JP2003336035A - Heavy metal fixing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel heavy metal fixing agent which allows effective waste processing, good working environment, easy handling and transportation, and processing cost reduction in spite of the heavy metal being fully fixed. <P>SOLUTION: The heavy metal fixing agent is a powder composed mainly of a dithiocarbamate. A water absorbing material such as kenaf or a water absorbing polymer and/or one or more inorganic materials selected from among a silicate, phosphate, carbonate, sulfate, and hydroxide are optionally used with the heavy metal fixing agent. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heavy metal immobilizing agent.

[0002]

2. Description of the Related Art At present, incinerator ash generated from refuse incinerators, thermal power plants, etc., or heavy metals contained in industrial waste, waste water, contaminated soil, exhaust gas, etc. are detoxified before disposal. Is obligatory. As a heavy metal fixing agent therefor, organic chelating agents have been mainly used conventionally. The organic chelating agent is one that fixes a heavy metal by coordinating with the heavy metal to form a water-insoluble chelate compound.

As a conventional technique relating to an organic chelating agent, for example, in Japanese Unexamined Patent Publication No. 8-332475, a heavy metal fixing agent comprising an aqueous solution of potassium dithiocarbamic acid salt, and the heavy metal fixing agent are added and kneaded to heavy metal-containing ash. Therefore, a method for making the material harmless is disclosed. Further, JP-A-64-90083 is characterized in that an aqueous solution of a metal scavenger having a dithiocarboxy group and / or a salt thereof as a substituent is added to a solid waste containing a heavy metal. A method for immobilizing heavy metals is disclosed.

As described above, all the conventional organic chelating agents as heavy metal fixing agents have been used in a liquid state. The liquid organic chelating agent has an advantage that equipment for kneading with incinerated ash or the like can be relatively inexpensive, but has the following problems. That is, (1) an offensive odor (amine odor) is generated due to the influence of impurities contained in the organic chelating agent, which is not preferable from the viewpoint of working environment. In addition, (2) the organic chelating agent is highly alkaline (pH value is 1
Therefore, care must be taken not to scatter the organic chelating agent during the work. Further, (3) since the organic chelating agent is highly alkaline (pH value is 10 to 14),
Ensuring safety in transportation is important. further,
(4) When the organic chelating agent and the waste are kneaded, if the waste is incinerated ash or the like, the organic chelating agent and the waste react with each other to cause a harmful gas such as carbon disulfide, hydrogen sulfide, or ammonia. Therefore, there is a problem that it is not preferable from the viewpoint of the work environment.

Further, the conventional liquid organic chelating agent has a drawback that the cost is high because a very large amount of liquid is required to almost completely immobilize the heavy metal contained in the waste. .

[0006]

SUMMARY OF THE INVENTION In view of the above conventional circumstances, the present invention is capable of efficiently performing a waste disposal operation, can maintain a good working environment, and is excellent in handleability. It is an object of the present invention to provide a novel heavy metal immobilizing agent that can be easily transported. Further, the present invention is
It is an object of the present invention to provide a novel heavy metal immobilizing agent which is capable of sufficiently immobilizing heavy metals while keeping the treatment cost low.

[0007]

In order to solve the above-mentioned problems, the heavy metal fixing agent of the present invention is characterized in that it is composed of powdery dithiocarbamate.

According to the above means, a powdery dithiocarbamate is provided as a heavy metal fixing agent for kneading with waste. Dithiocarbamate is a compound having one or more dithiocarbamic acid structures, and two sulfur atoms in dithiocarbamic acid coordinate with a heavy metal to form a chelate bond, thereby immobilizing the heavy metal.

According to a second aspect, in the heavy metal fixing agent according to the first aspect, the powdery dithiocarbamate is 1
It is characterized by being obtained by spray drying at 50 to 250 ° C.

According to the above means, the production conditions of the heavy metal immobilizing agent are optimized for efficiently producing the powder without impairing the reactivity when forming a chelate with the heavy metal.

A third aspect of the present invention is the heavy metal immobilizing agent according to the first or second aspect, wherein the powdery dithiocarbamate has an average particle size of 50 to 100 μm.

According to the above means, the range of the average particle size of the powder is optimized from the viewpoints of the handleability of the heavy metal fixing agent and the reaction efficiency with the waste.

