JPS58110412A - Manufacture of granular activated carbon from waste powdered activated carbon as starting material - Google Patents

Abstract

PURPOSE:To manufacture inexpensive granular activated carbon of high performance by regeneration while preventing scattering during heating by well mixing waste powdered activated carbon with bentonite and an inorg. adhesive, molding the mixture, and calcining the molded body. CONSTITUTION:Waste powdered activated carbon (A) is well mixed with bentonite (B) and an inorg. adhesive (C) such as a cement type silicate compound in (40-70):(5-30):(10-50) dry weight ratio of A:B:C. The mixture is molded into a spherical shape having 1mm. diameter and calcined at >=500 deg.C to manufacture granular activated carbon. Scattering during heating can be prevented by the granulation. When an org. adhesive is used, the hardness of the resulting granular activated carbon is reduced remarkably by regeneration under heating, and the adsorbing power is not sufficiently restored. An inorg. adhesive does not cause said defects but makes molding difficult. By combining the inorg. adhesive with bentonite, the problem is settled.

Description

DETAILED DESCRIPTION OF THE INVENTION Currently, approximately 50,000 tons of powdered activated carbon is used annually, mainly in the food industry. Used waste activated carbon powder becomes waste activated carbon and is difficult to recycle, so most of it is disposed of in landfills. Recently, it has become increasingly difficult to secure land for landfills, and post-treatment of waste activated carbon powder has become an issue.

As shown in Table 1, the adsorption power of the waste activated carbon powder remains considerable, and regeneration itself to restore the adsorption power is relatively easy. However, highly activated carbon usually contains more than 50% water. When thermal regeneration is performed, water vapor is generated in the equipment, which scatters fine activated carbon powder, making it difficult to regenerate large μ on a commercial basis.

Therefore, in order to prevent the scattering during heating, which is a problem when recycling waste activated carbon powder, we granulated waste activated carbon powder to make the recycling process easier, and at the same time, we investigated an inexpensive method for producing granular activated carbon.

We added various adhesives to waste powdered activated carbon, granulated it, fired it, measured the performance of the resulting granular activated carbon, and searched for adhesives that can produce high-performance, inexpensive granular activated carbon. .

It has been found that organic adhesives have problems, such as when the obtained granular activated carbon is heated and regenerated, the hardness of the particles is significantly reduced, or the recovery of adsorption power is insufficient.

Although inorganic adhesives do not have the above-mentioned problems encountered with organic adhesives, there are still issues to consider, such as difficulty in molding or the inability to mold without adding a large amount of adhesive.

In this study, we searched for additives to improve moldability and investigated the molding of waste activated carbon powder using an inorganic adhesive.

As a result, it was possible to mold waste activated carbon powder using bentonite as an additive and a so-called cement-based silicate compound as an inorganic adhesive.

In addition, the molded products were fired at various temperatures and the adsorption force of the fired products was measured. As a result, it was found that most of the adsorption force can be recovered by firing at a temperature of 500°C or higher.

Bentonite and silicate compounds are inexpensive substances, and the regeneration treatment involves short-time firing at 500° C. or higher, so the granular activated carbon produced by the above production method is economical.

Example Waste powder activated carbon, bentonite and silicate compound were mixed well in a ratio of 60:/3:23 (dry weight),
Water was added to this in a ratio of 70 and mixed. Diameter of the mixture/
It was molded into a spherical shape. After drying the spheres at 700'C,
Spherical activated carbon was obtained by heating for 30 minutes. The various performances of this spherical activated carbon were as follows.

Bulk specific gravity 0.55 Specific surface area 750♂t Caramel decolorizing power 7q Hardness 9.20g Caramel decolorizing power was measured according to JIS Kl 470-1967. Moreover, the hardness is the average value of 20 particles at the pressure at which 7 particles are destroyed.

