Method for recovering transition metal or post-transition metal from material composition containing resin and transition metal or post-transition metal

Abstract

To provide novel technical means that enables recovery of a transition metal or a post-transition metal from a material composition including a resin and the transition metal or the post-transition metal.SOLUTION: A method for recovering a transition metal or a post-transition metal from a material composition, the method comprises a step (1) of preparing a material composition containing a resin and a transition metal or a post-transition metal that has been brought into contact with a melt containing an alkali metal compound, and a step (2) of separating the transition metal or the post-transition metal from a mixture resulting from step (1).SELECTED DRAWING: Figure 5A

Description

[Technical Field]

[0001] This patent application claims priority to Japanese Patent Application No. 2024-089450, filed on May 31, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to a method for recovering a transition metal or a post-transition metal from a material composition comprising a resin and the transition metal or a post-transition metal. [Background technology]

[0003] Transition metals and post-transition metals (e.g., noble metals such as copper) have excellent advantages, such as high thermal conductivity, electrical conductivity, ductility, corrosion resistance, beautiful luster, and / or the ability to form alloys with various metals, and are therefore used in a variety of materials (e.g., materials for electronic and electrical products). Furthermore, with the shift to electronic and electric devices, renewable energy, and electric vehicles (EVs) progressing toward achieving carbon neutrality, demand for transition metals and post-transition metals is expected to increase.

[0004] Transition metals or post-transition metals are commonly processed together with various resins. Among these, material compositions containing transition metals or post-transition metals processed together with chlorine-containing resins (e.g., polyvinyl chloride) are widely used, and the amount of waste generated is also increasing. Because the transition metals or post-transition metals contained in the material compositions are highly useful, methods for recovering the transition metals or post-transition metals from the material compositions have been investigated.

[0005] For example, when the material composition is an electric wire, a known method involves physically separating the coating (e.g., chlorine-containing resin) from the copper wire. In the case of small-diameter electric wires, a stripping machine cannot physically separate the copper wire from the coating. Therefore, a process known as nugget processing is sometimes used, in which the copper wire and the coating are separated while being crushed using a shredder, and the mixture of the separated copper wire and the coating is physically sorted based on the differences in their physical properties. However, there are issues with this process, such as the need to separate the copper wire according to the coating and type of electric wire before passing it through the shredder, the difficulty of processing cross-connected electric wires, and / or the difficulty of completely separating the coating from the copper wire, resulting in low purity of the recovered copper. Therefore, methods for recovering transition metals or post-transition metals from the material composition using chemical processing methods have been investigated.

[0006] For example, Patent Document 1 proposes a method for recovering metallic copper by heating waste copper wire coated with a chlorine-containing resin in oil and / or under oxygen-free conditions. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-76121 Summary of the Invention

[0008] An object of the present disclosure is to provide a new technical means for recovering a transition metal or a post-transition metal from a material composition containing a resin and the transition metal or a post-transition metal.

[0009] The present inventors have found that in a method for recovering a transition metal or a post-transition metal from a material composition containing a resin and the transition metal or a post-transition metal, the transition metal or the post-transition metal can be recovered by using a melt containing an alkali metal compound. The present disclosure is based on this finding.

[0010] According to one embodiment of the present disclosure, (1) providing a material composition comprising a resin and a transition metal or post-transition metal in contact with a melt comprising an alkali metal compound; and (2) A step of separating the transition metal or post-transition metal from the mixture obtained in the step (1). a method for recovering a transition metal or post-transition metal from the material composition, comprising: is provided.

[0011] According to the present disclosure, a transition metal or a post-transition metal can be recovered from a material composition containing a resin and the transition metal or a post-transition metal. [Brief explanation of the drawings]

[0012] [Figure 1] The appearance of the test specimen used is shown below. [Figure 2] In Example 1, the appearance and SEM images of the recovered copper wire are shown. [Figure 3A] In Example 1, the amount of chlorine captured in the filtrate was measured. [Figure 3B] In Example 1, the amount of chlorine generated was measured and the results are shown below. [Figure 3C] In Example 2, the amount of chlorine captured in the filtrate was measured. [Figure 3D] In Example 2, the amount of chlorine generated was measured and the results are shown below. [Figure 4A] In Example 1, the results of measuring the amounts of hydrogen and methane generated are shown. [Figure 4B] In Example 2, the results of measuring the amounts of hydrogen and methane generated are shown. [Figure 5A] In Example 3, the appearance of the recovered copper wire and residue is shown. [Figure 5B] In Example 3, the results of measuring the mass of the recovered copper wire and residue (carbonized material) are shown. [Figure 6] In Example 3, the amounts of chloride ions and copper ions dissolved in the filtrate were measured. The results are shown below. [Figure 7A]In Example 3, the amount of chlorine generated was measured and the results are shown below. [Figure 7B] In Example 3, the results of measuring the amounts of hydrogen, methane, carbon monoxide and carbon dioxide generated are shown. [Figure 8] In Example 4, the appearance of the recovered copper wire is shown. [Figure 9A] In Example 4, the results of measuring the amount of chlorine generated and the amount of chlorine captured in the filtrate are shown. [Figure 9B] In Example 4, the results of measuring the amounts of hydrogen, methane, carbon monoxide and carbon dioxide generated are shown. [Figure 10] In Example 5, the appearance of the recovered copper wire and residue is shown. [Figure 11] In Example 5, the results of measuring the amount of chlorine generated and the amount of chlorine captured in the filtrate, as well as the amounts of hydrogen and methane generated are shown. [Figure 12] In Example 6, the appearance of the recovered copper wire is shown. [Figure 13] In Example 7, the appearance of the recovered copper wire is shown. [Figure 14] In Example 8, the appearance of the recovered aluminum is shown. [Figure 15] In Examples 9 and 10 the appearance of the recovered copper is shown. Specific Description of the Invention

[0013] According to one embodiment of the present disclosure, (1) preparing a material composition containing a resin and a transition metal or post-transition metal in contact with a melt containing an alkali metal compound (also referred to as "step (1)" in this disclosure); and (2) A step of separating the transition metal or post-transition metal from the mixture obtained in the step (1) (also referred to as "step (2)" in the present disclosure). a method for recovering a transition metal or post-transition metal from the material composition, comprising: is provided.

[0014] According to one embodiment of the present disclosure, the use of a melt containing an alkali metal compound is advantageous in that it enables partial or substantial decomposition, gasification, or the like of a portion or substantially all of the resin contained in the material composition. Furthermore, according to a preferred embodiment of the present disclosure, it is particularly advantageous in that it can suppress the generation of halogen-containing gases, such as chlorine-containing gases, when the resin contains halogens, such as chlorine. Without being bound by theory, it is believed that the alkali metal compound acts as a decomposition catalyst for the resin. Furthermore, it is quite unexpected that halogen-containing gases, such as chlorine-containing gases, are distributed (e.g., dissolved) in the melt when the resin contains halogens, such as chlorine. Furthermore, according to one embodiment of the present disclosure, the use of a melt containing an alkali metal compound is advantageous in that it can recover transition metals or post-transition metals with high yield and / or high purity. According to a preferred embodiment of the present disclosure, it is particularly advantageous in that it can suppress the generation of carbon monoxide and / or carbon dioxide, which may be generated during the decomposition process of the material composition. The method of the present disclosure is described in detail below.

[0015] [Process (1)] In step (1), a material composition containing a resin and a transition metal or post-transition metal is prepared, and the material composition is in contact with a melt containing an alkali metal compound. In step (1), the melt containing the alkali metal compound and the material composition are in contact. Therefore, in step (1), the material composition may be heated under conditions in which the solid alkali metal compound and the material composition coexist, causing the alkali metal compound to reach its melting point and become a melt, and then the material composition may be contacted (or immersed, as the case may be) with the melt containing the alkali metal compound. Alternatively, the material composition may be immersed in the melt containing the alkali metal compound. The coexistence of the solid alkali metal compound and the material composition can be achieved by separately preparing the solid alkali metal compound (e.g., powder) and the material composition and mixing them (e.g., sprinkling the powder of the alkali metal compound on the material composition). Alternatively, the material composition may be contacted with a solution containing the alkali metal compound (e.g., an aqueous solution containing the alkali metal compound) and the material composition, and the solvent of the solution may be removed by heating or other methods, thereby adhering the alkali metal compound to the surface of the material composition.

[0016] According to one embodiment of the present disclosure, step (1) is a step of preparing the material composition immersed in the melt. According to a preferred embodiment of the present disclosure, step (1) includes a step of immersing the material composition in the melt. Immersing the material composition in the melt is advantageous from the viewpoints of more efficiently decomposing the resin contained in the material composition and / or suppressing contact of the transition metal or post-transition metal with gases such as the atmosphere, thereby further suppressing deterioration (e.g., oxidative deterioration) of the transition metal or post-transition metal, and / or more easily separating the transition metal in step (2) described below.

[0017] The process of immersing or maintaining the material composition in the melt (also referred to as "immersion process" in the present disclosure) may be either a batch process or a continuous process. The batch process is, for example, a process in which a predetermined amount of the melt is charged into a reactor, a predetermined amount of the material composition is added thereto, an immersion process is performed, and the transition metal or post-transition metal is extracted. In the batch process, multiple material compositions may be added to the reactor multiple times. The continuous process is, for example, a process in which the melt is continuously supplied to and discharged from a reactor to circulate, while continuously introducing the material composition into the reactor, performing the immersion process, and extracting the transition metal or post-transition metal.

[0018] According to one embodiment of the present disclosure, the alkali metal compound may be heated to melt it (i.e., to form a melt). Examples of the heating method include convection heating using gas, etc.; radiation heating using infrared rays, far infrared rays, microwaves, etc.; conduction heating such as by contact with a hot plate; and any combination of two or more of these.

[0019] In step (1), stirring may be carried out.

[0020] According to one embodiment of the present disclosure, the heating is radiation heating (preferably microwave heating). In particular, microwave heating is advantageous in that transition metals or post-transition metals can be recovered with lower energy than other heating methods. Known devices and equipment may be used as the device for microwave heating.

