KR20220002779A - Manufacturing method for molded articles and molded articles - Google Patents

Abstract

The present invention relates to a molded body manufacturing method and a molded body. A molded body manufacturing method includes the steps of: a process of laying slag; a process of preparing a plastic for coating and a filling plastic comprising a plastic having a higher melting point than the plastic for coating; attaching the plastic for coating to at least a portion of the slag to manufacture a slag-plastic composite; and a process of manufacturing the molded body by extruding a mixture including the slag-plastic composite and the filling plastic.

Description

Manufacturing method for molded articles and molded articles

The present invention relates to a method for manufacturing a molded article and a molded article, and more particularly, to a molded article manufacturing method and a molded article capable of manufacturing a molded article having excellent mechanical properties by utilizing by-products and waste plastics generated in an ironworks.

The steelmaking process generates a large amount of various types of by-products while manufacturing steel products. One example of these by-products is slag, and the slag is largely classified into blast furnace slag, steelmaking slag, and ferronickel slag. Some of these slags are used as raw materials for cement, fertilizers, paints, and aggregates for civil engineering, but most of them are disposed of in landfills.

On the other hand, plastic has excellent convenience, chemical resistance, etc., and is used as an industrial material not only for various household items, but also for component manufacturers and molding companies. A large amount of plastic is manufactured as a single-use product, and after use, it can be collected and recycled as waste plastic. However, waste plastic is supplied at a very low price and, despite excellent physical properties such as strength and chemical resistance, a large amount is incinerated or disposed of in landfills. In this case, there is a problem in that air, soil and water quality are polluted.

KR 10-1998-044182 A

The present invention provides a molded article manufacturing method and molded article capable of reducing manufacturing cost and reducing environmental pollution.

The present invention provides a molded article manufacturing method and molded article capable of improving the durability and lifespan of equipment.

The present invention provides a molded article manufacturing method and a molded article capable of manufacturing a molded article having excellent mechanical properties.

A method for manufacturing a molded body according to an embodiment of the present invention, the process of providing slag; A process of preparing a plastic for coating and a plastic for filling comprising a plastic having a higher melting point than the plastic for coating; attaching the plastic for coating to at least a portion of the slag to prepare a slag-plastic composite; and extruding a mixture including the slag-plastic composite and the plastic for filling to manufacture a molded body.

The process of preparing the slag may include a component adjustment process of adjusting the CaO content of the slag.

The process of preparing the plastic for filling, the process of collecting two or more different types of waste plastics; Classifying the waste plastic into a high melting point plastic having the highest melting point among the waste plastics and a low melting point plastic having a lower melting point than the high melting point plastic; crushing each of the high-melting-point plastic and the low-melting-point plastic; and preparing the crushed high-melting-point plastic as the filling plastic.

The process of preparing the plastic for filling may include a process of mixing some of the crushed high melting point plastic and the crushed low melting point plastic.

It may include the process of preparing a compatibilizer for mixing the plastic for coating and the plastic for filling.

The process of preparing the compatibilizer may include preparing a compatibilizer including at least one of an epoxy functional group and a maleic anhydride functional group.

The process of preparing the slag-plastic composite may include heating the slag to have a temperature equal to or higher than the melting point of the plastic for coating; The process of injecting the plastic for coating into the heated slag; and attaching a plastic for coating to the surface of the heated slag.

The process of injecting the plastic for coating into the heated slag may include the process of adding 5 to 10% by weight of the plastic for coating with respect to the total of the heated slag and the plastic for coating.

The process of preparing the slag-plastic composite may include maintaining the temperature of the heated slag at a temperature greater than or equal to the melting point of the plastic for coating; agitating the heated slag and the plastic for coating, bringing the plastic for coating into contact with the heated slag, and melting the plastic for coating by using the heat of the heated slag; and attaching the molten coating plastic to the surface of the heated slag.

The process of manufacturing the molded body may include a process of preparing 30 to 80% by weight of the slag-plastic composite with respect to the total of the slag-plastic composite and the plastic for filling.

The process of manufacturing the molded body may include: preparing a compatibilizer in an amount of 1 to 5% by weight with respect to the entire plastic for filling contained in the plastic for filling; and extruding the mixture and the compatibilizer.

The process of manufacturing the molded body may include a process of preparing an additive.

The process of manufacturing the molded body may include extruding the mixture at a temperature equal to or higher than the melting point of the plastic for filling.

The extruding process may include reacting the compatibilizer with at least one of the coating plastic and the filling plastic.

The process of preparing the slag includes a process of preparing ferronickel slag generated in the process of manufacturing molten ferronickel steel, and the process of preparing the plastic for filling is polyethylene terephthalate (PET) with the high melting point plastic. ) may include the process of preparing

The process of preparing the molded article is a process of reacting at least one of an epoxy functional group and a maleic anhydride functional group of the compatibilizer with at least one of a hydroxyl group (-OH) and a carboxyl group (-COOH) of the polyethylene terephthalate (PET). may include

A molded article according to an embodiment of the present invention is a low-melting-point plastic; High melting point plastic having a melting point higher than 50 ℃ than the low melting point plastic; slag disposed to be dispersed in the form of particles in the low melting point plastic and the high melting point plastic; and a compatibilizer combined with the high melting point plastic.

The slag may contain 10 wt% or less of CaO based on the entire slag.

The slag may include at least one of blast furnace slag, steelmaking slag, and ferronickel slag, and the plastic may include waste plastic.

The particle size of the slag may be 0.01 to 0.15 mm.

The slag may include angled polyhedral particles.

The low melting point plastic includes at least one of polyethylene (PolyEthylene, PE), polypropylene (PolyPropylene, PP), polystyrene (PS) and polycarbonate (PolyCarbonate, PC), and the high melting point plastic is polyethylene terephthalate ( PET) may be included.

The compatibilizer may include at least one of an epoxy functional group and a maleic anhydride functional group.

The compatibilizer may be included in an amount of 1 to 5% by weight based on the entire high-melting point plastic.

According to the embodiment of the present invention, it is possible to manufacture a molded body having excellent mechanical properties by using slag generated in the ironmaking process and various types of waste plastics. Such a molded body can be used as a building material, a material for civil engineering, etc., and has excellent strength and corrosion resistance, and thus the durability and lifespan of a structure constructed using the molded body can be improved. In addition, since the compact can be manufactured by using a large amount of inexpensive and high-strength waste plastic, the strength of the compact can be further improved, and the manufacturing cost of the compact can be reduced. In addition, it is possible to effectively recycle various types of waste plastics by increasing the compatibility between waste plastics. Accordingly, it is possible to increase the recycling rate of waste plastics, thereby suppressing or preventing environmental pollution caused by waste plastics. Since the slag is surrounded by waste plastic and blocked from the outside or the surrounding environment, it is possible to prevent the leakage of harmful components from the slag and to prevent the surrounding environment from being polluted.

In addition, when extruding a mixture of slag and waste plastic to produce a molded body, it is possible to suppress a phenomenon in which the slag directly contacts the inner surfaces of the screw and the extruder body to abrade the screw and the extruder body. Therefore, it is possible to extend the life of the screw and the extruder body to extend the replacement or maintenance period, thereby reducing the cost of repairing or replacing the equipment.

