JP2003311122A - Composite flue blow-in chemical agent and usage therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment agent for exhaust gas and soot for neutralizing acidic gas discharged from an incinerator, fixing harmful heavy metals in fly ash to satisfy a landfilling elution standard, and a usage therefor. <P>SOLUTION: A composite flue blow-in chemical agent is prepared by uniformly mixing 3.01-11.54 pts.wt. of aluminum hydroxide and/or active alumina (γ-Al<SB>2</SB>O<SB>3</SB>) with a mean particle size of 10-45 μm with 100 pts.wt. of calcium hydroxide with a specific surface area of 30 m<SP>2</SP>/g or more. When this chemical agent is blown in a flue held to a temperature range of 110°C or higher, it is mixed with soot at the same time and dust is collected in this state and subsequently humidified and kneaded in advanced kneading equipment to be used. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to composite flue insufflation agents and methods of use thereof. More specifically, hydrogen chloride (HCl) and acidic sulfur oxides (S) generated from incinerators
Ox) and other acidic exhaust gas are neutralized, and stabilization treatment of harmful heavy metals contained in fly ash is started, and after induction with advanced fly kneader along with fly ash, hydro-kneading treatment is performed. The present invention relates to a composite flue blowing agent capable of preventing elution of harmful heavy metals from fly ash after kneading treatment and a method of using the same.

[0002]

2. Description of the Related Art In a refuse incinerator, although there are some differences depending on the components of the refuse to be burned, the incineration conditions, the structure and characteristics of the incinerator, plastics and salt containing chlorine such as vinyl chloride are usually used. By incineration of chlorine-containing substances, such as
SOx is generated by incineration of sulfur-containing substances such as oils, and the exhaust gas derived from the incinerator contains a large amount of acidic gas.

Therefore, in general, in the incineration plant, from the viewpoint of preventing air pollution, powdered slaked lime (Ca (OH) ₂ ) showing a strong alkali is introduced into the acidic exhaust gas to neutralize the acidic exhaust gas. Currently, only municipal incinerators nationwide consume hundreds of thousands of tons of Ca (OH) ₂ at present.

On the other hand, when these dusts are incinerated, metal oxides such as silica, aluminum and iron remain as residual combustion components, and a part of them remains as fly ash from the inside of the incinerator together with the exhaust gas in the flue. It is guided and introduced into the dust collector. At that time,
Ca (OH) used to neutralize acidic gas as described above
₂ is mixed with the fly ash that has been introduced, and is collected by the dust collector together.

The fly ash collected by the dust collector contains a large amount of lead (Pb) and cadmium (C) in addition to the above metal oxides.
d), containing harmful heavy metal oxides such as mercury (Hg), and harmful compounds such as chlorides, and also neutralizing Ca (OH) ₂ blown for the purpose of neutralizing acidic exhaust gas. In addition to the products CaCl ₂ , CaSO ₄ , CaCO _3, etc., a large amount of unreacted and strongly alkaline Ca (OH) ₂ is also contained. For this reason, the fly ash collected is highly alkaline.

The fly ash generated here is generally introduced into a kneader and subjected to an intermediate treatment with a heavy metal treating agent typified by a chelating agent and / or cement. According to the elution test stipulated in the 48th Environmental Agency Notification No. 13 test, treatment methods that meet the landfill elution standard are individually selected at each incineration facility.

[0007] At that time, the problem is the added amount of the drug and / or cement used to meet the landfill elution standard. That is, when the chemical and / or cement is used at a high addition rate to the generated fly ash, as a result, a large amount of fly ash treated matter is inevitably landfilled. .

Among the harmful heavy metals contained in the fly ash described above, the substance that is extremely difficult to treat is P.
b compound. This is because the Pb compound is an amphoteric compound which has the property of eluting both in alkaline and acidic conditions. Since fly ash is generally highly alkaline as described above, it is inevitably an environment in which Pb compounds are easily eluted. Therefore, in order to suppress the elution of Pb compounds, a large amount of chemicals and / or cement is required. Is required. In addition, it is inefficient and irrational to perform chemical treatment on the fly ash that has been collected after once neutralizing the acidic gas using Ca (OH) ₂ .

