Method for recovering noble metals and liquid composition for adsorption

Abstract

A method for recovering a noble metal includes a step of recovering a noble metal by bringing a liquid composition containing the noble metal into contact with an adsorbent material to adsorb the noble metal in the liquid composition to the adsorbent material. The liquid composition further contains water and a substance derived from an oxidizing agent. The amount of water in the liquid composition is 85 mass% or more relative to the entire liquid composition. An adsorption liquid composition used in the method for recovering a noble metal contains water, a substance derived from an oxidizing agent, and a noble metal. The amount of water is 85 mass% or more relative to the entire adsorption liquid composition.

Description

Technical Field

[0001] This disclosure relates to a method for recovering precious metals. More specifically, this disclosure relates to a method for recovering precious metals using an adsorbent material and an adsorption liquid composition for use in this recovery method. Background Technology

[0002] In recent years, many electrical / electronic devices, such as portable phones, have been used and then discarded. These devices utilize various metals, including precious and rare metals. Therefore, discarded electrical / electronic equipment has attracted attention as a "city mine" for extracting precious metals. In particular, gold (Au) is used extensively in the bonding wires connecting the electrodes of IC chips to the lead frame. Therefore, a technology for efficiently recovering gold from this city mine is needed.

[0003] To recover precious metals from obsolete equipment such as those found in urban mines, the precious metals must first be dissolved using a metal dissolving solution. In recent years, "organic aqua regia," containing an organic solvent and copper halides, has been known as a solvent for dissolving gold. In organic aqua regia, copper halides, acting as an oxidizing agent, facilitate the dissolution of gold. A method has been proposed to recover the gold from the solution after dissolving the gold contained in obsolete electrical / electronic equipment into this organic aqua regia. Furthermore, "etching solutions," composed of an organic solvent and halogens as elemental substances, are known for etching semiconductors and other materials containing precious metals. In these etching solutions, iodine, acting as an oxidizing agent, facilitates the dissolution of gold.

[0004] For example, Japanese Patent No. 6196662 (Patent Document 1) discloses a method for recovering gold, which includes: a step of dissolving gold in a solvent system containing copper halide and an aprotic polar solvent; and a step of adding a reducing agent to the solvent system containing gold to precipitate the precious metal. Japanese Patent Application Publication No. 2-310326 (Patent Document 2) discloses a technique in which, after impregnating a porous granular resin with dibutylcarbitol or methyl isobutyl ketone as an organic solvent, a hydrochloric acid solution containing gold is passed through the porous granular resin layer in a liquid state, selectively extracting gold into the dibutylcarbitol or methyl isobutyl ketone. Japanese Patent Application Publication No. 2002-194450 (Patent Document 3) discloses a method in which platinum group precious metals are selectively adsorbed from an organic solvent solution using an adsorbent material with nicotinamide as the active ingredient. Japanese Patent Application Publication No. 2004-211142 (Patent Document 4) discloses an iodine-based etching solution containing an organic solvent compatible with water.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 6196662

[0008] Patent Document 2: Japanese Patent Application Publication No. 2-310326

[0009] Patent Document 3: Japanese Patent Application Publication No. 2002-194450

[0010] Patent Document 4: Japanese Patent Application Publication No. 2004-211142 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] In Patent Document 1, a solvent system containing copper halides is used to dissolve gold. Therefore, other metals (copper) may be mixed in during gold recovery. Furthermore, Patent Document 1 does not offer any idea of ​​using adsorbent materials to recover gold dissolved in organic solvent systems. In the technology disclosed in Patent Document 2, a re-extraction process using dilute acid is required to recover gold extracted by the metal extraction material, which is time-consuming and labor-intensive. The active ingredient in Patent Document 3, nicotinamide, is itself dissolved in organic solvents, thus requiring it to be supported on insoluble materials such as activated carbon. Furthermore, while nicotinamide exhibits excellent selectivity for platinum group metals, it cannot be applied to gold recovery. Patent Document 4 does not mention the recovery of dissolved precious metals.

[0013] The purpose of this disclosure is to provide a method for recovering precious metals, which enables the efficient adsorption of dissolved precious metals onto an adsorbent material for recovery. Another purpose of this disclosure is to provide an adsorption liquid composition comprising dissolved precious metals, which achieves high recovery efficiency using an adsorbent material.

[0014] Solution for solving the problem

[0015] The method for recovering precious metals disclosed herein includes the step of recovering precious metals by contacting a liquid composition containing precious metals with an adsorbent material, thereby adsorbing the precious metals in the liquid composition onto the adsorbent material. The liquid composition also contains water and a substance derived from an oxidant. The amount of water in the liquid composition relative to the total liquid composition is 85% by mass or more.

[0016] The disclosed liquid composition for adsorption is used in the above-mentioned method for recovering precious metals. The liquid composition for adsorption comprises water, a substance derived from an oxidant, and the precious metal. The amount of water relative to the total liquid composition for adsorption is 85% by mass or more.

[0017] The method for manufacturing the above-described liquid composition for adsorption includes the step of dissolving a noble metal in a metal solution containing water and an oxidant to obtain the liquid composition for adsorption. The amount of water in the liquid composition for adsorption is 85% by mass or more relative to the total liquid composition.

