JP2000197867A - Decomposition of dioxins in solid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decompose dioxins contained in a solid (incineration fly ash, inciner ation ash or soil) by a simple method without consuming much energy. SOLUTION: Water 3 is added to a solid 2 containing dioxins and 0.1% or more by wt. of the solid of ferrous sulfate 4 is added to the solid in terms of Fe while the solid is kneaded or stirred along with water in a wet state or a slurry state and, subsequently, 1-10 wt.% or more of hydrogen peroxide 5 is added to the resulting slurry in terms of H2O2 to decompose dioxins in the solid. Herein, the decomposition of deoxins can be performed at the normal temperature-100 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decomposing dioxins in solids, and more particularly to dioxins in solids which oxidatively decompose dioxins contained in solids such as incinerated fly ash, incinerated ash and soil. And a method for disassembling.

[0002]

2. Description of the Related Art Conventionally, a method for decomposing dioxins in a solid is a method of heating under a high temperature condition of about 1200 ° C. or more by the heat of combustion of fuel or heat energy obtained from electricity, as in a melt solidification method. The organic matter in the material to be melted is thermally decomposed, gasified, and burned, and the inorganic matter is made into a molten state, and then cooled and solidified into slag, or treated under heat-deficient oxygen conditions, as in the heat dechlorination method. After heating the product to about 400 ° C., it is quenched to 200 ° C. or less in order to suppress resynthesis. These methods have the problems that the initial cost of the apparatus is high and that a large amount of heat energy is required for heating.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and reduces dioxins contained in solids (incinerated fly ash, incinerated ash, soil, etc.) by a simple method and greatly. It is an object of the present invention to provide a method for decomposing dioxins in a solid, which can be decomposed without consuming much energy.

[0004]

In order to solve the above-mentioned problems, in the present invention, water is added to a solid containing dioxins, and ferrous sulfate is added to the solid while kneading or stirring in a wet state or a slurry state. 0.1wt per Fe conversion
% Or more, and then aqueous hydrogen peroxide is added to the solids based on H
_A method for decomposing dioxins in a solid, characterized in that dioxins are decomposed by adding 1 to 10 wt% in terms of ₂ O ₂ . In the decomposition method, the decomposition of the dioxins can be performed at a temperature of from room temperature to 100 ° C. As described above, ferrous sulfate as a catalyst is effective at 0.1 wt% or more in terms of Fe per solid, and H ₂ O ₂ as an oxidizing agent is 1 wt% in terms of H ₂ O ₂ per solid.
Was effective. The more H ₂ O ₂ is added, the more effective it is, but from the viewpoint of cost, 10% or less is appropriate.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention decomposes dioxins contained in solids (incineration fly ash, incineration ash, soil, etc.), so that ferrous sulfate is used as a catalyst in an amount of 0.1% in terms of Fe per object. At least 1% is added, and then hydrogen peroxide solution is added as an oxidizing agent to oxidatively decompose dioxins contained in the solid. The above reaction is carried out in a wet or slurry state by adding water and kneading or stirring, but the kneading method and stirring method are not limited, and any known method can be used. According to the present invention, in solid (incineration fly ash, incineration ash,
The mechanism by which dioxins contained in soil and the like are decomposed is unknown, but in the case of oxidation with hydrogen peroxide,
The reaction was promoted by the addition of iron in 1899 HJH
Found by Fenton (called Fenton's reagent)
However, experiments have shown that the present invention can also decompose dioxins that are difficult to decompose at room temperature.

[0006]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. Example 1 FIG. 1 shows a processing flow chart for implementing the method for decomposing dioxins of the present invention. As shown in FIG. 1, in the present invention, an object to be treated (solid) 2, water 3, ferrous sulfate heptahydrate 4, and hydrogen peroxide 5 are put into a kneader and kneaded while stirring. Thus, the processed product 6 in which the dioxins are decomposed can be obtained without requiring other means such as heating and the like. According to FIG. 1, shredder dust (combustible debris generated when a car is cut) is burned at a high temperature in a gasification and melting furnace plant as an object to be processed (solid), and a bag filter ash generated when melted and solidified is removed. Was carried out. Table 1 shows the composition of the collected ash.

[0007]

[Table 1] 20% slaked lime was added to the bag filter collected ash having the composition shown in Table 1.
While adding ash and kneading, ferrous sulfate heptahydrate dissolved by adding 3 times the weight of water to this was dissolved at 2% / Fe.
Ash was added, then 30% H ₂ O ₂ was added at 3% / ash per 100% H ₂ O ₂ and reacted for 1 hour without heating. The dioxin concentration after the treatment was 0.011 n in terms of dry matter.
g-TEQ / g.

Example 2 Slaked lime was added to the ash collected in the bag filter of Example 1 in an amount of 20% / ash and kneaded, and ferrous sulfate / 7 hydrate was added to water 2
The solution dissolved by adding twice the weight was added at 2% / ash in terms of Fe, and then 15% H ₂ O ₂ was added at 3% per 100% H ₂ O _2.
% / Ash was added and reacted for 1 hour in a heating state at 70 ° C. The dioxin concentration after the treatment was reduced to 0.008 ng-TEQ / g in terms of dry matter.

Example 3 Next, a fluid bed type municipal solid waste incinerator bag filter collected ash was used as an object to be treated (solid). Table 2 shows the composition of the collected ash.

[Table 2] The fermented sulfate heptahydrate added to twice the weight of water and dissolved in the bag filter collected ash having the composition shown in Table 2 was converted to Fe by 2%.
% / Ash added, then 15% H ₂ O ₂ is replaced with 100% H ₂ O ₂
3% / ash was added, and the reaction was carried out at room temperature for 1 hour.
The dioxin concentration after the treatment is 0.1% in terms of dry matter.
It was reduced to 7 ng-TEQ / g.

Example 4 Ferrous sulfate heptahydrate dissolved in a soil containing dioxins in an amount of 0.22 ng-TEQ / g was added twice as much as water, and 2% ash was added in terms of Fe. , Then 15% H
₂ O ₂ was added in an amount of 3% / ash per 100% of H ₂ O ₂ and reacted for 1 hour at room temperature. The dioxin concentration after treatment is
It was reduced to 0.056 ng-TEQ / g in terms of dry matter.

[0011]

As described above, in the conventional method, the decomposition of dioxins contained in a solid (incineration fly ash, incineration ash) is performed by a method of decomposing at a high temperature such as a melt solidification method and a heat dechlorination method. However, in the present invention, dioxins contained in solids (incineration fly ash, incineration ash, soil, etc.) can be decomposed at a low temperature of room temperature to 100 ° C., and the initial cost is low, The handling was easy, and the heat energy was very small compared with the conventional method.

[Brief description of the drawings]

FIG. 1 is a processing flowchart for implementing a decomposition method of the present invention.

[Explanation of symbols]

1: kneader, 2: processed object (solid), 3: water, 4: Fe
_{SO 4 · 7H 2 O, 5} : H 2 O 2, 6: treated

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Claims (2)

[Claims] Claims 1. Water is added to a solid containing dioxins,
Kneading or stirring in a wet state or a slurry state, was added over 0.1 wt% of ferrous sulfate in the solid per terms of Fe, then 110 wt.% Aqueous hydrogen peroxide in the solid per H ₂ O ₂ conversion A method for decomposing dioxins in a solid, the method comprising decomposing dioxins by addition. 2. The decomposition of dioxins is carried out at room temperature to 1
The method for decomposing dioxins in a solid according to claim 1, wherein the method is carried out at a temperature of 00 ° C.