JP2002028605A - Treating agent and treating method for solid waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solid waste treating agent and to provide a treating method of solid waste capable of making the solid waste containing harmful metals or organic materials such as dioxins or oil surely and efficiently harmless. SOLUTION: The solid waste treating agent is composed of a mixture of a metal collecting agent and a surfactant. The treating method of the solid waste is performed by adding the mixture of the metal collecting agent and the surfactant into the solid waste to fix the metals in the solid waste by the metal collecting agent and washing and removing the organic material in the solid waste.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for safely removing harmful metals, chlorinated substances such as dioxins, oils, and the like, which are present in solid wastes such as incinerated ash, dust, slag, sludge, soil, shredder dust, and the like. The present invention relates to a solid waste treatment agent and a solid waste treatment method capable of detoxifying solid waste by treating the same.

[0002]

2. Description of the Related Art Solid waste such as dust generated in a garbage incineration plant, slag discharged from a mine, activated sludge used in the treatment of wastewater, and contaminated soil is used. Contains various metal elements, and often contains heavy metal elements harmful to the human body, such as mercury, cadmium, lead, zinc, copper, and chromium. When metals are eluted from these solid wastes, there is a possibility that groundwater, rivers, seawater, etc. will be contaminated. In recent years, harmful chlorinated substances such as dioxins may be contained in these wastes, which has become a major social problem.

For this reason, in recent years, a metal collecting agent has been added to solid waste such as dust, slag, sludge, soil and the like contaminated with metal, and the metal in the solid waste has been fixed by the metal collecting agent. In addition, there is a method of treating a solid waste so as not to be eluted.

However, according to this method, the reaction between the metal collecting agent and the metal in the solid waste is not always sufficiently performed due to the low penetration of the metal collecting agent into the solid waste. As a result, there has been a case where the metal contained in the solid waste cannot be reliably fixed.

On the other hand, methods for removing chlorinated substances such as dioxins contained in wastes include a heat dechlorination method, a method using ozone and ultraviolet rays in combination, and a method for dissolving supercritical water under high temperature and high pressure. There is known a method of decomposing dioxins in solid waste by a method utilizing the decomposition characteristics and the like. However, since these methods require treatment under special conditions such as high temperature and high pressure,
Investment in processing equipment and maintenance cost of the equipment are required, and it is difficult to sufficiently decompose dioxins in solid waste, and there is a risk that a large amount of undecomposed dioxins may remain.

[0006] Further, the solid waste sometimes contains a large amount of organic substances such as oil. However, since conventional processing methods cannot remove organic substances such as oil from solid waste, when solid waste is landfilled and finally disposed of, such as by dumping into the ocean, oil and other substances are removed from solid waste. There is a possibility that the organic matter is eluted to cause environmental pollution.

[0007] The present invention has been made in view of the above points,
To provide a solid waste treatment agent and a solid waste treatment method capable of reliably and efficiently detoxifying solid waste containing harmful metals and organic substances such as dioxins and oils. Aim.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, by using a metal collecting agent and a surfactant together, the metal collecting agent can effectively penetrate into solid waste. Metal in solid waste can be reliably immobilized, and organic substances such as dioxins and oils can be washed and removed from solid waste by the action of surfactants to make the solid waste harmless. They have found that they can do this and have completed the present invention.

[0009]

That is, the solid waste treating agent of the present invention is characterized by comprising a mixture of a metal collecting agent and a surfactant. Further, the method for treating solid waste of the present invention, a mixture of a metal collecting agent and a surfactant is added to the solid waste, and the metal in the solid waste is fixed by the metal collecting agent, It is characterized by washing and removing organic substances in solid waste.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As a metal collecting agent constituting the solid waste treating agent of the present invention, a group capable of forming a complex with a metal, for example, a coordination to a metal such as an oxygen atom, a nitrogen atom, a sulfur atom, etc. Examples of the compound having a group containing a functional atom include a compound having a functional group such as an amino (imino) phosphate group, an amino (imino) carboxylic acid group, and a dithiocarbamic acid group. As the metal collecting agent, those having water solubility and water dispersibility are preferable, and a compound having a dithiocarbamic acid group is particularly preferable because of its excellent ability to collect heavy metals such as mercury.

