JPH10235319A - Treatment of chlorine-containing waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste treatment method facilitating the detoxification and effective utilization of the gas and residue from a combustion furnace by performing dechlorination as pretreatment. SOLUTION: Chlorine-containing waste is pyrolyzed and dechlorinated and alkali metals and a hydrocarbon decomposing catalyst are added to this treated waste to gasify and burn the same to perform detoxification treatment and, further, fly ash discharged from a combustion furnace 8 is heated to high temp. to be subjected to melt treatment. By this constitution, the amt. of the waste is still more reduced and, in the fly ash heating and melting treatment process, the molten matter after melting is stepwise cooled to separate and recover valuable metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to NaCl, MgC
l ₂ A general method of treating waste such as general garbage discharged from homes containing an inorganic chlorine compound such as vinyl chloride, a plastic mixture containing a plastic containing chlorine such as vinyl chloride, a plastic shredder dust containing a plastic containing chlorine or an inorganic component, etc. The present invention relates to a method for treating waste, which does not generate harmful organic chlorine compounds such as dioxins, and can further reduce the amount of waste such as gasification residues and combustion ash.

[0002]

2. Description of the Related Art In recent years, a large amount of waste containing plastic mixtures and inorganic components including chlorine-containing plastics such as polyvinyl chloride and polyvinylidene chloride has been discharged, and the amount of waste has been increasing steadily. At present, most of such waste is incinerated or landfilled. In the case of incineration, harmful substances such as hydrogen chloride and dioxins generated during incineration may be released to the atmosphere as they are. In addition, in the case of landfill disposal, resources are lost because the effective components in the waste are not used. Thus, it has been proposed to thermally decompose these wastes to recover the effective components therein.

[0003]

However, a large amount of chlorine compounds such as hydrogen chloride and chlorine gas is generated by pyrolysis, gasification or combustion of plastics containing chlorine in wastes.
This not only causes great pollution, but also causes corrosion of the pyrolysis, gasification or combustion furnace. In order to remove chlorine compounds by pre-treating these wastes, a method has been proposed in which thermal decomposition is performed in a decomposition tank by indirect heating using a heating medium or a heater. With this method, it is difficult to uniformly heat the solid inside the cracking furnace, so in the case of thermoplastic plastics in particular, the parts that have been softened and melted by local heating are fused together to form a lump, and undecomposed hydrogen chloride is mixed into the molten plastic. This hydrogen chloride cannot be completely removed.

Further, chlorine compounds (CaCl ₂ , NaCl, KCl, etc.) with alkali metals are obtained by adding an alkali metal compound such as Ca, Na, K or the like to these wastes and thermally decomposing, gasifying or burning them. As a method of removing it. Ca (OH) ₂ + 2HCl → CaCl ₂ + H ₂ O (1) CaCO ₃ + 2HCl → CaCl ₂ + H ₂ O + CO ₂ (2) NaOH + HCl → NaCl + H ₂ O (3) KOH + HCl → KCl + H ₂ O ...... (4)

However, in order to react the entire amount of hydrogen chloride HCl generated from the waste with the alkali metal to separate it as a chlorine compound, in consideration of the reaction rate, conventionally, about four times equivalent or more of the alkali metal is used. Was added. As a result, a large amount of residue has been discharged due to the addition of excess alkali metals.

Further, in this method, after pre-treating a waste containing a metal such as car shredder dust and the like, a residue containing a by-product chlorine compound and a metal is again treated in a melting furnace or the like to recover the metal. These chlorine compounds are about 750 ° C
It is in a molten state at the above high temperature, and this scatters as a mist, and comes into contact with metal to cause corrosion. In particular, in the method of burning waste containing a large amount of chlorine as it is and adding an alkali metal compound to the waste, the amount of chlorine compound produced as a by-product increases, and the problem of corrosion due to the melt increases. Furthermore, since plastics contain trace amounts of heavy metals as plasticizers, stabilizers, or paints, there is a problem in disposing of these combustion residues as they are.