1 is a view schematically showing a molded body manufacturing facility according to an embodiment of the present invention.
Figure 2 is a flowchart sequentially showing a process of manufacturing a molded body by the molded body manufacturing method according to an embodiment of the present invention.
3 is a flow chart sequentially showing a process of manufacturing a slag-plastic composite in the method for manufacturing a molded body according to an embodiment of the present invention.
4 is a cross-sectional view conceptually showing the internal structure of a molded body manufactured by the method for manufacturing a molded body according to an embodiment of the present invention.
5 is a view showing a reaction between PET and a compatibilizer in the method for manufacturing a molded body according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those of ordinary skill in the art completely It is provided to inform you. In the drawings, like reference numerals refer to like elements.

The present invention relates to a technology for manufacturing a product having excellent mechanical properties using slag generated in an ironmaking process, and waste plastics collected from household waste and industrial waste. Hereinafter, an example of manufacturing a molded body used as a building material, a civil engineering material, etc. from slag and waste plastic will be described. Here, the slag may contain a CaO component in an amount of 10% by weight or less based on the total weight of the slag. And the waste plastic may include a thermoplastic that melts when heat is applied, and changes back to a solid state when cooled. The waste plastic may include a plastic for coating to form a slag-plastic composite, and a plastic for filling for manufacturing a molded body together with the slag-plastic composite. Plastics for coating and plastics for filling may have different physical properties. For example, the plastic for coating and the plastic for filling may have different melting points, and the plastic for filling may include a high melting point plastic having a higher melting point than the plastic for coating. When a molded body is manufactured using plastics having mutual melting points as described above, the process of manufacturing the slag-plastic composite and the extrusion process of manufacturing the molded body can be performed at different temperatures. Therefore, it is possible to suppress or prevent wasted energy in the process of manufacturing the molded body, thereby further reducing the manufacturing cost of the molded body.

1 is a view schematically showing a molded article manufacturing facility according to an embodiment of the present invention.

Referring to FIG. 1 , the molded article manufacturing facility according to an embodiment of the present invention forms a plastic coating layer on the surface of the slag to form a slag-plastic composite, the coating part 100, and the slag-plastic composite and plastic are extruded and a control unit (not shown) for controlling the temperature of the molding unit 300 and the molding unit 300 to form the molded body (E). In addition, the molded body manufacturing facility according to an embodiment of the present invention may include a cutting unit 400 for cutting the molded body.

The coating unit 100 may form a slag-plastic composite by attaching a plastic, for example, a plastic for coating to the surface of the slag.

The coating unit 100 heats the slag and attaches a plastic for coating to the surface of the heated slag to form a slag-plastic composite with a coating machine 110 and a slag-cooler 120 that can cool the plastic composite ) may be included. In addition, the coating unit 100 may further include a crusher (not shown) capable of crushing the slag-plastic composite, if necessary.

The coating machine 110 includes a coating container 112 that forms a space that can accommodate slag and plastic for coating therein, and a first heating means 114 that can heat the space inside the coating container 112 can do. At this time, the coating container 112 may be rotatably formed to mix or stir the slag accommodated therein and the plastic for coating. For example, the coating vessel 112 may include a drum mixer that can be tilted to one side and rotated. The first heating means 114 may be formed in the coating container 112 to heat the coating container 112 . At this time, the first heating means 114 may heat the coating container 112 so that the slag accommodated in the coating container 112 can be heated to a temperature greater than or equal to the melting point of the plastic for coating. When the slag is introduced into the coating container 112 through this configuration, the slag can be heated to a temperature greater than or equal to the melting point of the plastic for coating by using the first heating means 114 while rotating the coating container 112 . And when the plastic for coating is put into the coating container 112, the plastic for coating is dissolved by the heat of the heated slag and is attached to the surface of the slag to form a slag-plastic composite.

The cooler 120 may cool the slag-plastic composite formed in the coating vessel 112 . The cooler 120 may include a cooling vessel 122 that forms a space capable of accommodating the slag-plastic composite, and a cooling means 124 capable of cooling the space inside the cooling vessel 122 . The cooling vessel 122 may be rotatably formed to flow the slag-plastic composite accommodated therein. For example, the cooling vessel 122 may include a drum mixer that can be tilted to one side and rotated like the coating vessel 112 . And the cooling means 124 may be formed in the cooling vessel 122 to cool the cooling vessel 122 . When the slag-plastic composite is discharged from the coating container 112 to the cooling container 122 through this configuration, the cooling container 122 is rotated to allow the slag-plastic composite to flow. Accordingly, the slag-plastic composite may be uniformly cooled while in contact with the inner wall of the cooling vessel 122 .

On the other hand, the slag-plastic composite may be formed by melting and attaching a plastic for coating to the surface of the slag. Accordingly, the slag-plastic composite is not formed in the form of particles, but the slag-plastic composite particles are agglomerated by the molten plastic to form a lump. However, in the process of cooling the slag-plastic composite, as the slag-plastic composite collides with each other, the slag-plastic composite mass may be crushed to form slag-plastic composite particles. However, the slag-plastic composite mass may not be separated into slag-plastic composite particles. Therefore, when the slag-plastic composite is cooled, if necessary, the slag-plastic composite mass may be crushed using a crusher and separated into particles.

The molding unit 300 may manufacture the molded body (E) by extruding the slag-plastic composite and the plastic for filling. The molding unit 300 includes an extruder body 312 that forms a space for accommodating the slag-plastic composite and the plastic for filling, and a screw 330 and the extruder body that are rotatably formed inside the extruder body 312 ( and a die 320 coupled to 312 . In addition, the molding unit 300 may include a second heating means 340 formed in the extruder body 312 to heat the slag-plastic composite accommodated in the extruder body 312 and the plastic for filling. And the molding unit 300 includes a mixing container (not shown) for uniformly mixing the slag-plastic composite and the plastic for filling before the slag-plastic composite and the plastic for filling are put into the extruder body 312. have.

The extruder body 312 is formed with a space capable of accommodating a slag-plastic composite, a plastic for filling and a compatibilizer or a mixture containing a slag-plastic composite, a plastic for filling, and a compatibilizer, and extends in one direction, for example, in a horizontal direction. It may be formed in a hollow shape. The extruder body 312 may be formed in a substantially cylindrical shape with both sides open, and an inlet 314 for injecting a slag-plastic composite, a plastic for filling and a compatibilizer or a mixture thereof may be formed on one upper portion. The injection port 314 may be formed in a funnel shape or a hopper shape so that the slag-plastic composite, plastic for filling, and compatibilizer or a mixture thereof can be easily injected into the extruder body 312 . At this time, the other side spaced apart from the inlet 314 in the extruder body 312 may be opened and used as an outlet 316 capable of discharging the mixture.

The die 320 may be connected to the outlet 316 of the extruder body 312, has an inner diameter smaller than the inner diameter of the extruder body 312, and may be formed in a hollow shape with both sides open. The inner space of the die 320 may be formed in various shapes so that the die 320 can form a molded body E having a desired shape by mixing a slag-plastic composite, a plastic for filling, and a compatibilizer. For example, when the molded body E is formed to have a rectangular plate shape, the inner space of the die 320 may be formed to have a rectangular slit cross-sectional shape. Alternatively, when the molded body E is formed to have a cylindrical bar shape, the inner space of the die 320 may be formed to have a circular cross-sectional shape.

The screw 330 may be disposed in the extruder body 312 along the direction in which the extruder body 312 extends. At this time, one side of the screw 330 may be rotatably connected to the open side of the extruder body 312 through a connection means 331 such as a bearing. In addition, the other side of the screw 330 may be arranged to extend to a connection portion between the extruder body 312 and the die 320 . The screw 330 is rotated by the driving of the actuator 332 provided in the extruder body 312 to move the mixture injected into the extruder body 312 toward the outlet 316 and through the die 320 to the extruder body ( 312) can be extruded to the outside.

