JP3973252B2 - Method for detoxification of PCB waste and obtained solidified product - Google Patents

Description

【００３６】
【表２】

【００３７】
【表３】

【００３８】
さらに焼却灰系固化剤と共にセメントと固化して得た固化物についての溶出試験を行った。溶出試験の結果は、表４および表５に示すように、「Ｎ.Ｄｍｇ／ｌ」とＰＣＢを検出していない。
【００３９】
【表４】

【００４０】
【表５】

【００４１】
【発明の効果】
ＰＣＢ等の液状有機ハロゲン化物の無害化を、廃棄物を燃焼して得た燃焼灰を利用し、作業性がよくかつ比較的簡単な方法により、確実に行うことができる。[0001]
[Industrial application fields]
The present invention relates to a method for detoxifying PCB waste with sodium compound or sodium metal, and a method for treating a solidified product accompanying the same, and particularly, by replacing harmful PCB with biphenyl sodium, extracting chlorine and further hydrolyzing. The present invention relates to a PCB processing method characterized by solidifying with an incinerated ash product as biphenyl.
[0002]
[Prior art]
PCB is an organochlorine compound and is an abbreviation for poly-chlorinated biphenyl. Biphenyl is one in which one benzene ring hydrogen atom is taken out and two benzene rings are combined. Biphenyl is a hydrocarbon containing no chlorine and can be used as a fuel. By replacing chlorine with hydrogen in this biphenyl, a harmful chlorine compound is produced, and various properties are exhibited depending on the number and position of chlorine.
[0003]
Conventionally, PCBs are managed and stored by the government as hazardous substances that are prohibited from moving. Recently, a method of oxidative pyrolysis at a high temperature of 1800 ° C has been proposed. However, PCB is resistant to heat, and if it is inadvertently decomposed at low temperatures, more harmful dioxins are generated and more environmental damage is caused. As is known from waking up, no safe disposal method has been found to date.
[0004]
Japanese Examined Patent Publication No. 64-8242 discloses a method for burning liquid PCB. The method described therein comprises preliminarily preparing a liquid PCB from the liquid PCB, calcium hydroxide and / or magnesium hydroxide, a water-soluble polymer, an organic acid metal salt, a silicate, and an extender. The solid composition is heated to a high temperature in the presence or absence of oxygen, and the vaporized PCB released from the solid composition is burned with oxygen. A characteristic is a liquid PCB combustion treatment method.
[0005]
[Problems to be solved by the invention]
The problem with thermally decomposed PCBs is that the chlorine atoms contained in the PCB are decomposed into gases as harmful chlorine compounds by the oxidizing action and are air polluted. Thus, discharging the gas containing harmful components into the atmosphere has an adverse effect on the environment. Therefore, harmful chlorine compounds must be made harmless inorganic chlorine compounds, treated after which no harmful substances are eluted, and discarded.
[0006]
The present invention is directed to a method of decomposing PCB into an inorganic chlorine compound, stabilizing the incinerated ash with a harmful metal stabilizer, and solidifying it in that state, and a solidified product obtained thereby. An object of the present invention is to make a liquid organic halide such as PCB harmless by using a combustion ash obtained by burning waste and ensuring a detoxification by a method with good workability and a relatively simple method. It is to provide a way to do.
[0007]
[Means for Solving the Problems]
The present invention is a method for detoxifying PCB waste, wherein the PCB waste in PCB is decomposed into biphenyl sodium and sodium chloride by alkali treatment with a catalyst and a solvent. The decomposition process for the PCB is an alkali treatment of the PCB together with a catalyst and a solvent. By the decomposition treatment for PCB, PCB can be decomposed into biphenyl sodium and sodium chloride, and biphenyl sodium can be further hydrolyzed into biphenyl.
[0008]
Accordingly, the present invention is a PCB waste characterized by decomposing biphenyl sodium and sodium chloride into biphenyl by hydrolyzing biphenyl sodium and sodium chloride by treating the PCB in the PCB waste with an alkali together with a catalyst and a solvent. This is a detoxification treatment method.
[0009]
In the present invention, as the catalyst, metals contained in cobalt chloride, ferrous chloride, aluminum chloride, ethylenediamine, wood vinegar and / or incinerated ash are used. Methanol and / or diethyl ether is used as the solvent.
[0010]
In the present invention, the alkali treatment is treatment with an aqueous solution of complex metal ions of potassium, calcium, aluminum, magnesium, boron and / or fluorine in addition to sodium.
[0011]