In view of the above technical problems, the present invention makes it possible to easily decontaminate and effectively utilize gases and residues generated from a combustion furnace by performing dechlorination as a pretreatment. It is an object of the present invention to provide a waste disposal method. It is an object of the present invention to provide a method for treating waste in which the amount of waste is further reduced as compared with the invention described in claim 1. A fourth object of the present invention is to provide a method for treating wastes in which valuable metals can be easily separated and recovered from fly ash according to the second or third aspect, thereby further reducing pollution. It is an object of the present invention to provide a method for treating waste which promotes the decomposition of hydrocarbons in the gasification furnace or the combustion furnace according to the first aspect and further improves the combustion efficiency. .

[0008]

Means for Solving the Problems In order to solve the problems, the present inventors have previously described a method for treating waste containing chlorine-containing plastics by treating the waste with a high-temperature heat-resistant material such as sand. After mixing with the particles and putting them into a pyrolysis furnace, which are thermally decomposed to about 250 to 350 ° C, waste that removes hydrogen chloride generated by adding an alkaline substance when gasifying or burning residual solids An article processing method was proposed.
(Reference number 9504456A, filed on February 23, 1996) The present invention is a further development of the invention according to the prior application, and the gist thereof is as follows.

In the thermal decomposition and dechlorination step, about 80% by weight or more of the amount of chlorine contained in the waste is converted into hydrogen chloride by dechlorination.
Because of the separation, only about 20% by weight or less of the chlorine contained in the solid after the dechlorination treatment remains.
Since it is sufficient to add an alkali metal to the residual chlorine amount, the amount of addition is about と な り or less of the conventional method, and as a result, the excess alkali metal amount is reduced. That is, the amount of generated waste is reduced. On the other hand, when heating and melting the fly ash or the bottom residue generated by gasification or combustion, the composition of the ash affects the melting temperature (see FIG. 2). For example, the melting point when CaO is 100% is 2,
At 570 ° C. and 100% SiO ₂ , 1,
723 ° C., but CaO / SiO ₂ as shown in FIG.
= 1 (weight ratio), it melts at 1,400-1,500 ° C. Therefore, the melting treatment can be performed at a low temperature by reducing the amount of the alkali metal added.

[0010] In addition, the waste contains a component which is easily converted into an aromatic compound by further polycondensation of the hydrocarbon decomposed by the heat treatment. The aromatic compound reacts with a small amount of chlorine remaining in the solid after the thermal decomposition and dechlorination treatment to generate a harmful organic chlorine compound. Therefore, by adding a catalyst having an effect of promoting the decomposition of hydrocarbons in the waste to the gasification furnace or the combustion furnace, it is possible to prevent the by-product of the organic chlorine compound. in this case,
The same effect can be obtained by adding the catalyst even if the catalyst is mixed and supplied with the raw material waste before the thermal decomposition and dechlorination step. Examples of the catalyst include Fe, Ag, Pb, Pt, Ce, Th,
S, Pd, Cu, K, Mo, Co, Mn, Cr, Ni,
A substance containing components such as Br, V, Bi, and Al has a large effect.

According to the first aspect of the present invention, a waste containing chlorine is heated by a heating medium particle such as sand or a heating gas to thermally decompose and dechlorinate the waste. By adding an alkaline substance to a gas-decomposed solid and gasifying or burning it in a gasification furnace or a combustion furnace, pollution-free treatment is possible and the amount of waste generated is reduced. The invention according to claim 2 is characterized in that fly ash discharged from the gasification furnace or the combustion furnace is heated and melted at a high temperature to further reduce the amount of waste. According to a third aspect of the present invention, in the fly ash heating and melting process according to the second aspect, residue (furnace ash) separated and discharged from the bottom of a gasification furnace or a combustion furnace is converted into the fly ash. Mix and heat
It is characterized by melting.

