Metal recovery method

Abstract

To provide a metal recovery method that makes it possible to efficiently recover metals from wastes of electronic apparatuses and the like.SOLUTION: A metal recovery method comprises a rough dismantling process that roughly disassembles a raw material, a primary magnetic separation process that sorts iron using magnets, an X-ray optical sorting process that sorts aluminum, a crushing process that reduces the raw material to a granular form, a secondary magnetic separation process that sorts iron using magnets, a stainless steel sorting process that uses air to blow away stainless steel detected by an electromagnetic induction sensor, and a separation process that sorts the stainless steel sorted raw material into metal and non-metal using eddy currents, followed by a copper sorting process that sorts copper from the metals sorted by eddy currents and a brass sorting process that sorts brass from the metals that copper was sorted from.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a metal recovery method for recovering metals from discarded equipment such as water heaters, gas meters, and electricity meters. [Background technology]

[0002] In recent years, the recovery of precious metals from circuit boards of discarded home appliances, personal computers, mobile phones, etc. has become common. For this reason, the development of more efficient methods for recovering metals is desired.

[0003] Conventionally, one such technique has been proposed in Patent Document 1. Patent Document 1 discloses a method for treating scrap electric and electronic components, including a step of subjecting plastic-containing scrap electric and electronic components generated during a sorting process to a specific gravity sorting process using salt water, and separating and recovering valuable plastic scraps. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-166728 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when removing substrates from waste having a metal housing, such as a water heater, a gas meter, or an electric meter, workers dismantle the waste and separate the metal housing to remove the substrates. However, this dismantling work is not easy, so it is difficult to remove a large amount of substrates from a large amount of waste. Therefore, it is possible to crush the metal housing using a crusher and then remove the substrates. However, when crushing the metal housing, the substrates are also crushed into small pieces, which may make it difficult to recover the metals from the substrates. Moreover, other metals are also crushed too small, making recovery difficult, and other metals may be mixed with the metal to be recovered in the subsequent process, which may reduce the purity of the recovered metal.

[0006] Due to these problems, the reality is that residual scrap has been exported to other countries, such as Southeast Asia. However, the Malaysian Ministry of International Trade and Industry (MITI) recently announced that the quality standards for the import of iron, copper, and aluminum scrap will come into effect on January 10, 2022. According to this announcement, scrap that does not meet the standards of a yield of 94.75% or more and a foreign matter contamination rate of 0.25% or less will be prohibited from being imported in principle, and the inclusion of waste circuit boards, electrical and electronic components, etc. is completely prohibited. In Japan, about 30% of the total export volume of copper and aluminum scrap is exported to Malaysia, and taking into account the issue of domestic urban mine resource circulation, more efficient metal recovery from waste is an urgent issue.

[0007] An object of the present invention is to provide a metal recovery method that solves these problems and enables more efficient recovery of metals from waste electronic devices and the like. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention has the following configuration.

[0009] (1) a rough dismantling process in which the exterior of the raw material is destroyed to separate the exterior from the substrate; a first magnetic separation step carried out after this step, in which iron is separated using a magnet; This process is followed by an X-ray optical sorting process to separate the aluminum. A crushing process is carried out after this process, in which the raw material is crushed into granules; a second magnetic separation step performed after this step, in which iron is separated using a magnet; A stainless steel sorting process is carried out after the above process, in which stainless steel detected by the electromagnetic induction sensor is blown away with air to separate the stainless steel. This process is followed by a waste plastic removal process in which metals and non-metals are separated using eddy currents and the non-metals are removed. a copper separation step carried out after this step, in which copper is separated from the separated metal by eddy currents; and a brass separation step carried out after this step to separate brass from the copper separating metals.

[0010] According to (1), in the rough dismantling process, the exterior of the raw material (e.g., the housing) is destroyed (rough dismantling) to separate the exterior from the substrate, so that the substrate can be extracted without crushing it into smaller pieces than necessary. This makes it possible to efficiently extract precious metals from the substrate. In addition, after the raw material is automatically broken down into pieces of appropriate size in the rough dismantling process, iron is extracted using a magnetic separator, and then aluminum is extracted using an X-ray optical sorter. As a result, the raw material passes through the X-ray optical sorter with iron removed, so that identification errors in the X-ray optical sorter can be suppressed. The metals extracted up to this point do not proceed to the next process of crushing by a hammer separating crusher, so that the metals extracted up to this point are not crushed.

[0011] The raw materials from which the iron, substrate, and aluminum have been extracted are crushed and granulated by a hammer separation crusher. The remaining raw materials (copper, stainless steel, plastic, etc.) after the substrate, iron, and aluminum have been separated are crushed together with the raw materials by the hammer separation crusher, which breaks down the state of dissimilar metals (a composite material in which metals of different elements are physically bundled together and entangled with each other, which is different from the state of a metal-like alloy made up of multiple metal elements or metal elements and nonmetallic elements) into separate pieces that are easy to separate, and are then sorted into high-content pieces in the next process.

[0012] As described above, iron and aluminum are removed before the raw material is granulated, which reduces the amount of iron and aluminum particles remaining in the granulated raw material. This reduces the reduction in purity due to iron and aluminum when copper, brass, etc. are extracted after granulation.

[0013] According to (1), a metal recovery method can be provided that enables more efficient recovery of metals from waste electronic devices and the like.

[0014] (2) In paragraph (1), The rough dismantling step is a metal recovery method in which the exterior of a discarded device, which is a raw material, is crushed, and then the exterior is separated from the substrate attached to the exterior.

