Waste treatment method, clinker production method, and waste treatment system

Abstract

To provide a waste treatment method, a clinker production method, and a waste treatment system capable of effectively selecting a chrome-containing object from a waste.SOLUTION: This waste treatment method for selecting a waste in order to use a plastic material contained in the waste as a heat energy source comprises: a first step of crushing the waste to generate a crushed object; a second step of executing magnetic force selection for the crushed object so as to set a magnetic flux density applied on the surface of the crushed object to 0.02-0.35 tesla and separating a first metal waste from the crushed object; and a third step of executing magnetic force selection for a residual so as to set a magnetic flux density applied on the surface of the residue after the separation of the first metal waste from the crushed object in the second step to 0.85-2 tesla and separating a second metal waste from the residue. A chrome content in the second metal waste is larger than that in the first metal waste.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a waste treatment method, a clinker production method, and a waste treatment system. [Background technology]

[0002] Metals are recovered from waste such as shredder residue, automobile shredder residue, and ordinary waste plastics (here, this refers to ordinary waste plastics other than SR and ASR, including, for example, construction waste plastics generated at construction sites and municipal waste), and the plastic materials are used as a thermal energy source in facilities such as factories, thereby reducing the environmental impact and making effective use of the waste. For example, Patent Document 1 discloses a treatment device for combustible waste. In this document, shredder residue may be referred to as "SR" (Shredder Residue). In this document, automobile shredder residue may be referred to as "ASR" (Automobile Shredder Residue). In this document, ordinary waste plastics refer to waste plastics other than SR and ASR (including, for example, construction waste plastics generated at construction sites and municipal waste), and ordinary waste plastics may be referred to as "ordinary waste plastics."

[0003] The processing device disclosed in Patent Document 1 includes a sieve separator for sieving SR, a first magnetic separator for magnetically separating undersized materials separated by the sieve separator, and a second magnetic separator for magnetically separating oversized materials separated by the sieve separator. The processing device also includes a third magnetic separator for magnetically separating again the non-magnetic materials separated by the first magnetic separator, and a fourth magnetic separator for magnetically separating again the non-magnetic materials separated by the second magnetic separator. The processing device also includes a first eddy current separator for eddy current separating the non-magnetic materials separated by the third magnetic separator, and a second eddy current separator for eddy current separating the non-magnetic materials separated by the fourth magnetic separator. The first and second eddy current separators are configured to remove non-magnetic metals, such as chromium derived from stainless steel, aluminum, copper, and brass, from the non-magnetic materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-000587 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure describes a waste treatment method, a clinker production method and a waste treatment system that are capable of effectively separating chromium-containing materials from waste. [Means for solving the problem]

[0006] One example of a waste treatment method is a method for sorting and treating waste to use plastic materials contained in the waste as a thermal energy source, the method comprising: a first step of crushing the waste to produce crushed material; a second step of magnetically separating the crushed material so that the magnetic flux density acting on the surface of the crushed material is 0.02 Tesla or more and 0.35 Tesla or less, thereby separating a first metal waste from the crushed material; and a third step of magnetically separating the residue obtained after the first metal waste has been separated from the crushed material in the second step so that the magnetic flux density acting on the surface of the residue is 0.85 Tesla or more and 2 Tesla or less, thereby separating a second metal waste from the residue. The chromium content in the second metal waste is greater than the chromium content in the first metal waste. [Effects of the Invention]

[0007] According to the waste treatment method, clinker production method, and waste treatment system disclosed herein, it is possible to effectively separate chromium-containing materials from waste. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram schematically illustrating an example of a clinker production facility. [Figure 2]FIG. 2 is a diagram for explaining a formula for calculating the magnetic flux density at a position away from a cylindrical magnet. [Figure 3] FIG. 3 is a partial cross-sectional view schematically showing an example of a vertical crusher. [Figure 4] FIG. 4 is a diagram schematically illustrating another example of a clinker production facility. [Figure 5] FIG. 5 is a diagram schematically illustrating another example of a clinker production facility. [Figure 6] FIG. 6 is a diagram showing a schematic example of a clinker manufacturing facility in which concerns are considered. [Figure 7] FIG. 7 is a table showing an example of the material composition and chromium content of SR and ASR. [Figure 8] FIG. 8 is a graph showing an example of the breakdown of chromium-containing substances in SR and ASR and their chromium contents. [Figure 9] FIG. 9 is a diagram showing an example of the proportion of chromium-containing substances in each sorting step. [Figure 10] FIG. 10 is a schematic diagram for explaining the details of the simulation experiment. [Figure 11] FIG. 11 is a table showing the results of simulating the first magnetic separation in simulation experiment 1. [Figure 12] Figure 12 is a graph showing the results of simulating the first magnetic separation in simulation experiment 1, where Figure 12(a) shows the iron recovery rate versus the magnetic flux density on the sample surface, Figure 12(b) shows the chromium recovery rate versus the magnetic flux density on the sample surface, and Figure 12(c) shows the plastic material contamination rate versus the magnetic flux density on the sample surface. [Figure 13] FIG. 13 is a table showing the results of simulating the second magnetic separation in simulation experiment 1. [Figure 14] Figure 14 is a graph showing the results of simulating the second magnetic separation in simulation experiment 1, where Figure 14(a) shows the iron recovery rate versus the magnetic flux density on the sample surface, Figure 14(b) shows the chromium recovery rate versus the magnetic flux density on the sample surface, and Figure 14(c) shows the plastic material contamination rate versus the magnetic flux density on the sample surface. [Figure 15]Figure 15 is a graph showing the results of the change in chromium content before and after magnetic separation using a bar magnet, simulating the second magnetic separation, for each magnetic flux density. Figure 15(a) shows the result when the magnetic flux density on the sample surface was 0.07 Tesla, Figure 15(b) shows the result when the magnetic flux density on the sample surface was 0.08 Tesla, and Figure 15(c) shows the result when the magnetic flux density on the sample surface was 0.15 Tesla. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the following description, the same elements or elements having the same functions will be designated by the same reference numerals, and redundant explanations will be omitted. Note that in this specification, when referring to the top, bottom, right, and left of a figure, the directions of the reference numerals in the figure will be used as the reference.

[0010] An example of a clinker production facility 1 will be described with reference to Figures 1 to 3. The clinker production facility 1 is part of a cement production facility, and is an apparatus for producing cement clinker W2 (clinker) from cement raw materials W1, as shown in Figure 1. The clinker production facility 1 includes a waste treatment system 10 and a kiln facility 2.

[0011] The waste treatment system 10 is configured to process waste W such as SR, ASR, and ordinary waste plastic, recover metals (iron M1 and magnetic stainless steel M2) from the waste W, and separate plastic materials P contained in the waste W. The waste treatment system 10 includes a receiving hopper 11, a vibration sorter 12, a crusher 13, a magnetic separator 14 (first magnetic separator), a magnetic separator 15 (second magnetic separator), a wind separator 16, a storage tank 17, a dryer 18, a thermal desalination furnace 19, and a vertical crusher 100.

[0012] The receiving hopper 11 is configured to temporarily store the waste W that has been transported to the clinker production facility 1. The waste W in the receiving hopper 11 is transported to the oscillating sorter 12 by a transport device (e.g., a feeder, a conveyor, etc.) not shown.

