JPH09323076A - Method of recovering metal from waste plastics/metal laminated body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal recovery method by which only metal is recovered in a nonoxidized, clean state from waste such as packing material, electronic substrates and electric wires in which plastics such as polyester and metal such as aluminum are stacked in a laminated state. SOLUTION: In this metal recovery method, by bringing waste 'i' of a plastics/metal laminated body into direct contact 7 with product gas 'e' of temperature not more than the melting point of the metal and not less than a temperature at which the plastics is thermally decomposed from a gasifying furnace, preferably a fluidized bed gasifying furnace 1, the plastics is removed and the metal is recovered '1'. The contact of the waste 'i' with the product gas 'e' is performed under the oxygen free atmosphere or while feeding oxygen- containing gas, and as the product gas, thermally decomposed gas of solid waste 'a' heated to 450∼700 deg.C from the gasifying furnace 1 is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering metal from waste of a plastic / metal laminate, and particularly to a packaging material and electric wires in which plastics such as polyester and epoxy and metals such as aluminum and steel and copper are laminated. And a method of heat-treating the waste of a plastic-laminated electronic substrate containing a copper foil to recover only the metal in a clean state without being oxidized.

[0002]

2. Description of the Related Art In recent years, with the widespread use of various retort foods, laminated packaging materials such as toothpaste medicine tubes, beverage cans such as beer and juice, food cans, electronic substrates for electronic computers and controllers, container manufacturing and substrate processes. A large amount of waste such as cut pieces is generated in the above, and with the large amount of waste generated after the use of those containers and electronic devices, it is difficult to process the waste. High-grade aluminum is often used for this type of packaging material, and high-grade copper foil is used for electronic substrates, and most of these are currently subjected to landfill disposal. There is a strong demand for effective use. Therefore, if only the plastic component is removed by heat treatment, and the metal is recovered and recycled for use while maintaining a high quality, it will be very effective for effective use of resources or reduction of waste amount. There is an attempt to burn only waste materials such as packaging materials, can materials and substrate materials in which plastics such as polyester and epoxy and aluminum, steel, and copper are laminated in a laminated form to recover only metals such as aluminum. There is a problem that part of the metal is oxidized because it is burned in an oxidizing atmosphere. Further, when a large amount of air is supplied for combustion, since it is a thin foil-shaped metal, it is accompanied by the combustion exhaust gas and rises up, and there is a problem that it is deposited inside the flue and the gas treatment device.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and eliminates waste materials such as packaging materials, can materials, electric wires, and substrate materials in which plastics such as polyester and metals such as aluminum are laminated in a laminated form. An object of the present invention is to provide a metal recovery method capable of recovering only metal in a clean state that is not oxidized.

[0004]

In order to solve the above problems, in the present invention, the waste of the plastic / metal laminate is treated at a temperature below the melting point of the metal and above the temperature at which the plastic is pyrolyzed and gasified. The metal recovery method is characterized in that the plastic content is removed and the metal is recovered by directly contacting with the generated gas from the chemical conversion furnace. In the above method, the direct contact between the waste and the produced gas is performed in an oxygen-free atmosphere or under the supply of an oxygen-containing gas, and the metal is aluminum, steel, copper, or any other metal constituting a laminate. In addition, the gasification furnace can use solid waste as a raw material, and the produced gas can be gas heated to 450 to 700 ° C. from the gasification furnace,
Then, the metal can be recovered by sieving a mixture of the discharged metal and a carbide which is a decomposition product of the plastic. Further, since the produced gas from the gasification furnace which is in direct contact with the plastic / metal laminate contains the gasification decomposition product of plastic, it is preferable to combust it in the combustion furnace in the subsequent stage. In the combustion furnace, 1200-1
It is preferable to combust at 400 ° C., melt ash to form molten slag, and discharge the slag from the bottom of the combustion furnace. Further, as the combustion furnace, it is preferable to use a swirling melting furnace.