[0015] According to (2), in the rough dismantling process, the exterior of the discarded equipment is crushed, so that the substrates are not crushed into small pieces, and the exterior and substrate can be separated, so that the equipment can be roughly dismantled in a state in which the substrates can be easily removed. Effect of the Invention

[0016] According to the present invention, it is possible to provide a metal recovery method that enables more efficient recovery of metals from waste electronic devices and the like. [Brief description of the drawings]

[0017] [Figure 1]FIG. 2 is an explanatory diagram of a metal recovery method according to the present embodiment. [Diagram 2] FIG. 2 is an explanatory diagram showing the internal configuration of the metal equipment rough dismantling machine 1. [Diagram 3] FIG. 2 is an explanatory diagram showing the appearance of a metal twister 11. [Figure 4] FIG. 2 is a schematic diagram showing an outline of an electromagnetic induction eddy current composite sorting machine 20. [Diagram 5] FIG. 2 is an explanatory diagram showing a metal recovery method according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0019] FIG. 1 is an explanatory diagram showing each step constituting an embodiment of the metal recovery method of the present invention.

[0020] <Each step in the metal recovery method> The metal recovery method of the present invention aims to recover as many valuable metals as possible from "equipment with circuit boards embedded in equipment derived from demolished houses" and "miscellaneous industrial metal equipment" which contain circuit boards and metals but are difficult to recover and have been exported as scrap until now, thereby improving the recovery rate of copper, aluminum, stainless steel, and precious metals, among others, while at the same time increasing the circulation of domestic urban mine resources.

[0021] The metal recovery method of the present invention separates and recovers various metals such as copper, aluminum, stainless steel, and precious metals from various miscellaneous items consisting of substrates, metal casings, plastic casings, etc., including metal miscellaneous items (devices with built-in substrates and miscellaneous industrial metal equipment) derived from house demolition that are difficult to recycle and are disposed of in landfills. Examples of devices with built-in substrates derived from house demolition include water heater controllers, gas meters, electric meters, intercoms, etc. Examples of miscellaneous industrial metal equipment include personal computers, large computers, water heater bodies, etc. Among them, there was a problem that devices with built-in substrates derived from house demolition cannot be dismantled in the first place because the casings are relatively small and hard, or the built-in substrates are reduced to pieces, making it impossible to recover the substrates. The present invention solves this problem.

[0022] In the following explanation, "all miscellaneous items consisting of circuit boards, metal casings, plastic casings, etc., including metal miscellaneous items derived from house demolitions" will be referred to as raw materials.

[0023] 1 is an explanatory diagram of a metal recovery method according to the present embodiment. This method includes at least a rough dismantling process for roughly dismantling raw materials, a first magnetic sorting process for sorting iron using a magnet, an X-ray optical sorting process for sorting aluminum, a crushing process, a second magnetic sorting process for sorting iron using a magnet, a stainless steel sorting process using an electromagnetic induction eddy current composite sorter, a copper sorting process using a color sorting device, and a brass sorting process using a color sorting device, and each process is performed in this order to recover metals from raw materials. If the processes are not performed in this order, the yield of some elements may be low or the cost efficiency may be reduced when recovering metals from board-embedded devices and industrial miscellaneous metal devices, so a recovery method other than this order is not preferable in this embodiment.

[0024] In addition, although not essential, the method preferably includes an X-ray AI sorting step between the first magnetic sorting step and the X-ray optical sorting step (after the first magnetic sorting step and before the X-ray optical sorting step). By performing the X-ray AI sorting step, more accurate and efficient sorting becomes possible.

[0025] [Rough demolition process] The rough dismantling process is carried out by a metal equipment rough dismantling machine. The raw materials are transported by a belt conveyor, and the raw materials are separated and supplied to the metal equipment rough dismantling machine by transporting the raw materials while vibrating the surface. The metal equipment rough dismantling machine is equipped with a metal twister and a chain crusher inside, and the raw materials are roughly dismantled by the rotation of the metal twister and the chain crusher.

[0026] [Configuration of metal equipment rough dismantling machine] 2 is an explanatory diagram showing the internal configuration of the metal equipment rough dismantling machine 1. The metal equipment rough dismantling machine 1 is equipped with a cylindrical crushing chamber 5 having a supply port 2 for feeding raw materials at the top and a discharge port 3 for discharging roughly dismantled raw materials at the bottom, an image recognition sensor 10, a metal twister 11, a chain crusher 12, a motor 13, and a rotating shaft 14. The image recognition sensor 10, the metal twister 11, the chain crusher 12, and the rotating shaft 14 are arranged inside the crushing chamber 5, the image recognition sensor 10 is installed at the supply port 2, the metal twister 11 is arranged below the supply port 2, and the chain crusher 12 is arranged below the metal twister 11. The rotating shaft 14 is erected at the bottom of the crushing chamber 5, the metal twister 11 is fixed to the tip of the rotating shaft 14, and the chain crusher 12 is fixed to the lower part of the rotating shaft 14.

[0027] The image recognition sensor 10 takes an image of the raw material fed into the supply port 2, recognizes the shape of the fragments, etc., and transmits the data to the computer that controls the metal equipment rough dismantling machine 1. Based on the data from the image recognition sensor 10, the computer calculates the knock speed (the speed at which the metal twister 11 strikes) that corresponds to the size of the original material that has been learned and recorded in advance, and by controlling the speed, the raw material can be efficiently crushed without crushing the substrate into smaller pieces than necessary.

