JP2010280515A - Method for manufacturing activated carbon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide activated carbon having high adsorption ability and useful as an adsorbent, an electrode material of an electric double layer capacitor, and the like. <P>SOLUTION: A method for manufacturing the activated carbon is characterized in that polyvinyl alcohol is added to a dispersion of a spherical phenolic resin having an average particle diameter of 0.1-1 μm in an amount of 0.1-10 mass% based on the total amount of the phenolic resin and polyvinyl alcohol; they are mixed and freed of the liquid; the resulting spherical phenolic resin is coarsely crushed to an average particle diameter of ≥0.1 mm, carbonized and activated; and the resulting activated product is finely crushed to an average particle diameter of 0.1 to <1 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing activated carbon, and the activated carbon obtained by the method of the present invention can be used in a wide range of applications such as an adsorbent and an electrode material for an electric double layer capacitor.

  Conventionally, a multistage furnace, a rotary kiln, a fluidized bed, etc. are mentioned as a method of activating a carbon material. In order to perform uniform activation on the carbon material, a fluidized bed in which the contact area between the activation gas and the raw material can be increased, and a rotary kiln with stirring blades are relatively advantageous. However, the spherical phenol resin having an average particle size of 0.1 to 1 μm as used in the present invention has a defect that the particle size is small and it is difficult to activate in the prior art. For example, if the flow rate of the activation gas is increased with a rotary kiln, the yield of products decreases due to problems such as scattering of raw materials. Moreover, in a fluidized bed, since the raw material with a small particle size used by this invention cannot maintain a favorable fluidization state, there exists a fault that uniform activation cannot be performed.

  Therefore, in order to solve these drawbacks, a method is conceivable in which the material to be activated is granulated in advance and the particle size is increased. For example, in Patent Document 1, 0.1 to 1% by mass of pitch and polyvinyl alcohol (PVA) is added to a phenol resin having an average particle size of 1 μm or more and less than 20 μm, and granulated to 0.1 to 3 mm, and then activated. However, a technique for finely crushing to about 7 μm is disclosed.

  In Patent Document 2, polyvinyl alcohol (PVA) is added to a spherical phenol resin of 0.5 to 2,000 μm, granulated to 0.5 to 5 mm, activated and finely crushed to 1 to 10 μm. Techniques to do this are disclosed. In Patent Literature 3, granular phenol resin having an average particle diameter of 0.1 to 150 μm: PVA: 5 to 50 parts by mass are added to 100 parts by mass, granulated to about 1 mm, carbonized, and activated. A method has been devised, but fine disintegration is not described.

  Thus, in the prior art, the activated carbon, which is the final product, has a large particle size (1 μm or more), so that the adsorption performance (for example, methylene blue adsorption ability) is not sufficient.

JP 2007-131461 A JP 2001-143973 A Japanese Patent Laid-Open No. 9-11409

  The object of the present invention is to solve the above-mentioned problems of the prior art and to provide activated carbon having a high adsorptive capacity useful for an adsorbent, an electrode material of an electric double layer capacitor, and the like.

  The above object is achieved by the present invention described below. That is, in the present invention, 0.1 to 10% by mass of polyvinyl alcohol is added to a dispersion of spherical phenol resin having an average particle size of 0.1 to 1 μm with respect to the total amount of the phenol resin and polyvinyl alcohol. After mixing and draining, the obtained spherical phenol resin was coarsely crushed to an average particle size of 0.1 mm or more, carbonized and activated, and then the obtained activated product had an average particle size of 0.1 μm or more. Provided is a method for producing activated carbon, characterized by being finely pulverized to less than 1 μm.

  ADVANTAGE OF THE INVENTION According to this invention, activated carbon with high adsorptive ability useful for an adsorbent, the electrode material of an electric double layer capacitor, etc. (for example, methylene blue adsorption ability is 200 ml / g or more) can be provided.

Next, the present invention will be described in more detail with reference to preferred embodiments.
As the type of the phenol resin used in the present invention, a normal type such as a novolac type or a resol type can be used. Moreover, as a shape of the said phenol resin, the spherical thing whose average particle diameter is 0.1-1 micrometer is used. Spherical phenol resin is obtained by shaping the phenol resin into a spherical shape, and activated carbon having a large specific surface area can be obtained by activation. Therefore, the adsorption performance of the spherical activated carbon produced from this spherical phenol resin is more excellent. Become a thing. When the average particle size of the spherical phenol resin is smaller than 0.1 μm, handling is difficult, which is not preferable. On the other hand, when the average particle diameter of the spherical phenol resin exceeds 1 μm, the adsorption performance, for example, methylene blue adsorption ability is lowered, which is not preferable.

  Furthermore, since the spherical phenol resin is formed into a spherical shape unlike crushed coal, the spherical activated carbon obtained by the carbonization and activation thereof does not have an angular portion on the surface. For this reason, not only during transportation but also when used in a fluidized bed apparatus, there is little risk that the corners on the surface of the activated carbon particles are rubbed to produce fine powder. Therefore, there is no adverse effect on the apparatus due to the fine powder, and the fine pores on the surface of the activated carbon particles are not broken, and the adsorption performance and the like are not deteriorated.