[0005]

Next, the present invention will be described in detail.
In the present invention, the plastic / metal laminate waste, for example, the waste of the packaging material, and the product gas from the gasification furnace controlled to a predetermined temperature, preferably the fluidized bed gasification furnace, are directly contacted with each other to produce the plastic. Only the portion is pyrolyzed and gasified, and the remaining metal is recovered in a clean state without being oxidized. Specifically, the plastic thermal decomposition machine installed in the discharge path of the high-temperature product gas from the fluidized bed gasification furnace was used to remove the plastic / metal laminate waste that had been finely cut in advance, with the air cut off. By supplying a fixed amount by, the plastic content is pyrolyzed and gasified in the absence of oxygen to form gas components such as gas / tar and solid carbide particles. The pyrolysis gas generated by the thermal decomposition of plastic is sent to the combustion furnace in the subsequent stage and burned together with the generated gas from the gasification furnace, and the solid carbide particles are discharged out of the system together with the metal foil and then coarsened by sieving. A fine metal foil is separated and recovered from the fine carbide particles.

Alternatively, by supplying air to the plastic thermal decomposition machine, the plastic portion of the shredded plastic / metal laminate waste is partially combusted to be pyrolyzed and gasified, and gas / tar gas is produced. It becomes an ingredient. In this case, the char is gasified into CO or CO ₂ and is hardly mixed in the separated metal. Therefore, only the metal foil is discharged out of the system and collected. When the gasification furnace of the present invention is a fluidized bed furnace, sand such as silica sand and olivine sand, alumina, dolomite, limestone and the like can be used as the fluid medium. In the fluidized bed gasification furnace, air, oxygen-enriched air, or oxygen + steam is appropriately selected and supplied to the gasification furnace, and primary combustion is performed at 450 to 700 ° C. Then, in the present invention, the produced gas obtained by the primary combustion is introduced into a plastic thermal decomposition machine and brought into direct contact with the shredded plastic / metal laminate. For example,
In order to recover aluminum as a metal, the temperature of the generated gas may be set lower than 660 ° C. which is the melting point of aluminum.

Hereinafter, the present invention will be specifically described with reference to the drawings. FIG. 1 is an overall configuration diagram of a combustion device to which the metal recovery method of the present invention is applied. In FIG. 1, 1 is a gasification furnace,
2 is a fluidized bed, 3 is a deaeration damper (quantitative supply, extraction device), 4 is a laminated waste supply, a deaeration damper for discharge,
5 is a vibrating screen, 6 is a sand conveying elevator, 7 is a plastic thermal decomposition machine, 8 is a crushing material feed conveyor, 9 is a vibrating screen,
Reference numeral 10 is a swirl type melting furnace, 11 is a primary combustion chamber, 12 is a secondary combustion chamber, and 13 is a slag separating section. Next, each component of FIG. 1 will be specifically described. 1 is a fluidized bed gasification furnace for treating a large amount of combustible materials other than laminated body waste, and is a fluidized medium from a degassing damper 3 at the bottom of the furnace. Certain sand and coarse incombustibles are continuously discharged, and the discharged sand and coarse incombustibles are supplied to the vibrating screen 5 and separated into fine sand and coarse incombustibles. The separated sand is circulated in the gasification furnace 1 by the sand transport elevator 6.

On the other hand, primary air b is fed from below the fluidized bed gasification furnace 1 to form a fluidized bed 2 of sand.
The combustible material a put in the above is rapidly pyrolyzed and gasified at 450 to 700 ° C. Gas, tar, and carbide are generated with the gasification, and the carbide is finely pulverized by the disturbing motion of the fluidized bed 2 to become char, and is entrained in the generated gas,
It is discharged from the gasification furnace 1. Further, in order to adjust the temperature of the produced gas, the gasification furnace is provided with an inlet for the secondary air c, and when the temperature of the produced gas is low, the secondary air is blown in to partially burn and raise the temperature. be able to.

The produced gas e discharged from the gasification furnace is introduced into the plastic thermal decomposition machine 7. The plastic pyrolyzer 7 contains crushed materials of plastic / metal laminate i.
Is supplied by the degassing damper 4 of the supply device, and is sent by the crushing raw material feed conveyor 8 provided in the thermal decomposition machine 7 while only the plastic component is pyrolyzed and gasified by the heated product gas e introduced. . On the other hand, metal and char are discharged by the degassing damper 4 for extraction.
Coarse metal 1 is separated from the discharged solid containing metal and char by the vibrating screen 9, and is recovered in a recyclable and clean state, and the solid component k containing fine char is introduced into the swirl melting furnace 10. . The introduction into the swirl-type melting furnace 10 can be introduced together with the tertiary air j into the primary combustion chamber. The pyrolysis gas that has been pyrolyzed by the plastic pyrolyzer 7 is introduced into the primary combustion chamber 11 of the swirl melting furnace 10 together with the generated gas e from the fluidized bed gasification furnace. At this time, it is also possible to separate only char f from the generated gas from the gasification furnace 1 and directly introduce it into the primary combustion chamber 11.