[0021] The power for microwave heating is not limited to these, but is, for example, 200 to 2000 W, preferably more than 200 W and not more than 1000 W, more preferably 300 to 800 W, and even more preferably 300 to 600 W. Further investigations by the present inventors have revealed that when 16 g of an alkali metal compound (for example, sodium hydroxide) is used, the alkali metal compound dissolves (i.e., a melt of the alkali metal compound can be obtained) by setting the power to more than 200 W.

[0022] Step (1) may be carried out in a reactor. Examples of the reactor include a silicon carbide vessel, a glass vessel, a quartz vessel, and a stainless steel vessel. According to one embodiment of the present disclosure, when the heating is performed by microwaves, the reactor is preferably made of quartz and / or glass from the viewpoint of more efficiently heating the melt and / or the material composition.

[0023] According to one embodiment of the present disclosure, in step (1), the material composition is heated by contacting the material composition with a melt containing an alkali metal compound. The melt is, for example, a melt of the alkali metal compound. For the avoidance of doubt, the "immersion treatment" in the present disclosure is different from a dissolution treatment method in which the material composition is immersed in an organic solvent (e.g., an alcohol solvent, an ether solvent, a ketone solvent, an ester solvent, or an amide solvent) and heated to decompose and dissolve the resin.

[0024] According to one embodiment of the present disclosure, the temperature of the melt containing the alkali metal compound in step (1) is not particularly limited as long as the object of the present disclosure can be achieved. From the viewpoint of the yield and / or purity of the obtained transition metal or post-transition metal, the temperature of the melt is preferably above 200°C, more preferably above 300°C, and even more preferably above 300°C. Furthermore, from the viewpoint of suppressing deterioration, damage, etc. of the recovered transition metal or post-transition metal, the temperature of the melt is preferably below 800°C, more preferably below 600°C, and even more preferably below 500°C. According to a preferred embodiment of the present disclosure, the temperature of the melt is above 200°C and below 600°C, preferably 250°C to 600°C, and more preferably 300°C to 500°C.

[0025] According to one embodiment of the present disclosure, when microwave heating is used, the temperature of the melt containing the alkali metal compound in step (1) may be greater than 200°C and less than or equal to 500°C, preferably 210 to 400°C, and more preferably 220 to 300°C. Without being bound by theory, microwave heating in step (1) is advantageous in that it heats not only the melt but also the material composition (particularly the transition metal or post-transition metal contained in the material composition), thereby enabling decomposition and / or gasification of the resin at a lower temperature, in a shorter time, and / or more efficiently. Furthermore, since the resin can be decomposed and / or gasified even at a lower temperature, it is advantageous in that it can further suppress deterioration of the transition metal or post-transition metal.

[0026] According to one embodiment of the present disclosure, the resin (preferably, a halogen-containing resin such as a chlorine-containing resin) is decomposed into low molecular weight compounds and dissolved in the melt. According to one embodiment of the present disclosure, it is advantageous in that the decomposition treatment of the resin (preferably, a halogen-containing resin such as a chlorine-containing resin) can be carried out even at the above temperature.

[0027] The contact time between the melt and the material composition in step (1) is appropriately set depending on the heating temperature, the composition of the material composition, and the like. The contact time is preferably 1 minute or more, more preferably 3 minutes or more, and even more preferably 5 minutes or more. If the immersion time is equal to or longer than the lower limit, decomposition and / or gasification of the resin can be promoted. The upper limit of the contact time is not particularly limited, but is, for example, 24 hours or less, preferably 10 hours or less, and more preferably 5 hours or less. According to one embodiment of the present disclosure, the contact time may be 0.1 to 24 hours, preferably 0.5 to 12 hours, and more preferably 1 to 6 hours.

[0028] Step (1) may be carried out under any gas atmosphere. According to one embodiment of the present disclosure, step (1) may be carried out under an air atmosphere or a non-oxidizing gas atmosphere. A non-oxidizing gas atmosphere is an atmosphere that does not contain oxygen gas or an atmosphere that is substantially free of oxygen gas. An atmosphere that is substantially free of oxygen gas does not include an atmosphere to which oxygen gas is intentionally added when heating the material composition, but includes an atmosphere to which oxygen gas is inevitably mixed. Examples of non-oxidizing gases include inert gases such as nitrogen gas and argon gas.

[0029] Step (1) may be carried out under normal pressure, reduced pressure, or increased pressure. According to one embodiment of the present disclosure, step (1) is carried out under normal pressure.

[0030] Since step (1) can be carried out under an atmospheric environment, it is easy to enlarge the reactor that contains the melt, which is advantageous in that it allows the use of a large-sized material composition (e.g., a material composition containing long fibers, large waste materials, or process waste materials) as the processing target.

[0031] <Material composition> In the present disclosure, a "material composition" is defined as comprising a transition metal or a late transition metal and a resin. The material composition may contain at least one of a transition metal or a late transition metal. The material composition may contain only one transition metal, only one late transition metal, or both at least one transition metal and at least one late transition metal. Therefore, according to one embodiment of the present disclosure, the material composition contains at least one metal selected from a transition metal and a late transition metal. According to one embodiment of the present disclosure, the material composition contains at least one transition metal and at least one late transition metal.

[0032] The material composition may be a composite of the transition metal or post-transition metal and the resin, or may be a composite of the transition metal or post-transition metal and the resin. When the material composition is a composite, the material composition may be, for example, a laminate of a layer containing a transition metal or post-transition metal and a layer containing a resin, or a mixture of the transition metal or post-transition metal and the resin. According to one embodiment of the present disclosure, the material composition is a composite ..., in which at least a portion of the transition metal or post-transition metal is coated with the resin. According to one embodiment of the present disclosure, when the material composition is a composite of the transition metal or post-transition metal and the resin, in which at least a portion of the transition metal or post-transition metal is coated with the resin, this is advantageous in that a step of physically separating the coated portion (e.g., peeling) is not necessarily required.

[0033] The material composition may contain other components in addition to the transition metal or post-transition metal and the resin.

[0034] The shape of the material composition is not particularly limited, and examples thereof include a plate, a sheet, a square pipe, a round pipe, an L-shaped cross section, a T-shaped cross section, a C-shaped cross section, an H-shaped cross section, and any other three-dimensional shape.

[0035] The material composition may be waste material from used products, or process waste materials such as scraps and scraps generated in the manufacturing process of intermediate materials or products. It is preferable to use waste material from used products or process waste materials generated in the manufacturing process of intermediate materials or products as the material composition.

[0036] When the material composition is a large intermediate material or product, the material composition may be cut to an appropriate size as needed using a cutter, etc. When cutting the material composition containing long fibers, the material composition may be cut along the longitudinal direction of the long fibers contained in the material composition, so that the long fibers can be recovered in as long a length as possible.

[0037] When the material composition is a product, the entire product may be the material composition, or a part of the product may be the material composition. That is, the target in step (1) may contain the material composition, and may be, for example, a composite of the material composition and another component. Examples of the other component include ceramics.

[0038] Examples of products containing the material composition include piping, displays, electric wires, electronic substrates, electronic elements, candy and pharmaceutical packaging, syringes, etc. Note that the term "electric wire" in this disclosure is not particularly limited as long as it contains a resin and a transition metal or a post-transition metal. Therefore, in this disclosure, the term "electric wire" is intended to encompass not only electrical conductors used to transmit high current electricity, but also those used to transmit low current electricity, such as in communication circuits, and cables. Examples of electric wires include, but are not limited to, electrical wires and communication wires.

[0039] According to one embodiment of the present disclosure, the material composition or a product containing the material composition includes an electric wire such as a copper electric wire (preferably a copper wire coated with a resin, more preferably a copper wire coated with a halogen-containing resin, even more preferably a copper wire coated with a chlorine-containing resin, and even more preferably a copper wire coated with a chlorine-containing resin containing polyvinyl chloride). According to one embodiment of the present disclosure, the material composition or a product containing the material composition includes an electric wire containing a transition metal (preferably an electric wire containing a noble metal, more preferably a copper electric wire).

[0040] According to one embodiment of the present disclosure, when the material composition is used for an electric wire (preferably, an electric wire containing a transition metal, more preferably, an electric wire containing a precious metal such as copper), contacting the material composition with a melt containing an alkali metal compound is advantageous in that it can separate the precious metal without completely decomposing the coating (mainly resin) covering the precious metal. Without being bound by theory, it is believed that when at least a portion of the coating is decomposed, the precious metal is peeled off from the coating, making it possible to separate the precious metal without completely decomposing the coating. This is particularly advantageous compared to other material compositions, such as those for electronic substrates, where it is generally considered difficult to recover the transition metal or post-transition metal unless substantially all of the layers constituting the electronic substrate are decomposed.

[0041] <Transition metals or post-transition metals> The transition metal or post-transition metal is not particularly limited as long as it can achieve the objectives of the present disclosure. According to one embodiment of the present disclosure, the transition metal or post-transition metal is preferably other than a lanthanide or an actinide. Therefore, according to one embodiment of the present disclosure, the transition metal or post-transition metal may be defined as a "transition metal or post-transition metal (excluding a lanthanide or an actinide)." Examples of the transition metal or post-transition metal include: a noble metal selected from the group consisting of copper, silver, gold, platinum, palladium, rhodium, iridium, ruthenium, osmium, and rhenium; scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, yttrium, niobium, molybdenum, technetium, tantalum, tungsten, and rhenium; and a post-transition metal such as aluminum, gallium, indium, thallium, germanium, tin, bismuth, polonium, lead, and zinc. These may be used alone or in any combination of two or more.

[0042] According to one embodiment of the present disclosure, the transition metal or post-transition metal is not a metal compound. The phrase "a transition metal or post-transition metal that is not a metal compound" refers to a molecule in which an atom of the transition metal or post-transition metal is chemically bonded to an atom other than the transition metal or post-transition metal (such as oxygen or nitrogen). Therefore, according to one embodiment of the present disclosure, the transition metal or post-transition metal may be defined as "a transition metal or post-transition metal (excluding metal compounds)." The method of the present disclosure can be advantageously used to recover a transition metal or post-transition metal that is not a metal compound. Without being bound by theory, it is believed that a transition metal or post-transition metal that is not a metal compound is less likely to dissolve in a melt containing the alkali metal compound.

