JP2003191045A - Method and facility for recovering casting sand composition from organic resin containing inorganic composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To safely recover and reuse inorganic compositions contained in an organic resin. <P>SOLUTION: A work formed of the organic resin containing the inorganic compositions such as silica as casting composition is heated by the external heat in a low oxygen atmosphere, the organic resin composition is decomposed and removed, and the inorganic composition is recovered. In particular, silica is used for a material of a casting sand. If the work contains chlorine, a chemical which is reacted in contact with chlorine obtained by heat- decomposing the work and deposited to generate harmless chlorides is added together with the work, and the work is subjected to the heating. More specifically, a facility for recovering the casting sand comprises a heating treatment device having decomposition furnaces 1 and 2 to heat-decompose the work consisting of the organic resin containing the inorganic composition in a low oxygen atmosphere by the external heating, a decomposition gas combustion furnace 3 in which the gas generated by the heat decomposition in the heat treatment device is fed, and the gas is burned, and a means 5 to recover residue containing the inorganic composition from the stuff fed from the heat treatment device. A gas combustion furnace 6 is provided as a burning means to burn the residue containing the inorganic composition in order to burn and remove the combustible compositions contained therein. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which an organic resin material containing inorganic particles such as silica (for example, epoxy resin molding residue, waste epoxy mold product, etc.) is thermally decomposed to remove organic components and silica. The present invention relates to an inorganic component recovery method and facility for recovering inorganic particles such as powder and reusing them as foundry sand.

[0002]

Epoxy resins are commonly used as electrical insulators or structural materials. As constituent components of this type of epoxy resin molded product, in addition to the epoxy resin and the curing agent, an inorganic agent such as silica (silicon dioxide) powder is mixed in order to lower the expansion coefficient of the cured product and reduce stress. There is.

The epoxy resin composition is bisphenol A.
It is important to carry out the treatment safely and surely because it contains endocrine disrupting substances such as.

On the other hand, silica powder has an average particle size of 10 μm.
It is a fine powder (having a particle size distribution of 1 to 200 μm), has a wide range of uses, and is useful as a precision instrument material or a building material.

[0005] Resin wastes such as epoxy resin products are generally crushed and granulated to be used as fuels for blast furnaces and the like, but they are also sources of dioxins and the aforementioned endocrine disrupting substances. Become.

By the way, as a technique for reusing the resin component of the epoxy resin molded product, JP-A-8-85736 is known as a technique for recovering an epoxy liquid material by thermal decomposition. According to this, the thermal decomposition of the resin is 340 to 9
It is preferable to heat within a temperature range of 00 ° C, particularly 350 to 450 ° C, and 510 to 5 when heated in an oxygen atmosphere.
Since the combustion reaction occurs at 40 ° C, it is desirable to heat at 500 ° C or lower.

Further, Japanese Patent Application Laid-Open No. 6-321521 is known as one in which a silicon compound such as silica powder is recovered from an epoxy resin molded product for recycling. According to this, the crushed epoxy resin composition is heat-treated at 1600 ° C. for 2 hours in a non-oxidizing atmosphere (argon atmosphere) to synthesize silicon carbide having a high added value and is collected.

[0008]

However, in order to recover silicon carbide, which is a silicon compound having a high added value, from an organic resin material such as an epoxy resin molded article, the above-mentioned Japanese Patent Laid-Open Publication No. 6-68242 has been proposed.
Reaction conditions as disclosed in US Pat.
It is necessary to create a very high temperature atmosphere such as 00 ° C,
Such means is not preferable because of high energy cost.

By the way, the epoxy resin molded product contains a large amount (50-80%) of inorganic components such as silica, which are rich in applications. Therefore, rather than costing energy costs to obtain high-value-added silicon carbide, recovering and recycling silica contained in the epoxy resin molded product without spending energy costs, for example, using silica as the main component. It is preferable to reuse it as foundry sand.

However, a technique for recovering an inorganic component contained in an organic resin material such as an epoxy resin molded product has not been established yet, and in particular, the means disclosed in Japanese Patent Laid-Open No. 8-85736 mentioned above is used in an oxygen atmosphere. Since it is heated, it may generate dioxins, and endocrine disruptors may remain.

The present invention has been made in view of the above circumstances, and an object thereof is to safely recover and reuse an inorganic component such as silica contained in an organic resin material such as an organic resin molded product. Another object is to provide a method and facility for recovering foundry sand components from organic resin materials containing inorganic components.

