JP7197909B2 - Method and apparatus for treating mixtures containing various waste polymers, waste metals, and waste organic/inorganic substances - Google Patents

Description

The present invention relates to a method and apparatus for treating mixtures containing various waste polymers, waste metals, and waste organic and inorganic substances.

Disposal of electric appliances and the like has become a big social problem in recent years. Recycling of electronic parts is progressing, and it is welcomed in the environmental field. However, the disposal of industrial mixed waste remaining at the final stage of the recycling process is not easy.
In the past, electrical appliances were disassembled by hand, circuit boards and metal parts were carefully removed, and various polymer composite compounds were carefully sorted to avoid mixing and recycled. Therefore, most of the mixed waste finally remaining was small, and the amount thereof was not so large. This mixed waste was called export and was requested to be processed in Southeast Asian countries. However, the manual sorting work is labor-intensive and time-consuming, and labor costs have skyrocketed.
In recent years, in order to reduce recycling costs, instead of disassembling and sorting electrical appliances in general, methods such as cutting by a large hammer or guillotine method have been adopted. Metals such as iron are first removed from the cut material using magnets, and metals such as Al that do not stick to magnets are attracted to magnets by inducing magnetism through electromagnetic induction, after which they are blown away by wind and collected. there is In addition, relatively large polymer complex compounds are picked up and sorted. However, in exchange for cost reduction, various polymer complex compounds and various polymers (thermoplastic and thermosetting polymers, vinyl chloride products, sulfur-containing polymers such as tires, etc.) are not separated and are collectively processed. there is Furthermore, it is in a state in which various pieces of electric wire (coating material: polyvinyl chloride, polyethylene, etc.), metal pieces, rubbers, etc. are mixed. Such remnants are relatively large pieces of garbage, doubling the amount of garbage. From the above progress, the recent recycling of electrical appliances, etc., is characterized by being composed of mixtures of various composite materials, polymers, metals, etc., and bulky, although the cost has been reduced. These "mixed garbage that cannot be processed" were requested to be processed by China, Thailand, the Philippines, Vietnam, etc. under the guise of "export". However, since the incineration produces terrible odors and harmful gases, these countries have been notified of refusal to accept the waste, and Japanese waste disposal companies are piled up with "waste plastics/waste electric wires". Medical waste such as syringes and catheters is in a similar situation.

Disposal of these composite wastes by conventional incineration methods not only causes very unpleasant odors, but also poses a threat to human health. The odor includes gases containing chlorine and sulfur, and is an unimaginable odor. There is a strong demand for a processing method and a processing apparatus capable of decomposing and processing without generating harmful gases and recovering valuables from the residue after processing.