[0018] The method for manufacturing the above-described liquid composition for adsorption may include the step of adding water to a precious metal-containing liquid containing a substance derived from an oxidant and a precious metal to obtain the liquid composition for adsorption. The amount of water in the liquid composition for adsorption is 85% by mass or more relative to the total liquid composition.

[0019] Invention Effects

[0020] According to the precious metal recovery method disclosed herein, dissolved precious metals can be efficiently adsorbed onto an adsorbent material for recovery. The precious metals contained in the liquid composition for adsorption disclosed herein exhibit a high adsorption rate onto the adsorbent material. This liquid composition for adsorption minimizes the use of environmentally unfriendly organic solvents and can be easily manufactured without the use of inorganic acids. Detailed Implementation

[0021] The following is a detailed description of an example of a preferred embodiment. The various components and combinations thereof in each embodiment are merely examples, and appropriate additions, omissions, substitutions, and other modifications can be made to the components without departing from the spirit of this disclosure. This disclosure is not limited to the embodiments but only to the claims. Furthermore, the various solutions disclosed in this specification can also be combined with any other features disclosed in this specification.

[0022] The numerical ranges of the various elements disclosed in this specification can be arbitrarily combined with the numerical ranges of other elements. For example, the limitation on the numerical range of the acetyl substitution degree of the cellulose resin can be combined with the limitation on the numerical range of the molecular weight. Furthermore, the numerical ranges of the various elements disclosed in this specification can be set as ranges formed by arbitrarily combining their upper and lower limits.

[0023] It should be noted that in this specification, "X~Y" indicating a range means "above X and below Y", "ppm" means "mass ppm", and "%" means "mass % (wt.%)". In addition, "mass %" refers to the so-called weight percentage, not the mass concentration. Furthermore, "X' and / or Y'" has the same meaning as "at least one selected from the group consisting of X' and Y'", which means all of "[1] only X', [2] only Y', [3] both X' and Y'"[1]~[3]. In this specification, unless otherwise noted, the test temperature is always room temperature (20℃±5℃).

[0024] (Methods for recycling precious metals)

[0025] This disclosure relates to a technique for recovering precious metals from a liquid composition containing dissolved precious metals using an adsorbent material. The present inventors discovered that the water content in the liquid composition containing the precious metal has a significant impact on the adsorption efficiency of the precious metal on the adsorbent material, thus completing the technique of this disclosure.

[0026] That is, the precious metal recovery method of this disclosure includes the step of recovering precious metals by contacting a liquid composition containing precious metals with an adsorbent material, thereby adsorbing the precious metals in the liquid composition onto the adsorbent material. The liquid composition also contains water and a substance derived from an oxidant. In this recovery method, the amount of water in the liquid composition is 85% by mass or more relative to the total liquid composition. In the precious metal recovery method of this disclosure, the amount of water contained in the liquid composition is 85% by mass or more relative to the total liquid composition, thereby promoting the adsorption of precious metals onto the adsorbent material. According to the precious metal recovery method of this disclosure, precious metals can be efficiently recovered by a simple method such as adding an adsorbent material to a liquid composition containing dissolved precious metals.

[0027] (Liquid composition for adsorption)

[0028] The liquid composition for adsorption disclosed herein refers to the liquid composition used in the aforementioned method for recovering precious metals, specifically the liquid composition at the point in time that it comes into contact with the adsorbent material. In this specification, unless otherwise specified, the terms "liquid composition" and "liquid composition for adsorption" are used with the same meaning.

[0029] The disclosed liquid composition for adsorption comprises dissolved noble metal, water, and a substance derived from an oxidant. The amount of water contained in the liquid composition for adsorption is 85% by mass or more relative to the total liquid composition. By contacting the liquid composition for adsorption, which contains 85% by mass of water relative to the total liquid composition, with an adsorbent material, the noble metal in the liquid composition for adsorption is adsorbed by the adsorbent material.

[0030] From the perspective of improving the adsorption rate of precious metals, the amount of water in the liquid composition can be more than 85% by mass and less than 100% by mass relative to the overall liquid composition, and can be 88% to 99% by mass, 90% to 98% by mass, 92% to 97% by mass, or 94% to 96% by mass.

[0031] From the viewpoint of improving the adsorption rate of precious metals, this precious metal recovery method may further include a step of adjusting the amount of water in the liquid composition to 85% or more by mass of the total liquid composition before contacting it with the adsorbent material. For example, by adding water after dissolving the precious metal in the metal solution described later, the amount of water in the liquid composition can be adjusted to 85% or more by mass.

[0032] In other words, a method for recovering precious metals according to one embodiment of the present disclosure includes the following steps: (1) dissolving the precious metal in a metal solution to obtain a composition comprising a metal solution and dissolved gold; (2) adding water to the composition to obtain a liquid composition comprising water in an amount of 85% by mass or more; and (3) recovering the precious metal by contacting the liquid composition with an adsorbent material to adsorb the dissolved precious metal onto the adsorbent material.