[0043] According to one embodiment of the present disclosure, the transition metal or post-transition metal at least comprises a transition metal or aluminum. According to one embodiment of the present disclosure, the transition metal or post-transition metal at least comprises a transition metal. According to one embodiment of the present disclosure, the transition metal or post-transition metal at least comprises a noble metal or iron. According to one embodiment of the present disclosure, the transition metal or post-transition metal at least comprises a noble metal. According to one embodiment of the present disclosure, the transition metal or post-transition metal at least comprises a noble metal selected from the group consisting of copper (preferably metallic copper), silver (preferably metallic silver), gold (preferably metallic gold), and platinum (preferably metallic platinum). According to one embodiment of the present disclosure, the transition metal or post-transition metal at least comprises copper (preferably metallic copper). The method of the present disclosure can be particularly advantageously used for recovering transition metals (preferably noble metals such as copper).

[0044] The amount of the transition metal or post-transition metal contained in the material composition is not particularly limited as long as the object of the present disclosure can be achieved. The amount of the transition metal or post-transition metal contained in the material composition may be, for example, 1 to 99 parts by mass, preferably 10 to 90 parts by mass, and more preferably 30 to 70 parts by mass, based on 100 parts by mass of the material composition.

[0045] <Resin> The "resin" (also referred to as "resin material" in the present disclosure) is not particularly limited as long as it can be decomposed or the like upon contact with a melt of an alkali metal compound. The resin may be, for example, thermoplastic or thermosetting. The resin may be a natural resin or a synthetic resin (e.g., plastic). Specific examples of the resin include, but are not limited to, acrylic resin, polyethylene resin, polyamide resin, polypropylene resin, polystyrene resin (e.g., α-methylstyrene resin), polycarbonate resin, polyethylene terephthalate resin, polyacrylonitrile resin, silicone resin, polycellulose resin, polyurethane resin, various reinforced resins (e.g., carbon fiber reinforced resin, glass fiber reinforced resin, etc.), and synthetic resins such as halogen-containing resins (e.g., fluorine-containing resin, chlorine-containing resin, bromine-containing resin, iodine-containing resin). The resin may also be a copolymer resin (e.g., acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, acrylonitrile-ethylene-styrene (AES) resin, or acrylonitrile-chlorinated polyethylene-styrene (ACS) resin). The resin may be one type alone or any combination of two or more types.

[0046] According to one embodiment of the present disclosure, the resin includes a synthetic resin.

[0047] According to one embodiment of the present disclosure, the resin contains at least a halogen-containing resin. When the resin contains a halogen-containing resin (preferably a chlorine-containing resin), the method of the present disclosure is particularly advantageous in that it can suppress the generation of halogen-containing gas (preferably a chlorine-containing gas). The halogen-containing resin is not particularly limited as long as it contains a halogen element (e.g., fluorine, chlorine, bromine, iodine) and can be decomposed or otherwise treated by contact with a melt of an alkali metal compound. The halogen-containing resin may contain two or more different halogens. The amount of halogen contained in the halogen-containing resin is not particularly limited as long as the object of the present disclosure can be achieved. Examples of halogen-containing resins include fluorine-containing resins, chlorine-containing resins, bromine-containing resins, and iodine-containing resins, which may be used alone or in any combination of two or more. Examples of fluorine-containing resins include polyvinyl fluoride (PVF), polyvinylidene fluoride, polytrifluoroethylene, polychlorotrifluoroethylene, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and fluorinated ethylene propylene; blends of fluorine-containing resins with other resins, which may be used alone or in any combination of two or more. Examples of chlorine-containing resins include polyvinyl chloride resins, polyvinylidene chloride resins, vinyl chloride or vinylidene chloride copolymers such as vinyl chloride ethylene copolymers and vinyl chloride vinyl acetate copolymers; chlorinated resins such as chlorinated polyethylene, chlorinated rubber, and chlorinated polyethers; and blends of chlorine-containing resins with other resins, which may be used alone or in any combination of two or more. Examples of the bromine-containing resin include brominated polyacrylate resins; blends of bromine-containing resins with other resins, and the like, which may be used alone or in any combination of two or more kinds.

[0048] According to one embodiment of the present disclosure, the resin includes at least a chlorine-containing resin.

[0049] According to one embodiment of the present disclosure, the chlorine-containing resin includes at least polyvinyl chloride.

[0050] The amount of resin contained in the material composition is not particularly limited as long as the object of the present disclosure can be achieved, and may be, for example, 1 to 99 parts by mass, preferably 10 to 90 parts by mass, and more preferably 30 to 70 parts by mass, based on 100 parts by mass of the material composition.

[0051] The mass ratio of the transition metal or post-transition metal to the resin contained in the material composition is not particularly limited as long as the object of the present disclosure can be achieved. The mass ratio of the transition metal or post-transition metal to the resin contained in the material composition (transition element / resin) may be 0.03 to 90, preferably 0.1 to 50, more preferably 0.1 to 10, and even more preferably 0.3 to 3.

[0052] ≪Optional ingredients≫ The material composition may contain optional components other than the transition metal or post-transition metal and the resin, such as antioxidants, heat stabilizers, weathering agents, release agents, lubricants, pigments, dyes, plasticizers, antistatic agents, and flame retardants, which may be used alone or in any combination of two or more.

[0053] <Melt containing alkali metal compounds> The melt containing an alkali metal compound is not particularly limited as long as it contains an alkali metal compound. The amount of the alkali metal compound in the melt is not particularly limited as long as the object of the present disclosure can be achieved. The amount of the alkali metal compound in the melt is, for example, about 80 to 100 mass%, preferably about 85 to 100 mass%, more preferably about 88 to about 99 mass%, and even more preferably about 90 to about 98 mass%, relative to the total mass of the melt. When the amount is less than 100 mass%, at least a portion of the remainder may be an impurity contained in the active pharmaceutical ingredient of the alkali metal compound (e.g., potassium hydroxide).

[0054] The amount of the melt containing the alkali metal compound is, from the viewpoint of ensuring good decomposition of the resin (preferably a halogen-containing resin such as a chlorine-containing resin), for example, 1 part by mass or more, preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, still more preferably 200 parts by mass or more, even more preferably 300 parts by mass or more, still more preferably 500 parts by mass or more, still more preferably 800 parts by mass or more, still more preferably 1000 parts by mass or more, still more preferably 1200 parts by mass or more, and still more preferably 1500 parts by mass or more, per 100 parts by mass of the material composition. While there is no particular upper limit on the amount of the alkali metal compound used, from the viewpoint of cost, the amount of the alkali metal compound used is, for example, 10,000 parts by mass or less, preferably 5,000 parts by mass or less, more preferably 4,000 parts by mass or less, and still more preferably 3,000 parts by mass or less, per 100 parts by mass of the material composition.

[0055] The viscosity of the melt is not particularly limited as long as the object of the present disclosure can be achieved. The viscosity of the melt may be, for example, 50 mPa·s or less, preferably 20 mPa·s or less, and more preferably 10 mPa·s or less. The viscosity of the melt may be adjusted to the above range by adjusting the type and amount of the alkali metal compound described below. Setting the viscosity of the melt to the above range is advantageous in that it can reduce the amount of alkali metal compound adhering to or remaining on the transition metal or post-transition metal after separation from the melt. Note that the viscosity of the melt referred to in the present disclosure refers to the viscosity measured at a given temperature under the following conditions: Equipment: DV-1, manufactured by Brookfield Pressure: atmospheric pressure

[0056] <Alkali metal compounds> The "alkali metal compound" in the present disclosure is not particularly limited as long as it is a compound of an alkali metal. Examples of the alkali metal compound include, but are not limited to, compounds of alkali metals such as lithium, sodium, potassium, rubidium, and cesium (e.g., hydroxides, alcoholates, phenolates, inorganic acid salts (e.g., phosphates, carbonates, sulfates, and nitrates), and organic acid salts of alkali metals), which may be used alone or in any combination of two or more.

[0057] Among these, from the viewpoint of enabling the decomposition of a resin (preferably a halogen-containing resin such as a chlorine-containing resin) to proceed satisfactorily at low temperatures (for example, 600°C or less, preferably 500°C or less, more preferably 400°C or less), alkali metal hydroxides are preferred, and those containing at least one selected from the group consisting of sodium hydroxide and potassium hydroxide are more preferred, with potassium hydroxide being particularly preferred.

[0058] To further lower the temperature of a melt containing an alkali metal compound, for example, a method of lowering the freezing point (melting point) of the alkali metal compound by using a combination of multiple alkali metal compounds can be used. Alternatively, to further lower the temperature of a melt containing an alkali metal compound, for example, the alkali metal compound may be allowed to coexist with other substances (for example, impurities contained in the alkali metal compound).

[0059] When potassium hydroxide is approximately 100% pure, its melting point is approximately 360°C. However, in the presence of other substances (e.g., alkali metal compounds other than potassium hydroxide, impurities, etc.), the melting point can drop to 300°C or lower (preferably 280°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower). Note that the term "impurity" used in this context refers to an unintentional substance that may be contained in a potassium hydroxide drug substance (e.g., a reagent). Therefore, substances that may be intentionally allowed to coexist with potassium hydroxide (e.g., sodium hydroxide, as described below) are not considered "impurities." When potassium hydroxide contains impurities, the purity of the potassium hydroxide is less than 100% (i.e., the remainder is impurities). In one embodiment of the present disclosure, potassium hydroxide is preferably less than 100% pure (i.e., contains impurities), more preferably 85% or more but less than 100%, and even more preferably 85% or more but less than 99% pure. Potassium hydroxide with a purity of less than 100% is available from, for example, Fujifilm Wako Pure Chemical Industries, Ltd., Sigma-Aldrich, etc.

