JPH03279208A - Production of formed product of active carbon - Google Patents

Abstract

PURPOSE:To obtain a formed product of active carbon, excellent in active carbon function with a high strength and good in handleability by carrying out baking treatment of an organic binder at least carbonizable by baking and active carbon having fine powder of silicic acid anhydride applied to the surface thereof as a principal material. CONSTITUTION:An organic binder (e.g. an acrylic resin, melamine resin or PVC) at least carbonizable by baking and active carbon are used as a principal material and subjected to baking treatment to produce a formed product of the active carbon. In the process, active carbon prepared by preapplying fine powder of silicic acid anhydride to the surface thereof is used as the aforementioned active carbon. The fine powder of the silicic acid anhydride applied to the surface of the active carbon is mutually fused on the surface of the active carbon by treatment at a high temperature and a cellular structure is simultaneously provided. Thereby, strength as the formed product of the active carbon is increased and gas permeability required for the active carbon function is also simultaneously ensured. The formed product can be suitably used as, e.g. filters and catalyst carriers.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing activated carbon molded articles that are required to have activated carbon functions and gas permeability, and are used, for example, in filters, catalyst carriers, and the like.

(Prior Art) Various methods are known for manufacturing an activated carbon molded article by using at least an organic binder that is carbonized by firing and activated carbon as main materials and performing a firing treatment. The shapes that can be obtained are various, such as particulate.

(Problems to be Solved by the Invention) Compared to activated carbon in the form of a powder, activated carbon in the form of particles can be easier to handle. However, if an attempt is made to make use of the activated carbon present inside to make it functionally superior, the product will be inferior in strength and cannot fully demonstrate its advantages in handling.

- An example is the case of hollow activated carbon moldings. The hollow activated carbon molded product is made of the above-mentioned organic binder and activated carbon, with particulate matter that is dissipated and consumed at a temperature higher than the temperature at which the organic binder starts to decompose and carbonized as a core material, and has a surface that is hard to age. It can be obtained by performing a firing process. and,
Because it is hollow, it has a similar external shape compared to a product obtained by simply using an organic binder and activated carbon as the main materials, kneading it, molding it, and then firing it. However, the activated carbon has excellent functionality. However, the strength is extremely low, and it depends on the size and degree of hollowness.
It may even become something that can be easily crushed with your fingertips.

Therefore, the present invention is applicable to the case where a hollow activated carbon molded article is obtained by using the above-mentioned core material.

The purpose of the present invention is to provide a method for producing a molded product with excellent activated carbon functionality, which greatly suppresses a decrease in strength without having almost any adverse effect on improving the functionality.

(Means for Solving the Problems) The present invention uses at least an organic binder that is carbonized by firing and activated carbon as main materials, and when performing firing treatment to produce an activated carbon molded product, the activated carbon is preliminarily filled with silicic anhydride. The gist of the present invention is a method for producing an activated carbon molded article, which is characterized in that the activated carbon molded article is coated with a fine powder of.

The details will be explained below. In addition, as a means of improving functionality.

There is a method of obtaining a mixed material containing a pore-forming material dispersed therein and firing it to make it have a large porosity, but in view of the above, we will discuss the case of creating a hollow material. .

First, activated carbon can be used as appropriate regardless of the raw materials or manufacturing method. During the firing process, activated carbon may be used, and the size is appropriate, but if it is up to about 200 μm, it will have excellent uniformity.

Fine powder of silicic anhydride is applied to the surface of this activated carbon. Colloidal silica, which is commercially available as a colloidal aqueous solution of silicic anhydride, may be used. Commercially available products include, for example,
Examples include ``Snowtex'' (manufactured by Nissan Chemical Industries, Ltd.) and ``Ludox'' (manufactured by DuPont). In addition, products made by Monsando are also on sale. It can also be used after being diluted to an appropriate concentration.

It is easy to soak activated carbon in these, remove the excess, and then dry by air drying or heating. Here, appropriate impregnation such as heat impregnation and vacuum impregnation can be performed.