[0028] FIG. 3 is an explanatory diagram showing the appearance of the metal twister 11. The metal twister 11 includes an engagement portion 11a that engages with the rotating shaft 14, and four impact portions 11b arranged on the outer periphery of the engagement portion 11a. The engagement portion 11a includes a hexagonal column-shaped hole that is inserted into the rotating shaft 14 and engages with the tip of the rotating shaft 14 at its center. The impact portion 11b includes a support extending radially from the center of the engagement portion 11a, and a substantially rectangular parallelepiped impact body attached to the tip of the support. The impact surface of the impact body faces in a direction that revolves around the central axis of the engagement portion 11a. Ribs extending along the rotation direction are provided on the side disposed on the upper side and the side disposed on the outside among the four side surfaces of the impact body. The outer diameter of the metal twister 11 is set to, for example, 1 / 4 to 1 / 2, preferably 1 / 3, of the inner diameter of the crushing chamber 5. That is, a predetermined gap is provided between the striking part 11b of the metal twister 11 and the crushing chamber 5. The gap between the striking part 11b of the metal twister 11 and the crushing chamber 5 is desirably about the size of the substrate, and is set to, for example, 30 cm. Since most substrates are about 25 cm in size, if the gap between the striking part 11b of the metal twister 11 and the crushing chamber 5 is about 28 to 32 cm, the substrate can pass between the metal twister 11 and the crushing chamber 5 and fall.

[0029] The chain crusher 12 has two chains, and these two chains are fixed to the rotating shaft 14. The material of the chain is not particularly limited, but is preferably a manganese steel chain. By using a manganese steel chain, the raw material can be uniformly hit by the hammer, and durability is increased. When the chain is extended in the radial direction, the end of the chain extends close to the inner surface of the crushing chamber 5 and does not reach the inner surface of the crushing chamber 5. According to this embodiment, there is a space of about 15 cm between the end of the chain and the inner surface of the crushing chamber 5. The chain crusher 12 has a smaller force to crush the exterior of the raw material than the metal twister 11, but can apply a force to the raw material that is sufficient to separate the connecting portion (for example, the screw-fastened portion) between the exterior of the raw material and the substrate. The number of chains of the chain crusher 12 can be appropriately set according to the thickness and weight of the chain, but it is preferable to have one or two chains in order to prevent the substrate from being crushed more than necessary, and more preferably two chains.

[0030] The motor 13 is disposed outside the crushing chamber 5. When the motor 13 rotates, the rotation is transmitted to the rotating shaft 14, and the rotating shaft 14 rotates inside the crushing chamber 5. When the rotating shaft 14 rotates, the metal twister 11 and the chain crusher 12 rotate.

[0031] Next, the rough dismantling of raw materials by the metal equipment rough dismantling machine 1 will be described.

[0032] The size of the raw materials is within 80 cm, and each piece weighs less than 50 kg. The raw materials are transported by a belt conveyor and fed into the crushing chamber 5 from the supply port 2. The crushing speed of the metal equipment rough dismantling machine 1 is within 200 rotations per hour, and it has a maximum processing capacity of 5,000 kg per hour.

[0033] The raw material fed from the supply port 2 falls near the center of the metal twister 11. It is then struck by the rotating metal twister 11 and crushed while moving up and down. The crushed pieces are struck against the inner wall of the crushing chamber 5 by centrifugal force, and the raw material breaks into pieces. At the same time, the collision of the crushed pieces with each other can peel off the adhesions and paint on the surface of the crushed pieces. Once the raw material is broken to a certain extent, it falls freely between the metal twister 11 and the crushing chamber 5. The fallen raw material is struck by the chain crusher 12 and broken down into each material, for example, the exterior and the base plate.

[0034] That is, when the raw materials pass through the metal twister 11, for example, the exterior of a water heater or an electric meter is crushed, but the substrate is not yet crushed. When the exterior is crushed, the raw materials fall to the side of the chain crusher 12 together with the substrate. Then, the chain crusher 12 hits the raw materials, separating the exterior and the substrate, and dismantling each material is performed in a manner similar to manual dismantling. The dismantled raw materials are discharged from the discharge port 3. In this way, it is possible to discharge the substrates of water heaters, gas meters, electric meters, etc. without significantly crushing them, and in a state where the substrates are separated from other components such as the exterior. This makes it possible to recover substrates in a less crushed state from the roughly dismantled raw materials, improving the circulation and recovery rate of precious metals from the substrates.

[0035] The height of the discharge port 3 can be adjusted in multiple steps (three steps in the present embodiment, but not limited to this) in the vertical direction, and the size of the raw material to be discharged can be adjusted. Also, the rotation speeds of the metal twister 11 and the chain crusher 12 are controlled based on the detection results of the image recognition sensor 10.

[0036] In addition, in the above-mentioned metal equipment rough dismantling machine 1, the metal twister 11 is arranged at the top and the chain crusher 12 is arranged at the bottom, but it is not desirable to arrange the chain crusher 12 at the top and the metal twister 11 at the bottom. In this case, the raw material is finely crushed in a state where the substrate and the exterior are mixed, so that in the later process, the purity of the material may decrease due to the coexistence of dissimilar metal bond pieces and aluminum powder, and stainless steel and cables may be included in the waste plastics sorted when using an eddy current sorter, which makes it difficult to recover precious metals such as gold and silver and rare metals from the substrate. Therefore, by arranging the metal twister 11 at the top and the chain crusher 12 at the bottom, it is possible to sort the substrate in a relatively large state without crushing it more than necessary, making it easier to remove gold, silver, and rare metals from the substrate. This improves the recovery efficiency of precious metals such as gold and silver and rare metals from the substrate.

