JP4901622B2 - Boiler ash treatment agent - Google Patents

Description

  The present invention relates to a boiler ash treatment agent.

  Boiler ash discharged from boilers fueled with paper sludge and coal, etc., separated and recovered as solids in waste liquid generated from pulp manufacturing processes, paper manufacturing processes, waste paper processing processes, etc. in paper mills is cement, concrete, Aggregates such as mortar, soil improvement materials, asphalt filler, tiles and tiles, admixtures of marine structures such as tetrapots, golf courses, ground drainage improving materials, water retention block materials, sewage / drainage treatment materials, etc. It is a resource that can be effectively used. However, the boiler ash produced by burning fuels such as coal, paper sludge, and wood chips contains a large amount of various substances such as boron, fluorine, selenium, and arsenic. In recent years, environmental standards have been strengthened in order to regulate. Under these circumstances, arsenic, selenium, fluorine and boron, especially fluorine and boron, are important for treatment. When reusing boiler ash, harmful substances such as boron are not eluted to cause environmental pollution. Need to be processed. In addition, when boiler ash is discarded, it is necessary to treat it so that harmful substances do not elute. As a method for treating harmful substances contained in boiler ash such as coal ash, lime and gypsum are added to the coal ash and kneaded to fix boron in the coal ash (Patent Document 1, Patent Document 2). ), A method of insolubilizing fluorine and boron by adding an insolubilizer containing calcium aluminate and calcium silicate to coal ash (Patent Document 3), adding a substance that elutes calcium ions in the presence of water to coal ash A method for fixing heavy metals, arsenic, selenium, sulfur and other harmful substances in coal ash (Patent Document 4), and harmful substances such as fluorine, arsenic, selenium and boron generated when producing zeolite from coal ash A method of precipitating and removing toxic substances by adding an alkaline earth metal salt to an alkaline waste liquid containing benzene has been proposed (Patent Document 5).

JP-A-11-116292 JP 2004-97944 A JP 2006-224025 A JP 2006-721 A JP 2005-95785 A

Coal ash contains boron, fluorine, selenium, arsenic, and the like as toxic substances that are likely to be eluted and cause pollution problems, but the methods described in Patent Documents 1 and 2 can fix boron. The ability to fix harmful substances such as fluorine, arsenic and selenium is insufficient, and the method described in Patent Document 3 can also immobilize fluorine and boron, but the ability to fix selenium and arsenic is insufficient. The method of Patent Document 4 has insufficient ability to immobilize fluorine and boron. The method described in Patent Document 5 can remove and purify all harmful substances such as fluorine, arsenic, selenium, and boron. However, this method uses a chemical treatment after transferring the harmful substances from coal ash to wastewater and separates them into solid and liquid. This is a wastewater treatment method that occurs during the reuse of coal ash to prevent toxic substances from leaching from solid coal ash even if the toxic substances in the wastewater can be below the wastewater standards. When applied to, it was difficult to make the amount of harmful substances eluted from coal ash below the environmental standard value. Furthermore, even if a large amount of chemicals was used and the amount of harmful substances eluted could be below the environmental standard value, the ability to immobilize harmful substances was insufficient, and there was a problem that harmful substances were eluted over time.
In addition, as a conventional wastewater treatment method, fluorine is known to be a calcium fluoride coprecipitation method or a hydroxide coprecipitation method. In fact, a fluorine two-stage precipitation treatment method combining these two methods, etc. The advanced processing method is a common method. In this method, a calcium salt such as slaked lime (calcium hydroxide) or calcium chloride is added as the first stage to produce and remove poorly soluble calcium fluoride, and an aluminum salt is added as the second stage. Thus, aluminum hydroxide is produced, and fluorine ions are adsorbed and co-precipitated on the floc. The advanced treatment method can reduce the fluorine in the wastewater below the wastewater standard value, but it is difficult to make it below the environmental standard value. As another advanced treatment, there is a method in which phosphoric acid is added to the waste water and the pH is adjusted to 12 with slaked lime to treat the fluorine to 5 mg / L or less. It is necessary to treat the added excess phosphoric acid separately after the fluorine treatment, and there is a problem that it is wasteful and impractical.
On the other hand, boron can be effectively treated by the combined use of the above-mentioned slaked lime and aluminum salt, but when fluorine is present in the wastewater, it becomes fluoroboron, and boron that has become fluoroboron is removed by ordinary coagulation precipitation Although it has been reported that a method of adding a calcium salt to the regenerated waste liquid removed by the ion exchange treatment and concentrating it to perform thermal decomposition, there are problems such as high processing costs. Selenium is also known as a coprecipitation method with iron (III) hydroxide, an adsorption method using activated alumina and activated carbon, a reduction method using metallic iron, and ferric chloride or sulfate bands for arsenic. There is known a coprecipitation method in which coprecipitation is carried out at pH 4 to 5 by using a solution. However, the coprecipitation method of selenium is less effective for selenium (VI), its removal rate is 10% or less, and the adsorption method is susceptible to interference with coexisting ions. The conventional reduction method has a problem that the amount of metallic iron used is large, and even though selenium can be reduced below the effluent standard value, it is difficult to make it below the environmental standard value. Moreover, none of the above methods alone can treat boron, fluorine, selenium, and arsenic at the same time, and complicated processes such as a combination of various methods are required. Furthermore, even if it is applied to prevent elution of harmful substances such as fluorine, boron, arsenic and selenium from solid boiler ash, harmful substances contained in solid waste such as boiler ash will remain There was a risk of gradual elution. In recent years, attempts have been made to immobilize harmful substances with layered inorganic minerals, etc., but natural substances such as layered inorganic minerals have poor stability, such as changes in crystal structure, and the ability to immobilize harmful substances is constant. In addition, the stability after fixing the harmful substance is poor, and the fixed harmful substance may be eluted again. For this reason, studies have been conducted to synthesize stable inorganic mineral-like compounds, but there are problems such as complicated manufacturing and high manufacturing costs, and in addition to simultaneously treating boron, fluorine, selenium, and arsenic. It is insufficient and has not been put into practical use. The present invention has been made in view of the above problems, and can reliably fix harmful substances such as boron, fluorine, selenium and arsenic in boiler ash, and can safely use boiler ash safely or by landfill. An object of the present invention is to provide a boiler ash treatment agent that can be disposed of.