The compound having an amino (imino) phosphate group as a functional group can be obtained by, for example, reacting an amine such as a monoamine or a polyamine with an aldehyde or a phosphorous acid under acidic conditions. Imino) a compound having a carboxylic acid group as a functional group is reacted with an amine such as a monoamine or a polyamine, and a monohalogen carboxylic acid or an ester thereof, or a carboxylic acid or an ester having a vinyl group, or acrylonitrile or methacrylonitrile. If necessary, it can be obtained by performing a hydrolysis reaction or the like. The compound having a dithiocarbamic acid group as a functional group can be obtained by reacting amines such as monoamine and polyamine with carbon disulfide.

The monoamine includes monomethylamine, dimethylamine, monoethylamine, diethylamine, monopropylamine, dipropylamine, monobutylamine, dibutylamine, isopropylamine, diisopropylamine, piperidine, piperazine, morpholine, methylphenylamine, ethyl Phenylamine and the like. Examples of the polyamine include, for example, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenetriamine, dibutylenetriamine, triethylenetetramine, tripropylenetetramine, tributylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, Aliphatic polyamines such as tetrabutylenepentamine, pentaethylenehexamine, iminobispropylamine, monomethylaminopropylamine and methyliminobispropylamine; cycloalkane-based polyamines such as 1,3-bis (aminomethyl) cyclohexane;
Piperazines such as 1-aminoethylpiperazine and piperazine; polymers of cyclic imines such as polyethyleneimine, polypropyleneimine, poly-3-methylpropylimine and poly-2-ethylpropylimine; polyvinylamine;
Examples include polymers of unsaturated amines such as polyallylamine. In addition, unsaturated amines such as vinylamine and allylamine, and unsaturated amines that can be copolymerized with unsaturated amines such as dimethylacrylamide, styrene, methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, styrene sulfonic acid, and salts thereof. Copolymers with other monomers having a saturated bond are also included.

The above amines include a hydroxyalkyl group,
Those having an acyl group, an alkyl group or the like as the N-substituent may be used. The N-hydroxyalkyl substituent can be introduced by reacting the amines with an epoxy alkane; the N-acyl substituent is introduced by reacting the amines with a fatty acid; N
An alkyl substituent is introduced by reacting the amines with an alkyl halide; The N-hydroxyalkyl substituent preferably has 2 to 28 carbon atoms in the alkyl group, and the N-acyl substituent preferably has 2 to 26 carbon atoms.
It is preferred that The N-alkyl substituent preferably has 2 to 22 carbon atoms.

Further, a polycondensed polyamine obtained by polycondensation of the above amines and epihalohydrin and a polycondensed polyethyleneimine can also be used. Epihalohydrin includes epichlorohydrin, epibromohydrin, epiiodohydrin and the like. The amines may be other than those described above as long as they have an active hydrogen atom bonded to a nitrogen atom and can react with carbon disulfide to form a dithiocarbamic acid group.

A hydroxyalkyl group to the above amines,
The reaction for introducing an N-substituent such as an acyl group or an alkyl group or the polycondensation reaction between an amine and epihalohydrin may be performed before or after the reaction between the amine and carbon disulfide. When the reaction is performed before the reaction with carbon, an N-substituent is introduced into the amines, or after the polycondensation of the amines with epihalohydrin, the dithiocarbamic acid group is formed by reacting with carbon disulfide. It is necessary that active hydrogen atoms that can be formed remain in the amines.

