JPH1176992A - Treating agent for heavy metal and treatment by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To treat heavy metals included in a combustion waste gas without producing harmful gas by using a heavy metal treating agent comprising a specified carbonate compd. and/or a specified hydrogen carbonate compd. of specified formula and an ion exchanger for the treatment of heavy metals at high temp. SOLUTION: As the heavy metal treating agent, a carbonate compd. expressed by the general formula of Mn CO3 is used. In the formula, M is an alkali metal, an alkaline earth metal, ammonium or iron, and (n) is 2 when M is the alkali metal to ammonium, and (n) is 1 when M is the alkaline earth metal or iron. Or, a hydrogen carbonate compd. expressed by the general formula of M(HCO3 )m (wherein M is an alkali metal, an alkaline earth metal, ammonium or iron, and (m) is 1 when M is the alkali metal or ammonium and (n) is 2 when M is the alkaline earth metal or iron) is used for the heavy metal treating agent. Thereby, harmful gas such as hydrogen chloride which is produced in a treating process of a solid waste containing heavy metals can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to solid waste containing heavy metals, for example, incineration ash and fly ash discharged from garbage incineration plants, slag discharged from mines and metal smelters, and heavy metal contaminated. The present invention relates to a method for more easily fixing harmful heavy metals such as lead, mercury, chromium, cadmium, zinc, and copper contained in soil and sludge generated after wastewater treatment, and making it possible to elute them.

[0002] In particular, the present invention provides a method suitable for treating incinerated ash and fly ash from incineration plants such as municipal waste and industrial waste, or for treating heavy metals contained in combustion exhaust gas from incineration plants.

[0003]

2. Description of the Related Art In recent years, a method using an amine derivative has been proposed as a method for collecting and immobilizing heavy metals in wastewater or solid waste. In particular, regarding the treatment method using dithiocarbamic acid and its salt among the amine derivatives,
Numerous proposals have been made. In the field of wastewater treatment, Japanese Patent Publication No. 56-39358 and Japanese Patent Publication No. 4-327
No. 17 publication.

[0004] The technology relating to dithiocarbamates cultivated in the field of wastewater treatment has been applied to the treatment of solid waste containing heavy metals. Specific examples of heavy metal-containing solid waste include incinerated ash and fly ash discharged from incineration plants for municipal waste and industrial waste. Fly ash is collected by an electric dust collector (EP) or a bag filter (BF) and then landfilled or dumped into the sea. However, these fly ash contains a large amount of harmful heavy metals, and is generated by rainwater from landfills. Elution of lead, mercury, etc. may cause environmental pollution. For this reason, fly ash is designated as a specially controlled waste, and is subjected to any of the following methods: "solidification method for cement", "extraction method with acid or other solvent", "melt fixation method" or "chemical addition method". , Are obliged to be disposed of.

[0005] Among them, the drug addition method is generally simpler in equipment and handling than other methods, and thus various proposals have been made. For example, a method in which an inorganic sulfide is used in combination with a dithiocarbamate using a polyamine such as polyethyleneimine as a raw material is disclosed in JP-A-5-50055 and the like, and a dithiocarbamate of a low molecular weight polyamine and a dithiocarbamate of a high molecular weight polyamine are disclosed. Is disclosed in JP-A-3-231921. Regarding the use of a dithiocarbamate of a low molecular weight polyamine alone, a method using dithiocarbamate using diethylenetriamine as a raw material is disclosed in JP-A-6-79254. However, in these methods, the temperature inside the kneading system may be increased due to the heat generated during the kneading of the humidified water and the chemical with the fly ash, which may induce the decomposition of dithiocarbamate. In some cases, the generation of harmful gases such as carbon and the ability to treat heavy metals of chemicals may be reduced.

Further, JP-A-5-92122 and JP-A-5-208117 disclose a dithiocarbamic acid-based compound, a thiol-based compound, and a mercaptan-based compound in a flue gas at a high temperature of 200 to 300 ° C. in an incineration plant. A method of spraying a compound or the like to remove heavy metals, particularly mercury, has been proposed. However, according to the findings of the present inventors, the decomposition temperature of dithiocarbamate is 190 ° C. even in nitrogen, and when the present compound is sprayed into a flue under highly oxidizing conditions, its decomposition temperature The generation of hydrogen sulfide gas and carbon disulfide gas, which are substances, is remarkable, harmful, and equipment corrosion is severe.

