JP2003183723A - RECYCLING METHOD FOR PLASTIC CONTAINER INCLUDING Al METAL, AND STEELMAKING METHOD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To recycle and utilize plastic containers including Al metal such as a plastic container laminated with Al metal as an inner material, or a plastic container in which Al metal is sandwiched between plastics, at a low treatment cost. <P>SOLUTION: This method comprises cutting the plastic container including Al metal into two or more pieces, and using the cut plastic container, as one or more materials out of a deoxidizer, an alloy content additive, and a heating agent, in smelting or refining metals. The cut plastic container is preferably used in as unseparated state without being separated to the Al metal and the plastic. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recycling a plastic container containing metal Al and a steelmaking method using this plastic container.

[0002]

2. Description of the Related Art In recent years, a plastic container containing a plate-shaped or foil-shaped metal Al is lighter and cheaper than a metal cylinder, so that a medical oxygen cylinder or an automobile natural gas container is used. It has come to be used for gas cylinders.

If this used plastic container can be separated into a metal Al part and a plastic part,
Each of them can be recycled. For example, when the plastic part is carbon FRP, it is extremely difficult to process such as cutting due to the coating part of carbon FRP, and when it is finely cut, Conventionally, this plastic container has been compelled to be landfilled as waste due to the fact that dust must be removed because dust is generated and the cost of recycling is high due to these factors.

[0004]

Since Al is an expensive metal and an extremely large amount of Al is used in various fields in modern society, a plastic container containing metal Al contains metal Al inside. From the viewpoint of resource saving, it must be said that the landfill disposal of the plastic left undisturbed is extremely problematic, and the landfill disposal of plastic that is extremely difficult to decompose in the natural world is not preferable in terms of environmental measures. Therefore, the development of an effective recycling utilization method has been earnestly desired, but the technical establishment at an appropriate processing cost has been delayed, and a major problem is that there is no suitable recycling processing method.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for recycling and utilizing a plastic container containing metal Al at a low processing cost.

[0006]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above problems. The examination results will be described below.

Conventionally, since the metal Al portion and the plastic portion of the plastic container containing the metal Al have been individually recycled, the plastic container is crushed or cut and separated into the metal Al portion and the plastic portion. However, if the method is to use the metal Al part and the plastic part at the same time, it is not necessary to separate them. .
The "plastic container containing metallic Al" in the present invention means a plastic container in which metallic Al is internally provided as a liner material inside the plastic, or a plastic in which metallic Al is sandwiched between plastics. It is a container, etc.
Is a plastic container whose constituent is.

Plastic mainly contains carbon and hydrogen, and the heat generated when burning these can be utilized as a heat source for smelting or refining metals. Further, the plastic can also be utilized as an additive for the carbon component of the molten metal. On the other hand, it is well known that Al has an extremely strong affinity with oxygen and is used as a reducing agent and a deoxidizing agent in the smelting and refining of metals.
It is also used as an alloying component additive in steel products. Further, it is also known to utilize the heat generated by the combustion of Al as a heat raising agent for molten metal.

Therefore, if a plastic container containing metal Al is used as a deoxidizing agent, an alloying component additive, or a heating agent in the smelting or refining of metal, the plastic container becomes a metal Al part and a plastic part. It was found that there is no need to separate them and that both can be used effectively at the same time. However, if the shape of the container is left as it is, the effective utilization of the metal Al part is hindered, and there is a risk of explosion due to volatile components such as water and gas remaining in the container when the molten metal is charged,
Therefore, in order to prevent these, it was also found that it is necessary to cut the plastic container into at least two or more parts and directly expose the metal Al part to the smelting atmosphere or the refining atmosphere.

The present invention has been made on the basis of the above findings, and a method for recycling a plastic container containing metal Al according to the first invention is such that a plastic container containing metal Al is cut into two or more pieces and the cut plastic is cut. It is characterized in that the container is used as one or more of a deoxidizing agent, an alloy component additive, and a heating agent in smelting or refining of metal.

According to a second aspect of the present invention, there is provided a method for recycling a plastic container containing metal Al, which is the same as the first aspect, except that the cut plastic container is not separated into metal Al and plastic, but a deoxidizer and an alloy component additive. It is characterized in that it is used as one kind or two or more kinds of the heat raising agents.

In the steelmaking method according to the third aspect of the present invention, when refining molten pig iron or molten steel, a plastic container containing metal Al, which is cut into two or more parts, is added with a deoxidizing agent, an alloy component additive, and a rising agent. It is characterized in that it is used as one kind or two or more kinds of heat agents.

A steelmaking method according to a fourth invention is characterized in that, in the third invention, the plastic container is used as a deoxidizing agent used in the desulfurization treatment of the hot metal.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. INDUSTRIAL APPLICABILITY The present invention cuts a plate-shaped or foil-shaped plastic container containing metal Al and recycles it as a deoxidizing agent, an alloying component additive, or a heating agent in the smelting or refining of metals. In this case, the shape or material of the plastic container does not matter, and for example, FRP containing carbon fiber does not pose any problem. Further, although the plastic containers to be recycled are mainly used ones, it goes without saying that plastic containers that are discarded without being used for some reason are also to be recycled.