The reaction between amines and carbon disulfide can be carried out by, for example, dissolving the amines in a solvent such as water or alcohol, and adding carbon disulfide to the reaction to react. The dithiocarbamic acid type functional group may be an acid type or a salt type, and after completion of the reaction, a hydroxide or carbonate of an alkali metal (eg, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, etc.) )
Alkaline earth metal hydroxides and carbonates (for example, calcium hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, etc.) or alkali such as ammonia, or the reaction of amines with carbon disulfide, By performing the reaction in the presence of these alkalis, a metal collector having a salt type dithiocarbamic acid type functional group can be obtained.

The metal collecting agent having a dithiocarbamic acid group is not limited to the above, and may be, for example, a compound having another functional group in addition to a dithiocarbamine type functional group. Among the metal collectors having a dithiocarbamic acid group, dimethyldithiocarbamic acid and salts thereof,
Diethyldithiocarbamic acid and its salts, ethylenediamine-polydithiocarbamic acid and its salts, diethylenetriamine-polydithiocarbamic acid and its salts, triethylenetetramine-polydithiocarbamic acid and its salts, tetraethylenepentamine-polydithiocarbamic acid and its salts, polyethyleneimine -Polydithiocarbamic acid and its salts are preferred.

The above-mentioned metal collecting agent can be used alone or in combination of two or more different compounds. Further, the metal collecting agent is not limited to one having only one kind of functional group, and may be a compound having two or more kinds of different functional groups.

On the other hand, examples of the surfactant used in combination with the above-mentioned metal collecting agent include anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants and the like. Alternatively, two or more kinds can be used as a mixture. Further, surfactants having different ionic properties can be used in combination.

Examples of the anionic surfactant include salts of fatty acids such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid and oleic acid; alkyl (or alkenyl) sulfates; Alkenyl) sulfate, alkyl (or alkenyl) benzene sulfate, polyoxyalkylene alkyl (or alkenyl) ether sulfate, polyoxyalkylene alkyl (or alkenyl) ether phosphate, polyoxyalkylene alkyl (or alkenyl) phenyl ether Sulfate, α-olefin sulfate, castor oil sulfate, sodium dialkyl (or dialkenyl) sulfosuccinate and the like. As the salt, a sodium salt, a potassium salt,
Examples thereof include ammonium salts and alkanolamine salts.

The above-mentioned alkyl (or alkenyl) sulfate, alkyl (or alkenyl) benzene sulfate, polyoxyalkylene alkyl (or alkenyl) ether sulfate, polyoxyalkylene alkyl (or alkenyl) ether phosphate, polyoxyalkylene Examples of the alkyl group or alkenyl group in alkylene alkyl (or alkenyl) phenyl ether sulfate, α-olefin sulfate, sodium dialkyl (or dialkenyl) sulfosuccinate, and the like include C8 to C2.
Two, especially 12-18 are preferred. As the polyoxyalkylene group, a polyoxyethylene group,
Examples include a polyoxypropylene group and a polyoxyethylene-polyoxypropylene group (block or random copolymerization).

Examples of the cationic surfactant include alkyl (or alkenyl) dimethylamine oxide. As the alkyl group or alkenyl group of the alkyl (or alkenyl) dimethylamine oxide, those having 8 to 18 carbon atoms, particularly those having 12 to 16 carbon atoms are preferable.

Examples of the nonionic surfactant include polyoxyalkylene alkyl (or alkenyl) ether and polyoxyalkylene alkyl (or alkenyl).
Phenyl ether, polyoxyalkylene alkyl (or alkenyl) ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkyl (or alkenyl) amine, polyoxyethylene-polyoxypropylene copolymer (block or random copolymer), poly Oxyalkylene castor oil ether, polyoxyalkylene hardened castor oil ether, polyoxyalkylene alkyl (or alkenyl) ester alkoxylate, fatty acid alkanolamide and the like.
Examples of the alkyl group and alkenyl group in the compounds exemplified as the nonionic surfactant include those having 8 to 22 carbon atoms.
, Especially those having 12 to 18 carbon atoms are preferred. Also, polyoxyalkylene sorbitan fatty acid ester,
As fatty acids in fatty acid alkanolamides and the like,
Saturated or unsaturated fatty acids having 8 to 22 carbon atoms, particularly those having 12 to 18 carbon atoms are preferred. Examples of the polyoxyalkylene group include a polyoxyethylene group, a polyoxypropylene group, and a polyoxyethylene-polyoxypropylene group (block or random copolymer).