[0013] The oscillating sorter 12 is configured to separate the waste W transported from the receiving hopper 11 into light materials D1, heavy materials D2, and fine materials D3. The oscillating sorter 12 may be a so-called ballistic separator that uses characteristics such as differences in shape and specific gravity of the materials contained in the waste W to separate different types of materials by oscillating multiple inclined plates provided inside the main body. The oscillating sorter 12 may also use wind power to sort the waste W. The heavy materials D2 and fine materials D3 separated by the oscillating sorter 12 are each stored separately in storage units not shown. The light materials D1 separated by the oscillating sorter 12 are transported to the crusher 13 by a transport device (e.g., a conveyor) not shown.

[0014] The crusher 13 is configured to crush the lightweight materials D1. The crusher 13 may be, for example, a rotary hammer crusher. In this case, the crusher 13 may be a horizontal type (in which the rotation axis of the hammer extends horizontally) or a vertical type (in which the rotation axis of the hammer extends vertically). The crushed materials D4 crushed in the crusher 13 are transported to the magnetic separator 14 by a transport device (e.g., a conveyor) not shown.

[0015] The magnetic separator 14 is configured to separate the iron particles M1 (first metal waste) from the crushed materials D4 by magnetic force. The magnetic separator 14 may be a magnetic separator using, for example, a permanent magnet or an electromagnet. The magnetic separator 14 performs magnetic separation on the crushed materials D4 so that the magnetic flux density acting on the surface of the crushed materials D4 is 0.02 Tesla to 0.35 Tesla. The residue D5 remaining after the iron particles M1 have been separated from the crushed materials D4 in the magnetic separator 14 is transported to the magnetic separator 15 by a transport device (e.g., a conveyor) not shown.

[0016] The magnetic separator 15 is configured to separate the magnetic stainless steel M2 (second metal waste) from the residue D5 using magnetic force. That is, the chromium-containing material contained in the magnetic stainless steel M2 is magnetic. The magnetic separator 15 may be, for example, a magnetic separator using a permanent magnet or an electromagnet. The magnetic separator 15 performs magnetic separation on the residue D5 so that the magnetic flux density acting on the surface of the residue D5 is 0.85 to 2 tesla. The magnetic flux density acting on the surface of the residue D5 may be approximately 1.0 to 2 tesla, or approximately 1.2 to 1.7 tesla. The residue D6 remaining after the magnetic stainless steel M2 has been separated from the residue D5 in the magnetic separator 15 mainly contains plastic material P and is transported to the wind separator 16 by a transport device (e.g., a conveyor, etc.) not shown.

[0017] Here, for example, if the magnetic separators 14 and 15 use cylindrical magnets, the magnetic flux density on the central axis of the magnet and at a position away from the magnet can be calculated using Equation 1 (see also Figure 2).

number

[0018] Since the irons M1 are separated in the magnetic separator 14 and the magnetic stainless steel M2 is separated in the magnetic separator 15, the chromium content in the magnetic stainless steel M2 is greater than the chromium content in the irons M1. The chromium content in the waste W may be, for example, about 10 mg / kg to 14,000 mg / kg, about 100 mg / kg to 5,000 mg / kg, or about 500 mg / kg to 2,000 mg / kg. The chromium content in the irons M1 may be, for example, about 10 mg / kg to 20,000 mg / kg, about 500 mg / kg to 10,000 mg / kg, or about 1,000 mg / kg to 5,000 mg / kg. The chromium content in the magnetic stainless steel M2 may be, for example, approximately 400 mg / kg to 50,000 mg / kg, approximately 5,000 mg / kg to 30,000 mg / kg, or approximately 10,000 mg / kg to 20,000 mg / kg. That is, while the amount of chromium-containing materials mixed into the iron M1 is very small, the magnetic stainless steel M2 may contain most of the chromium-containing materials in the waste W. The recovery rate of chromium-containing materials by the magnetic separator 15 (the ratio of the chromium content in the magnetic stainless steel M2 to the chromium content in the waste W) may be, for example, approximately 3% or more, approximately 10% or more, approximately 40% or more, approximately 80% or more, or approximately 100%. The chromium content in the residue D6 may be, for example, 12,000 mg / kg or less, approximately 5,000 mg / kg or less, or approximately 300 mg / kg or less.

[0019] The air sorter 16 is configured to separate the residue D6 into light materials D7, foreign materials D8, and large lumps D9. Various types of air sorter 16 can be used, such as a blow-up type, a suction type, or a sealed type. The light materials D7 separated from the residue D6 by the air sorter 16 mainly contain plastic material P, similar to the residue D6.

[0020] The storage tank 17 is configured to temporarily store the light materials D7 separated from the residue D6 in the air sorter 16. The light materials D7 in the storage tank 17 are transported to the dryer 18 by a transport device (e.g., a feeder, a conveyor, etc.) not shown.

[0021] The dryer 18 is configured to evaporate the moisture contained in the light material D7 to dry the light material D7. The dryer 18 may completely evaporate the moisture contained in the light material D7, or may evaporate a sufficient amount of moisture to carbonize the light material D7 in the downstream thermal desalination furnace 19. The dryer 18 may employ various methods, such as a method of freeze-drying the object, a method of drying the object by blowing hot air onto the object, or a method of supplying the object into a processing chamber in a high-temperature atmosphere and drying it. The light material D7 dried by the dryer 18 is transported to the thermal desalination furnace 19 by a transport device (e.g., a conveyor) not shown.

[0022] The thermal desalination furnace 19 is configured to heat the light material D7 in a low-oxygen atmosphere to remove chlorine CL from the light material D7 and soften or embrittle the light material D7, thereby producing a desalination product D10. The desalination product D10 produced in the thermal desalination furnace 19 mainly contains plastic material P, similar to the residue D6 and the light material D7, and is transported to the vertical crusher 100 by a transport device (e.g., a conveyor, etc.) not shown. The desalination product D10 may be a carbonized product obtained by completely carbonizing the light material D7, or a semi-carbonized product obtained by partially carbonizing the light material D7 after the reaction has ended while leaving some carbonizable portions (organic matter) remaining.

[0023] The thermal desalination furnace 19 may heat the light material D7 at a temperature of, for example, about 250°C to 450°C for two hours or more. In this case, the plastic material P constituting the light material D7 tends to become sufficiently embrittled, and the desalted material D10 (plastic material P) tends to be able to be effectively crushed in the downstream vertical crusher 100. The heating temperature of the light material D7 in the thermal desalination furnace 19 may be, for example, about 310°C to 360°C.

[0024] Granular or powdered auxiliary materials C may be fed into the thermal desalination furnace 19 together with the lightweight materials D7. Examples of auxiliary materials include combustion improvers, chlorine fixation agents, grinding aids, and anti-fusing agents. Adding an anti-fusing agent to the thermal desalination furnace 19 can prevent melted plastics from fusing together and from adhering to the interior of the thermal desalination furnace 19. The anti-fusing agent may be, for example, pulverized coal or coal. Adding a chlorine fixation agent to the thermal desalination furnace 19 can fix chlorine CL generated from the chlorine-containing plastic material P.

[0025] The vertical crusher 100 is configured to crush the desalted material D10 into, for example, fine powder to produce crushed material D11. As illustrated in FIG. 3, the vertical crusher 100 includes power sources 110 and 120, a lower casing 130, an upper casing 140, a rotary table 150, a crushing section 160, and a separator 170.

[0026] The power source 110 includes a motor 111 and a reducer 112. The motor 111 is configured to rotate the rotary table 150 around a vertical axis via the reducer 112. The power source 120 includes a motor 121, a rotary cylinder 122, and a belt 123. The motor 121 is configured to rotate the rotary cylinder 122 around the vertical axis via the belt 123.

