JPH11116727A - Method for recovering metal and resin component from metal/plastic composite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means of efficiently processing a metal/plastic composite of, e.g. a scrapped vehicle to realize the recovery and utilization of a metal to thereby reduce the environmental pollution caused by discarding a metal/ plastic composite. SOLUTION: A metal/plastic composite is immersed in a powder fluidized bed at 200-800 deg.C containing a plastic decomposition catalyst to decompose or melt the plastic component in the composite to transfer it into the fluidized bed, and the fluidized bed is then separated. It is desirable that the powder fluidized bed comprises a plastic decomposition catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating waste plastic, and more particularly to a method for quickly and easily treating a metal composite waste plastic in which a metal such as a scrap car and various kinds of plastics are intricately intermingled. The present invention relates to a method for recovering a metal contained in a fuel as a metal source and a plastic as fuel or the like.

[0002]

2. Description of the Related Art In recent years, synthetic resins such as plastics have been increasing as industrial wastes and general wastes, and their disposal has become a serious social and environmental problem. Above all,
Plastic, which is a component of the incinerator, generates a large amount of heat when it is burned, and requires special incineration equipment due to problems such as damage to the walls of the incinerator when incinerated. Harmful metals such as lead also have problems such as the need for their recovery and immobilization technology. Under such circumstances, dumping is currently performed. However, dumping causes deterioration of the landfill and is not preferable in terms of environmental measures. In recent years, with the increase in disposal costs, securing land for landfills has become a social problem. For this reason, the development of a large-scale treatment method of metal-composite waste plastic without dumping has been desired.

As a method for treating this waste plastic, 2
There is known a method of heating and melting a low-boiling metal or alloy having a melting point of 00 ° C. to 400 ° C., and immersing and decomposing waste plastic for a certain period of time (Japanese Patent Laid-Open No. 50-9 / 1988)
677). This method has been developed as a method for dehydrochlorinating a polyvinyl chloride resin prior to incineration because harmful hydrogen chloride is generated when the resin is treated in an incinerator.

Further, a method is known in which an edible oil waste liquid is used as a solvent to remove an adhesive resin such as polyethylene from a metal material to extract the metal (Japanese Patent Laid-Open No. 5-147041).
No.). As a similar method, using a molten salt at a temperature of 250 to 300 ° C. at which the plastic material is fluidized, controlling the molten salt to the above temperature by heating, and further heating the molten salt to 2 ° C. to 5 ° C. higher than the above temperature The plastic waste is separated by pouring the plastic waste into it, and the plastic material that has been fluidized floats on the liquid surface of the molten salt, and metal and glass materials settle below the liquid surface, and There is also known a method of separating and recovering a plastic waste from a metal material or a glass material by using a molten salt (Japanese Patent Laid-Open No. 8-108165).

[0005] Technology development relating to shredder dust treatment is also being studied diligently, and volume reduction, incineration using an incineration melting furnace including power generation, gasification treatment, and the like are being developed.

[0006]

In the above prior art, plastic is separated from a composite of a specific resin and a metal by a specific medium, and the plastic is reused. On the other hand, many kinds of composite materials such as glass-reinforced composite materials are used in automobiles, home electric appliances, OA equipment, and the like, in addition to various types of plastics. The metals used are of various types such as aluminum, copper, zinc, and lead, in addition to various steel materials such as steel plates and steel bars. Performing a material cycle from such a metal-resin composite waste has many problems in these prior arts.

For example, when a molten metal is used as a molten liquid as disclosed in Japanese Patent Application Laid-Open No. 50-9677, components harmful in the refining process of the metal accompany the metal, which is not preferable. Further, when a molten salt is used, an alkali which is a component of the molten salt is entrained in the metal to be recovered, causing deterioration of the furnace wall of the melting furnace.