  The addition amount of polyvinyl alcohol (PVA) mixed with the spherical phenol resin is 0.1 to 10% by mass with respect to the total amount of the phenol resin and polyvinyl alcohol. If the amount of PVA added is less than 0.1% by mass, the granulated shape cannot be maintained during carbonization / activation, the raw material is scattered, and the yield of the product is lowered. On the other hand, when the addition amount of PVA is more than 10% by mass, it is not preferable because it is too granulated and it is difficult to return to the average particle diameter of primary particles equivalent to the raw material phenol resin.

  The phenol resin and the PVA are preferably mixed in a liquid-liquid manner in order to uniformly mix them. Therefore, it is preferable to disperse the phenol resin in advance in a dispersion medium (for example, water), dissolve PVA in water as the dispersion medium, and stir and mix the two.

  After mixing and stirring, the medium (for example, water) is removed, and the resulting mixture is roughly crushed to an average particle size of 0.1 mm or more. Preferably, it is roughly crushed to an average particle size of 0.1 to 3 mm. If the particle size of the coarsely pulverized product is too small, the coarsely pulverized product is scattered during carbonization and activation. On the other hand, when the coarsely pulverized particle size is too large, handling becomes difficult.

  Next, the crude pulverized product is carbonized. As the carbonization method, an inert gas such as nitrogen, argon, helium, xenon, or neon and a mixed gas of two or more of these gases are used at 300 to 2,000 ° C., preferably 500 to 1,300 ° C. In the temperature range of about, a method of heating and carbonizing the crude crushed material for about 10 minutes to 30 hours is preferable.

  The activation method of the carbide is not particularly limited, and various known and usual activation methods can be used. For example, a gas activation method in which water, carbon dioxide (combustion gas), oxygen (air), or other oxidizing gas is brought into contact and reaction at a temperature of preferably 700 to 1,200 ° C., zinc chloride, phosphate, potassium hydroxide After impregnating an alkali metal compound such as sulfuric acid or an acid such as sulfuric acid, a chemical activation method by heating in an inert gas atmosphere preferably at a temperature of 300 to 800 ° C. is used. In the case of the chemical activation method, after activation, the product and the chemical used are generally neutralized with an acid or alkali, or removed using water washing or the like.

  In addition, as an apparatus which performs the said carbonization process and activation process, a multistage furnace, a rotary kiln furnace, a fluidized bed furnace etc. can be used, for example.

  After activation, the activated product is finely pulverized to an average particle size of 0.1 μm or more and less than 1 μm to obtain a desired activated carbon. If the average particle size of the activation product is too small, handling becomes difficult, while if the average particle size of the activation product is too large, the adsorption performance, for example, methylene blue adsorption ability is low (less than 200 ml / g).

  As the fine crushing method, a hammer mill, a ball mill, a jet mill, an atomizer or the like can be usually used, and is not particularly limited. Moreover, the obtained activated carbon can be classified and used.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In addition, this invention is not limited to a following example.
In the following, the average particle diameter of the coarsely pulverized activated carbon was determined by sieving. The average particle diameters of the phenol resin, the activated product, and the finely pulverized product were measured by dispersing them in water containing a surfactant using a laser particle size meter LMS-300 manufactured by Seishin Enterprise Co., Ltd.

  The BET specific surface area of the activated carbon was measured by ASAP2400 manufactured by Micromeritics. The measurement was performed according to the BET formula in the range of relative pressure P / P0 = 0.05 to 0.15 after vacuum drying at 200 ° C. to 1.33 kPa (10 mm Torr).

  The methylene blue adsorption ability of the activated carbon was measured according to JIS K1474 (2007).

[Example 1]
PVA with a solid content ratio of 0.1 part by mass is mixed with fine spherical phenol resin dispersion (solid content 99.9 parts by mass) with an average particle size of 0.60 μm, dehydrated, coarsely crushed, The crushed state was 0.2 mm. When the coarsely crushed product was carbonized at 700 ° C. and further steam activated at 800 ° C. in a rotary kiln, the yield was 53 mass%.

The above activated material was finely pulverized using a PJM-80SP jet mill manufactured by Nippon Pneumatic Co., Ltd. using a high-performance dust collector Excel filter. The BET specific surface area was 1,150 m ² / g and the methylene blue adsorption capacity 240 ml / g of spherical activated carbon was obtained. The spherical activated carbon had an average particle size of 0.58 μm and a crushing yield of 99% by mass.

[Example 2]
10 parts by mass of PVA was mixed with fine spherical phenol resin dispersion liquid (solid content 90 parts by mass) having an average particle diameter of 0.60 μm, dehydrated, and coarsely crushed into a crushed form with an average particle diameter of 0.2 mm. . The coarsely pulverized product was carbonized at 700 ° C., and further steam activated at 800 ° C. with a rotary kiln. The yield was 55% by mass.

