JPH081129A - Treatment agent and method for making harmless incineration fly ash containing polyvalent metal - Google Patents

Abstract

PURPOSE:To obtain the soap-free polymerization of a resin emulsion which is free from a secondary pollution generated when a dumped sludge after treatment is remelted, and removes polyvalent metals contained in incineration fly ash at high efficiency by simple operation. CONSTITUTION:Incineration fly ash containing polyvalent metals is made harmless by a treatment agent which is composed of a resin emulsion obtained by performing a radical polymerization of a water-soluble vinyl monomer and a water-insoluble vinyl monomer, with a salt formable or a complex formable functional group, in a water solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detoxifying agent and a treating method for incineration fly ash containing polyvalent metal.

[0002]

2. Description of the Related Art Conventionally, as a chemical agent added to remove or fix polyvalent metal in incineration fly ash containing polyvalent metal such as incineration fly ash to render it harmless, a dithiocarbamic acid group is bonded to polyethylene. And water-soluble polymer chelating agents such as polyethyleneamine derivatives are known (for example, Japanese Patent Publication No. 6-2276, JP-A-3-231).
921).

[0003]

However, in the method of adding a water-soluble polymer chelating agent, there is a problem in the balance for making it insoluble in water after chelate formation. To solve this problem, expensive compounds such as polyethyleneamine are used. In addition, since the chelating substance itself is water-soluble, environmental problems such as elution of the chelating substance itself become a problem.

[0004]

Means for Solving the Problems The present inventors are a treating agent for removing or immobilizing polyvalent metal in polyvalent metal-containing incinerated fly ash such as incinerated fly ash to render it harmless, and to dispose of it. The present invention has been accomplished as a result of earnest studies to obtain a treatment agent which is free from the risk of secondary pollution due to re-dissolution of the sludge and has a fast reactivity.

That is, according to the present invention, the water-soluble vinyl-based monomer (a) and the water-insoluble vinyl-based monomer (b) having a salt-forming or complex-forming functional group are substantially used without using an emulsifying agent for emulsion polymerization. A detoxifying treatment agent for incinerated fly ash containing polyvalent metal, which is composed of a resin emulsion obtained by polymerizing a radical polymerization initiator (c) in an aqueous solvent [hereinafter, referred to as a treatment agent (1)]. And a water-insoluble vinyl monomer (b) and optionally a water-soluble vinyl monomer (a) having a salt-forming or complex-forming functional group, a water-soluble polymer having a salt-forming or complex-forming functional group. In the presence of (d), a polyvalent metal-containing incineration fly ash consisting of a resin emulsion obtained by polymerizing in a water-based solvent using a radical polymerization initiator (c) substantially without using an emulsifier for emulsion polymerization It is a detoxifying treatment agent [hereinafter referred to as treatment agent (2)].

In each of the treating agents (1) and (2) of the present invention, the salt-forming or complex-forming functional group in the water-soluble vinyl monomer (a) is, for example, a carboxyl group, a sulfonic acid group or a sulfuric acid group. Group, aminocarboxylic acid group,
Iminodicarboxylic acid group, xanthogenic acid group, phosphoric acid group,
Examples thereof include thiocarbamic acid group, dithiocarbamic acid group, thiol group, amino group, imino group, phosphomethylamino group, thioureido group, amidooxime group and acid hydrazide group. Among these, a carboxyl group, a sulfonic acid group, a sulfuric acid group, an aminocarboxylic acid group, an iminodicarboxylic acid group, a xanthogenic acid group, a phosphoric acid group, a thiocarbamic acid group and a dithiocarbamic acid group are salts of alkali metals, ammonium and the like. It may be.

Specific examples of preferable water-soluble vinyl monomers (a) having the above-mentioned functional groups include (meth) acrylic acid, styrenesulfonic acid, vinylsulfonic acid and 2-acrylamido-2-methylpropanesulfone. One or more selected from acids, vinylamine, allylamine, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and alkali metal salts or ammonium salts of these.

In the treatment agent (2) of the present invention, the salt-forming or complex-forming functional group in the water-soluble polymer (d) is exemplified as the salt-forming or complex-forming functional group in the above (a). The same thing as what was done is mentioned. Specific examples of preferable water-soluble polymers (d) having this functional group include (meth)
Acrylic acid, styrene sulfonic acid, vinyl sulfonic acid,
2-acrylamido-2-methylpropanesulfonic acid,
Examples thereof include vinylamine, allylamine, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and polymers having one or more selected from alkali metal salts or ammonium salts thereof as a constituent unit, and polyethyleneimine.