On the other hand, recently, a treating agent has been proposed in which Ca (OH) ₂ which is directly blown into the flow of the acidic exhaust gas and fly ash induced in the flue and a heavy metal stabilizing treating agent are mixed. No. 9-99236 discloses Ca (OH) ₂
A material in which porous aluminum silicate or porous silicon dioxide is mixed with C is disclosed in JP-A-9-99234.
A material obtained by mixing a (OH) ₂ with cement, an inorganic adsorbent, a chelating agent, water glass, etc. is further disclosed in JP-A-2000-
No. 42360 proposes a material obtained by mixing Ca (OH) ₂ with an aluminum compound or a clay mineral.

[0010]

However, in the case of the materials described in JP-A-9-99236 and JP-A-9-99234, the neutralization treatment of the acidic exhaust gas is achieved. , For example, the adsorption component of harmful substances is C
When mixed in a (OH) ₂ , it may not be possible to deal with it depending on the amount of the harmful substance in the fly ash, and it is not possible to reliably fix the heavy metals in the fly ash. Also,
If a large amount of harmful substances contained in fly ash,
An extremely large amount of Ca (OH) ₂ is required, which is uneconomical.

On the other hand, the neutralizing agent for Ca (OH) ₂ is Ca
When mixed in (OH) ₂ , the amount of residual Ca (OH) ₂ is affected depending on the amount of acid gas generated, which causes a difference in the amount of consumption of the neutralizing agent, and is a sufficient amount of harmful substances. It is not always possible to deal with. This is because the acid / alkalinity of fly ash is determined depending on the amount of unreacted Ca (OH) ₂ remaining in the fly ash, and the amount of Pb compound eluted is determined depending on the situation. Therefore, harmful heavy metals may be eluted from the fly ash after the water kneading treatment.

Further, in the case of the material described in Japanese Patent Laid-Open No. 2000-43260, the mixing ratio of the aluminum compound group and the clay mineral is not sufficiently low with respect to Ca (OH) ₂ , and therefore the smoke is There is a drawback in that the amount of mist blowing agent used increases and the total amount of waste that is finally used for landfill disposal increases.

For example, in the example of the publication, when the aluminum compound to be mixed is AlCl ₃ (aluminum chloride) with respect to 100 parts by weight of Ca (OH) ₂ ,
The optimum addition weight part range is described as 40 to 66.6 parts by weight, and Al ₂ (S 0 ₄ ) described in Example 4 is used.
_In the case of an aluminum compound mixed with ₃ (aluminum sulfate), 65.5 parts by weight of the aluminum compound must be mixed with 100 parts by weight of Ca (OH) ₂ , and the flue of the present invention. The amount of aluminum compound required is about 3 to 8 times greater when compared to the insufflation agent.

As is well known, in view of the current situation of land shortage in Japan and the land attraction problem in landfill disposal site construction in many areas, how can the amount of landfill disposal be reduced? It is a big social problem.

Therefore, regarding the insufflation agent, Ca (O
It is strongly demanded that the content of the heavy metal stabilizing treatment agent with respect to H) _{2 be} extremely reduced and the amount of landfill treatment be reduced to address environmental problems.

The object of the present invention is to solve the above-mentioned problems in the conventional treatment agent blown into the flue, to completely carry out the neutralization treatment of exhaust gas, and to use harmful heavy metals in fly ash in a small amount with a chemical agent. It is an object of the present invention to provide a composite type flue blowing agent which can be reliably fixed in an amount and an effective use method thereof.