The heavy metal immobilizing agent according to claim 4 is
It is characterized in that the dithiocarbamate and the water-absorbing substance are mixed to give a powder. Further, claim 7 uses kenaf or a water-absorbing polymer as the water-absorbing substance.

The heavy metal immobilizing agent according to claim 5 is
It is characterized in that the dithiocarbamate is mixed with at least one inorganic substance selected from silicate, phosphate, carbonate, sulfate and hydroxide to give a powder. Further, as a sixth aspect, the mixture of dithiocarbamate and an inorganic substance may further contain the above-mentioned water absorbing substance.

According to the above means, as the heavy metal immobilizing agent, an inorganic substance is used in addition to the dithiocarbamate. Here, silicates, phosphates, carbonates, sulfates, and hydroxides react with heavy metals to form heavy metal compounds having a lower solubility in water.

Further, an eighth aspect of the present invention is the heavy metal immobilizing agent according to the fifth or sixth aspect, wherein 5 to 20 parts by weight of dithiocarbamate is mixed with 100 parts by weight of the inorganic substance in a solid content ratio. And

According to the above means, the mixing ratio of the inorganic substance and the dithiocarbamate is optimized for the purpose of sufficiently fixing the heavy metal and suppressing the treatment cost.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The first embodiment of the heavy metal fixing agent according to the present invention is mainly composed of powdery dithiocarbamate. Dithiocarbamate is a compound having one or more dithiocarbamic acid structures, and two sulfur atoms in dithiocarbamic acid coordinate with heavy metals to form a chelate-bonded substance, thereby firmly fixing heavy metals. It is a thing. The following formula (Formula 1) shows the reaction mechanism between the dithiocarbamate and the heavy metal. In the formula, M represents a heavy metal atom and X represents an alkali metal or ammonium.

[0019]

[Chemical 1]

As the above-mentioned dithiocarbamate salt, any compound having at least one dithiocarbamic acid structure as shown in Chemical formula 1 can be used without particular limitation. Specific examples of dithiocarbamate salts applicable in the present invention are shown below. (1) A compound represented by the general formula (C _n H _{2n + 1} ) ₂ NCS ₂ Na): dimethyl dithio sodium carbamate diethyl diethyl dithio sodium carbamate dipropyl dithio sodium carbamate dibutyl dithio. - carbamic acid sodium pentyl-dithio sodium carbamic acid (2) in formula (C _n H _{2n + 1)} compound dimethyl dithio-carbamic acid potassium diethyl dithio-carbamate represented by ₂ NCS ₂ K) Potassium / dipropyl / dithio / potassium carbamate / dibutyl / dithio / potassium carbamate / dipentyl / dithio / potassium carbamate (3) Compounds represented by the general formula (C _n H _{2n + 1} ) ₂ NCS ₂ NH ₄ ) Dimethyl dithio ammonium carbamate diethyl diethyl dithio Ammonium carbamate, dipropyl dithiocarbamate, ammonium carbamate, dibutyl dithio-carbamate ammonium dipentyl-dithio-carbamate Ammonium
Etc. (4) Others • Piperidine • Dithio • Sodium carbamate • Piperidine • Dithio • Potassium carbamate • Piperidine • Dithio • Ammonium carbamate • Pyrrolidine • Dithio • Sodium carbamate • Pyrrolidine • Dithio • Potassium carbamate • Pyrrolidine • Dithio • Ammonium carbamate / morpholine / dithio / sodium carbamate / morpholine / dithio / potassium carbamate / morpholine / dithio / ammonium carbamate / thiazane / dithio / sodium carbamate / thiazane / dithio / potassium carbamate / thiazane / dithio / carbamic acid Ammonium, polyimine, dithio, sodium carbamate, polyimine, dithio, potassium carbamate, polyimine, dithio, carbamic acid Sodium salt, potassium salt, or ammonium salt of dithiocarbamic acid of an ammonium-pyrazine-based compound (as the pyrazine-based compound, pyrazine, dialkyl [C1-C4] pyrazine, 2,3,5,6-tetramethylpyrazine, 2- Methoxy-3-alkyl [C1-C
4] Pyrazine, 2-carboxylpyrazine, pyrazine-
2,3-dicarboxylic acid, dicyanopyrazine, 2,3-dicyanopyrazine, etc.) Sodium salt, potassium salt, or ammonium salt of dithiocarbamic acid of a piperazine compound (as the piperazine compound, piperazine, 1-
Methylpiperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 1-phenylpiperazine, 1,4-
Diphenylpiperazine, 1-methyl-4- (α, α′-
Diphenylmethyl) piperazine, 1-cinnamyl-4-
Diphenylmethylpiperazine, 1- (p-chlorobenzhydryl) -4- (m-methylbenzyl) piperazine,
1-aminoethylpiperazine, 1,4-bis (3'-aminopropyl) piperazine, 1- [alkyl (or alkenyl) aminoethyl] piperazine (C6-28), 1
-Methyl-4 '-(dimethylaminoethyl) piperazine, 1-aminoethylpiperazine alkylene (C1-
C4) oxod adduct, 1-aminoethylpiperazine
Alkyl (or alkylene / C1-C4) monoglycidyl ether adduct, N-aminoethylpiperazine / phenyl or tolyl monoglycidyl ether adduct, N-aminoethylpiperazine / acrylonitrile adduct, etc.) Piperazinium-1,4-piperazine dicarbodi Sodium salt of tetra (dithiocarboxy) tetraethylenepentamine, (ethyleneamino) dithiocarboxysodium-ethylenebenzylamine-ethyleneamine copolymer, etc.