In addition, organic binders include natural and synthetic resins, rubber,
A variety of thermosetting initial condensates, pitch, tar, asphalt, etc. can be selected - examples include styrene resin, acrylic resin, urea resin, melamine resin, polyester resin, furan resin, polyvinyl alcohol, polyacrylamide, butyl rubber, chlorinated Examples include polyethylene, polyvinyl chloride, polyvinylidene chloride, etc. They may be used alone or in combination of two or more.

Activated carbon coated with fine powder of silicic anhydride, an organic binder, and stabilizers used as necessary are applied to the core material, which is dissipated and consumed at a temperature above the temperature at which the organic binder starts to decompose and carbonize. Get something that has become a thing. The size is appropriate, for example, relatively small for household/personal use such as deodorizing refrigerators and drinking water filters, and relatively large for large-scale use such as factory exhaust. However, in general, 0. It is best to choose between a few and a dozen temples.

Here, examples of core substances include various inorganic salts such as carbonates, nitrates, sulfates, and phosphates, polyethylene, polypropylene, polybutadiene, polyisobutylene, polystyrene, polymethmethylstyrene, polymethyl methacrylate, and polymethacrylate. Examples include depolymerizable organic substances such as ethyl acid, polyacrylic ester, poly-α-toiterostyrene, and nylon. These are appropriately selected and used depending on the type of organic binder. However, in many cases, shrinkage of the molded product due to decomposition and carbonization of the organic binder almost ends at about 300°C, so it is generally preferable to use a material that does not cause much dissipation and consumption up to about 300°C. Examples that satisfy this condition include polyethylene, polymethyl methacrylate, polyacrylic ester, and nylon. In addition, when attaching to the core material, a ball mill, a sand mill, a mixer roll mill, a kneader, etc. are used, or an encapsulation method using a hybridization system, which is a mechanochemical method that has been attracting attention in recent years, is used. Bye.

Incidentally, if the size of the core material is 5 times or more larger than that of activated carbon, the adhesion properties will generally be improved.

In addition, when applying the activated carbon and the organic binder, it is possible to treat the activated carbon and the organic binder at the same time, or apply the organic binder first and then apply the activated carbon, as appropriate. can. Furthermore, the material applied to the core material in this manner can be reapplied to the core material as treated activated carbon. By the way.

How much organic binder and activated carbon should be applied to the core material?

If the amount is relatively small, the larger the amount, the better the activated carbon function.
It has excellent strength. Further, when the adhesive is attached by dry processing without using a solvent or the like, the degree of fixation is generally high if the sum of the weights of the activated carbon and the organic binder is limited to about 60 parts of the core material.

The obtained particulate material is subjected to a firing treatment to carbonize the organic binder. It may be dried in advance if necessary. The heating rate is determined with consideration to the occurrence of cracks and swelling. The maximum temperature depends on the processing atmosphere, such as an inert gas atmosphere, a reducing atmosphere, or a vacuum atmosphere, but is usually between 700 and 110℃.
The temperature is about 00°C, preferably about 800 to 1000°C. After performing a relatively low-temperature treatment up to about 700''C, it is also possible to change the atmosphere and perform the treatment again.After this high-temperature heat treatment, an activation treatment or the like is performed as necessary.

In addition, other adsorbents such as silica gel and zeolite, antibacterial substances such as silver, etc. can also be used in combination as materials used.

(Function) The fine powder of silicic anhydride deposited on the surface of the activated carbon fuses with each other on the surface of the activated carbon and forms a porous structure by high temperature treatment. This increases the strength of the activated carbon molded product and also ensures the gas permeability necessary for the activated carbon function.

(Example) Hereinafter, parts simply refer to parts by weight.

<Example 1> (1) 20 parts of activated carbon-treated Kuraray Coal PK (powdered activated carbon manufactured by Kuraray Chemical ■, particle size of 200 mesh or less) was mixed with Snowtex 20 (colloidal silica: silicic anhydride; particles manufactured by Nissan Chemical Industries ■) After immersing in 40 parts (diameter: 10-20 mμ, content: about 20%), the mixture was filtered and separated to remove the excess, and the obtained product was heated and dried at 110°C.