[0060] Examples of the impurities include, but are not limited to, potassium salts other than potassium hydroxide (e.g., chlorides such as potassium carbonate and potassium chloride, phosphates such as potassium phosphate, and silicates such as potassium silicate), metals such as sodium, magnesium, calcium, zinc, aluminum, iron, copper, nickel, chromium, manganese, and rubidium, and salts of these metals (e.g., hydroxides, chlorides, carbonates, phosphates, etc.).

[0061] The melting point of potassium hydroxide can also be lowered in the presence of sodium hydroxide. For example, potassium hydroxide with a purity of about 100% has a melting point of about 360°C when used alone, as described above. However, in the presence of sodium hydroxide with a purity of about 100%, the melting point can be lowered to about 300°C or lower (preferably about 280°C or lower, more preferably about 250°C or lower, and even more preferably about 200°C or lower). The melting point when potassium hydroxide and sodium hydroxide coexist can vary depending on their ratio (e.g., mass ratio, molar ratio, etc.). For such melting points, reference may be made to known literature, information, etc. For example, referring to https: / / www.metallab.net / chemsoc / alloys.php?id=19, when the molar ratio of potassium hydroxide to sodium hydroxide is about 4:1 to about 1:19 (i.e., the mass ratio of potassium hydroxide to sodium hydroxide is about 1:14 to about 7:1), a melt can be formed even at about 300°C or below (preferably, about 300°C or below and about 170°C or above). Alternatively, a person skilled in the art can experimentally measure the melting point at a desired ratio, for example, by referring to a known melting point measurement method (e.g., visual observation, thermal analysis, etc.). When sodium hydroxide and sodium hydroxide coexist, the melting point can be further lowered by the additional presence of the above-mentioned impurities.

[0062] According to one embodiment of the present disclosure, the amount of potassium hydroxide contained in the alkali metal compound is 45% by mass or more, preferably greater than 70% by mass, more preferably 72.5% by mass or more, and even more preferably 85% by mass or more, based on the total mass of the alkali metal compound. Setting the amount of potassium hydroxide in the alkali metal compound within this range is advantageous from the viewpoint of accelerating the decomposition rate of resins and other materials derived from the material composition. Setting the amount of potassium hydroxide in the alkali metal compound within this range is also advantageous from the viewpoint of more efficient recovery of fuel gases such as hydrogen gas ( FIG. 9B ). Setting the amount of potassium hydroxide in the alkali metal compound within this range is also advantageous from the viewpoint of recovery of transition metals or post-transition metals at lower temperatures. Furthermore, from the viewpoint of the viscosity of the melt, by setting the amount of potassium hydroxide in the alkali metal compound within the above range, a melt having a low viscosity (for example, a viscosity of 50 mPa·s or less, preferably 10 mPa·s or less) can be obtained even at a low temperature (for example, 400°C or less, preferably 300°C or less) (this is advantageous in that, for example, the amount of alkali metal compound adhering to or remaining on the transition metal or post-transition metal after separation from the melt can be reduced).

[0063] When the alkali metal compound contains potassium hydroxide and sodium hydroxide, the ratio of potassium hydroxide to sodium hydroxide contained in the alkali metal compound (in other words, the ratio of potassium hydroxide to sodium hydroxide in the melt) is, in terms of mass ratio, for example, 3:1 to 1:3.5, preferably 3:1 to 1:3, more preferably 3:1 to 1:1.5, and more preferably 3:1 to 1:1. Furthermore, in the alkali metal compound, the amount of sodium hydroxide per part by mass of potassium hydroxide is, for example, 0.3 parts by mass or more and 3.5 parts by mass or less, preferably 0.3 parts by mass or more and less than 3.5 parts by mass, more preferably 0.3 parts by mass or more and 1.2 parts by mass or less, and even more preferably 0.3 parts by mass or more and 1 part by mass or less. In one embodiment of the present disclosure, the molar ratio of potassium hydroxide to sodium hydroxide in the alkali metal compound (in other words, the ratio of potassium hydroxide to sodium hydroxide in the melt) is, for example, 3:1 to 1:5, preferably 2.5:1 to 1:4, more preferably 2.2:1 to 1:2, and even more preferably 2:1 to 1:1.

[0064] The amount of alkali metal compound used is, from the viewpoint of ensuring good decomposition of the resin (preferably a halogen-containing resin such as a chlorine-containing resin), for example, 1 part by mass or more, preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, still more preferably 200 parts by mass or more, still more preferably 300 parts by mass or more, still more preferably 500 parts by mass or more, still more preferably 800 parts by mass or more, still more preferably 1000 parts by mass or more, still more preferably 1200 parts by mass or more, and still more preferably 1500 parts by mass or more, per 100 parts by mass of the material composition. There is no particular upper limit to the amount of alkali metal compound used, but from the viewpoint of cost, the amount of alkali metal compound used is, for example, 10,000 parts by mass or less, preferably 5,000 parts by mass or less, more preferably 4,000 parts by mass or less, and still more preferably 3,000 parts by mass or less, per 100 parts by mass of the material composition. When a plurality of the material compositions are charged into the reactor multiple times, it is desirable to adjust the amount of the material composition charged each time so that the amount of alkali metal compound used each time is the above-mentioned amount.

[0065] The amount of the melt containing the alkali metal compound in the reactor into which the material composition is introduced is not particularly limited as long as the decomposition of the resin (preferably a halogen-containing resin such as a chlorine-containing resin) proceeds. From the viewpoint of ensuring good decomposition of the resin (preferably a halogen-containing resin such as a chlorine-containing resin), the amount of the melt containing the alkali metal compound in the reactor into which the material composition is introduced is, for example, 1 part by mass or more, preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, even more preferably 200 parts by mass or more, even more preferably 300 parts by mass or more, even more preferably 500 parts by mass or more, even more preferably 800 parts by mass or more, even more preferably 1000 parts by mass or more, even more preferably 1200 parts by mass or more, and even more preferably 1500 parts by mass or more, relative to 100 parts by mass of the material composition introduced. The amount of the melt containing the alkali metal compound in the reactor is not particularly limited, but is, for example, 10,000 parts by mass or less, preferably 5,000 parts by mass or less, relative to 100 parts by mass of the material composition introduced. In the case of a continuous system, the rate at which the melt is fed into the reactor and the rate at which the melt is discharged from the reactor are not particularly limited.

[0066] [Process (2)] In step (2), the transition metal or post-transition metal is separated from the mixture obtained in step (1) (i.e., a mixture containing at least an alkali metal-containing melt and a transition metal or post-transition metal). The separation method is not particularly limited, but examples include a method in which the transition metal or post-transition metal is extracted from the melt and, if necessary, washed with a washing liquid. The melt after separation can be reused as is or after further treatment. According to one embodiment of the present disclosure, the alkali metal compound can be recovered and reused repeatedly, which is advantageous in that the running costs of the method of the present disclosure are lower than those of conventional techniques.

[0067] Examples of cleaning methods include immersion cleaning, ultrasonic cleaning, spray cleaning, shower cleaning, and jet cleaning, and two or more of these methods may be combined. In the case of immersion cleaning and ultrasonic cleaning, the transition metal or post-transition metal is immersed in a cleaning solution, and after stirring as necessary, the transition metal or post-transition metal can be separated from the cleaning solution. Examples of such separation methods include filtration, sedimentation, and centrifugation.

[0068] In the case of immersion washing, although not limited thereto, for example, the material composition placed in a mesh container (e.g., wire mesh) may be brought into contact with a melt of an alkali metal compound, and after a desired time has elapsed, the mesh container containing the transition metal or post-transition metal may be removed from the melt and immersed in a washing liquid, etc. Alternatively, the material composition and a solid alkali metal compound may be placed in a furnace such as a kiln, and the furnace may be heated to bring the material composition into contact with a melt of an alkali metal compound (e.g., immersed or kept immersed), and after a desired time has elapsed, the kiln may be rotated, tilted, etc. to recover the transition metal or post-transition metal, which may then be immersed in a washing liquid, etc.

[0069] Examples of cleaning solutions include water and organic solvents. Examples of organic solvents include alcohol solvents such as methanol, ethanol, propanol, benzyl alcohol, and ethylene glycol monomethyl ether; ether solvents such as dipropyl ether, diisopropyl ether, and dibutyl ether; ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as ethyl acetate, propyl acetate, and γ-butyrolactone; and amide solvents such as N-methylformamide, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpyrrolidone. These may be used alone or in any combination of two or more. A mixture of water and an organic solvent may also be used as the cleaning solution. A cleaning solution containing at least water is preferred, and a cleaning solution containing 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more of water based on the total mass of the cleaning solution is more preferred. Acidic aqueous solutions such as aqueous solutions of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid may also be used as the cleaning solution. The pH of the cleaning solution can be adjusted as appropriate by those skilled in the art.

[0070] The amount of the cleaning solution used is not particularly limited, and can be adjusted appropriately by a person skilled in the art depending on the amount and composition of the mixture obtained in step (1) above, the type of cleaning solution used, etc. The amount of the cleaning solution used may be, for example, 0.1 to 1000 parts by mass, preferably 1 to 300 parts by mass, and more preferably 5 to 100 parts by mass, based on 1 part by mass of the mixture obtained in step (1) above (total mass).

[0071] Without being bound by theory, for example, when a solvent containing at least water is used as the cleaning solution, alkali metal compounds and resin-derived components (preferably halogen products (e.g., halogen-containing gases such as chlorine-containing gases) derived from halogen-containing resins such as chlorine-containing resins) are thought to be distributed in the cleaning solution. Therefore, for example, when the resin contains a halogen-containing resin, the cleaning solution from which the transition metal or post-transition metal has been separated can be heated, neutralized, or the like to remove halogen-containing gases (e.g., chlorine-containing gases), and then the solvent can be removed (e.g., by heating), thereby recovering and reusing the alkali metal compounds. Furthermore, for example, using a solvent containing at least water as the cleaning solution allows alkali metal compounds and the like to be distributed in the cleaning solution, which is advantageous from the viewpoint of industrially separating the transition metal or post-transition metal from the mixture obtained in step (1) using simple equipment (e.g., without necessarily requiring a device such as a centrifuge). According to one embodiment of the present disclosure, step (2) does not include a centrifugation step.