The above-mentioned dithiocarbamate is characterized in that it is formed into a powder form. The method for making powder is not particularly limited, and various conventionally known methods can be used. Specific examples include spray dryers, spray dryers, drum dryers, band dryers and freeze dryers. Among them, spray drying is most preferably used in terms of efficiently obtaining uniform fine particles. Spray drying is a method of obtaining a powder by finely liquid-dispersing a solution of a dithiocarbamate, and bringing it into contact with a high temperature gas to dry it. It is important that the drying temperature at this time is within a temperature range in which the powder can be efficiently obtained and the reactivity of the dithiocarbamate is not lost. Specifically, it is preferably about 150 to 250 ° C., although it varies depending on the type of dithiocarbamate. That is, if the temperature is 150 ° C. or lower, the powder tends not to be efficiently obtained because the drying does not proceed, and at a temperature of 250 ° C. or higher, particularly higher than 280 ° C., the dithiocarbamate decomposes and loses reactivity. There is a fear that it is not preferable.

The particle size of the powdery dithiocarbamate obtained by the above various methods is not particularly limited, but is too small (50 μm).
(Below) before use as a fixing agent, it may become a factor of dust pollution by flying up into the air as dust, etc. If it is too large (100 μm or more), the kneading effect with waste will be adversely affected. Since it lowers and the immobilization efficiency of heavy metals lowers, which is not preferable, these are taken into consideration and appropriately set. Specifically, it is preferable that the average particle size of the powder is about 50 to 100 μm. The average particle size of the powder can be arbitrarily adjusted by, for example, changing the number of rotations of the spray nozzle during spray drying.

Another embodiment of the heavy metal immobilizing agent according to the present invention is dithiocarbamate and one or more inorganic substances selected from upper silicates, phosphates, carbonates, sulfates and hydroxides. And are mixed into a powder form. here,
As the dithiocarbamate, the above-mentioned powdery one may be mixed, or a liquid dithiocarbamate such as an aqueous solution and an inorganic substance may be mixed and appropriately dried to finally obtain a powdery one. good. When a liquid dithiocarbamate is used, by appropriately setting the mixing ratio with an inorganic substance, etc.
It is also possible to make the whole substantially into a powder state only by mixing with an inorganic substance.

Silicates, phosphates, carbonates, sulfates, and hydroxides all react with heavy metals in wastes to form heavy metal compounds, which have low solubility in water. As a result, the elution of harmful heavy metals can be suppressed. Since silicates, phosphates, carbonates, sulfates and hydroxides are much cheaper than dithiocarbamate, the treatment cost can be significantly reduced by combining these inorganic substances. In particular, it is effective for waste that contains a small amount of harmful heavy metals such as mercury, cadmium, hexavalent chromium, and arsenic, and that contains a large amount of lead, and a large amount of waste such as incineration fly ash generated from an municipal waste incinerator. Used.