The second heating means 340 may be formed in the extruder body 312 to heat the extruder body 312 . The second heating means 340 can heat the extruder body 312 to a temperature higher than the melting point of the plastic, for example, the plastic for filling, and the plastic, particularly the plastic for filling, can maintain a temperature above the melting point of the plastic, in particular, the plastic for filling in the extruder body 312. It may be formed along the longitudinal direction of the extruder body 312 so as to be.

The control unit controls the second heating means 340 to adjust the temperature of the extruder body 312 in the direction in which the extruder body 312 is extended or in the direction in which the slag-plastic composite, the plastic for filling, and the mixture of the compatibilizer are extruded. can That is, when the slag-plastic composite is injected into the extruder body 312 , if the temperature at the injection port 314 is too high, the plastic for coating on the surface of the composite may be rapidly melted. In this case, the slag forming the slag-plastic composite is exposed, and as the screw 330 rotates, it may come into contact with the screw 330 and the extruder body 312 . Due to this, the inner surface of the screw 330 and the extruder body 312 may be worn. In addition, when the slag forming the slag-plastic composite is exposed, the slag and the molten filling plastic are separated into solid-liquid due to the difference in specific gravity between the slag and the filling plastic, so that the slag cannot be uniformly dispersed in the molten filling plastic. may be Therefore, the control unit can control the second heating means 340 to adjust the temperature at the outlet 316 side at which the mixture is extruded higher than the temperature at the injection port 314 side through which the mixture is injected in the extruder body 312 . Alternatively, the controller may control the second heating means 340 so that the temperature increases from the extruder body 312 toward the outlet 316 through which the mixture is extruded from the injection port 314 side through which the mixture is injected. Through this, it is possible to delay the melting point of the plastic for coating constituting the slag-plastic composite. Therefore, the time during which the slag of the slag-plastic composite comes into contact with the inner surfaces of the screw 330 and the extruder body 312 is shortened, thereby reducing the abrasion of the inner surfaces of the screw 330 and the extruder body 312 . In addition, by uniformly dispersing the slag or the slag-plastic composite in the molten plastic for filling, it is possible to improve the quality of the molded article to be manufactured.

Through this configuration, the mixture is injected into the extruder body 312 and then moves along the inside of the extruder body 312 by the rotation of the screw 330 and is extruded through the die 320 to the outside of the extruder body 312 to form a molded body (E) can be prepared. In this case, the mixture may be heated to a temperature higher than the melting point of the plastic by the second heating means 340 . When the mixture is heated in this way, the plastic component in the mixture is dissolved to form a plastic melt, and the slag can be uniformly dispersed in the melt of the molten plastic, such as a plastic for filling.

The molding unit 300 may continuously form the molded body (E) by extruding the mixture. The molded body (E) thus formed may be cut to have a predetermined length or a desired length by the cutting part 400 . The cut portion 400 may be disposed to be spaced apart from the extruder body 312 in the front of the extruder body 312, or in front of the die 320 in the direction in which the molded body is discharged.

Hereinafter, a method for manufacturing a molded body according to an embodiment of the present invention will be described.

2 is a flowchart sequentially showing a process of manufacturing a molded body by the method for manufacturing a molded body according to an embodiment of the present invention, and FIG. 3 is a slag-plastic composite manufacturing process according to the embodiment of the present invention. 4 is a cross-sectional view conceptually showing the internal structure of a molded body manufactured by the method for manufacturing a molded body according to an embodiment of the present invention.

Referring to FIG. 2 , the method for manufacturing a molded body according to an embodiment of the present invention includes a process for preparing slag (S110), a process for preparing a plastic for coating (S112), and a plastic for filling that has a higher melting point than the plastic for coating. The process of preparing (S114), the process of manufacturing a slag-plastic composite using the slag and the plastic for coating (S120), and the process of extruding a mixture containing the slag-plastic composite and the plastic for filling to manufacture a molded body ( S130) may be included. In addition, the method for manufacturing a molded body according to an embodiment of the present invention may include a process (S116) of preparing a compatibilizer for mixing the plastic for coating and the plastic for filling. In this case, in the process of manufacturing the molded body ( S130 ), a mixture of the slag-plastic composite and the plastic for filling and a compatibilizer may be extruded.

The slag may be prepared to produce a slag-plastic composite. In this case, the slag may include various slags generated in the ironmaking process, and may contain CaO in an amount of 10 wt% or less. Alternatively, the slag may contain CaO in an amount of 0 wt% to 5 wt%, or 0.01 to 2.0 wt%. Such slag may include ferronickel slag generated in the process of manufacturing ferronickel molten steel. Alternatively, the slag may include slag whose composition is adjusted to contain 10% by weight or less of CaO by mixing ferro nickel slag, blast furnace slag, converter slag and electric furnace slag, or by mixing a separate auxiliary material with the slag. may be In this case, the smaller the CaO content contained in the slag, the better.

Table 1 below shows the content of main components according to the type of slag.

Blast Furnace Slag steel slag Furnace Slag (oxidation) Furnace slag (reduction) ferronickel slag CaO (wt%) 41.8 46.1 13.85 44.96 0.28 SiO ₂ (wt%) 33.50 41.8 17.57 23.21 54.7 Al ₂ O ₃ (wt%) 13.6 1.5 7.45 12.98 1.93 MgO (wt%) 6.4 6.3 5.15 9.90 33.1 Other (wt%) 4.7 4.3 55.98 8.95 9.99

As shown in Table 1, it can be seen that the CaO content of ferronickel slag is very small compared to blast furnace slag, steelmaking slag, and electric furnace slag. Since CaO has a property of absorbing moisture, when a slag-plastic composite is manufactured using blast furnace slag, steelmaking slag, and electric furnace slag containing a large amount of CaO, or when a molded body is manufactured, Moisture evaporation occurs. The evaporated moisture in this way generates bubbles in the slag-plastic composite or molded body, thereby reducing the strength of the slag-plastic composite or molded body. Therefore, a slag-plastic composite can be prepared by using ferronickel slag containing less CaO component compared to other slags alone, and a high-strength molded body can be manufactured using the slag-plastic composite. Alternatively, ferronickel slag, blast furnace slag, converter slag and electric furnace slag are mixed to contain 10 wt% or less of CaO with respect to the total weight of the slag, and the composition of the slag is adjusted, and then it can be used to prepare a molded article. Alternatively, a separate auxiliary material is mixed with at least one slag of ferronickel slag, blast furnace slag, converter slag and electric furnace slag so as to contain 10 wt% or less of CaO based on the total weight of the slag, and then the composition of the slag is adjusted It can also be used to manufacture molded articles. In other words, the slag used in the compact can be prepared by mixing slags having different CaO contents with each other. At this time, by mixing slag having a high CaO content and slag having a low CaO content, the CaO content may be adjusted to 10% by weight or less. Alternatively, by mixing slag having a CaO content of more than 10% by weight and _{an auxiliary material containing a large amount of SiO 2} , the slag having a CaO content adjusted to 10% by weight or less may be used for manufacturing the molded body. For example, 10% by weight of blast furnace slag and 90% by weight of ferronickel slag are mixed with ferronickel slag based on the total weight of the blast furnace slag and ferronickel slag, and a slag-plastic composite can be prepared using the mixture. Alternatively, 15% by weight of electric furnace slag (oxidation) and 85% by weight of ferronickel slag are mixed with respect to the total weight of the combined electric furnace slag (oxidation) and ferronickel slag, and using this, a slag-plastic composite can be prepared. can In this case, it is easy to control the CaO content by mixing electric furnace slag (oxidation) with less CaO content than blast furnace slag or steelmaking slag with ferronickel slag. As described above, a slag-plastic composite may be manufactured using various slags generated in the ironmaking process, and a molded body may be manufactured by extruding the manufactured slag-plastic composite and plastic. Hereinafter, an example of manufacturing a molded body using ferronickel slag will be described.

