JP4465798B2 - How to collect and recycle used aluminum cans - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to recovery and recycling method of used aluminum cans for recycling aluminum cans such as beverage cans are recovered after use and the like.
[0002]
[Prior art]
A large amount of aluminum cans that are lightweight and excellent in workability and corrosion resistance are used as containers for various carbonated drinks and alcoholic drinks.
In such an aluminum can as a beverage container, the electrical energy required for redissolving and recovering and using it is only a few percent of the electrical energy required for new production by electrolytic refining. For this reason, in recent years, due to the growing demand for energy conservation and global environmental protection and effective use of resources, the used aluminum cans are collected and reused as various aluminum products.
[0003]
FIG. 2 shows a conventional method for recovering and recycling used aluminum cans of this type. A recovery product mainly made of used aluminum pressed into a block of a certain size by a recovery company is used as a truck or the like. First sent to the collection / sorting factory by means of transport, where it is crushed by a crusher to separate and remove non-aluminum metal such as iron cans and plastics contained in the interior, and then sorted used aluminum Cut the can into smaller pieces.
[0004]
Next, the obtained aluminum can cut piece is carried into a reclaimed lump manufacturing factory by a transporting means such as a truck, where it is first roasted to remove organic matter such as paint and resin layer adhering to the surface. It is made to burn, and the remainder is removed as carbides and oxides and then dissolved, and this is cast into a reclaimed mass.
Then, the obtained reclaimed mass is again transported to the melting / rolling factory by transport means, melted again, and after adjusting the alloy to obtain the aluminum alloy necessary for reuse, it is cast to produce a slab And this is rolled and shape | molded to a raw material aluminum plate.
[0005]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional method for recovering and recycling used aluminum cans, it is necessary to transport between a plurality of factories having equipment necessary for each process by means of transportation such as trucks, and manufacture of recycled ingots. In factories and melting / rolling factories, a total of two melting steps and casting steps are required, so there is a problem that overall energy is wasted and inferior in economic efficiency. Reduction of the unit price of the alloy has been desired.
[0006]
Also, especially in the collection / sorting factory, the collected material that has been press-molded by the collection company contains substances that emit off-flavors, such as spoiled remaining beverages, and strawberries, cockroaches and their eggs. There was also a problem of adversely affecting the surrounding environment and work environment during storage before the crushing process and during the crushing work.
[0007]
The present invention has been made to effectively solve the problems of the above-described conventional methods for recovering and recycling used aluminum cans, and efficiently separates and recovers aluminum alloys mainly from recovered materials including used aluminum cans. It is an object of the present invention to provide a method for recovering and recycling used aluminum cans that can be reused and therefore can reduce the unit price of recycled aluminum alloy and is excellent in terms of economy and environment .
[0008]
[Means for Solving the Problems]
The method for recovering and recycling a used aluminum can according to the present invention as set forth in claim 1 includes a fumigation step of fumigating a bulk recovered material mainly composed of a used aluminum can, and a pulverization for pulverizing the recovered material. A step of separating the non-aluminum material from the obtained recovered product, and baking the selected aluminum can and maintaining the roasted aluminum can in a temperature range of 200 ° C. to 550 ° C. The slab or reclaimed lump from the roasting step of removing the deposits by supplying to the vibrating sieve as it is, the melting step of melting the aluminum can through the roasting step, and the molten aluminum obtained in the melting step The obtained casting process is performed continuously and continuously.
[0009]
At this time, the invention described in claim 2 performs an adjustment step of adjusting the alloy while maintaining the aluminum obtained in the melting step of claim 1 in a molten state, and then from the molten metal adjusted in the alloy A casting process is performed.
[0010]
The invention of claim 3 is the invention according to claim 1 or 2, the fumigation process is characterized in that performed by injecting steam into the harvest.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a used aluminum can recovery and recycling facility according to the present invention. This recovery and recycling facility is mainly composed of a lump of used aluminum cans carried by a transport means such as a truck. The non-aluminum material is separated from the fumigation device 1 for fumigating the collected material with water vapor, the breaker 2 for crushing the collected material, and the collected material crushed by the breaker 2. In the melting furnace 5, the sorting means 3, the rotary kiln (roasting furnace) 4 for roasting the aluminum can passed through the sorting means 3, the melting furnace 5 for melting the aluminum can discharged from the rotary kiln 4, A slab is obtained from a holding furnace 6 for adjusting the alloy while holding the obtained aluminum in a molten state, and a molten metal whose alloy is adjusted in the holding furnace 6. Has been schematically composed caster 7 for, devices such containing them, are disposed sequentially consecutively in one site 8.