One of the inventors of the present invention has proposed a method for decomposing an object to be treated consisting of an organic substance such as a polymer or a gas by heating a semiconductor to a temperature at which it becomes an intrinsic electrical conduction region to generate a large amount of electron/hole carriers, "Thermal Activation of Semi-Conductors" (hereinafter abbreviated as TASC) that completely decomposes the object to be treated in the presence of oxygen by bringing the object into contact with holes that have a strong oxidizing power generated by heat treatment. (Patent Document 1, Non-Patent Document 1). This phenomenon is due to the strong oxidizing effect (strong ability to extract bond electrons) when the semiconductor is heated to 350-500°C. This propagates within the polymer and proliferates further, destabilizing the entire polymer. A destabilized polymer cannot maintain its stability and is induced to fragment in a self-defeating manner to fragment into small molecules such as propane. Subsequently, the shredded small molecules react with oxygen in the air and are completely decomposed into carbon dioxide and water. In other words, all polymers (thermoplastic polymers and thermosetting polymers) are instantaneously decomposed into carbon dioxide gas and water by the TASC catalyst in the presence of oxygen. As described above, the TASC decomposition process includes (1) the process of generating radicals due to oxidative power, (2) the process of destabilizing macromolecules and decomposing them into small molecules due to the propagation of radicals, and (3) the process of small molecules. It is composed of three elementary processes of complete combustion of oxygen in the air and complete combustion of the atomized molecules.
A semiconductor that can be used in the TASC method may be a semiconductor that is stable at a high temperature in an oxygen atmosphere. Therefore, an oxide semiconductor is preferably used. Examples of oxide semiconductors include BeO, CaO, CuO, Cu2O, _SrO2 , BaO, MgO, NiO, _CeO2 , MnO, GeO, PbO, TiO, VO, ZnO, FeO, _PdO , _Ag2O , TiO ₂ , _{MoO2 , PbO2} , IrO2, _RuO2 , _Ti2O3 , ZrO2, _Y2O3 , _{Cr2O3 , ZrO2} , _{WO3 , MoO3 , WO2} , _{SnO2 , Co3O 4} , _{Sb2O3 , Mn3O4 , Ta2O5 , V2O5 , Nb2O5 , MnO3 , Fe2O3 , Y2O2S , MgFe2O4 , NiFe2O4} , ZnFe ₂ O ₄ , ZnCo ₂ O ₄ , MgCr ₂ O ₄ , FeCrO ₄ , CoCrO ₄ , CoCrO ₄ , ZnCr ₂ O ₄ , CoAl ₂ O ₄ , NiAl ₂ O ₄ and the like. Among them, chromium oxide (Cr ₂ O ₃ ) is excellent in high temperature stability (melting point: about 2200° C.) and is a safe material used for dyeing glass bottles for beverages. In addition, iron oxide (α-Fe ₂ O ₃ : hematite) is not as stable as Cr ₂ O ₃ , but it is a safe and inexpensive material, so it is highly practical.

In addition, using the same TASC method for fiber-reinforced plastics, we have proposed a method for completely decomposing plastics and completely recovering reinforcing fibers such as carbon fibers and glass fibers without damaging them (Patent Document 2, Non-Patent Document 2). ). This method is very useful because it is possible to recover and reuse reinforcing fibers without damaging fibers such as carbon fibers, which are particularly expensive, by cutting them. It is a universal method that can recover only inorganic substances from composite materials mixed with polymers.
In addition, a VOC (Volatile Organic Compounds) purifying device is connected to the heat treatment chamber, and plastic or plastic composite materials such as solar panels and laminated glass are decomposed by the TASC method and purified into harmless gases. A device was also proposed (Patent Documents 3 and 4).
The oxide semiconductor used in the TASC method is called a TASC catalyst, which is classified as a "catalyst" in the sense that it can be used any number of times. However, it has a completely different function from ordinary chemical catalysts. A chemical catalyst forms an active complex between a catalyst substance and a reactant, lowers the activation energy, and allows the reaction to proceed at a lower temperature. On the other hand, the TASC catalyst destabilizes the decomposable substances such as polymers by the mechanism described above, further reduces the molecular weight of the substances, and completely burns them in the presence of sufficient oxygen.

