JP2001233621A - Method of vitrifying treatment with treated ash and molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that when treated ash remained after the incineration treatment of wastes and having toxic materials of halogen-containing substance (especially chlorine-containing substance) is used as a resource through melting and vitrification, there is a danger of deposition of toxic materials during the heat treatment when the treated ash is molten and vitrified. SOLUTION: The treated ash having halogen-containing substances and a treating agent for dechlorination which contains glass components, are charged into a heat treatment furnace 1, and they are heat-treated. This can perform simultaneously dechlorination and vitrification to obtain glass products.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of adding a dechlorinating agent containing a glass component to ash containing a glass component and heating the ash to decompose and precipitate a halogen-based substance contained in the ash. In addition to detoxifying the decomposed gas and treated ash by producing a harmless chloride by contact reaction with the treating agent, a vitrification method and a glass molded product obtained by melting and molding the same, particularly And technology for vitrifying ash for effective use.

[0002]

2. Description of the Related Art Incineration ash generated in the incineration of various wastes, fly ash supplemented by various dust collectors carried with exhaust gas, sludge incineration ash obtained by dehydration and incineration of various sludges, dry sludge, There is a huge amount of detoxified objects such as contaminated soil.

[0003] These ashes contain harmful halogen-based organic compounds (dioxins, hydrogen chloride, etc.), and simply disposing of them in a landfill poses a problem of environmental pollution due to elution of dioxins. Therefore, it is desired to develop a technology that can safely treat the treated ash and that can be recycled, and various treatment methods have been proposed.

For example, a method in which glass cullet powder is granulated on aluminum residual ash or the like as a binder, fired and solidified, and used as an aggregate for concrete (JP-A-11-31495)
0) or a method of converting incinerated ash into slag and obtaining a foam material that can be effectively used as a building material from pulverized slag glass (JP-A-11-171661), or re-burning incinerated ash from the viewpoint of environmental pollution prevention A method of obtaining a glass-like fired product and encapsulating heavy metals and halogenated organic substances contained in the incineration ash in vitreous so as not to elute into water (Japanese Patent Laid-Open No.
-21215).

[0005] In addition, the applicant of the present application also discloses a method of detoxifying harmful substances such as dioxins contained in treated ash such as incinerated ash, fly ash and sludge incinerated ash. JP-A-11-19616) and a processing method in which the harmless treated ash is vitrified and powdered to enable effective utilization as a construction material (JP-A-11-19616).
1145435).

[0006]

When vitrifying incinerated ash for effective use as a resource, the treated ash contains harmful halogenated organic compounds. Chlorine gas is generated, which causes dioxins. That is, harmful chlorine-based gas is generated during melting and heating in the molding process, either when obtaining the above-mentioned concrete aggregate, when obtaining a foamed material, or when encapsulating heavy metals or halogenated organic substances in glass. However, no detoxification measures have been taken.

[0007] On the other hand, the one proposed by the applicant of the present application is to mix a treated ash and a dechlorinating agent composed of an alkali substance and heat them, and to remove harmful hydrogen chloride and dechlorinating agent generated during heating. To make harmless treated ash by contacting and reacting with harmless chloride, and dissolving this harmless treated ash, solidifying it by cooling, vitrifying it, and powdering it for effective use This is an environmentally preferable treatment method for removing harmful chlorine-based gas from treated ash during heating and melting.

[0008] However, this treatment method is to vitrify the treated ash and further use this vitrified material as a powder. However, according to a subsequent investigation and research, the treatment agent used for dechlorination is originally not used. It was found that many glass composition components were contained, and it was found that the ash to be treated could be easily vitrified by this treating agent.

An object of the present invention is to provide a vitrification method using the ash to be treated and a technique for obtaining a vitrified molded product from the treated ash.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a glass composition component is contained in treated ash (incinerated ash, fly ash, sludge incinerated ash), dried sludge, and contaminated soils (hereinafter referred to as ash to be treated). Dechlorination of treated ash which is contained to some extent and which has been previously proposed by the present inventors and vitrification thereof (Japanese Unexamined Patent Publication No.
19616, JP-A-11-114535), or the use of this treating agent by focusing on the fact that the treating agent for dechlorination for purifying exhaust gas by spraying onto a bag filter also contains a large amount of glass composition components. And a method of vitrifying the ash to be treated.