In the present invention, an organic chlorine compound such as PCB is dissolved in diethyl ether and methanol, stirred with an aqueous ionic solution such as orthosilicate, calcium oxide, and anhydrous sodium carbonate, added with cobalt chloride and wood vinegar as a catalyst, and stirred. Mix with sodium oxide and stir. By mixing sodium hydroxide, the emulsion solution becomes radicals, where the metals contained in the incineration ash are catalyzed, separated into inorganic chlorine compounds and biphenyl, and mixed with ammonium chloride to stir the ammonia bond. Unused electron pairs are shared with the (hydrogen chloride) acid in the aqueous solution to form NH ₄ ⁺ ions that combine with chloride ions to form a salt called ammonium chloride. Thereby, a stable solidified product by a stabilizing solidifying agent by the incinerated ash soil conditioner is generated.
[0012]
That is, the PCB stabilization method of the present invention decomposes an organic chlorine compound produced by substitution of a hydrogen atom and a chlorine atom of a benzene ring into a biphenyl compound and a chlorination compound by a substitution action of metal sodium, and further, if necessary, biphenyl. Biphenyl caustic soda is obtained by hydrolyzing sodium. Aromatic hydrocarbons such as benzene are electrical insulators and do not conduct electricity. This is because there are no ions in the covalently bonded compound, so it does not show electrical conductivity, so water hydronium ions and hydroxide ions are generated, without creating an electric pair between the hydrocarbon atoms. By creating a single charged electron, the electron carries electricity in the form of a relay, and electricity is conducted. This means that ions are generated and the substitution reaction of sodium ions proceeds. In addition, in covalently bonded compounds, the molecules bind molecular forces to each other, and the electric attractive force is not working, and the molecular force is relatively weak. do not do. Therefore, the reaction takes place without high energy such as high temperature and pressure.
[0013]
What decomposed | disassembled with respect to PCB in the said PCB waste can be solidified with an incineration ash type solidification agent. The present invention is a detoxification method for PCB waste, characterized in that the PCB in PCB waste is decomposed and solidified by an incinerated ash-based solidifying agent.
[0014]
The incinerated ash-based solidifying agent used in the present invention is obtained by heat-treating incinerated ash with a rotary kiln, and then converting the incinerated ash into a fine powder, for example, a fine powder of 100 mesh or less. When heat treating the incinerated ash with a rotary kiln, it is preferable to add Portland cement. Portland cement can be further added to the fine powder. Furthermore, it can also heat-process with another rotary kiln.
[0015]
The incinerated ash-based solidifying agent is a cement obtained by subjecting combustion ash containing harmful heavy metals remaining after incineration of general waste, sewage sludge, sludge and / or industrial waste to cement. Cementation of incineration ash is performed by adding a heavy metal insolubilizer as an adjusting agent to the incineration ash, for example, and heat-treating it with a rotary kiln, and then using a pulverizer to make fine powder of 100 mesh or less. When heat-treating with a rotary kiln, potassium sulfate and sodium sulfate can be added to the incinerated ash as heavy metal insolubilizers, and a small amount of Portland cement can be mixed to produce a raw material for cement-based special solidifying agents. In this way, incinerated ash containing harmful heavy metals can be reused.
[0016]
The heavy metal insolubilizing agent is composed of, for example, a combination of potassium sulfate, sodium sulfate and Portland cement. These are used at a ratio of potassium sulfate 1, sodium sulfate 1 and Portland cement 2 to incineration ash 100 by weight. Portland cement is mainly required for the hydration reaction, but also contributes to insolubilization of heavy metals. Thermal circulation is performed in a rotary kiln, and the surface side of the incinerated ash is enlarged by making it a fine powder of 100 mesh or less with a pulverizer, and the surface energy of the contained heavy metals is also increased.
[0017]
Incineration ash that will contain unburned carbon, hydrocarbons, etc. in the heat treatment in the rotary kiln is dechlorinated and hydrogenated by heat treatment in a low-oxygen atmosphere, and pulverized into fine powder This increases the surface area. Among the heavy metals contained in incineration ash, there are elements suitable for catalysis of chemical reactions, and it is also possible to play a role as a reaction accelerator.
[0018]