In this way, the TASC effect has been utilized to completely decompose organic gases (VOC, exhaust gas, offensive odors, etc.) or mist-like tar, PM, and the like. Furthermore, in solids, it has been used to decompose only the polymer of polymer composite compounds and recover valuable substances from inside. Examples include the recovery of carbon fiber from FRP (Fiber Reinforced Plastic), glass, silicon wafers and electrodes from solar panels, rare earth powder from bonded magnets, and glass from laminated glass. .
Chlorine compounds are widely used in the industrial world (various pipes, wire coatings, etc.) as polymer materials represented by vinyl chloride. In particular, the material called "vinyl chloride" contains many plasticizers and flame retardants in vinyl chloride. When these materials are incinerated, hydrochloric acid and dioxins are likely to be generated at 180-400°C, and caution is required as these may scatter outside. As for sulfur, there are sulfur-containing polymers (for example, polyphenylene sulfide) and sulfur compounds as cross-linking agents for rubbers. Sulfur becomes H ₂ S, H ₂ SO ₄ and the like, and often scatters.
We also proposed a treatment method that decomposes organic wastes containing sulfur, halogens, and silicon as components by the TASC method and captures them in the residue as metal sulfides, metal halides, and silicon oxides without generating harmful gases ( Patent document 5).
For example, thermal activation of hematite decomposes halogen and sulfur-based polymers. The halogen and sulfur components liberated at the same time as the decomposition immediately react with Fe in hematite to form FeCl ₂ (greenish yellow), FeCl ₃ (dark brown), FeS (black), FeS ₂ , Fe ₂ S ₃ and Fe ₂ , respectively. It is immobilized as _S4 and the like. Therefore, it does not scatter to the outside air.
The characteristics of the composite material to be processed by the present invention are enumerated. The characteristics of the current pulverized and cut waste are mainly various polymer composite materials (i) (containing no chlorine or sulfur components), chlorine-sulfur plastic composite materials (ii), PVC electric wires, tires, etc. A small amount of metal scraps are mixed in this. Another characteristic is that these wastes are extremely bulky. Composite debris is generally about 1-2 mm thick, but most are 50-150 mm wide and long. Also, the electric wire or the like has a diameter of 1 to 3 mm and a length of about 50 to 100 mm. In addition, the metal dust is beaten and cut in the pulverization and cutting process, so that the metal dust is irregularly piled up and has a thickness of 1 to 3 mm and a width and length of about 20 to 50 mm.
The TASC method is applied to the treatment of mixtures containing various bulky and large-sized waste polymers, waste metals, waste organic and inorganic substances, and components that generate harmful gases such as sulfur, chlorine, and silicon. However, an efficient method for separating and removing residues from the residues after treatment and recovering only valuables such as metals has not been solved.

Patent No. 4517146 Patent No. 5904487 JP 2016-93804 A JP 2016-172246 A Patent No. 6429177

T. Shinbara, T.; Makino, K.; Matsumoto, andJ. Mizuguchi: Complete decomposition of polymers by means of thermally generated holes at high temperatures in titanium dioxide and its decomposition mechanism, J. Am. Appl. Phys. 98, 044909 1-5 (2005) Hitoshi Mizuguchi: Complete Decomposition and Recycling Technology of FRP by Thermal Activation of Semiconductor, Processing Technology Vol.47, 37-47 (2012)

The present invention detoxifies inorganic/organic mixed waste, which consists of polymers or polymer composite compounds containing at least one of sulfur, halogen, and silicon, as well as metal pieces, etc., without generating harmful gases, and further waste metals. It is an object of the present invention to provide a processing method and a processing apparatus capable of sorting and collecting valuables such as waste.

According to the present invention, there is provided a method for treating a mixed inorganic-organic waste composed of a polymer or a polymer composite compound containing at least one of sulfur, halogen, and silicon, and metal pieces, etc., and an oxide semiconductor is formed on the surface of the waste. a step of coating, a step of storing the waste coated with the oxide in a processing container having a large number of holes having a hole diameter of 1 mm or more and 30 mm or less on the bottom surface and placing the waste in a heat treatment chamber; Second, at a temperature at which a large amount of holes and electrons are generated by the interband transition of the oxide semiconductor, the oxidizing power of the holes is used to decompose the organic matter in the waste into water and carbon dioxide. a step of converting the sulfur component contained in the waste into a metal sulfide, converting the halogen component into a metal halide, and capturing the silicon component into the residue as a silicon oxide; The method is characterized by including a step of separating the residue from the processing container by dropping the residue through a hole in the bottom surface of the container, and a step of recovering the valuable metal from the fixed inorganic matter remaining in the processing container.

According to the present invention, there is provided a method for treating a mixed inorganic-organic waste composed of a polymer or a polymer composite compound containing at least one of sulfur, halogen, and silicon, and metal pieces, etc., and an oxide semiconductor is formed on the surface of the waste. and placing the waste coated with the oxide in a heat treatment chamber, in the presence of oxygen at a temperature at which a large number of holes and electrons are generated by interband transitions of the oxide semiconductor. and decomposing the organic matter in the waste into water and carbon dioxide by utilizing the oxidizing power of the holes, converting the sulfur component contained in the waste into a metal sulfide, and replacing the halogen component with a metal halide. and a step of capturing the silicon component in the residue as silicon oxide; It is characterized by including a step of separating the residue by dropping it through a hole in the plate-like portion, and a step of recovering the valuable metal from the fixed inorganic matter remaining on the plate-like portion.