[0037] In addition, precious metals are rare metals that are difficult to form compounds with, and generally refer to eight types: gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and osmium.

[0038] Furthermore, rare metals refer to non-ferrous metals used in industry other than base metals (also called common metals or major metals) such as iron, copper, zinc, aluminum, etc., and precious metals such as gold, silver, etc. Specific examples of rare metals include lithium, beryllium, boron, titanium, vanadium, chromium, manganese, cobalt, nickel, gallium, germanium, selenium, rubidium, strontium, zirconium, niobium, molybdenum, palladium, indium, antimony, tellurium, cesium, barium, hafnium, tantalum, tungsten, rhenium, thallium, bismuth, scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Among them, scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium are also called rare earth elements (rare earths).

[0039] Conventionally, rough dismantling using a single chain crusher has been carried out. However, although rough dismantling using a single chain crusher was able to handle the rough dismantling of the boxes and casings of information devices, it was not sufficient for the rough dismantling of miscellaneous industrial items or the rough dismantling of water heaters, gas meters, electric meters, etc., resulting from the demolishment of houses, in terms of whether or not the circuit boards could be extracted in a form that enabled the recovery of precious metals.

[0040] According to this method, by providing an image recognition sensor 10 and a metal twister 11 upstream of a chain crusher 12, it is possible to solve the problem that it was impossible to dismantle the wastewater treatment plant or that the wastewater treatment plant including its built-in circuit boards was blown into pieces and the circuit boards could not be recovered in a form that allows the precious metals to be recovered.

[0041] Cross-flow shredders are also known as crude dismantling devices, but this method has the advantage over cross-flow shredders in that a metal twister with ultra-hard blades is placed on the upper stage, making it easy to tear apart even hard casings, and a chain crusher with adjusted rotation speed in the rear stage crushes the raw materials to loosen them, reducing the chance of circuit boards getting caught or entangled inside the casing and allowing the elements to be separated while still attached to the circuit board.

[0042] [First magnetic separation process] The raw materials that have been roughly dismantled through the rough dismantling process are transported by a conveyer belt towards the magnetic separator. Then, by bringing the magnetic poles of the magnetic separator close to the raw materials, the iron is attracted to the magnetic poles of the magnetic separator and separated. The separated iron is accumulated in a designated location, and the raw materials that are not attracted to the magnetic separator are placed on the conveyer belt and sent to the X-ray AI sorter. At this time, the conveyer belt is vibrated, so the raw materials on the conveyer belt are separated as they are transported.

[0043] Of the metal miscellaneous products derived from house demolition that are supplied as raw materials, approximately 70% can be recovered as iron, and approximately 30% as non-ferrous metals are sent to the X-ray AI sorter. Because the X-ray AI sorter and the X-ray optical sorter used in the subsequent process have high equipment costs, it is preferable to keep the amount of material supplied to the X-ray AI sorter as low as possible. From this point of view, it is preferable to adopt a primary magnetic sorting process as an initial separation step and separate the raw materials into iron and non-ferrous metals.

[0044] In addition, if the raw materials contain large iron particles before the X-ray AI sorting process is carried out, the iron may become an obstacle when sorting the substrates, and the substrates may not be sorted properly. Also, since the X-ray AI sorting machine is a relatively precise machine, there is a risk that the sorting performance will not be fully realized if iron is mixed in. For this reason, it is preferable to carry out the X-ray AI sorting process after the first magnetic sorting process.

[0045] [X-ray AI sorting process] Although not essential, the method according to the present embodiment preferably includes an X-ray AI sorting step between the first magnetic sorting step and the X-ray optical sorting step (after the first magnetic sorting step and before the X-ray optical sorting step). By performing the X-ray AI sorting step, more accurate and efficient sorting becomes possible.

[0046] The X-ray AI sorting machine finds and separates circuit boards from the raw materials. For example, small devices and wiring attached to printed circuit boards contain valuable metals such as multiple types of precious metals and rare metals, so it is preferable to recover the circuit boards as circuit boards while retaining their shape as much as possible. In this respect, it is preferable to keep the degree of dismantling in the rough dismantling process to a minimum. If the raw materials are dismantled too finely, the crushed material of the circuit boards will be mixed with base metals such as iron, copper, zinc, and aluminum, and it is not preferable to be unable to recover the precious metals and rare metals contained in the circuit boards as precious metals or rare metals.

[0047] The X-ray AI sorting machine recognizes the shape and color of an object to determine whether it is a circuit board or not. The control device installed in the X-ray AI sorting machine is equipped with an artificial intelligence acceleration algorithm and has a garbage identification function (AI learning ability function) using garbage high-end sensor images. This allows it to achieve a sorting accuracy of over 98% at a sorting speed of 4,000 times per hour.

[0048] Any objects determined to be circuit boards are sprayed with high-pressure gas and blown off the conveyor, where the circuit boards are sorted. The materials that have passed through the X-ray AI sorting machine and from which the circuit boards have been removed are placed on a conveyor belt and sent to the X-ray optical sorting machine. At this time, the conveyor belt is vibrated, so that the materials on the conveyor belt are separated as they are transported. The sorted circuit boards are sent to equipment that recovers the precious metals from the substrates.

[0049] Approximately 7% of the raw materials that have gone through the rough dismantling process can be recovered as substrates, and approximately 93% other than substrates is sent to an X-ray optical sorting machine. Substrates selected in the X-ray AI sorting process are crushed and sorted using known processes as urban mine raw materials. This crushing and sorting process yields precious metals (gold, silver, palladium) and copper particles.