Ferronickel slag has a very small content of CaO compared to other slags, and has a very high hardness (Mohs hardness) of 7 to 7.5 Mohs. In addition, as shown in FIG. 4, ferronickel slag is a polyhedral particle with angular ridges, and the particle shape is very irregular. When a molded article is manufactured using such ferronickel slag, the contact area between the slag particles or between the slag particles and the plastic for coating increases compared to slag having a spherical particle shape. Through this, the density of the ferronickel slag in the molded body is increased, and thus a high-strength molded body having excellent mechanical properties can be manufactured. In an embodiment of the present invention, an example in which ferronickel slag is used as slag used as a raw material for a molded body will be described, and ferronickel slag is called slag hereinafter.

The particle size of the slag can be selected to prepare a slag-plastic composite. Slag generated in the process of manufacturing ferronickel molten metal can be crushed. When the slag is crushed, 90% or more of the slag has a particle size of 6 mm or less. Among them, slag having a particle size of about 0.01 to 0.15 mm or 0.05 to 0.1 mm can be selected and used as a raw material for the slag-plastic composite. In this case, the smaller the particle size of the slag, the better, but if the particle size of the slag is processed too small, the cost for crushing the slag may increase. On the other hand, when the particle size of the slag exceeds 0.15 mm, since it is difficult to sufficiently secure a contact area between the slag and the plastic, there is a problem in that it is difficult to sufficiently improve the strength of a molded article manufactured using the same.

Plastics used as raw materials for the molded body, such as plastics for coating and plastics for filling, may be provided. Plastics may include thermoplastics that melt when heated and change back to a solid state when cooled. In this case, the plastic may include PET, polyethylene (hereinafter, referred to as PE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and the like. Here, the polyethylene may include high-density polyethylene (HDPE) and low-density polyethylene (LDPE). Such plastics may include waste plastics collected from domestic and industrial waste. Collected plastics, such as waste plastics, can be washed to remove impurities, and then classified into plastics for coating and plastics for filling. In this case, the waste plastic may be classified into a plastic for coating and a plastic for filling according to the physical properties of the waste plastic, for example, a melting point. Waste plastics can be classified into high melting point plastics having the highest melting point among waste plastics and low melting point plastics having a lower melting point than high melting point plastics. For example, among the above-mentioned plastics, PET having a melting point of about 240° C. may be classified as a high melting point plastic, and PE, PP, etc. having a melting point of about 130° C. may be classified as a low melting point plastic. And the high melting point plastic may be used as a filling plastic, some of the low melting point plastics may be used as a coating plastic, and some of the low melting point plastics may be used as a filling plastic. In this case, the low-melting-point plastic may include a plurality of types of waste plastics except for waste plastics having the highest melting point among waste plastics, for example, PET. By classifying waste plastics in this way and excluding high-melting-point plastics from plastics for coating, energy can be efficiently used in manufacturing the molded body. That is, if the waste plastics are not classified as described above, since high-melting-point plastics can be used in the process of manufacturing the slag-plastic composite and in the extrusion process, all of these processes must be performed at a temperature higher than the melting point of the high-melting-point plastics. However, if the plastic for coating is excluded as a high-melting-point plastic, the process of manufacturing the slag-plastic composite is performed at a lower temperature than the extrusion process because the plastic for coating has a melting point that is 50°C or more or 100°C or more lower than that of the filling plastic. can do. Accordingly, if the plastic for coating and the plastic for filling have a large melting point difference, at least the manufacturing process of the slag-plastic composite can be performed at a lower temperature, and thus energy can be efficiently used in manufacturing the molded body. In addition, PET among waste plastics may be classified as a high melting point plastic. PET is relatively inexpensive compared to other waste plastics, and has excellent strength and chemical resistance. Therefore, when PET is used as a filling plastic, since PET can be used in a large amount, the strength of the molded body can be improved, and the manufacturing cost of the molded body can be reduced.

After classifying the waste plastic into a low-melting-point plastic and a high-melting-point plastic, the low-melting-point plastic and the high-melting-point plastic can be crushed, respectively. In this case, the low-melting-point plastic and the high-melting-point plastic may be crushed to have a size of 5 mm or less or about 1 to 4 mm, respectively, or have a size of about 2 to 3 mm. The size of the crushed plastic, that is, the crushed low-melting-point plastic and the crushed high-melting-point plastic, may be 5 mm or less in the largest part of width, length, and thickness. If the size of the crushed plastic is too small, when the crushed plastic is added to the coating container 112 or the extruder body 312, it scatters, or the weight or specific gravity difference with the slag increases, so that it is easily mixed with the slag or slag-plastic composite it may not be On the other hand, when the size of the plastic is too large, the slag, the plastic for coating, and the slag-plastic composite and the plastic for filling may not be uniformly mixed. In addition, when the slag-plastic composite is manufactured, the plastic for coating is not easily melted, and the contact frequency or contact area between the slag and the plastic for coating is reduced, making it difficult to sufficiently coat the surface of the slag. Therefore, by crushing the plastic to an appropriate size, so that the slag and the plastic for coating can be uniformly mixed, and by increasing the contact frequency or contact area with the slag, the slag can be smoothly coated with the plastic for the coating.

After crushing the plastic, a portion of the low-melting-point plastic may be provided as a plastic for coating, and a portion of the low-melting-point plastic and the high-melting-point plastic may be provided as a plastic for filling. Alternatively, the entire filling plastic may be used as a high melting point plastic, such as PET. In this case, the high melting point plastic and the low melting point plastic may be stored in separate storage places, or the low melting point plastic and the high melting point plastic may be mixed and stored in a separate storage place. As described above, only the high-melting-point plastic may be used as the filling plastic, but a mixture of a low-melting-point plastic and a high-melting-point plastic may be used as the filling plastic. In this case, when the high melting point plastic is PET, more PET than the low melting point plastic such as PE or PP may be used. For example, PET may account for 50 wt% or more, or 60 to 90 wt% with respect to the entire plastic for filling. This is because PET is cheaper than low-melting-point plastics such as PE and PP and has high strength, so that the manufacturing cost of the molded body can be reduced and the strength of the molded body can be further improved. In addition, by recycling various types of waste plastics, it is possible to reduce environmental pollution caused by incineration or landfilling of waste plastics.

