for purification of water quality, treatment of harmful substances in atmospheric gas, and the like. Hereinafter, the present invention will be described in more detail with reference to Examples.

[0013]

【Example】

Example-1 Commercial Impregnated Pitch and Commercial Magnesia (MgO) Powder 3
After mixing 0/70 (weight ratio) in a powder state, heat treatment was performed in air at 250 ° C. The heat-treated product was immersed in hydrochloric acid diluted with concentrated hydrochloric acid 10 times at room temperature for one day and then washed with hydrochloric acid and dried to obtain a product. The average particle size of the product was 20 μm and the surface area was 700 m ² / g.
When the produced porous carbonaceous powder was observed with a scanning electron microscope, the shape of the holes was a honeycomb structure.

[0014]

According to the present invention, a porous high surface area carbonaceous material can be easily produced at a relatively low temperature, physical properties can be easily adjusted, and a high yield can be obtained.

Claims (1)

[Claims] 1. A porous carbonaceous material characterized in that an inorganic compound soluble in an acid is added to pitches or raw coke, and then this mixture is heat-treated, and then the heat-treated product obtained is treated with an acid. Material manufacturing method.