[0033] In another embodiment, the precious metal recovery method disclosed herein may include the following steps: (1) dissolving the precious metal in a metal solution to obtain a composition comprising a metal solution and dissolved gold; (2) adding water to the composition to obtain a liquid composition comprising water in an amount of 85% by mass or more; (3) contacting the liquid composition with an adsorbent to adsorb the dissolved precious metal onto the adsorbent to obtain a precious metal-containing adsorbent; and (4) recovering the precious metal from the precious metal-containing adsorbent by separating the precious metal-containing adsorbent from the liquid composition.

[0034] Here, "precious metals" refers to gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh), ruthenium (Ru), and osmium (Os). That is, the precious metal recovery method disclosed herein can target one or more of the elements selected from the group consisting of gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh), ruthenium (Ru), and osmium (Os). By appropriately selecting the adsorbent material described later, the precious metals targeted for recovery can be selectively recovered.

[0035] Preferably, the precious metal recovery method of this disclosure targets gold (Au). That is, the liquid composition of this disclosure may contain dissolved gold, water, and substances derived from an oxidizing agent. The amount of water in the liquid composition relative to the total liquid composition is 85% by mass or more. The gold recovery method is also included within the scope of this disclosure, and the gold recovery method includes the step of recovering gold by contacting the liquid composition with an adsorbent material, thereby adsorbing the gold in the liquid composition onto the adsorbent material.

[0036] The concentration of precious metals in the liquid composition is not particularly limited. For example, relative to the whole liquid composition, the concentration of precious metals can be 1 ppm to 2000 ppm, 1 ppm to 1000 ppm, 1 ppm to 500 ppm, 1 ppm to 200 ppm, 10 ppm to 2000 ppm, 10 ppm to 1000 ppm, 10 ppm to 500 ppm, 10 ppm to 200 ppm, 20 ppm to 2000 ppm, 20 ppm to 1000 ppm, 20 ppm to 500 ppm, or 20 ppm to 200 ppm.

[0037] (Substances derived from oxidizing agents)

[0038] In this specification, "substances derived from oxidizing agents" refers to substances produced by the deterioration or alteration of the oxidizing agent. In this disclosure, substances derived from oxidizing agents in the liquid composition may be substances derived from the oxidizing agent in a metal solution used to dissolve precious metals, or substances generated during the process of dissolving precious metals in a metal solution containing an oxidizing agent, which undergoes deterioration or alteration. It should be noted that, within the scope of the effects achieved by this disclosure, the liquid composition may also contain the oxidizing agent itself.

[0039] For example, oxidants that generate substances derived from oxidants can include, for instance, halogen molecules such as iodine molecules (I2), bromine molecules (Br2), and chlorine molecules (Cl2) (X2, X = I, Br, Cl, etc.). In other words, the substance derived from an oxidant in the liquid composition can be one or more selected from the group consisting of substances derived from iodine molecules (I2), substances derived from bromine molecules (Br2), and substances derived from chlorine molecules (Cl2), preferably substances derived from iodine molecules (I2) and / or substances derived from chlorine molecules (Cl2), and more preferably substances derived from iodine molecules (I2).

[0040] If substances derived from the oxidant in the liquid composition are adsorbed by the adsorbent material, they may sometimes hinder the adsorption of precious metals that are to be recovered. From the viewpoint of improving the adsorption rate of precious metals, the content of substances derived from the oxidant in the liquid composition relative to the overall liquid composition can be 0.01% to 20% by mass, 0.1% to 18% by mass, 0.5% to 15% by mass, or 1.0% to 10% by mass.

[0041] (Other additives)

[0042] When a liquid composition contains a substance derived from a halogen molecule (X2, X = I, Br, Cl, etc.) as an oxidizing agent, the liquid composition may further contain a substance derived from a halide. Preferably, the liquid composition contains a substance derived from a halide, wherein the halide comprises a halogen of the same kind as the halogen molecule. Preferably, the liquid composition contains a substance derived from an iodine molecule (I2) and / or a substance derived from a chlorine molecule (Cl2) as an oxidizing agent, and further contains a substance derived from a halide comprising a halogen of the same kind as the oxidizing agent (i.e., iodine compounds and / or chlorine compounds). Examples of such halides include alkali metal halides, alkaline earth metal halides, and ammonium halides. It should be noted that in this specification, "ammonium" refers to ammonium (NH4) + ) and organic ammonium (quaternary ammonium, NR4) + R = hydrocarbon group).

[0043] For example, the liquid composition may contain substances derived from iodine molecules (I2) as oxidants, and substances derived from iodine compounds. In other words, the oxidant-derived substance in the liquid composition may be a substance derived from iodine molecules (I2), and the liquid composition may also contain a substance derived from iodine compounds. The iodine compound is preferably selected from at least one of the group consisting of alkali metal iodides, alkaline earth metal iodides, and ammonium iodides. Examples of alkali metal iodides include lithium iodide (LiI), potassium iodide (KI), and sodium iodide (NaI). Examples of alkaline earth metal iodides include calcium iodide (CaI2), magnesium iodide (MgI2), barium iodide (BaI2), and strontium iodide (SrI2). Examples of ammonium iodides include ammonium iodide and tetrabutylammonium iodide.