The above-mentioned silicates, phosphates, carbonates, sulfates,
Examples of hydroxides include sodium silicate, calcium silicate,
Silicates such as magnesium silicate and aluminum silicate, (first, second and third) sodium phosphate, (first, second and third) potassium phosphate, ammonium phosphate, calcium phosphate, magnesium phosphate, aluminum phosphate and other phosphates , Calcium carbonate, magnesium carbonate, sodium carbonate, potassium carbonate,
Examples include carbonates such as sodium bicarbonate, sulfates such as calcium sulfate, magnesium sulfate, sodium sulfate, potassium sulfate, and sulfuric acid bands, hydroxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and barium hydroxide. However, the present invention is not limited to these.

The mixing ratio of the above-mentioned inorganic substance and dithiocarbamate is appropriately set. However, inorganic substances have a relatively weak binding force with heavy metals and cannot be completely immobilized. Therefore, if the proportion of inorganic substances is too high, depending on external conditions (such as acid rain or contact with alkaline waste), heavy metals may not be fixed. There is a case where the species become ions and are re-eluted from the processed material. This should be taken into consideration especially when the elution of a trace amount of heavy metal ions such as mercury, cadmium, lead, hexavalent chromium, and arsenic is a problem, and an appropriate mixing ratio should be selected in consideration of the treatment cost. To be done. Generally, the dithiocarbamate salt is added in an amount of 5 to 2 in terms of solid content to 100 parts by weight of the inorganic substance.
It is preferable to mix about 0 parts by weight. Therefore, for example, when using a dithiocarbamate aqueous solution having a concentration of 55 to 65% by weight, about 5 to 10 parts by weight is suitable for 100 parts by weight of the inorganic substance. With this ratio,
Even if it is not dried, only by mixing with an inorganic substance, the whole becomes substantially powdery.

Yet another embodiment of the heavy metal immobilizing agent according to the present invention is characterized in that a dithiocarbamate salt and a water-absorbing substance are mixed into a powder form. By using the water-absorbing substance together, for example, when mixed with a liquid dithiocarbamate, the whole can be easily made into a powder state. In addition, since the dithiocarbamate is supported by the water-absorbing substance, it easily stays in the object to be treated such as incinerated ash for a long period of time, and as a result, the treatment efficiency is improved.

As the water absorbing substance, various substances can be appropriately selected and used, and among them, kenaf or water absorbing polymer is particularly preferably used. Kenaf is an annual herb of the genus Hibiscus of the mallow family, which has a large water absorption per unit volume, and also has a high carbon dioxide adsorption capacity and a high absorption efficiency of nitrogen and phosphorus in the soil. Effectively acts on purification. As the water-absorbent polymer, conventionally known substances such as starch-based, cellulose-based, polyacrylic acid-based, poval-based, and polyoxyethylene-based can be appropriately selected and used.

The mixture of the dithiocarbamate salt and the water-absorbing substance may further contain the above-mentioned inorganic substance.

In addition to the above-mentioned dithiocarbamate, the inorganic substance and the water absorbing substance, other substances can be added to the heavy metal fixing agent of the present invention as described above. Specific examples thereof include talc and bentonite having a surfactant-like element, and ammonium chloride and ammonium carbonate having a buffer-like element.

When using the above heavy metal fixing agents,
To the waste containing heavy metals (for example, fly ash of refuse incineration plant), mix the powdery heavy metal fixing agent,
It is performed by adding an appropriate amount of water and kneading. The kneading facility and the kneading method are not particularly limited, and examples thereof include a container for storing waste (a hopper, etc.), a container for storing a heavy metal fixing agent (a hopper, etc.), and water for supplying an appropriate amount of water. The storage tank and the mixer for uniformly mixing each of these substances constitute a kneading facility, and an appropriate amount of waste and heavy metal immobilizing agent are charged into the mixer from the above two hoppers using a powder metering device. Then, an appropriate amount of water can be injected from the water storage tank and kneaded with the mixer for an appropriate time for treatment. The mixer is preferably a biaxial kneader mixer type or a vibrator mixer type in which a container is filled with vibrating balls.
Further, when it is desired to make the treated product into a solid shape, it is possible to mix an appropriate amount of Portland cement or the like.