[0027] The rotating shell 122 extends vertically. The rotating shell 122 is rotatably attached to a top 142 (described later) of the upper casing 140 via a bearing 142b (described later). A supply pipe 124 extends along the interior of the rotating shell 122. The lower end of the supply pipe 124 is located above the center of the turntable 150. Therefore, the desalted material D10 supplied from the thermal desalination furnace 19 through the supply pipe 124 is discharged to the center of the turntable 150.

[0028] Belt 123 is stretched between a pulley attached to the rotating shaft of motor 121 and a pulley attached to the upper end of rotating barrel 122. In this way, the rotational force of motor 121 is transmitted to rotating barrel 122 by belt 123.

[0029] The lower casing 130 is installed on a foundation 130a such as the ground or an installation stand. The lower casing 130 includes a base portion 131 and a tubular portion 132. The base portion 131 is configured to accommodate, for example, the reducer 112, the lower portion of the grinding portion 160, the duct H1, the discharge pipe H2, and the like.

[0030] The duct H1 is a flow path for introducing heated gas from a gas supply unit (not shown) into the vertical crusher 100. The heated gas introduced from the duct H1 rises through the lower casing 130 and the upper casing 140, and then is discharged from a duct 143 (described later) of the upper casing 140.

[0031] The discharge pipe H2 is a flow path for discharging the desalted material D10 that has not been sufficiently pulverized in the pulverizing section 160 and has fallen from the rotary table 150 to the outside of the vertical crusher 100. The desalted material D10 discharged from the discharge pipe H2 may be discharged again onto the rotary table 150 via the supply pipe 124.

[0032] The cylindrical portion 132 is integrally connected to the upper end of the base portion 131 and has a cylindrical shape. The cylindrical portion 132 is configured to accommodate the rotary table 150, the upper portion of the crushing portion 160, the lower portion of the separator 170, etc.

[0033] The upper casing 140 includes a tubular portion 141, a top portion 142, and a duct 143. The tubular portion 141 is attached to the upper end of the tubular portion 132 and has a tubular shape. The tubular portion 141 is configured to accommodate the upper portion of the separator 170 and the like.

[0034] The top portion 142 is integrally connected to the upper end of the cylindrical portion 141, and closes the upper opening of the cylindrical portion 141. A bearing 142b is provided on the top wall of the top portion 142 so as to extend along the vertical direction.

[0035] Duct 143 extends outward from the side wall or upper portion of top 142 and is cylindrical. Duct 143 is connected to burner 2b of kiln body 2a and / or a burner of the calciner (described later). Duct 143 is a flow path for sending pulverized material D11, which is obtained by pulverizing desalted material D10 in vertical pulverizer 100, and heating gas supplied from the gas supply unit into vertical pulverizer 100, to burner 2b of kiln body 2a and / or a burner of the calciner.

[0036] The rotary table 150 is configured to receive the desalted material D10 discharged from the lower end of the supply pipe 124 and to transfer the desalted material D10 to the outer periphery by centrifugal force generated by the rotation of the rotary table 150.

[0037] The crushing unit 160 is disposed near the outer periphery of the turntable 150. The vertical crusher 100 may include a plurality of crushing units 160. In this case, the plurality of crushing units 160 may be disposed at the outer periphery of the turntable 150 at approximately equal intervals along the outer periphery of the turntable 150.

[0038] The crushing unit 160 includes a crushing roller 161, a holding unit 162, an arm 163, and a hydraulic cylinder 164. The crushing roller 161 is rotatably attached to the holding unit 162. The crushing roller 161 may have, for example, a truncated cone shape. The crushing roller 161 is disposed so that its peripheral surface faces the outer periphery of the turntable 150. The crushing roller 161 rotates in response to the rotation of the turntable 150.

[0039] The crushing roller 161 is configured to apply pressure to the desalted material D10 that has entered the gap between the peripheral surface of the crushing roller 161 and the outer periphery of the rotary table 150, thereby crushing the desalted material D10. The crushed desalted material D10 is dried while being blown up by the heated gas introduced from the duct H1, and after rising through the lower casing 130 and the upper casing 140 accompanied by the heated gas, is introduced into the separator 170. The heated gas accompanying the crushed desalted material D10 is sometimes referred to as a "solid-gas two-phase flow."

[0040] The holder 162 is configured to rotate the crushing roller 161 around an axis that extends horizontally along the tangential direction of the rotary table 150. The arm 163 connects the holder 162 and the hydraulic cylinder 164.

[0041] The hydraulic cylinder 164 is configured to extend and retract a piston rod. An arm 163 is connected to the tip of the piston rod. Therefore, when the hydraulic cylinder 164 extends and retracts the piston rod, the crushing roller 161 swings toward or away from the upper surface of the turntable 150 via the holding portion 162 and the arm 163. This changes the distance between the peripheral surface of the crushing roller 161 and the outer periphery of the turntable 150, changing the pressure applied to the desalted material D10 and adjusting the particle size of the crushed material D11.

[0042] The separator 170 includes a rotating rotor 171, a plurality of fixed blades 172, and a cone 173. The rotating rotor 171 is attached to the rotating barrel 122 and is configured to rotate together with the rotating barrel 122. The rotating rotor 171 includes a plurality of blade members 171a extending in the vertical direction. When viewed from above, the plurality of blade members 171a are arranged in a circular shape at approximately equal intervals around the rotation axis of the rotating rotor 171 (rotating barrel 122). Therefore, slit openings OP1 extending in the vertical direction are formed between the plurality of blade members 171a.

[0043] The pulverized material D11 produced by pulverizing the desalted material D10 using the pulverizing roller 161 is classified into a predetermined particle size according to the rotation speed of the rotor 171, based on the balance between the centrifugal force of the swirling flow generated around the rotor 171 as the rotor rotates and the airflow attempting to pass through the slit opening OP1. Relatively fine particles of the pulverized material D11 that pass through the slit opening OP1 and enter the interior of the rotor 171 are discharged from the duct 143 accompanied by the heated gas and sent to the burner 2b of the kiln body 2a and / or the burner of the calciner. On the other hand, relatively coarse particles of the pulverized material D11 that cannot pass through the slit opening OP1 are repelled outward by the centrifugal force.

[0044] The plurality of fixed vanes 172 are arranged on the outer periphery of the rotating rotor 171. The plurality of fixed vanes 172 are fixed near the boundary between the tubular portion 141 and the top portion 142 of the upper casing 140 via, for example, an annular (ring-shaped) plate member 174. The plate member 174 is configured to prevent the gas-solid two-phase flow from flowing from the tubular portion 141 to the top portion 142 without passing through the separator 170 (so-called short-path flow).

[0045] When viewed from above, the multiple fixed vanes 172 are arranged in a circle at approximately equal intervals around the rotation axis of the rotating rotor 171 (rotating cylinder 122) while being inclined at a predetermined angle with respect to an imaginary line in the radial direction. Therefore, slit openings OP2 extending in the vertical direction are formed between the multiple fixed vanes 172. The multiple fixed vanes 172 impart a swirl to the gas-solid two-phase flow when the solid-gas two-phase flow passes through the slit openings OP2, thereby forming a swirling flow of the gas-solid two-phase flow.