In each of the treating agents (1) and (2) of the present invention, the water-insoluble vinyl monomer (b) is 25 ° C.
A vinyl-based monomer having a solubility in water of 10 g / dl or less can be used. Examples of this include, for example, olefins such as ethylene and propylene, aromatic olefins such as styrene, vinyl esters such as vinyl acetate, dienes such as butadiene and isoprene, vinyl halides such as vinyl chloride, methyl acrylate and acrylic acid. Examples thereof include (meth) acrylic acid esters such as ethyl, methyl methacrylate, and butyl acrylate, and other vinyl-based monomers such as acrylonitrile and maleimide.

Further, a crosslinkable monomer having two or more double bonds can be used as (b). Examples of these include ethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, divinylbenzene, methylenebisacrylamide, trimethylolpropane tri (meth) acrylate, tetraallylethane and the like. Two or more of the above examples (b) may be used in combination.

In the treatment agent (1) of the present invention, the weight ratio (a) / (b) of the units (a) and (b) constituting the resin component of the resin emulsion is usually 1/99 to 90/10. ,
It is preferably 10/90 to 80/20. Further, in the treating agent (2) of the invention, among the constituent components of the resin component of the resin emulsion, the total of the units (a) and (d) and (b)
The unit weight ratio [(a) + (d)] / (b) is usually 1
/ 99 to 90/10, preferably 10/90 to 80 /
Twenty. Further, of these, (a) is a component used as necessary.

When producing the treating agent (1) of the present invention, the total weight of (a) and (b) in the polymerization system when polymerizing in an aqueous solvent is usually 1 to 70% by weight, preferably It is 10 to 60% by weight. Further, the treating agent of the present invention (2)
The total weight of (a), (b) and (d) in the polymerization system when polymerizing in an aqueous solvent for producing is usually 1 to 70% by weight, preferably 10 to 60% by weight. .

In each of the treating agents (1) and (2) of the present invention, the radical polymerization initiator (c) is not particularly limited, and specific examples thereof include azobisisobutyronitrile and azobisamidinopropane. Azo compounds such as hydrochloride and azobis cyanovaleric acid (salt); and organic peroxides such as benzoyl peroxide and ditertiary butyl peroxide, inorganic peroxides such as potassium persulfate, sodium persulfate and ammonium persulfate (It may be used as a redox initiator in which these inorganic peroxides and a reducing substance such as sodium sulfite, dimethylaminoethanol, dimethylaminobenzoic acid, etc. are combined). Among these, preferred are azobisamidinopropane hydrochloride and azobiscyanovaleric acid (salt), and water-soluble radical polymerization initiators such as potassium persulfate, sodium persulfate and ammonium persulfate. The addition amount of (c) is usually 0.001 to 1% by weight with respect to the vinyl-based monomer component to be added.

In each of the treating agents (1) and (2) of the present invention, the aqueous solvent may be water (distilled water, ion-exchanged water, tap water, industrial water, etc.) alone, or a water-soluble organic solvent in water ( Alcohols, acetone, etc.) may be included.

In each of the treating agents (1) and (2) of the present invention, other additives may optionally be present when the resin emulsion is polymerized. Other additives include, for example, a surfactant for assisting emulsification, a chain transfer agent for adjusting the molecular weight of the resulting polymer, and the like. Further, the treatment agent (1) of the present invention,
(2) In addition to the resin emulsion, each may further contain other additives if necessary. Examples of other additives include stabilizers and thickeners for stabilizing the resin emulsion, preservatives for preventing spoilage, and the like.

In each of the treating agents (1) and (2) of the present invention, the size of the micelle particles of the resin emulsion is usually
0.01 micron to 300 micron, with a preferred range of 0.05 micron to 100 micron.
If the particle size is smaller than 0.01 micron, it takes a long time to agglomerate the particles after the reaction with the polyvalent metal during use. On the other hand, when it exceeds 300 microns, the emulsion or dispersion stability in water is poor, and the adsorption efficiency of polyvalent metals and the like is poor.

The treating agents (1) and (2) of the present invention are both
It consists of a resin emulsion obtained by soap-free emulsion polymerization, substantially without using an emulsifier for emulsion polymerization. In this soap-free emulsion polymerization method, by balancing the water-soluble portion and the water-insoluble portion of the resulting polymer, the polymer becomes fine particles in an aqueous solvent, resulting in an emulsion or suspension of an aqueous resin, There is an advantage that a stable emulsion can be obtained without poisoning the active particle surface with an emulsifier.

