JPS6050724B2 - Activated carbon manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing activated carbon having many pores with large pore diameters by a gas activation method for producing activated carbon.

The adsorption capacity of activated carbon depends not only on the total pore volume but also on the molecular size of the adsorbed substance and the activated carbon pore diameter.

In general, substances with large molecules to be adsorbed are well adsorbed on activated carbon having many pores with large pore diameters, and substances with small molecules to be adsorbed are well adsorbed on activated carbon having many pores with small diameters. Therefore, it is necessary to select activated carbon having pores of an appropriate diameter depending on the molecular size of the substance to be adsorbed. On the other hand, the pores of activated carbon are distributed over a wide range of diameters, from small to large, and the pore size distribution varies somewhat depending on the manufacturing conditions, but is largely dependent on the type of carbonaceous raw material, and is If the same raw materials are used in the method, only activated carbon with a fixed pore size distribution can be obtained. Therefore, in order to obtain activated carbon with a different pore size distribution, the raw materials must be changed each time. Furthermore, activated carbon obtained by gas activation generally has many small diameter pores distributed, and is not advantageous for adsorption of polymeric substances. The present inventors conducted various studies in view of these points, and found that by adding Ca, Na, and the like to the carbonaceous raw material, Ca and Na in the carbonaceous raw material were
The pore diameter of activated carbon can be increased by adjusting the absolute amount and ratio of Ca/
We have found a method for producing activated carbon with various pore size distributions using the same raw material by varying the Na+ ratio within a specific range.

That is, in the present invention, when producing activated carbon by activating a carbonaceous raw material using an oxidizing gas, one or both of a potassium compound and a sodium compound (first component) and a calcium compound ( 2nd component) to make the content of the first component and the second component in the carbonaceous raw material 0.5 to 1.5% by weight as metal, respectively, and as the metal of the first component and the second component. The weight ratio of
．． This is a method for producing activated carbon whose characteristic is to adjust so as to satisfy 0≧Me)1≧0.8.

The above-mentioned carbonaceous raw material may be any material that has been conventionally used as a raw material for activated carbon, such as bituminous coal, lignite, lignite, anthracite, charcoal, coconut shell coal, petroleum pitch, asphalt, etc. Among these, bituminous coal and coconut shell charcoal are preferably used.

The potassium compound, sodium compound, and calcium compound used in the present invention may be either an organic compound or an inorganic compound, and include potassium, sodium,
Low-molecular compounds, high-molecular compounds, or mixtures of various compounds that contain calcium, and in the case of organic compounds containing potassium, sodium, and calcium, each has a content of 0.
．． Any substance may be used as long as it contains at least 0.1% by weight, preferably at least 0.1% by weight, and in the case of inorganic compounds, at least 5% by weight.

JIS-K-0121 determines whether a polymer compound whose molecular weight cannot be specified or a mixture of various compounds contains the prescribed amounts of potassium, sodium, and calcium.
It can be measured by the method described in the general rules for atomic absorption spectrometry. Examples of the potassium compounds include inorganic potassium compounds such as potassium hydrogen carbonate, potassium carbonate, potassium borate, potassium phosphate, potassium chloride, potassium nitrate, potassium sulfate, potassium oxide, potassium hydroxide, potassium acetate, potassium oxalate, etc. Examples of sodium compounds include inorganic sodium compounds such as sodium bicarbonate, sodium carbonate, sodium borate, sodium phosphate, sodium chloride, sodium nitrate, sodium sulfate, sodium oxide, and sodium hydroxide. Examples include organic sodium compounds such as sodium acetate and sodium oxalate.

Examples of the calcium compounds include inorganic calcium compounds such as calcium carbonate, calcium borate, calcium phosphate, calcium chloride, calcium nitrate, calcium sulfate, calcium oxide, and calcium hydroxide, and organic calcium compounds such as calcium acetate and calcium oxalate. Examples include calcium compounds.

The above potassium compound, sodium compound, and calcium compound are added to the carbonaceous raw material as they are or dissolved in a suitable solvent such as water.

These are carbonaceous raw materials in which the total absolute amount of sodium and potassium in the first component and the second component and the absolute amount of calcium are respectively 0.5 to 1.5% by weight in the first component and the second component. It is added so that the weight ratio of metal in the metal satisfies 2.0≧crystalline≧0.8. Usually) carbonaceous raw materials originally contain sodium compounds and potassium compounds as metals (absolute amount of sodium, potassium) totaling 0.0
Contains about 1 to 1.0% by weight, and about 0.0001 to 0.1% by weight of calcium compounds as metals (absolute amount of calcium), and the amount added takes into account the existing content in the carbonaceous raw material. It can be decided by If the amount of the first component and the second component is less than the specified amount, the desired effect of the present invention cannot be obtained, and if the amount is more than the specified amount, the ash content in the activated carbon will increase, which is not preferable. Further, the desired effect of the present invention cannot be obtained when the ratio of the second component to the first component is smaller than the specified amount. In the present invention, as the ratio of the second component to the first component increases, the number of pores with a diameter of 200A or less in the obtained activated carbon increases, and conversely, as the ratio decreases, the diameter of the activated carbon increases. There is a tendency for many of the pores with a diameter of 200A or less to be small.
In the present invention, the first component and the second component may be added to the carbonaceous raw material within a specified range, and activated in the same manner as in the production method of activated carbon using a normal gas activation method. For example, water vapor, carbon dioxide gas, Usually 8006~ using an oxidizing gas such as oxygen gas or a mixture of three or more of these.
Activated at 1300°C. In the present invention, powdered charcoal,
It is possible to produce activated carbon in various forms such as granular charcoal, but when granular charcoal is produced, it is usually activated after adding a binding liquid to a carbonaceous raw material and granulating it.