In recycling, first, a plate-shaped or foil-shaped plastic container containing metal Al is cut into two or more parts. FIG. 1 is a diagram showing an example in which a plastic container 5 containing metal Al is cut by a cutter 6 having a rotary blade and divided into two parts. In this case, the cutting means is not limited to the cutter 6 shown in FIG. 1, which is capable of cutting refractory material, ceramics, etc., and can cut the plastic container 5 containing metal Al. ,
Any cutting means may be used. However, cutting to a small size requires a large amount of cutting time or generates a large amount of dust, which leads to an increase in the recycling processing cost. Therefore, the number of cuttings is preferably once.

The cut plastic container is used as it is in a metal smelting process or a refining process without being separated into a metal Al part and a plastic part. Recycling without separation can reduce the recycling cost. In the metal smelting process and refining process,
It is normal to perform multiple functions such as deoxidation, addition of alloying components, and heat raising at the same time, and quality control of added raw materials, for example, if volatile components and moisture can be controlled,
Even if the added raw material is composed of a plurality of constituents, there is no problem at all, and therefore, a cut product of a plastic container in which a metal Al part and a plastic part are mixed can be used without any problem.

Due to the characteristics of the metal, Al can have a function as a deoxidizer, a function as an alloy component additive, and a heat-up function by reacting with oxygen. or,
Although plastics are mainly composed of carbon and hydrogen and are solid at room temperature, they often have a melting point in the range of 200 to 500 ° C. and have a heating function by a gasification reaction in a high temperature atmosphere or high temperature molten metal. In addition to being capable of recovering the fuel gas as a fuel gas, it is also possible to provide a heat-up function due to the heat generation effect of combustion in the coexistence of oxygen. Therefore, it is effective to use it in a smelting process or a refining process that requires such a function.
Further, by cutting into two or more parts, it is possible to control the presence or absence of volatile components, water, etc. in the plastic container, and to maintain a certain quality.

In particular, the metal Al obtained in this way
By using a cut product of a plastic container, in which the metal part and the plastic part are mixed, in the steelmaking refining process in the steelmaking process, the deoxidizing function by Al, the function as an alloying component additive of Al, and the heating function by plastic Can be effectively exerted. As for the method of adding the cut product, it is appropriate to add it from above the refining vessel, and this method can be used without problems. Hereinafter, in the present embodiment, an example of preliminary deoxidation of hot metal contained in a blast furnace ladle will be described as an example of recycling utilization in a steelmaking and refining process of an ironmaking process.

The preliminary deoxidation of the hot metal in the blast furnace pan is carried out before the desulfurization treatment in the hot metal desulfurization step which is reduction refining. FIG. 2 shows a schematic diagram of the equipment configuration in the hot metal desulfurization process. As shown in FIG. 2, a cut piece 7 of a plastic container containing metal Al and containing a hot metal 3 and a hopper 9 installed above the blast furnace ladle 1 with respect to the blast furnace ladle 1 mounted on a trolley 2. It is supplied to the hot metal 3 through the charging chute 10. Blast furnace pot 1
The slag 4 added for the purpose of heat retention floats inside. In this equipment, in order to make the deoxidation and desulfurization of the hot metal 3 proceed more effectively, the rotary blades 8 which rotate about the shaft core are installed. Although FIG. 2 shows a mechanical stirring type desulfurization equipment, a desulfurization equipment provided with an injection lance for blowing a stirring gas may be used instead of the rotary blade 8.

In such equipment, the molten metal 3 is agitated by the rotor 8 while the cut material 7 of the plastic container containing metal Al is charged into the bath surface of the hot metal 1, and the hot metal by the metal Al portion in the cut material 7 is agitated. The deoxidation of 3 is effectively advanced.
A part of the plastic part in the cut product 7 is burned by oxygen in the atmosphere or oxygen in the hot metal 3 to heat the hot metal 3, and a part of the plastic part directly reacts with the hot metal 3 to generate hot metal. Increase carbon concentration (carburize). When a predetermined amount of the cut material 7 is charged and the preliminary deoxidation of the hot metal 3 is completed, a desulfurizing agent (not shown) is subsequently added to start the desulfurization treatment of the hot metal 3.

In addition, as another application method to the steel refining process, the current metal Al is used as a deoxidizer after converter decarburization blowing.
It can also be applied to the use as a substitute for, the use as a deoxidizing agent in the secondary refining process, and the like. Further, for the purpose of simplifying the cutting process of the plastic container and enabling a large amount of the cut products 7 to be charged, the cut products 7 of the plastic container containing the metal Al are packed in FIBC, and each FIBC is charged to the bath surface. You may add by the method. According to this method, a large amount of the cut product 7 can be quickly added,
The refining time can be shortened.