When a resin emulsion is produced using each of the treating agents (1) and (2) of the present invention, any polymerization method such as batch polymerization method, continuous tube polymerization method and semi-continuous polymerization method is used. Good. In the case of the batch-type polymerization method, the solvent component, the vinyl-based monomer component and the radical polymerization initiator may be charged all at once to perform the polymerization, or the vinyl-based monomer component and the radical polymerization initiator may be added dropwise to perform the polymerization. Absent. The polymerization temperature and time are determined by the polymerizability of the monomer and the decomposition temperature and time of the initiator, and the temperature is usually 30 to 130 ° C, preferably 50 ° C to 100 ° C.
Further, the time is from several hours to a dozen hours. The stirring condition is an important factor in carrying out the polymerization. If the stirring is insufficient, an emulsion cannot be obtained, and a gel-like product is produced or a large amount of residual monomer remains. The particle size and particle size distribution of the polymer particles in the obtained emulsion can be controlled by the stirring speed.

The polyvalent metal-containing incineration fly ash which is the target of each of the treating agents (1) and (2) of the present invention includes heavy metals such as copper, chromium, lead, cadmium, mercury and iron, calcium, magnesium and aluminum. It is an incineration fly ash containing other polyvalent metals such as.

An example of the treatment method of the present invention using the treatment agent (1) or (2) of the present invention will be described, including the action mechanism.
The treating agent (1) or (2) of the present invention and water are added to incineration fly ash containing a polyvalent metal and the mixture is kneaded. With the addition, a bond between the functional group on the emulsion particle surface and the metal occurs, and this bond also extends between particles, and the bond reduces the zeta potential on the particle surface, causing the emulsion particles to aggregate and become water-insoluble and fixed. .

If necessary, an ordinary flocculant or neutralizing agent may be used in combination for flocculation. As the aggregating agent, an inorganic aggregating agent and / or an organic aggregating agent is used. As the inorganic coagulant, a sulfuric acid band, polyaluminum chloride, iron chloride, iron sulfate, slaked lime or the like is used. As the organic coagulant, a polyacrylamide-based polymer coagulant is usually used.

The polymer flocculant is an acrylamide polymer,
Acrylamide / acrylic acid (salt) copolymer, acrylamide / acrylic acid (salt) / 2-acrylamide-2-
Methylpropanesulfonic acid (salt) copolymer, acrylamide / (meth) acryloyloxyethyltrimethylammonium chloride copolymer acrylamide / (meth) acryloyloxyethyltrimethylammonium chloride copolymer and (meth) acryloyloxyethyltrimethylammonium chloride copolymer Nonionic, anionic, weakly cationic polymers such as coalesces are used.

[0023]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Production Example 1 Heating / cooling / stirring is possible and nitrogen aeration is possible. A reaction vessel was charged with 300 parts of water, 30 parts of acrylic acid, and 30 parts of styrene, and stirred at 300 rpm. Acrylic acid dissolved in water and styrene became suspended. Next, 0.12 parts of azobisamidinopropane hydrochloride was charged, and polymerization was carried out at 70 ° C. for 4 hours under a nitrogen stream while stirring. Along with the polymerization, the polymerization system gradually became cloudy and became an emulsified state. After the completion of the polymerization, a uniform emulsion was obtained and the reaction rate was 99%. The pH of this emulsion was 2.2, and the emulsion was neutralized to pH 8 with an aqueous sodium hydroxide solution.

Production Example 2 300 parts of water, 45 parts of dimethylaminopropylacrylamide and 30 parts of styrene were charged into the same reactor as in Production Example 1 and stirred at 300 rpm. Dimethylaminopropyl acrylamide dissolved in water and styrene became suspended. Next, add 0.1% of sodium azobiscyanovalerate.
Polymerization was carried out at 70 ° C. for 4 hours under a nitrogen stream while charging 2 parts of the mixture and stirring. Along with the polymerization, the polymerization system gradually became cloudy and became an emulsified state. After the completion of the polymerization, a uniform emulsion was obtained and the reaction rate was 99%.

Production Example 3 The same reactor as in Production Example 1 was charged with 300 parts of water, 15 parts of polyethyleneimine (molecular weight of about 70,000) and 30 parts of styrene, and stirred at 300 rpm. Polyethyleneimine was dissolved in water and styrene became suspended. Next, 0.12 parts of sodium azobiscyanovalerate was charged, and polymerization was carried out at 70 ° C. for 4 hours under a nitrogen stream while stirring. Along with the polymerization, the polymerization system gradually became cloudy and became an emulsified state. After the completion of the polymerization, a uniform emulsion was obtained and the reaction rate was 99%.