(1) As a treating agent, an alkali metal, an alkali metal compound, an alkaline earth compound, an alkaline earth compound, which reacts with a harmful component decomposed and precipitated from an object to be treated by heating to form a harmless chloride The use of an alkali substance contained in the metal compound, (a) the treating agent for the alkali metal compound includes sodium hydrogen carbonate, sodium carbonate,
Sodium sesquicarbonate, natural soda, potassium carbonate, potassium bicarbonate, sodium carbonate, sodium hydroxide,
Potassium hydroxide is contained, and (b) alkaline earth metal compounds include lime (CaO), slaked lime (CaCOH ₂ ), calcium carbonate (CaCO ₃ ), dolomite (CaCO _3.
MgCO ₃ ), and (2) ash to be treated includes (a)
Alkali metals (Li, Na, K, Rb, Cs, Fr) and (b) alkaline earth metals (Ca, Sr, Ba, R
(3) On the other hand, the main component of the soda glass has a composition centered on Na ₂ O.CaO.5SiO ₂ (natural soda), and the main component range (% by weight) _{is, SiO 2: 65~75, Na 2} O: 10~20,
CaO: 5 = 15, other: Al ₂ O ₃ , MgO, Fe ₂
Focusing on the fact that it is O ₃ , that is, the alkali substance used for the detoxification treatment of the ash to be treated inherently contains a large amount of glass composition components, the amount of the treatment agent is adjusted to the glass composition (control). It was found that the ash to be treated after the treatment can be easily vitrified by the addition.

The present invention has been made based on these findings, and means for solving the above-mentioned problems include a treatment ash containing a halogen-based substance and a treatment agent comprising an alkali substance containing a glass component. Is mixed and heated in a heat treatment furnace by external heating means, and the halogen-based substance decomposed and precipitated from the ash to be treated is brought into contact with the treating agent to produce harmless chlorides, thereby rendering the harmless gas harmless. And detoxification and vitrification of the ash to be treated.

Further, the ash to be treated containing a halogen-based substance and a treating agent comprising an alkali substance containing a glass component are mixed and heated in a heating furnace by an external heating means to decompose and precipitate from the ash to be treated. The harmless chloride is generated by contacting the treated halogen-based substance with the treating agent, thereby detoxifying the decomposed gas and the ash to be treated, and at the same time, the main components of soda glass, Si, Na, Vitrification is achieved by controlling the amount of Ca added.

There are various types of ash to be treated, and the components vary widely depending on the treatment method. Therefore, the components of these ash to be treated are analyzed and investigated in advance, and the deficient Si, C
The amount of addition is adjusted (controlled) according to the amounts of a and Na.

[0015] Then, the amount of the main component of soda glass (wt%), preferably, SiO ₂ is 65 to 75, N
aO ₂ is 10-20 and CaO is 5-15 component ratio.

The treating agent for an alkaline substance used in the present invention is disclosed in Japanese Patent Application Laid-Open No.
19616, JP-A-11-114535, a treatment agent, that is, an alkali metal which reacts with a harmful substance which is decomposed and precipitated from an object to be treated by heating to form a harmless chloride,
At least one kind is selected from alkali metal compounds, alkaline earth compounds, and substances contained in alkaline earth metal compounds, or a mixture of two or more kinds is used.

The alkali metal compounds therein include sodium hydrogen carbonate, sodium carbonate, sodium sesquicarbonate,
Including simple soda selected from natural soda, potassium carbonate, potassium bicarbonate, sodium potassium carbonate, sodium hydroxide, potassium hydroxide, and a mixture of plural kinds.

Also, the above-mentioned (a) sodium hydrogen carbonate
Also known as acidic sodium carbonate, sodium bicarbonate, and sodium bicarbonate.

(B) Sodium carbonate is another name such as sodium carbonate, soda, soda ash, washing soda, and crystal soda.

(C) Sodium sesquicarbonate is another name, sodium monohydrogen dicarbonate, sodium tricarbonate, sodium sesquicarbonate. (D) Natural soda is another name, trona.

The heating temperature by the external heating means in the above-mentioned heat treatment furnace is a temperature at which the halogen-based substance is decomposed and precipitated from the ash to be treated and is 500 ° C. to 800 ° C. which is lower than the melting point of chloride.
C is desirable.

The ash to be treated to be vitrified in the present invention is:
Any of incineration ash, fly ash, sludge incineration ash, dry sludge, contaminated soil, or a mixture thereof may be used.