Further, organic chemicals represented by dithiocarbamic acid fly ash treating agents are said to have a high ability to immobilize heavy metals, but there is no matrix other than the fly ash itself, which holds the produced organic chelate complex. The question remains whether long-term storage stability can be fully expected.

Further, regarding fly ash treatment, EP or B
Exhaust gas and dioxin countermeasures are required in addition to soot and dust measures by collecting F, etc., and the properties of the fly ash obtained greatly differ depending on these measures. It is known that the amount of heavy metal eluted in highly alkaline fly ash increases, especially the amount of lead eluted in an alkaline region. In order to immobilize such heavy metals in fly ash, the amount of the conventional chemicals to be used is greatly increased, or a pH adjuster such as phosphoric acid, a sulfate band, ferric chloride, or another cement or the like is used. There has been a problem that a combined use method with a medicine must be used, the cost of a treatment chemical increases, or the treatment method becomes complicated. For example, Japanese Patent Publication No. Hei 4-61710, Japanese Unexamined Patent Publication No. Hei 2-1441
No. 88 and Japanese Patent Application Laid-Open No. Hei 7-155725 propose fly ash treatment using a phosphate compound. However, in these methods, it is necessary to add calcium hydroxide as a pH adjuster or a calcium source. The pH range of possible fly ash is limited, the ability to immobilize heavy metals is insufficient, and when phosphoric acid itself, which is an acidic substance, is used, there is a problem in that corrosion of the apparatus is caused. Also, a method of fly ash treatment using a combined system of a phosphate compound and a silicate compound is disclosed in Japanese Patent Laid-Open No. 7-398.
48, proposed in Japanese Patent Application Laid-Open No. 7-185500. Similarly, these methods also have problems in that the amount added to fly ash is large, the pH range is limited, and the ability to fix heavy metals is inferior.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art. That is, even if a heavy metal treatment is carried out under a high temperature condition, generation of harmful gas due to decomposition and equipment corrosion do not occur. Another object of the present invention is to provide a heavy metal treating agent having a high heavy metal treating ability and a treating method.
Further, it is an object of the present invention to provide an efficient treatment method and a treatment agent capable of treating heavy metals in all pH ranges, and a treatment method and a treatment agent capable of expecting that the treated solid waste is stable for a long period of time. This is also an object of the present invention.

[0010]

The present inventors have SUMMARY OF THE INVENTION As a result of extensive studies to solve the above problems, in general surprisingly formula formula M _n CO ₃ (wherein, M is an alkali metal, alkaline An earth metal, ammonium or iron, and n is 2 when M is an alkali metal or ammonium and 1 when M is an alkaline earth metal or iron) and / or a general formula M (HCO ₃ ) _m Wherein M is an alkali metal, an alkaline earth metal, ammonium or iron, and m is 1 when M is an alkali metal or ammonium and 2 when M is an alkaline earth metal or iron. Found that the heavy metal treating agent consisting of and an ion exchanger can perform heavy metal treatment with high efficiency without generating harmful gas and decomposition of equipment even when performing heavy metal treatment under high temperature conditions. This has led to the completion of the present invention.

That is, the present invention relates to a treating agent comprising the above-mentioned carbonate compound and / or hydrogen carbonate compound and an ion exchanger, and to a method for treating heavy metal-containing solid waste using the treating agent. .

In particular, the present invention relates to a heavy metal treating agent using an organic chelating agent, an aluminosilicate, a phosphoric acid compound or a silicate compound as an ion exchanger and a treating method using the same.

[0013] The heavy metal-containing solid waste to be used in the present invention is not particularly limited.
Incineration ash (furnace ash) discharged from incineration facilities such as municipal waste and industrial waste, ash dust collected by electric dust collectors, bag filters, multicyclones, etc., so-called fly ash, mines and metal smelters It can be applied to discharged slag, soil contaminated with heavy metals, sludge generated after wastewater treatment, and the like.