[0044] Furthermore, the liquid composition may also contain substances derived from chlorine molecules (Cl2) as oxidants, and substances derived from chlorine compounds. Preferably, the chloride is selected from at least one of the group consisting of alkali metal chlorides, alkaline earth metal chlorides, and ammonium chlorides. Examples of alkali metal chlorides include lithium chloride (LiCl), potassium chloride (KCl), and sodium chloride (NaCl). Examples of alkaline earth metal chlorides include calcium chloride (CaCl2), magnesium chloride (MgCl2), barium chloride (BaCl2), and strontium chloride (SrCl2). Examples of ammonium chlorides include ammonium chloride and tetrabutylammonium chloride. The liquid composition may contain substances derived from iodine molecules (I2) and chlorine molecules (Cl2), as well as substances derived from iodine compounds and substances derived from chlorine compounds.

[0045] When the liquid composition contains a substance derived from a halide, the content of the halide-derived substance relative to the total liquid composition can be 0.01% to 20% by mass, 0.1% to 18% by mass, 1.0% to 15% by mass, or 5.0% to 10% by mass. In liquid compositions containing halide-derived substances within the aforementioned range, the adsorption of noble metals by the adsorbent material is not hindered.

[0046] (Hydrophilic organic solvent)

[0047] In the precious metal recovery method disclosed herein, the liquid composition may or may not contain a hydrophilic organic solvent. It should be noted that, in this specification, "organic solvent" refers to an organic compound that is liquid at room temperature, sometimes simply called an "organic solvent." Here, "liquid" means a state of fluidity at room temperature (15–35°C). More specifically, an organic solvent refers to an organic compound that is fluid at room temperature and pressure (e.g., 15–35°C, 1 atmosphere). "Hydrophilic organic solvent" refers to an organic solvent that is miscible with water or soluble in water.

[0048] The hydrophilic organic solvent contained in the liquid composition is preferably a polar solvent. It can be either an aprotic polar solvent or a protic polar solvent.

[0049] From another perspective, a hydrophilic organic solvent can be an organic solvent having heteroatoms selected from the group consisting of nitrogen (N), sulfur (S) and oxygen (O) atoms.

[0050] Specific examples of hydrophilic organic solvents include: N-methylpyrrolidone, acetonitrile, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetone, tetrahydrofuran, propylene carbonate, methanol, ethanol, 2-propanol, n-butanol, tert-butanol, benzyl alcohol, etc. When the liquid composition contains a hydrophilic organic solvent, from the viewpoint of easily obtaining the effects of this disclosure, a preferred hydrophilic organic solvent is at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

[0051] In the case where the liquid composition contains a hydrophilic organic solvent, from the viewpoint of more efficient and better adsorption of noble metals by the adsorption material described later, the content of the hydrophilic organic solvent relative to the liquid composition as a whole can be more than 0% by mass and less than 15% by mass, can be 1% to 12% by mass, or can be 5% to 10% by mass.

[0052] (Method for manufacturing liquid composition for adsorption)

[0053] In one embodiment, the liquid composition for adsorption disclosed herein is manufactured by immersing a material containing a precious metal in a metal solution containing water and an oxidant, thereby dissolving the precious metal in the metal solution. The oxidant in the metal solution facilitates the dissolution of the precious metal. During the dissolution of the precious metal, the oxidant deteriorates or changes, thereby generating a substance derived from the oxidant. Thus, a liquid composition containing dissolved precious metal, water, and a substance derived from the oxidant is obtained. In other words, the method for manufacturing the liquid composition for adsorption disclosed herein includes the step of dissolving a precious metal in a metal solution containing water and an oxidant to obtain the liquid composition for adsorption. The amount of water in the liquid composition for adsorption is 85% by mass or more relative to the total liquid composition for adsorption.

[0054] Examples of materials containing precious metals include: waste electronic / electronic equipment, its components, processing waste from decorative items, and spent catalysts. Furthermore, semiconductors that use gold as the bonding wire connecting the electrodes of an IC chip to the lead frame can also be used as gold-containing materials.

[0055] As an oxidizing agent contained in the metal solution, the oxidizing agent described above for the liquid composition can be used. Preferred oxidizing agents are halogen molecules such as iodine (I2), bromine (Br2), and chlorine (Cl2) (X2, X = I, Br, Cl, etc.). More preferred are iodine (I2) and / or chlorine (Cl2), and even more preferred are iodine (I2).

[0056] The content of oxidant in the metal solution relative to the overall metal solution can be 0.01% to 20% by mass, 0.01% to 18% by mass, 0.01% to 15% by mass, 0.01% to 10% by mass, 0.1% to 20% by mass, 0.1% to 18% by mass, 0.1% to 15% by mass, 0.1% to 10% by mass, 1.0% to 20% by mass, 1.0% to 18% by mass, 1.0% to 15% by mass, or 1.0% to 10% by mass. Metal solutions containing oxidant within the aforementioned range are readily used for dissolving precious metals and exhibit excellent solubility.

[0057] The metal solution may contain halogen molecules (X2, X = I, Br, Cl, etc.) and halides. In the metal solution containing halides, the halogens consumed as oxidants during the dissolution of the noble metal are replenished. This maintains the solubility of the noble metal. The halides described above for the liquid composition can be used. Preferably, a halide containing the same type of halogen as the oxidant halogen molecule is preferred. In other words, a preferred metal solution contains one or more halogen molecules selected from the group consisting of iodine molecules (I2), bromine molecules (Br2), and chlorine molecules (Cl2) as oxidants, and also contains a halide containing the same type of halogen as the oxidant. The halides described above for the liquid composition are used.