[0050] [X-ray optical sorting process] The X-ray optical sorter takes an X-ray image of the raw material supplied from the X-ray AI sorter, and separates the raw material into aluminum and non-aluminum based on the difference in atomic density. Aluminum has a relatively low atomic density compared to other metals. By utilizing this property, the X-ray optical sorter can separate the raw material into aluminum (light metal) and other materials (non-light metals).

[0051] In addition to aluminum, magnesium, beryllium, titanium, alkali metals and alkaline earth metals (except radium) also have relatively low atomic densities, and it is preferable to avoid separating these light metals contained in the substrate as aluminum. Therefore, it is preferable to provide an X-ray AI sorting process prior to the X-ray optical sorting process, and to remove metals derived from the substrate in advance from the raw materials supplied to the X-ray optical sorting process.

[0052] Of the raw materials that undergo the X-ray AI sorting process, approximately 11% can be recovered as aluminum, and approximately 89% of the non-aluminum materials are sent to the hammer separation crusher.

[0053] According to this method, about 75% of the circuit board-embedded devices and miscellaneous industrial metal devices derived from house demolition are sorted into valuable metals through the rough dismantling process, the first magnetic sorting process, the X-ray AI sorting process, and the X-ray optical sorting process. The equipment used in the subsequent processes is less efficient in terms of both processing speed and equipment cost compared to the equipment used in the rough dismantling process, the first magnetic sorting process, the X-ray AI sorting process, and the X-ray optical sorting process, so it is preferable to recover as many metals as possible between these processes. With this method, about 75% has already been separated, and the amount of raw material used in the subsequent processes is limited to about 25%, making this a preferable process.

[0054] [Crushing process] The raw materials, from which aluminum has been removed through the X-ray optical sorting process, are crushed in a hammer separation crusher. The crusher is a device that combines 16 hammers in a four-stage vertical configuration, and the roughly disassembled raw materials are hammered from the top stage to the bottom stage in order to loosen and separate them, and then crushed into uniform sizes (2 to 3 cm). The top stage hammers the coarsest of the four stages, and the lower stages hammer smaller and smaller. Finally, in the fourth and final stage, the materials are broken down into individual pieces and become separated from each other. The crusher body, hammer head, hob, liner, etc. in the crusher are all made of high-strength, high-toughness manganese steel, and the more they are hit with the hammer, the higher the surface hardness becomes.

[0055] In the crushing process, it is preferable that a hammer separating crusher successively loosens and separates the roughly disassembled raw materials, and then crushes the raw materials finely. This makes it possible to maintain the size of the raw materials after crushing uniform, and to prevent metals of different elements from remaining in a physically aggregated state (a state of composite materials in which they are entangled with each other), making it possible to realize high-purity sorting for each type of metal element in the process after the crushing process. For example, with a conventionally known two-stage vertical 12-piece hammer crusher, the purity of the recovered metals is only about 98%, but with the crushing method used in this method, metals with a purity of over 99% can be recovered.

[0056] In addition, if the raw materials are crushed into small pieces all at once, frictional heat will increase, and the oxidation of the metals contained in the raw materials will progress. Since this method includes sorting using a color sorting device in the post-process, it is preferable to crush the raw materials in stages to minimize the progression of oxidation.

[0057] In addition, the raw material after the aluminum is sorted out by the X-ray optical sorter is finely crushed in the crushing process. If the aluminum is sorted out by the X-ray optical sorter after the crushing process, there is a risk that the aluminum will be powdered in the crushing process. Aluminum has a large combustion heat among metals, and when powdered, it is easily oxidized due to its large surface area, and there is a risk of explosion when it comes into contact with acid, water, alcohol, oxidizing agents, etc. In addition, the atomic density of aluminum oxide is about 1.4 times that of aluminum, which exceeds the range of atomic density of light metals, making it difficult to recover it with the X-ray optical sorter. For this reason, it is preferable to finely crush the raw material in the crushing process after the aluminum is sorted out.

[0058] [Secondary magnetic separation process] By bringing the magnetic poles of the magnetic separator close to the raw materials that have been crushed to roughly uniform sizes through the crushing process, the iron that was not completely separated in the first magnetic separation process is attracted to the magnetic poles of the magnetic separator and separated out. The separated iron is accumulated in a designated location. The raw materials that are not attracted to the magnetic separator are sent to the electromagnetic induction eddy current combined separator.

[0059] Of the raw materials that have gone through the crushing process, approximately 8% can be recovered as iron with a purity of 99.5%, and approximately 92% is sent to an electromagnetic induction eddy current composite sorting machine as non-ferrous metals.

[0060] [Stainless steel sorting process] From the process thus far, the raw materials mainly contain non-metals and plastics from which iron, aluminum and precious metals have been removed from the circuit board-embedded devices originating from demolished buildings. Here, the raw materials may contain iron, aluminum and precious metals that could not be completely separated from the process thus far. Moreover, "mainly" means that the total content is high, and in this specification, it means that the content of non-metals and plastics is higher than the content of iron, aluminum and precious metals.

[0061] In the stainless steel sorting process, stainless steel is detected by an electromagnetic induction sensor and then blown away with air to separate the stainless steel.

[0062] [Waste plastic removal process] In the waste plastic removal process, after the stainless steel sorting process, metals and non-metals are separated using eddy currents, and the non-metals are removed.