(2) Production of hollow activated carbon molded product 40 parts of flow beads CL-5007 (true spherical polyethylene manufactured by Sumitomo Seika Chemicals, particle size range 250 to 500 μm),
Polyvinyl chloride resin (manufactured by Denki Kagaku Kogyo ■: particle size range 20)
The mixture was mixed for about 1 hour with 10 parts of the activated carbon prepared in (1) for about 1 hour, and 15 parts of the activated carbon prepared in (1) was added thereto and mixed for an additional 1 hour. After removing excess activated carbon and polyvinyl chloride resin, the temperature is raised in air from room temperature to 300°C at a rate of about 5°C/min, and then placed in a sealed container and heated to a maximum temperature of 8°C.
A firing treatment was performed at 00°C for 1 hour.

<Example 2> In Example 1, Snowtex 40 (colloidal silica, silicic anhydride, particle size 10 to 20 mμ, content approximately 40%, manufactured by Nissan Chemical Industries, Ltd.) was used instead of Snowtex 20.
Everything was the same as in Example 1 except that .

<Example 3> Everything was the same as in Example 1 except that Snowtex 20 was diluted twice with water.

<Example 4> In Example 1, instead of Snowtex 2o, Snowtex 20L (colloidal silica manufactured by Nissan Chemical Industries ■: silicic anhydride; particle size 40 to 50 mμ, content approximately 20
%) was used as in Example 1.

<Example 5> In Example 1, instead of the ball mill treatment, 40 parts of Flow Beads CL-8007 (true spherical polyethylene manufactured by Sumitomo Seika Chemicals Ltd., particle size range 500-850 μm) was mixed with polyvinyl chloride resin (Sumitomo Chemicals Ltd.). Made: Particle size range 50~8゜μ
m) After processing with 10 parts using a hybridization system (manufactured by Nara Kikai Seisakusho) at 8000 rpm for 5 minutes, add 15 parts of the activated carbon prepared in (1) to this and further at 800 Qrpm for 5 minutes. Everything was the same as in Example 1 except that the treatment was carried out under the following conditions.

<Example 6> In Example 5, 40% of flow beads CL-8007 were treated with the hybridization system.
The same procedure as in Example 5 was repeated except that 5 parts of the polyvinyl chloride resin and 8 parts of the activated carbon prepared in (1) were alternately treated twice.

<Example 7> In Example 15, as a treatment by the hybridization system, 10 parts of polyvinylidene chloride resin (manufactured by Kureha Chemical Industry Co., Ltd.: particle size range 50 to 100 μm) and (1
) and 15 parts of the prepared activated carbon were first treated and integrated, and then treated with 40 parts of Flow Beads CL-8007, but everything was the same as in Example 5.

<Comparative Example 1> In Example 1, in place of the activated carbon prepared in (1), (
Everything was the same as in Example 1 except that activated carbon without treatment in 1) was used.

<Comparative Example 2> 28 parts of polyvinyl chloride resin (described above) and Tararecol PK
After mixing 35 parts and 10 parts of dioctyl phthalate (plasticizer) in a kneader for about 30 minutes, it was mixed with 500 parts in diameter in a granulator.
m particulate matter was obtained, and the same firing treatment as in Example 1 was performed on this particulate matter.

Table 1 shows the evaluation results obtained on each side. Note that the specific surface area was measured by the BET method. In addition, the adsorption capacity is based on the methylene blue decolorization capacity according to JIS K 147.
Measured according to 0. In addition, the strength is evaluated by the number of crushes when crushed with fingers. 0: Crush rate less than 10%, ○: Crush rate 10% or more to less than 30%, Δ: Crush rate 30
% or more and less than 50%, ×: collapse rate is 50% or more.

(Effects of the Invention) As described above, according to the present invention, the activated carbon has excellent functionality,
In addition, it is possible to produce an activated carbon molded product that is strong and sufficiently easy to handle.

Claims (1)

[Claims] When producing an activated carbon molded article by using at least an organic binder that is carbonized by firing and activated carbon as main materials and performing a firing treatment, fine powder of silicic anhydride is applied to the surface of the activated carbon in advance. 1. A method for producing an activated carbon molded article, characterized by using a molded article of activated carbon.