[0058] For example, when the metal solution contains iodine molecules (I2) as an oxidizing agent, it is preferable to also contain an iodine compound. The iodine compound described above for the liquid composition can be used. Preferred iodine compounds are at least one selected from the group consisting of alkali metal iodides, alkaline earth metal iodides, and ammonium iodides. Furthermore, when the metal solution contains chlorine molecules (Cl2) as an oxidizing agent, it is preferable to also contain a chlorine compound. The chlorine compound described above for the liquid composition can be used. Preferred chlorine compounds are at least one selected from the group consisting of alkali metal chlorides, alkaline earth metal chlorides, and ammonium chlorides. The metal solution containing iodine molecules (I2) and chlorine molecules (Cl2) as oxidizing agents may also contain iodine compounds and chlorine compounds.

[0059] When the metal solution contains halides, the halide content relative to the overall metal solution can be 0.01% to 20% by mass, 0.01% to 18% by mass, 0.01% to 15% by mass, 0.01% to 10% by mass, 0.1% to 20% by mass, 0.1% to 18% by mass, 0.1% to 15% by mass, 0.1% to 10% by mass, 1.0% to 20% by mass, 1.0% to 18% by mass, 1.0% to 15% by mass, 1.0% to 10% by mass, 5.0% to 20% by mass, 5.0% to 18% by mass, 5.0% to 15% by mass, or 5.0% to 10% by mass. In metal solutions containing halides within the aforementioned range, excellent noble metal solubility can be maintained for a long period.

[0060] From the perspective of the excellent solubility of precious metals, the amount of water in the metal solution can be more than 0% by mass and less than 85% by mass, or less than 1% by mass and less than 80% by mass, or less than 5% by mass and 70% by mass, or less than 10% by mass and 55% by mass, relative to the overall metal solution.

[0061] The metal solvent may or may not contain a hydrophilic organic solvent. When the metal solvent contains a hydrophilic organic solvent, the hydrophilic organic solvent described above for the liquid composition can be used. Preferred hydrophilic organic solvents are at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

[0062] When the metal solution contains a hydrophilic organic solvent, the content of the hydrophilic organic solvent in the metal solution relative to the whole metal solution can be greater than 0% by mass and less than 99% by mass, can be 1% to 98% by mass, can be 5% to 97% by mass, can be 5% to 95% by mass, can be 5% to 90% by mass, can be 5% to 80% by mass, can be 10% to 98% by mass, can be 10% to 97% by mass, can be 10% to 95% by mass, can be 10% to 90% by mass, can be 10% to 80% by mass, can be 20% by mass. The range of values ​​is %–98% by mass, which can be 20%–97% by mass, which can be 20%–95% by mass, which can be 20%–90% by mass, which can be 20%–80% by mass, which can be 25%–98% by mass, which can be 25%–97% by mass, which can be 25%–95% by mass, which can be 25%–90% by mass, which can be 25%–80% by mass, which can be 30%–98% by mass, which can be 30%–97% by mass, which can be 30%–95% by mass, which can be 30%–90% by mass, which can be 30%–80% by mass. Metal solutions containing hydrophilic organic solvents within the range exhibit excellent solubility for noble metals.

[0063] In other embodiments, a liquid composition containing at least 85% by mass of water relative to the total liquid composition can be produced by adding water to a precious metal-containing liquid containing a substance derived from an oxidant and a precious metal. This precious metal-containing liquid can be obtained by immersing a material containing a precious metal in a metal solution containing an oxidant, thereby dissolving the precious metal in the material in the metal solution. In other words, the method for producing the adsorption liquid composition of this disclosure includes the step of adding water to a precious metal-containing liquid containing a substance derived from an oxidant to obtain the adsorption liquid composition. More specifically, the method for producing the adsorption liquid composition of this disclosure includes the steps of dissolving a precious metal in a metal solution containing an oxidant to obtain a precious metal-containing liquid containing a substance derived from an oxidant; and adding water to the precious metal-containing liquid to obtain the adsorption liquid composition.

[0064] As for the oxidizing agent-derived substances contained in the liquid containing precious metals, the oxidizing agent-derived substances described above for the liquid composition can be listed. Preferred oxidizing agent-derived substances are those derived from halogen molecules such as iodine (I2), bromine (Br2), and chlorine (Cl2) (X2, X = I, Br, Cl, etc.). More preferably, substances derived from iodine (I2) and / or chlorine (Cl2) molecules are preferred, and substances derived from iodine (I2) molecules are even more preferred.

[0065] Compared to the liquid containing precious metals as a whole, the content of substances derived from oxidants in the liquid containing precious metals can be 0.01% to 20% by mass, 0.1% to 18% by mass, 0.5% to 15% by mass, or 1.0% to 10% by mass.