In particular, the agent is applicable to the treatment of heavy metal-containing solid waste at high temperatures in the range of 150 ° C. to 400 ° C. For example, it is possible to fix heavy metals by spraying them into the flue of high-temperature flue gas from an incineration plant, and without spraying a dehydrochlorinating agent such as slaked lime that is usually used for dry treatment of flue gas. With only the agent, dehydrochlorination in exhaust gas and heavy metal treatment can be performed.

The general formula M _n CO ₃ used in the heavy metal treating agent of the present invention, wherein M is an alkali metal, alkaline earth metal, ammonium or iron, and n is 2 when M is an alkali metal or ammonium. Yes, and in the case of an alkaline earth metal or iron, it is 1).

Alkali metal carbonate such as Li ₂ CO ₃ , Na ₂ CO ₃ and K ₂ CO ₃ , alkaline earth metal carbonate such as MgCO ₃ and CaCO ₃ , (NH ₄ ) ₂ CO ₃ , FeCO ₃ ,
And hydrates thereof, and these can be used alone or as a mixture of two or more.

The general formula M (HCO ₃ ) _m used in the heavy metal treating agent of the present invention, wherein M is an alkali metal, an alkaline earth metal, ammonium or iron, and m is a case where M is an alkali metal or ammonium 1 and in the case of an alkaline earth metal or iron, 2)
The following can be mentioned.

Alkali metal salts of hydrogen carbonate such as LiHCO ₃ , NaHCO ₃ , KHCO ₃ , Mg (HCO ₃ ) ₂ , Ca
(HCO ₃ ) _{2 and} other alkaline earth metal salts of hydrogen carbonate, NH
₄ HCO ₃ , Fe (HCO ₃ ) ₂ , and hydrates thereof can be used, and these can be used alone or as a mixture of two or more.

Further, these carbonate compounds and bicarbonate compounds may be used in combination, and Na ₂ CO ₃ .NaH
Sesquicarbonates such as CO ₃ , MgCO ₃ · KHCO ₃ and hydrates thereof are also included in the scope of the present invention.

Further, by using such a carbonate compound and / or a hydrogen carbonate compound, an effect of removing harmful gases such as hydrogen chloride which may be generated when treating heavy metal-containing solid waste is expected. it can.

The ion exchanger used in the heavy metal treating agent of the present invention includes an organic chelate compound, a crystalline or amorphous aluminosilicate, a phosphate compound, a silicate compound and the like.

Among these, examples of the organic chelating agent include S, S-coordination compound, S, 0-coordination compound, S, N
-Coordination compounds, and representative examples thereof include dithiocarbamic acid compounds and mercaptocarboxylic acid compounds.

As the dithiocarbamic acid compound, a dithiocarbamic acid salt derived from an aliphatic or aromatic amine compound can be used.

The dithiocarbamic acid or a salt thereof that can be used in the present invention can be usually produced by reacting carbon disulfide with an amine compound in the presence of an alkali. The amine compound used in this case is as follows. Compounds can be used.

Specifically, ethylamine, n-propylamine, i-propylamine, n-butylamine, i-
Butylamine, sec-butylamine, amylamine,
Primary amines such as 2-ethylhexylamine, cyclohexylamine, benzylamine and xylenediamine, diethylamine, di-n-propylamine, di-i-propylamine, di-n-butylamine, di-i-butylamine, di- secondary amines such as sec-butylamine, diamylamine, di-2-ethylhexylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, heptaethyleneoctamine, triethylenediamine, etc. Polyethylene polyamines, piperidine, pyrrolidine, piperazine, N
And cyclic amines such as -aminoethylpiperazine.

In these amine compounds, amine 1
The number of dithiocarbamic acid groups or salt groups in the molecule can be any number between one or more and the total number of primary and secondary nitrogen atoms in the molecule, depending on the application.

Further, among these amine compounds, a dithiocarbamic acid group or a salt thereof synthesized from a polyethylene polyamine having 4 or more nitrogen atoms or a cyclic polyamine having 2 or more nitrogen atoms has an ability to capture heavy metals contained in fly ash. High and preferred. In particular, a piperazine derivative having only a secondary amino has a very high ability to capture heavy metals contained in fly ash, and is suitable.