Further, the glass molded article according to the present invention is obtained by mixing ash to be treated containing a halogen-based substance and a treating agent comprising an alkali substance and heating the mixture in a heat treatment furnace by an external heating means. A halogen-based substance decomposed and precipitated from the material and a treating agent are contact-reacted to form harmless chlorides, thereby detoxifying the decomposed gas and detoxifying the ash to be treated, and obtaining a molten glass. Is taken out and formed into a predetermined shape (plate, block, container) or processed into a cullet, so that it can be used as a raw material of a foam material.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. The present invention relates to treated ash (incinerated ash, fly ash, sludge incinerated ash, etc.) containing glass components, dried sludge, contaminated soils, and contaminated lands (contaminated coastal sands, factories, agricultural lands, etc.) from general land and the like (hereinafter, referred to as ash) And ash to be treated), by removing halogen-based substances (chlorine, bromine, iodine, fluorine, and astatins), particularly chlorine, to render them harmless and vitrifying them. Block material, bottles, various containers, etc.) or cullet.

FIG. 1 is a conceptual diagram for explaining a method of vitrifying the ash to be treated. Reference numeral 1 denotes a heat treatment furnace. The heat treatment furnace 1 includes a rotatable rotary cylindrical body 1a,
A gas duct is formed around the outer periphery of the rotating cylinder 1a, and the rotating cylinder 1a and the rotating cylinder 1a are formed by introducing hot gas.
And a heating jacket 1b for externally heating ash to be treated as an object to be treated therein. The external heating means may be an electric heating means (induction heating, resistance heating, microwave heating).

Reference numeral 2 denotes a supply duct, which introduces a mixture obtained by mixing the ash to be treated and the treating agent for dechlorination into the rotating cylindrical body 1a of the heat treatment furnace 1. Reference numeral 3 denotes a discharge-side duct which discharges vitrified ash that has been heat-treated in the heat treatment furnace 1.

The rotary cylinder 1a is made of an iron-based metal member, and although not shown, has a feed blade therein, and has a supply port at one end connected to the supply duct 2 and a discharge port at the other end. The side communicates with the discharge side duct 3, is rotatably supported by a support roller, and is configured to be rotationally driven by rotational driving means. The mixture of the ash to be treated and the treatment agent is transferred from the supply port side to the discharge port side while being stirred by the rotation of the rotary cylindrical body 1a.

The heating jacket 1b and the supply-side and discharge-side ducts 2 and 3 are fixed, and the rotating cylindrical body 1a
A mechanical seal is applied to the rotating contact part with
Gas leakage from the rotating contact part is prevented.

Reference numeral 4 denotes a hot gas generating means for generating a hot gas by burning a fuel such as LNG, LPG or petroleum, and introducing the hot gas into the heating jacket 1b.

Reference numeral 5 denotes a decomposed gas treatment means, which has a gas combustion furnace, an exhaust gas cooling means, a purifying means such as a bag filter, etc., and introduces the decomposed gas generated during the heat treatment in the heat treatment furnace 1 and burns it. The gas after combustion is cooled, cleaned with a bag filter and discharged.

Numeral 6 denotes a glass forming means for receiving vitrified ash which has been subjected to heat treatment in the heat treatment furnace 1 and from which harmful components have been removed, and forms it. 7 is a solidifying means,
The glass molded product formed by the glass forming means 6 is gradually cooled and solidified. Numeral 8 denotes a solidified molded product collecting means for transferring and collecting the molded product 7a solidified by the solidifying means 7 by a conveyor or the like.

When the external heating means is electric heating, the heating jacket 1b and the hot gas generating means 4 are not required.

Next, a series of treatment methods for vitrifying the ash to be treated will be described. First, the hot gas generating means 4
A fuel such as NG is burned to generate a hot gas, which is introduced into the heating jacket 1b and drives the rotary cylinder 1a to rotate.

Next, a mixture obtained by sufficiently mixing the ash containing a halogen-based substance and a treating agent (for example, sodium hydrogen carbonate) through the supply duct 2 is supplied to the heating furnace 1 through the supply duct 2. Supply. As the treatment agent, a powder is usually used, but the form is of course arbitrary.

The ash to be treated has a different glass component-related content due to municipal garbage incineration ash or fly ash discharged from a waste incineration plant, but the glass component-related content in the latter fly ash. (G / Kg) is 6-3
No. 8863, Ca: 80-100, K: 30-
_{45, Na: 10~30, SiO 2} : and has a 250 to 500.

On the other hand, the components (% by weight) of soda glass
SiO ₂ as described above: 65~75, Na ₂ O: 10~2
0, CaO: 5 to 15, other: Al ₂ O ₃ , MgO, F
Since it is e ₂ O ₃ , a glass can be produced by adjusting the components mainly with Si and Na.