[0046] The cone 173 has a funnel shape that narrows downward. The upper end of the cone 173 is connected to the lower ends of the multiple fixed blades 172. The cone 173 is positioned so as to surround the lower part of the supply pipe 124 from the outside. Therefore, the relatively coarse particles of the pulverized material D11 that are bounced off the rotating rotor 171 fall through the space between the inner peripheral surface of the cone 173 and the outer peripheral surface of the lower part of the supply pipe 124, and are discharged from the opening at the lower end of the cone 173 to the center of the turntable 150. As a result, the relatively coarse particles of the pulverized material D11 are again subjected to pulverization by the pulverizing roller 161.

[0047] Returning to FIG. 1 , the kiln equipment 2 includes a kiln body 2a and a burner 2b provided in front of the kiln body 2a. The kiln equipment 2 is configured to burn pulverized material D11 supplied to the burner 2b, thereby burning the cement raw material W1 fed from the kiln bottom of the kiln body 2a and producing cement clinker W2. In other words, the pulverized material D11 is used as a thermal energy source for burning the cement raw material W1. In addition, the pulverized material D11 fed into the kiln body 2a via the burner 2b is also used as part of the cement raw material W1. The kiln body 2a may be, for example, a rotary kiln extending horizontally.

[0048] The kiln equipment 2 may further include a suspension preheater (not shown) provided at the end of the kiln body 2a. The suspension preheater is configured to preheat the cement raw materials W1 using heat generated in the kiln body 2a. The kiln equipment 2 may further include a calciner (not shown) disposed between the end of the kiln body 2a and the suspension preheater. The calciner is configured to calcinate the cement raw materials W1 preheated by the suspension preheater. The pulverized material D11 generated in the vertical pulverizer 100 may be supplied to a burner (not shown) of the calciner. That is, the pulverized material D11 may be used as a thermal energy source for calcining the cement raw materials W1.

[0049] [Effect] According to the above example, after the iron M1 with a relatively low chromium content is separated from the crushed material D4 by the magnetic separator 14 (first magnetic separation), the magnetic stainless steel M2 with a relatively high chromium content is separated from the residue D5 by the magnetic separator 15 (second magnetic separation). That is, the chromium-containing materials are concentrated in the magnetic stainless steel M2 recovered by the magnetic separator 15. Therefore, the chromium-containing materials can be effectively separated by the magnetic separator 15.

[0050] According to the above example, iron M1 and magnetic stainless steel M2 are recovered in the magnetic separators 14 and 15. Therefore, the residue D6 remaining after the magnetic stainless steel M2 is separated from the residue D5 in the magnetic separator 15 is mainly composed of plastic material P. Therefore, the plastic material P can be effectively separated from multiple metal wastes with different chromium contents, and each can be efficiently and effectively utilized.

[0051] According to the above example, iron M1 and magnetic stainless steel M2 are recovered in the magnetic separators 14, 15 before the heat treatment in the thermal desalination furnace 19. Therefore, the plastic material P and the metal waste are separated before the plastic material melts and fuses to the metals in the thermal desalination furnace 19. Therefore, the plastic material P can be recovered more effectively.

[0052] According to the above example, metal waste (iron M1 and magnetic stainless steel M2) is separated in stages, so the separation process is completed on the same line. In other words, no separate separation process is required for the iron M1 recovered by the magnetic separator 14 and the magnetic stainless steel M2 recovered by the magnetic separator 15. This makes it possible to simplify the waste treatment system 10 for separating the waste W. This effect is particularly noticeable when separating SR and ASR, which are prone to entanglement with metals and plastic materials and can be time-consuming to separate.

[0053] According to the above example, before the pulverization process in the vertical pulverizer 100, the iron M1 and the magnetic stainless steel M2 are recovered by the magnetic separators 14 and 15 (two magnetic separations). This makes it difficult for the metals to reach subsequent structures (for example, the interior of the vertical pulverizer 100, the injection line from the vertical pulverizer 100 to the burner 2b of the kiln body 2a, the injection line from the vertical pulverizer 100 to the burner of the calciner, etc.). This makes it possible to suppress wear and damage to subsequent structures.

[0054] [Variations] The disclosure in this specification should be considered to be illustrative in all respects and not restrictive. Various omissions, substitutions, modifications, etc. may be made to the above examples without departing from the scope and spirit of the claims.

[0055] (1) As illustrated in FIG. 4, the magnetic separator 15 may be disposed between the thermal desalination furnace 19 and the vertical crusher 100. That is, the magnetic separator 15 may perform magnetic separation on the desalted material D10 to separate the magnetic stainless steel M2 from the desalted material D10. In this case, the magnetic separator 15 performs magnetic separation on the desalted material D10 so that the magnetic flux density acting on the surface of the desalted material D10 is 0.06 Tesla or higher. The magnetic flux density acting on the surface of the desalted material D10 may be approximately 0.03 Tesla to 0.2 Tesla, or approximately 0.05 Tesla to 0.1 Tesla. The residue D6 remaining after the magnetic stainless steel M2 has been separated from the desalted material D10 by the magnetic separator 15 mainly contains plastic material P and is transported to the vertical crusher 100 by a transport device (e.g., a conveyor, etc.) not shown.

[0056] 4, the residue D5 remaining after the iron M1 has been separated from the crushed material D4 in the magnetic separator 14 is transported by a transport device (e.g., a conveyor) (not shown) to the air separator 16. The air separator 16 separates the residue D5 into light materials D7, foreign materials D8, and large lumps D9.

[0057] 4, after the iron M1 with a relatively low chromium content is separated from the crushed material D4 by the magnetic separator 14 (first magnetic separation), the magnetic stainless steel M2 with a relatively high chromium content is separated from the residue D5 by the magnetic separator 15 (second magnetic separation). That is, the chromium-containing materials are concentrated in the magnetic stainless steel M2 recovered by the magnetic separator 15. This allows the magnetic separator 15 to effectively separate the chromium-containing materials.

[0058] According to the embodiment illustrated in Fig. 4, metal waste (iron M1 and magnetic stainless steel M2) is separated in stages, so the separation process is completed on the same line. In other words, no separate separation process is required for the iron M1 recovered by the magnetic separator 14 and the magnetic stainless steel M2 recovered by the magnetic separator 15. This makes it possible to simplify the waste treatment system 10 for separating the waste W. This effect is particularly noticeable when separating SR and ASR, which are prone to entanglement with metals and plastic materials and can be time-consuming to separate.

[0059] 4, iron M1 and magnetic stainless steel M2 are recovered in magnetic separators 14 and 15. Therefore, the residue D6 remaining after magnetic stainless steel M2 is separated from residue D5 in magnetic separator 15 is mainly composed of plastic material P. Therefore, plastic material P can be effectively separated from multiple metal wastes with different chromium contents, and each can be efficiently and effectively utilized.

[0060] 4, the light material D7 is heated to produce a brittle desalted material D10, which is then subjected to a second magnetic separation using a magnetic separator 15. This makes it easier to separate the magnetic stainless steel M2 from the brittle desalted material D10 during the second magnetic separation. This allows for a higher recovery rate of chromium-containing materials from the waste W.