As the dithiocarbamate used in the present invention, the above-mentioned alkali metal, alkaline earth metal or ammonium salts of dithiocarbamic acid can be used. Of these, lithium, sodium, potassium, magnesium, calcium, barium, and ammonium salts are preferred.

The mercaptocarboxylic acid compound is represented by the general formula (1)

[0030]

Embedded image

(Wherein R is one selected from the group consisting of hydrogen, a hydrocarbon group, an alkali metal, an alkaline earth metal and ammonium, and R ¹ and R ² are hydrogen, a hydrocarbon group, an amino group and One kind independently selected from the group consisting of an alkoxy group, wherein the (CR ¹ R ² ) _p portion is linear, branched or cyclic, and A is hydrogen, an alkali metal,
One selected from the group consisting of alkaline earth metals and ammonium, and n is an integer of 1 to 20).

Examples of such compounds include thioglycolic acid, sodium thioglycolate, thioglycol-
Potassium luteate, magnesium thioglycolate, calcium thioglycolate, ammonium thioglycolate, methyl thioglycolate, ethyl thioglycolate, butyl thioglycolate, octyl thioglucolate, thioglucolate 2-ethylhexyl, methoxybutyl thioglycolate, trimethylpropane tris (thioglycolate), 2-mercaptopropionic acid,
Sodium mercaptopropionate, potassium 2-mercaptopropionate, magnesium 2-mercaptopropionate, calcium 2-mercaptopropionate, 2
-Ammonium mercaptopropionate, methyl 2-mercaptopropionate, ethyl 2-mercaptopropionate, butyl 2-mercaptopropionate, 2-ethylhexyl 2-mercaptopropionate, methoxybutyl 2-mercaptopropionate, trimethylpropanetris (2- Mercaptopropionate) 3-mercaptopropionic acid, sodium 3-mercaptopropionate,
Potassium 3-mercaptopropionate, magnesium 3-mercaptopropionate, calcium 3-mercaptopropionate, ammonium 3-mercaptopropionate, methyl 3-mercaptopropionate, ethyl 3-mercaptopropionate, butyl 3-mercaptopropionate, 3 -2-ethylhexyl mercaptopropionate, methoxybutyl 3-mercaptopropionate, trimethylpropanetris (3-mercaptopropione-
G) L-cysteine, L-cysteine hydrochloride monohydrate,
L-cysteine methyl ester hydrochloride, L-cysteine ethyl ester hydrochloride, D-cysteine, D-cysteine hydrochloride monohydrate, D-cysteine methyl ester hydrochloride, D-cysteine ethyl ester hydrochloride, and D-forms thereof , L-form D, L-form mixture, 2-carboxymercaptohexane, 2-mercaptonicotinic acid, and hydrates thereof.

Compounds other than these dithiocarbamic acid compounds and mercaptocarboxylic acid compounds include mercaptopyridine, mercaptothiazoline, mercaptobenzothiazole, trimercaptotriazine, and Na, K, Mg, Ca salts thereof, and the like. These hydrates are mentioned.

These organic chelating agents may be used alone or
It can be used as a mixture of more than one species.

The aluminosilicate used in the present invention - For tracing the general _{formula, Q 2 / q O · Al} 2 O 3 · ySiO 2 · zH
₂ O (where q is the valency of the cation Q, y is a real number of 2 or more, z is a real number of 0 or more, and Q is a cation;
Organic nonmetal cations, organic metal cations, inorganic nonmetal cations, and inorganic metal cations).

Although the crystal structure is not particularly limited, ferrierite, phillipsite, sodalite, cancrinite, aeolinite, offretite, clinoptilolite, gmelinite, chabazite, faujasite, mordenite, A-type zeolite , X-type zeolite, Y-type zeolite and L-type zeolite. These can be used alone or as a mixture of two or more.

[0037] Further, those obtained by adding a binder to these aluminosilicates and forming them into particles, or those obtained by ion exchange with a solution of a desired salt such as an alkali metal salt or an alkaline earth metal salt can also be used. A known method may be used.

Of these aluminosilicates, A-type zeolites can be used in consideration of their ion exchangeability and heat resistance.
It is preferable to use X-type zeolites and Y-type zeolites. From the viewpoint of economy, A-type zeolites, especially 4A
Type zeolites are practical.