According to the present invention, there is provided an apparatus for treating inorganic/organic mixed waste composed of a polymer or a polymer composite compound containing at least one of sulfur, halogen, and silicon, and metal pieces, etc., and an oxide semiconductor is formed on the surface of the waste. A processing container having a bottom surface with a large number of holes having a hole diameter of 1 mm or more and 30 mm or less for storing the waste coated with the oxide, and a heat processing chamber having an air supply mechanism for supplying air. , the processing container installed in the heat processing chamber is heated to a temperature equal to or higher than a temperature at which a large amount of holes and electrons are generated by interband transition of the oxide semiconductor, thereby reducing the number of holes in the presence of oxygen. The organic matter in the waste is decomposed into water and carbon dioxide using oxidizing power, and the sulfur component contained in the waste is changed to metal sulfide, the halogen component is changed to metal halide, and the silicon component is captured in the residue as a silicon oxide, is separated from the processing container by vibrating the processing container, and the residue falls through the hole in the bottom of the processing container, and is separated from the fixed inorganic matter remaining in the processing container. It is characterized in that valuable metals are recovered.

According to the present invention, there is provided an apparatus for treating inorganic/organic mixed waste composed of a polymer or a polymer composite compound containing at least one of sulfur, halogen, and silicon, and metal pieces, etc., and an oxide semiconductor is formed on the surface of the waste. A heat treatment chamber is provided in which the waste coated with the oxide is placed, the heat treatment chamber has an air supply mechanism for supplying air, and the waste placed in the heat treatment chamber is the By heating above the temperature at which a large amount of holes and electrons are generated by the interband transition of the oxide semiconductor, the organic matter in the waste is decomposed using the oxidizing power of the holes in the presence of oxygen. While being decomposed into water and carbon dioxide, the sulfur component contained in the waste is converted to metal sulfide, the halogen component is converted to metal halide, and the silicon component is captured as silicon oxide in the residue, and the hole diameter is reduced. A plate-shaped portion having a large number of holes of 1 mm or more and 30 mm or less is separately provided outside the heat treatment chamber, and the residue is separated by vibrating the plate-shaped portion and dropping the residue through the holes of the plate-shaped portion. and the valuable metal is recovered from the fixed inorganic matter remaining on the plate-like portion.

The objects to be treated in the present invention are polymers or polymer composite compounds containing at least one of sulfur, halogen, and silicon, as well as inorganic/organic mixed wastes such as metal fragments. When the surface of the waste is coated with an oxide semiconductor, placed in a heat treatment chamber, and heated in the presence of oxygen to a temperature higher than the temperature at which a large amount of holes and electrons are generated by interband transition of the oxide semiconductor, Using the oxidizing power of holes, the organic matter in the waste is decomposed into water and carbon dioxide, and the sulfur component contained in the waste is changed to metal sulfide, the halogen component is changed to metal halide, and the silicon component is captured in the residue as silicon oxide.
Waste coated with an oxide semiconductor is stored in a processing container having a large number of holes with a hole diameter of 1 mm or more and 30 mm or less on the bottom surface, placed in a heat treatment chamber, and subjected to heat treatment. After treatment, the treatment container is vibrated. is applied to cause the residue to drop through the hole in the bottom surface of the processing container, thereby separating the residue from the processing container and then removing the processing container from the heat treatment chamber. Valuable metals are recovered from the removed processing container.
The processing container is typically a stainless steel basket that acts as a sieve, but if the hole diameter of the bottom is set to 1 mm or more and 30 mm or less, the metal sulfide, metal halide, and silicon oxide after processing are powdered. Since it is sometimes lightly sintered, it usually falls through the small holes by applying a light vibration, and bulky metal and inorganic residues hardly pass through the holes and stay in the stainless steel cage. Vibration may be applied manually or by a mechanical automatic vibration device. A hole diameter of 5 mm or more and 15 mm or less is optimal because it more completely prevents fixed inorganic substances, which are residues of metals and inorganic substances, from passing through the holes, and makes it easier for the residues to fall through the holes.