That is, the present invention
(1) 40 to 95% by weight of alkaline earth metal hydroxide, 1 to 60% by weight of alkaline earth metal phosphate, layered crystalline aluminosilicate clay mineral, layered double hydroxide, amorphous and 0.1 to 40% by weight (alkaline earth metal ) of one or more clay minerals selected from quasicrystalline clay minerals and synthetics having the same composition and crystalline structure as these clay minerals A boiler ash treatment agent characterized by containing 100 wt% of hydroxide, alkaline earth metal phosphate, and clay mineral)
( 2 ) The boiler according to (1), further containing 0.01 to 10% by weight of a metal fixing agent based on the total amount of the alkaline earth metal hydroxide, alkaline earth metal phosphate, and clay mineral. Ash treatment agent,
Is the gist.

  The boiler ash treatment agent of the present invention is safe by immobilizing simultaneously and surely so that the amount of elution from the boiler ash of harmful substances such as selenium, arsenic, fluorine and boron in the boiler ash is below the environmental standard value. Can be processed. Boiler ash treated with the treatment agent of the present invention includes cement and other aggregates and soil improving materials, admixtures for offshore structures, golf courses, ground drainage improving materials, water retention block materials, sewage and wastewater treatment materials, etc. Can be safely and effectively used, and can be safely disposed of even if discarded without being reused.

  In the present invention, examples of the alkaline earth metal hydroxide include calcium hydroxide, magnesium hydroxide, barium hydroxide, beryllium hydroxide, strontium hydroxide, and radium hydroxide. Calcium hydroxide is particularly preferable. Examples of alkaline earth metal phosphates include calcium monohydrogen phosphate, calcium dihydrogen phosphate, calcium phosphate, magnesium monohydrogen phosphate, magnesium dihydrogen phosphate, magnesium phosphate, barium monohydrogen phosphate, dihydrogen phosphate Barium, barium phosphate, beryllium phosphate phosphate, beryllium phosphate phosphate, beryllium phosphate, strontium phosphate phosphate, strontium phosphate phosphate, strontium phosphate, radium phosphate phosphate, radium phosphate phosphate, Examples thereof include radium phosphate, and calcium monohydrogen phosphate, calcium dihydrogen phosphate, and calcium phosphate are preferable. Examples of clay minerals include layered crystalline aluminosilicate clay minerals such as kaolinite, dicalite, nacrite, and halloysite, layered double hydroxides such as hydrotalcite and hydrocalumite, amorphous clay minerals such as allophane, and imogolite. And the like, and synthetic compounds having the same composition and crystalline structure as these clay minerals, kaolinite, hydrotalcite and allophane are preferred, and hydrotalcite is particularly preferred.