[0012]

Means for Solving the Problems The inventor has been able to decompose and remove an organic resin component by subjecting an organic resin material such as an epoxy resin product crushed in a low oxygen atmosphere to thermal decomposition (dry distillation) by external heating. It was found that inorganic components such as silica can be recovered and applied to foundry sand.

That is, according to the present invention, an object to be treated made of an organic resin material containing an inorganic component such as silica, which is a casting component, is heat-treated by external heating in a low oxygen atmosphere to decompose and remove the organic resin component. However, the inorganic component is recovered.

Some epoxy resin compositions contain a chlorine component, which causes the formation of dioxins. Therefore, when the object to be treated contains a chlorine component, it is advisable to add, together with the object to be treated, a chemical which produces a harmless chloride by catalytically reacting with chlorine decomposed and deposited by heating. This dechlorinating agent is a powder having a particle size of 1 to 100 μm, and an average particle size of several μm or less is effective, and although it depends on the amount of chlorine component contained in the resin,
30% by weight is added and mixed.

The dechlorinating agent is a chemical agent which reacts with chlorine to form a harmless chloride. For example, the inventors previously filed, alkali metals, alkali metal compounds,
It is effective to select at least one type of alkaline earth metal or alkaline earth metal compound or to mix two or more types.

Examples of the alkali metal compound include oxides, hydroxides, hydrogen carbonates, carbonates, silicates, aluminates, nitrates or sulfates of lithium, sodium, potassium, rubidium, cesium or francium. Etc.

Specific examples of the alkali metal compound treating agent include sodium hydrogen carbonate, sodium carbonate,
Examples thereof include sodium sesquicarbonate, natural soda, potassium carbonate, potassium hydrogen carbonate, sodium potassium carbonate, sodium hydroxide, potassium hydroxide and the like. In addition, sodium hydrogencarbonate is also referred to as sodium acid carbonate, sodium bicarbonate or sodium bicarbonate. Sodium carbonate is
It is also called sodium carbonate, soda, soda ash, laundry soda or crystalline soda. Sodium sesquicarbonate is also referred to as sodium monohydrogen dicarbonate, sodium hydrogen dicarbonate or sodium sesquicarbonate. Natural soda is also known as trona.

As the alkaline earth metal compound,
Examples thereof include oxides, hydroxides, hydrogen carbonates or carbonates of calcium, strontium, barium or radium.

Specific examples of the alkali metal compound treating agent include lime (CaO) and slaked lime (Ca (OH)).
₂ ), potassium carbonate (CaCO ₃ ) or dolomide (C
aCO ₃ · MgCO _3), and the like.

The facility for recovering inorganic components of the present invention for carrying out the method for recovering inorganic components heats an object to be treated which is made of an organic resin material containing inorganic components by external heating in a low oxygen atmosphere. A heat treatment device for decomposing,
A gas generated by thermal decomposition in the heat treatment apparatus is supplied, and a decomposition gas combustion furnace that combusts and processes this gas, and means for recovering a residue containing an inorganic component from the processed material supplied from the heat treatment apparatus are provided. It is characterized by that.

Here, the gas containing the decomposed organic resin component is burned in the cracked gas combustion furnace.

The recovery treatment facility may be equipped with a combustion means for burning a residue containing an inorganic component to burn off the combustible component contained therein.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

1 and 2 are schematic views showing an embodiment of a treatment facility for carrying out the method for recovering an inorganic component according to the present invention. The present invention is not limited to this form.

The recovery treatment facility comprises a first decomposition furnace 1, a second decomposition furnace 2 and a hot air stove 3. In the present embodiment, a thermal decomposition treatment apparatus having a configuration in which the first decomposition furnace 1 and the second decomposition furnace 2 are arranged in upper and lower two stages and the material to be treated is subjected to carbonization treatment is provided. That is, as shown in FIG. 1, the first decomposition furnace 1 and the second decomposition furnace 2 are arranged in two stages so that the supply port side of the second decomposition furnace 2 communicates with the discharge port side of the first decomposition furnace 1. To be done.
A communication duct 13 is provided on the discharge side of the first decomposition furnace 1 and the supply side of the second decomposition furnace 2 to cover the discharge side and the supply side and to communicate with each other. The heat-treated object is supplied to the second decomposition furnace 2.

The first decomposition furnace 1 adopts a rotary kiln system, forms a rotatable rotary cylinder 11 and a gas duct on the outer periphery of the rotary cylinder 11, and introduces hot air gas into the rotary cylinder 11 to the outside. A heating jacket 12 as an external heating means for heating from above, a supporting roller (not shown) that rotatably supports the rotating cylindrical body 11 at both ends, and a rotation driving means (not shown) for rotationally driving the rotating cylindrical body 11. , Are provided. The hot air gas is introduced from the hot air stove 3 described later.