[0014]
Here, in the vicinity of the fumigation device 1, a place 9 for temporarily placing the fumigated collected material is provided, and the collected material is sequentially transferred from the place 9 to the breaker 2 by a conveying means such as a forklift. It is supposed to be sent. In addition, the sorting means 3 includes a magnetic separator 3a that adsorbs and removes irons by magnetism, and air is sprayed on the collected material, thereby reducing plastics and scraps that are lighter than an aluminum can and the aluminum can. The wind power sorter 3b separates and removes heavy metals such as copper and stainless steel. Here, between the breaker 2, the magnetic separator 3a, and the wind separator 3b, the belt conveyors 10a and 10b are arrange | positioned as a conveyance means, respectively. A primary stock hopper 11 is provided on the downstream side of the wind power sorter 3b via a conveyor 10c, and the discharge side of the hopper 11 is guided to the rotary kiln 4 via a conveyor 10d.
[0015]
Further, on the downstream side of the rotary kiln 4, a vibrating sieve 12 is continuously disposed via a belt conveyor 10e, and an aluminum can passed through the vibrating sieve 12 is introduced into the melting furnace 5 by the belt conveyor 10f. It has become. In addition, a storage furnace 14 is provided on the discharge side of the melting furnace 5 via a trough 13, and the discharge side of the storage furnace 14 is connected to the charging side of the holding furnace 6 by a trough 15a.
[0016]
And between this holding furnace 6 and the casting machine 7, the degassing apparatus 16 for removing hydrogen gas, troughs 15b, 15c, and 15d in sequence, and nonmetal present as floating slag and solid particles A molten metal filtration device 17 for removing inclusions is provided, and the cast slab obtained by the casting machine 7 is transported to the weighing machine 18 by the overhead crane and the forklift, and then sent to the storage 19 by the forklift. It has become.
[0017]
Next, an embodiment of a method for recovering and recycling a used aluminum can according to the present invention will be described using the recovery and recycling facility having the above configuration.
In the above recovery / recycling equipment, a large collection of mainly used aluminum cans, which are mostly pressed into blocks of a certain size by a recovery company, is carried in by a transport means such as a truck. Waste cans such as surplus materials generated during cutting and pressing in the manufacturing process of aluminum cans are carried in, as are recovered aluminum cans that are not partially pressed.
[0018]
And after carrying in, the fumigation apparatus 1 fumigates at least the lump-like collect | recovered material with water vapor | steam in the fumigation apparatus 1 first. This kills the microorganisms that cause the off-flavor contained in the recovered material, and kills the spiders, cockroaches, etc. contained in the inside and their eggs. The recovered material that has been subjected to the fumigation process is temporarily placed in the temporary storage 9 in accordance with the process of regeneration process described later.
[0019]
Next, the bulk collection temporarily placed in the storage place 9 is sequentially sent to the breaker 2 and crushed (pulverization step), and then sent to the magnetic separator 3a by the belt conveyor 10a. In the magnetic separator 3a, an iron can or the like is sent. After removing the non-aluminum material having magnetism, it is further sent to the wind power sorter 3b by the belt conveyor 10b and jetted with compressed air, so that plastics and paper scraps that are lighter than aluminum cans, and aluminum cans Separates and removes non-magnetic metals such as copper and stainless steel and concrete fragments that are heavier (sorting process).
[0020]
In this way, organic substances such as paint and resin layer adhere to the surface of the separated used aluminum can, and if it is dissolved as it is, gas is generated vigorously in the molten metal due to combustion of the paint and resin layer. Oxidation loss of aluminum is increased, or Ti is mixed into the molten metal from TiO ₂ in the coating, and primary intermetallic compounds are crystallized by aluminum and peritectic reaction. Become.