[0017]

In order to achieve the above object, the present inventor has normally collected dust in the following facts and findings: (1) harmful heavy metal compounds contained in fly ash. In the highly alkaline fly ash, in view of the landfill elution standard, the only problematic compound is the Pb compound. (2) The Pb compound has a pH of 7.5 to 11.
The elution amount of Pb is extremely small in the range of about 5, and the Pb compound can exist stably in such an environmental region.
(3) The powdery highly reactive slaked lime having a specific surface area of 30 m ² / g or more is most suitable for neutralizing the acidic gas,
(4) Fly ash itself exhibits high alkalinity due to the presence of unreacted Ca (OH) _{2 that} has not been subjected to a neutralization reaction with acidic exhaust gas when contacting and coexisting with acidic exhaust gas, ( 5) Based on the facts and findings that harmful heavy metal compounds cannot be eluted when residual Ca (OH) ₂ can be completely neutralized, specific aluminum hydroxide can be added to Ca (OH) ₂ And, it was found that a composite type flue blowing agent in which a specific amount of activated alumina and / or activated alumina coexisted achieves the above-mentioned problems, and has achieved the present invention.

That is, the composite type flue gas-injecting agent of the present invention can form a solid solution with calcium hydroxide which is a highly reactive slaked lime having a specific surface area of 30 m ² / g or more in a temperature range of 110 ° C to 1300 ° C. , aluminum hydroxide having an average particle diameter of 10~45μm and / or activated alumina (gamma-A1 ₂
0 ₃ ) is uniformly mixed, and the mixing ratio of the calcium hydroxide and the aluminum hydroxide and / or activated alumina is 100% by weight of calcium hydroxide and / or aluminum hydroxide and / or activated alumina. Alumina is 3.01 to 11.54 parts by weight in terms of the amount of aluminum element.

More preferably, in the above composite type flue-injection medicine, the mixing ratio of the calcium hydroxide to the aluminum hydroxide and / or activated alumina is 100% by weight of calcium hydroxide. The amount of aluminum and / or activated alumina is 3.85 to 8.65 parts by weight in terms of the amount of elemental aluminum.

The method of using the composite type flue blowing agent of the present invention is as follows: 110 ° C. in the flue from the incinerator to the dust collector.
It is characterized in that the composite flue gas-injecting agent of the present invention is supplied to the above temperature locations to treat fly ash and exhaust gas passing through the temperature locations.

Another method of using the combined flue blowing agent of the present invention is to use the combined flue blowing agent of the present invention at a temperature of 110 ° C. or higher in the flue from the incinerator to the dust collector. It is characterized in that each component of calcium hydroxide and aluminum hydroxide and / or activated alumina is separately supplied so as to have a composition, and fly ash and exhaust gas passing through the temperature location are treated.

Preferably, in the above-described method of using the composite flue blowing agent, the composite flue is further mixed with soot dust by a dust collector and collected, and then uniformly mixed with water by a humidifying and kneading facility. It is characterized by treating the insufflation drug.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The composite type flue blow agent of the present invention comprises calcium hydroxide which is a highly reactive slaked lime having a specific surface area of 30 m ² / g or more, and aluminum hydroxide powder and / or activated alumina. The blending ratio of aluminum hydroxide and / or activated alumina is 3.0 in terms of aluminum based on 100 parts by weight of calcium hydroxide.
1 to 11.54 parts by weight, and the particle size is 10 to
In the range of 45 μm, it is uniformly mixed and dispersed with the calcium hydroxide powder.

In the composite type flue blowing agent of the present invention, C
a (OH)_TwoThe powder is due to acid gas and dust burning
After being blown and supplied to the flow of fly ash generated by
If the ambient temperature is 110 ° C or higher, the acidic gas immediately
Neutralizes with Ca_2,CaSO_Three, CaS
O_FourAnd CaCO_ThreeProduces neutralized salts such as. In addition,
Supplied aluminum hydroxide and / or activated alumina (γ
-Al _TwoO_Three) Is the flying ash and Ca (OH)_Two
Collides with powder etc. and solidifies in the temperature range of 110 ℃ ～ 1300 ℃.
Form a solution.

The solid solution may be, for example, A ₃ S ₂ (3A
1 ₂ 0 ₃ · 2Si0 ₂ ) and CA ₆ (CaO · 6A1 ₂₎
0 ₃ ), CA ₂ (CaO · 2A1 ₂ 0 ₃ ), CA (Ca
O · A1 ₂ 0 ₃ ), C ₁₂ A ₇ (12CaO · 7A1 ₂
0 ₃ ), C ₃ A (3CaO · A1 ₂ 0 ₃ ), C ₂ AS
(2CaO ・ A1 ₂ 0 ₃・ Si0 ₂ ) and further CSH
(Ca-Si hydrate) is presumed to exist.