[0072] Furthermore, without being bound by theory, for example, when a solvent containing at least water (preferably water) is used as the cleaning liquid, mixing the mixture obtained in step (1) above (i.e., a melt containing an alkali metal and a mixture containing at least a transition metal or a post-transition metal) with the cleaning liquid can yield an alkaline solution (e.g., pH 7 to 14). Therefore, when the material composition used contains a transition metal (preferably a noble metal) that is thought to be poorly soluble in a basic solution and a post-transition metal (preferably an amphoteric metal such as aluminum, tin, zinc, or lead) that is thought to be soluble in a basic solution, it may be possible to recover the transition metal as a residue and the post-transition metal in the basic solution (i.e., as a filtrate). Therefore, when the material composition contains a transition metal (preferably a noble metal, more preferably copper) and a post-transition metal (preferably an amphoteric metal, more preferably aluminum), using a solvent containing at least water (preferably water) as the cleaning solution is particularly advantageous from the viewpoint that it not only makes it possible to distribute the alkali metal compound and resin-derived components into the cleaning solution, but also makes it possible to separate a residue in which the presence of a post-transition metal is suppressed (i.e., a residue containing a transition metal at a high purity).

[0073] According to one embodiment of the present disclosure, the step (2) includes a step of mixing the mixture obtained in the step (1) with a solvent containing at least water (preferably water), and separating a residue containing a transition metal or a post-transition metal (preferably a transition metal, more preferably a noble metal such as copper).

[0074] According to one embodiment of the present disclosure, the step (2) includes a step of immersing the mixture obtained in the step (1) in a solvent containing at least water (preferably water) and separating a residue containing a transition metal or a post-transition metal (preferably a transition metal, more preferably a noble metal such as copper).

[0075] According to one embodiment of the present disclosure, the step (2) includes a step of separating a residue from the mixture obtained in the step (1), and a step of immersing the obtained residue in a solvent containing at least water (preferably water) to separate a residue containing a transition metal or a post-transition metal (preferably a transition metal, more preferably a noble metal such as copper).

[0076] The conditions for washing are not particularly limited. The temperature of the washing liquid may be room temperature, or may be a temperature at which the washing liquid remains liquid, for example, it may be heated to increase the amount of dissolved components derived from the chlorine-containing resin and alkali metal compounds. For example, when a washing liquid containing at least water is used, the temperature of the washing liquid is preferably 5 to 90°C, more preferably 10 to 80°C. The washing time is also not particularly limited.

[0077] According to one embodiment of the present disclosure, when a water-containing cleaning liquid (preferably water) is used as the cleaning liquid, a step of adjusting the pH of the cleaning liquid may be further carried out. Without being bound by theory, mixing the mixture obtained in step (1) (i.e., a melt containing an alkali metal and a mixture containing at least a transition metal or a post-transition metal) with a water-containing cleaning liquid (preferably water) may result in an alkaline solution (e.g., pH 7 to 14). Therefore, if necessary, a pH adjuster or the like may be added to the cleaning liquid to adjust the pH of the cleaning liquid. Examples of such pH adjusters include organic acids or inorganic acids (e.g., hydrochloric acid, nitric acid, acetic acid, etc.), which may be used alone or in any combination of two or more. Those skilled in the art can appropriately adjust the amount of pH adjuster used depending on the amount and composition of the mixture obtained in step (1) (e.g., the type of alkali metal compound used), the type of pH adjuster used, and the like.

[0078] The above-described cleaning method can easily remove components derived from resins (preferably halogen-containing resins such as chlorine-containing resins) and / or alkali metal compounds that may adhere to transition metals or post-transition metals. Furthermore, according to a preferred embodiment of the present disclosure, the above-described cleaning method (particularly a cleaning method using a cleaning liquid containing water) can easily remove post-transition metals that may be contained in the material composition.

[0079] After washing the transition metal or post-transition metal, the transition metal or post-transition metal may be dried using a dryer such as an oven. Furthermore, if the residue obtained after drying contains not only the transition metal or post-transition metal but also carbides (e.g., products obtained by decomposition of a resin derived from the material composition), further separation (e.g., separation by sieving) may be carried out as necessary.

[0080] [Process (3)] According to one embodiment of the present disclosure, the method may include (3) a step of recovering the gasified gas (also referred to as "step (3)" in the present disclosure). Without being bound by theory, contact between the melt of the alkali metal compound and the material composition may cause decomposition and / or gasification of the resin (preferably a halogen-containing resin such as a chlorine-containing resin) in the material composition, thereby generating gas. Therefore, including step (3) in the method is advantageous in that useful gas (e.g., fuel gas such as hydrogen or methane) generated by the method can be recovered.

[0081] The method for recovering the gas is not particularly limited, but examples thereof include recovery using any solvent, recovery using known devices and equipment (for example, gas packs), etc.

[0082] The step (3) may be carried out simultaneously with the step (1), the step (2), or any other step, or may be carried out before or after each of these steps.

[0083] [Method for Producing Transition Metals or Post-Transition Metals] According to another embodiment of the present disclosure, there is provided a method for producing a transition metal or a post-transition metal, comprising the step of separating the transition metal or the post-transition metal from a material composition comprising a resin (preferably a halogen-containing resin, such as a chlorine-containing resin) and the transition metal or the post-transition metal using a method for recovering the transition metal or the post-transition metal from the material composition.

[0084] [Melted composition or solidified product thereof] According to another embodiment of the present disclosure, there is provided a melt composition for recovering a transition metal or a post-transition metal, or a solidified product thereof, which comprises a melt containing an alkali metal compound, a transition metal or a post-transition metal, and a component derived from a resin (preferably a halogen-containing resin such as a chlorine-containing resin) dissolved in the melt. The melt composition may be obtained, for example, by immersing the material composition described above in a melt containing an alkali metal compound. The transition metal or the post-transition metal can be recovered by separating it from the melt composition. The melt composition may be cooled to form a solidified product.

[0085] In the melt composition, the amount of the melt containing the alkali metal compound is, for example, 1 part by mass or more, preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, even more preferably 200 parts by mass or more, even more preferably 300 parts by mass or more, even more preferably 500 parts by mass or more, even more preferably 800 parts by mass or more, even more preferably 1000 parts by mass or more, even more preferably 1200 parts by mass or more, and even more preferably 1500 parts by mass or more, relative to 100 parts by mass of the material composition. There is no particular upper limit on the amount of the alkali metal compound used, but from the viewpoint of cost, the amount of the alkali metal compound used is, for example, 10,000 parts by mass or less, preferably 5,000 parts by mass or less, more preferably 4,000 parts by mass or less, and even more preferably 3,000 parts by mass or less, relative to 100 parts by mass of the material composition.

[0086] In the melt composition, the amount of the alkali metal compound is, for example, about 80 to 100% by mass, preferably about 85 to 100% by mass, more preferably about 88 to 99% by mass, and even more preferably about 90 to 98% by mass, relative to the total mass of the melt containing the alkali metal compound. When the amount is less than 100% by mass, at least a portion of the remainder may be an impurity contained in the active pharmaceutical ingredient of the alkali metal compound (e.g., potassium hydroxide).

[0087] For example, by adding a solvent (e.g., a solvent containing water) to the melt composition or a solidified product thereof and heating, neutralizing, etc., components derived from the resin (preferably a halogen-containing resin such as a chlorine-containing resin) can be decomposed and / or gasified and removed. This results in a melt composition with few impurities (e.g., resin, resin-derived components). The melt composition may be cooled to form a solidified product. The obtained melt composition or a solidified product thereof can be used as a melt containing an alkali metal compound in the method of the present disclosure.

[0088] The definitions of each term, preferred embodiments, etc. are as described above in this specification.

[0089] [Gas recovery composition] According to another embodiment of the present disclosure, there is provided a composition for gas recovery obtained by separating a transition metal or a post-transition metal from the melt composition or a solidified product thereof. The composition for gas recovery may be in a molten state or a solid state. For example, the melt composition after separation of the transition metal or the post-transition metal may be cooled to obtain a solidified composition for gas recovery.

[0090] By adding a solvent (e.g., a solvent containing water) to the gas recovery composition and heating it at an appropriate temperature, the resin-derived components contained in the gas recovery composition are decomposed and / or gasified, allowing the recovery of, for example, a fuel gas or a halogen-containing gas (e.g., a chlorine-containing gas). The fuel gas in the present disclosure is not particularly limited as long as it is a gas that can be used as a fuel, and examples thereof include hydrogen and methane. The "halogen-containing gas" in the present disclosure is not particularly limited as long as it is a gas that contains a halogen atom, and examples thereof include fluorine-containing gases such as fluorine gas and hydrogen fluoride; chlorine-containing gases such as hydrogen chloride and chlorine gas; bromine-containing gases such as bromine gas and hydrogen bromide; and iodine-containing gases such as hydrogen iodide. The halogen-containing gas may also be a gas containing two or more different halogen elements in its molecule.

[0091] The heating temperature of the composition for gas recovery during gas recovery is preferably 50°C or higher, more preferably 70°C or higher, even more preferably 90°C or higher, and particularly preferably 100°C or higher.

[0092] The heating time of the composition for gas recovery during gas recovery is appropriately set depending on the heating temperature. The heating time is preferably 10 minutes or more, more preferably 20 minutes or more, and even more preferably 30 minutes or more. The upper limit of the heating time is not particularly limited, but is preferably 10 hours or less, more preferably 5 hours or less, and even more preferably 2 hours or less.

[0093] After recovering the gas from the composition for gas recovery, the remaining solvent can be removed by heating or the like to recover the alkali metal compound. The recovered alkali metal compound can be used as a melt containing the alkali metal compound in the method of the present disclosure.

[0094] According to a preferred embodiment of the present disclosure, the composition for gas recovery is a composition for fuel gas recovery. According to a preferred embodiment of the present disclosure, the composition for gas recovery is a composition for halogen-containing gas recovery (preferably a composition for chlorine-containing gas recovery).