[0021]
Therefore, the separated used aluminum cans are temporarily stored in the stock hopper 11 by the conveyor 10c, and are put into the rotary kiln 4 every predetermined amount via the conveyor 10d. And in this rotary kiln 4, the said organic substance adhering to the surface is directly vaporized and burned by carrying out the roasting process at a temperature lower than the melting point of aluminum (roasting process), and the remainder is made into carbides and oxides. Later, the further roasted aluminum can was kept in the temperature range of 200 ° C. to 550 ° C. and supplied to the vibrating sieve 12 via the belt conveyor 10e, and was not removed in the carbide and oxide and the sorting step. Separate deposits such as sand (separation process).
[0022]
Next, the used aluminum cans that have passed through the vibrating sieve 12 are sequentially put into the melting furnace 5 via the belt conveyor 10e and melted. In addition, waste materials such as surplus materials generated in the cutting process or press process in the manufacturing process of the aluminum can are directly put into the melting furnace 5 or the holding furnace 14 and melted (melting process).
[0023]
Then, the molten aluminum alloy is transferred to the temporary holding furnace 14 through the trough 13, and the molten metal in the holding furnace 14 is sent from the trough 15a to the holding furnace 6. Incidentally, in the recovered aluminum can, although 80% or more of the can weight is occupied by the body material formed by the A3004 material which is usually an Al-Mn alloy, the end material constituting the aluminum can is Al. -A5052A, 5082 material or A5182 material etc. which are Mg-type alloys are used, and A5182 material etc. are used as a tab. Therefore, when a used aluminum can is regenerated and used as a body material in a new aluminum can, it is necessary to adjust the alloy components. Therefore, in the holding furnace 6, the alloy is adjusted so that the aluminum alloy required for reuse is obtained.
[0024]
Further, the molten metal whose alloy is adjusted in the holding furnace 6 contains hydrogen which is a gas that is easily dissolved in aluminum. This hydrogen does not form a compound with aluminum, but the amount dissolved in the molten metal is several tens of times larger than that in the case of a solid, so that it becomes supersaturated during casting and generates pores in the slab or sinks. Causes nest defects. The molten metal also contains non-metallic inclusions such as oxides that exist as solid particles at a temperature equal to or higher than the liquid phase of the aluminum alloy. If cast as it is, deterioration of mechanical properties and generation of surface defects will occur. Invite.
[0025]
Therefore, the molten metal that has passed through the holding furnace 6 is sent from the trough 15b to the in-line degassing device 16, and the hydrogen contained in the molten metal is degassed together with various non-dissolving gases that are separately supplied, and further from the trough 15c. After the non-metallic inclusions and the like are removed by sending to the filtration device 17, the trough 15d is sent to the casting machine 7 and cast into a slab. Then, the obtained slab is transported to the weighing machine 18 by a crane and a forklift and weighed, then transferred to the slab storage 19 by a forklift and stored, and appropriately transported to an aluminum strip rolling mill.
On the other hand, aluminum dross produced as an oxide during melting and holding is scraped from the melting furnace 5, the holding furnace 14, and the holding furnace 6, and several tens percent of the aluminum component is recovered by a rotary vane-type drawing machine. After being done, the remainder is sent to the hopper.
[0026]
Thus, according to the used aluminum can recovery and recovery equipment and recovery and recycling method having the above-described configuration, the recovered material crushing step, sorting step, roasting step, melting step, alloy adjustment step, and casting step are all performed. Since it is performed consistently and continuously in the site 8, there is no need to transport between multiple factories having equipment necessary for each process by means of transportation such as trucks as in the past, and multiple times Therefore, it is possible to greatly reduce the unit production cost of the recycled aluminum alloy.
[0027]
In addition, since the recovered material sent to the recovery / regeneration facility is first fumigated with steam in the fumigation device 1, microorganisms that cause off-flavors are killed, and spiders, cockroaches and their eggs are removed. Can be killed. As a result, even if it is stored in the storage place 9 for a certain period of time before the crushing process is performed in the subsequent breaker 2, the surrounding environment and the working environment are not adversely affected.
[0028]
At this time, as the fumigation step, it is economical because it uses water vapor that is easy to handle and has a low unit cost. In particular, an aluminum alloy has an excellent thermal conductivity and corrosion resistance, and therefore has a temperature of about 100 ° C. Even when steam, which is a moist heat source, is used, the effect of sufficient sterilization and the like can be obtained up to the inside of the massive collection. In addition, since the recovery / regeneration facility has facilities for generating high-temperature exhaust gas such as the rotary kiln 4 and the melting furnace 5, it is much cheaper by generating the water vapor using the exhaust gas. Water vapor can be obtained.