[0063] An example of equipment that can realize the stainless steel sorting process is an electromagnetic induction type AI sorting device, and an example of equipment that can realize the waste plastic removal process is an eddy current sorting machine. However, it is more preferable to use an electromagnetic induction eddy current combined sorting machine that integrates these electromagnetic induction type AI sorting devices and eddy current sorting machines. By using an electromagnetic induction eddy current combined sorting machine, the following advantages are obtained: (1) it is cheaper overall than purchasing each device separately, (2) it saves space compared to installing each device separately, and (3) it is more energy efficient than using each device separately, which leads to CO2 reduction.

[0064] In the following, an explanation will be given on the assumption that an electromagnetic induction eddy current composite sorting machine is used in the stainless steel sorting process and the waste plastic removal process.

[0065] [Electromagnetic induction eddy current composite sorter 20] 4 is a schematic diagram showing an overview of an electromagnetic induction eddy current composite sorting machine 20, which includes an upper induction sorting section 21 and a lower eddy current metal sorting section 22. The induction sorting section 21 corresponds to the stainless steel sorting process, and the eddy current metal sorting section 22 corresponds to the waste plastic removal process.

[0066] (Induction Selection Unit 21) The induction sorting unit 21 includes a belt conveyor 211 for transporting the raw materials, an induction sensor 212 installed under the downstream end of the belt conveyor 211 in the transport direction, a high-pressure valve 213 provided at the downstream end of the belt conveyor 211 in the transport direction, an image sensor 214 arranged upstream of the induction sensor 212 in the transport direction of the belt conveyor 211, and a computer (not shown). The high-pressure valve 213 is configured in an array with multiple valves lined up in a row, and is capable of injecting high-pressure air at pinpoint accuracy at the raw materials dropped from the downstream end of the belt conveyor 211 in the transport direction, thereby blowing away the object to be sprayed.

[0067] In the induction sorting unit 21, a computer detects induction metals, particularly stainless steel, contained in the raw materials based on the shape and color of the raw materials shown in the image of the raw materials captured by the image sensor 214, and further, the induction sensor 212 detects induction metals, particularly stainless steel, contained in the raw materials. Then, based on the detection results of the image sensor 214 and the detection results of the induction sensor 212, the computer drives the high-pressure valve 213 at the timing when the stainless steel falls from the belt conveyor 211, and the stainless steel is blown away by air pressure, thereby separating the stainless steel from the raw materials.

[0068] The computer executes a process (raw material identification process) including an image acquisition step of acquiring a captured image, an image input step of inputting the acquired image into a predetermined neural network (raw material identification neural network), and a material acquisition step of acquiring the material of the raw material included in the image output from the raw material identification neural network. The computer includes at least a control unit exemplified by a Central Processing Unit (CPU) or the like, a memory unit exemplified by a Random-access memory (RAM), a Read-only memory (ROM), various storage devices, etc., in which a program for executing the above process and the raw material identification neural network are stored, and a communication unit that outputs the acquired raw material material, etc. to the outside. The raw material identification neural network is a neural network related to image recognition that has been pre-trained using learning data that includes the captured image as an explanatory variable and the material of the raw material as a target variable. In order to select stainless steel with high accuracy, it is preferable that the raw material identification neural network is configured to at least identify whether the raw material is stainless steel or not.

[0069] The induction sensor 212 may erroneously recognize the type of metal constituting the main part of the raw material due to the shape of the raw material (wire material, foil material, etc.), the induced metal contained in the raw material (circuits, elements, etc. of a printed circuit board), and other factors. The induction sorting unit 21 of this embodiment is capable of detecting stainless steel that cannot be accurately detected by the induction sensor 212 alone, by using information from the image sensor 214 and the induction sensor 212. Furthermore, the induction sorting unit 21 of this embodiment is capable of determining that raw material that would be erroneously detected as stainless steel by the induction sensor 212 alone is not stainless steel, by using information from the image sensor 214 and the induction sensor 212.

[0070] Although not essential, it is preferable that the raw material identification neural network has been pre-trained to further include the shape of the raw material as a target variable. This makes it possible to calculate different drive conditions for the high-pressure valve 213 depending on the shape. In addition, the manager of the metal equipment rough dismantling machine 1 can adjust the drive conditions for the high-pressure valve 213 by referring to the shape of the raw material output from the raw material identification neural network. This is expected to facilitate the work of blowing the selected material to an appropriate location.

[0071] It is preferable that the computer executes a drive condition calculation step of calculating appropriate drive conditions for the high-pressure valve 213 based on the detection results based on the image sensor 214 and the detection results by the induction sensor 212. The drive conditions are, for example, the air ejection speed (knock speed) when blowing the raw materials to an appropriate place according to the material and shape of the raw materials using the above-mentioned high-pressure valve 213. The raw materials passing through the induction sorting unit 21 have different sizes, materials, weights, etc. Therefore, if the high-pressure valve 213 does not blow the raw materials under appropriate drive conditions, the raw materials will not be blown to an appropriate place according to the material. By executing the drive condition calculation step by the computer, the high-pressure valve 213 can blow the raw materials to an appropriate place according to the material and shape of the raw materials even if the manager of the metal equipment rough dismantling machine 1 does not manually adjust the drive conditions one by one. Note that the computer that executes the drive condition calculation step may be configured as a first computer that executes processing related to the image sensor 214 and a second computer that executes processing related to the induction sensor 212, which are separate computers. This allows the manager of the metal equipment rough dismantling machine 1 to maintain and adjust the computer for each sensor.