In the above-mentioned kneading operation, unlike the conventional liquid organic chelating agent, there is no problem of scattering of the chemical liquid, and no bad odor or harmful gas is generated, which is preferable from the viewpoint of working environment. Also, in transportation, since the heavy metal immobilizing agent is powder, it can be transported by kraft bag packing, flexible container, or the like, and can be efficiently transported to the workplace at low cost. Further, since the heavy metal immobilizing agent of the present invention strongly fixes the heavy metals in the waste by forming a chelate bond, there is no risk of re-elution of heavy metal ions due to external conditions, and the heavy metals are included in the waste. Elution of trace amounts of harmful heavy metals (mercury, cadmium, lead, hexavalent chromium, arsenic, etc.)
It can be completely suppressed below the regulation value of the Prime Minister's Ordinance.

[0033]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto. (Example 1) 2 parts by weight of powdery pyrrolidine dithio sodium carbamate having an average particle diameter of 75 μm was added as a heavy metal immobilizing agent to 100 parts by weight of incinerated fly ash generated from an urban refuse cleaning plant as waste. After mixing in a kneader, 20 parts by weight of water was added and kneading was performed for about 5 minutes. The obtained treated product contains about 50w of slaked lime in the fly ash.
Since it contained t%, a hard lump was formed in about 1 hour after kneading. Subsequently, a dissolution test was performed on the above treated product.
Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 1. The <mark in the table indicates below the measurement limit.

[0034]

[Table 1]

(Example 2) 100 parts by weight of incinerated fly ash (fly ash) generated from a thermal power plant as waste was used as a heavy metal immobilizing agent and powdered dipropyl dithiocarbamic acid having an average particle diameter of 75 μm. After 0.5 part by weight of potassium and 3 parts by weight of a sulfuric acid band as a powdery inorganic substance were added and mixed in a kneader, 20 parts by weight of water was added and the mixture was kneaded for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 2. The <mark in the table indicates below the measurement limit.

[0036]

[Table 2]

(Example 3) 3 parts by weight of powdered piperidine dithio ammonium carbamate having an average particle diameter of 75 μm as a heavy metal immobilizing agent was added to 100 parts by weight of landfilled soil containing harmful heavy metals as waste. In addition, after mixing in a kneader, 20 parts by weight of water was added and kneading was performed for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 3. The <mark in the table indicates below the measurement limit.

[0038]

[Table 3]

(Example 4) 8 parts by weight of powdery potassium diethyldithio-carbamate having an average particle diameter of 75 μm as a heavy metal fixing agent against 100 parts by weight of molten fly ash generated from a melting furnace incinerator as waste. Then, 20 parts by weight of water was added and the mixture was kneaded for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 4. The <mark in the table indicates below the measurement limit.

[0040]

[Table 4]

(Example 5) 2 parts by weight of powdery dibutyl dithio diammonium carbamate having an average particle diameter of 75 μm as a heavy metal fixing agent, relative to 100 parts by weight of incinerated fly ash generated from an urban refuse cleaning plant as waste. Was added and mixed in a kneader, 20 parts by weight of water was added, and the mixture was kneaded for about 5 minutes. The obtained treated product contained about 50 wt% of slaked lime in the incineration fly ash, and thus became a hard lump about 1 hour after kneading. Subsequently, a dissolution test was performed on the above treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The dissolution test was conducted in 1973.
Analysis of the type and content of heavy metals in wastes was carried out according to JISK-0102, according to the Environmental Agency Notification No. 13. The results are shown in Table 5. The <mark in the table indicates below the measurement limit.

[0042]

[Table 5]

(Example 6) As a waste metal, 100 parts by weight of incinerated fly ash (fly ash) generated from a thermal power plant was used as a heavy metal immobilizing agent in the form of powdery polyimine / dithio / carbamic acid having an average particle diameter of 75 μm. After adding 0.5 part by weight of sodium and 3 parts by weight of a sulfuric acid band as a powdery inorganic substance and mixing in a kneader, 20 parts by weight of water was added and the mixture was kneaded for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 6. The <mark in the table indicates below the measurement limit.