The harmful heavy metal stabilizer, which is a basic blending component of the cement-based special solidifying agent of the present invention, is potassium sulfate (K ₂ SO ₄ ), potassium chloride (KCl), sodium sulfate (Na ₂ SO ₄ ), sodium silicate ( Na ₂ SiO ₃ · nH ₂ O), sodium sulfide (Na ₂ S · 5H ₂ 0), calcium chloride (CaCl ₂ ), calcium carbonate (CaCO ₃ ), sodium hydroxide (Ca (OH) ₂ ), gypsum (Na ₂ SO ₄ 2H ₂ O), ammonium chloride (NH ₄ Cl), iron sulfide (FeS ₂ ) and the like are exemplified, and potassium sulfate and sodium sulfate are the most preferred examples.
[0019]
That is, in the present invention, a harmful heavy metal stabilizing agent containing at least potassium sulfate and sodium sulfate is used. That is, incinerated ash is heat-circulated in a rotary kiln, and a harmful heavy metal stabilizer, preferably potassium sulfate and / or sodium sulfate, is added to a fine powder of 100 mesh or less by a pulverizer, and Portland cement is further added. A cement-type special solidifying agent mixed in a small amount is completed.
[0020]
Further, as a harmful heavy metal stabilizer, potassium chloride, sodium silicate, sodium sulfide, calcium chloride, calcium carbonate, sodium hydroxide, gypsum, ammonium chloride and iron sulfide can be contained. These harmful heavy metal stabilizers are preferably added as an aqueous solution. By mixing these as an aqueous solution, an aqueous ionic solution is produced. Even in an ionic substance, calcium carbonate (CaCO ₃ ) having an ionic charge of 2 ⁺ and 2 ⁻ is hardly dissolved. In addition, it is difficult to melt those having strong ion-bonding power. Even a molecular substance having a large amount of hydrophilic group —OH creates hydrated ions. A complex is formed by anions gathering around metal ions, strengthening the action of rock formation by hydration reaction, and making H ₂ SiO ₂ + SiO ₂ , which is the main component of rock, over a long period of time. It enhances rockiness.
[0021]
Currently, the most important problem in the Waste Society regarding the disposal of incineration ash is lead treatment. The environmental standard value of lead goes up, and lead can hardly be cleared by the conventional treatment method. However, the hazardous heavy metal stabilizer used in the present invention has two types of products “RC2001” and “RC6001” containing the above-mentioned compounds. The pH concentration of RC6001 is 2.6 and the pH concentration of RC2001 is 12.9. is there. By adding heavy metal insolubilizing agent and harmful heavy metal stabilizer, the lead compound is combined as lead sulfide. That is, after lead is incinerated, lead oxide becomes lead chloride. The solubility of lead compounds in water is 10,700 ppm at maximum for lead chloride, 1.07 ppm for lead oxide, 0.452 ppm for lead sulfate, and 0.010 to 0.014 ppm for lead sulfide. Lead is highly reactive with sulfur, and lead oxide and lead chloride are subjected to acid extraction (RC6001), and the reaction between lead and sulfur is performed after extraction.
[0022]
The present invention also relates to a solidified product produced by any one of the above detoxification methods. In the present invention, PCBs in PCB waste are decomposed into biphenyl sodium and sodium chloride by alkali treatment with a catalyst and a solvent, and further hydrolyzed biphenyl sodium into biphenyl, and then incinerated ash is used as a modifier for heavy metals. It is a solidified product solidified by an incinerated ash-based solidifying agent obtained by adding an insolubilizing agent and heat-treating with a rotary kiln and then obtaining a fine powder of 100 mesh or less with a pulverizer. Instead of the incinerated ash-based solidifying agent, a cement-based special solidifying agent obtained by further blending Portland cement and a toxic heavy metal stabilizing agent may be used as necessary.
[0023]
Moreover, this invention is the solidification product which solidified incineration ash with the said cementitious special solidification agent. The product solidified by using the solidifying agent for incineration ash of the present invention forms a cementitious material as a metal compound, not as a simple metal.
[0024]
In any chemical treatment method for hazardous substances contained in incineration ash, the most important issue is the mixing and incineration efficiency of incineration ash and chemicals. , Repeated test of treatment time, the inorganic components of the incinerated ash particles are lime (CaO), silicic acid (SiO ₂ ), alumina (Al ₂ O ₃ ), iron (Fe ₂ O ₃ ) necessary for solidification, A compound such as sulfate radical (—SO ₄ ) reacts with water to form a hydrate, and the ionic charge is corrected according to the change in the liquid ion concentration, and deposition begins.
[0025]