In this case, part or all of the first component and the second component may be mixed with the binding liquid and added. In the activated carbon obtained by the method of the present invention, the pore volume with a pore diameter of 20 A or more accounts for about 50% or more (by methanol adsorption method) of the pore volume with a pore diameter of 200 A or less, and the activated carbon can be obtained by a conventional method. It has many pores with a larger diameter than activated carbon, and is therefore suitable for adsorbing adsorbed substances with large molecular weights, and is advantageously used for liquid phase adsorption, such as decolorizing raw sugar and tertiary treatment of municipal sewage.

EXAMPLES The present invention will be described in more detail with reference to Examples below.

In addition, in the following examples, sample No. 2, 3, 4 and 9 are activated carbons produced according to the present invention, and sample N
O. 1, 5, 6, 7 and 8 are control activated carbons.

Example 1. Bituminous coal (crushed product with 80% passing through 200 mesh) 1
Add 0 part of saliva, 1 part of caking valve waste liquid, and an aqueous solution (potassium carbonate and calcium chloride dissolved in 8 parts of water in the amounts shown in Table 1), and mix into 3 powders using a batch-type kneading machine. Knead.

The kneaded product is granulated into spheres of 12 to 16 mesh using a dish-type granulator using water as a binding liquid, and dried. The dried granules were put into a cylindrical rotary furnace with an inner diameter of 15mm and a length of 25h that rotates at a rotation speed of 1 rpm, and the temperature was increased from 300°C to 700°C at 51C/min while passing nitrogen gas at a rate of 51/min. The temperature is increased at a rate to remove volatiles and carbonize. The carbide is activated using the above rotary furnace under the following conditions. Activation gas: Steam activation temperature: 850'C Amount of carbide charged: 150 g Amount of steam supplied: 24 gr-H2O/100 da Carbide furnace rotation speed: 1 rpm Activation yield: 40 ± 1% (
Table 1 shows the pore volume and adsorption capacity of the activated carbon thus obtained.

In Tables 1 to 3 described in Examples, 1 potassium compounds, sodium compounds, and calcium compounds are each expressed in terms of metal amounts.

2 The pore volume was measured by the methanol adsorption method using an automatic adsorption amount measuring device (Tanaka Kagaku Kikai), and φ1, φ2, and φ3 indicate the pore volumes having pore diameters in the following range.

φ1: Pore volume with a diameter of 20 A or less φ2: Pore volume with a diameter of 20 to 50 A φ3: Pore volume with a diameter of 50 to 200 3 In the adsorption capacity test item, 1 yodo, RDBSj
．． ．． r Sugar solution refers to the following test method.

Iodine (Iodine adsorption power): JISK-1474 sample 0
．． 5gr' was placed in a 100rT11 stoppered flask, 50rr11 of N/10 iodine solution was added thereto, the mixture was shaken with a shaker, and then centrifuged.
Titrated with 0Na2S203, iodine adsorption power (M9/y)
Calculate. DBS (DBS adsorption power): Sample 30m9
200ppm DBS (sodium dodecylbenzenesulfonate) solution was added at 50rT11, shaken using a 1Br shaker, separated, and the remaining DBS concentration in the solution was reduced to 224ml.
It is measured from the absorbance of p, and the amount of adsorption is determined from the difference in concentration between the initial addition and the liquid, and the removal rate (%) is calculated.

Sugar solution (sugar solution decolorizing power): 150 m9 of crushed activated carbon was added to 50Brj 50n11 of molasses mixed sugar solution whose degree of coloration was defined by the decolorizing power value of standard activated carbon, and the mixture was heated at 80℃ in a constant temperature water bath for 1 hour.
After shaking for a period of time, measure the chromaticity.

Similarly, the amount of decrease in chromaticity is expressed as a percentage compared to the chromaticity treated without adding activated carbon.

Example 2. Activated carbon was obtained in the same manner as in Example 1 by adding sodium carbonate and calcium chloride in amounts shown in Table 2 to the bituminous coal used in Example 1.

The pore volume and adsorption capacity of the activated carbon obtained are shown in Table 2.

Example 3. Crushed coconut shell charcoal (250 mesh: 70%) 100
The caking valve waste liquid part used in Example 1 was added to the mixture, potassium carbonate and calcium chloride were added in the amounts shown in Table 3, and the mixture was kneaded for 30 minutes using a batch kneader.

Example 1 below. Granulate, carbonize and activate in the same manner as above to obtain activated carbon. The pore volume and adsorption capacity of the obtained activated carbon are
As shown in the table.

Claims (1)

[Claims] 1 When producing activated carbon by activating a carbonaceous raw material using an oxidizing gas, either one or both of a potassium compound and a sodium compound (first component) is added to the carbonaceous raw material.
and a calcium compound (second component) so that the content of the first component and the second component in the carbonaceous raw material is 0.5 to 1.5% by weight as metal, and the first component and the second component are The weight ratio of the components as metals is 2.0≧Ca/Na+
A method for producing activated carbon, characterized by adjusting the condition to satisfy K≧0.8.