In an embodiment of the present invention, a molded body may be manufactured by melt-extruding two or more waste plastics having different physical properties at a high temperature. At this time, since the waste plastics have different physical properties, there is a problem in that they do not mix with each other during extrusion. For example, PET and PE do not mix well like water and oil because PET has hydrophilicity and polyethylene (PE) has hydrophobicity. Accordingly, when PET and PE are melt-extruded, PET and PE do not mix well, and an interface may be formed between PET and PE in a molded article manufactured using them. Therefore, the molded body is prone to cracks or to be destroyed by external force. In order to solve this problem, a compatibilizer that allows waste plastics having different physical properties to mix well with each other, ie, can be uniformly mixed, may be used when manufacturing a molded body. That is, when a molded body is manufactured using plastics having different physical properties, such as PET and PE, a compatibilizer is not used, PET and PE are not uniformly mixed, and PET and PE form a lump, respectively, so that PET and PE An interface can be formed between them. However, if a compatibilizer is used when manufacturing a molded article using PET and PE, since PET reacts with the compatibilizer and is modified to have properties similar to PE, an interface between PET and PE is not formed and can be mixed uniformly. .

The compatibilizer is used to mix well when high molecular substances having different physical properties are dissolved, and can act like a surfactant to mix well with water and oil. In an embodiment of the present invention, a compatibilizing agent for well mixing waste plastics such as PET having hydrophilicity and waste plastics such as PE and PP having hydrophobicity may be used. Accordingly, the compatibilizer may further increase the strength of the molded article by suppressing the formation of an interface between different types of plastics when the molded article is cooled. The compatibilizer may include an epoxy functional group and a maleic anhydride functional group. Here, the compatibilizer including an epoxy functional group is ethylene/glycidyl metaacrylate copolymer (E/GMA), ethylene/ethyl acrylate/glycidyl methacrylate terpolymer (ethylene/ethyl acrylate/glycidyl metaacrylate terpolymer (E/EA/GMA) and ethylene/methyl acrylate/glycidyl meta acrylate terpolymer (E/MA/GMA). And the compatibilizing agent comprising a maleic anhydride functional group is hydrogenated styrene/butadiene/styrene copolymer grafted with maleic anhydride (SEBS-g-MA), maleic It may include maleic anhydride modified ethylene/methyl acrylate copolymer (E/MeA-g-MA). The epoxy functional group and the maleic anhydride functional group of the compatibilizer may react with at least one of a hydroxyl group (-OH) and a carboxyl group (-COOH) contained in the waste plastic. As such, PET is a waste plastic having a hydroxyl group (-OH) and a carboxyl group (-COOH) capable of reacting with an epoxy functional group and a maleic anhydride functional group. Therefore, the amount of the compatibilizer to be used may be determined according to the amount of PET used for manufacturing the molded article. Since PET is contained in the plastic for filling, the compatibilizer may be used in an amount of 1 to 5% by weight or 2 to 3% by weight based on the total weight of PET contained in the plastic for filling. If the amount of the compatibilizer is too small, the PET may not react sufficiently with the compatibilizer, so that the PET melt and other low-melting point plastics are not uniformly mixed, and thus the strength of the molded article may be lowered. On the other hand, if the amount of the compatibilizer is too large, the compatibilizer remaining after reacting with PET aggregates in the molded body to form a lump. Accordingly, an interface may be formed between the plastic and the compatibilizer mass in the molded body, thereby reducing the strength of the molded body.

When the slag, the plastic for coating, the plastic for filling, and the compatibilizer are prepared as described above, a molded body can be manufactured using these.

First, a slag-plastic composite may be manufactured using slag and a plastic for coating.

Referring to FIG. 3 , the process of manufacturing the slag-plastic composite includes a process of heating the slag (S121), a process of injecting and mixing plastic for coating into the heated slag (S122), and a process for coating the slag surface It may include a process of manufacturing a slag-plastic composite by attaching a plastic (S123) and a process of cooling the slag-plastic composite (S124). In addition, if necessary, the process of crushing the cooled slag-plastic composite (S125) may be performed.

First, the slag may be put into the coating container 112 , and the slag may be heated using the first heating means 114 ( S121 ). The slag can be uniformly heated by rotating the coating container 112 while heating the slag to evenly contact the slag with the inner wall of the coating container 112 . At this time, the slag is higher than the melting temperature of the plastic for coating, and may be heated to a temperature lower than the temperature at which the plastic for coating is burned. The heating temperature of the slag may vary depending on the type of coating plastic used to prepare the slag-plastic composite, but most plastics except PET melt at 200°C or less, so the slag is heated to 200°C or less or 150 to 180°C. can be For example, the melting point of PE and PP is about 130 ℃, and the melting point of PET is about 240 ℃. Therefore, when the slag is heated to a temperature of 200° C. or less, all plastics except PET can be melted. Here, if the heating temperature of the slag is too low, the plastic for coating may not melt and may not adhere to the surface of the slag. In this case, there is a problem in that the plastic for coating is attached only to a part of the surface of the slag, or the plastic for coating is not attached to the surface of the slag at all, so that the manufacturing efficiency of the slag-plastic composite is lowered. On the other hand, when the heating temperature of the slag is too high, the plastic for coating is burned or carbonized, so that the slag-plastic composite cannot be manufactured.

When the slag is heated to a temperature greater than or equal to the melting point of the plastic for coating, the plastic for coating may be added to the coating container 112 and mixed with the slag (S122). Based on the total weight of the slag and the plastic for coating, the slag may be added in an amount of 90 to 95% by weight, and the plastic for coating may be added in an amount of 5 to 10% by weight. If the amount of the coating plastic is too small, the surface of the slag cannot be sufficiently coated. Accordingly, there is a problem in that the slag is in direct contact with the inner surface of the extruder body 312 and the screw 330 in the process of extruding the slag-plastic composite, thereby abrading the inner surface of the extruder body 312 and the screw 330 . On the other hand, if the input amount of the plastic for coating is too large, the plastic for coating may remain as a lump after the slag-plastic composite is manufactured, or the slag-plastic composite may become agglomerated with each other. In this case, since the slag-plastic composite is not uniformly dispersed in the molded body during manufacturing of the molded body, a separate crushing process must be performed (S125) to make the slag-plastic composite into particle form, thereby complicating the process.

As such, when the coating plastic is put into the coating container 112, the coating container 112 can be rotated to bring the heated slag into contact with the coating plastic. Accordingly, the plastic for coating is melted by the heat of the heated slag and adhered to the surface of the slag, whereby a slag-plastic composite may be manufactured (S123). That is, as shown in FIG. 1 , a slag-plastic composite in which a plastic coating layer (C) is formed on the surface of the slag (S) can be manufactured.

When the slag-plastic composite is manufactured, the high-temperature slag-plastic composite may be put into the cooling vessel 122 to be cooled (S124). At this time, when the cooling vessel 122 is rotated, the high-temperature slag-plastic composite may be uniformly cooled while contacting the inner surface of the cooling vessel 122 cooled by the cooling means 124 . In addition, as the cooling vessel 122 rotates, since the slag-plastic composite collides with each other, the slag-plastic composite attached to each other is broken, and the slag-plastic composite may be formed in the form of particles.

Thereafter, the cooled slag-plastic composite, the plastic for filling, and the compatibilizer may be extruded to manufacture a molded body (S130).