According to a fourth aspect of the present invention, in the heating and melting process of fly ash according to the second or third aspect, the molten material after melting is cooled stepwise to separate and recover valuable metals. And According to a fifth aspect of the present invention, in the method for treating a waste containing chlorine according to the first aspect, a catalyst having an effect of promoting the decomposition of hydrocarbons in the waste is added to the gasification furnace or the combustion furnace. It is characterized by.

As will be understood from the above description, the present invention provides a method of pyrolyzing and dechlorinating a waste containing chlorine, followed by adding a catalyst for decomposing alkali metals and hydrocarbons to gasify and burn. Is a pollution-free method. In this case, as waste containing chlorine, (1) garbage discharged from households mixed with inorganic chlorine compounds such as NaCl and MgCl ₂ and plastics containing chlorine. (2) Plastic mixtures containing plastics containing chlorine, such as vinyl chloride. (3) A so-called car shredder dust (hereinafter referred to as C) mainly composed of plastic after removing metals from an automobile.
Abbreviated as SD. ) Etc., but are not limited thereto.

[0014] General garbage discharged from homes contains about 1 to 3 wt% of chlorine. In addition, about 2 to 5 wt% of chlorine is contained in plastic waste discharged from households that are separately collected in some areas.
Table 1 shows the types of CSD components, and Table 2 shows the breakdown of the plastics that account for the majority in Table 1. As is clear from Table 2, CSD uses polyvinyl chloride (PVC) as an instrumentation wire, and contains about 0.5 to 5 wt% of chlorine in CSD.

[0015]

[Table 1]

[0016]

[Table 2]

FIG. 3 shows the temperature and the rate of weight loss when various plastics are thermally decomposed.
(5) P787 (1973)｝. Thermoplastics generally soften and melt at about 120-230 [deg.] C. and then thermally decompose at higher temperatures. The thermosetting resin is thermally decomposed by heating without being softened or melted. Examples of plastics containing chlorine include polyvinyl chloride (PVC) and polyvinylidene chloride. In these chlorine-containing plastics, most of the chlorine is desorbed as hydrogen chloride in the region of about 170 ° C. to 350 ° C., and when the temperature becomes high, thermal decomposition of other components proceeds. Hereinafter, a model formula of chlorine desorption is shown in the formula [1].

[0018]

Embedded image

FIG. 4 shows the removal of HC from PVC (polyvinyl chloride).
1 indicates speed. ｛Mitsubishi Heavy Industries technical report, 10 (5) P787
(1973)｝. From this figure, it is almost 100
% DeHCl, but requires a long residence time of tens of minutes.

As is apparent from FIG. 3, the plastic mixture rapidly starts to decompose at about 250 ° C.
Most decompose by about 500 ° C. Therefore, the present invention firstly divides the crushed waste into a temperature range (about 250 to 350 ° C.) in which the thermal decomposition rate of hydrocarbons in plastic is as low as possible and the thermal decomposition rate of chlorine Cl is high. To decompose and separate chlorine at a high dechlorination rate of 80 to 90 wt% or more of the initial chlorine content. In this case, the residual solid mainly composed of a hydrocarbon component contains about 20 wt% chlorine. In order to fix HCl generated when the residual solid is gasified or burned in the next step,
Add alkali metals. This alkali metal and HC
l produces a chlorine compound by the reaction of the above formulas (1) to (4) and the like, and chlorine Cl is immobilized. In this case, the alkali metal is preferably added in an amount equivalent to 1.5 to 2 times the chlorine content.

If the waste contains sulfur S component, for example, the following reaction (5) occurs,
It is necessary to add a reaction equivalent of the alkali metal added to the S content in the waste. SO ₃ + Ca (OH) ₂ → CaSO ₄ + H ₂ (5)

In adding the alkali metals,
The following process is important. (1) Sufficient mixing with residual solids after dechlorination is important. (2) The smaller the particle size of the alkali metal, the higher the reaction rate. Therefore, a method of supplying alkali metals in a water slurry is preferable from the viewpoint of improving the reaction rate. The supply of the alkali metals may be directly supplied to the gasification furnace or the combustion furnace, but for the above-described reason, it is better to treat the residual solid after the dechlorination treatment with the gasification furnace or the combustion furnace after the mixing treatment. preferable.