[0061] (2) As illustrated in FIG. 5, the magnetic separator 15 may be disposed between the vertical crusher 100 and the kiln equipment 2. That is, the magnetic separator 15 may perform magnetic separation on the crushed material D11 (the demineralized material D10 pulverized into fine particles by crushing) to separate the magnetic stainless steel M2 from the crushed material D11. In this case, similar to the example of FIG. 4, the magnetic separator 15 performs magnetic separation on the crushed material D11 so that the magnetic flux density acting on the surface of the crushed material D11 is 0.06 Tesla or more. The magnetic flux density acting on the surface of the crushed material D11 may be approximately 0.03 Tesla to 0.2 Tesla, or approximately 0.05 Tesla to 0.1 Tesla. The residue D6 remaining after the magnetic stainless steel M2 has been separated from the demineralized material D10 by the magnetic separator 15 mainly contains plastic material P and is transported to the burner 2b of the kiln equipment 2 via piping or the like, for example, by wind power.

[0062] 5, the residue D5 remaining after the iron M1 has been separated from the crushed material D4 in the magnetic separator 14 is transported by a transport device (e.g., a conveyor) (not shown) to the air separator 16. The air separator 16 separates the residue D5 into light materials D7, foreign materials D8, and large lumps D9.

[0063] The embodiment illustrated in Fig. 5 provides the same effects as the embodiment illustrated in Fig. 4. In addition, the embodiment illustrated in Fig. 5 performs a second magnetic separation on the pulverized material D11 (the demineralized material D10 pulverized into fine particles by pulverization) using a magnetic separator 15. This makes it easier to separate the magnetic stainless steel M2 from the pulverized material D11 during the second magnetic separation. This makes it possible to further increase the recovery rate of chromium-containing materials from the waste W.

[0064] (3) The waste treatment system 10 may employ various sorting methods to sort the waste W. Examples of the various sorting methods include a method that uses magnetic force (magnetic sorter), a method that uses eddy currents (eddy current sorter), a method that uses sieves (sieve sorter), a method that uses specific gravity differences (wind sorter, shaking sorter), and a method that uses shape differences (shaking sorter). The order in which these sorting methods are applied to the waste W may be changed as appropriate depending on the purpose of the sorting, as long as sorting by the magnetic sorter 14 is performed before sorting by the magnetic sorter 15. The number of times these sorting methods are applied to the waste W may be one or multiple times depending on the purpose of the sorting.

[0065] The air sorter 16 may be arranged, for example, upstream of the magnetic separators 14, 15, between the magnetic separators 14, 15, or downstream of the magnetic separators 14, 15. The waste treatment system 10 may be equipped with, for example, a plurality of air sorters 16. In this case, one of the plurality of air sorters 16 may be arranged upstream of the magnetic separators 14, 15, and another of the plurality of air sorters 16 may be arranged downstream of the magnetic separators 14, 15.

[0066] [Concerns] As mentioned above, in order to achieve carbon neutrality, efforts are being made to recover metals from waste W, such as SR, ASR, construction waste plastics, and municipal waste, and use the resulting plastic material P as a thermal energy source in factories and other facilities. For example, when plastic material P sorted from waste W is used in a cement factory (clinker production facility 1), the plastic material P is fed into kiln facility 2 and used as part of the cement raw material W1, as well as a thermal energy source for burning the cement raw material W1. However, waste W contains various foreign matter. In particular, SR and ASR contain large amounts of metals (e.g., iron M1, stainless steel, etc.). Therefore, if foreign matter and metals are not sufficiently recovered from waste W through sorting processing, the following concerns arise.

[0067] (Concern 1) Chromium-containing materials in the waste W may be brought into the clinker manufacturing facility 1, increasing the chromium content in the cement. This may affect the quality of the cement.

[0068] (Concern 2) According to the "Guidelines for Water-Soluble Hexavalent Chromium Content in Cement" established by the Japan Cement Association, the chromium content in cement must not exceed the specified control standard. Therefore, there is a concern that the amount of SR and ASR that can be used may be restricted when separating plastic material P from SR and ASR and using it as a thermal energy source.

[0069] (Concern 3) If metals are not sufficiently recovered from the waste W, there is a concern that the metals may come into contact with or collide with subsequent structures (e.g., devices, equipment, etc.), causing wear and damage to the subsequent structures and requiring frequent repairs. For example, in the case of the clinker production facility 1, wear and damage are likely to occur inside the vertical pulverizer 100 (e.g., the rotary table 150, the pulverizer roller 161, the blade member 171a, the fixed blade 172, etc.), the injection line from the vertical pulverizer 100 to the burner 2b of the kiln facility 2, the injection line from the vertical pulverizer 100 to the burner of the calciner, etc.

[0070] (Concern 4) Chromium-containing materials can take various forms, such as non-magnetic materials like chrome plating, or non-magnetic or weakly magnetic materials like stainless steel. Therefore, completely eliminating chromium-containing materials typically requires the use of multiple sorting machines, such as magnetic separators, eddy current separators, and electromagnetic induction separators, in multiple stages. Furthermore, magnetic separators require a strong magnetic flux density. This increases the complexity and size of the sorting equipment, raising concerns about increased operating costs.

[0071] (Concern 5) Of the metals recovered from waste W, iron M1 can be sold as a valuable resource. Therefore, it is conceivable to separate the metals contained in waste W into iron M1 and other metals. However, if the magnetic flux density of the magnetic separation for recovering iron M1 is too small, there is a concern that the recovery rate of iron M1 will decrease. On the other hand, if the magnetic flux density of the magnetic separation for recovering iron M1 is too large, there is a concern that not only iron M1 but also metals other than iron M1 and plastic material P bonded to the metals will be recovered.

[0072] The present inventors have conducted extensive research into the above concerns and have discovered factors that may lead to insufficient recovery of chromium-containing materials from the waste W. The research conducted by the present inventors will be described below with reference to FIGS. 6 to 9. The research described below was carried out using a clinker production plant 1A illustrated in FIG. 6. The clinker production plant 1A has the same configuration as the clinker production plant 1 illustrated in FIG. 1, except that it does not include a magnetic separator 15.

[0073] (Study 1) Identification of chromium-containing materials brought into the waste treatment system 10 First, using SR and ASR as waste W, a quantitative analysis of the chromium content was carried out on the pulverized material D11 fed into the kiln facility 2. As a result, it was found that the pulverized material D11 contained approximately 100 mg / kg to 1660 mg / kg of chromium.

[0074] Next, the origin of chromium was investigated using SR and ASR as waste W. Specifically, SR (1 sample) and ASR (2 samples) in the light material D7 before treatment in the thermal desalination furnace 19 were sieved (mesh opening: 5 mm). Next, the over-sieved fraction (residue that did not pass through the sieve) was manually separated into the following categories: 1) Metal (stainless steel) 2) Metal (aluminum) 3) Wire 4)Electric wire 5) Hard plastic 6) Soft plastic, rubber pieces, paper 7) Sponge 8) Cloth-like material 9) Hard plastic + plating 10) Dust 11) Other (glass fragments, etc.)

[0075] Next, the chromium content (ratio of chromium content to the weight of the separated material) of each separated material was measured using a handheld XRF (X-ray fluorescence analyzer). The measurement results are shown in Figure 7. Figure 7 shows that chromium was found to be contained in 1) metal (stainless steel), 3) wire, and 9) hard plastic + plating. It was found that chromium was particularly concentrated in 1) metal (stainless steel).