[0066] Liquids containing noble metals may contain substances derived from halogen molecules (X2, X = I, Br, Cl, etc.) and substances derived from halides as described above for the liquid composition. Preferably, the liquid containing noble metals contains substances derived from iodine molecules (I2) and / or substances derived from chlorine molecules (Cl2) as oxidizing agents, and also contains substances derived from halides containing the same halogen as the oxidizing agent (i.e., iodine compounds and / or chlorine compounds). For example, the liquid containing noble metals contains substances derived from iodine molecules (I2) and substances derived from iodine compounds. Iodine compounds as described above for the liquid composition can be used. Preferred iodine compounds are at least one selected from the group consisting of alkali metal iodides, alkaline earth metal iodides, and ammonium iodides. Furthermore, the liquid containing noble metals may also contain substances derived from chlorine molecules (Cl2) and substances derived from chlorine compounds. Chlorine compounds as described above for the liquid composition can be used. Preferred chlorine compounds are at least one selected from the group consisting of alkali metal chlorides, alkaline earth metal chlorides, and ammonium chlorides. Liquids containing precious metals contain substances derived from iodine molecules (I2) and chlorine molecules (Cl2), and may also contain substances derived from iodine compounds and chlorine compounds.

[0067] When a liquid containing precious metals contains substances derived from halides, the content of the substances derived from halides relative to the total amount of the liquid containing precious metals may be 0.01% to 20% by mass, 0.1% to 18% by mass, 1.0% to 15% by mass, or 5.0% to 10% by mass.

[0068] Liquids containing precious metals may or may not contain water. When a liquid containing precious metals contains water, the amount of water in the liquid containing precious metals may be greater than 0% by mass and less than 85% by mass, may be 1% to less than 80% by mass, may be 5% to 70% by mass, or may be 10% to 55% by mass relative to the total amount of the liquid containing precious metals.

[0069] Liquids containing noble metals may or may not contain a hydrophilic organic solvent. When a liquid containing noble metals contains a hydrophilic organic solvent, the hydrophilic organic solvent described above for the liquid composition may be used. Preferred hydrophilic organic solvents are at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

[0070] When a liquid containing precious metals contains a hydrophilic organic solvent, the content of the hydrophilic organic solvent in the liquid containing precious metals can be greater than 0% by mass and less than 99% by mass relative to the whole liquid containing precious metals, and can be 1% to 98% by mass, 5% to 97% by mass, 10% to 95% by mass, 20% to 90% by mass, or 25% to 80% by mass.

[0071] (Adsorbent material)

[0072] In the precious metal recovery method disclosed herein, the dissolved precious metal in the liquid composition is adsorbed onto the adsorbent material by contacting a liquid composition containing dissolved precious metal. As a method of contacting the liquid composition with the adsorbent material, for example, the adsorbent material can be added to and mixed into the liquid composition, or the liquid composition can be passed in a liquid state through a cartridge (e.g., a column) filled with the adsorbent material. In other words, the adsorbent material and the cartridge containing the adsorbent material disclosed herein are used in the aforementioned precious metal recovery method. Here, a cartridge refers to a container capable of containing adsorbent material and allowing liquid flow. Typically, a cylindrical container is called a column. Further, the adsorbent material disclosed herein is a precious metal recovery adsorbent material that adsorbs the precious metal in a liquid composition containing precious metal by contacting the liquid composition, which also contains water and a substance derived from an oxidant, wherein the amount of water in the liquid composition is 85% by mass or more relative to the total liquid composition. It should be noted that the precious metal dissolved in the liquid composition may be completely adsorbed by the adsorbent material, a portion of the precious metal in the liquid composition may be adsorbed by the adsorbent material, or the precious metal that is not adsorbed by the adsorbent material may remain in the liquid composition.

[0073] The type of adsorbent is not particularly limited; an adsorbent capable of adsorbing noble metals in the above-mentioned liquid composition can be appropriately selected. An adsorbent capable of selectively adsorbing gold is preferred. In this disclosure, the adsorbent is typically a solid, preferably a porous material. Adsorbents in various shapes, such as powder, granules, and fibers, can be used.

[0074] From the perspective of high adsorption efficiency for precious metals, the preferred adsorption material is at least one selected from the group consisting of cellulose derivatives, ion exchange resins, and activated carbon. Cellulose derivatives are more preferred as the adsorption material.

[0075] In this specification, "cellulose derivative" is defined as a general term for compounds in which at least a portion of the hydroxyl groups in cellulose are introduced with various substituents. Preferred cellulose derivatives are cellulose esters in which at least a portion of the hydroxyl groups in cellulose are esterified. More preferred are cellulose esters with a total degree of substitution of 0.8 or more and 2.9 or less. From the perspective of selectively adsorbing gold, the total degree of substitution of cellulose esters can be 0.8–2.9, 1.0–2.9, 1.2–2.9, 1.5–2.9, 1.8–2.9, 2.0–2.9, 2.3–2.9, 0.8–2.8, 1.0–2.8, 1.2–2.8, 1.5–2.8, 1.8–2.8, 2.0–2.8, 2.3–2.8, 0.8–2.7, 1.0–2.7, 1.2–2.7, 1.5–2.7, 1.8–2.7, 2.0–2.7, or 2.3–2.7. The total degree of substitution of cellulose ester is the sum of the degrees of substitution at positions 2, 3, and 6 of the glucose ring of the cellulose ester, and can be determined by NMR, for example, according to the method of Tezuka (Carbonydr. Res. 273, 83 (1995)).