Examples 1 to 3 To 50 parts of fly ash generated by incineration of dust, 0.25 parts of the resin emulsion synthesized in Production Examples 1 to 3 and 10 parts of water were added and kneaded at 80 ° C. for 10 minutes. Dissolution test (Environmental Agency notification No. 13) was conducted on treated ash and untreated ash after kneading,
When the concentration of eluted copper ions was measured, the results shown in Table 1 below were obtained.

Comparative Example 1 Fly ash 50 produced by incineration of waste used in Examples 1 to 3
To the part, 0.17 part of a commercially available chelating treatment agent (heavy metal fixing agent manufactured by Miyoshi Yushi Co., Ltd., trade name "Epofloc L-1") and 10 parts of water were added, and the mixture was kneaded at 80 ° C for 10 minutes. The treated ash after kneading and the untreated ash were subjected to an elution test (Public Notice No. 13 of the Environment Agency), and the concentration of eluted copper ions was measured. The results are shown in Table 1 below.

[0028]

[Table 1]

[0029]

INDUSTRIAL APPLICABILITY By using the treating agent of the present invention, the polyvalent metal in the polyvalent metal-containing incineration fly ash can be removed or immobilized more efficiently than the case where the water-soluble polymer chelating agent is used, and thus harmless Be converted. Also, there is no concern about secondary pollution due to redissolution of sludge when it is discarded. When a water-soluble chelating agent is used, the effect of the elution of the chelating agent itself on the environment becomes a problem, but since the treatment agent of the present invention is insoluble in water, there is no concern about elution of the agent itself.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsura Goda 1-11, Hitotsubashi-honmachi, Higashiyama-ku, Kyoto Sanyo Chemical Industry Co., Ltd.

Claims (7)

[Claims] 1. Radical polymerization initiation of a water-soluble vinyl-based monomer (a) having a salt-forming or complex-forming functional group and a water-insoluble vinyl-based monomer (b) without substantially using an emulsifier for emulsion polymerization. A detoxifying agent for polyvalent metal-containing incinerated fly ash, which comprises a resin emulsion obtained by polymerizing the agent (c) in an aqueous solvent. 2. A water-soluble vinyl-based monomer (b) and a water-soluble vinyl-based monomer (a) optionally having a salt-forming or complex-forming functional group are added to a water-soluble vinyl group having a salt-forming or complex-forming functional group. In the presence of a water-soluble polymer (d), a polyvalent metal-containing incineration fly made of a resin emulsion obtained by polymerizing in a water-based solvent using a radical polymerization initiator (c) substantially without using an emulsifier for emulsion polymerization. Ash detoxifying agent. 3. The salt-forming or complex-forming functional group in (a) is a carboxyl group, a sulfonic acid group, a sulfuric acid group, an aminocarboxylic acid group, an iminodicarboxylic acid group, a xanthogenic acid group, a phosphoric acid group, or thiocarbamine. The treatment agent according to claim 1 or 2, which is an acid group, a dithiocarbamic acid group, a thiol group, an amino group, an imino group, a phosphomethylamino group, a thioureido group, an amidoxime group or an acid hydrazide group. 4. (a) is (meth) acrylic acid, styrenesulfonic acid, vinylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylamine, allylamine, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl. The treatment agent according to any one of claims 1 to 3, which is at least one selected from (meth) acrylamide and alkali metal salts or ammonium salts thereof. 5. The salt-forming or complex-forming functional group in (d) is a carboxyl group, a sulfonic acid group, a sulfuric acid group, an aminocarboxylic acid group, an iminodicarboxylic acid group, a xanthogenic acid group, a phosphoric acid group, or thiocarbamine. The treatment agent according to claim 2, which is an acid group, a dithiocarbamic acid group, a thiol group, an amino group, an imino group, a phosphomethylamino group, a thioureido group, an amidoxime group or an acid hydrazide group. 6. (d) is (meth) acrylic acid, styrenesulfonic acid, vinylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylamine, allylamine, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl. The treatment agent according to claim 2 or 5, which is a polymer having one or more kinds selected from (meth) acrylamide and an alkali metal salt or ammonium salt thereof as a constituent unit, or polyethyleneimine. 7. A method for detoxifying a polyvalent metal-containing incinerated fly ash, which comprises adding the treatment agent according to any one of claims 1 to 6 and water if necessary to the polyvalent metal-containing incinerated fly ash.