The biggest impediment to hardening of liquid, gas and organic matter in incineration ash is that cement hydraulic minerals react quickly with calcium ions generated by hydrolysis to form insoluble or soluble compounds. is there. For example, in the case of forming an insoluble salt, the main component covers the surface of the cement particles and prevents the subsequent reaction from proceeding. It is the action that waits for. In any case, the chemical balance of the hydration reaction is lost if calcium ions, which should be the main component of the hydration reaction, are taken away by other reaction systems. Therefore, by mixing the stable calcium treating agent of the present invention, the liquid phase increases the lime content and becomes an alkaline composition, and further solidifies before reaching the hydration inhibitory effect by a rapid hydration reaction. By promoting the hydration reaction of lime aluminate hydrate and increasing the production of ettringite (3CaO.Al ₂ O ₃ .3CaSO ₄ .32H ₂ O), A salt fixes a harmful substance including a heavy metal so that it does not elute.
[0026]
By adding ammonia to the cement-based special solidifying agent according to the present invention, the hydrogen atom of the ammonia molecule having ammonia as a ligand is replaced with an organic hydrocarbon group, and nitrogen atoms are bonded to two positions of the hydrocarbon group. The molecule creates a kind of ring when the nitrogen atom is coordinated and increases stability.
[0027]
Since cement forms a solidified product due to the solidification effect of the hydration reaction of etrin guide, the solidification effect at minus temperature is impossible. However, the cement-type special solidifying agent of the present invention can be solidified at a minus temperature by reaction with ammonia molecules.
[0028]
【Example】
Examples of the present invention will be shown below, but the present invention is not limited to these examples, and the gist of the present invention can be understood by these examples.
[0029]
Reference Example Manufacture of incinerated ash-based solidifying agent Incinerated ash from Edozaki Sanitary Association, Mitaka City, Nihombashi Sanitary Association, Tokyo and Osaka City was used. A 100-mesh incinerated ash was heat-processed while stirring in a kiln at 600 ° C. for about 30 minutes to prepare a cemented product of the incinerated ash. At that time, 10 g of potassium sulfate (K ₂ SO ₄ ), 10 g of sodium sulfate (Na ₂ SO ₄ ), and 50 g of Portland cement were used as regulators.
[0030]
As a main raw material of the cement-based special solidifying agent, 1000 g of a cemented product pulverized to 100 mesh and 200 g of Portland cement are mixed well.
In order to chemically treat heavy metals contained in incineration ash, an aqueous solution of a toxic heavy metal stabilizer is prepared by using 5 g of sodium silicate (Na ₃ SiO ₃ .nH ₂ O), ₂ g of calcium carbonate (CaCO ₃ ), carbonic acid. 2 g of sodium (Na ₂ CO ₃ ), ₃ g of potassium sulfate (K ₂ SO ₄ ), ₂ g of potassium chloride (KCl), 3 g of sodium sulfate (Na ₂ SO ₄ ), ₂ g of calcium chloride (CaCl ₂ ), calcium hydroxide (Ca (Ca ( OH) ₂ ) 5 g, gypsum (Ca (OH) ₂ 2H ₃ O) 3 g, ammonium chloride (NH ₄ Cl) 5 g and iron sulfide (FeS 2) 10 g were mixed with 10 liters of water and prepared.
[0031]
100g powder of incineration ash from the garbage incineration plant is mixed with 1000g, 200g of Portland cement and 300g of the main raw material of the above cement-based special solidifying agent, and 10 The elution test was carried out with a 4-week curing period after the mixture was diluted twice, kneaded with a slump of 8 cm in water content, and solidified.
[0032]
The dissolution test was conducted for cadmium, cyan, organophosphorus, lead, hexavalent chromium, arsenic, and alkylmercury. As a result of this test, cyan, organophosphorus, hexavalent chromium and alkyl mercury were not detected, lead was less than 0.5 mg / l, cadmium and arsenic were less than 0.05 mg / l, and total mercury was 0.0005 mg / l. Both were less than the criteria for toxic substances.
[0033]
Example 1
500 cc of diethyl ether and 500 cc of methanol are mixed with 4000 cc of PCB with a concentration of PCB of 9400 mg / l and stirred for 30 minutes. Next, 40 g of silicon dioxide powder, 60 g of potassium chloride, 200 g of sodium carbonate, 40 g of aluminum chloride, 40 g of potassium chloride, 200 g of ammonium chloride, 40 g of sodium chloride, 20 g of cobalt chloride and 200 g of ferrous chloride are added while stirring with sodium hydroxide. Mix, heat to 110 ° C. with stirring for about 60 minutes, and add 100 cc of hydrogen fluoride little by little.
[0034]
After 24 hours, biphenyl is separated into two layers, with the solvent in the upper layer and the precipitate in the lower layer. By this solvent extraction, the PCB content of 94,000 mg / l in Table 1 decreased from 72 mg / l in Table 2 to 4.7 mg / l in Table 3.
[0035]
[Table 1]