The treatment container is not installed in the heat treatment chamber before heat treatment, and after heat treatment, vibration is applied outside the heat treatment chamber to separate and remove metal sulfides, metal halides, and silicon oxides, and to remove valuables from the residue. The metal may be recovered. This method is a semi-automated apparatus capable of moving the heat treatment furnace, and is suitable for a batch-type continuous apparatus. In such a semi-automated apparatus, since an open system may cause a fire during heat treatment, it is necessary to perform the treatment in a closed system for safety.
Various oxide semiconductors as described above can be used to coat the surface of the waste, but in the present invention, it is preferable to use the cheapest iron oxide (α-Fe ₂ O ₃ : hematite). . Iron oxides include α-Fe ₂ O ₃ , γ-Fe ₂ O ₃ and Fe ₃ O ₄ , and α-Fe ₂ O ₃ is widely known as a red inorganic pigment called hematite or red iron oxide. It is

According to the present invention, not only is the organic matter in the waste mixture completely decomposed into water and carbon dioxide gas, but valuable metals can be recovered efficiently and inexpensively. In addition, even if sulfur, halogen, and silicon are contained as components, they are captured in the residue without generating harmful gases, so a safe recovery method and recovery apparatus can be provided without polluting the environment.

1 shows a device for treating waste; FIG. This is mixed waste of "waste plastic/metal scrap" before hematite coating. This is mixed waste of "waste plastic/metal scrap" after hematite coating. The powdery residue (upper part) separated after the heat treatment and the metal residue (lower part) remaining in the stainless steel cage are shown side by side. The powdery residue (top) separated after heat treatment of another sample and the residue (bottom) of several glass fiber woven fabrics remaining in the stainless steel basket are shown side by side.

FIG. 1 is a diagram showing a method and apparatus for treating waste containing a mixture of valuable metals and organic matter according to the present invention. First, an oxide semiconductor 2 is coated on the surface of a waste 1 which is an object to be treated. As a method for coating the surface of the waste 1 with the oxide semiconductor 2, a method of dip-coating the object to be processed in a suspension of the oxide semiconductor 2 is most suitable. As the oxide semiconductor 2, it is preferable to use the cheapest hematite (iron oxide, α-Fe ₂ O ₃ ) because it is used only once.
A waste material 1 coated with an oxide semiconductor 2 is placed in a processing container 3 having a large number of holes with a hole diameter of 1 mm or more and 30 mm or less on the bottom surface, and placed in a heat treatment chamber 4 . The processing container 3 is preferably a basket made of stainless steel. When the heat treatment chamber 4 is a batch type furnace, it is preferable to put the waste 1 in the basket 3 and install it in the heat treatment chamber 4 for the convenience of taking out the waste 1 after treatment. However, when the material to be treated is a tunnel furnace that passes through the heat treatment chamber 4, the front and rear of the tunnel furnace are sealed with shield doors for each fixed amount of treatment, and work is performed in the closed preheat treatment apparatus. I do. In this case, the basket may not be used in the heat treatment chamber 4, and after the treated waste is taken out from the heat treatment chamber 4, it may be sieved or the like for separation, which will be described later. When the temperature in the heat treatment chamber 4 is raised to about 500° C. while air is introduced from the air inlet 5, the organic substances in the waste 1 are decomposed by the thermal activation (TASC) effect of semiconductors, and low-molecular gases are generated. state and head to the discharge port 6. In the heat treatment chamber 4, the waste is surrounded by an air-permeable structure 7 supporting an oxide semiconductor, and is heated to a temperature higher than the temperature at which a large amount of holes and electrons are generated by interband transition of the oxide semiconductor. Then, the TASC effect purifies the gas along the gas flow 8 towards the outlet 6, and the odor is almost completely removed. Furthermore, a VOC purifying device 10 having a structure 9 supporting an oxide semiconductor and having air permeability is connected to an exhaust port 6 of the heat treatment chamber 4. The gas passing through the VOC purifier 10 is decomposed into water and carbon dioxide, the odor is completely removed and only harmless gas is released into the atmosphere. The most stable Cr ₂ O ₃ (melting point: 2200° C.) is preferably used as the oxide semiconductor supported by the structures 7 and 9 having air permeability.