When the activated product was finely pulverized, spherical activated carbon having a BET specific surface area of 1,180 m ² / g and a methylene blue adsorption capacity of 235 ml / g was obtained. The spherical activated carbon had an average particle size of 0.57 μm and a crushing yield of 99% by mass.

[Example 3]
3 parts by weight of PVA was mixed with fine spherical phenol resin dispersion liquid (solid content: 97 parts by weight) having an average particle diameter of 0.60 μm, dehydrated, and coarsely crushed into a crushed shape having an average particle diameter of 0.2 mm. . The crude pulverized product was carbonized at 700 ° C., and further steam activated at 800 ° C. in a rotary kiln. The yield was 54% by mass.

When the activated product was finely pulverized, spherical activated carbon having a BET specific surface area of 1,140 m ² / g and a methylene blue adsorption capacity of 253 ml / g was obtained. The spherical activated carbon had an average particle size of 0.56 μm and a crushing yield of 99% by mass.

[Example 4]
7 parts by mass of PVA was mixed with a fine spherical phenol resin dispersion (solid content: 93 parts by mass) having an average particle diameter of 0.60 μm, dehydrated, and coarsely crushed to obtain a crushed shape having an average particle diameter of 0.2 mm. . The coarsely pulverized product was carbonized at 700 ° C., and further steam activated at 800 ° C. with a rotary kiln. The yield was 55% by mass.

When the activated product was finely pulverized, spherical activated carbon having a BET specific surface area of 1,140 m ² / g and a methylene blue adsorption capacity of 242 ml / g was obtained. The spherical activated carbon had an average particle size of 0.57 μm and a crushing yield of 99% by mass.

[Comparative Example 1]
A spherical spherical phenol resin dispersion liquid (solid content 99.95 parts by mass) having an average particle diameter of 0.60 μm was mixed with 0.05 part by mass of PVA in a solid content ratio, dehydrated, roughly crushed, and average particle diameter The crushed state was 0.2 mm. The coarsely pulverized product was carbonized at 700 ° C., and further steam activated at 800 ° C. in a rotary kiln. The yield was 10% by mass.

When the activated product was finely pulverized, spherical activated carbon having a BET specific surface area of 1,180 m ² / g and a methylene blue adsorption capacity of 241 ml / g was obtained. The spherical activated carbon had an average particle size of 0.57 μm and a crushing yield of 99% by mass.

[Comparative Example 2]
11 parts by mass of PVA in a solid content ratio is mixed with a fine spherical phenol resin dispersion liquid (solid content 89 parts by mass) having an average particle diameter of 0.60 μm, dehydrated, and coarsely crushed. It was crushed. The coarsely pulverized product was carbonized at 700 ° C., and further steam activated at 800 ° C. in a rotary kiln. The yield was 10% by mass.

When the activated product was finely pulverized, spherical activated carbon having a BET specific surface area of 1,180 m ² / g and a methylene blue adsorption capacity of 233 ml / g was obtained. The spherical activated carbon had an average particle size of 6.5 μm and a crushing yield of 99% by mass.

[Comparative Example 3]
10 parts by mass of PVA in a solid content ratio is mixed with fine spherical phenol resin dispersion liquid (solid content: 90 parts by mass) having an average particle diameter of 0.60 μm, dehydrated, coarsely crushed, and an average particle diameter of 0.08 mm. It was crushed. The coarsely crushed product was carbonized at 700 ° C., and further steam activated at 800 ° C. in a rotary kiln. The yield was 8% by mass.

When the activated product was finely pulverized, spherical activated carbon having a BET specific surface area of 1,158 m ² / g and a methylene blue adsorption capacity of 231 ml / g was obtained. The spherical activated carbon had an average particle size of 0.58 μm and a crushing yield of 99% by mass.

[Comparative Example 4]
When the same operation as in Example 2 was performed except that fine crushing was not performed, the yield was 55% by mass. Further, spherical activated carbon having a BET specific surface area of 1,180 m ² / g and a methylene blue adsorption capacity of 135 ml / g was obtained. The spherical activated carbon had an average particle size of 200 μm and a crushing yield of 99% by mass.
The production conditions, activated carbon yield, and properties thereof are shown in the above examples and comparative examples.

  As shown in Table 1, Examples 1 to 4 according to the present invention have a higher activation yield than that of the comparative example, and the average particle size is the same as that of the fine spherical phenol resin as a raw material. It was confirmed that the activated carbon had a high adsorption capacity.

  The activated carbon produced by the production method of the present invention is useful in various industrial fields as an adsorbing material, an electronic material, an electric material, and the like.

Claims (1)

  To a dispersion of a spherical phenol resin having an average particle size of 0.1 to 1 μm, 0.1 to 10% by mass of polyvinyl alcohol is added to the total amount of the phenol resin and polyvinyl alcohol, mixed, and devolatilized. Then, the obtained spherical phenol resin was roughly crushed to an average particle size of 0.1 mm or more, carbonized, and activated, and the obtained activated product was finely pulverized to an average particle size of 0.1 μm or more and less than 1 μm. The manufacturing method of activated carbon characterized by crushing.