Examples of the amphoteric surfactant include alkyl (or alkenyl) betaine, alkyl (or alkenyl) dimethylaminoacetic acid betaine, alkyl (or alkenyl) amidopropyl betaine, 2-alkyl (or alkenyl) -N-carboxymethyl-N -Hydroxyethyl imidazolinium betaine, alkaloylmethyl-β
-Alanine and the like. As the alkyl group and alkenyl group of the compounds exemplified as the amphoteric surfactant,
Those having 8 to 22 carbon atoms, particularly those having 12 to 18 carbon atoms are preferred.

Among the above-mentioned surfactants, fatty acid salts of anionic surfactants, sulfated castor oil salts, polyoxyalkylene alkyl (or alkenyl) ethers of nonionic surfactants, and polyoxyalkylene alkyl (or alkenyl) esters However, it is preferable in terms of good biodegradability.

In the solid waste treating agent of the present invention, it is preferable to use the metal collecting agent and the surfactant in a ratio of 1:99 to 99: 1. The solid waste treating agent of the present invention may be provided in a form in which a metal collecting agent and a surfactant are mixed in advance, or may be provided in a form in which the metal collecting agent and the surfactant are separated. it can.

The solid waste to be treated by the method of the present invention includes, for example, incinerated ash, dust, slag, sludge, soil, shredder dust and the like generated in a garbage incineration plant.

In order to treat the solid waste with the solid waste treating agent of the present invention, for example, the treating agent of the present invention is added to the solid waste, kneaded if necessary, and mixed with a metal collecting agent. After the metal is immobilized, a method of washing and removing organic substances such as dioxins and oil in the solid waste is employed. In the method of the present invention, by adding a mixture of a metal collecting agent and a surfactant, the permeation of the metal collecting agent into the solid waste can be reduced as compared with the case where only the metal collecting agent is added to the solid waste. And the ability to immobilize the metal by the metal scavenger is also improved. According to the method of the present invention, the metal in the solid waste is securely immobilized by the metal collecting agent by adding the metal collecting agent to the solid waste and then leaving it for about 10 minutes to 2 hours. You. Washing of the solid waste on which the metal is immobilized is performed by adding water to the solid waste, stirring and mixing. Normally, water is added to the solid waste in an amount of 1 to 10 times (weight ratio), and stirring or mixing is performed for 10 minutes to
Perform for 2 hours. Since the surfactant is added to the solid waste, organic substances such as dioxins and oils contained in the solid waste are reliably eluted from the solid waste by washing. Organic substances such as dioxins eluted in the washing solution can be reliably decomposed by a standard method. Organic substances such as oil eluted in the washing solution can be treated by oxidative decomposition or biodegradation.

In the solid waste treated by the method of the present invention, the metal is securely fixed in the solid waste, and organic substances such as dioxins and oils are washed and removed. After further hardening with cement etc.
Final disposal such as burial and ocean dumping can be done safely.

[0030]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. The metal scavenger and surfactant used in the following Examples and Comparative Examples are as follows.

Metal collecting agent Metal collecting agent a: potassium diethylthiocarbamate. Metal scavenger b: a compound in which diethylenetriamine has a sodium dithiocarbamate group as a functional group. Metal collecting agent c: a compound in which a sodium dithiocarbamate group and a sodium iminopropionate group are formed as functional groups in polyethyleneimine (the ratio of sodium dithiocarbamate group to sodium iminopropionate group is 1: 1). Metal collecting agent d: a compound in which a sodium dithiocarbamate group is formed as a functional group on tetraethylenepentamine. Metal collecting agent e: potassium diethylthiocarbamate 20
A mixture of 80 parts by weight of a compound obtained by forming a sodium dithiocarbamate group and a potassium aminophosphate group as functional groups on polyethyleneimine (the ratio of sodium dithiocarbamate group to potassium aminophosphate group is 4: 1).