Here, the phenomenon occurring in the process flow described above will be described for a representative waste material. First, considering "various polymer composite materials" (not including chlorine and sulfur components) based on "semiconductor thermal activation" technology (TASC technology) using iron oxide (α-Fe ₂ O ₃ : hematite) (i) , the polymer is reduced to small molecules by the TASC method, combusted into water and carbon dioxide gas, and the inorganic filler contained in the composite material becomes a powdery residue. In the plastic composite material (ii) containing chlorine and sulfur as components, α-Fe ₂ O ₃ causes TASC decomposition of chlorine-based or sulfur-based polymers. Simultaneously with the decomposition, chlorine and sulfur are liberated, but they immediately react with α-Fe ₂ O ₃ to form FeCl ₂ , FeCl ₃ , FeS, FeS ₂ , etc., and are fixed as solid powder and scattered. No. The same applies to PVC electric wires and rubber tires. Any woven glass fibers or metals that may have been incorporated into the polymer as reinforcement remain intact. In addition, the Si component becomes white SiO ₂ and becomes a residue.
Waste often contains at least one of sulfur, halogen, and silicon as a component. For example, waste electric wires use polyvinyl chloride as the polyethylene coating material and contain a considerable amount of flame retardant (halogen-based). There are also composite compounds of PPS (polyphenylene sulfide) polymers containing sulfur. Hematite is activated at 500° C., and first decomposes a complex compound. At this point, when chlorine and sulfur spout out, hematite is decomposed to form iron chloride (FeCl ₂ , FeCl ₃ ) and iron sulfide (FeS, FeS ₂ ), leaving a black residue as a solid. In other words, since chlorine and sulfur do not scatter outside, they do not cause environmental problems. Next is the separation process. Considering the above residues, there are two types: powdered residues and bulky electric wires, woven fabrics and metals that do not change their shape much. Therefore, after the heat treatment, if the stainless steel basket is used like a coarse sieve (for example, a hole diameter of 5-15 mm) and the basket is vibrated to drop the powdered residue from the gaps in the mesh, Organic substances, sulfur, halogens, and silicon do not remain, and it is possible to easily separate fixed inorganic substances such as electric wires, metal pieces, and woven fabrics in the sieve, and to easily recover valuable metals. can. This is the gist of this application. The TASC process is capable of completely decomposing the polymer, leaving no charred polymer left in the sieve. However, when a polymer composite compound is subjected to TASC treatment, only the polymer is removed, and the remaining inorganic filling is not immediately powdered, but remains in the cage (although it is very brittle). often remain in In that case, for example, when lightly crushed with a wooden pestle (pestle), it crumbles easily, is immediately pulverized and crushed, and falls through a hole in the basket. In this way, when the fixed inorganic matter, which is the fixed inorganic matter remaining in the basket, which is a processing container, contains an inorganic filler that is larger than the hole diameter of the basket, crushing with a pestle or the like is also used. It is desirable to Crushing may be performed at any time before, during, or after applying vibration.
As described above, this method is a problem disposal method that takes advantage of the current disposal method that produces a large amount of bulky waste.
Further, the coarseness of the mesh of the above-mentioned stainless steel cage or sieve, ie, the hole diameter, mainly depends on the length of the electric wire waste and the size of the repeatedly beaten metal waste. The diameter of the eye or the length of one side of the eye is preferably in the range of 1 mm to 30 mm. If the hole diameter is 1 mm or more, it is possible to separate the residue by dropping it through the hole of the basket, but for easier separation, the hole diameter is preferably 5 mm or more. If the hole diameter is 30 mm or less, most of the fixed inorganic substance remains in the cage, but the hole diameter is preferably 15 mm or less to prevent the fixed inorganic substance from dropping more completely. Furthermore, as the mesh becomes larger, the basket is more likely to be distorted (although it depends on the plate thickness of the basket). However, since the shape and size vary depending on the dust, the diameter of the hole may be appropriately selected within the above range.