That is, glass-related components (g / K) of incinerated fly ash
The amount g) is, Ca is 80 to 100, K is 30-45, Na 10 to 30, for example in the case SiO ₂ is 250 to 500, from the intermediate value and a glass component ratio, the lack of the glass component Can be obtained as shown in Table 1. Then, the insufficient Si and Na from Table 1 are added, and a treating agent for an alkaline substance is added.

[0038]

[Table 1]

As for glass-related components in municipal incineration ash, as shown in JP-A-11-347515, Ca: 23.2, Si: 8.
0, K: 4.0, and Na: 3.5, respectively. (Since the exhaust gas is purified by spraying Ca with a bag filter, the Ca content tends to be large.) As described above, the glass component relationship differs depending on the ash to be treated. It is necessary to investigate and determine each type of ash.

The glass component of the ash to be treated generally lacks Na ₂ O. To compensate for this, sodium bicarbonate (Na) used as a treating agent for dechlorination was used.
HCO ₃ ), sodium carbonate (Na ₂ CO ₃ ), (also called soda ash), and sodium sesquicarbonate (also called natural soda) are added and mixed.

In the heat treatment in the heat treatment furnace 1, the temperature and time at which harmful components, especially chlorine-based gas (hydrogen chloride), are decomposed and precipitated from the ash to be treated are investigated in advance, and the ash to be treated is The properties specific to the class are grasped, and the treatment is performed at a temperature and time (500 ° C. to 800 ° C., preferably 600 ° C., about 1 hour) at which the chlorine-based gas is sufficiently precipitated based on the investigation results.

The temperature and time are determined by the condition of the heating furnace (conditions depending on the furnace such as the size and heating means), the amount of treatment,
Since it is related to the processing time, the processing temperature, and the like, it is necessary to accumulate data.

The heat treatment in the heat treatment furnace may be such that drying, dechlorination, and vitrification are performed in one heat treatment furnace 10, as shown in the schematic diagram of FIG. 2
Drying / dechlorination furnace 11 and vitrification furnace 1 as shown in FIG.
2 are disposed vertically, and the ash to be treated, which has been dechlorinated in the drying / dechlorination furnace 11, is introduced into the vitrification furnace 12 through the communication duct 13, where it is melted and vitrified. The choice is made according to the properties of the ash to be treated.

The heating furnaces 10, 11, and 12 are
A furnace having the same configuration as the heat treatment furnace 1 in FIG. 1 can be used. That is, a configuration is provided in which a rotating cylindrical body provided with rotating feed blades for carrying and stirring the processed material therein, and an external heating means are provided.

The heat treatment in the heat treatment furnace 1 shown in FIG. 1 is not "combustion and incineration" but "steaming,
In the `` pyrolysis '' treatment, the harmful chlorine-based gas decomposed and precipitated from the ash to be treated by heating is effectively reacted with a treating agent consisting of an alkaline substance, and the harmful chlorine-based gas is replaced with harmless salts. Let it.

That is, when sodium hydrogencarbonate (NaHCO ₃ ) is used as a treating agent, when hydrogen chloride (HCl) is generated in the heat treatment furnace 1, a contact reaction occurs immediately and (NaHCO ₃ ) + (HCl) → (HCl). NaCl) +
(H ₂ O) + (CO ₂ ), which is replaced and produced by harmless sodium chloride (NaCl), harmful hydrogen chloride in the decomposed gas is eliminated, and the decomposed gas is rendered harmless and treated ash after deposition of harmful components. Detoxification is performed at the same time.

By adding the treatment agent for dechlorination into the heat treatment furnace 1 as described above, harmless chlorides (NaC
l) is present, but the melting point of this chloride is 801 ° C., and the heating temperature of the heat treatment furnace by external heating means is 80 ° C.
If the temperature is set to 0 ° C. or lower, a problem such as precipitation of chlorine due to melting does not occur.

The molten glass obtained in the heat treatment furnace 1 is introduced into a glass forming means 6, where it is formed into a predetermined shape (plate, block, container, etc.) (or cullet is obtained) and solidified by a solidifying means 7. The molded product 7a is solidified while being gradually cooled, and is collected by the solidified molded product collecting means 8.

Accordingly, a glass molded article can be obtained by dissolving the detoxified ash to be treated and an alkali substance of the same component as the detoxifying treatment agent, and effectively reusing the ash to be treated. Can be. Further, the molten glass is disclosed in
It can also be used as a raw material of a foaming material like 1661.