By the way, the waste contains a component which is easily converted to an aromatic compound by further polycondensing hydrocarbons after decomposing and desorbing chlorine by thermal decomposition and dechlorination. The aromatic compound reacts with a small amount of chlorine remaining in the solid after the thermal decomposition and dechlorination treatment to generate a harmful organic chlorine compound. Therefore, it is necessary to add a catalyst having an effect of promoting the decomposition of these hydrocarbon compounds to the above-mentioned gasification furnace or combustion furnace, thereby preventing by-products of the organic chlorine compounds. The catalyst includes Fe, A
g, Pb, Pt, Ce, Th, S, Pd, Cu, K, M
A substance containing components such as o, Co, Mn, Cr, Ni, Br, V, Bi, and Al has a large effect. For the decomposition of aromatic hydrocarbons, in particular, V, Mo, P, Sn, Al, Co,
The catalytic effect of Mn and the like is large. In this case, the addition of the catalyst
The same effect can be obtained by mixing and supplying the raw material waste before the thermal decomposition and dechlorination step.

The solid substance after the dechlorination treatment (thermal decomposition) by the above method is led to the next gasification or combustion step, and the organic matter (hydrocarbon) is gasified or combusted. Fly ash generated in the gasification or combustion process is separated from the exhaust gas and melted. Since the fly ash contains an alkali metal component, it melts in a temperature range of about 1,200 to 1,400 ° C. From the bottom of the gasifier or combustion furnace,
Metal oxides and glass components are discharged. Among metals,
Because the chlorine compound is in a small amount, the bottom ash discharged from the bottom of the gasification furnace or the combustion furnace is mixed with the fly ash and melted, and the metals are separated and recovered using the difference in melting points, It can be reused as valuables.

In the method in which the heating medium is circulated in the thermal decomposition and dechlorination step, since the heating medium is constantly moving and is present between the wastes, the state of fusion between the wastes, coking and the like is prevented. can do. In addition, since the substance that adheres to the wall surface of the thermal decomposition apparatus is constantly scraped, coking on the wall surface can be prevented at the same time. The structure of the pyrolysis furnace is provided with a mechanism to stir and mix the mixture in the pyrolysis vessel in order to improve the heat exchange performance between the heating medium and the plastic, but the vessel itself rotates like a rotary kiln type Some have stirring / mixing ability. Further, it is also possible to carry out a thermal decomposition treatment by indirect heating by flowing the heating medium through the outer cylinder in a double structure.

According to the above method, most of the dechlorination is performed as a pretreatment, so that the gas generated in the gasification or combustion step contains almost no chlorine, and only a small amount of chloride remains in the residue. Therefore, pollution-free and effective utilization of generated gas and residue is facilitated.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. It's just

FIG. 1 shows a waste disposal apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a hopper for charging waste, 2 is a pyrolysis furnace composed of, for example, a rotary kiln for mixing waste and heating medium particles, 4 is a residual solid matter generated in the pyrolysis furnace 2 and heating medium particles. A mixing tank 8 for adding and mixing an alkali metal and a catalyst, and 8 for removing residual solids from the mixing tank 4 mixed with an alkali metal or a catalyst by about 700.
A fluidized bed combustion furnace for gasification or combustion at a temperature of up to 1,000 ° C .; 11 a heat exchanger for recovering heat of gasification product gas or combustion exhaust gas from the fluidized bed combustion furnace 8;
Is a cyclone or dust collector that collects and separates scattered particles in the gasification product gas or flue gas, 13 is a separator that separates the collected solid particles into fly ash particles and heat medium particles, 1
Reference numeral 4 denotes an exhaust gas processing step. Reference numeral 23 denotes an absorption reaction tower that absorbs pyrolysis gas mainly composed of hydrogen chloride generated in the pyrolysis furnace 2, and reference numeral 34 denotes a heating and melting furnace for fly ash collected by the cyclone 12.