[0022]

EXAMPLES Examples of the hot metal desulfurization process having the equipment structure shown in FIG. 2 will be described in detail below. A plastic container (outer diameter: 150 mm, length: 400 mm, mass: 2 kg) containing metal Al, which is composed of an aluminum liner (mass 60%) and FRP (mass 40%), and has a rotary blade as shown in FIG. It was cut into two parts with a size that can be handled by a cutter. The metal A thus obtained
After confirming that volatile components and water do not exist in the cut product in which 1 and plastic are mixed, it is packed in a flexible container,
A flexible container containing 20 kg was prepared. In addition, in the present example, the addition was performed using the hopper and the charging chute, and was added in the state of being packed in the flexible container.

The hot metal used is hot metal that has been desiliconized in the blast furnace casting after being tapped from the blast furnace, and the hot metal composition is Si≤
0.10 mass%, C = 4.3 to 4.6 mass%, S = 0.
031 to 0.034 mass%, hot metal temperature 1330 to 1
It was 430 ° C. 200 tons of hot metal is contained in the blast furnace pot, and the desiliconization slag generated in the previous desiliconization process is removed from the blast furnace pot.

While stirring the hot metal with a rotary blade, a cut product made of a mixture of metal Al and plastic and packed in a flexible container was put on the hot metal. In the hot metal desulfurization process,
In order to accelerate the desulfurization reaction, it is usual to perform pre-deoxidation of hot metal with Al as a pretreatment of desulfurization treatment, and aluminum ash (Al
The cut product was used as a substitute for pure content: 40 mass%. Then, following this preliminary deoxidation, a desulfurizing agent was added to the hot metal with a rotary blade while stirring to perform desulfurization treatment.

As the desulfurizing agent, quick lime mixed with 5 mass% of fluorite is used, and the basic unit of the desulfurizing agent is quick lime +
The pure amount of fluorite was set to a constant value (6 kg / t), and the operating parameters at the time of desulfurization, the rotational speed of the rotor, the desulfurizing agent supply rate, and the hot metal stirring time were set to constant values. Further, the S concentration in the hot metal before and after the desulfurization treatment was measured, and evaluated by the desulfurization rate and the hot metal S concentration after the treatment (passed at 0.003 mass% or less). Table 1 shows the operating conditions and the operating results in the example of the present invention and the conventional example performed as a comparison.
In addition, the ○ mark in the judgment column of Table 1 represents “pass”,
Example 1 and Example 2 are operations in which the input Al basic unit is the same as that of the conventional example and the mixing ratio of the cut product of the plastic container to aluminum ash is changed, and Example 3 is the operation without using aluminum ash. It is an operation that uses only cut pieces of plastic containers.

[0026]

[Table 1]

As shown in Table 1, although the amount of the desulfurizing agent added was the same and the stirring conditions of the hot metal were the same,
It has been found that when a plastic container containing metallic Al is charged as an alternative to the Al source, a desulfurization effect equal to or higher than that of the conventional method can be obtained with the same or less amount of Al unit consumption as in the conventional method. That is, the usefulness of the method of the present invention was confirmed.

[0028]

Industrial Applicability According to the present invention, it becomes possible to easily and inexpensively recycle the plastic containing metal Al, which is used for medical oxygen cylinders, natural gas cylinders for automobiles, etc., and particularly steel refining process. When recycled in, it is possible to perform deoxidation at low cost and effectively,
A reduction in the manufacturing costs of steel products is achieved, with beneficial industrial effects.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing cutting of a plastic container made of an aluminum liner and FRP.

FIG. 2 is a schematic diagram of an equipment configuration in a hot metal desulfurization step.

[Explanation of symbols]

1 blast furnace pot Two dolly 3 hot metal 4 slag 5 plastic containers 6 cutter 7 cuttings 8 rotors 9 hopper 10 throwing chute

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihiko Inoue             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Tomoo Izawa             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Tadaaki Hino             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Toshiro Ishige             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Yoshiaki Tabata             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. F term (reference) 4K013 BA05 BA08 BA16 CD07 EA19                       EA29

Claims (4)

[Claims] 1. A plastic container containing metal Al is cut into two or more parts, and the cut plastic container is one or two of a deoxidizing agent, an alloying component additive, and a heating agent in smelting or refining of metal. A method for recycling a plastic container containing metal Al, which is used as a seed or more. 2. A deoxidizing agent, an alloy component additive, without separating a cut plastic container into metallic Al and plastic.
The method for recycling a plastic container containing metal Al according to claim 1, wherein the method is used as one or two or more of the heat raising agents. 3. When refining molten pig iron or molten steel, a plastic container containing metal Al, which is cut into two or more parts, is used as one of a deoxidizing agent, an alloying component additive, and a heat raising agent. Alternatively, the steelmaking method is characterized by using two or more kinds. 4. The steel making method according to claim 3, wherein the plastic container is used as a deoxidizing agent used in desulfurizing hot metal.