JPH08112580A - Continuous treatment of combined waste - Google Patents

Abstract

PURPOSE: To recover a residue increased in metal content and rich in metal and an oil improved in quality from the combined waste consisting of metal and plastics. CONSTITUTION: The combined waste is continuously treated in the following first to third stages. The waste is reduced and thermally decomposed at 200-300 deg.C in a first rotary kiln 1 in the first stage to selectively separate halogen from the plastics in the waste. The waste freed from halogen is transferred to a second rotary kiln 2 arranged in series in the second stage. The waste is reduced and thermally decomposed at 550-650 deg.C in the second rotary kiln 2 in the third stage, and the waste is separated into the decomposed gas, decomposed oil and metal-rich residue which are respectively recovered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous treatment method for recovering a metal-rich residue having an improved metal content and an oil having an improved quality from a composite waste of metal and plastic.

[0002]

2. Description of the Related Art Conventionally, most of metal and plastic composite wastes such as shredder dust as household electrical appliances waste and automobile waste have been landfilled. Recently, attention has been paid to resource recovery from complex waste,
There is an increasing number of cases where iron and aluminum with high content in composite waste are recovered by magnetic separators and eddy current separators.
After that, it is landfilled. Further, in recent years, the number of landfills for complex wastes has decreased and the problem of elution of metal components has become apparent, and the number of cases of incineration after recovery of iron and aluminum components has increased.

[0003]

The composite waste after the iron content and the aluminum content are removed contains 5 parts of the plastic part.
It contains 0% or more, and particularly contains a copper content of about 5 to 10%. The copper content can be recovered by the solvent recovery method and the dissolution recovery method in copper refining, but the copper content is low, so that the cost is high and the economic effect is not achieved. Further, regarding the treatment of plastic contained in the composite waste, in the above combustion method, generation of hydrogen halide due to the plastic-containing halogen content, that is, chlorine content and fluorine content, that is, hydrogen chloride and hydrogen fluoride is generated in the boiler. This causes a decrease in heat recovery efficiency.

Further, there is an example in which the composite waste is burned to recover the copper content. However, this causes halogenation of the copper content and other metal content due to the halogen content during combustion, which causes the sublimation of the metal halide produced at low temperature, which may lead to a decrease in the recovery rate and the halogenation that has occurred. Metals adversely affect the copper smelting process.

[0005]

The present invention includes the following first to third aspects.
It is a continuous treatment method of a composite waste consisting mainly of a metal component and a plastic component, which is characterized by comprising steps.

First step: The composite waste is reduced and pyrolyzed in the first rotary kiln at 200 ° C. or higher and 300 ° C. or lower to selectively remove the halogen content from the plastic content in the composite waste.

Second step: The composite waste from which the halogen content has been selectively removed is conveyed to a second rotary kiln which is arranged in series.

Third step: The composite waste is reduced and thermally decomposed in the second rotary kiln at 550 ° C. or higher and 650 ° C. or lower to separate and recover cracked gas, cracked oil and metal-rich residue.

[0009]

Operation: At the first rotary kiln, normal pressure and temperature of 200
In a reducing state of ~ 300 ° C, water with a high possibility of being mixed together with complex waste is removed with the retention time of the object of 10 minutes to 2 hours, and 90% or more of the plastic-containing halogen content is decomposed and released, and discharged as hydrogen halide. To do. As a result, the halogen content is extracted from the composite waste, the halogenation of the recovered metal is suppressed, and the metal recovery rate is improved. Below the temperature range, the decomposition and liberation of halogen components are slow, and the equipment becomes large, and above the temperature range, the thermal decomposition of plastic is promoted, and the yield of cracked gas and cracked oil recovered in the second rotary kiln decreases. On the other hand, the residence time depends on the reduction temperature and the type and shape of the composite waste, but it is preferably 10 minutes to 2 hours in consideration of the free decomposition time of halogen.

In the second rotary kiln, which is directly connected to the first rotary kiln, the residual plastic is thermally decomposed and discharged in a decomposed gas state in a reducing state at atmospheric pressure and a temperature of 550 to 650 ° C. for a residence time of 30 minutes to 2 hours. To do. The metal in the recovered residue, mainly copper, can be recovered without becoming an oxide, and the metal content is also improved, which is a great advantage in the refining process. Also, if there is a large amount of fixed carbon remaining in the residue and it interferes with the refining process, send the residue to an oxidation furnace,
It is also possible to convert fixed carbon into combustion gas. At this time, some of the metals are oxidized, but they do not evaporate or volatilize, and there are few obstacles in the refining process.