The phosphoric acid compound used in the present invention includes:
Lithium salts, sodium salts, and potassium salts of orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, and polyphosphoric acid are included. Specifically, sodium monophosphate, sodium phosphate dibasic, sodium tertiary phosphate, sodium hypophosphite, sodium pyrophosphate, sodium metaphosphate, sodium hexametaphosphate, sodium tripolyphosphate, potassium monophosphate, potassium diphosphate And potassium tertiary phosphate, potassium hypophosphite, potassium pyrophosphate, potassium metaphosphate, potassium hexametaphosphate, potassium tripolyphosphate and the like. These can be used alone or as a mixture of two or more.

The silicate compound used in the present invention includes:
Ortho-silicic acid, di-silicic acid, meta-silicic acid, pyrosilicic acid, water glass and their lithium salts, sodium salts, potassium salts,
Furthermore, these hydrates etc. are mentioned. These can be used alone or as a mixture of two or more.

The ion exchanger used in the heavy metal treating agent of the present invention may be any of organic chelate compounds, aluminosilicates, phosphate compounds, silicate compounds and the like as described above. When used alone as an exchanger, an organic chelate compound, an aluminosilicate
G is more practical because it is effective even in small quantities.

Further, as the ion exchanger used in the heavy metal treating agent of the present invention, a combination of two or more of the above-mentioned organic chelate compounds, aluminosilicates, phosphate compounds and silicate compounds may be used. Can also.
For example, by combining an organic chelate compound and an aluminosilicate, it is possible to more effectively perform a trapping treatment of heavy metals in heavy metal-containing solid waste. One example of the effect is that the heavy metal ion species that can be effectively trapped based on the characteristics of the ion exchanger used can be made wider than in the case of single use, so that the heavy metal-containing solid waste to be treated is used. Even if the types of heavy metals and their concentrations vary, they can be comprehensively captured.

The quantitative ratio of the above-mentioned carbonate compound or hydrogen carbonate compound to the ion exchanger is not particularly limited, and can be arbitrarily changed depending on the heavy metal content and form of the heavy metal-containing solid waste to be treated. it can.

As the form of the ion exchanger in the present invention, any form can be used. That is, any of solid, powder, slurry, and solution forms can be used.

Further, in the present invention, NaOH, Mg
(OH) ₂ , Ca (OH) ₂ , FeCl ₂ , FeCl ₃ , A
pH adjusters such as l (OH) ₃ and Al ₂ (SO ₄ ) ₃ can also be used in combination.

The amount of the agent of the present invention used for treating heavy metal-containing solid waste can be varied depending on the heavy metal content and form in the heavy metal-containing solid waste to be treated.

The method of treating heavy metal-containing solid waste with the present heavy metal treating agent includes a method of kneading, a method of spraying, a slurry of the treating agent or a solution of the present treating agent in a temperature range of -20 ° C to 350 ° C. Any method such as a method of immersion in water can be adopted.

The heavy metal in the solid waste containing heavy metal to be treated by the method of the present invention can be exemplified by lead, mercury, chromium, cadmium, zinc, copper, nickel, arsenic, selenium and the like. In particular, lead, mercury, chromium, cadmium, nickel,
Zinc and copper are preferred because of their high processing ability.

[0049]

Next, the present invention will be described in more detail by way of examples. However, the present invention is not limited by the following examples.

Example 1 Neutral incineration fly ash (having a composition of Ca = 10.0) discharged from a stoker incinerator employing wet treatment, which is a solid waste containing heavy metals, in an autoclave. %, Na = 5.5%,
K = 5.4%, Mg = 2.1%, Al = 7.0%, Fe
= 1.8%, Pb = 0.84%, Zn = 3.4%, Cr
= 0.043%, Cd = 0.032%, Cu = 0.25
% Of EP ash), 5.0% by weight of sodium bicarbonate, 2.5% by weight of calcium mercaptoacetate and water 2
After adding 2.5% by weight and kneading at 150 ° C. for 1 hour,
The Environment Agency notification No. 13 dissolution test was performed. Table 1 shows the dissolution test results.