Furthermore, efficient separation and regeneration of a molten liquid is indispensable for economically recovering metals and plastics, but this prior art does not consider this measure. In particular, when a molten metal is used, the regeneration of the molten metal is extremely inefficient because the molten metal is converted into chloride by a reaction with hydrogen chloride generated by decomposition of polyvinyl chloride.

In the case of a molten salt, the plastic used as a composite material in the process of processing has a high density, so that the plastic remains in the molten salt and may not be able to float and separate. However, its use requires a pulverizing step, and when used as fuel, it cannot be applied to waste containing various types of resins and composite materials. Further, physical properties such as viscosity of the molten salt may change due to metals eluted from the metal composite waste plastic, and it is extremely difficult to remove and regenerate them. Furthermore, since polypropylene and polyethylene have excellent thermal stability, a treatment temperature of 400 ° C. or higher is required. In the case of a molten nitrate, NOx is generated, which poses a problem in operation.

It is an object of the present invention to provide a method for recovering metal and resin components, which enables metal and plastic components to be efficiently separated from metal-composite waste plastics composed of various types of materials and enables material recycling.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended to convert a metal composite plastic to 200 to 800 ° C. containing a plastic decomposition catalyst.
A metal component from the metal composite plastic, characterized by decomposing or melting the plastic component in the metal composite plastic by transferring it into the fluidized bed, and then separating the fluidized bed. This object has been achieved by a method for recovering a resin component.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The type of waste metal composite plastic to which the present invention can be applied is not limited. For example, waste automobiles, waste home appliances, waste OA equipment and the like can be applied. These metal-composite waste plastics can be processed as they are, but may be shredded with a shredder or the like. The size of the strip is about 1 to 100 mm, especially 2 to 20 mm
mm is preferable.

As the plastic decomposition catalyst, acid catalysts such as Lewis acid and Bronsted acid can be used, and silica-alumina-based or zeolite-based FCC catalysts and hydrogenolysis catalysts which are industrially used are used. Solid acids and the like can be used. Although it is desirable that the cracking catalyst be recovered after treatment and reused, it is also preferable to use an industrially used catalyst in one way. A regeneration tower for performing an oxidation treatment can be used for the regeneration. This plastic decomposition catalyst is a solid powder even at the operating temperature, and has an average particle size of 0.01.
A thickness of about 10 to 10 mm, preferably 0.02 to 5 mm is suitable.

The particles forming the fluidized bed may be only a plastic cracking catalyst, or may be a mixture with other particles. Other particles are also solid at the operating temperature and improve the fluidity of the fluidized bed and do not decrease the performance of the plastic cracking catalyst. For example, silica sand, alumina powder, beads, and the like can be used. The average particle size of the other particles is about 0.1 to 50 mm, preferably about 0.5 to 30 mm. The amount of other particles used is 99% by weight or less, preferably 95 to 5% by weight of the total particles constituting the fluidized bed.
The degree is appropriate.

As the cracking furnace accommodating the fluidized bed, various known ones can be used. For example, a sand bath can be used.

The fluid medium in the fluidized bed is a gas in principle, and a non-oxidizing gas such as nitrogen or argon is preferable for preventing generation of dioxin.

The processing temperature and the residence time are usually determined so that the decomposition of the plastic proceeds sufficiently. The processing temperature and the residence time vary depending on the kind and the amount of the plastic used.
C., preferably 250 to 700.degree. C., more preferably 350 to 500.degree. C., for about 0.5 to 30 minutes, preferably about 1.5 to 15 minutes. At this time, the decomposition behavior differs depending on the type of plastic, but it generally melts, and the main chain of the plastic is broken by catalytic cracking, depolymerized, and gasified, and the decomposed molecules are converted into gas and cracked oil. It is discharged outside and completely separated from metal. The resulting gas or cracked oil can be used as a metal reducing gas or fuel. Next, the metal removed from the cracking furnace removes the attached catalyst by blowing hot air. When the empty volume is large, it is preferable that the metal is compressed to an appropriate size by a press or the like in order to use a melting furnace for melting the recovered metal efficiently.