In order to manufacture the compact, a slag-plastic composite, which is a raw material for the compact, a plastic for filling, and a compatibilizer may be prepared in a predetermined amount. Based on the total weight of the slag-plastic composite and the plastic for filling, the slag-plastic composite may be prepared in an amount of 30 to 80% by weight, and the plastic for filling may be prepared in an amount of 20 to 70% by weight. Alternatively, based on the total weight of the slag-plastic composite and the plastic for filling, the slag-plastic composite may be prepared in an amount of 40 to 60% by weight, and the plastic for filling may be prepared in an amount of 40 to 60% by weight. In this case, with respect to the total weight of the slag-plastic composite and the plastic for filling, 27 to 76% by weight of slag, 14 to 73% by weight of plastic for filling may be included. When the content of the slag is too small, the content of the plastic for filling, which has a lower strength than that of the slag, is relatively increased, so that the mechanical strength of a molded article manufactured using the content cannot be sufficiently secured. On the other hand, when the content of the slag is excessively large, the content of the plastic for filling that binds the slag is relatively decreased, so that the bonding force between the slags may be reduced. The content of the slag-plastic composite and the plastic for filling may vary depending on the use of the molded article to be manufactured. For example, when the molded article is used for a purpose requiring high impact strength, the content of the plastic for filling may be higher than the content of the slag-plastic composite. On the other hand, when the molded article is used for a purpose requiring high flexural strength, the content of the slag-plastic composite may be adjusted to be higher than that of the plastic for filling.

On the other hand, the specific gravity of the slag is about 2 to 3, and the specific gravity of the plastic, for example, plastic for coating or plastic for filling is about 0.8 to 0.95. In addition, the molded article manufactured using the slag and the plastic may have a specific gravity smaller than that of the slag and greater than that of the plastic, for example, about 1 to 2 specific gravity. Therefore, the mixing ratio of the slag and the plastic can be appropriately adjusted according to the intended use of the molded body. For example, when the compact is used as a wet flooring material, the effect of buoyancy caused by rain can be reduced by increasing the specific gravity of the compact by increasing the content of slag.

The compatibilizer may be provided in an amount of 1 to 5% by weight, or 2 to 3% by weight based on the total PET contained in the plastic for filling. If the amount of the compatibilizer is too small, the PET and the low-melting-point plastic, such as the low-melting-point plastic contained in the plastic for filling and the plastic for coating of the slag-plastic composite, may not be uniformly mixed during extrusion, so that the strength of the molded article may be lowered. On the other hand, if the amount of the compatibilizer is too large, some of it is used to react with PET, but some may aggregate in the molded body to form an interface with the plastic, so there is a problem in that the strength of the molded body is lowered.

In addition, in addition to the slag-plastic composite and the plastic for filling, additives such as colorants and UV stabilizers may be additionally used according to the use of the molded article. For example, when a color is given to the molded article for aesthetics, a colorant may be further used, and when the molded article is used in a portion exposed to sunlight, a UV stabilizer may be further used. In this case, the additive may be used in an amount of 0.01 to 0.05 parts by weight when the entire molded body is 1. When the content of the additive is too small, the effect of the additive cannot be sufficiently exhibited. On the other hand, when the content of the additive is too large, the cost due to the use of the additive increases, and the content of the additive in the molded article increases, thereby reducing the strength of the molded article.

When the raw material of the molded body is prepared in this way, the prepared raw material, that is, the slag-plastic composite, the plastic for filling and the compatibilizer or the slag-plastic composite, the plastic for the filling, the compatibilizer and the additive may be injected into the extruder body 312 . At this time, the raw material may be mixed in a separate mixing container before injecting the extruder body 312, and then the mixture in which each raw material is mixed may be injected into the extruder body 312, and each raw material may be injected into the extruder body 312 ) can also be injected independently. As the raw material moves inside the extruder body 312 , the plastic among the raw materials may be melted by the second heating means 340 . The extruder body 312 may be heated by the second heating means 340 before the raw material is injected. At this time, the extruder body 312 may be heated to a temperature higher than the temperature of the coating container 112 when manufacturing the slag-plastic composite, for example, about 100° C. This is because the filling plastic used for manufacturing the molded body includes a high melting point plastic such as PET. The extruder body 312 may be heated to a temperature higher than the melting point of PET, eg, 250° C. or higher. At this time, the injection port 314 side into which the raw material is injected in the extruder body 312 may be heated to about 250 to 280°C, and the side where the raw material is extruded may be heated to about 300 to 320°C. This is because, if the inlet 314 side temperature is too high, the plastic for coating in the slag-plastic composite is easily melted. When the plastic for coating is melted easily or quickly in this way, the slag is exposed and comes into direct contact with the extruder body 312 and the screw 330 , which may cause the extruder body 312 and the screw 330 to be worn. Therefore, it is possible to prevent the slag from abrading the extruder body 312 and the screw 330 by increasing the temperature of the extruder body 312 along the moving direction of the raw material to delay the dissolution of the plastic for coating.

When the raw material or mixture is injected into the extruder body 312, the screw 330 is operated to extrude the raw material to manufacture a molded body. In this case, the screw 330 may be operated before the raw material is injected into the extruder body 312 , or may be operated simultaneously with the raw material injected into the extruder body 312 . When injecting the raw material into the extruder body 312 in this way, the slag is in direct contact with the inner surface of the extruder body 312 and the screw 330 during raw material extrusion by coating and injecting the slag among the raw materials with a plastic for coating in advance. can be prevented That is, slag, for example, ferronickel slag is a material with very high hardness, and when in direct contact with the extruder body 312 and the screw 330 , there is a problem of abrasion of the extruder body 312 and the screw 330 . Therefore, when the surface of the slag is coated with a plastic for coating and injected into the extruder body 312 in a slag-plastic composite state, the phenomenon that the slag wears the extruder body 312 and the screw 330 can be suppressed or prevented. Accordingly, by improving the durability of the extruder body 312 and the screw 330, it is possible to extend their repair or replacement period. In addition, when the surface of the slag is coated or covered with a plastic for coating and extruded together with a plastic for filling and a compatibilizer, the difference in specific gravity between the slag and the plastic for filling is reduced, thereby suppressing the separation of the slag from the plastic for filling during extrusion. and the slag can be uniformly dispersed in the plastic for filling.

Meanwhile, in the mixture, the plastic for coating and the plastic for filling may be melted while moving along the inside of the extruder body 312 . At this time, the plastic for coating and the plastic for filling may be uniformly mixed with each other by the compatibilizer. PET contained in the filling plastic reacts with the compatibilizer to form a reactant. PET has a hydroxyl group (-OH) and a carboxyl group (-COOH), and the epoxy functional group or maleic anhydride functional group of the compatibilizer may react with the hydroxyl group and carboxyl group of PET to form a reactant.

5 is a view showing a reaction between PET and a compatibilizer in the method for manufacturing a molded article according to an embodiment of the present invention. For example, when the compatibilizer has an epoxy functional group, the epoxy functional group of the compatibilizing agent reacts with a hydroxyl group of PET as shown in FIG. 5(a), and reacts with a carboxyl group of PET as shown in FIG. will form Through this reaction, PET can be modified to a state that can be mixed well with plastics having different physical properties, such as high-density polyethylene. Therefore, while PET is being extruded, it can be uniformly mixed with other low-melting plastics and evenly distributed in the molded body. Through this action, the strength of the molded body may be further improved.

By continuously injecting the raw material into the extruder body 312 and passing the die 320 connected to the extruder body 312, it is possible to continuously manufacture a molded body. At this time, the raw material may be extruded by moving toward the die 320 while being sufficiently mixed inside the extruder body 312 . When extruding the mixture in this way, the plastic for the filling, as well as the plastic for the coating of the slag-plastic composite may be melted together. However, since the plastic for coating of the slag-plastic composite is attached to the slag, a phenomenon in which it is not completely separated from the slag may occur. Therefore, in the molded body extruded from the die 320, plastics for cozine, such as low-melting plastics, are mainly located around the slag, and low-melting-point plastics and high-melting plastics are mixed on the outside of the low-melting-point plastics. It may be located. That is, a mixture of a low-melting-point plastic and a high-melting-point plastic may be positioned between the slag particles, and a low-melting-point plastic may be positioned between the slag particles, and a mixture of the low-melting-point plastic and the high-melting plastic.