These solid solutions are Ca (OH) ₂ , aluminum hydroxide and / or activated alumina, and SiO _{2 in} fly ash after the composite flue blowing agent of the present invention is supplied to the flue. It is thought that when each fine particle of each powder collides with each other, it will be formed by fusion at the surface interface of the particles of multiple powders, with the opportunity of adhesion or contact on the surface of the fine particle. .

For example, two particles fused to an array type or the like are collected as they are, and as will be described later, a Henschel type mixer, a pressure molding type twin-screw kneader, a pan type granulator, a vibro mixer, etc. When the fly ash collected is introduced into a simple kneader and advanced kneading with water addition is carried out, the harmful lead compounds are not eluted, and the range is 7.5 to 11.5 p.
It will be controlled in the H area range.

The above pH control cannot be achieved only by forming the above-mentioned array-type fused body, for example. That is, in the slaked lime (Ca (OH) ₂ ) supplied to the flue, in addition to the slaked lime used for neutralizing the acidic gas and the slaked lime used for forming the solid solution, unreacted slaked lime not supplied for the reaction Even if the slaked lime powder particles that are present and form an interfacial fusion body on the powder surface, the slaked lime portion on the side opposite to the aluminum compound powder is likely to be unreacted slaked lime. .

In the present invention, it is important that the agent complexed with Ca (OH) ₂ is aluminum hydroxide and / or activated alumina.
H) ₂ is present in fly ash as well as unreacted particles are present in aluminum hydroxide and / or activated alumina, and is also present in fly ash.

In the alumina compound, activated alumina is first compounded, but when unreacted activated alumina remains in the fly ash, this unreacted activated alumina is promptly mixed when it comes into contact with water in the kneader. Since aluminum hydroxide changes to aluminum hydroxide, here aluminum hydroxide is changed to Ca (O
H) The case where it is used as a complex drug for ₂ will be described.

The unreacted aluminum hydroxide is converted into aluminum hydroxide trihydrate {Al (OH) ₃ (H ₂ O) ₃ } in the kneader in the presence of a large amount of water provided for kneading. Behave. This aluminum hydroxide trihydrate has the characteristic of exhibiting a remarkable pH buffering action. For example, when aluminum hydroxide trihydrate is present in a strongly acidic atmosphere, aluminum hydroxide trihydrate absorbs protons (H ⁺ ) in the system,
_{{Al (OH) 2 (H} 2 O) 4} By changing the ^ten action continue to neutralize the pH in the system to function.

On the contrary, in a strong alkaline atmosphere, protons are released and changed to {Al (OH) ₄ (H ₂ O) ₂ } ^- , which also neutralizes the pH in the system. Works.
That is, the pH of the kneaded material of the fly ash and water is in the pH range in which the harmful lead compound is not eluted, which is the desired value of the present invention, due to both the solid solution formation and the pH buffering action described above.
It is controlled in the range of ~ 11.5.

Ca (O) which produces the same effect as the present invention
In addition to the aluminum hydroxide and activated alumina used in the present invention, an aluminum acid salt such as aluminum chloride, polyaluminum chloride, aluminum nitrate, and aluminum sulfate can be considered as the agent to be combined with H) ₂ .

However, as described above, since it is necessary to suppress the final landfill amount of the fly ash treated product, it is necessary to reduce the amount of additive compounded with Ca (OH) ₂ as much as possible. Aluminum and polyaluminum chloride,
When using an aluminum acid salt such as aluminum nitrate or aluminum sulfate, unlike the aluminum hydroxide and / or activated alumina of the present invention, a large amount must be used, which is not economical and is a landfill amount. Will be huge. Therefore, in order to achieve the above object, aluminum hydroxide and / or activated alumina must be used.