[0036]
[Table 2]

[0037]
[Table 3]

[0038]
Furthermore, an elution test was performed on the solidified material obtained by solidifying with cement together with the incinerated ash-based solidifying agent. As a result of the dissolution test, as shown in Tables 4 and 5, “N.Dmg / l” and PCB were not detected.
[0039]
[Table 4]

[0040]
[Table 5]

[0041]
【The invention's effect】
The detoxification of liquid organic halides such as PCB can be reliably performed by using a combustion ash obtained by burning waste and having a good workability and a relatively simple method.

Claims (9)

PCBs in PCB waste are decomposed into biphenyl sodium and sodium chloride by alkali treatment with a catalyst and a solvent, and after decomposition by alkali treatment, the incinerated ash is heated in a rotary kiln after decomposition by alkali treatment. PCB disposal characterized by being solidified by an incinerated ash-based solidifying agent that has been treated and then made into a fine powder by a pulverizer, and solidifying in the presence of a hazardous heavy metal stabilizer containing potassium sulfate and / or sodium sulfate Detoxification method of things.   The method for detoxifying PCB waste according to claim 1, further comprising hydrolyzing biphenyl sodium into biphenyl.   The method for detoxifying PCB waste according to claim 1 or 2, wherein the catalyst is a metal contained in cobalt chloride, ferrous chloride, aluminum chloride, ethylenediamine, wood vinegar and / or incinerated ash.   The method for detoxifying PCB waste according to claim 1, 2 or 3, wherein the solvent is methanol and / or diethyl ether.   The method for detoxifying PCB waste according to any one of claims 1 to 4, wherein the alkali treatment is treatment with a mixed metal ion aqueous solution of potassium, calcium, aluminum, magnesium, boron and / or fluorine in addition to sodium.   The method for detoxifying PCB waste according to any one of claims 1 to 5, wherein Portland cement is added when incineration ash is heat-treated with a rotary kiln.   The method for detoxifying PCB waste according to any one of claims 1 to 6, wherein Portland cement is further added after making the powder fine. The incinerated ash-based solidifying agent is obtained by detoxifying PCB waste according to any one of claims 1 to 7 , wherein the incinerated ash is heat-treated with a rotary kiln, then finely ground with a pulverizer, and further heat-treated with a rotary kiln. Processing method.   A solidified product produced by the detoxification method according to any one of claims 1 to 8.