[0044]

[Table 6]

(Example 7) 3 parts by weight of powdery morpholine dithio ammonium carbamate having an average particle diameter of 75 μm was added as a heavy metal immobilizing agent to 100 parts by weight of landfilled soil containing harmful heavy metals as waste. After mixing in a kneader, 20 parts by weight of water was added and kneading was performed for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 7. The <mark in the table indicates below the measurement limit.

[0046]

[Table 7]

(Example 8) As a waste, 100 parts by weight of molten fly ash generated from a melting furnace incineration facility was used as a heavy metal immobilizing agent in the form of powdery polyimine having an average particle size of 75 μm.
After 8 parts by weight of sodium dithiocarbamate was added and mixed in a kneader, 20 parts by weight of water was added and kneading was performed for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Also, regarding the waste before treatment, after analyzing the type and amount of heavy metals contained in the waste in advance,
The same dissolution test was performed. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 8. The <mark in the table indicates below the measurement limit.

[0048]

[Table 8]

(Example 9) As a waste metal, 100 parts by weight of incinerated fly ash generated from an urban refuse cleaning plant was used as a heavy metal immobilizing agent and powdered piperazine having an average particle size of 75 μm.
After adding 2 parts by weight of ammonium dithiocarbamate and mixing in a kneader, adding 20 parts by weight of water to about 5
It was kneaded for a minute. The obtained treated product contained about 50 wt% of slaked lime in the incineration fly ash, and thus became a hard lump about 1 hour after kneading. Subsequently, a dissolution test was performed on the above treated product. Also, regarding the waste before treatment, after analyzing the type and amount of heavy metals contained in the waste in advance,
The same dissolution test was performed. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 9. The <mark in the table indicates below the measurement limit.

[0050]

[Table 9]

(Example 10) As a waste metal, 100 parts by weight of incinerated fly ash (fly ash) generated from a thermal power plant was used as a heavy metal immobilizing agent and powdered dibutyl dithiocarbamic acid having an average particle diameter of 75 μm. Ammonium 0.5
By weight, 3 parts by weight of a sulfuric acid band as a powdery inorganic substance was added and mixed in a kneader, and then 20 parts by weight of water was added and kneading was performed for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 10. The <mark in the table indicates below the measurement limit.

[0052]

[Table 10]

(Example 11) 100 parts by weight of landfill contaminated soil containing harmful heavy metals as waste was used as a heavy metal immobilizing agent and powdered morpholine dithio.
After 3 parts by weight of potassium carbamate was added and mixed in a kneader, 20 parts by weight of water was added and kneaded for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 11. The <mark in the table indicates below the measurement limit.

[0054]

[Table 11]

(Example 12) As a waste metal, 100 parts by weight of molten fly ash generated from a melting furnace incineration facility was used as a heavy metal immobilizing agent and powdered piperazinium-1,4-piperazine dicarbodiate having an average particle diameter of 75 μm. After 8 parts by weight were added and mixed in a kneader, 20 parts by weight of water was added and kneading was performed for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 12. The <mark in the table indicates below the measurement limit.

[0056]

[Table 12]

(Example 13) 2 parts by weight of powdered piperazine / dithio / ammonium carbamate having an average particle size of 75 μm as a heavy metal immobilizing agent per 100 parts by weight of incinerated fly ash generated from an urban refuse cleaning plant as waste. Parts, equivalents of sodium phosphate and sodium carbonate as inorganic substances in powder form 1
After adding 0 part by weight and mixing in a kneader, 20 parts by weight of water was added and kneading was performed for about 5 minutes. The obtained treated product contained about 50 wt% of slaked lime in the incineration fly ash, and thus became a hard lump about 1 hour after kneading. Subsequently, a dissolution test was performed on the above treated product. Also, regarding the waste before treatment, the type of heavy metal contained in the waste in advance,
After analyzing the amount, a similar dissolution test was performed. The elution test was carried out in 1973 by the Environment Agency Notification No. 13, and the analysis of the type and content of heavy metals in wastes was carried out according to JISK-0102.
It was carried out according to. The results are shown in Table 13. The <mark in the table indicates below the measurement limit.