The particle size of the aluminum hydroxide and / or activated alumina should be in the range of 10 to 45 μm. As described above, when the composite agent of the present invention is blown into the exhaust gas in the flue and the suspended dust, the residual unreacted slaked lime and the uniformly mixed aluminum hydroxide and / or activated alumina and the suspended dust. Contact or collision of the powder with the flue or on or near the surface of the dust collector. At that time, powder Ca (OH) ₂ particles and aluminum hydroxide and
/ Or activated alumina forms a solid solution upon collision, but this is not a molecular reaction, but fusion of chemical forms on the particle surface of Ca (OH) ₂ or aluminum hydroxide and / or activated alumina powder. Is.

Due to the formation of such a solid solution, the injected Ca
Residual powder Ca (OH) _{2 in the} total amount of (OH) ₂ decreased, and as a result, elution of Pb compound was suppressed p
Create an H environment. Here, by controlling the particle size of the aluminum hydroxide and / or the activated alumina to a small value of 10 to 45 μm, the solid solution formation can be achieved extremely rationally.

The above particle size range is considered in relation to the powdery highly reactive slaked lime having a specific surface area of 30 m ² / g or more, which is an essential component of the present invention. That is, 30m
It is known that powdery highly reactive slaked lime of ² / g or more is an aggregate of fine particles. In these powdery highly reactive slaked limes of 30 m ² / g or more, submicron-order fine particles form secondary particles, tertiary particles and higher-order aggregated particles, and the particle size of the aggregated particles is about several tens of μm. Is known to be. Therefore, the effect of the present invention can be effectively exhibited only when the particle size of the aluminum hydroxide and / or activated alumina of the present invention is extremely close to the particle size of the highly reactive slaked lime.

Generally, in an incinerator, the flow velocity of exhaust gas passing through the flue near the entrance of the dust collector for blowing Ca (OH) ₂ for neutralizing acid gas is typically in the range of about 10 to 20 meters per second. Is. Fly ash caused by incineration is guided to the dust collector by riding on the flow of exhaust gas at such a speed.
It is known that the particle size of this fly ash shows a distribution of about 10 μm to several hundreds of μm.

Since the Ca (OH) ₂ particles form aggregate particles of about several tens of μm as described above, the particle size is suitable for the fly ash particle size, and the fly ash particles occupying the exhaust gas are It can be dispersed almost uniformly. Ca (O
H) When aluminum hydroxide and / or activated alumina mixed with ₂ is 10 μm or more, it is uniformly dispersed in the fly ash particles without losing against the flow of exhaust gas at this high flow velocity and the collision of suspended fly ash. I can go.

On the contrary, when the particle diameter of the aluminum hydroxide and / or the activated alumina is less than 10 μm, the aluminum hydroxide and / or the activated alumina are extruded from the high-speed exhaust gas flow, and are sufficiently uniformly dispersed in the fly ash. It will not be possible. As a result, it cannot be fused with Ca (OH) ₂ particles, Ca-Al solid solution formation which is the object of the present invention becomes insufficient, and therefore the pH of the fly-ash water-kneaded product is not sufficiently lowered,
This leads to Pb elution.

On the other hand, when the average particle size of aluminum hydroxide and / or activated alumina exceeds 45 μm, the collision frequency, which is the pre-stage of Ca-Al solid solution system formation, cannot be sufficiently obtained, After all, the pH of the fly ash treated with water is not sufficiently lowered, leading to Pb elution.
It is considered that this is because the total surface area of all aluminum hydroxide and / or activated alumina decreased as the particle size of aluminum hydroxide and / or activated alumina increased. Therefore, in order to be able to disperse sufficiently uniformly in the fly ash without losing the high flow velocity, and to obtain a sufficient surface area, the aluminum hydroxide and / or activated alumina of the present invention described above is required. Must be in particle size range.