[0076] The preferred cellulose derivative is a cellulose acylated product formed by replacing at least some of the hydroxyl groups in cellulose with acyl groups having 2 to 40 carbon atoms. The acyl groups of the cellulose ester can have 2 to 30, 2 to 20, 2 to 10, 2 to 5, or 2 to 3 carbon atoms. From the perspective of selectively adsorbing gold, the degree of substitution of the acyl group in the cellulose acylate can be 0.8–2.9, 1.0–2.9, 1.2–2.9, 1.5–2.9, 1.8–2.9, 2.0–2.9, 2.3–2.9, 0.8–2.8, 1.0–2.8, 1.2–2.8, 1.5–2.8, 1.8–2.8, 2.0–2.8, 2.3–2.8, 0.8–2.7, 1.0–2.7, 1.2–2.7, 1.5–2.7, 1.8–2.7, 2.0–2.7, or 2.3–2.7. The degree of substitution of the acyl groups in cellulose acylates is the sum of the degrees of substitution of the acyl groups at positions 2, 3, and 6 of the glucose ring of the cellulose ester, and can be determined in the same way as the method for determining the total degree of substitution of cellulose derivatives described above.

[0077] Preferably, the cellulose derivative is cellulose acetate formed by replacing at least a portion of the hydroxyl groups in cellulose with acetyl groups. More preferably, it is cellulose acetate with an acetyl substitution degree of 0.8 or more and 2.9 or less. From the viewpoint of selectively adsorbing gold, the acetyl substitution degree of cellulose acetate can be 0.8 to 2.9, 1.0 to 2.9, 1.2 to 2.9, 1.5 to 2.9, 1.8 to 2.9, 2.0 to 2.9, 2.3 to 2.9, 0.8 to 2.8, 1.0 to 2.8, 1.2 to 2.8, 1.5 to 2.8, 1.8 to 2.8, 2.0 to 2.8, 2.3 to 2.8, 0.8 to 2.7, 1.0 to 2.7, 1.2 to 2.7, 1.5 to 2.7, 1.8 to 2.7, 2.0 to 2.7, or 2.3 to 2.7. The degree of acetyl substitution of cellulose ester is the sum of the degrees of substitution of each acetyl group at positions 2, 3, and 6 of the glucose ring of the cellulose ester, and can be determined in the same way as the method for determining the total degree of substitution of cellulose derivatives described above.

[0078] When the adsorbent material is cellulose acetate, within the scope of the effects disclosed herein, cellulose acetate may also contain substituents other than acetyl. Examples of such substituents include: propionyl, butyryl, valeryl, hexanoyl, heptanoyl, octanoyl, nonanoyl, undecanoyl, dodecanoyl, tridecanoyl, tetradecanoyl (myristoyl), pentadecanoyl, hexadecanoyl, heptadecanoyl, and octadecanoyl (stearoyl).

[0079] In this specification, "ion exchange resin" is defined as a resin composed of cross-linked polymers possessing ion exchange groups and containing counterions capable of exchanging with target ions. Any type of ion exchange resin capable of ion exchange in the presence of an organic solvent can be used, and the type can be appropriately selected based on the type of target ion. Examples of ion exchange resins include: polyolefins, (meth)acrylic resins, styrene resins, polyacetals, polyesters, polycarbonates, polyamides, polyamide-imides, polyimides, polyethers, polyetherimides, polyetherketones, polyetheretherketones, polysulfones, polyethersulfones, polyphenylene sulfide, and fluoropolymers, etc., possessing ion exchange groups. Examples of ion exchange groups include: sulfonic acid groups, carboxyl groups, phosphate groups, primary amino groups, secondary amino groups, tertiary amino groups, and quaternary ammonium groups, etc. Anion exchange resins capable of exchanging negative ions are particularly preferred.

[0080] In this specification, "activated carbon" is defined as a material substantially composed of carbon and having multiple pores on its surface. There are no particular limitations on the type of activated carbon, and it is unrelated to its source, activation method, or shape; commercially available, known activated carbon can be appropriately selected. For example, it can be mineral-derived activated carbon, plant-derived activated carbon, resin-derived activated carbon, steam-activated activated carbon, or chemically activated activated carbon. The shape of activated carbon can be appropriately selected as powder, granules, crushed, fibrous, honeycomb, etc.

[0081] When activated carbon is selected as the adsorption material, its specific surface area is preferably 200–3500 m². 2 / g, more preferably 400-2000m 2 / g, further preferably 800-2000m 2 / g. In addition, the total pore volume of activated carbon is preferably 0.1 to 2 ml / g, more preferably 0.2 to 1.6 ml / g, and even more preferably 0.2 to 0.8 ml / g.

[0082] The amount of adsorbent added can be appropriately selected according to the type of adsorbent. From the viewpoint of efficiently adsorbing gold, the amount of adsorbent added relative to the composition can be 1 g / L to 1000 g / L, 1 g / L to 500 g / L, 1 g / L to 300 g / L, 1 g / L to 200 g / L, 1 g / L to 100 g / L, 2 g / L to 1000 g / L, 2 g / L to 500 g / L, 2 g / L to 300 g / L, 2 g / L to 200 g / L, 2 g / L to 100 g / L, 5 g / L to 1000 g / L, or 5 g / L to 500 g / L. / L, can be 5g / L~300g / L, can be 5g / L~200g / L, can be 5g / L~100g / L, can be 10g / L~1000g / L, can be 10g / L~500g / L, can be 10g / L~300g / L, can be 10g / L~200g / L, can be 10g / L~100g / L, can be 15g / L~1000g / L, can be 15g / L~500g / L, can be 15g / L~300g / L, can be 15g / L~200g / L, can be 15g / L~100g / L.