[0058]

[Table 13]

(Example 14) 100 parts by weight of incinerated fly ash (fly ash) generated from a thermal power plant as waste was used as a heavy metal immobilizing agent and powdered ammonium dibutyl dithiocarbamate 2 having an average particle size of 75 μm. By weight, 10 parts by weight of a sulfuric acid band as a powdery inorganic substance was added and mixed in a kneader, and then 20 parts by weight of water was added and kneading was performed for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 14. The <mark in the table indicates below the measurement limit.

[0060]

[Table 14]

(Example 15) 100 parts by weight of landfilled contaminated soil containing harmful heavy metals as waste was used as a heavy metal immobilizing agent and powdered morpholine dithio.
2 parts by weight of potassium carbamate, 10 parts by weight of sodium phosphate and potassium alum equivalent as powdered inorganic substances were mixed and mixed in a kneader, then 20 parts by weight of water was added and kneaded for about 5 minutes. Processed. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in accordance with JIS K-0102 in 1973, and the analysis of the type and content of heavy metals in the waste was carried out according to the Environmental Agency Notification No. 13. The results are shown in Table 15. The <mark in the table indicates below the measurement limit.

[0062]

[Table 15]

(Example 16) 100 parts by weight of molten fly ash generated from a melting furnace incineration facility as waste, and powdered piperazinium-1,4-piperazine dicarbodidide having an average particle diameter of 75 µm as a heavy metal fixing agent 2 parts by weight of anate, 10 parts by weight of an equivalent substance of sodium phosphate and aluminum sulfate as an inorganic substance in powder form and mixed in a kneader, and then water 2
0 parts by weight was added and kneading was performed for about 5 minutes. Subsequently, a dissolution test was performed on the obtained treated product. Further, with respect to the waste before treatment, the same elution test was performed after the kind and amount of the heavy metal contained in the waste were analyzed in advance. The elution test was carried out in 1973 by the Environment Agency Notification No. 13, and the analysis of the type and content of heavy metals in waste was JISK-0.
It was carried out according to 102. The results are shown in Table 16. The <mark in the table indicates below the measurement limit.

[0064]

[Table 16]

In any of Examples 1 to 16 above, no generation of harmful gases such as carbon disulfide, hydrogen sulfide and ammonia was observed during the kneading operation with the waste.

[0066]

As described above, since the heavy metal immobilizing agent of the present invention is in the form of powder, it has excellent handleability and can be transported efficiently and easily. Further, when kneading with the waste, there is no fear that harmful gas or the like will be scattered without being generated, so that the processing work can be easily carried out and the work environment is excellent. Furthermore, by using it together with an inorganic substance such as sulfate, the processing cost can be kept low while the heavy metal is sufficiently immobilized, and the practicality is excellent.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4D004 AA37 AA41 AB03 CA15 CA45                       CC06 CC11 CC15                 4G066 AA30D AA43D AA47D AA50D                       AB09B AB16B AC07B BA09                       BA20 BA36 CA43 CA46 DA20                       FA34 FA37

Claims (8)

[Claims] 1. A heavy metal immobilizing agent comprising a powdery dithiocarbamate. 2. The heavy metal fixing agent according to claim 1, wherein the powdery dithiocarbamate is 150 to 250.
A heavy metal immobilizing agent which is obtained by spray drying at ℃. 3. The heavy metal immobilizing agent according to claim 1, wherein the powdery dithiocarbamate has an average particle size of 5
A heavy metal immobilizing agent, which is 0 to 100 μm. 4. A heavy metal immobilizing agent characterized by mixing a dithiocarbamate and a water-absorbing substance into a powder form. 5. Immobilization of a heavy metal, characterized in that a powder of dithiocarbamate and one or more inorganic substances selected from silicates, phosphates, carbonates, sulfates and hydroxides are mixed into powder. Agent. 6. A powdery mixture of dithiocarbamate, one or more inorganic substances selected from silicates, phosphates, carbonates, sulfates and hydroxides, and a water-absorbing substance. Heavy metal immobilizing agent. 7. The heavy metal immobilizing agent according to claim 4 or 6, wherein the water absorbing substance is kenaf or a water absorbing polymer. 8. The heavy metal immobilizing agent according to claim 5, wherein dithiocarbamic acid is mixed in a solid content ratio of 5 to 20 parts by weight with respect to 100 parts by weight of the inorganic substance. Agent.