[0076] (Study 2) Identification of chromium-containing substances that contribute significantly to the introduction of chromium into the waste treatment system 10 Using 1) metal (stainless steel) and 2) hard plastic with plating in Study 1, we investigated chromium-containing materials that contribute significantly to the introduction of chromium into the waste treatment system 10. Specifically, SR and ASR samples were collected eight times from lightweight material D7 after drying in a dryer 18 and before treatment in a thermal desalination furnace 19, yielding samples a to h. The chromium-containing material from which the chromium originated was identified for each sample a to h, and its chromium content was measured using a handheld XRF (X-ray fluorescence analyzer). The results are shown in Figure 8. Figure 8 indicates that most of the chromium in lightweight material D7 originated from stainless steel, with magnetic stainless steel contributing significantly. The metal content of lightweight material D7 after drying was 0.43% to 1.60% by mass.

[0077] (Study 3) Identifying the proportion of chromium-containing substances in each sorting process The proportion of chromium-containing materials in each sorting process was investigated. Specifically, using SR and ASR as waste W, the waste W in the receiving hopper 11, the magnetically separated materials after magnetic separation by the magnetic separator 14, the heavy materials after air separation by the air separator 16, the light materials D7 after drying by the dryer 18, and the mill waste stone discharged from the vertical crusher 100 were each separated into magnetic stainless steel, non-magnetic stainless steel, and chrome plating, and the proportion of each chromium-containing material was calculated. The results are shown in Figure 9. The magnetic flux density on the surface of the materials to be sorted by the magnetic separator 14 was 0.094 Tesla.

[0078] According to Figure 9, the waste W in the receiving hopper 11 contained 93% magnetic stainless steel, 6% non-magnetic stainless steel, and 1% chrome-plated material. The magnetically separated material after magnetic separation by the magnetic separator 14 contained 100% magnetic stainless steel, 0% non-magnetic stainless steel, and 0% chrome-plated material. The light material D7 after drying by the dryer 18 contained 71% magnetic stainless steel, 28% non-magnetic stainless steel, and 1% chrome-plated material. The mill waste discharged from the vertical crusher 100 contained 81% magnetic stainless steel, 19% non-magnetic stainless steel, and 0% chrome-plated material. From the above, it was confirmed that there was magnetic stainless steel that had not been recovered by the magnetic separator 14.

[0079] Furthermore, when the proportion of magnetic stainless steel in the lightweight material D7 after drying in the dryer 18 was compared with the proportion of magnetic stainless steel in the mill waste stone discharged from the vertical crusher 100, it was confirmed that the proportion of magnetic stainless steel had increased in the latter. The detailed mechanism behind this is not entirely clear, but it is thought that the heating in the thermal desalination furnace 19 and / or the pressurization in the vertical crusher 100 may have transformed some of the non-magnetic austenitic stainless steel into magnetic stainless steel (ferritic, martensitic).

[0080] (Summary of the review) As a result of the above studies 1 to 3 by the present inventors, the present inventors have found the following for the first time. -Chromium is mainly derived from metal (stainless steel). -Magnetic stainless steel contributes significantly. - There is magnetic stainless steel that has not been recovered in the magnetic separator 14. There is a possibility that non-magnetic stainless steel may have been transformed into magnetic stainless steel through processing in the thermal desalination furnace 19 and the vertical crusher 100.

[0081] The inventors then discovered that by magnetically separating waste material W using two magnetic separators 14, 15, as in the clinker production facility 1 illustrated in Figures 1, 4, and 5, and by setting the magnetic flux density acting on the surfaces of the objects to be separated in the magnetic separators 14, 15 within a predetermined range, sufficient amounts of irons M1 and magnetic stainless steel M2 can be recovered individually, leading to the completion of the present invention. Therefore, below, simulation experiments 1 and 2 conducted to determine the range of magnetic flux density will be described.

[0082] (Simulation experiment 1) Simulation experiment 1 is a simulation experiment to determine the range of magnetic flux density in the first form (clinker production equipment 1 illustrated in Figure 1) in which two magnetic separations are performed before treatment in the thermal desalination furnace 19.

[0083] First, SR, ASR, and regular waste plastic were used as waste W. Regarding the SR, as a pretreatment, the SR was crushed using a crusher 13 to prepare a sample (hereinafter, sometimes referred to as the "SR sample"). The chromium content of the SR sample was 10,953 mg / kg. Regarding the ASR, as a pretreatment, light materials were separated from the ASR using a vibration separator 12, and then the light materials were crushed using a crusher 13 to prepare a sample (hereinafter, sometimes referred to as the "ASR sample"). The chromium content of the ASR sample was 10,894 mg / kg. Regarding the regular waste plastic, as a pretreatment, the regular waste plastic was crushed using a crusher 13 to prepare a sample (hereinafter, sometimes referred to as the "regular waste plastic sample"). The chromium content of the regular waste plastic sample was 10,894 mg / kg. To facilitate understanding of the difference in metal recovery amount due to changes in magnetic flux density, separately prepared stainless steel pieces were added to each sample and mixed.

[0084] Next, the following procedure was carried out for each sample. 1) The sample S1 was placed in a vat WB (a shallow box-shaped container) and spread out completely. A bar magnet BM was then moved back and forth directly above the vat WB (see arrow Ar in Figure 10(a)). Each sample S1 was placed in the vat WB with approximately the same weight. Since the distance between the bar magnet BM and the surface of the sample S1 was nearly zero, the magnetic flux density at the surface of the sample S1 due to the bar magnet BM was approximately equal to the magnetic flux density at the surface of the bar magnet BM. For sample No. 1 in Figure 11, a bar magnet BM with a surface magnetic flux density of 0.02 Tesla was not available. Therefore, a bar magnet BM with a surface magnetic flux density of 0.12 Tesla was used. The bar magnet BM was moved back and forth above the vat WB while being spaced from the surface of the sample S1 so that the magnetic flux density at the surface of the sample S1 due to the bar magnet BM was 0.02 Tesla.

[0085] 2) The deposit S2 attached to the bar magnet BM was collected (see FIG. 10(b)). 3) The presence or absence of stainless steel was determined for the metals in the collected deposits S2 using a handheld XRF. 4) The above operations 1) to 3) were repeated while changing the bar magnet BM to one with a different magnetic flux density (see the magnetic flux density columns in FIGS. 11 and 13).

[0086] 11 and 12 show the results of simulating the first magnetic separation. FIGS. 13 and 14 show the results of simulating the second magnetic separation. To simulate the second magnetic separation, the SR sample of sample No. 5 in FIG. 11 after magnetic separation (sample S1 after the attachment S2 was removed) was used as samples Nos. 23 to 27 in FIG. 13. Similarly, the ASR sample of sample No. 12 in FIG. 11 after magnetic separation (sample S1 after the attachment S2 was removed) was used as samples Nos. 28 and 29 in FIG. 13. Similarly, the normal waste plastic sample of sample No. 19 in FIG. 11 after magnetic separation (sample S1 after the attachment S2 was removed) was used as samples Nos. 30 to 34 in FIG. 13.