When the molded body is extruded through the die 320 , the molded body may be cut to a predetermined length or a target length using the cutting unit 400 after cooling the molded body. The shape of the molded body or product may be variously changed according to the inner shape of the die 320 . In this way, the molded body can be mass-produced using slag and plastic.

The molded article thus produced may include two or more plastics having different physical properties, such as melting points, and slag disposed to be dispersed in the form of particles in the plastic. At this time, the slag may contain 10 wt% or less of CaO with respect to the entire slag. In addition, the molded body may have a structure in which plastics for cozine, such as low-melting-point plastics, are mainly located around the slag, and low-melting-point plastics and high-melting-point plastics are located on the outside of the low-melting-point plastics in a mixed state.

Here, a method for manufacturing a molded body by extruding a raw material through the die 320 has been described, but a separate mold (not shown) is connected to the die 320, and the extruded raw material, such as an extrudate, is injected into the mold. It is also possible to manufacture molded articles or products of various shapes.

When the molded body is manufactured in this way, the extruder body 312 and the screw 330 are prevented from being abraded by the slag, thereby improving the durability and service life of the extruder body 312 and the screw 330 . In addition, by manufacturing high value-added products such as building materials and civil engineering materials using waste slag and waste plastics, it is possible to reduce environmental pollution caused by waste and reduce construction costs. In particular, since a large amount of PET, which is provided at a relatively low price, can be used, it is possible to reduce the cost for manufacturing the molded body.

Hereinafter, an experimental example for verifying the mechanical properties of the molded body manufactured by the method for manufacturing the molded body according to an embodiment of the present invention will be described.

Ferronickel slag, waste plastic, and compatibilizer were prepared in order to prepare a molded body. At this time, the ferronickel slag was prepared to have an average particle size of 0.15 mm or less. Waste plastic was prepared by crushing waste vinyl containing PET and high-density polyethylene (HDPE), respectively, to have a thickness of 100 to 200 μm and a length or width of 2 mm or less. And as the compatibilizer, an ethylene/glycidyl methacrylate copolymer including an epoxy functional group was used.

Experimental Example 1

After putting 190 g of ferronickel slag into a coating container and heating it to about 170 to 180° C., 10 g of high-density polyethylene was added to the coating container. Then, the slag-plastic composite was prepared by stirring for 10 minutes so that the high-density polyethylene was uniformly attached to the ferronickel slag, and then cooled.

Then, 200 g of the slag-plastic composite, 100 g of PET, 100 g of high-density polyethylene, and 2 g of a compatibilizer were injected into the extruder body and extruded to prepare a molded body. At this time, the inlet side temperature of the extruder body was maintained at 260 to 280 ℃, the die side temperature was maintained at 300 to 320 ℃. And the manufactured molded body was processed to a size suitable for strength measurement, and cooled.

Experimental Example 2

A slag-plastic composite was prepared in the same manner as in Experimental Example 1, and 200 g of the slag-plastic composite, 150 g of PET, 150 g of high-density polyethylene, and 3 g of compatibilizer were injected into the extruder body. And a molded article was prepared in the same manner as in Experimental Example 1.

Experimental Example 3

A slag-plastic composite was prepared in the same manner as in Experimental Example 1, and 200 g of the slag-plastic composite, 200 g of PET, 200 g of high-density polyethylene, and 4 g of a compatibilizer were injected into the extruder body. And a molded article was prepared in the same manner as in Experimental Example 1.

Experimental Example 4

A slag-plastic composite was prepared in the same manner as in Experimental Example 1, and 200 g of the slag-plastic composite, 100 g of PET, 100 g of high-density polyethylene, and 5 g of compatibilizer were injected into the extruder body. And a molded article was prepared in the same manner as in Experimental Example 1.

Experimental Example 5

A slag-plastic composite was prepared in the same manner as in Experimental Example 1, and 100 g of the slag-plastic composite, 100 g of PET, and 100 g of high-density polyethylene were injected into the extruder body. And a molded article was prepared in the same manner as in Experimental Example 1.

Experimental Example 6

190 g of ferronickel slag, 100 g of PET, 110 g of high-density polyethylene, and 2 g of compatibilizer were directly injected into the extruder body and extruded to prepare a molded body. Extrusion conditions were the same as in Experimental Example 1. And the manufactured molded body was processed to a size suitable for strength measurement, and cooled.

The flexural strength and impact strength of each of the molded articles prepared by Experimental Examples 1 to 6 were measured. Flexural strength was measured according to KS M ISO 178, and impact strength was measured according to KS M ISO 179-1. Table 2 below shows the results of measuring the flexural strength and impact strength of each molded article.

Ferronickel slag content (g) Plastic content (g) Compatibilizer content (g) complex
formation flexural strength
(MPa) impact strength
(kj/㎡) For coating (PE) For filling (PET/PE) Experimental Example 1 190 10 (100/100) 2 ○ 46.2 4.5 Experimental Example 2 190 10 (150/150) 3 ○ 2.3 5.1 Experimental Example 3 190 10 (200/200) 4 ○ 40.1 5.6 Experimental Example 4 190 10 (100/100) 5 ○ 30.6 3.5 Experimental Example 5 190 10 (100/100) 0 ○ 20.3 2.0 Experimental Example 6 190 0 (100/110) 2 × 18.2 2.3

Referring to Table 2, Experimental Examples 1 to 5, in which a slag-plastic composite was prepared using slag and a plastic for coating, and a molded body was prepared using this, in Experimental Example 6 in which a molded body was prepared without coating the slag with plastic. In comparison, it can be seen that the flexural strength and impact strength of the molded article were significantly higher. This is because, in the case of Experimental Examples 1 to 5, a coating layer was formed by attaching a plastic to the surface of the slag. That is, when the slag-plastic composite and the plastic for filling are extruded, the slag-plastic composite and the plastic for filling are not separated from each other and well maintained in a mixed state. In addition, as the plastic is melted, bonding force between the plastics may be promoted. For this reason, it is judged that the molded articles manufactured by Experimental Examples 1 to 5 exhibited higher flexural strength and impact strength compared to the molded articles produced by Experimental Example 6. However, in the case of Experimental Example 6, it is judged that the slag and the plastic having different components and different specific gravity did not exhibit sufficient flexural strength and impact strength because they were not easily separated or combined with each other as they were extruded. In particular, comparing Experimental Example 1 and Experimental Example 6, in which a molded article was prepared with the same composition, Experimental Example 1, in which a molded article was manufactured using a slag-plastic composite, was produced without forming a slag-plastic composite Experimental Example 6 It can be seen that the flexural strength and impact strength were measured more than twice as high compared to the flexural strength.

In addition, according to Experimental Examples 1 to 3, when a molded body is manufactured using a slag-plastic composite, it can be seen that the flexural strength and impact strength of the molded body can be adjusted according to the amount of plastic, for example, the amount of plastic for filling. . By controlling the amount of plastic for filling according to the intended use of the molded article, a molded article having a strength suitable for the intended use can be manufactured.