In this configuration, waste containing chlorine-containing plastics such as polyvinyl chloride and polyvinylidene chloride is supplied from a hopper 1 to a rotary kiln-type pyrolysis furnace 2, while heating medium particles made of sand or the like are supplied. About 40
When the waste and the heating medium particles are respectively supplied to the pyrolysis furnace 2 through the high-temperature line 21 at 0 ° C., the waste and the heating medium particles are mixed by rotation of the kiln in the pyrolysis furnace 2, whereby the waste is reduced to about 250 to Heated to 350 ° C. The heated waste starts pyrolysis, and pyrolysis gas mainly composed of hydrogen chloride generated by the pyrolysis is taken out from a pyrolysis furnace 2 through an extraction line 2.
After passing through 2, the gas is sent to the absorption reaction tower 23.

On the other hand, residual solids and heating medium particles generated by the softening or melting of the waste in the pyrolysis furnace 2 are supplied from the pyrolysis furnace 2 to the mixing tank 4 via the line 3. Here, alkali metal from line 5 and line 6
Is added and mixed with the residual solids. The residual solid mixed with the alkali metals or the catalyst is supplied to a gasification furnace or a combustion furnace 8 through a line 7 and is supplied by air or oxygen supplied from a line 9 or a mixed gas of air or oxygen and steam. , About 700 to 1,000
It is gasified or burned at a temperature of 0 ° C. The gasification product gas or flue gas passes through line 10 and passes through heat exchanger 1
After heat recovery in step 1, the flying particles are collected and separated from the exhaust gas by a cyclone or a dust collector 12.

The exhaust gas from which the scattered particles have been collected and separated is processed in the gas processing step 14 via the line 37 and then discharged from the line 15. Cyclone or dust collector 12
The scattered particles collected by the above are separated into heat medium particles by the separator 13, and the fly ash is melted in the melting furnace 34 through the line 35 and then discharged from the line 36. The heating medium particles separated in the separator 13 are withdrawn from a line 39 and a part is returned to the gasification furnace or the combustion furnace 8 from a line 38,
Most is recycled from the line 21 to the pyrolysis and dechlorination furnace 2. The bottom ash of the gasification or combustion furnace 8 is withdrawn from the line 31 and discharged through the line 32 or supplied to the melting process 34 through the line 33.

[0032]

Next, an embodiment of the apparatus will be described. Pre-ground CSD 50.5K having the composition of Table 1 and Table 2
g / h (dry standard) 5K of sand (average particle size 200μm)
g / h (about 10 wt%), and the mixture was supplied from a hopper 1 to a rotary kiln type pyrolysis furnace 2. In a rotary kiln, a gas generated by burning propane gas in a hot blast stove is brought into direct contact with the CSD in countercurrent to heat it. The operating conditions at this time are hot air generator outlet gas temperatures 520 to 55.
0 ° C, kiln wall inlet temperature 200-220 ° C, outlet temperature 290-330 ° C, average residence time in the kiln 25 min
And Thermoplastics such as polyvinyl chloride
Generally, it softens and melts at about 120 to 230 ° C, and then thermally decomposes at a high temperature thereafter. The thermosetting resin is thermally decomposed by heating without being softened or melted. Plastics containing chlorine such as polyvinyl chloride and polyvinylidene chloride are about 1
Most of the chlorine is decomposed and desorbed as hydrogen chloride HCl in the range of 70 to 350 ° C., and thereafter, when the temperature becomes high, thermal decomposition of other components proceeds. As described above, the waste containing plastics rapidly starts to decompose at about 250 ° C.
Most decompose by 0 ° C.