FIG. 2 shows the waste 1, which is a "waste plastic/metal scrap" mixture of about 5×10×2 mm in size and weighs about 100 g. Clear or white plastic is present in the center, and a piece of metal can be seen in the lower right. FIG. 3 is a photograph of a sample in which the dust is coated with hematite, which is the oxide semiconductor 2 . The hematite coating was prepared by immersing the dirt in a polymer-binder hematite dispersion for 1-2 seconds and then drying in air at 80° C. for 30 minutes. Dust 1 coated with hematite 2 is placed in a stainless steel basket 3 having mesh holes with a hole diameter of 1 mm, and an electric furnace (the inner wall of the electric furnace is lined with a catalyst-supporting honeycomb 7) in air for 30 minutes at 500°C. 4 heat treated. After the treatment, the stainless steel basket 3 is shaken to vibrate, and then the white solid residue (CaCO ₃ ) remaining in the basket 3 is lightly crushed with a wooden pestle [(pestle: mortar)] and immediately pulverized. It turned into dust, and the dust fell from the hole. FIG. 4 shows the fallen matter (inorganic residue: upper part) recovered after treatment and the valuable metal (lower part) recovered from the fixed inorganic matter remaining in the basket 3 side by side. The residue shown in FIG. 4 is the total residue. The weight reduction of garbage was about 85%.
The electric furnace 4 and the external VOC purification device 10 used for the decomposition treatment are as shown in FIG. The inner wall of the heat treatment chamber 4, which is an electric furnace, is covered with a catalyst-carrying honeycomb, which is a structure 7 having air permeability, and is shaped like a honeycomb box. In the hearth, the "waste plastic/metal" waste 1 coated with hematite 2 as a catalyst is placed in a stainless steel basket 3 which is heated to 400-500° C. under air. Only organic substances are decomposed by TASC, leaving only fixed inorganic substances such as metal scraps and residues. As the "waste plastic/metal waste" garbage is decomposed, the odor is first decomposed by the hematite coating material, and the odor progresses to a certain degree of small molecularization. At the same time, when chlorine and sulfur are liberated from the decomposition product, they react with hematite to form FeCl ₂ /FeCl ₃ , FeS/FeS ₂ and the like, respectively, and remain in the hearth. Gases such as odors are chopped into small molecules by the Cr ₂ O ₃ catalyst of the honeycomb wall 7 and decomposed into carbon dioxide gas and water. Furthermore, at the stage of leaving the electric furnace, the gas with a large molecular weight is detoxified by a TASC type VOC purifier 10 (set temperature: 500° C.) equipped with a breathable structure 9 supporting Cr ₂ O ₃ . be.

A rectangular parallelepiped basket 3 was made from a stainless steel mesh having a mesh of 15 mm square, and the same TASC treatment as in Example 1 was performed. When the remaining solid residue was lightly crushed, it immediately crumbled and fell out of the hole. No electric wires, metal pieces, woven fabrics, etc. were observed to fall. FIG. 5 shows the collected residue powder (upper part) and the residue left in the basket (lower part) side by side. These are total residues. Sheets of glass fibers that were embedded in the Glass-fiber Reinforced Plastic (GFRP) are observed as residue in the stainless steel cage. The waste reduction rate was 93%.

A group of 100 g of garbage 1 was treated under the same conditions as in Example 1 above, and a good sorting treatment was achieved. A 93% reduction in total weight was observed. Many of the fallen powders were slightly blackish, and they were iron compounds composed of chlorine and sulfur. Also, most of the residue in the cage was electric wires.

120 g of dust 1 was placed in a stainless steel box 3 with a punching metal (made of stainless steel) having a hole diameter of 25 mm at the bottom, and TASC treatment was performed under the same conditions as in Example 1. The powdery residue that fell and the residue such as metal in the box were well separated. However, when the box 3 was vibrated, the remaining electric wire did not drop, but a metal piece of about 20 mm was found to drop.

According to the present invention, valuable metals can be recovered efficiently and inexpensively from the waste, which is a mixture. Therefore, a safe recovery method and recovery apparatus can be provided without polluting the environment, and the industrial applicability is great.