[0095] The definitions of each term, preferred embodiments, etc. are as described above in this specification.

[0096] [Method for suppressing generation of halogen-containing gases] According to another embodiment of the present disclosure, there is provided a method for suppressing the generation of halogen-containing gases during the separation of a transition metal or a post-transition metal from a material composition containing a halogen-containing resin and the transition metal or a post-transition metal, the method comprising contacting the material composition with a melt of an alkali metal compound.

[0097] According to one embodiment of the present disclosure, the halogen-containing resin includes a chlorine-containing resin, and the halogen-containing gas includes a chlorine-containing gas.

[0098] According to a preferred embodiment of the present disclosure, the chlorine-containing gas contains at least hydrogen chloride.

[0099] According to a preferred embodiment of the present disclosure, the method suppresses the generation of carbon monoxide and / or carbon dioxide.

[0100] The definitions of each term, preferred embodiments, etc. are as described above in this specification.

[0101] The present disclosure encompasses the following. [1] (1) providing a material composition comprising a resin and a transition metal or post-transition metal in contact with a melt containing an alkali metal compound; and (2) A step of separating the transition metal or post-transition metal from the mixture obtained in the step (1). a method for recovering a transition metal or post-transition metal from the material composition, comprising: [2] The method according to [1], wherein the step (1) is a step of preparing the material composition immersed in the melt. [3] The method according to [1] or [2], wherein the step (1) includes a step of immersing the material composition in the melt. [4] The method according to any one of [1] to [3], wherein the temperature of the melt in step (1) is higher than 200°C. [5] The method according to any one of [1] to [4], wherein the temperature of the melt in step (1) is 600°C or lower. [6] The method according to any one of [1] to [5], wherein the melt in step (1) is heated by microwaves. [7] The method according to any one of [1] to [6], wherein the alkali metal compound comprises a hydroxide of an alkali metal. [8] The method according to any one of [1] to [7], wherein the alkali metal compound comprises potassium hydroxide or sodium hydroxide. [9] The method according to any one of [1] to [8], wherein the alkali metal compound comprises potassium hydroxide.

[10] The method according to any one of [1] to [9], wherein the material composition is a transition metal or a post-transition metal, at least part of which is coated with a resin.

[11] The method according to any one of [1] to

[10] , wherein the transition metal or post-transition metal is a noble metal.

[12] The method according to any one of [1] to

[11] , wherein the transition metal or post-transition metal is copper.

[13] The method according to any one of [1] to

[12] , wherein the resin comprises a halogen-containing resin.

[14] The method according to any one of [1] to

[13] , wherein the resin comprises a chlorine-containing resin.

[15] The method according to

[14] , wherein the chlorine-containing resin contains at least polyvinyl chloride.

[16] (3) Recovering the gasified gas. The method according to any one of [1] to

[15] , further comprising:

[17] A step of separating a transition metal or a post-transition metal from a material composition containing a resin and a transition metal or a post-transition metal by using the method according to any one of [1] to

[16] . 1. A method for producing a transition metal or a post-transition metal, comprising:

[18] A melt composition for recovering a transition metal or a post-transition metal, or a solidified product thereof, comprising a melt containing an alkali metal compound, a transition metal or a post-transition metal, and a component derived from a resin dissolved in the melt.

[19] A composition for gas recovery obtained by separating a transition metal or a post-transition metal from the melt composition according to

[18] or a solidified product thereof.

[20] A method for suppressing the generation of halogen-containing gases during separation of a transition metal or a post-transition metal from a material composition containing a halogen-containing resin and the transition metal or a post-transition metal, the method comprising contacting the material composition with a melt of an alkali metal compound.

[0102] The present disclosure also encompasses the following:

[21] (1) providing a material composition comprising a resin and a transition metal or post-transition metal in contact with a melt containing an alkali metal compound; and (2) A step of separating the transition metal or post-transition metal from the mixture obtained in the step (1). a method for recovering a transition metal or post-transition metal from the material composition, comprising:

[22] The method according to

[21] , wherein the step (1) is a step of preparing the material composition immersed in the melt.

[23] The method according to

[22] , wherein the step (1) includes a step of immersing the material composition in the melt.

[24] The method according to any one of

[21] to

[23] , wherein the temperature of the melt in step (1) is higher than 200°C.

[25] The method according to any one of

[21] to

[24] , wherein the temperature of the melt in step (1) is 600°C or lower.

[26] The method according to any one of

[21] to

[25] , wherein the melt in step (1) is heated by microwaves.

[27] The method according to any one of

[21] to

[26] , wherein the alkali metal compound comprises a hydroxide of an alkali metal.

[28] The method according to any one of

[21] to

[27] , wherein the alkali metal compound comprises potassium hydroxide or sodium hydroxide.

[29] The method according to any one of

[21] to

[28] , wherein the alkali metal compound comprises potassium hydroxide.

[30] The method according to any one of

[21] to

[29] , wherein the amount of potassium hydroxide contained in the alkali metal compound is 72.5 mass % or more based on the total mass of the alkali metal compound.

[31] The method according to any one of

[21] to

[30] , wherein the material composition is a transition metal or a post-transition metal at least partially coated with a resin.

[32] The method according to any one of

[21] to

[31] , wherein the material composition comprises an electric wire.

[33] The method according to any one of

[21] to

[32] , wherein the transition metal or post-transition metal is a noble metal.

[34] The method according to any one of

[21] to

[33] , wherein the transition metal or post-transition metal is copper.

[35] The method according to any one of

[21] to

[34] , wherein the resin comprises a halogen-containing resin.

[36] The method according to any one of

[21] to

[35] , wherein the resin comprises a chlorine-containing resin.

[37] The method according to

[36] , wherein the chlorine-containing resin contains at least polyvinyl chloride.

[38] The method according to any one of

[21] to

[37] , wherein the step (2) comprises mixing the mixture obtained in the step (1) with a solvent containing at least water, and separating a residue containing a transition metal or a post-transition metal.

[39] (3) Recovering the gasified gas. The method according to any one of

[21] to

[38] , further comprising:

[40] A step of separating a transition metal or a post-transition metal from a material composition containing a resin and a transition metal or a post-transition metal by using the method according to any one of

[21] to

[39] . 1. A method for producing a transition metal or a post-transition metal, comprising:

[41] A melt composition for recovering a transition metal or a post-transition metal, or a solidified product thereof, comprising a melt containing an alkali metal compound, a transition metal or a post-transition metal, and a component derived from a resin dissolved in the melt.

[42] A composition for gas recovery obtained by separating a transition metal or a post-transition metal from the melt composition according to

[41] or a solidified product thereof.

[43] A method for suppressing the generation of halogen-containing gases during separation of a transition metal or a post-transition metal from a material composition containing a halogen-containing resin and the transition metal or a post-transition metal, the method comprising contacting the material composition with a melt of an alkali metal compound. [Example]

[0103] The method of the present disclosure will be described in more detail below using examples. However, the following examples are not intended to limit the method of the present disclosure in any way. Unless otherwise specified, percentages and ratios described herein are by mass. Furthermore, unless otherwise specified, units and measurement methods described herein are in accordance with the provisions of the Japanese Industrial Standards (JIS).

[0104] [Test piece] (Test piece 1) A portion of a waste wiring harness (copper wire coated with a composition containing polyvinyl chloride) was shredded and used as test piece 1 (Figure 1). The composition of test piece 1 was as shown in Table 1. [Table 1]

[0105] (Test piece 2) A portion of a scrap wire harness (copper wire coated with chlorine-containing resin) was shredded and used as test piece 2 (Figure 1). The copper (copper wire) content of test piece 2 was 62.3% based on the total mass of test piece 2.

[0106] (Test piece 3) A portion of a scrap wire harness (copper wire coated with a chlorine-containing resin) was shredded to prepare test piece 3 (Fig. 1). The copper content of test piece 3 was 40.5 mass% based on the total mass of test piece 3. The composition of the remainder of test piece 3 (i.e., the chlorine-containing resin) was as shown in Table 2. [Table 2]

[0107] (Test piece 4) A copper wire in a cross-connected state coated with a chlorine-containing resin was used as test piece 4 (Fig. 1).

[0108] (Test piece 5) A part of a waste wire harness (copper wire coated with chlorine-containing resin) was cut into small pieces to prepare a test piece 5 (FIG. 1).

[0109] (Test piece 6) A package containing aluminum (3-10 mass% aluminum foil, 90-97 mass% film, 0.4665 g) was used as test piece 6 (Fig. 1).

[0110] (Test piece 7) A mixture of aluminum (Al, 0.87 g), copper (Cu, 2.96 g), and polyethylene (PE, 0.75 g) was used as specimen 7 (Figure 1).

[0111] [Production of salts containing alkali metal compounds] Potassium hydroxide (KOH, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., purity 85% or higher) and sodium hydroxide (NaOH, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., purity 97% or higher) were mixed in a mass ratio of 3:1, 1:1, or 1:3 (i.e., about 0.3 parts by mass, about 1 part by mass, or about 3 parts by mass of sodium hydroxide per 1 part by mass of potassium hydroxide), heated at 400°C for 1 hour, and then allowed to cool, to obtain a mixed salt. Similarly, potassium hydroxide alone or sodium hydroxide alone was heated at 400°C for 1 hour and then allowed to cool, to produce a salt mixture. Assuming that the purities of the potassium hydroxide and sodium hydroxide used are 85% and 97%, respectively, the converted mass ratios for 3:1, 1:1, and 1:3 are approximately 2.6:1, approximately 1:1.2, and approximately 1:3.4, respectively (i.e., approximately 0.4 parts by mass, approximately 1.2 parts by mass, and approximately 3.4 parts by mass of sodium hydroxide per 1 part by mass of potassium hydroxide). The amount of potassium hydroxide contained in the mixed salt is, based on the total mass of the mixed salt, When the mass ratios are 3:1, 1:1, and 1:3, the values ​​are 72.2 mass%, 45.6 mass%, and 23.2 mass%, respectively (calculated based on the converted masses assuming that the purities of the potassium hydroxide and sodium hydroxide used are 85% and 97%, respectively). The mass ratio of potassium hydroxide to sodium hydroxide described below indicates the ratio before conversion.

