JP4062789B2 - Detoxification method for firebrick or mortar containing dioxins - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a treatment method for detoxifying solids containing harmful organic chlorine compounds such as dioxins, for example, refractory bricks used in incinerators.
[0002]
[Prior art]
In recent years, existing incinerators have been abolished or modified due to the need to suppress the generation of hazardous substances such as dioxins associated with incineration of waste, etc., but the fireproofing used in the furnace at that time A lot of bricks are put out as waste.
The refractory brick used in this incinerator contains a large amount of organic chlorine compounds such as dioxins and cannot be landfilled or discarded as it is.
On the other hand, as a process for completely decomposing harmful substances such as sludge and dioxins, a method using a supercritical water / hydrothermal reaction process has been developed.
[0003]
[Problems to be solved by the invention]
As mentioned above, some harmful organochlorine compounds such as dioxins are very stable in the natural environment, so if you dispose of used refractory bricks in an incinerator as they are, they will leach into the soil and accumulate. There was a risk that it would flow out due to rainwater. If supercritical water / hydrothermal reaction is used, dioxins adhering to the incinerator refractory bricks can be decomposed in principle, but the amount of dioxins in the refractory bricks is very small. As a result, the hydrothermal treatment apparatus may be blocked by an inorganic solid that is a brick component.
[0004]
The present invention has been made in view of the above-mentioned problems, and detoxifies solids containing organic chlorine compounds such as refractory bricks used in incinerators so that they can be disposed of in a natural environment before hydrothermal treatment. Another object of the present invention is to provide a method for detoxifying a solid containing an organic chlorine compound, which can separate a solid and reduce the amount of the treatment.
[0005]
[Means for Solving the Problems]
The present invention employs the following configuration in order to solve the above problems. That is, in the first invention, there is a processing method for detoxifying a refractory brick or mortar containing dioxins, a pulverizing step of pulverizing the refractory brick or mortar into a powder, and the powder after the pulverizing step. An extraction process for adding an organic solvent to the extraction tank and adding the organic solvent to the extraction tank; a solid-liquid separation process for separating the powder to which the organic solvent has been added into a solid content and a liquid content; and the pulverization process, the extraction process or the solid-liquid separation step in the powder or water addition step of adding water to the liquid fraction, the dioxin to cause a to hydrothermal reaction in addition to a high-temperature high-pressure state of sodium hydroxide in the liquid fraction after the solid-liquid separation step And a hydrothermal reaction treatment process for decomposing substances.
[0006]
In this detoxification process, by pulverizing a refractory brick or mortar in the grinding step to a powder, since an organic solvent is added to the powder in the extraction vessel in the extraction step, containing the adhesion and internal surfaces of the refractory bricks or mortar Dioxins are selectively dissolved in an organic solvent in the extraction tank, extracted, separated and concentrated. Then, since the solid and liquid components are separated in the solid-liquid separation step, the solid refractory brick powder or mortar powder and the organic solvent (liquid component) from which dioxins are extracted are separated, and only this liquid component is later. Hydrothermal treatment is performed in the hydrothermal reaction treatment step. At this time, the organic solvent of the liquid is also decomposed by the hydrothermal treatment and becomes harmless. In addition, since an organic solvent is not added at the time of a grinding | pulverization process, it is not necessary to use a nonflammable or a flame-retardant organic solvent in consideration of the spark at the time of a grinding | pulverization, and it can also use a combustible organic solvent.
[0007]
In 2nd invention , the technique which returns a part of solid content isolate | separated at the said solid-liquid separation process to the said extraction tank in 1st invention is employ | adopted.
[0008]
In this detoxification treatment method, a part of the solid content separated in the solid-liquid separation step is returned to the extraction tank, so that the extraction of dioxins can be repeated, and the solid content can be sufficiently extracted.
[0009]
In the third aspect, in the first or second invention, the extraction step, a technique for agitating said organic solvent and said powder by the extraction tank is employed.
[0010]
In this detoxification treatment method, since the powder and the organic solvent are stirred in the extraction tank in the extraction step, the powder can be sufficiently dispersed in the organic solvent by sufficiently mixing them.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a detoxification method for refractory bricks or mortar containing dioxins according to the present invention will be described with reference to FIG.