Next, a method for using the composite type flue blown drug of the present invention will be described. The flue gas-injecting agent of the present invention has a temperature of 110 ° C. or higher, preferably 110 ° C. to 1300 ° C., in the process from the incinerator for incinerating waste to the dust collector.
By supplying to a place having a temperature of, acidic exhaust gas neutralization can be exhibited. At the same time, the aluminum hydroxide and / or activated alumina complexed with the unreacted Ca (OH) ₂ powder, which was not used for neutralizing the acidic exhaust gas, starts forming a solid solution. Then, after collecting the fly ash supplied with the chemical agent of the present invention, it is guided to an advanced kneader such as a Henschel type mixer, a pressure molding type twin-screw kneader, a pan type granulator, and a vibro mixer, where Only by kneading with water, the effect of suppressing the elution of harmful heavy metal compounds in fly ash is exhibited.

Furthermore, the powder Ca (OH) ₂ and the aluminum hydroxide and / or activated alumina having the above-mentioned characteristics are smoked individually so as to form the composition of the composite type flue-injection medicine of the present invention. It can also be supplied along the way.

When the composite type flue gas-injecting agent is supplied to a place where the temperature is lower than 110 ° C., the above-mentioned solid solution formation does not proceed sufficiently, and as a result, the desired p value of the present invention is obtained.
It is not possible to achieve the object of the present invention because it is not controlled within the range of H region (has no elution of harmful lead compounds) from 7.5 to 11.5. Generally, most of the refuse incinerators are already equipped with a slaked lime spray supply device, and the temperature of such a part is usually in the range of 110 to 350 ° C. Therefore, in using the composite type flue gassing agent of the present invention, a special device is not particularly required, and a usual slaked lime supply device can be used.

However, this does not exclude the use of the composite type flue blowing agent of the present invention in a temperature range of 350 ° C. or higher, and it can be effectively used even at a temperature of 350 ° C. or higher. Of course, you can

[0046]

EXAMPLES The present invention will be described with reference to the following examples, comparative examples and test examples. Examples 1 to 21 Comparative Examples 1 to 9 (1) Preparation of composite type flue blowing agents A mixture of the formulations shown in Table 1 was uniformly mixed to prepare composite type flue blowing agents A to Y. did.

[0047]

[Table 1] The particle size of the powder was analyzed using a laser diffraction particle size distribution analyzer SALD-2100 manufactured by Shimadzu Corporation.
The stated particle size is the 50% average particle size. Also, Ca
For the measurement of the specific surface area of (OH) _2, an automatic specific surface area measuring device Gemini 2375 manufactured by Shimadzu Corporation was used, and the measurement was performed by the BET multipoint method using nitrogen gas as an adsorption gas.

(2) Test example of combined flue blowing agent The obtained combined flue blowing agents A to Y shown in Table 1 were used to incinerate facilities 1 to 3 shown in Table 2. HCl at the facility
The concentration, Pb content, Pb elution amount, and pH were measured, and the results are shown in Table 3.

[0049]

[Table 2]

[0050]

[Table 3] Note 1) The average value for a typical three days during the test period. Note 2) The HCl inlet concentration is the value measured before the dust collector and upstream of the injection position of the combined flue agent. Note 3) HCl outlet concentration is the concentration value of HCl concentration at the facility installed in the middle of the stack. Note 4) Pb content is the value measured with the collected fly ash and dry ash. Note 5), 6) These are the values measured based on the Environmental Agency Notification No. 13 test of 1973, after curing the kneaded product with the kneader at the test facility for 1 day. Note 7) Ton of waste means per ton of municipal waste.

For all the examples and comparative examples shown in Table 3, the amounts of Cd, Hg, As, Se and Cr ⁶⁺ eluted were also confirmed, but none were detected.

From Table 3, the following facts are clear. (1) Regarding the combined type flue gas-injecting chemicals A to Y described in Table 1, by supplying a predetermined amount of the chemicals into the flue gas as shown in Table 3, acid flue gas neutralization can be achieved. it can.

(2) When the dust collecting ash treatment is carried out according to the respective chemical supply conditions shown in Table 3, the aluminum hydroxide and / or the activated alumina of the aluminum equivalent weight part of the present invention has a specific surface area of 30 m ² / g or more. When uniformly mixed with highly reactive slaked lime, the pH of the dust-collected ash treated product is controlled to an appropriate range regardless of the amount of blown slaked lime. Elution of heavy metal compounds can be completely suppressed.