[0072] As a result of the induction sorting section 21 being configured as described above, the sorting accuracy of stainless steel was approximately 90% when only the induction sensor 212 was used, but by adding the image sensor 214, the sorting accuracy was improved to 99% or more. The sorted stainless steel is accumulated in a predetermined location outside the electromagnetic induction eddy current combined sorting machine 20. The raw materials from which stainless steel has been sorted in the induction sorting section 21 drops onto the belt conveyor 222 of the eddy current metal sorting section 22 at the lower level.

[0073] The detection target of the induction sensor 212 is a metal having electrical conductivity. Specifically, it detects induction metals such as copper, aluminum, zinc, lead, stainless steel, printed circuit boards (PCBs), and insulated wires. The detection distance varies depending on the type of metal, and the operating distance is long for magnetic metals such as iron, and is short for non-magnetic metals such as stainless steel, copper, and brass. However, in order to reliably avoid the mixing of non-magnetic metals such as stainless steel and magnetic metals such as iron, it is preferable that the raw materials are passed through the induction sensor 212 with as much iron removed as possible from the raw materials. In this respect, it is preferable that the stainless steel sorting process is positioned downstream of the second magnetic sorting process.

[0074] Of the raw materials that have undergone the second magnetic separation step, approximately 8% can be recovered as stainless steel, and approximately 92% is sent to the eddy current metal separation section 22 as materials other than stainless steel.

[0075] (Eddy current type metal sorting unit 22) The eddy current type metal sorting section 22 is made up of a rotating magnet roller type magnetic separator 221, which generates a magnetic field by eddy current and is capable of magnetically sorting iron, copper, aluminum, zinc, lead, and electric wires flowing on the belt conveyor 222. When passing through the eddy current type metal sorting section 22, the metals, including copper, brass, and iron and aluminum that could not be fully recovered in the previous process, are separated from the other non-metals such as plastics.

[0076] The eddy current metal sorting unit 22 only has the function of separating metals from non-metals, and does not have the ability to pinpoint a specific metal. For this reason, sorting by the eddy current metal sorting unit 22 is preferably used to separate raw materials into metals and non-metals after many types of metals have been sorted out.

[0077] Of the raw materials that pass through the induction sensor 212, approximately 42% can be recovered as plastic (non-metal), and approximately 58% is sent to a color sorting device as non-stainless steel (metal).

[0078] The plastics separated by the eddy current type metal sorting unit 22 are separated and sorted by known process into each plastic material, for example, acrylonitrile butadiene styrene resin (ABS resin), polypropylene resin (PP resin), polyethylene resin (PE resin), polystyrene resin (PS resin), polyvinyl chloride resin (PVC resin), etc. The separated and sorted materials are sold as plastic recycling materials or chemically treated to become resin product materials or recycled resin products.

[0079] The metals separated by the eddy current metal sorting section 22 are transported to the color sorting device for the next process, and non-metals are accumulated in a specified location outside the electromagnetic induction eddy current combined sorter 20. In this way, the electromagnetic induction eddy current combined sorter 20 is composed of two stages, the upper stage induction sorting section 21 and the lower stage eddy current metal sorting section 22, so that it is possible to achieve greater space savings than if two machines were installed.

[0080] [Copper sorting process] The metals separated through the eddy current metal sorting section are passed through a color sorting device.

[0081] Among the metals contained in the raw materials, magnetic metals such as iron are easy to separate and recover using a magnetic separator, but non-magnetic metals such as copper are more difficult to separate and recover than magnetic metals. In this method, the property of copper being red is utilized to separate the raw materials fed to a color sorting device into copper and non-copper components.

[0082] The colour sorting machine is a multi-stage machine: the first stage separates red from non-red and copper from non-copper.

[0083] Here, copper has a property of discoloring due to oxidation. Depending on the degree of oxidation, copper changes color from reddish brown to brown to dark brown to blackish brown to green-blue. Therefore, it is preferable to provide multiple color sorting devices and recover copper according to the stage of unbalanced consumption. This makes it possible to recover copper contained in the raw material more reliably. The separated copper is accumulated in a specified location outside the color sorting devices.

[0084] Of the raw materials that have gone through the stainless steel sorting process, approximately 66% can be recovered as 99% pure copper, and approximately 32% other than copper is sent to the next process, the color sorting device.

[0085] [Brass sorting process] After the copper separation process, the raw material is passed through the color sorting device again.

[0086] Although not required, it is preferable that the color sorting device sorts in multiple stages, in which case the first stage separates brass from other materials. Brass, also known as yellow brass, is an alloy of copper and zinc. Brass is a reddish yellow color and can be separated into brass and other materials through the color sorting device. Of the raw materials that have gone through the copper sorting process, approximately 48% can be recovered as brass, and approximately 52% as non-brass is sent to the subsequent color sorting device.

[0087] Although not essential, the color sorting device preferably sorts in multiple stages, and in this case, the second stage preferably separates stainless steel from other materials.

[0088] Of the raw materials that have undergone the copper sorting process, approximately 48% can be recovered as brass, approximately 4% as stainless steel, and approximately 48% as residue.

[0089] The selected brass and stainless steel are stored in a designated area outside the color sorter, while the remainder is sent for separation by known processes.

[0090] The various sorted metals are chemically processed at respective smelters to become metal ingots, etc.

[0091] Thus, according to this embodiment, first the substrate is removed by the metal equipment rough dismantling machine, then the iron is removed from the roughly dismantled (not crushed) mass using a magnetic separator, and then the aluminum is removed using an X-ray optical separator. The substrate, iron, and aluminum are all in a roughly dismantled state, not crushed.