[0012]
FIG. 1 shows an implementation facility in a method for detoxifying used refractory bricks of an incinerator . The facility includes a coarse pulverizer 1 that pulverizes used refractory bricks to a size of approximately 10 cm or less, and a medium pulverizer that pulverizes used refractory bricks crushed by the coarse pulverizer 1 to a size of approximately 1 cm or less. 2, a fine pulverizer 3 that wet-grinds the used refractory bricks pulverized by the medium pulverizer 2 into brick powder having a size of several mm to 10 μm or less to form a slurry, and the slurry and the organic solvent. Extraction tank 4 for extracting dioxins contained in the mixed slurry, separation tank 5 for solid-liquid separation of the solid and liquid components from the slurry and organic solvent extracted in the extraction tank 4, and the separation tank And a hydrothermal treatment device 6 for hydrothermal reaction treatment of the liquid component separated in 5 under high temperature and high pressure conditions.
[0013]
The coarse pulverizer 1 and the intermediate pulverizer 2 have a function of sprinkling water during pulverization. As the coarse pulverizer 1, for example, a jaw crusher, a gyratory crusher, or the like is used. For example, a gyratory crusher, a crushing roll, a hammer mill, a roller mill or the like is used.
As the fine pulverizer 3, a ball mill, a roller mill or the like is used.
As said organic solvent, toluene, acetone, etc. are employ | adopted, for example. A non-flammable or flame retardant organic solvent may be used, but even if a flammable organic solvent as described above is employed, a place where sparks or the like may occur as in each of the above pulverizers. There is no risk of fire, etc.
[0014]
The extraction tank 4 has a stirring function for mixing the slurry sent from the pulverizer 3 and the added organic solvent (for example, using a propeller-shaped rotary blade generally used).
For example, a filter or a cyclone is used as the separation tank 5.
The hydrothermal treatment apparatus 6 includes an addition mechanism (not shown) for adding NaOH to the liquid component to be sent, and supercritical water in a high-temperature and high-pressure state such as 300 ° C. or higher and 10 MPa or higher. Alternatively, a pressure vessel (not shown) for causing a hydrothermal reaction is provided.
[0015]
A method for detoxifying used refractory bricks by this facility will be described below with reference to FIG.
[0016]
[Crushing process]
"Rough grinding process"
First, the used refractory bricks are supplied to the coarse pulverizer 1 and pulverized while being sprinkled with the coarse pulverizer 1 to make the used refractory bricks into a pulverized product having a size of about 10 cm or less.
[0017]
"Medium grinding process"
Next, the pulverized product obtained by the coarse pulverization step is sent from the coarse pulverizer 1 to the intermediate pulverizer 2 and pulverized with water sprayed by the intermediate pulverizer 2 to obtain a pulverized product having a size of about 1 cm or less.
In this way, in the coarse pulverization step and the intermediate pulverization step, pulverization is performed while sprinkling water, so that generation of dust can be suppressed. The water sprayed can be used as a raw material for the hydrothermal reaction in the subsequent hydrothermal reaction treatment step.
"Fine grinding process"
Furthermore, water was added to the pulverized product in the intermediate pulverization step, and the pulverized product was sent from the intermediate pulverizer 2 to the fine pulverizer 3 and wet pulverized by the fine pulverizer 3 to contain brick powder having a size of several mm to 10 μm or less. Adjusted to slurry.
[0018]
[Extraction process]
The slurry is sent to the extraction tank 4, and an organic solvent is added to the extraction tank 4. At this time, the slurry and the organic solvent are sufficiently mixed by the stirring function, and the organic chlorine compounds such as dioxins contained in the powder in the slurry are dissolved in the organic solvent and extracted and concentrated.
[0019]
[Solid-liquid separation process]
The slurry and organic solvent extracted in the extraction tank 4 are sent to the separation tank 5 to separate the solid content, that is, the inorganic solid content of the refractory brick, and the liquid content, that is, the organic solvent and water in which dioxins are dissolved. In addition, a part of solid part isolate | separated here is returned to the extraction tank 4, and extraction of dioxins is performed by a repeating extraction process. That is, the separated solid content is a solid matter in which dioxins are extracted and separated and detoxified.
[0020]
[NaOH addition process]
Next, the liquid remaining in the hydrothermal treatment apparatus 6 is sent from the separation tank 5 and NaOH (sodium hydroxide) is added by an addition mechanism.
[0021]
[Hydrothermal reaction treatment process]
The liquid component to which NaOH is added is introduced into the pressure vessel of the hydrothermal treatment apparatus 6, and a hydrothermal reaction occurs in the high-temperature high-pressure water in the pressure vessel. Note that the inside of the pressure vessel is kept at a pressure of 300 ° C. or higher and 10 MPa or higher.