[0051]

[Table 1]

Example 2 In Example 1, 2.5 parts of calcium mercaptoacetate was added.
In the same manner as in Example 1, except that 2.5% by weight of sodium dithiocarbamate of tetraethylenepentamine was used instead of the weight%, the heat treatment and the notification from the Environment Agency No. 13 were carried out.
No. dissolution test was performed. Table 1 shows the dissolution test results.

Example 3 In Example 1, 2.5 parts of calcium mercaptoacetate was added.
In the same manner as in Example 1, except that 5.0% by weight of 4A type zeolite (manufactured by Toso Corp., trade name: Toyo Builder) was used instead of 1% by weight, the heat treatment and the notification of the Environment Agency No. 1 were carried out.
A No. 3 dissolution test was performed. Table 1 shows the dissolution test results.

Comparative Example 1 In Example 1, only 30% by weight of water was added to fly ash without adding sodium hydrogencarbonate and calcium mercaptoacetate, and the mixture was kneaded at room temperature. went. Table 1 shows the dissolution test results.

Comparative Example 2 In an autoclave, 2.5% by weight of sodium dithiocarbamate of tetraethylenepentamine and 27.5% by weight of water were added to the fly ash used in Example 1, and 150% by weight was added. ° C
After kneading for 1 hour, the dissolution test of No. 13 notified by the Environment Agency was conducted. The results of the dissolution test are shown in Table 1. The dissolution amounts of Pb and Cd are at or above the regulated value, which means that sodium dithiocarbamate alone has insufficient heat resistance.

Reference Example In Comparative Example 2, the kneading treatment was performed in the same manner as in Comparative Example 2 except that the kneading treatment at 150 ° C. for 1 hour was performed at room temperature for 1 hour. went. Table 1 shows the dissolution test results. Since the mixture was kneaded at room temperature, the Pb elution value was below the regulation value.

Example 4 Neutral incineration fly ash (composition: Ca = 10.0) discharged from a stoker incinerator employing wet treatment, which is a solid waste containing heavy metals, in an autoclave %, Na = 5.5%,
K = 5.4%, Mg = 2.1%, Al = 7.0%, Fe
= 1.8%, Pb = 0.84%, Zn = 3.4%, Cr
= 0.043%, Cd = 0.032%, Cu = 0.25
% Of EP ash).
0% by weight and 1 of sodium carbonate (soda ash; light ash)
0.0% by weight, 4A type zeolite (manufactured by Toso Corporation,
After adding 20.0% by weight (trade name: Toyovirda) and 10.0% by weight of water and kneading at 200 ° C. for 1 hour, a dissolution test of No. 13 notified by the Environment Agency was carried out. Table 1 shows the dissolution test results.

Example 5 In Example 4, sodium bicarbonate was not added, and the amount of sodium carbonate (soda ash; light ash) was changed to 20.
A heat kneading treatment and a dissolution test of No. 13 notified by the Environment Agency were performed in the same manner as in Example 4 except that the content was 0% by weight. Table 1 shows the dissolution test results.

Comparative Example 3 The procedure of Example 4 was repeated except that sodium bicarbonate and 4A zeolite were not added, and the amount of sodium carbonate (soda ash; light ash) was changed to 20.0% by weight. In the same manner as in Example 4, a heat kneading treatment and a dissolution test of No. 13 notified by the Environment Agency were performed. Table 1 shows the dissolution test results.

Example 6 Neutral incineration fly ash (having a composition of Ca = 10.0) discharged from a stoker incinerator employing wet treatment, which is a solid waste containing heavy metals, in an autoclave. %, Na = 5.5%,
K = 5.4%, Mg = 2.1%, Al = 7.0%, Fe
= 1.8%, Pb = 0.84%, Zn = 3.4%, Cr
= 0.043%, Cd = 0.032%, Cu = 0.25
% Of EP ash).
0% by weight, 20.0% by weight of 4A-type zeolite (Toyobuilder, manufactured by Tosoh Corporation) and 10.0% by weight of water were added and kneaded at 200 ° C. for 1 hour.
A No. 3 dissolution test was performed. Table 1 shows the dissolution test results.