If the temperature is lower than the above range, the thermal decomposition of the plastic takes time and the equipment becomes large, and if the temperature is above the above range, the melting and sublimation of the metal component occurs and the possibility of clogging in the kiln increases. Although the residence time depends on the reduction temperature and the type and shape of the composite waste, it is preferably 30 minutes to 2 hours in consideration of the decomposition time of the plastic component.

The cracked gas and cracked oil generated by thermal decomposition can be cooled and stored as cracked gas and cracked oil, and since the halogen content is removed by the first rotary kiln, the energy quality is high and other equipment Can be used as an energy source of the present invention, and can also be used in equipment for carrying out the present invention.

[0013]

EXAMPLE An example of the present invention will be described below with reference to FIG.

As the first and second rotary kilns,
A two-stage series type of external heating type rotary kiln was used.

The first rotary kiln 1 is a raw material hopper 3
In addition, a two-stage gate valve 4 is provided between the raw material hopper 3 and the first rotary kiln 1 to improve the sealing performance. When the raw material is fed into the first rotary kiln 1, the upper gate valve is opened, the raw material is fed between the gate valves, the upper gate valve is closed, the lower gate valve is opened, and the composite waste is fed into the lower pusher portion, and thereafter. Close the lower gate valve. The composite waste is sent to the first rotary kiln 1 by the pusher 5.

The first rotary kiln 1 has an inner cylinder and an outer cylinder, burns fuel inside the outer cylinder and outside the inner cylinder, and reduces and decomposes the composite waste inside the inner cylinder at a temperature of 200 to 300 ° C.
The outer cylinder is fixed and the inner cylinder rotates. In the first rotary kiln 1, the halogen component in the plastic in the composite waste is liberated and decomposed, and the exhaust gas is treated as an acidic gas of hydrogen chloride and hydrogen fluoride.

The exhaust residue of the first rotary kiln 1 contains a large amount of carbon, hydrogen, and oxygen, and these are directly sent to the second rotary kiln 2 which is directly connected. 1st rotary kiln 1 and 2nd rotary kiln 2
The seal 6 between and may or may not have a gate valve. A gate valve is required when using the pusher method for delivery, and a gate valve is not required when using the ruder method because the feed is sealed by the body.

The second rotary kiln 2 has the same external heating system as the first rotary kiln 1 and is of the external fixed type and the internal rotary type. The heating temperature is 550 to 650 ° C., and the cracked gas becomes a high-quality fuel source from which halogen atoms have been removed. Extraction of the decomposition residue is the same as the seal between the first rotary kiln 1 and the second rotary kiln 2.

[0019]

According to the present invention, since the halogen content is selectively discharged from the composite waste mainly consisting of the metal content and the plastic content in the first rotary kiln, the second rotary kiln does not contain halogen content and has a high quality decomposition. It is possible to recover gas, cracked oil, and metal rich residues.

[Brief description of drawings]

FIG. 1 shows an example of a device for implementing the invention.

[Explanation of symbols]

 1 1st rotary kiln 2 2nd rotary kiln 3 Raw material hopper 4 Gate valve 5 Pusher 6 Seal 7 Metal residue extraction

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location C10J 3/00 ZAB A B09B 3/00 302 A (72) Inventor Takaharu Takeuchi 46-59 Nakahara, Tobata-ku, Kitakyushu Nippon Steel Co., Ltd., Machinery & Plant Division (72) Inventor Shigeru Mitarai 46-59 Nakahara, Tobata-ku, Kitakyushu City Inside Nippon Steel Plant Design Co., Ltd.

Claims (1)

[Claims] 1. A continuous treatment method for a composite waste consisting mainly of a metal component and a plastic component, which comprises the following first to third steps. 1st process: Combined waste is 200 in 1st rotary kiln
It undergoes reductive thermal decomposition at temperatures between ℃ and 300 ℃ and selectively removes halogen from the plastic in the composite waste. Second step: The composite waste from which the halogen content is selectively removed is conveyed to the second rotary kiln which is arranged in series. 3rd step: 550 compound waste in 2nd rotary kiln
It undergoes reductive thermal decomposition at temperatures above 650 ° C and is separated and recovered into decomposed gas, decomposed oil and metal-rich residue.