[0022]
At this time, organic chlorine compounds such as dioxins contained in the liquid are decomposed by a hydrothermal reaction, and the chlorine component therein reacts with NaOH to form a harmless and stable salt (NaCl), which is not re-synthesized. It becomes. At the same time, the organic solvent is also decomposed by the hydrothermal reaction and rendered harmless.
If the hydrothermal reaction treatment step is performed in a supercritical water atmosphere, that is, high-temperature high-pressure water at 374 ° C. or higher and 22 MPa or higher, the organic chlorine compound can be dissolved almost uniformly into water in a decomposed state.
[0023]
The liquid component treated in the hydrothermal reaction treatment step becomes water containing NaCl and NaOH, and no dioxins remain, so that it is discharged or reused after the waste water treatment.
[0024]
In addition, this implementation facility is designed in a size that can be mounted on a truck or the like as a whole, and can be directly moved to a predetermined incineration site. This eliminates the need to transport used refractory bricks (industrial waste) outside the incinerator.
Moreover, although the refractory brick used in the incinerator was detoxified as a solid containing an organic chlorine compound, it may be applied as a means for detoxifying other solids. For example, you may use for the method of detoxifying other materials (mortar etc.) in an incinerator.
Furthermore, when extraction of dioxins or the like is insufficient in one extraction tank, a plurality of extraction tanks may be configured in a multistage manner and extracted.
[0025]
【The invention's effect】
The present invention has the following effects.
(1) According to the first invention , a pulverizing step of pulverizing refractory bricks or mortar to form a powder, an extracting step of adding the organic solvent into the extraction tank, and a solid component and a liquid component A solid-liquid separation step for separating, a water addition step for adding water to the powder or liquid, and a hydrothermal reaction treatment step for causing a hydrothermal reaction by adding sodium hydroxide to the liquid after the solid-liquid separation step. Therefore, not only the surface of the refractory brick or mortar but also the internal dioxins can be easily extracted into the organic solvent in the extraction tank by pulverization, and the extraction rate can be improved. Moreover, the solid content from which dioxins were removed can be separated by the solid-liquid separation step before the hydrothermal treatment, and the detoxified solid content can be discarded in the natural environment. Furthermore, in the hydrothermal reaction process, only the liquid content excluding the solid content is processed, so that the processing amount can be greatly reduced and the organic solvent is also decomposed by the hydrothermal reaction. There is no discharge. Further, in the extraction process, an organic solvent is added to the slurry after pulverizing the refractory brick or mortar , so that a flammable organic solvent that could not be added during the pulverization process can be employed, such as toluene and acetone. Common organic solvents can be used.
[0026]
(2) According to the second invention , since a part of the solid content separated in the solid-liquid separation step is returned to the extraction tank , the extraction of dioxins can be repeated, and the solid content can be sufficiently extracted. it can.
[0027]
(3) According to the third invention , since the powder and the organic solvent are stirred in the extraction tank in the extraction step, the two are sufficiently mixed to sufficiently disperse the powder in the organic solvent, and efficiently Dioxins can be extracted.
[Brief description of the drawings]
1 is a connection diagram showing an exemplary equipment in an embodiment of the detoxification method of the refractory bricks or mortar containing dioxins according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Coarse grinder 2 Medium grinder 3 Fine grinder 4 Extraction tank 5 Separation tank 6 Hydrothermal treatment apparatus

Claims (3)

A treatment method for detoxifying refractory bricks or mortar containing dioxins ,
A pulverizing step of pulverizing the refractory brick or mortar to powder;
An extraction step of putting the powder into an extraction tank after the grinding step and adding an organic solvent to the extraction tank;
A solid-liquid separation step of separating the powder to which the organic solvent is added into a solid component and a liquid component;
A water addition step of adding water to the powder or the liquid component in the pulverization step, the extraction step or the solid-liquid separation step;
Dioxins, characterized in that it comprises a said solid-liquid separation step after the liquid fraction was added sodium hydroxide in the high temperature and high pressure condition to cause a hydrothermal reaction decompose hydrothermal reaction of the dioxins process Detoxifying treatment method for refractory bricks or mortar containing slag . The method for detoxifying refractory bricks or mortar containing dioxins according to claim 1, comprising dioxins characterized in that a part of the solid separated in the solid-liquid separation step is returned to the extraction tank. Detoxification method for firebrick or mortar . In detoxification method of the refractory bricks or mortar containing the claims 1 or 2 dioxins, wherein the extraction step, dioxins, which comprises stirring said organic solvent and said powder by the extraction tank Detoxifying treatment method for refractory bricks or mortar containing slag .

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