[0112] [Example 1: Recovering copper wire 1] A 0-4 M solution (5 mL) of the potassium hydroxide (prepared by heating potassium hydroxide at 400 °C for 1 hour and then allowing it to cool) and test piece 1 (3 g) were placed in a reactor, and test piece 1 was immersed in the solution. The reactor was heated to 140 °C over 15 minutes and then maintained at 140 °C for 15 minutes to evaporate the solvent (water) from the solution, and 0-20 mmol of potassium hydroxide was brought into contact with test piece 1 (0 M, 1 M, 2 M, and 4 M correspond to 0 mmol, 5 mmol, 10 mmol, and 20 mmol, respectively). The reactor was then capped and maintained at 140 °C. Nitrogen gas was then passed through the reactor at 200 mL / min for 15 minutes to purge the atmosphere inside the reactor. The nitrogen gas flow rate was changed to 20 mL / min, and the temperature was raised to 500 °C in a nitrogen atmosphere over 45 minutes. After the temperature was raised, the residue was allowed to cool naturally for 30 minutes. The halogen gas generated during the heating process was collected with 200 mL of 0.1 M sodium hydroxide solution, and non-condensable gases (i.e., gases not collected with the 0.1 M sodium hydroxide solution) (H2, CH4) were collected using a gas pack (Tedlar bag, manufactured by DuPont). The residue after heating was removed from the reactor, added to 100 mL of distilled water, and stirred at 40°C for 1 hour. After stirring, the mixture was filtered to separate the filtrate and residue. The residue was thoroughly dried and then sieved using a 2 mm sieve to separate the carbide and copper wire. The appearance of the recovered copper wire and an image taken with a scanning electron microscope (SEM) (JSM-6510A, manufactured by JEOL Ltd.) are shown in Figure 2. The pH of the filtrate was measured using a pH meter (LAQUA, F-72). The chlorine concentration in the filtrate was measured using a chloride ion meter (Kasahara Chemical Industries, CL-10Z). The amount of chlorine captured (corresponding to the amount of chlorine-containing gas captured) was calculated using the following formula. The results are shown in Figure 3A.

[0113]

number

[0114] The chlorine concentration in the sodium hydroxide solution in which the halogen gas was collected was measured using a chloride ion meter (CL-10Z, KRK), and the amount of chlorine generated (corresponding to the amount of chlorine-containing gas generated) was calculated using the following formula. The results are shown in Figure 3B.

[0115]

number

[0116] The non-condensable gases were collected in the gas pack and analyzed using a gas chromatograph (GC-8A, Shimadzu). The results are shown in Figure 4A.

[0117] [Example 2: Copper wire collection 2] The copper wire was recovered in the same manner as in Example 1, except that a 0-4 M solution of sodium hydroxide (NaOH, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., purity 97% or higher) was used instead of the 0-4 M solution of potassium hydroxide. The amount of potassium hydroxide coated on test piece 1 was 0-20 mmol, the same as in Example 1. The results are shown in Figures 2, 3C, 3D, and 4B.

[0118] [Example 3: Recovering copper wire 3] The salt containing the alkali metal compound (mixed salt) produced above was used to recover the copper wire from the test piece 2 by the following method. 60 g of the above mixed salt (KOH:NaOH = 1:0, 3:1, 1:1, 1:3, 0:1) and test piece 2 (10 g) placed in a Φ40 mesh stainless steel container were placed in a cylindrical reactor. A stainless steel weight was also placed on top of test piece 2 in the Φ40 mesh stainless steel container so that test piece 2 was fully immersed in the melt (molten salt). Nitrogen gas was passed through the reactor at 100 mL / min for 30 minutes to replace the atmosphere with nitrogen. The temperature was then raised to 600°C in 60 minutes under a nitrogen atmosphere. After the temperature was raised, the residue was allowed to cool naturally for 30 minutes. The heated residue was removed from the reactor, placed in 100 mL of distilled water, and stirred at 40°C for 1 hour using a stirrer. After stirring, the mixture was filtered to separate the filtrate and residue. The residue was thoroughly dried and then sieved using a 2 mm sieve to separate the charcoal and copper wire, and their masses were measured. The appearance of the recovered charcoal and copper wire are shown in Figure 5A. The masses of the recovered charcoal and copper wire are also shown in Figure 5B. Furthermore, the chlorine concentration of the obtained filtrate was measured using a chloride ion meter, and the copper ion concentration was measured using an atomic absorption spectrophotometer (apparatus: A Analyst 200, PerkinElmer). The amounts of chlorine and copper dissolved in the filtrate were calculated using the following formula. The results are shown in Figure 6.

[0119]

number

[0120] In addition, using the same method as in Example 1, the halogen gas generated during the heating process was collected with 0.1 M sodium hydroxide solution (200 mL), and the non-condensable gases (H, CH, CO, CO) were collected with a gas pack. The amounts of chlorine, hydrogen, methane, carbon monoxide, and carbon dioxide generated were evaluated. The results are shown in Figures 7A and 7B.

[0121] [Example 4: Recovering copper wire 4] The salt containing the alkali metal compound (mixed salt) produced above was used to recover copper wire from test piece 3 by the following method. 60 g of the above mixed salt (KOH:NaOH = 1:0, 3:1, 1:1, 1:3, 0:1) and test piece 3 (10 g) placed in a Φ40 mesh stainless steel container were placed in a cylindrical reactor. A stainless steel weight was also placed on top of test piece 3 in the Φ40 mesh stainless steel container so that test piece 3 was fully immersed in the molten salt. Nitrogen gas was passed through the reactor at 100 mL / min for 30 minutes to replace the atmosphere with nitrogen. The reactor was then heated at 200-600°C for 1 hour under a nitrogen atmosphere (heating time: 20 minutes). The residue was then allowed to cool naturally. The resulting residue was added to distilled water, stirred, and filtered to obtain a filtrate and a residue. The resulting residue was dried and sieved to recover the charcoal and copper wire, and their masses were measured. The appearance of the recovered charcoal and copper wire is shown in Figure 8. Using the same method as in Example 1, halogen gas generated during the heating process was collected using 0.1 M sodium hydroxide solution (200 mL), and non-condensable gases (H2, CH4, CO, CO2) were collected using a gas pack. The amounts of hydrogen, methane, carbon monoxide, and carbon dioxide generated were evaluated using the same methods as in Examples 1 and 3. The chlorine concentrations collected in the 0.1 M sodium hydroxide solution and in the filtrate obtained above (i.e., the chlorine captured in the mixed salt) were analyzed using an ion chromatograph (IC-2010, TOSOH), and the amount of chlorine was calculated using the following formula. The results are shown in Figures 9A and 9B.

[0122]

number

[0123] [Example 5: Recovering copper wire 5] The same procedure as in Example 4 was carried out except that the above mixed salt (KOH:NaOH=1:0) was used, the heating time was 1 to 3 hours, and the heating temperature was 300°C, and the copper wire was recovered from Test Piece 3. The results are shown in Figures 10 and 11.

[0124] [Example 6: Recovering copper wire 6] The same procedure as in Example 4 was carried out, except that test piece 4 and the above mixed salt (KOH:NaOH=1:0) were used, the heating time was 1 hour, and the heating temperature was 400° C., and the copper wire was recovered from test piece 4. The results are shown in FIG. 12 and Tables 3 and 4.

[0125] [Table 3]

[0126] [Table 4]

[0127] [Example 7: Recovering copper wire 6] The potassium hydroxide (10 g) produced above and test piece 5 (1 g) were placed in a quartz Erlenmeyer flask and microwave-heated (μReactor EX, manufactured by Shikoku Keisoku Kogyo) for 10 minutes at 500 W, and the copper wire was recovered from test piece 5. The results are shown in Figure 13. Furthermore, when the gas generated during heating was collected in the same manner as in Example 1, approximately 100 mL of gas (hydrogen: 3.7%, methane: 25%, nitrogen etc.: balance) was collected.

[0128] [Example 8: Aluminum recovery] The sodium hydroxide (20 g) prepared above and test piece 6 (0.4665 g) were placed in a stainless steel crucible and heated to 400°C for 1 hour (heat-up time: 30 minutes). Test piece 6 was fully immersed in the molten salt. The residue was then allowed to cool naturally, and concentrated nitric acid (60%, 20 mL) was added to the cooled residue to neutralize it. The neutralized residue was washed with distilled water (100 mL), and the aluminum was recovered. The results are shown in Figure 14.

[0129] [Example 9: Recovery of copper from a mixture containing copper, aluminum, and resin 1] The potassium hydroxide (10 g) prepared above and test piece 7 (aluminum: 0.87 g, copper: 2.96 g, and polyethylene: 0.75 g) were placed in a stainless steel crucible and heated to 300°C for 1 hour (heat-up time: 30 minutes). At this time, test piece 7 was fully immersed in the molten salt. The residue was then allowed to cool naturally. The resulting residue was added to distilled water (200 mL), stirred for 30 minutes, and filtered to obtain a filtrate and a residue. The resulting residue was dried, and copper was recovered. However, almost no aluminum was recovered from the residue. The results are shown in Figure 15(A).

[0130] [Example 10: Recovery of copper from a mixture of copper, aluminum and resin 2] The same procedure as in Example 9 was carried out, except that sodium hydroxide (10 g) was used instead of potassium hydroxide, and copper was recovered. On the other hand, almost no aluminum was recovered in the residue. The results are shown in Figure 15(B).

[0131] [Reference Example 1: Recovery of copper from a mixture of copper and aluminum 1] The potassium hydroxide (10 g) prepared above and a mixture of aluminum (0.87 g) and copper (2.96 g) were placed in a stainless steel crucible and heated at 400°C for 1 hour. The aluminum and copper were fully immersed in the molten salt. The residue was then allowed to cool naturally. The resulting residue was added to distilled water (200 mL), stirred for 30 minutes, and filtered to obtain a filtrate and a residue. Approximately 2.96 g of copper was recovered from the residue, but almost no aluminum was recovered from the residue.