The boiler ash treatment agent of the present invention comprises 40 to 95% by weight of the alkaline earth metal hydroxide, 1 to 60% by weight of alkaline earth metal phosphate, and 0.1 to 40% by weight of clay minerals ( However, the total of alkaline earth metal hydroxide, phosphate alkaline earth metal salt and clay mineral is 100% by weight). Since the appropriate treatment pH for selenium is 9 or more, the proper treatment pH for arsenic is 10.5 or more, and the proper treatment pH for boron is 11 or more, an alkaline earth metal is used to adjust the pH of boiler ash to 10 or more. Although it is necessary to add a hydroxide in the range of 40 to 95% by weight, the content is adjusted in accordance with the content and elution amount of each harmful substance within this range. Further, when the alkaline earth metal phosphate is less than 1% by weight, there is a possibility that the fixation of fluorine is particularly insufficient, and even if it is added in an amount exceeding 60% by weight, the effect is not significantly changed. On the other hand, when the clay minerals are less than 0.1% by weight, the adsorption and ion exchange of harmful substances cannot be sufficiently performed. It becomes difficult to fix the period, and re-elution may occur over time.
In treating boiler ash with the boiler ash treatment agent of the present invention, the amount of treatment agent added to the boiler ash is 0.1 to 50% by weight, preferably 0.1 to 10% by weight. Of harmful substances can be immobilized. By appropriately adjusting the composition ratio and addition amount of the boiler ash treatment agent of the present invention in accordance with the properties of the boiler ash, harmful substances can be reliably fixed and economically effective. For example, when the fluorine content in the boiler ash is high, increase the proportion of alkaline earth metal phosphate in the treatment agent, and when it is acidic and requires pH adjustment, or in the case of boiler ash with a high boron content The ratio of alkaline earth metal hydroxide is increased, and when the contents of arsenic, selenium, boron, and fluorine are low on average, the ratio of clay minerals is increased.

  Boiler ash fueled with coal, paper sludge and other heavy metals does not contain heavy metals, even if they contain harmful substances such as selenium, arsenic, boron, and fluorine. However, since boiler ash using heavy metals such as biomass and building waste as fuel contains heavy metals, the boiler ash treatment agent of the present invention further contains a metal fixing agent as necessary. It is preferable to contain, and when the boiler ash which used as a fuel what contains heavy metals, such as biomass and building waste material, elution of heavy metals from boiler ash can be prevented reliably. Any metal fixing agent may be used as long as it can form an insoluble compound with the heavy metal in the boiler ash. The metal fixing agent is preferably blended in an amount of 0.01 to 10% by weight of the total amount of alkaline earth metal hydroxide, alkaline earth metal phosphate, and clay mineral.