[Brief explanation of drawings]

Table 1 shows the physical properties of the waste activated carbon powder, and the items were measured according to JISKI470-1967. In addition, the ash content in the item is the residue when the solid content is taken as 100. Procedural amendments S. 70, 1982 1, Case description 1982 Patent No. 214830 2
, Hatsuro's name: 3. Relationship with the case of the person making the amendment Patent applicant 4, date of amendment order 9, 1980 5, drawings and specification subject to amendment 6, statement of contents of amendment 1, name of invention: waste powder activated carbon A method for producing granular activated carbon as a raw material. 2. Claims Waste powder activated carbon, bentonite and inorganic adhesive
The mixture was well mixed in the ratio of IO~70:5~30:10~50 and then fired (temperature = s o o”c
A manufacturing method for producing granular activated carbon by the above). 3. Detailed Description of the Invention Currently, around 50,000 tons of powdered activated carbon is used annually, mainly in the food industry. Unlike waste granular activated carbon, used waste activated carbon powder is difficult to regenerate, and most of it is disposed of in landfills. Recently, it has become increasingly difficult to secure land for landfills, and post-treatment of waste activated carbon powder has become an issue. As shown in Table 1, the adsorption power of the waste activated carbon powder remains considerable, and the regeneration itself to restore the adsorption power is relatively easy, but normally open activated carbon contains more than 50% water. When performing heat regeneration, a large amount of water vapor is generated, which scatters fine activated carbon powder, making it difficult to regenerate large quantities on a commercial basis. Table 1 Physical properties of waste activated carbon powder 1) Measured according to JIS K 1470-1967. 2) Residue with solids content as /DO. Therefore, in order to prevent the scattering during heating, which is a problem when recycling waste activated carbon powder, we granulated waste activated carbon powder to make the recycling process easier, and we also investigated a method for manufacturing inexpensive granular activated carbon. Various adhesives were added to waste powdered activated carbon, granulated, and fired, and the performance of the resulting granular activated carbon was measured to search for an adhesive that can produce high-performance, inexpensive granular activated carbon. It has been found that organic adhesives have problems in that when the obtained granular activated carbon is heated and regenerated, the hardness of the particles becomes extremely small, or the recovery of adsorption power is insufficient. Inorganic adhesives do not have the above-mentioned problems that occur with organic adhesives, but there are issues to consider such as difficulty in molding or the inability to mold without adding a large amount of adhesive. In this study, we searched for additives to improve moldability and investigated the molding of waste activated carbon powder using an inorganic adhesive. As a result, it was possible to mold waste activated carbon powder using bentonite as an additive and a so-called cement-based silicate compound as an inorganic adhesive. In addition, the molded products were fired at various temperatures and the adsorption force of the fired products was measured. As a result, it was found that most of the adsorption power was recovered by firing at a temperature of 300°C or higher. Bentonite and silicate compounds are inexpensive materials, and the regeneration process involves short-time firing at temperatures above 5-00"C, so the granular activated carbon produced by the above production method is economical. Examples Waste powder activated carbon, bentonite and silicate compound were mixed well in a ratio of 0:/S:25 (dry weight), and water was added and mixed in a ratio of 70.The mixture was mixed in a diameter/m
It was molded into a spherical shape of m. After drying the spheres, 700'C, 30
After heating for a minute, spherical activated carbon was obtained. The various performances of this spherical activated carbon were as shown in Table 2. Table 2 Performance of spherical activated carbon Caramel decolorizing power is JIS K 1470-1967
Measured according to Moreover, the hardness is the average value of 20 particles at the pressure at which 7 particles are destroyed. Patent applicant: Toshiyuki Nakajima, Nakajima Chemical Industry Co., Ltd.

Claims (1)

[Claims] A mixture of waste activated carbon powder, bentonite, and inorganic adhesive in a ratio of 70:5 to 30:70 to 50 is molded and then fired (temperature = 500°C or higher).
A manufacturing method for producing granular activated carbon by