[0132] [Reference Example 2: Recovery of copper from a mixture of copper and aluminum 2] The same procedure was carried out as in Reference Example 1, except that nitric acid (1 mol / L, 200 mL) was used instead of distilled water. As a result, about 2.96 g of copper and about 0.27 g of aluminum were recovered from the residue.

[0133] The results of Examples 1 to 7 indicate that by using an alkali metal compound, it was possible to recover a transition metal or a late transition metal (preferably a transition metal, more preferably a noble metal such as copper) from a material composition containing a resin (e.g., a halogen-containing resin such as a chlorine-containing resin) and a transition metal or a late transition metal. Furthermore, the results of Example 8 indicate that by using an alkali metal compound, it was possible to recover a late transition metal (preferably aluminum) from a material composition containing a resin and a late transition metal (FIG. 14). The results of Example 1 and others suggest that by bringing the melt of an alkali metal compound into contact with the material composition, it is possible to decompose the resin (e.g., a halogen-containing resin such as a chlorine-containing resin) in the material composition, thereby enabling the recovery of a transition metal or a late transition metal. In Examples 1 and 2, it is believed that the resin (e.g., halogen-containing resin such as chlorine-containing resin) was decomposed depending on the amount of potassium hydroxide or sodium hydroxide (Figure 2). In particular, when the amount of potassium hydroxide or sodium hydroxide was 10 mmol or more, it is believed that the resin (e.g., halogen-containing resin such as chlorine-containing resin) was almost completely decomposed (Figures 2, 3A, and 3C). Furthermore, the recovered copper wire not only had a glossy finish (especially when the amount was 20 mmol), but also had no noticeable damage or scratches on its surface (Figure 2). In Example 3, regardless of the mass ratio of the salt containing the alkali metal compound, a shiny copper wire could be recovered (FIG. 5A). Furthermore, since only a small amount of copper ions was eluted into the filtrate (i.e., the aqueous solution in which the salt of the alkali metal compound was dissolved), the method of the present disclosure is advantageous in that it can recover transition elements (especially noble metals such as copper) from the material composition with a high yield (FIG. 6). In Example 4, copper could be recovered when treated at above 300°C (preferably 400°C or higher, more preferably 500°C or higher) for 1 hour (FIG. 8). In Example 5, copper could be recovered by treating at 300°C for more than 1 hour (preferably 2 hours or longer) (FIG. 10). Therefore, it is believed that the method of the present disclosure can recover transition elements (particularly noble metals such as copper) from the material composition by appropriately adjusting the temperature and time when the alkali metal compound is brought into contact with the material composition. In Example 6, copper was able to be recovered even from Test Piece 4 (FIG. 12). Therefore, the method of the present disclosure is considered to be advantageous in that it can recover transition metals or post-transition metals even from the above-mentioned material composition in a mixed state.

[0134] The results of Examples 1 to 7 indicate that when a resin contains a halogen (e.g., chlorine), the use of a salt containing an alkali metal compound is advantageous in that it can suppress the generation of a halogen-containing gas (e.g., a chlorine-containing gas) (preferably, little or no halogen-containing gas, such as a chlorine-containing gas, is generated) (FIGS. 3A to 3D, 7A, 9A, and 11). The results of Example 4 indicate that the amount of chlorine generated when no salt containing an alkali metal compound was used (no addition) was comparable to the amount of chlorine captured in the filtrate (i.e., the solution containing the salt containing an alkali metal compound) when the salt containing an alkali metal compound was used (particularly at 300°C or higher) (FIG. 9A). Without being bound by theory, it is believed that the method of the present disclosure can suppress the generation of a halogen-containing gas (e.g., a chlorine-containing gas) when the resin in the material composition contains a halogen-containing resin because the molten alkali metal compound captures the halogen-containing gas (e.g., a chlorine-containing gas) generated during the decomposition of the halogen-containing resin (e.g., a chlorine-containing resin). The method of the present disclosure is also considered to be particularly advantageous in that the use of an alkali metal compound can also suppress the generation of carbon monoxide and / or carbon dioxide (preferably, little or no carbon monoxide and / or carbon dioxide is generated) (FIGS. 7B and 9B). Furthermore, the method of the present disclosure is also considered to be advantageous in that the use of an alkali metal compound makes it possible to recover fuel gases such as hydrogen and methane (FIGS. 7B and 9B).

[0135] The results of Example 7 suggest that the method of the present disclosure was able to recover transition metals or late-transition metals from the material composition, even when microwave heating was used. Without being bound by theory, microwave heating, compared to other heating methods, can heat not only the alkali metal compound but also the material composition (particularly the transition metal or late-transition metal in the material composition), which is believed to enable efficient decomposition of resins (e.g., halogen-containing resins such as chlorine-containing resins) even with short heating periods. Furthermore, the ease with which alkali metal compounds absorb microwaves is believed to contribute to the efficient decomposition of resins (e.g., halogen-containing resins such as chlorine-containing resins) even with short heating periods. These points are believed to be advantageous in terms of enabling recovery of transition metals or late-transition metals from the material composition with less energy than other heating methods.

[0136] The results of Examples 9 and 10, as well as Reference Examples 1 and 2, suggest that when a transition metal (preferably a noble metal, more preferably copper) and a late-transition metal (preferably an amphoteric metal, more preferably aluminum) are present together, the transition metal can be preferentially recovered from the residue obtained by the reaction with an alkali metal compound by mixing the residue with water ( FIG. 15 ). Without being bound by theory, it is believed that the residue obtained by the reaction with an alkali metal compound also contains the alkali metal compound, and adding water to the residue would result in a basic solution. Therefore, it is believed that the late-transition metal (preferably an amphoteric metal such as aluminum, zinc, lead, or tin, more preferably aluminum) is ionized, resulting in the preferential recovery of the transition metal (preferably a noble metal, more preferably copper) from the residue. This is consistent with the fact that aluminum was also recovered from the residue when an acid such as nitric acid was used instead of water in Reference Example 2 (i.e., the pH of the resulting solution shifted to the acidic side).

[0137] When recovering copper from an electric wire containing a precious metal such as copper (e.g., a copper wire coated with a resin (e.g., a copper electric wire)), the presence of a late transition metal (preferably, an amphoteric metal such as aluminum, zinc, lead, or tin, more preferably aluminum) can be problematic. Conventional methods require the recovery of a precious metal such as copper and a late transition metal (preferably, an amphoteric metal such as aluminum, zinc, lead, or tin, more preferably aluminum), followed by the separation of the precious metal such as copper. On the other hand, according to one embodiment of the present disclosure, a simple method of adding water to a residue obtained by a reaction with an alkali metal compound is particularly advantageous in that it allows the precious metal (preferably, copper) to be preferentially recovered from the residue while removing (preferably, dissolving in the filtrate) the late transition metal (preferably, an amphoteric metal such as aluminum, zinc, lead, or tin, more preferably aluminum). According to one embodiment of the present disclosure, the electric wire is a precious metal electric wire, preferably a copper electric wire.

Claims

1. (1) providing a material composition comprising a resin and a transition metal or post-transition metal in contact with a melt comprising an alkali metal compound; and (2) A step of separating the transition metal or post-transition metal from the mixture obtained in the step (1). a method for recovering a transition metal or post-transition metal from said material composition, comprising:

2. The method of claim 1 , wherein the step (1) is a step of preparing the material composition immersed in the melt.

3. The method of claim 2 , wherein step (1) comprises immersing the material composition in the melt.

4. 2. The method of claim 1, wherein the temperature of the melt in step (1) is greater than 200°C.

5. 2. The method according to claim 1, wherein the temperature of the melt in step (1) is 600°C or less.

6. The method of claim 1 , wherein the melt in step (1) is heated by microwaves.

7. The method of claim 1 , wherein the alkali metal compound comprises an alkali metal hydroxide.

8. The method of claim 1 , wherein the alkali metal compound comprises potassium hydroxide or sodium hydroxide.

9. The method of claim 1 , wherein the alkali metal compound comprises potassium hydroxide.

10. 10. The method according to claim 9, wherein the amount of potassium hydroxide contained in the alkali metal compound is 72.5% by mass or more based on the total mass of the alkali metal compound.

11. The method of claim 1 , wherein the material composition is a transition metal or post-transition metal at least partially coated with a resin.

12. The method of claim 1 , wherein the material composition comprises an electrical wire.

13. The method of claim 1 , wherein the transition metal or post-transition metal is a noble metal.

14. The method of claim 1 , wherein the transition or post-transition metal is copper.

15. The method of claim 1 , wherein the resin comprises a halogen-containing resin.

16. The method of claim 1 , wherein the resin comprises a chlorine-containing resin.

17. 17. The method of claim 16, wherein the chlorine-containing resin comprises at least polyvinyl chloride.

18. 2. The method according to claim 1, wherein the step (2) comprises mixing the mixture obtained in the step (1) with a solvent containing at least water, and separating a residue containing a transition metal or a post-transition metal.

19. (3) A process for recovering the gasified gas The method of claim 1 further comprising:

20. Separating a transition metal or a post-transition metal from a material composition comprising a resin and a transition metal or a post-transition metal using the method of any one of claims 1 to 19.

1. A method for producing a transition metal or a post-transition metal, comprising:

21. A melt composition for recovering a transition metal or a post-transition metal, or a solidified product thereof, comprising a melt containing an alkali metal compound, a transition metal or a post-transition metal, and a component derived from a resin dissolved in the melt.

22. A composition for gas recovery, obtained by separating a transition metal or a post-transition metal from the melt composition according to claim 21 or a solidified product thereof.

23. A method for suppressing the generation of halogen-containing gases during the separation of a transition metal or a post-transition metal from a material composition containing a halogen-containing resin and the transition metal or a post-transition metal, the method comprising contacting the material composition with a melt of an alkali metal compound.

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