JP4596565B2 - Heavy metal immobilization treatment composition and heavy metal immobilization treatment method - Google Patents

Description

  The present invention relates to a heavy metal immobilizing agent composition that can safely and reliably insolubilize heavy metals contained in waste.

  There are various types of solid substances such as fly ash and incineration ash generated at garbage incinerators, dust, mines discharged from mines, activated sludge generated during wastewater treatment, and contaminated soil such as ruins of chemical factories. It contains metals and may contain a large amount of heavy metals that are harmful to the human body, such as mercury, cadmium, lead, zinc, copper, and chromium. When heavy metals are eluted from solid substances into groundwater, rivers, and seawater, serious environmental pollution is a problem.

  For this reason, it has been proposed to immobilize heavy metals with a heavy metal immobilizing agent before final disposal of solid waste by landfill, etc., because of its excellent ability to collect mercury and cadmium. A dithiocarbamic acid type heavy metal immobilizing agent having a dithiocarbamic acid group or a salt thereof as a functional group is widely used as a heavy metal immobilizing agent. However, the dithiocarbamate-type heavy metal immobilization treatment agent has the advantage of excellent trapping power for mercury, cadmium and the like, but it tends to generate toxic gases such as carbon disulfide when added to fly ash. There was a problem that there was something. Recently, the Ministry of Health, Labor and Welfare has confirmed that carbon disulfide is generated from most of the heavy metal immobilization treatment agents currently used. The company has been instructed to take measures to replace heavy metal immobilizing agents with those that do not easily generate carbon disulfide, and it is desirable to use heavy metal immobilizing agents that generate less carbon disulfide. Yes. From such a viewpoint, a method for stabilizing the heavy metal immobilization treatment agent by adding an amine to the dithiocarbamic acid type heavy metal immobilization treatment agent has been proposed (Patent Document 1).

Japanese Patent No. 3455363

  However, although the method described in Patent Document 1 can suppress the generation of carbon disulfide when added to waste such as fly ash, amines generally have high toxicity and sensitization, and heavy metal immobilization treatment is possible. When a chemical agent and a highly volatile low molecular weight amine are used in combination, the amine is likely to scatter, causing an amine odor when disposing of the waste, causing discomfort, causing environmental pollution in the surrounding area, and possibly causing harm to the human body. is there. On the other hand, when a high molecular weight amine is added, the long-term stability of the heavy metal immobilization treatment agent may be reduced, or the long-term stability of the metal immobilization performance by the heavy metal immobilization treatment agent may be impaired. In this case, there is a risk of contaminating the surrounding environment during waste disposal.

  The object of the present invention is to solve the above-mentioned problems of the prior art and to provide a heavy metal-immobilized treating agent composition capable of safely treating waste.

That is, the present invention
(1) Dithiocarbamic acid type heavy metal immobilizing agent (A) in which a dithioacid group or a salt thereof is bonded to nitrogen of an amine selected from diethylamine, diethylenetriamine, tetraethylenepentamine, piperazine, polyethyleneimine / benzyl chloride condensate And amino groups of amines selected from glycine, sarcosine, β-alanine, DL-alanine (b1), ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylenimine / benzyl chloride condensate, and piperazine. Compound (b2) obtained by introducing a propanoic acid group so that one or more primary and / or secondary amino groups remain, Glycine having one primary amino group among the compounds of (b1) above , Β-alanine, DL-alanine amino group, secondary amino Included in the group of compounds (b3) into which a propanoic acid group or a hydroxymethyl group has been introduced so that one group remains, combined with a dithiocarbamic acid type heavy metal immobilizing agent, suppresses the generation of carbon disulfide and amine A heavy metal immobilizing treatment agent comprising at least one (B) selected from amino acid compounds having one or more primary and / or secondary amino groups , or alkali metal salts of the amino acid compounds Composition,
(2) Carbon disulfide, a method for immobilizing a heavy metal in fly ash by suppressing the generation of amine, adding the heavy metal immobilization agent composition according to claim 1 to the fly ash together with water, A heavy metal immobilization treatment method characterized by kneading,
Is a summary.

  According to the heavy metal immobilizing agent composition of the present invention, when insolubilizing heavy metals in waste, there is no generation of unpleasant odors, problems of contamination of the work environment, or harm to the human body, and the safety and The heavy metal in the waste can be reliably insolubilized. The heavy metal immobilizing agent composition of the present invention does not generate carbon disulfide, carbonyl sulfide, amine, or the like when added to waste such as fly ash. Further, by using an amino acid or an amino acid alkali metal salt in combination with a heavy metal immobilizing agent, water solubility can be increased or the amount added during the treatment can be increased, and the long-term stability of the product can be improved.

Examples of the dithiocarbamic acid type heavy metal immobilization treatment agent (A) in the present invention include compounds obtained by reacting carbon disulfide with amines and introducing a dithioacid group or a salt thereof into the nitrogen of the amines. Amines, for example, di-ethylamine, di- ethylene triamine, Te tiger pentamine, pin Perazine, Po Li ethyleneimine-benzyl chloride condensate, and the like. These can also use 2 or more types of mixtures.