  Examples of the metal fixing agent include compounds having functional groups such as dithiocarbamic acid group, phosphoric acid group, carboxylic acid group, carbamic acid group, dithioic acid group, aminophosphoric acid group, thiol group, and xanthate group. The metal immobilizing agent used in the present invention may have the same functional group or may have two or more different functional groups. In addition, two or more kinds of metal fixing agents having different functional groups can be mixed and used, but the metal fixing agent preferably has water solubility and water dispersibility. Examples of the compound having a dithiocarbamic acid group include compounds obtained by reacting carbon disulfide with amines such as monoamines and polyamines. Examples of amines used for obtaining a metal scavenger having a dithiocarbamic acid group as a functional group include monoalkylamines such as monomethylamine, monoethylamine, monopropylamine, monoisopropylamine, monobutylamine and monoisobutylamine; Amine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, diisobutylamine, ethylmethylamine, methylpropylamine, isopropylmethylamine, butylmethylamine, isobutylmethylamine, ethylpropylamine, ethylisopropylamine, butylethylamine, ethylisobutyl Dialkylamines such as amine, isopropylpropylamine, butylpropylamine, butylisobutylamine; ethylenediamine, propylene Diamine, Butylenediamine, Hexamethylenediamine, Diethylenetriamine, Dipropylenetriamine, Dibutylenetriamine, Triethylenetetramine, Tripropylenetetramine, Tributylenetetramine, Tetraethylenepentamine, Tetrapropylenepentamine, Tetrabutylenepentamine, Pentaethylenehexamine, Aliphatic amines such as iminobispropylamine, monomethylaminopropylamine, methyliminobispropylamine; dialcohol amines such as dimethanolamine, diethanolamine, dipropanolamine, diisopropanolamine, dibutanolamine, diisobutanolamine; methylphenyl Amine, ethylphenylamine, phenylpropylamine, isopropylphenylamine, butylphenol Alkylphenylamines such as nylamine and isobutylphenylamine; morpholine; 2-methylmorpholine, 2-ethylmorpholine, 2-propylmorpholine, 2-isopropylmorpholine, 2-butylmorpholine, 2-isobutylmorpholine, 3-methylmorpholine, 3- Monoalkyl morpholines such as ethyl morpholine, 3-propyl morpholine, 3-isopropyl morpholine, 3-butyl morpholine, 3-isobutyl morpholine; 2,3-dimethyl morpholine, 2,5-diethyl morpholine, 2-ethyl-5-methyl morpholine Dialkylmorpholine such as 2,3,5-trimethylmorpholine, trialkylmorpholine such as 2,3-dimethyl-6-ethylmorpholine; 2,3,5,6-tetraethylmorpholine, 2-ethyl-3,5,6 -Trimethyl Tetraalkylmorpholines such as ruphorin; piperazine; 1-methylpiperazine, 1-ethylpiperazine, 1-propylpiperazine, 