[0087] 11 and 12 , it was confirmed that in the first magnetic separation, when the magnetic flux density acting on the sample surface was 0.02 to 0.35 Tesla, iron M1 could be recovered with extremely high efficiency while suppressing the inclusion of magnetic stainless steel M2. As shown in FIGS. 13 and 14 , it was confirmed that in the second magnetic separation, when the magnetic flux density acting on the sample surface was 0.85 to 2 Tesla, magnetic stainless steel M2 could be recovered with extremely high efficiency while suppressing the inclusion of plastic materials. In particular, when the samples were SR and ASR, it was confirmed that when the magnetic flux density was 0.85 to 2 Tesla, magnetic stainless steel M2 could be recovered with extremely high efficiency while suppressing the inclusion of plastic materials. Note that in FIGS. 11 and 12 , the iron recovery rate of the normal waste plastic samples (samples No. 16 to 22) was lower than that of the other samples, and in FIGS. 13 and 14 , the chromium recovery rate of the normal waste plastic samples (samples No. 30 to 34) was lower than that of the other samples. This is presumably because, in the process of spreading each sample of uniform weight onto the vat WB (see 1) above), a relatively large amount of the ordinary waste plastic sample, which has a lower bulk density than the other samples, is placed into the vat WB, and the iron M1 and magnetic stainless steel M2 at the bottom of the vat WB are not attracted to the bar magnet BM. In the actual clinker production facility 1, the materials to be sorted are transported by a transport device when being sorted by the magnetic separators 14 and 15, making such concerns unlikely to arise, and it is presumed that the iron M1 and magnetic stainless steel M2 are sufficiently recovered even from ordinary waste plastic.

[0088] (Simulation experiment 2) Simulation experiment 2 is a simulation experiment to determine the range of magnetic flux density in a second form (clinker production equipment 1 illustrated in Figures 4 and 5) in which a second magnetic separation is performed after treatment in a thermal desalination furnace 19.

[0089] First, a pulverized material D11 obtained by treating waste W in the clinker production facility 1 illustrated in Figures 4 and 5 was collected and designated as sample S1. The chromium content of the pulverized material D11 was 2527.0 mg / kg. That is, sample S1 was subjected to a first magnetic separation using the magnetic separator 14. In the first magnetic separation, the magnetic flux density acting on the surface of the sample was 0.094 Tesla.

[0090] Next, the following procedure was carried out on sample S1. 1) The sample S1 was placed in a vat WB (a shallow box-shaped container) and spread out completely, and a bar magnet BM was moved back and forth directly above the vat WB (see arrow Ar in Figure 10(a)). At this time, the distance between the bar magnet BM and the surface of the sample S1 was almost zero, so the magnetic flux density on the surface of the sample S1 due to the bar magnet BM was approximately equal to the magnetic flux density on the surface of the bar magnet BM. In simulation experiment 2, this magnetic separation by the bar magnet BM corresponds to the second magnetic separation.

[0091] 2) The deposit S2 attached to the bar magnet BM was collected (see FIG. 10(b)). 3) The presence or absence of stainless steel was determined for the metals in the collected deposits S2 using a handheld XRF. 4) The above steps 1) to 3) were repeated while changing the bar magnet BM to one with a different magnetic flux density. Specifically, bar magnets BM with surface magnetic flux densities of 0.07 Tesla, 0.08 Tesla, and 0.15 Tesla were used.

[0092] Figure 15 shows the change in chromium content before and after magnetic separation using a bar magnet BM, simulating the second magnetic separation, for each magnetic flux density. It was confirmed that chromium could be recovered with high efficiency when the magnetic flux density acting on the surface of sample S1 was 0.07 Tesla, 0.08 Tesla, or 0.15 Tesla. In other words, it was confirmed that a sufficient recovery rate of magnetic stainless steel M2 could be achieved when the magnetic flux density acting on the surface of sample S1 was 0.06 Tesla or higher.

[0093] [Other examples] Example 1. One example of a waste treatment method is a method for sorting and treating waste to use plastic materials contained in the waste as a thermal energy source, the method comprising: a first step of crushing the waste to produce crushed material; a second step of magnetically separating the crushed material so that the magnetic flux density acting on the surface of the crushed material is 0.02 Tesla or more and 0.35 Tesla or less, thereby separating a first metal waste from the crushed material; and a third step of magnetically separating the residue obtained after the first metal waste has been separated from the crushed material in the second step so that the magnetic flux density acting on the surface of the residue is 0.85 Tesla or more and 2 Tesla or less, thereby separating a second metal waste from the residue. The chromium content in the second metal waste is greater than the chromium content in the first metal waste.

[0094] According to Example 1, after the first magnetic separation separates the first metal waste, which has a relatively low chromium content, from the crushed material, the second magnetic separation separates the second metal waste, which has a relatively high chromium content, from the residue. That is, chromium-containing materials are concentrated in the second metal waste recovered in the second magnetic separation. Therefore, chromium-containing materials can be effectively separated in the second magnetic separation.

[0095] According to Example 1, metal waste is separated in stages, and the separation process is completed on the same line. In other words, separate separation processes are not required for the first metal waste recovered by the first magnetic separation and the second metal waste recovered by the second magnetic separation. This makes it possible to simplify the equipment for separating waste. This effect is particularly noticeable when separating SR and ASR, which are prone to entanglement between metals and plastic materials and can be time-consuming to separate.

[0096] According to Example 1, the first and second metal wastes are collected by two magnetic separations. This makes it difficult for metals to reach subsequent structures. This makes it possible to suppress wear and damage to subsequent structures.

[0097] Example 2. Another example of a waste treatment method is a method for sorting and treating waste to use plastic materials contained in the waste as a thermal energy source, the method comprising: a first step of crushing the waste to produce crushed material; a second step of performing magnetic separation on the crushed material so that the magnetic flux density acting on the surface of the crushed material is 0.02 Tesla or more and 0.35 Tesla or less to separate a first metal waste from the crushed material; a third step of heating the residue remaining after the first metal waste has been separated from the crushed material in the second step at 250°C or more and 450°C or less to produce a demineralized material; and a fourth step of performing magnetic separation on the demineralized material so that the magnetic flux density acting on the surface of the demineralized material is 0.06 Tesla or more to separate a second metal waste from the demineralized material. The chromium content in the second metal waste is greater than the chromium content in the first metal waste.

[0098] According to Example 2, after the first magnetic separation separates the first metal waste, which has a relatively low chromium content, from the crushed material, the second magnetic separation separates the second metal waste, which has a relatively high chromium content, from the residue. That is, chromium-containing materials are concentrated in the second metal waste recovered in the second magnetic separation. Therefore, chromium-containing materials can be effectively separated in the second magnetic separation.

[0099] According to Example 2, metal waste is separated in stages, and the separation process is completed on the same line. In other words, separate separation processes are not required for the first metal waste recovered by the first magnetic separation and the second metal waste recovered by the second magnetic separation. This makes it possible to simplify the equipment for separating waste. This effect is particularly noticeable when separating SR and ASR, which are prone to entanglement between metals and plastic materials and can be time-consuming to separate.

[0100] According to Example 2, the demineralized material is heated and made brittle, and then subjected to a second magnetic separation. This makes it easier to separate the second metal waste from the brittle demineralized material during the second magnetic separation. This makes it possible to further increase the recovery rate of chromium-containing materials from the waste.

[0101] Example 3: The method of Example 2 may further include a fifth step of pulverizing the demineralized material produced in the third step, and a fourth step of magnetically separating the demineralized material after pulverization in the fifth step to separate the second metal waste from the demineralized material. In this case, the second magnetic separation is performed on the demineralized material that has been pulverized. Therefore, during the second magnetic separation, the second metal waste is more easily separated from the pulverized demineralized material. This makes it possible to further increase the recovery rate of chromium-containing materials from the waste.

[0102] Example 4 In any of the methods of Examples 1 to 3, the chromium content in the waste may be 10 mg / kg or more and 14,000 mg / kg or less.

[0103] Example 5 In the method of any one of Examples 1 to 4, the chromium content in the residue after the second metal waste is separated may be 12000 mg / kg or less.