  The dithiocarbamic acid type heavy metal immobilizing agent (A) is a compound in which a dithioic acid group is bonded to a nitrogen atom of an amine (acid type functional group) or a compound in which a salt of a dithioic acid group is bonded (salt type functional group). good. Further, two or more dithioic acid groups or dithioic acid group salts may be introduced in one amine molecule. In the case of a compound having two or more dithioic acid groups or dithioic acid group salts, it may have only dithioic acid groups or only dithioic acid group salts, or both. May be. Examples of the salt-type functional group include barium salt, sodium salt, potassium salt, calcium salt, magnesium salt, amine salt and the like, but sodium salt and potassium salt are usually preferable. Such a compound can be obtained by reacting an amino compound with carbon disulfide, and the reaction between the amino compound and carbon disulfide is performed in the presence of an alkali such as the above-mentioned metal hydroxide or a reaction. A compound having a salt-type functional group can be obtained by subsequent treatment with alkali. The dithiocarbamic acid type heavy metal immobilization treatment agent can be used in combination of two or more compounds.

In the present invention, as in combination with a dithiocarbamate-type heavy metal immobilization treatment agent carbon disulfide, one or more primary suppressing generation of amine and / or amino acid compounds that have a secondary amino group (B) is , glycine, sarcosine, beta-alanine, DL-alanine (b1); ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine benzyl chloride condensate, the amines amino group selected from piperazine, 1 A compound (b2) obtained by introducing a propanoic acid group so that one or more secondary and / or secondary amino groups remain, glycine having one primary amino group among the compounds of the above (b1), β -Propanic acid group or hydroxymethyl group so that one secondary amino group remains in the amino group of alanine or DL-alanine Included in the group of the introduced compound (b3), amino acid compounds having one or more primary and / or secondary amino groups, or Ru at least one can be mentioned selected from alkali metal salts of the amino acid compound. As a method for introducing an alkyl carboxyl group with an amine, a method of introducing a haloalkyl carboxylic acid active hydrogen primary amine, a method of adding (meth) acrylic acid, or halo alkyl carboxylic acids, (meth) acrylic acid alkyl ester The method of hydrolyzing an ester or a nitrile group after adding acrylonitrile is mentioned. A compound in which a propanoic acid group or a hydroxymethyl group is introduced into the amino acid compound having one primary amino group is preferred because the effect of suppressing carbon disulfide generation is higher.

The heavy metal immobilization treatment composition of the present invention includes the above-described dithiocarbamic acid type heavy metal immobilization treatment agent (A) and at least one selected from an amino acid compound and an alkali metal salt (B) of an amino acid compound. Among the alkali metal salt of the amino compound or amino acid compound (B), glycine, alanine, Sarukoshi N'ya, these alkali metal salts. The present heavy metal immobilization treatment composition does not generate carbon disulfide, carbonyl sulfide, amine, etc., and further, when unreacted raw material amines remain in the heavy metal immobilization treatment composition, An amine may be released and an unpleasant odor may be generated. However, when an amino acid of the above amino acids or amino acid alkali metal salts is added to a heavy metal immobilizing agent to adjust the heavy metal immobilizing agent composition, Generation | occurrence | production is suppressed and the surrounding environmental pollution at the time of heavy metal fixed treatment agent composition manufacture can be prevented. In addition, amine odors and ammonia odors may also be generated when metals in fly ash are treated. Addition of the above amino acids together with heavy metal immobilizing agents suppresses the generation of amine odors and ammonia odors during processing. can do.

  In the method of the present invention, a dithiocarbamic acid type heavy metal immobilizing agent (A) and an amino acid compound having a primary and / or secondary amino group or an alkali metal salt (B) of an amino acid compound (primary and / or secondary amino) The amino acid compounds having a group and the alkali metal salts of these amino acid compounds may be collectively referred to as amino acid compounds.) May be added to waste simultaneously or separately, but dithiocarbamic acid When the type heavy metal immobilization treatment agent is added to the waste, it is preferable that amino acid compounds are present in the waste. For this reason, it is preferable to add amino acid compounds prior to the heavy metal immobilizing agent or at the same time as the heavy metal immobilizing agent. In addition, when a heavy metal immobilization treatment composition in which a dithiocarbamic acid type heavy metal immobilization treatment agent and an amino acid compound having primary and / or secondary amino groups are mixed in advance is added to waste, the treatment effect and Efficient processing can be performed in terms of workability. Examples of the method of adding the heavy metal immobilizing agent and the amino acid compound (or the heavy metal immobilizing agent composition obtained by mixing both) to the waste include, for example, a method of spraying these aqueous solutions and suspensions. The proportion of amino acid compounds having a primary and / or secondary amino group is preferably 0.001 to 50% by weight, particularly 0.01 to 15% by weight, based on the total amount of the heavy metal immobilizing agent and the amino acid compound. % Is preferred. The amount of the dithiocarbamic acid type heavy metal immobilization treatment agent added to the waste is preferably 0.1 to 50% by weight in terms of anhydride.