1-isopropylpiperazine, 1-butylpiperazine, 2-methylpiperazine, 2-ethylpiperazine, 2-propylpiperazine, 2 Monoalkylpiperazines such as isopropylpiperazine, 2-butylpiperazine, 2-isobutylpiperazine; dialkylpiperazines such as 2,3-dimethylpiperazine, 2,5-diethylpiperazine, 1,3-diethylpiperazine; 2,3,5- Trialkylpiperazines such as trimethylpiperazine, 1,2,5-trimethylpiperazine, 2,3-dimethyl-5-ethylpiperazine; 2,3,5,6-tetramethylpiperazine, 1,3,5,6-tetrapropyl Piperazine, 3-ethyl-2,5,6- Tetraalkylpiperazines such as limethylpiperazine; pyrrolidine; 2-methylpyrrolidine, 2-ethylpyrrolidine, 2-propylpyrrolidine, 2-isopropylpyrrolidine, 2-butylpyrrolidine, 2-isobutylpyrrolidine, 3-methylpyrrolidine, 3-ethylpyrrolidine Monoalkylpyrrolidines such as 3-propylpyrrolidine, 3-isopropylpyrrolidine, 3-butylpyrrolidine, 3-isobutylpyrrolidine; 2,3-dimethylpyrrolidine, 2,4-diethylpyrrolidine, 2-ethyl-3-methylpyrrolidine, etc. Dialkylpyrrolidines; trialkylpyrrolidines such as 2,3,4-trimethylpyrrolidine, 2,3-dimethyl-5-ethylpyrrolidine; 2,3,4,5-tetramethylpyrrolidine, 2-ethyl-3,4,5- Te, such as trimethylpyrrolidine Raalkylpyrrolidine; piperidine; 2-methylpiperidine, 2-ethylpiperidine, 2-propylpiperidine, 2-isopropylpiperidine, 2-butylpiperidine, 2-isobutylpiperidine, 3-methylpiperidine, 3-ethylpiperidine, 3-propylpiperidine Monoalkyl piperidines such as 3-isopropylpiperidine, 3-butylpiperidine, 3-isobutylpiperidine, 4-methylpiperidine, 4-ethylpiperidine, 4-propylpiperidine, 4-isopropylpiperidine, 4-butylpiperidine, 4-isobutylpiperidine Dialkylpiperidines such as 2,3-dimethylpiperidine, 2,5-diethylpiperidine, 2,4-dipropylpiperidine, 2-methyl-4-propylpiperidine; 2,4,6-trimethylpiperidine; Trialkylpiperidines such as 2,4-ethyl-6-propylpiperidine; Tetraalkylpiperidines such as 2,3,5,6-tetramethylpiperidine, 2,3,4,6-tetraethylpiperidine; 2,3,4,5 , 6-pentamethylpiperidine, 2,3,4,5,6-pentaethylpiperidine and other pentaalkylpiperidines; thiomorpholine; 2-methylthiomorpholine, 2-ethylthiomorpholine, 2-propylthiomorpholine, 2-isopropylthio Morpholine, 2-butylthiomorpholine, 2-isobutylthiomorpholine, 3-methylthiomorpholine, 3-ethylthiomorpholine, 3-propylthiomorpholine, 3-isopropylthiomorpholine, 3-butylthiomorpholine, 3-isobutylthiomorpholine, etc. Monoalkylthiomorpholine, 2,3-dimethyl Dialkylthiomorpholines such as luthiomorpholine, 2,5-diethylthiomorpholine, 2,6-dipropylthiomorpholine, 2-ethyl-3-methylthiomorpholine, 2-methyl-6-propylthiomorpholine; 2,3,5- Trialkylthiomorpholine such as trimethylthiomorpholine, 2,3,6-triethylthiomorpholine; tetraalkylthiomorpholine such as 2,3,5,6-tetramethylthiomorpholine, 2-ethyl-3,5,6-trimethylthiomorpholine, etc. Is mentioned.