Surfactant Surfactant a: Sodium oleate Surfactant b: Lauryl dimethylamine oxide Surfactant c: Polyoxyethylene (9 mol) lauryl ether Surfactant d: Laurylamide propyl betaine Surfactant e : A mixture of potassium laurate: polyoxyethylene (9 mol) lauryl ether = 50:50 (weight ratio)

Using the above metal collectors and surfactants, Table 1
Were prepared.

[0034]

[Table 1]

Examples 1 to 5, Comparative Examples 1 to 5 Per kg of dust containing 643 mg / kg of lead, 52 mg / kg of cadmium, 746 mg / kg of zinc, 124 mg / kg of mercury, and 10.2 ng-TEQ / g of dioxins. Then, 50 g of the treating agent shown in Table 2 was added, kneaded and allowed to stand for 1 hour, and then 4 kg of water was added, followed by stirring for 1 hour to wash. Table 2 shows the results of measuring the concentration of dioxins remaining in the dust after cleaning. In addition, a metal elution test from the treated dust was performed according to the Environment Agency Notification No. 13 Test Method. The results of measuring the concentration of the eluted metal by atomic absorption spectrometry are shown in Table 2. The concentration of residual dioxins in the dust was determined by gas chromatography / mass spectrometry (G
C / MS method).

[0036]

[Table 2]

Examples 6 to 10, Comparative Examples 6 to 10 Mercury 13 mg / kg, lead 40 mg / kg, nickel 16
mg / kg, 38 mg / kg of cadmium, 1.1 ng-TEQ / g of dioxins, and 1.0 kg of soil containing 67 mg / kg of oil, 20 g of the treating agent shown in Table 3 was added, kneaded, and allowed to stand for 30 minutes. , Add 2 kg of water, 2
Stir for hours to wash. Table 3 shows the results of measuring the concentration of dioxins and the amount of oil remaining in the soil after washing.
In addition, the dissolution test of the metal from the treated dust was performed in Examples 1 to 5.
The measurement was performed in the same manner as described above. The amount of oil was measured by the n-hexane extraction method. The results are shown in Table 3.

[0038]

[Table 3]

[0039]

As described above, the solid waste treating agent of the present invention contains a metal collecting agent and a surfactant, whereby the permeability of the metal collecting agent to the solid waste is improved. At the same time, the metal immobilization ability is improved. Therefore, according to the method for treating solid waste of the present invention, the metal in the solid waste can be reliably fixed by the metal collecting agent, and the metal can be prevented from being re-eluted from the solid waste. Further, according to the method of the present invention, organic chlorinated substances such as harmful dioxins and organic substances such as oil are reliably washed and removed from solid waste, so that organic substances remaining in solid waste are solid. There is no danger of environmental pollution due to elution from waste. Furthermore, in the method of the present invention, organic chlorinated substances such as dioxins may be washed and eluted from solid waste and then treated, which is more reliable than the method of decomposing in solid waste. The solid waste can be easily and reliably detoxified without the risk of large amounts of undecomposed dioxins remaining in the solid waste.

Continued on the front page (72) Inventor Masafumi Moriya 4-66-1, Horikiri, Katsushika-ku, Tokyo Miyoshi Oil & Fat Co., Ltd. F-term (reference) 4D004 AA02 AA28 AA36 AA41 AA43 AB02 AB03 AB07 CA15 CA40 CA45 CC03 CC05 CC06

Claims (2)

[Claims] 1. A solid waste treating agent comprising a mixture of a metal collecting agent and a surfactant. 2. A mixture of a metal collecting agent and a surfactant is added to the solid waste to fix the metal in the solid waste with the metal collecting agent and to remove the organic matter in the solid waste. A method for treating solid waste, comprising washing and removing the solid waste.