Example 7 The procedure of Example 6 was repeated, except that 20.0% by weight of sodium hydrogencarbonate was replaced by 20.0% by weight of potassium hydrogencarbonate. The Environment Agency notification No. 13 dissolution test was performed. Table 1 shows the dissolution test results.
Shown in

Example 8 The procedure of Example 6 was repeated, except that 20.0% by weight of ammonium hydrogencarbonate was used instead of 20.0% by weight of sodium hydrogencarbonate. The Environment Agency notification No. 13 dissolution test was performed. Table 1 shows the dissolution test results.

Example 9 The same procedure as in Example 6 was carried out except that 20.0% by weight of calcium hydrogen carbonate was used instead of 20.0% by weight of sodium hydrogencarbonate. The Office Notification No. 13 dissolution test was performed. Table 1 shows the dissolution test results.

Example 10 The procedure of Example 6 was repeated, except that 20.0% by weight of X-type zeolite was used instead of 20.0% by weight of 4A-type zeolite. The Office Notification No. 13 dissolution test was performed. Table 1 shows the dissolution test results.

Example 11 The procedure of Example 6 was repeated, except that 20.0% by weight of Y-type zeolite was used instead of 20.0% by weight of 4A-type zeolite. The Office Notification No. 13 dissolution test was performed. Table 1 shows the dissolution test results.

Example 12 The procedure of Example 6 was repeated, except that 20.0% by weight of mordenite was used instead of 20.0% by weight of 4A type zeolite. A thirteenth dissolution test was performed. Table 1 shows the dissolution test results.

Example 13 In the autoclave, molten fly ash α (composition of Ca =
4.1%, Na = 12.0%, K = 12.0%, Mg =
0.38%, Al = 1.3%, Fe = 1.3%, Pb =
3.6%, Zn = 8.7%, Cr = 0.019%, Cd
= 0.059%, Cu = 0.53% BF ash), 20.0% by weight of sodium hydrogencarbonate and 4A type zeolite (Toyobuilder, trade name, manufactured by Tosoh Corporation) 20.0%
After adding 20.0% by weight of water and water and kneading at 200 ° C. for 1 hour, a dissolution test of No. 13 notified by the Environment Agency was performed. Table 2 shows the dissolution test results.

[0068]

[Table 2]

Example 14 In Example 13, 20.0% by weight of 4A type zeolite
Instead of using 20.0% by weight of purified phosphoric acid (75 wt% aqueous solution), a heat kneading treatment and a dissolution test of No. 13 notified by the Environment Agency were performed in the same manner as in Example 13. Table 2 shows the dissolution test results.

Example 15 In Example 13, 20.0% by weight of type 4A zeolite was used.
In place of 20.0% by weight of sodium silicate, a heat kneading treatment and a dissolution test of No. 13 notified by the Environment Agency were conducted in the same manner as in Example 13. Table 2 shows the dissolution test results.

Comparative Example 4 In Example 13, sodium bicarbonate and 4A type zeolite were not added, but only 20.0% by weight of water was added to fly ash, and kneaded at room temperature. No. dissolution test was performed. Table 2 shows the dissolution test results.

Comparative Example 5 A heat kneading treatment and a dissolution test of No. 13 notified by the Environment Agency were conducted in the same manner as in Example 13 except that no zeolite 4A was added. Table 2 shows the dissolution test results.

Comparative Example 6 A heat kneading treatment and a dissolution test of No. 13 notified by the Environment Agency were conducted in the same manner as in Example 13 except that sodium hydrogen carbonate was not added. Table 2 shows the dissolution test results.

Comparative Example 7 In Example 13, sodium bicarbonate was not added.
Heat kneading treatment and dissolution test of the Environment Agency Notification No. 13 in the same manner as in Example 13 except that 20.0% by weight of purified phosphoric acid (75% by weight aqueous solution) was used instead of 20.0% by weight of 4A type zeolite. Was done. Table 2 shows the dissolution test results.

Comparative Example 8 The procedure of Example 13 was repeated, except that sodium bicarbonate was not added and sodium silicate (20.0% by weight) was used instead of 4A type zeolite (20.0% by weight). Similarly, a heat kneading treatment and an elution test No. 13 notified by the Environment Agency were performed. Table 2 shows the dissolution test results.