On the other hand, the decomposition gas generated during the heat treatment in the heat treatment furnace 1 is rendered harmless by the contact reaction with the treating agent and does not contain toxic chlorine-based gases (hydrogen chloride, chlorine gas). In order to ensure safety, the decomposition gas processing means 5
, Where it is subjected to combustion treatment, and the gas after combustion is cooled (recovered by warming) and discharged through a bag filter. The heat gas after heating the heat treatment furnace 1 uses exhaust heat by a heat exchanger or the like, and then is sent to the decomposed gas processing means 5 to be burned and then discharged, so that thermal energy can be effectively used.

[0051]

As described above, the present invention relates to the treatment of ash to be treated (incinerated ash, fly ash, sludge incinerated ash, sludge dried, contaminated soils) containing glass components contaminated with halogen-based substances. The treated product and the treatment agent for dechlorination consisting of an alkali substance were mixed and heated to perform the dechlorination treatment, and the glass component contained in the treatment agent was vitrified. Has the effect of (1) Ashes to be treated, including glass components contaminated with halogen-based substances, are used to detoxify incineration ash, fly ash, sludge incineration ash, dry sludge, contaminated soil, etc. The ash to be treated is added together with the alkali substance to be added, so that the amount of components required for the formation of chloride by dechlorination and the formation of glass will be detoxified and the generated gas detoxified. Can be vitrified. (2) The harmful dioxins are not contained in the vitrified material to be processed, so that it can be effectively used for multiple purposes.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an embodiment of the present invention.

FIG. 2 is a schematic diagram of an embodiment of the present invention.

[Description of Signs] 1 ... Heat treatment furnace 1a ... Rotating cylindrical body 1b ... Heating jacket 2 ... Supply side duct 3 ... Discharge side duct 4 ... Hot gas generation means 5 ... Decomposition gas treatment means 6 ... Glass forming means 7 ... Solidification means 8 ... means for collecting solidified molded products

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C03B 1/00 B09B 3/00 304K F term (Reference) 2E191 BB01 BC01 BC02 BD01 BD11 4D004 AA36 AA37 AA41 AB06 BA10 CA14 CA15 CA24 CA29 CA34 CC11 CC13 DA02 DA03 DA06 DA10 4G014 AA00 AC00

Claims (7)

[Claims] An ash to be treated containing a halogen-based substance and a treating agent comprising an alkali substance containing a glass component are mixed and heated in a heat treatment furnace by an external heating means to decompose and precipitate from the ash to be treated. Glass with treated ash characterized by detoxifying decomposed gas, detoxifying ash to be treated and vitrifying by producing a harmless chloride by contacting the treated halogen-based material with a treating agent Treatment method. 2. An object to be treated containing a halogen-based substance and a treating agent made of an alkaline substance containing a glass component are mixed and heated in a heat treatment furnace by an external heating means to be decomposed and precipitated from the ash to be treated. By causing a harmless chloride by contacting a halogen-based substance with a treating agent to detoxify decomposed gas and detoxifying ash to be treated, Si, Na, and Ca, which are main components of soda glass, A vitrification method using treated ash, characterized in that vitrification is performed by controlling the amount of ash added. 3. The addition amount (% by weight) of the main component of soda glass is 65 to 75 for SiO ₂ , 10 to 20 for Na ₂ O,
The vitrification method using treated ash according to claim 2, wherein the CaO has a component ratio of 5 to 15. 4. An alkali material, an alkali metal, an alkali metal compound, an alkaline earth compound, an alkaline earth metal, which reacts with a halogen-based material decomposed and precipitated from ash to be treated by heating to form a harmless chloride. 3. The vitrification method using treated ash according to claim 1 or 2, wherein at least one kind is selected from substances contained in the compound, or two or more kinds are mixed. 5. The heating temperature of the external heating means is 500
The vitrification method using the treated ash according to claim 1 or 2, wherein the temperature is set to be from 800C to 800C. 6. The treated ash according to claim 1, wherein the ash to be treated is any one of incineration ash, fly ash, sludge incineration ash, dry sludge, and contaminated soils, or a mixture thereof. Vitrification treatment method. 7. A ash to be treated containing a halogen-based substance and a treating agent comprising an alkali substance are mixed and heated in a heat treatment furnace by an external heating means, and the ash to be treated is decomposed and precipitated from the ash to be treated. And the treating agent are contact-reacted to produce harmless chlorides, thereby detoxifying the decomposed gas and detoxifying the ash to be treated and obtaining molten glass, and forming the molten glass into a predetermined shape. A glass molded product made from treated ash, which is a molded product.