The rotary cylinder 11 has a supply port side (not shown) for carrying in the object to be processed at one end side and a discharge port side (not shown) at the other end side, and a rotary cylinder (not shown) inside the cylinder body. A plurality of feed blades inclined with respect to the axis of the body 11 are provided. Then, the object to be treated supplied from the supply-side duct 10 is introduced into the rotary cylinder 11 from the side of the supply port, and the rotation of the rotary cylinder 11 causes the object to be treated to be transferred to the outlet side while stirring. Is possible. still,
The supply-side duct 10 is provided with a hopper (not shown) for introducing a mixture in which an object to be treated and a dechlorinating agent are mixed.

The second decomposition furnace 2 is a furnace for decomposing and precipitating the resin component remaining in the treated material supplied from the first decomposition furnace 1, and adopts a rotary kiln system to It has the same structure and includes a rotating cylinder 21 and a heating jacket 22. A detailed description of the configuration of the second decomposition furnace 2 will be given to the above description of the first decomposition furnace 1.

The hot-air stove 3 has a hot-air gas (for example, a temperature of 450).
It is a facility for generating and supplying (.about.600 ° C.) and is provided with a combustion burner 31 for generating hot air. The generated hot gas is supplied to the heating jacket 22 of the second decomposition furnace 2 to heat the rotating cylindrical body 21 of the second decomposition furnace 2, and then the connecting pipe 23
It is supplied into the heating jacket 12 of the first decomposition furnace 1 via. At this time, temperature adjustment air is sent in to adjust the temperature of the hot air gas. In this way, the first decomposition furnace 1 and the second decomposition furnace 2 are indirectly heated by the hot air gas from the outside, and the object to be treated inside is subjected to carbonization treatment.

The residue generated in the second decomposition furnace 2 is a mixture of inorganic silica and carbide. In the present embodiment, the separating device 5 separates the inorganic material (silica) from the carbide and recovers the inorganic material. The separation device 5 employs a specific gravity difference separation method as a separation means.
The separating device 5 is equipped with a conveying means 4 such as a screw or a spiral in order to introduce the mixture.

Further, as in the thermal decomposition treatment facility disclosed in FIG. 2, a carbide combustion device 7 may be provided instead of the separation device 5.

The carbide combustion device 7 is equipment for burning the treated material (carbide) whose volume has been reduced in the second decomposition furnace 2 to ash it. The processed material is introduced by a conveying means such as a pipe conveyor provided in the discharge side duct 24.

The carbide combustion device 7 is composed of a rotary furnace 71. The rotary furnace 71 is made of a tubular steel material, and a fireproof / heatproof layer (not shown) made of castable material is provided inside the tubular steel material. Has been. The rotary furnace 71 is supported on both sides in the axial direction by rotary rollers 72 and 73, and is provided with a means for rotating it by a drive source 74 composed of a motor M at the center.

The rotary furnace 71 is constructed so as to be inclined by 2 to 3 degrees in the traveling direction so that natural conveyance is possible. Further, inside the rotary furnace 71, there is provided a rotary transfer means (not shown) extending in the axial direction and projecting in the radial direction.

On the upstream side of the rotary furnace 71, that is, on the carbide charging side, a box-shaped charging jacket 75 seals 7.
7, which is provided via a means for conveying carbide (screw,
(Spiral) 4 and a combustion burner 76 for igniting and burning carbides.

Further, on the downstream side of the rotary furnace 71, that is,
On the ash discharge side, fireproof castable material inside
Box-shaped discharge jacket 7 with a heat-resistant layer (not shown)
8 is provided via a seal 79. The ash discharged from the discharge jacket 78 is collected in an ash collection box (not shown). The exhaust gas from the exhaust jacket 78 is supplied to the gas combustion processing furnace 6 via the pipe 80.

The gas combustion treatment furnace 6 burns the dry distillation gas generated in the first decomposition furnace 1 and the second decomposition furnace 2. Here, the dry distillation gas is introduced from the dry distillation gas conduit 60 through the ejector 61. At this time, in the gas combustion processing furnace 6,
Exhaust hot air gas from the heating jacket 12 is circulated blower 6
3 and an ejector blower 64 or other transfer means, and is introduced through the ejector 61. The dry distillation gas conduit 60 is kept warm by hot gas to prevent floating substances from adhering to the inner wall of the conduit.