The generated gas e and char f supplied to the primary combustion chamber 11 of the swirl-type melting furnace 10 are preheated tertiary air j.
High speed combustion at 1200 to 1400 ° C while mixing in a swirling flow. The combustion is completed in the next secondary combustion chamber 12, and the combustion exhaust gas g is exhausted from the slag separating section 13. The ash contained in the char becomes slag mist due to the high temperature, is captured by the molten slag phase on the furnace wall of the primary combustion chamber 11 by the centrifugal force of the swirling flow, flows down the furnace wall and enters the secondary combustion chamber 12, It is discharged from the bottom of the slag separating part 13. Note that the combustion exhaust gas g exiting the swirl melting furnace 10 is released into the atmosphere through a series of heat recovery devices such as a waste heat boiler, a economizer, and an air preheater. In the above, it is also possible to feed controlled air 15 into the plastic pyrolyzer 7. As a result, the plastic, or the plastic of the laminated waste such as aluminum, is partially burned to accelerate the pyrolysis gasification of the carbide. By supplying the air 15, it becomes possible to achieve smooth and simple plastic pyrolysis gasification process. In the plastic thermal decomposition apparatus 7, the oxygen in the air 15 sent in causes a partial oxidation reaction of the plastic, but since the inside of the layer is kept in a reducing atmosphere, the metal can be taken out without being oxidized.

[0011]

INDUSTRIAL APPLICABILITY In the present invention, a metal laminate of a plastic such as a waste of a packaging material obtained by laminating a plastic such as polyester and a metal such as aluminum in a laminated form, a waste of an electronic substrate, a waste electric wire, etc. It is intended to provide a method for pyrolyzing and gasifying by directly contacting with a medium having a temperature lower than the melting point, and recovering only metal in a clean state that is not oxidized, that is, in a recyclable state. By applying the present invention, it is possible to collect the metal in a state in which the quality of the metal is kept higher than that of the waste of the plastic / metal laminate, which is very effective from the viewpoint of effective use of resources or reduction of the amount of waste dumped.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a combustion device to which a metal recovery method of the present invention is applied.

[Explanation of symbols]

1: Fluidized bed combustion furnace, 2: Fluidized bed part, 3: Degassing damper,
4: Deaeration damper, 5: Vibrating sieve, 6: Sand transport elevator, 7: Plastic thermal decomposition machine, 8: Crushing material feed conveyor, 9: Vibrating sieve, 10: Swirling type melting furnace, 11: Primary combustion chamber, 12 : Secondary combustion chamber, 13: slag separation part, 1
5: air, a: waste, b: primary air, c: secondary air,
d: non-combustible material, e: generated gas, f: char, g: combustion exhaust gas, h: slag, i: laminated waste, j: tertiary air,
k: solid containing char, l: recovered metal,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takio Muramatsu 11-11 Haneda-Asahicho, Ota-ku, Tokyo Inside EBARA CORPORATION

Claims (6)

[Claims] 1. A waste material of a plastic / metal laminate,
A metal recovery method comprising recovering a metal by directly contacting with a generated gas from a gasification furnace at a temperature lower than a melting point of a metal and at a temperature higher than a temperature at which a plastic is pyrolyzed and gasified. 2. The direct contact between the waste and the produced gas is
The metal recovery method according to claim 1, wherein the metal recovery method is carried out under an oxygen-free atmosphere or under an oxygen-containing gas supply. 3. The metal recovery method according to claim 1, wherein the metal is aluminum, steel, copper, or another metal forming a laminated body. 4. The metal recovery method according to claim 1, wherein the gasification furnace uses solid waste as a raw material. 5. The product gas is generated from the gasifier.
The metal recovery method according to any one of claims 1 to 4, wherein the gas is heated to 50 to 700 ° C. 6. The metal recovery method according to claim 1, wherein the recovery of the metal is performed by sieving a mixture of the discharged metal and a decomposition product of the plastic.