  Also imidazolidine: 1-methylimidazolidine, 1-ethylimidazolidine, 1-propylimidazolidine, 1-isopropylimidazolidine, 1-butylimidazolidine, 1-isobutylimidazolidine, 2-methylimidazolidine, 2-ethylimidazolidine Lysine, 2-propylimidazolidine, 2-isopropylimidazolidine, 2-butylimidazolidine, 2-isobutylimidazolidine, 3-methylimidazolidine, 3-ethylimidazolidine, 3-propylimidazolidine, 3-isopropylimidazolidine, 3-Butylimidazolidine, 3-Isobutylimidazolidine, 4-Methylimidazolidine, 4-Ethylimidazolidine, 4-Propylimidazolidine, 4-Isopropylimidazolidine, 4-Butylimidazolidine, 4- Monoalkylimidazolidines such as sobutylimidazolidine, 5-methylimidazolidine, 5-ethylimidazolidine, 5-propylimidazolidine, 5-isopropylimidazolidine, 5-butylimidazolidine, 5-isobutylimidazolidine; 2,3 -Dialkylimidazolidines such as dimethylimidazolidine, 2,5-diethylimidazolidine, 4,5-dipropylimidazolidine, 1-methyl-4-propylimidazolidine; 2,4,5-trimethylimidazolidine, 3,4 A trialkylimidazolidine such as diethyl-5-propylimidazolidine; a tetraalkylimidazolidine such as 1,3,4,5-tetramethylimidazolidine, a 1,2,4,5-tetramethylimidazolidine; a pyrazolidine; 1 -Methylpyrazolidine, 1-ethylpyrazolid 1-propylpyrazolidine, 1-isopropylpyrazolidine, 1-butylpyrazolidine, 1-isobutylpyrazolidine, 2-methylpyrazolidine, 2-ethylpyrazolidine, 2-propylpyrazolidine, 2-isopropylpyrazolidine, 2-butylpyrazolidine, 2-isobutylpyrazolidine, 3-methylpyrazolidine, 3-ethylpyrazolidine, 3-propylpyrazolidine, 3-isopropylpyrazolidine, 3 -Butylpyrazolidine, 3-isobutylpyrazolidine, 4-methylpyrazolidine, 4-ethylpyrazolidine, 4-propylpyrazolidine, 4-isopropylpyrazolidine, 4-butylpyrazolidine, 4- Isobutylpyrazolidine, 5-methylpyrazolidine, 5-ethylpyrazolidine, 5-propylpyrazolidine, 5-isopropyl Monoalkylpyrazolidine such as rupyrazolidine, 5-butylpyrazolidine, 5-isobutylpyrazolidine; 3,4-dimethylpyrazolidine, 3,5-diethylpyrazolidine, 2,5-dipropylpyrazolidine Dialkylpyrazolidine such as 3-methyl-5-propylpyrazolidine; trialkylpyrazolidine such as 3,4,5-trimethylpyrazolidine, 2,4-diethyl-5-propylpyrazolidine; 2 , 3,4,5-tetramethylpyrazolidine, tetraalkylpyrazolidine such as 1,4-diethyl-3,5-dipropylpyrazolidine; pyrrole; 2-methylpyrrole, 2-ethylpyrrole, 2- Propyl pyrrole, 2-isopropyl pyrrole, 2-butyl pyrrole, 2-isobutyl pyrrole, 3-methyl pyrrole, 3-ethyl pyrrole, 3-propyl pyrrole Monoalkyl pyrrole such as 1,3-isopropyl pyrrole, 3-butyl pyrrole, 3-isobutyl pyrrole; 2,3-dimethyl pyrrole, 2,5-diethyl pyrrole, 2,4-dipropyl pyrrole, 2-ethyl-4 Dialkyl pyrrole such as methyl pyrrole and 2-methyl-3-propyl pyrrole; Trialkyl pyrrole such as 2,3,4-trimethyl pyrrole and 2,3,5-triethyl pyrrole; 2,3,4,5-tetramethyl Tetraalkylpyrrole such as pyrrole, 2-ethyl-3,4,5-trimethylpyrrole; imidazole; 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-isopropylimidazole, 2-butylimidazole, 2-isobutyl Imidazole, 4-methylimidazole, 4-ethylimidazole, -Propylimidazole, 4-isopropylimidazole, 4-butylimidazole, 4-isobutylimidazole, 5-methylimidazole, 5-ethylimidazole, 5-propylimidazole, 5-isopropylimidazole, 5-butylimidazole, 5-isobutylimidazole, etc. Dialkylimidazoles such as monoalkylimidazole, 2,4-dimethylimidazole, 2,5-diethylimidazole, 2,4-dipropylimidazole, 2-ethyl-4-methylimidazole, 2-methyl-5-propylimidazole; Trialkylimidazoles such as 4,5-trimethylimidazole, 2,4,5-triethylimidazole; pyrazole; 3-methylpyrazole, 3-ethylpyrazole, 3-propylpyrazole, 3-isopro Rupyrazole, 3-butylpyrazole, 3-isobutylpyrazole, 4-methylpyrazole, 4-ethylpyrazole, 4-propylpyrazole, 4-isopropylpyrazole, 4-butylpyrazole, 4-isobutylpyrazole, 5-methylpyrazole, 5-ethyl Monoalkylpyrazoles such as pyrazole, 5-propylpyrazole, 5-isopropylpyrazole, 5-butylpyrazole, 5-isobutylpyrazole, 3,4-dimethylpyrazole, 3,5-diethylpyrazole, 3,4-dipropylpyrazole, 3, A dialkylpyrazole such as ethyl-5-methylpyrazole; a trialkylpyrazole such as 3,4,5-trimethylpyrazole, 3,4,5-triethylpyrazole; phenylenediamine, o-, m-, p-xylylenediamine, 3, -Aromatic amines such as diaminochlorobenzene and aniline; cycloalkane polyamines such as 1,3-bis (aminomethyl) cyclohexane; polyethyleneimine, polypropyleneimine, poly-3-methylpropylimine, poly-2-ethylpropylimine, etc. A polymer of an unsaturated amine such as polyvinylamine and polyallylamine. It is also possible to copolymerize unsaturated amines such as vinylamine and allylamine with unsaturated amines such as dimethylacrylamide, styrene, methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, styrene sulfonic acid, and their salts. Copolymers with other monomers having a saturated bond are also included. These can also use 2 or more types of mixtures.