[0092] The lump from which the substrate, iron, and aluminum have been extracted is then crushed and granulated by a hammer separation crusher. The iron is then extracted using a magnetic separator, and the stainless steel and plastic are extracted using an electromagnetic induction eddy current composite separator. At this point, most of the copper and brass remain, so they are extracted using a color sorting device. In this way, according to this embodiment, by combining various processes with different methods, it is possible to recover various types of metals from waste. Moreover, by performing the processes in the above-mentioned order, it is possible to perform high-purity sorting with reduced contamination of other metals in subsequent processes.

[0093] In the metal equipment rough dismantling machine, rough dismantling is performed, but at this point, the substrate contained in the raw material is not broken into small pieces. This makes it easy to extract precious metals from the substrate. In the metal equipment rough dismantling machine of this embodiment, a metal twister is arranged on the upper side, and a chain crusher is arranged below the metal twister. As a result, the metal twister first loosely breaks apart the hard metal exterior of the casing, making it possible to remove the substrate from inside the exterior. The raw material from which the exterior has been broken apart falls downward and is hit by the chain crusher. As a result, the substrate and other parts attached to the substrate (such as a part of the exterior) are discharged from the metal equipment rough dismantling machine in a separated state. In this way, it is possible to remove the substrate from the raw material without breaking it into smaller pieces than necessary.

[0094] In addition, a magnetic separator is brought close to the raw materials that have been roughly dismantled through the rough dismantling process (first magnetic separation process) to separate out the iron, then the raw materials are passed through an X-ray AI separator to remove the substrates, and an X-ray optical separator is used to remove the aluminum. This reduces the amount of iron and aluminum that turns into powder and gets mixed in during the processes after the crushing process, making it possible to extract high-purity stainless steel, copper, brass, etc.

[0095] The electromagnetic induction eddy current combined sorting machine is equipped with an upper induction sorting section and a lower eddy current metal sorting section, where stainless steel is sorted from the raw materials in the upper induction sorting section, and the raw materials from which stainless steel has been removed in the lower eddy current metal sorting section are separated into metals including copper and brass, and other non-metals such as plastics. This makes it possible to sort high-purity copper and brass with extremely low amounts of stainless steel and non-metals in the copper sorting process and brass sorting process in the lower section. Moreover, since the induction sorting section is located in the upper section and the eddy current metal sorting section is located in the lower section, the installation space for the equipment can be reduced compared to separating the equipment into an electromagnetic induction sorter and an eddy current sorter.

[0096] It should be noted that within the scope of the concept of the present invention, a person skilled in the art may come up with various modifications and alterations. It is understood that such modifications and alterations fall within the scope of the present invention. For example, even if a person skilled in the art appropriately adds, deletes, or modifies the design of the above-described embodiment, or adds, omits, or modifies the conditions of a process, these modifications and alterations are included in the scope of the present invention as long as they include the gist of the present invention. EXAMPLES

[0097] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these.

[0098] Using the above-mentioned method, 7,200 tons of miscellaneous metals from house demolition were separated into various metals. Figure 5 is a flow chart showing the process.

[0099] As shown in Figure 5, 7,200 tons of miscellaneous metals from house demolition can be separated into 5,238 tons of iron (5,211 tons using the method described in Figure 1, 27 tons using known chemical processes), 606 tons of copper (576 tons using the method described in Figure 1, 30 tons using known chemical processes), 144 tons of brass, 216 tons of aluminum, 144 tons of stainless steel, 180 kg of precious metals (including rare metals), 808 tons of synthetic resin building materials, and 14 tons of residue. As a result, not only can the waste of the 7,200 tons of miscellaneous metals from house demolition that would have been entirely disposed of as industrial waste in the past be reduced to 14 tons (about 0.2%), but about 99.8% can be converted into valuable metals, etc., and precious metals and rare metals can also be recovered. [Explanation of symbols]

[0100] 1 Metal equipment rough dismantling machine 5 Crushing Room 10 Image Recognition Sensor 11 Metal Twister 11a Engagement part 11b Striking section 12 Chain Crusher 13 Motor 14 Rotational Axis 20 Electromagnetic induction eddy current composite separator 21 Induction and Selection Section 211 Conveyor Belt 212 Inductive Sensor 213 High Pressure Valve 214 Image Sensor 22 Eddy current metal sorting section 221 Rotating magnet roller type magnetic separator 222 Conveyor Belt

Claims

1. a rough dismantling process in which the exterior of the raw material is destroyed to separate the exterior from the substrate; a first magnetic separation step carried out after the first magnetic separation step, in which iron is separated using a magnet; an X-ray optical sorting step, which is carried out after this step, to separate out the aluminum; A crushing process is carried out after this process, in which the raw material is crushed into granules; a second magnetic separation step performed after the first step, in which iron is separated using a magnet; A stainless steel sorting process is carried out after the above process, in which stainless steel detected by the electromagnetic induction sensor is blown away with air to separate the stainless steel. This process is followed by a waste plastic removal process in which metals and non-metals are separated using eddy currents and the non-metals are removed. a copper separation step carried out after this step, in which copper is separated from the separated metal by eddy currents; and a brass separation step carried out after this step to separate brass from the copper separating metals.

2. The metal recovery method according to claim 1, The rough dismantling step is a metal recovery method in which the exterior of the discarded equipment, which is the raw material, is crushed, and then the exterior is separated from the substrate attached to the exterior.

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