Example 16 In the autoclave, molten fly ash β (composition: Ca =
1.4%, Na = 13.9%, K = 11.2%, Mg =
0.19%, Al = 0.67%, Fe = 1.4%, Pb
= 4.8%, Zn = 7.8%, Cr = 0.010%, C
20% by weight of sodium bicarbonate and 4A zeolite (Toyobuilder, trade name, manufactured by Toso Corporation) based on BF ash with d = 0.034% and Cu = 0.63%.
After adding 0% by weight and 20.0% by weight of water and kneading at 200 ° C. for 1 hour, a dissolution test No. 13 notified by the Environment Agency was performed. Table 3 shows the dissolution test results.

[0077]

[Table 3]

Example 17 The procedure of Example 16 was repeated, except that 5.0% by weight of sodium diethyldithiocarbamate was used in addition to 20.0% by weight of zeolite 4A as an ion exchanger. The kneading treatment and the dissolution test of the Environment Agency No. 13 were conducted. Table 3 shows the dissolution test results.

Comparative Example 9 In Example 16, only 20.0% by weight of water was added to fly ash without adding sodium bicarbonate and 4A zeolite, and the mixture was kneaded at room temperature. No. dissolution test was performed. Table 3 shows the dissolution test results.

Comparative Example 10 A heat kneading treatment and a dissolution test of No. 13 notified by the Environment Agency were conducted in the same manner as in Example 16 except that no zeolite 4A was added. Table 3 shows the dissolution test results.

Comparative Example 11 A heat kneading treatment and a dissolution test of No. 13 notified by the Environment Agency were conducted in the same manner as in Example 16 except that sodium hydrogen carbonate was not added. Table 3 shows the dissolution test results.

COMPARATIVE EXAMPLE 12 The procedure of Example 16 was repeated, except that 20.0% by weight of calcium hydroxide was used instead of 20.0% by weight of sodium hydrogencarbonate. The Office Notification No. 13 dissolution test was performed. Table 3 shows the dissolution test results.

[0083]

The first effect of the present invention is as follows.
It is that heavy metals can be treated and rendered harmless even under a high temperature condition of 0 ° C. By using this treating agent, it becomes possible to treat heavy metals in combustion exhaust gas from an incineration plant in a flue.

The second effect of the present invention is that it has a high ability to immobilize heavy metals and can be applied to solid waste containing heavy metals in all pH ranges. The effect is economical with the addition of a small amount, and the use of other auxiliaries can be carried out by a safe and simple treatment method, so that it is industrially very useful.

The third effect of the present invention is that since it is a strong treating agent under high temperature and acidic conditions, long-term stability of the treated solid waste can be expected.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C09K 17/02 B01D 53/34 136Z 17/08 B09B 3/00 ZAB

Claims (6)

[Claims] A compound of the general formula M _n CO _{3 wherein} M is an alkali metal, an alkaline earth metal, ammonium or iron;
Is 2 when M is an alkali metal or ammonium,
A carbonate compound of the general formula M (HCO ₃ ) _m , wherein M is an alkali metal, an alkaline earth metal, ammonium or iron;
m is 1 when M is an alkali metal or ammonium, and 2 when M is an alkaline earth metal or iron). A heavy metal treating agent comprising a hydrogen carbonate compound and an ion exchanger. 2. The heavy metal treating agent according to claim 1, wherein the ion exchanger is an organic chelating agent, an aluminosilicate, a phosphate compound or a silicate compound. 3. The heavy metal treating agent according to claim 1, wherein the ion exchanger is at least two members selected from the group consisting of an organic chelating agent, an aluminosilicate, a phosphoric acid compound and a silicate compound. 4. A treatment method comprising adding the heavy metal treating agent according to claim 1 to a heavy waste containing solids. 5. The method according to claim 4, wherein the solid waste containing heavy metals is incinerated ash or fly ash discharged from an incineration plant. 6. The method according to claim 4, wherein the heavy metal treating agent is sprayed onto a flue of combustion exhaust gas from an incineration plant, and collected by a dust collector to remove both hydrogen chloride and heavy metals. 5. The processing method according to 5.