  In the compound having a dithiocarbamic acid group as a functional group, the dithiocarbamic acid group may be an acid type (terminal is a hydrogen atom), a salt type, or a compound containing both. Examples of the salt-type dithiocarbamic acid 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. A compound having a dithiocarbamic acid group as a functional group includes a compound having both an acid type and a salt type dithiocarbamic acid group, a compound having only an acid type dithiocarbamic acid group, and a salt type dithiocarbamic acid group only. One or a mixture of two or more compounds can be used.

  Examples of the compound having a phosphate group as a functional group include compounds having a phosphate group obtained by reacting the same amines as described above with aldehydes and phosphorous acid. In the compound having a phosphoric acid group as a functional group, the phosphoric acid group may be an acid type (terminal is a hydrogen atom), a salt type, or a compound containing both. Examples of the salt-type phosphate group include barium salt, sodium salt, potassium salt, calcium salt, magnesium salt, and amine salt, and sodium salt and potassium salt are usually preferable. As a compound having a phosphate group as a functional group, a compound having both an acid type and a salt type phosphate group in one molecule, a compound having only an acid type phosphate group, and a salt type phosphate group only. One kind or a mixture of two or more kinds of the compounds having them can be used.

  Examples of the compound having a carboxylic acid group as a functional group include compounds having a carboxylic acid group obtained by reacting the same amines as described above with a monohalogenated carboxylic acid or an ester thereof. In the compound having a carboxylic acid group as a functional group, the carboxylic acid group may be an acid type (terminal hydrogen atom), a salt type, or a compound containing both. Examples of the salt-type carboxylic acid group include barium salts, sodium salts, potassium salts, calcium salts, magnesium salts, and amine salts, but sodium salts and potassium salts are usually preferable. As a compound having a carboxylic acid group as a functional group, a compound having both an acid type and a salt type carboxylic acid group in one molecule, a compound having only an acid type carboxylic acid group, and a salt type carboxylic acid group only. One kind or a mixture of two or more kinds of the compounds having them can be used.

  A commercially available metal collector may be used as the metal collector, and examples of commercially available metal collectors include Ashclean C-500, Ashclean C-508, and Ashclean C-505 (stocks). Ebara Manufacturing Co., Ltd.), Ash Knight S-803 (Kurita Industry Co., Ltd.), TX-10, TS-500, TS-600, TS-800, (Tosoh Corporation), Alcite L-105 (Fuji Sash Corporation) ), Koei Chelate 200 (Lasa Soei Co., Ltd.), Ash Ace L-5000 (Hitachi Shipbuilding Co., Ltd.), UML-7200, UML-8100, UML-8100A (Unitika Ltd.), ALM-648HG, Heidion-VG ( Nippon Soda Co., Ltd.), Epoflock series (Epofuloc L-1 and Epofloc L-2) manufactured by Miyoshi Oil & Fat Co., Ltd. ), Epo Luba series (NEW Eporuba 800, NEW Eporuba 800A, NEW Eporuba 810, etc.), include the Epoasshu M-1 and the like.

  The boiler ash to be treated by the treatment agent of the present invention includes, for example, coal ash discharged from a thermal power plant, paper sludge that is a fiber residue generated in a paper manufacturing process, wood chips, livestock Waste, food waste, construction waste wood, sawmill residue, black liquor (pulp factory waste), sewage sludge, human waste sludge, rice straw, straw, rice husk, forest land residue (thinned wood, damaged trees, etc.), sugar cane And corn crops such as corn and oil crops such as rapeseed, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples.
Examples 1-6, Comparative Examples 1-9
For 100 g of boiler ash with pH 9.8 (according to Environmental Agency Notification No. 46 test method) containing 4.8 mg / kg of selenium, 5.2 mg / kg of arsenic, 150 mg / kg of boron and 40 mg / kg of fluorine as harmful substances 20% by weight of water was added, and the chemicals shown in Table 1 were added and kneaded for 5 minutes. About the boiler ash after a process, and the unprocessed boiler ash, the elution density | concentration of a hazardous | toxic substance was measured according to the Environmental Agency Notification No.46 test. Table 2 shows the results of the toxic substance elution test from the boiler ash immediately after the treatment with the chemical mixed with the boiler ash. Table 3 shows the results of the dissolution test after 7 days of treatment.

(Table 1)

(Table 2)

(Table 3)

Claims (2)

40 to 95% by weight of alkaline earth metal hydroxide, 1 to 60% by weight of alkaline earth metal phosphate, layered crystalline aluminosilicate clay mineral, layered double hydroxide, amorphous and quasicrystalline 0.1 to 40% by weight of one or more clay minerals selected from clay minerals and composites having the same composition and crystalline structure as these clay minerals (however, alkaline earth metal hydroxides) Boiler ash treating agent, characterized in that the total of alkaline earth metal phosphates and clay minerals is 100% by weight. The boiler ash treatment agent according to claim 1, further comprising 0.01 to 10% by weight of a metal fixing agent based on a total amount of the alkaline earth metal hydroxide, the alkaline earth metal phosphate and the clay mineral. .