As the melting furnace, a furnace used in the field of ironmaking can be used, for example, a shift type melting furnace, cupra or the like can be used. The melting furnace is charged with coke as a heat source, but it is also possible to use the cracked oil and gas separated above. In addition, limestone and the like are appropriately added for the purpose of lowering slag temperature, improving fluidity, and the like. Since the amount of slag generated is smaller than in the blast furnace method, the addition amount may be less than half that of the blast furnace. In addition, the operation may be performed under conditions similar to ironmaking.

[0019]

【Example】

Example 1 A part of an end-of-life vehicle having the configuration shown in Tables 1 to 3 was treated by the method of the present invention as follows.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

The FCC catalyst used for catalytic cracking of heavy oil is bubbled with heated nitrogen, heated to 450 ° C., immersed in a continuously transported conveyer by a conveyor in a sand bath furnace filled with heat, and heat-treated for 2 minutes. Carried out. After heat treatment,
The residue was taken up, transferred to a washing chamber, and blown with hot air in a sealed state to remove the catalyst. The amount of carbon attached to the residue was 2.0% by weight. Further, as a result of collecting and analyzing the product, the cracked oil and the gas yield were 5.15 wt% and 1.12 wt%, respectively, per one end-of-life vehicle.
Next, the obtained residue was compressed to a volume of 1/15 with a press machine (L1000 mm × W1000 mm × H500 m
m). This compact was charged together with coke, limestone, quartzite and serpentine at a charge ratio of 1: 0.2: 0.04: 0.02:
0.01 was continuously charged into a shaft furnace type melting furnace, and oxygen and steam (1.4 / 1) were introduced through the tuyere of the blast furnace.
(Mixing ratio (volume)) was blown, and at the same time, the recovered cracked oil was blown into the residue at a rate of 40 kg / ton to discharge hot metal and slag. The industrial analysis values of the obtained residue after the heat treatment are shown in Table 4, the fuel unit comparison during the operation of the melting furnace is shown in Table 5, and the components of hot metal and slag from the melting furnace are shown in Table 6.

Example 2 A waste vehicle was treated in the same manner as in Example 1 except that ZMS-5 was used as a cracking catalyst and the temperature was 390 ° C. to obtain a residue, gas and cracked oil. As a result of analysis, 2.0% of carbon was attached to the residue, and cracked oil and gas were obtained at a yield of 2.94 wt% and 3.22 wt% from one end-of-life vehicle. After the obtained gas was washed with water, the melting furnace was operated under the same conditions as in Example 1 except that the gas was blown from the tuyere of the melting furnace. The results are shown in Tables 4, 5, and 6.

[0025]

[Table 4]

[0026]

[Table 5]

[0027]

[Table 6]

Comparative Example 1 A waste car was treated in the same manner as in Example 2 except that alumina beads having a diameter of 0.5 mm were used as a fluid medium to obtain a residue, a gas and a cracked oil. As a result of the analysis, about 50% of the plastic contained in the end-of-life vehicle remained in the residue, the yield of cracked oil was 1.8 wt%, and the yield of gas was 0.4 wt%. Since the volatile content of the residue was as high as 8% by weight, soot and tar were expected to be generated, so that the residue could not be used in a melting furnace.

[0029]

According to the present invention, by employing a heat treatment method using a pyrolysis catalyst as a fluid medium, the recovery of metals and resins from waste metal composite plastics becomes easier as compared with the conventional method.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tatsuro Ariyama 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd.

Claims (2)

[Claims] 1. A metal composite plastic is immersed in a fluidized bed of powder at 200 to 800 ° C. containing a plastic decomposition catalyst to decompose or melt the plastic component in the metal composite plastic and transfer it into the fluidized bed. And then separating the fluidized bed to recover metal and resin components from a metal composite plastic. 2. The method for recovering a metal and resin component from a metal composite plastic according to claim 1, wherein the fluidized powder bed comprises a plastic decomposition catalyst.