  The heavy metal immobilizing agent composition of the present invention is suitable for the treatment of waste containing heavy metals, such as solid waste such as slag, soil, fly ash, waste water, exhaust gas, etc. It is suitable as a method. Examples of heavy metals that can be treated with the heavy metal fixing treatment composition of the present invention include lead, cadmium, hexavalent chromium, arsenic, selenium, mercury, nickel, molybdenum, antimony, copper, zinc, manganese, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples. The dithiocarbamic acid type heavy metal immobilizing agents used in the following examples and comparative examples are as follows.
(1) Heavy metal immobilization treatment agent A: potassium N, N-diethylamine-N-carbodithioate.
(2) Heavy metal immobilization treatment agent B: diethylenetriamine-N, N ′, N ″ -sodium triscarbodioate.
(3) Heavy metal immobilization treatment agent C: tetraethylenepentamine-N, N ′, N ″, N ″ ″-sodium tetracarbodithioate.
(4) Heavy metal fixing treatment agent D: potassium piperazine-N, N′-biscarbodithioate.
(5) Heavy metal immobilization treatment agent E: Polyethyleneimine / benzyl chloride condensate compound obtained by introducing sodium dithioate into nitrogen and tetraethylenepentamine-N, N ′, N ″, N ′ ″-tetracarbodithio 1: 8 (weight ratio) mixture of sodium acid.
(6) Heavy metal immobilization treatment agent F: 1:10 (weight ratio) mixture of a compound in which potassium dithioate is introduced into nitrogen of polyethyleneimine / benzyl chloride condensate and potassium piperazine-N, N′-biscarbodithioate .

Examples 1-8
0.8 g of heavy metal immobilizing agent composition (as anhydride) in which the dithiocarbamic acid type heavy metal immobilizing agent shown in Table 1 and amino acid compounds were mixed at a ratio shown in the same table per 100 g of fly ash generated by garbage incineration ) And water were added to a total amount of 20 g and kneaded for 10 minutes. Table 1 shows the results of measuring the amount of metal elution from the treated fly ash based on the Environmental Agency Notification No. 13 test method. The results of measuring the amount of carbon disulfide generated by the following measurement method are also shown in Table 1.

Method for measuring carbon disulfide generation amount After charging 20.0 g of alkaline fly ash into a sealed 500 ml four-necked flask and substituting with nitrogen, 0.4 g (as anhydride) of the heavy metal immobilizing agent and the total amount of water is 30 It adjusted to 0.0g, and it melt | dissolved uniformly, and added to the fly ash. After the addition, the mixture was stirred at 60 ° C. for 15 minutes, and the amount of carbon disulfide generated was measured with a carbon disulfide detector tube (manufactured by Gastec Co., Ltd.).

Comparative Examples 1-6
The fly ash was treated in the same manner as in Examples 1 to 8, except that 100 g of the heavy metal immobilizing agent shown in Table 1 was added per 100 g of fly ash. The amount of metal elution from the treated fly ash was measured in the same manner as in Examples 1-8. The measurement results of the amount of carbon disulfide generated are also shown in Table 2.

For Examples 1 and 2 and Comparative Example 1 using the heavy metal immobilizing agent A, the amount of amine generated was also measured, and the results are shown in Tables 1 and 2. The amount of amine generated was measured using an amine detector tube (manufactured by Gastec Co., Ltd.) in the same manner as the amount of carbon disulfide generated. In addition, the amine generation amount was not measured about the Example using the heavy metal fixing agents BF, and a comparative example.

Claims (2)

Dithiocarbamic acid type heavy metal immobilizing agent (A) in which a dithioacid group or a salt thereof is bonded to nitrogen of an amine selected from diethylamine, diethylenetriamine, tetraethylenepentamine, piperazine, polyethyleneimine / benzyl chloride condensate , and Primary to the amino group of amines selected from glycine, sarcosine, β-alanine, DL-alanine (b1), ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylenimine / benzyl chloride condensate, piperazine And / or compound (b2) obtained by introducing a propanoic acid group so that one or more secondary amino groups remain, glycine having one primary amino group among the compounds of (b1) above, β- Secondary amino groups are added to the amino groups of alanine and DL-alanine. One that is included in the group of compounds (b3) having a propanoic acid group or a hydroxymethyl group introduced so that one remains, and that suppresses the generation of carbon disulfide and amine in combination with a dithiocarbamic acid type heavy metal immobilizing agent. A heavy metal immobilizing agent composition comprising the above amino acid compound having a primary and / or secondary amino group , or at least one (B) selected from alkali metal salts of the amino acid compound. A method of immobilizing heavy metal in fly ash while suppressing the generation of carbon disulfide and amine, and adding the heavy metal immobilizing agent composition according to claim 1 to fly ash together with water and kneading. A heavy metal immobilization method characterized by the above.