On the other hand, in Experimental Examples 1 to 4, the flexural strength and impact strength of the molded article were measured to be higher than those of Experimental Example 5. This is believed to be due to the use of compatibilizers. That is, in the case of Experimental Examples 1 to 4 using the compatibilizer, the flexural strength and impact strength were higher than those of Experimental Example 5 without using the compatibilizer. Through this, it can be seen that when a molded body is manufactured using two or more plastics having different physical properties, when a compatibilizer is used, the different plastics are uniformly mixed to increase the strength of the molded body. However, although the compatibilizer was used in Experimental Example 4, it is shown that the flexural strength and impact strength were lower than those of Experimental Examples 1 to 3. In the case of Experimental Examples 1 to 3 in which the compatibilizer was constantly used for the content of plastic for filling, particularly PET, the flexural strength of the molded article had a difference of about 2 to 4 MPa, and the impact strength had a difference of about 0.5 to 0.6. was measured. However, it can be seen that the flexural strength and impact strength of the molded article were significantly lower in Experimental Example 4 using an amount of the compatibilizer 2.5 times higher than in Experimental Example 1, in which the molded body was manufactured using the same amount of slag and plastic. This is because, when the content of the compatibilizer exceeds an appropriate amount, a part is used to react with PET, but a part is not uniformly mixed with the plastic in the molded body and aggregates to form an interface with the plastic.

And in the case of Experimental Example 6, although a compatibilizer was used in manufacturing the molded article, the flexural strength was measured to be low and the impact strength was measured to be high compared to Experimental Example 5 in which the compatibilizer was not used. Through this, it can be seen that when a molded body is manufactured using plastics having different physical properties from slag, the strength of the molded body can be improved by appropriately using a slag-plastic composite and a compatibilizer.

Combining the above results, it can be seen that mechanical properties such as flexural strength and impact strength of the molded body can be improved by manufacturing a slag-plastic composite by coating the slag with plastic, and manufacturing a molded body using this. In addition, in the case of manufacturing a molded article using several types of plastics with different physical properties, it was confirmed that a high-quality molded article having excellent mechanical properties could be manufactured by using a compatibilizer to uniformly mix the plastic melt. .

Although the present invention has been described with reference to the accompanying drawings and the above-described preferred embodiments, the present invention is not limited thereto, and is defined by the claims to be described later. Accordingly, those of ordinary skill in the art can variously change and modify the present invention within the scope without departing from the spirit of the claims to be described later.

100: coating unit 110: coating machine
120: cooler 300: molded part
312: extruder body 320: die
330: screw 340: second heating means
400: cut part

Claims (24)

the process of laying slag;
A process of preparing a plastic for coating and a plastic for filling comprising a plastic having a higher melting point than the plastic for coating;
attaching the plastic for coating to at least a portion of the slag to prepare a slag-plastic composite; and
The process of manufacturing a molded body by extruding a mixture including the slag-plastic composite and the plastic for filling; The method according to claim 1,
The process of preparing the slag includes a process of adjusting a component of adjusting the CaO content of the slag. The method according to claim 1,
The process of preparing the plastic for filling is,
The process of collecting two or more different types of waste plastics;
Classifying the waste plastic into a high melting point plastic having the highest melting point among the waste plastics and a low melting point plastic having a lower melting point than the high melting point plastic;
crushing each of the high-melting-point plastic and the low-melting-point plastic; and
The process of preparing the crushed high-melting-point plastic as the plastic for filling; a molding method comprising a. 4. The method according to claim 3,
The process of preparing the plastic for filling is,
A method for manufacturing a molded body comprising a step of mixing a portion of the crushed high-melting-point plastic and the crushed low-melting-point plastic. 4. The method according to claim 3,
A method for manufacturing a molded body comprising the step of preparing a compatibilizer for mixing the plastic for coating and the plastic for filling. 6. The method of claim 5,
The process of preparing the compatibilizer is,
A method for producing a molded article, comprising the step of preparing a compatibilizer including at least one of an epoxy functional group and a maleic anhydride functional group. 7. The method according to any one of claims 1 to 6,
The process of preparing the slag-plastic composite is,
heating the slag to have a temperature higher than or equal to the melting point of the plastic for coating;
The process of injecting the plastic for coating into the heated slag; and
A method of manufacturing a molded body comprising a; the process of attaching a plastic for coating to the surface of the heated slag. 8. The method of claim 7,
The process of injecting the plastic for coating into the heated slag,
A method of manufacturing a molded body comprising the step of adding 5 to 10% by weight of a plastic for coating based on the total of the heated slag and the plastic for coating. 8. The method of claim 7,
The process of producing the slag-plastic composite,
maintaining the temperature of the heated slag at a temperature greater than or equal to the melting point of the plastic for coating;
agitating the heated slag and the plastic for coating, bringing the plastic for coating into contact with the heated slag, and melting the plastic for coating by using the heat of the heated slag; and
The process of attaching a molten coating plastic to the surface of the heated slag; 8. The method of claim 7,
The process of manufacturing the molded body,
The slag-plastic composite and the total amount of the plastic for filling, 30 to 80% by weight of the slag-a molded body manufacturing method comprising the step of providing a plastic composite. 11. The method of claim 10,
The process of manufacturing the molded body,
A process of preparing a compatibilizer in an amount of 1 to 5% by weight with respect to the entire plastic for filling contained in the plastic for filling; and
Method for producing a molded body comprising a; step of extruding the mixture and the compatibilizer. 11. The method of claim 10,
The process of manufacturing the molded body includes a process of preparing an additive. 6. The method of claim 5,
The process of manufacturing the molded body,
A molding method comprising the step of extruding the mixture at a temperature equal to or higher than the melting point of the plastic for filling. 14. The method of claim 13,
The extrusion process is
and reacting the compatibilizer with at least one of the plastic for coating and the plastic for filling. 7. The method of claim 6,
The process of preparing the slag includes the process of preparing ferronickel slag generated in the process of manufacturing ferronickel molten steel,
The process of preparing the plastic for filling includes a process of preparing polyethylene terephthalate (PET) as the high-melting-point plastic. 16. The method of claim 15,
The process of manufacturing the molded body,
and reacting at least one of the epoxy functional group and the maleic anhydride functional group of the compatibilizer with at least one of the hydroxyl group (-OH) and the carboxyl group (-COOH) of the polyethylene terephthalate (PET). low melting point plastics;
High melting point plastic having a melting point higher than 50 ℃ than the low melting point plastic;
slag disposed to be dispersed in the form of particles in the low melting point plastic and the high melting point plastic; and
A molded body comprising a; compatibilizer combined with the high melting point plastic. 18. The method of claim 17,
The said slag is a molded object containing 10 weight% or less of CaO with respect to the said whole slag. 19. The method of claim 18,
The slag includes at least one of blast furnace slag, steelmaking slag and ferronickel slag,
The plastic is a molded body including waste plastic. 20. The method of claim 19,
The slag has a particle size of 0.01 to 0.15 mm. 20. The method of claim 19,
The slag is a molded body comprising angled polyhedral particles. 18. The method of claim 17,
The low-melting plastic includes at least one of polyethylene (PolyEthylene, PE), polypropylene (PolyPropylene, PP), polystyrene (PolyStyrene, PS) and polycarbonate (PolyCarbonate, PC),
The high-melting-point plastic is a molded article comprising polyethylene terephthalate (PET). 23. The method of claim 22,
The compatibilizer comprises at least one of an epoxy functional group and a maleic anhydride functional group. 24. The method of claim 23,
The compatibilizer is included in an amount of 1 to 5% by weight based on the entire high-melting point plastic molded article.

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