[0029]
Furthermore, since the used aluminum can roasted in the rotary kiln 4 is supplied to the vibrating sieve 12 while being kept in a high temperature range of 200 ° C. to 550 ° C., it is put into the melting furnace 5 as it is and melted. Moreover, the amount of heat of melting required in the melting furnace 5 can be reduced, and further energy saving can be achieved.
[0030]
Moreover, once the aluminum can is cooled and supplied to the vibrating sieve 12 after the roasting step, condensation occurs on the surface of the aluminum alloy having excellent thermal conductivity, and the powdery TiO ₂ adheres, thereby separating and removing. However, since the used aluminum can with the high temperature described above is supplied to the vibrating sieve 12, the TiO ₂ or the like can be removed smoothly without adhering to the surface. Rust or the like adheres to the vibrating sieve 12 due to condensation, and transfer adheres to the used aluminum can to which it is supplied, so that there is no risk of quality degradation when it is melted later.
[0031]
In the above-described embodiment, the case where the recovered used aluminum can is regenerated and reused as the body material of the aluminum can has been described. However, the present invention is not limited to this. It is possible to recycle as a raw material necessary for products made of various aluminum alloys by adjusting the alloy in and adding aluminum separately. Therefore, the casting machine 7 is not limited to the case of casting into a slab as shown in the present embodiment. For example, when the casting machine 7 is regenerated as an extruded material, a billet casting machine may be applied. Is possible.
[0032]
Further, in the above embodiment, the case where the fumigation process is performed by injecting water vapor onto the recovered material has been described. However, the present invention is not limited to this. If the main purpose is to prevent adverse effects, a fumigation process by spraying an insecticide may be provided instead of the above steam, and according to this, the equipment cost is further reduced than when steam is used. Can be achieved.
[0033]
【The invention's effect】
As explained above, according to the invention according to any one of claims 1 to 3 , from the crushing step of the recovered material mainly composed of used aluminum cans, the selection step, the roasting step, the melting step, the alloy adjusting step, and Since the casting process is performed consistently and continuously within one site, there is no need to transport between multiple factories with equipment necessary for each process by means of transportation such as trucks. Moreover, since multiple melting and casting are not required, the overall economy is excellent, and the manufacturing unit price of the recycled aluminum alloy can be greatly reduced.
[0034]
In addition, since the collected mass is first fumigated, it can kill microorganisms that cause bad odors, as well as spiders, cockroaches and their eggs, which can adversely affect the surrounding environment and work environment. In addition to the effect that there is no effect, the amount of heat of melting required in the subsequent melting furnace can be reduced, and further energy saving can be achieved . In particular, according to the invention described in claim 3, which is excellent in economical efficiency, it is possible to obtain a sufficient sterilization effect to the inside.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of a used aluminum can recovery and recycling facility according to the present invention.
FIG. 2 is a schematic configuration diagram for explaining a conventional method for collecting and recycling aluminum cans.
[Explanation of symbols]
1 Fumigation device 2 Breaker
3 Sorting means 3a Magnetic separator 3b Wind separator 4 Rotary kiln (roasting furnace)
5 Melting furnace 6 Holding furnace 7 Casting machine 8 Site 10a-10f Belt conveyor 13, 15a-15d Trough

Claims (3)

A fumigation step for fumigating a bulk recovered material mainly composed of used aluminum cans, a crushing step for crushing the recovered material, and a sorting step for separating the non-aluminum material from the recovered material obtained, A roasting process in which the selected aluminum can is roasted and the roasted aluminum can is supplied to a vibrating sieve while being kept in a temperature range of 200 ° C. to 550 ° C. to remove deposits, A used process characterized by consistently and continuously performing a melting process for melting the aluminum can through the baking process and a casting process for obtaining a slab or a reclaimed mass from the molten aluminum melted in the melting process. A method for collecting and recycling aluminum cans.   2. The used aluminum according to claim 1, wherein an adjustment step of adjusting the alloy is performed while maintaining the aluminum obtained in the melting step in a molten state, and then the casting step is performed from the molten metal adjusted in the alloy. How to collect and recycle cans.   The method for recovering and recycling a used aluminum can according to claim 1 or 2, wherein the fumigation step is performed by spraying water vapor onto the recovered material.

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