The gas combustion processing furnace 6 has a gas combustion chamber for combusting the introduced gas. In the gas combustion chamber, the dry distillation gas and the exhaust gas generated in the carbide combustion device 7 are mixed and burned by the combustion burner 62. When the dry distillation gas is sufficiently generated, the combustion by the combustion burner 62 is appropriately limited by restricting the fuel supply. The gas that has been subjected to the high temperature combustion treatment is used in the heat exchanger 65 and the bag filter 6.
6, exhausted through the exhaust blower 67 and chimney 68 to the outside of the system.

An operation example of the inorganic component recovery processing facility will be outlined.

First, in the first decomposition furnace 1, an object to be treated (a resin molded body is crushed, and the size is, for example, 10 to 2).
Dechlorinating agent mixed with 0 mm square under) (for example,
Sodium hydrogen carbonate (amount added: 10% by weight) is added, and dry distillation treatment is performed under an atmosphere of 300 to 400 ° C. and a constant residence time (for example, about 30 minutes). At this time, resin forming components such as chlorine contained in the object to be treated are decomposed and deposited from the object to be treated. Further, the chlorine component reacts with the dechlorinating agent added and mixed, and is replaced with harmless chloride to form. Further, the other decomposed and precipitated resin components are subjected to combustion treatment in the gas combustion treatment furnace 6 via the dry distillation gas introduction path 60, and under a constant atmosphere and residence time (for example, in an atmosphere of about 850 ° C.). And a detoxification treatment of 2 seconds or more).

Next, in the second decomposition furnace 2, the first decomposition furnace 1
The treated product supplied from the above is subjected to dry distillation treatment at 450 to 550 ° C., whereby the resin component remaining in the treated product is further decomposed and deposited, and the resin component is removed. The decomposed and deposited component is supplied to the gas combustion treatment furnace 6 and is detoxified.

The decomposition gas (dry distillation gas) generated by the thermal decomposition treatment in the first and second decomposition furnaces 1 and 2 is transferred together with a part of the hot air gas and fresh air by the dry distillation gas introduction pipe 60. Is introduced into the gas combustion processing furnace 6 via the and is subjected to combustion processing.

The residue generated by the thermal decomposition treatment in the second decomposition furnace 2 is a mixture of inorganic substances (such as silica) and carbide. The mixture is supplied to the separation device 5 or the carbide combustion device 7 by the conveying means 4, and the inorganic component such as silica is recovered. In particular, silica is used as a material for foundry sand.

[0044]

As is clear from the above description, the method for recovering inorganic components and the facility therefor according to the present invention have the following effects.

(1) Since the resin constituent components of the resin body are decomposed and removed by heating, the contained inorganic components can be reliably separated and recovered and can be reused.

(2) Bisphenol A contained in the resin body
Since harmful components such as are decomposed and deposited and burned, safe and reliable detoxification can be performed.

(3) By adding a dechlorinating agent for treatment, the generation of dioxins can be effectively suppressed.

[Brief description of drawings]

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

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

[Explanation of symbols]

1 ... First decomposition furnace 2nd second decomposition furnace 3 ... hot stove 4 ... Transport means 5 ... Separation device 6 ... Gas combustion treatment furnace 7 ... Carbide combustion furnace

Claims (5)

[Claims] 1. An object to be treated, which is made of an organic resin material containing an inorganic component such as silica as a casting component, is heat-treated by external heating in a low oxygen atmosphere to decompose and remove the organic resin component to obtain an inorganic substance. A method for recovering a foundry sand component from an organic resin material containing an inorganic component, characterized by recovering the component. 2. When the substance to be treated contains a chlorine component, a chemical agent which produces a harmless chloride by reacting with the chlorine which has been analyzed by heating is added together with the substance to be treated for heat treatment. The method for recovering a foundry sand component from an organic resin material containing an inorganic component according to claim 2. 3. A method for recovering a foundry sand component from an organic resin material containing an inorganic component according to claim 1 or 2, characterized in that the gas generated by heat-treating the object to be treated is further burned. . 4. A heat treatment device for thermally decomposing an object to be treated made of an organic resin material containing an inorganic component such as silica, which is a foundry sand component, by external heating in a low oxygen atmosphere, and heat in the heat treatment device. A decomposition gas combustion furnace which is supplied with gas generated by decomposition and burns the gas, and means for recovering a residue containing an inorganic component from a processed material supplied from a heat treatment apparatus, are provided. Inorganic component recovery processing facility. 5. The facility for recovering and treating inorganic components according to claim 4, further comprising a burning means for burning and removing combustible components contained therein by burning the residue containing the inorganic components.