(3) The specific surface area of powdered slaked lime mixed with aluminum hydroxide and / or activated alumina is 30 m
If it does not reach ² / g, for example JIS special slaked lime (classification: industrial lime, type: slaked lime, grade: special issue, certified by Japan Institute of Industrial Technology), the aluminum compound as in Comparative Example 9 The target pH control is not achieved even if a predetermined amount of Pb is uniformly mixed, resulting in the elution of the Pb compound.

(4) Further, as in Comparative Examples 5 and 7, even if the aluminum compound to be composited is AlCl ₃ or Al ₂ (SO ₄ ) ₃ which is not restricted by the present invention, its aluminum equivalent compounding. If the parts by weight are within the restriction range of the present invention, the purpose of suppressing elution of harmful heavy metal compounds is met. However, at this time, the supply amount of the composite type flue gas injecting agent becomes considerably large, which deviates from the viewpoint of reducing the amount of landfill disposal that is originally required.

(5) As in Comparative Examples 6 and 8, when the mixing parts by weight in terms of aluminum are blended at the required addition ratio of the present invention or less, a sufficiently large amount of the admixture with respect to Ca (OH) ₂ . However, although the initial purpose was not achieved, that is, the neutralization of the acidic exhaust gas was achieved, the pH of the treated product could not be controlled within an appropriate range, and therefore harmful Pb
Elution of compounds exceeds the standard value for landfill elution.

[0057]

As is clear from the above description, by using the composite type flue blowing agent of the present invention, acid gas neutralization of exhaust gas in an incinerator can be achieved, and at the same time, a slight amount of fly ash can be produced. By adding a heavy metal treatment agent, reliable stabilization of harmful heavy metals can be achieved. In addition, the total amount of waste finally used for landfill disposal, etc. can be extremely reduced, and a combined flue blowing agent and a method of use in consideration of environmental problems can be obtained.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4D002 AA02 AA19 AB01 AC04 BA03                       BA14 BA20 DA05 DA08 DA11                       DA12 DA35 EA03 GA01 GB08                       GB12 HA01                 4D004 AA37 AB03 AC05 CA15 CA34                       CA45 CC03 CC12 DA03 DA06                       DA10 DA20

Claims (5)

[Claims] 1. A calcium hydroxide having a specific surface area of 30 m ² / g or more, and aluminum hydroxide and / or activated alumina having an average particle diameter of 10 to 45 μm capable of forming a solid solution in the temperature range of 110 ° C. to 1300 ° C. (γ-Al
₂ O ₃ ), and the mixing ratio of the calcium hydroxide and the aluminum hydroxide and / or activated alumina is 100 parts by weight of calcium hydroxide and / or aluminum hydroxide and / or Activated alumina is 3.01 to 11.54 parts by weight in terms of the amount of elemental aluminum. 2. The composite type flue blow agent according to claim 1, wherein the mixing ratio of the calcium hydroxide and the aluminum hydroxide and / or activated alumina is 100 parts by weight of calcium hydroxide and water. Aluminum oxide and
A composite flue blowing agent characterized in that / or activated alumina is 3.85 to 8.65 parts by weight in terms of the amount of aluminum element. 3. The composite flue blowing agent according to claim 1 or 2 is supplied to a temperature location of 110 ° C. or higher in the flue from the incinerator to the dust collector, and fly ash passing through the temperature location is supplied. A method of using a composite type flue-blowing agent, characterized by treating exhaust gas. 4. Calcium hydroxide and aluminum hydroxide so as to have the composition of the composite type flue blowing agent according to claim 1 or 2 at a temperature of 110 ° C. or higher in the flue from the incinerator to the dust collector. And / or each component of activated alumina is separately supplied to treat the fly ash and the exhaust gas passing through the temperature location, and a method for using a flue blowing agent. 5. The method of using the composite type flue blowing agent according to claim 3 or 4, further comprising: mixing with soot dust by a dust collector to collect the dust, and then uniformly kneading with water by a humidification kneading facility. A method of using a flue blowing agent characterized by treating a combined flue blowing agent.