1 Waste 2 Oxide Semiconductor 3 Processing Container 4 Heat Treatment Chamber 5 Air Inlet 6 Outlet 7 Breathable Structure 8 Gas Flow 9 Breathable Structure 10 VOC Cleaner

Claims (10)

A method for treating inorganic/organic mixed waste comprising a polymer or polymer composite compound containing at least one of sulfur, halogen, and silicon as a component, and metal pieces, etc., wherein the surface of the waste is coated with an oxide semiconductor. a step of storing the waste coated with the oxide in a processing container having a large number of holes having a hole diameter of 1 mm or more and 30 mm or less on the bottom surface and placing the waste in a heat treatment chamber; At a temperature at which a large amount of holes and electrons are generated by interband transition of the oxide semiconductor, the oxidizing power of the holes is used to decompose the organic matter in the waste into water and carbon dioxide, and A step of capturing the sulfur component contained in the waste as a metal sulfide, the halogen component as a metal halide, and the silicon component as a silicon oxide in the residue; a step of separating the residue from the processing container by dropping the residue through a hole in the processing container; and a step of recovering valuable metals from fixed inorganic substances remaining in the processing container. Processing method. The separating step includes a step of crushing fixed inorganic substances remaining in the processing container before, during, or after applying the vibration to the processing container. The method for treating mixed inorganic-organic waste according to claim 1 . 3. The method for treating mixed inorganic-organic waste according to claim 1 , wherein the oxide semiconductor is iron oxide (α-Fe ₂ O ₃ ). 4. The method for treating mixed inorganic-organic waste according to any one of claims 1 to 3 , wherein the hole diameter is 5 mm or more and 15 mm or less. A treatment apparatus for mixed inorganic/organic wastes comprising polymers or polymer composite compounds containing at least one of sulfur, halogen, and silicon, and metal pieces, etc., wherein the surface of the wastes is coated with an oxide semiconductor. a processing container having a bottom surface with a large number of holes having a diameter of 1 mm or more and 30 mm or less for storing the waste coated with the oxide; and a heat processing chamber having an air supply mechanism for supplying air, By heating the processing container installed in the heat processing chamber to a temperature higher than a temperature at which a large amount of holes and electrons are generated by interband transition of the oxide semiconductor, the oxidizing power of the holes is increased in the presence of oxygen. is used to decompose the organic matter in the waste into water and carbon dioxide, the sulfur component contained in the waste is changed to metal sulfide, the halogen component is changed to metal halide, and the silicon component is changed to silicon Valuable metals are separated from the processing container by being trapped in the residue as oxides, vibrating the processing container and causing the residue to fall through a hole in the bottom of the processing container, and remaining in the processing container from fixed inorganic substances. A treatment apparatus for mixed waste of inorganic and organic substances, characterized in that is recovered. 6. The method according to claim 5 , wherein the fixed inorganic matter remaining in the processing container is pulverized before, during, or after the vibration is applied to the processing container. Equipment for processing mixed inorganic and organic waste. 7. The apparatus for treating mixed inorganic-organic waste according to claim 5 , wherein the oxide semiconductor is iron oxide (α-Fe ₂ O ₃ ). 8. The apparatus for treating mixed inorganic-organic waste according to any one of claims 5 to 7, wherein the hole diameter is 5 mm or more and 15 mm or less. The heat treatment chamber has an exhaust port, and a VOC purifier having an air-permeable structure supporting an oxide semiconductor is connected to the exhaust port, and the structure is an interband transition of the oxide semiconductor. By being heated to a temperature higher than the temperature at which a large amount of holes and electrons are generated, the gas is exhausted from the heat treatment chamber and passes through the VOC purifier using the oxidizing power of the holes in the presence of oxygen. 9. An apparatus for treating mixed inorganic-organic waste according to any one of claims 5 to 8, wherein the waste is purified into a harmless gas. The waste placed in the heat treatment chamber is surrounded by an air-permeable structure that supports an oxide semiconductor. 4. Purifying the gas discharged from the waste using the oxidizing power of the holes in the presence of oxygen by heating to a temperature higher than the temperature at which holes and electrons are generated. 10. The apparatus for treating mixed inorganic/organic waste according to any one of 5 to 9.

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