Therefore, in this embodiment, the decomposition and decomposition of hydrogen chloride in the region where the rate of thermal decomposition of plastic is as low as possible
In order to promote the separation and to separate the separated hydrogen chloride at a high concentration, the temperature of the waste containing plastic is about 250-35.
The operating temperature inside the rotary kiln was adjusted to 0 ° C. The amount of gas generated from the rotary kiln (pyrolysis furnace) 2 was 6.2 kg / h for moisture and 1.2 kg / h for HCl.
h, hydrocarbon gas was 0.9 kg / h. Further, the residual solid matter after the pyrolysis discharged from the rotary kiln 2 is obtained by uniformly mixing the added sand and the sand or metal originally contained in the waste with the softened and molten plastic, and 5 to 30 mm. Pellets.

Further, a rotary kiln (pyrolysis furnace) 2
When the inner wall was observed, almost no plastic fusion or caulking of the wall was observed. The pyrolysis gas mainly composed of hydrogen chloride discharged from the rotary kiln (pyrolysis furnace) 2 is sent from a line 22 to an absorption reaction tower 23,
Absorbed in wash water. On the other hand, the extracted residual solids are
The mixture was supplied to the mixing tank 4. Slaked lime Ca (OH) ₂ as an alkali metal and iron oxide as a catalyst were added to the mixing tank 4 and uniformly mixed with the residual solid. The mixing amount of the additives was as follows. That is, assuming the undecomposed rate of chlorine in the residual solid to be 10% of the initial chlorine content of 3.5 wt /%, 0.22 kg / h of 1.5 times equivalent of the chlorine amount was added. Further, 0.02 kg / h of an iron-based catalyst was added.

In place of slaked lime, finely ground limestone CaCO ₃ can also be used. However, in this case, since limestone is once decomposed into CaO, (CaCO ₃ → CaO + CO ₂ ) The temperature inside the combustion furnace 8 is higher than the decomposition temperature of limestone, for example, 900 to
It is necessary to raise the temperature to 1,100 ° C., and the reactivity with HCl and SO ₂ is lower than when slaked lime is used.

Next, the mixture was supplied to a circulating fluidized bed type combustion furnace 8 through a line 7, where the mixture was burned at 860 to 910 ° C. Air was supplied from the bottom of the combustion furnace 8, and the mixture sent from the line 7 was burned while flowing. At this time, acidic gases such as hydrogen chloride and sulfur dioxide generated by the combustion reacted with the added Ca (OH) ₂ to produce CaCl ₂ and CaSO ₄ . Ca (OH) ₂ + 2HCl → CaCl ₂ + 2H ₂ O Ca (OH) ₂ + SO ₂ + (1/2) O ₂ → CaSO ₄ + H ₂ O

On the other hand, the concentrations of HCl and SO ₂ in the combustion exhaust gas were both 15 ppm or less. CaCl ₂ and CaSO ₄ generated in the combustion furnace 8 were collected by the cyclone 12 as fly ash together with part of the sand and metal powder. Of the collected fly ash, sand of 100 μm or more is
Recycled from 1 was used. On the other hand, when a heavy metal in a solid material of 100 μm or less was subjected to a dissolution test in accordance with the dissolution test method for hazardous metals and the like notified by the Environment Agency, the results shown in Table 3 below were obtained.

[0038]

[Table 3]

The dioxin concentration in the solid was analyzed to be 0.05 ng-TEQ / Nm ³ or less. Next, the solid was put into a heating and melting furnace 34 for processing, and as a result, the whole was completely melted at 1,350 ° C. From the above test results, the following effects were confirmed as the effects of this example. A) The amount of alkali metal added was reduced to 1/10 of the conventional amount by the thermal decomposition and dechlorination step. As a result, the amount of generated ash was reduced. B) Since the metals in the ash discharged from the furnace bottom of the combustion furnace do not contain chlorides, they can be reused as valuable metals. C) With the addition of the combustion catalyst, the amount of dioxins produced fell below the guidelines of the Ministry of Health and Welfare. D) From the above results, it was confirmed that the present invention is very effective for treating waste containing high concentration of chlorine.