[0104] Example 6 In the method of any one of Examples 1 to 5, the waste may contain chromium-containing materials that are magnetic.

[0105] Example 7 In the method of any one of Examples 1 to 6, the waste may contain at least one selected from the group consisting of shredder dust, automobile shredder dust, and waste plastics.

[0106] Example 8: Any of the methods of Examples 1 to 7 may further include a step of sorting the waste using at least one method selected from the group consisting of a method of sorting using differences in specific gravity, a method of sorting using differences in shape, a method of sorting using a sieve, and a method of sorting using eddy currents.

[0107] Example 9. An example of a clinker production method includes heating cement raw materials in a kiln using plastic materials separated from waste by any of the methods of Examples 1 to 8 as a thermal energy source in the kiln. In this case, the same effects as those of the method of Example 1 or Example 2 can be obtained.

[0108] Example 10. An example of a waste treatment system is a system for separating and treating waste to use plastic materials contained in the waste as a thermal energy source, comprising: a shredder configured to shred the waste to produce shredded material; a first magnetic separator configured to perform magnetic separation on the shredded material so that the magnetic flux density acting on the surface of the shredded material is 0.02 Tesla or more and 0.35 Tesla or less, thereby separating a first metal waste from the shredded material; and a second magnetic separator configured to perform magnetic separation on the residue obtained after the first metal waste is separated from the shredded material in the first magnetic separator so that the magnetic flux density acting on the surface of the residue is 0.85 Tesla or more and 2 Tesla or less, thereby separating a second metal waste from the residue. The chromium content in the second metal waste is greater than the chromium content in the first metal waste. In this case, the same effects as those of the method of Example 1 can be obtained.

[0109] Example 11. Another example of a waste treatment system is a waste treatment system that separates and processes waste to use plastic materials contained in the waste as a thermal energy source. The system includes: a crusher configured to crush the waste to produce crushed material; a first magnetic separator configured to perform magnetic separation on the crushed material so that the magnetic flux density acting on the surface of the crushed material is 0.02 Tesla or more and 0.35 Tesla or less, thereby separating a first metal waste from the crushed material; a thermal desalination furnace configured to heat the residue obtained after the first metal waste is separated from the crushed material in the first magnetic separator at 250°C or more and 450°C or less, thereby producing a desalted material; and a second magnetic separator configured to perform magnetic separation on the desalted material so that the magnetic flux density acting on the surface of the desalted material is 0.06 Tesla or more, thereby separating a second metal waste from the desalted material. The chromium content of the second metal waste is greater than the chromium content of the first metal waste. In this case, the same effects as those of the method of Example 2 can be obtained. [Explanation of symbols]

[0110] 1...clinker manufacturing equipment, 2...kiln equipment, 10...waste treatment system, 13...crusher, 14...magnetic separator (first magnetic separator), 15...magnetic separator (second magnetic separator), 19...thermal desalination furnace, D4...crushed material, D5...residue, D10...desalted material, M1...iron (first metal waste), M2...magnetic stainless steel (second metal waste), P...plastic material, W...waste, W1...cement raw material, W2...cement clinker (clinker).

Claims

1. 1. A waste treatment method for sorting and treating waste so that plastic materials contained in the waste can be used as a thermal energy source, comprising: a first step of crushing the waste to produce crushed material; a second step of performing magnetic separation on the crushed material so that the magnetic flux density acting on the surface of the crushed material is 0.02 Tesla or more and 0.35 Tesla or less, and separating the first metal waste from the crushed material; a third step of magnetically separating the residue after the first metal waste has been separated from the crushed material in the second step so that the magnetic flux density acting on the surface of the residue is 0.85 Tesla or more and 2 Tesla or less, and separating the second metal waste from the residue; A waste treatment method, wherein the chromium content in the second metal waste is greater than the chromium content in the first metal waste.

2. 1. A waste treatment method for sorting and treating waste so that plastic materials contained in the waste can be used as a thermal energy source, comprising: a first step of crushing the waste to produce crushed material; a second step of performing magnetic separation on the crushed material so that the magnetic flux density acting on the surface of the crushed material is 0.02 Tesla or more and 0.35 Tesla or less, and separating the first metal waste from the crushed material; a third step of heating the residue obtained after the first metal waste is separated from the crushed material in the second step at a temperature of 250°C or higher and 450°C or lower to produce a demineralized material; and a fourth step of performing magnetic separation on the desalted material so that the magnetic flux density acting on the surface of the desalted material is 0.06 Tesla or more, and separating second metal waste from the desalted material, A waste treatment method, wherein the chromium content in the second metal waste is greater than the chromium content in the first metal waste.

3. The method further comprises a fifth step of pulverizing the demineralized product produced in the third step, 3. The method according to claim 2, wherein the fourth step comprises performing magnetic separation on the desalted material after being pulverized in the fifth step to separate the second metal waste from the desalted material.

4. The method according to any one of claims 1 to 3, wherein the chromium content in the waste is 10 mg / kg or more and 14,000 mg / kg or less.

5. The method according to any one of claims 1 to 3, wherein the chromium content in the residue after the second metal waste is separated is 12000 mg / kg or less.

6. The method according to any one of claims 1 to 3, wherein the waste material contains chromium-containing materials that are magnetic.

7. The method according to any one of claims 1 to 3, wherein the waste material comprises at least one selected from the group consisting of shredder dust, automobile shredder dust, and waste plastics.

8. The method according to any one of claims 1 to 3, further comprising a step of sorting the waste by at least one method selected from the group consisting of a method of sorting using differences in specific gravity, a method of sorting using differences in shape, a method of sorting using a sieve, and a method of sorting using eddy currents.

9. 4. A method for producing clinker, comprising heating cement raw materials in a kiln system using the plastic material separated from the waste by the method according to any one of claims 1 to 3 as a thermal energy source in the kiln system.

10. A waste treatment system for sorting and treating waste so that plastic materials contained in the waste can be used as a thermal energy source, comprising: a shredder configured to shred the waste material to generate shredded material; a first magnetic separator configured to perform magnetic separation on the crushed material so that the magnetic flux density acting on the surface of the crushed material is 0.02 Tesla or more and 0.35 Tesla or less, and to separate a first metal waste from the crushed material; a second magnetic separator configured to perform magnetic separation on the residue after the first metal waste has been separated from the crushed material in the first magnetic separator so that the magnetic flux density acting on the surface of the residue is 0.85 Tesla or more and 2 Tesla or less, and to separate the second metal waste from the residue; A waste treatment system, wherein the chromium content in the second metal waste is greater than the chromium content in the first metal waste.

11. A waste treatment system for sorting and treating waste so that plastic materials contained in the waste can be used as a thermal energy source, comprising: a shredder configured to shred the waste material to generate shredded material; a first magnetic separator configured to perform magnetic separation on the crushed material so that the magnetic flux density acting on the surface of the crushed material is 0.02 Tesla or more and 0.35 Tesla or less, and to separate a first metal waste from the crushed material; a thermal desalination furnace configured to heat the residue remaining after the first metal waste is separated from the crushed material in the first magnetic separator at a temperature of 250°C or higher and 450°C or lower to produce a desalted material; a second magnetic separator configured to perform magnetic separation on the desalted material so that the magnetic flux density acting on the surface of the desalted material is 0.06 Tesla or more, and to separate second metal waste from the desalted material; A waste treatment system, wherein the chromium content in the second metal waste is greater than the chromium content in the first metal waste.

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