Next, in order to confirm the effect of the present invention, FIG.
The following comparative experiments were performed using the apparatus shown in FIG. That is, the whole pulverized CSD was supplied to the fluidized bed combustion furnace without passing through the pyrolysis furnace 2 and was burned at 850 ° C. As a result, the combustion residue discharged from the bottom of the combustion furnace contains chlorine at 2.
1 wt%, and chlorine reacted with metal components by combustion to produce chloride. It is assumed that chloride was generated by the following reaction. FeO + 2HCl → FeCl ₂ + H ₂ O ZnO + 2HCl → ZnCl ₂ + H ₂ O CaO + 2HCl → CaCl ₂ + H ₂ O CdO + 2HCl → CdCl ₂ + H ₂ O As a result, the metal component as a chloride is Difficult to reuse. The harmful components in the combustion exhaust gas were as follows. HCl concentration: 1,955 ppm SO _x concentration: 830 ppm Dioxin concentration: 5,360 ng-TEQ / N
m ³ (Ministry of Health and Welfare guidelines 0.1 ng-TEQ / Nm ³ )

[0041]

As described above, according to the first aspect of the present invention, by performing the dechlorination as a pretreatment, the gas generated in the gasification or combustion step contains almost no chlorine and further contains the residue. Also, since only a small amount of chloride remains, it is easy to make the generated gas and the residue non-pollution and effective use. The inventions of claims 2 and 3 can further reduce the amount of waste compared to the invention of claim 1. According to the fourth aspect of the invention, valuable metals can be easily separated and recovered from the fly ash according to the second or third aspect, and the pollution can be further reduced. According to the fifth aspect of the present invention, the decomposition of hydrocarbons in the gasification furnace or the combustion furnace according to the first aspect can be promoted, and the combustion efficiency can be further improved.

[Brief description of the drawings]

FIG. 1 shows a waste disposal apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a melting temperature of ash corresponding to a composition ratio of ash (CaO, SiO ₂ , etc.).

FIG. 3 shows the temperature and the weight loss rate when various plastics are thermally decomposed.

FIG. 4 is a time-series graph showing the HCl removal rate of PVC.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hopper 2 Pyrolysis furnace consisting of a rotary kiln 4 Mixing tank 8 Gasification furnace or fluidized bed combustion furnace 11 Heat exchanger 12 Cyclone or dust collector 13 Separator 14 Exhaust gas treatment process 23 Absorption reaction tower 34 Heat melting furnace

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F23G 5/027 ZAB F23J 1/00 B F23J 1/00 B09B 3/00 ZAB 303L

Claims (5)

[Claims] 1. A waste containing chlorine is heated by heating medium particles such as sand or a heating gas to thermally decompose the waste and add an alkaline substance to a solid obtained by decomposing the pyrolysis gas. A method for treating chlorine-containing waste, characterized in that non-polluting treatment is possible and the amount of generated waste is reduced by gasification or combustion in a gasification furnace or a combustion furnace. 2. The method according to claim 1, wherein the fly ash discharged from said gasification furnace or combustion furnace is heated and melted at a high temperature to further reduce the amount of waste. Waste treatment methods, including: 3. The process for heating and melting fly ash according to claim 2, wherein the fly ash is separated from the bottom of a gasification furnace or a combustion furnace.
A method for treating waste containing chlorine, wherein a discharged residue (furnace ash) is mixed with the fly ash and heated and melted. 4. The method of heating fly ash according to claim 2 or 3,
In the melting treatment process, a method for treating waste containing chlorine, characterized in that a molten material after melting is gradually cooled to separate and recover valuable metals. 5. The method for treating waste containing chlorine according to claim 1, wherein a catalyst having an effect of promoting the decomposition of hydrocarbons in the waste is added to the gasification furnace or the combustion furnace.