[0083] In the precious metal recovery method disclosed herein, by contacting the adsorbent material with the liquid composition, the precious metals dissolved in the liquid composition are preferentially adsorbed by the adsorbent material. However, occasionally, substances other than precious metals (e.g., halide ions such as chloride ions, halogen molecules, etc.) originating from oxidants, halides, etc., may also be adsorbed. In this case, by pre-adsorbing the target substance (substance originating from oxidants or substances originating from halides) onto the adsorbent material before contacting it with the liquid composition, the adsorption of substances other than precious metals in the liquid composition can be suppressed. In other words, the precious metal recovery method disclosed herein may further include a step of adsorbing substances originating from oxidants onto the adsorbent material before contacting the liquid composition with the adsorbent material, which may include a step of adsorbing substances originating from oxidants and / or substances originating from halides onto the adsorbent material.

[0084] By contacting a liquid composition with an adsorbent material, a precious metal-containing adsorbent material can be obtained, which adsorbs the precious metal in the liquid composition. By separating the precious metal-containing adsorbent material from the liquid composition, the precious metal adsorbed by the precious metal-containing adsorbent material can be recovered.

[0085] There are no particular limitations on the method for separating adsorbent materials containing precious metals; general solid-liquid separation methods can be used. Examples of solid-liquid separation methods include filtration, centrifugation, and sedimentation.

[0086] As a method for recovering precious metals from adsorbents containing precious metals, for example, the precious metals can be released from the adsorbents using a desorption solution to recover the precious metals dissolved in the desorption solution, or the adsorbents containing precious metals can be incinerated to recover the precious metals in the form of incineration residue. Examples of methods using a desorption solution include passing the desorption solution in liquid form through an adsorbent containing precious metals packed in a cylinder (e.g., a column), and adding the adsorbent containing precious metals to the desorption solution and stirring.

[0087] The type of desorption solution can be selected based on the type of adsorbent. For example, in the case of adsorbents formed from cellulose derivatives, preferred desorption solutions include water and aqueous sodium chloride solutions.

[0088] (use)

[0089] The disclosed method for recovering precious metals and the liquid composition for adsorption are used to recover precious metals from waste electrical / electronic equipment and to extract precious metals from ores, etc., using adsorption materials. Furthermore, it can also be applied to recover precious metals from etching solutions used in semiconductor manufacturing processes.

[0090] Example

[0091] The present disclosure will now be specifically described through examples, but the technical scope of the present disclosure is not limited to these examples. It should be noted that, unless otherwise specified, the test temperature is room temperature.

[0092] [Example 1]

[0093] (Preparation of metal solution)

[0094] A metal solution (1) was prepared by mixing N-methylpyrrolidone (manufactured by Kanto Chemical Co., Ltd., 38% by weight), iodine (I2, manufactured by Kanto Chemical Co., Ltd., 3% by weight), ammonium iodide (manufactured by FUJIFILM Wako Pure Chemical Co., Ltd., 7% by weight) and water (52% by weight). The composition of the metal solution (1) is shown in Table 1 below.

[0095] Gold wire (φ=0.20mm, purity 99.95%, manufactured by Nilaco Co., Ltd.) was added to the obtained metal solution (1) and dissolved. Then, 900 parts by mass of water were added relative to 100 parts by mass of the metal solution (1), thereby obtaining an adsorption liquid composition (1) with a water content of 95.2 wt.% and a gold concentration of 89 ppm. The water content and the concentration of dissolved gold in the adsorption liquid composition (1) are shown in Table 1 below as "water (in the adsorption liquid composition)" and "initial gold concentration (M1)".

[0096] (Adsorption test)

[0097] Adsorbent A (cellulose acetate, degree of acetyl substitution 2.5) was added to the obtained liquid composition (1) for adsorption to adsorb gold dissolved in the liquid composition (1). The amount of adsorbent A added was set to 2 g (g / L) relative to the liquid composition (1). After stirring at room temperature for 3 hours, the gold-adsorbed adsorbent A (gold-containing adsorbent) was subjected to solid-liquid separation, and the gold concentration in the liquid phase was determined. In the determination of gold concentration, the ICP emission spectrum was measured using an inductively coupled plasma atomic emission spectrometer (trade name "Agilent 5110", manufactured by Agilent Technologies). The gold concentration before adsorption was set as M1 (ppm), and the gold concentration after adsorption was set as M2 (ppm), and the gold adsorption rate X (%) of the adsorbent was calculated by the following formula. The result is shown in Table 1 below as "Gold Adsorption Rate (%)".

[0098] X(wt%)=(M1(ppm)-M2(ppm)) / M1(ppm)×100

[0099] [Example 2]

[0100] The amount of adsorbent material and the gold concentration in the liquid composition for adsorption were changed to the amounts and concentrations shown in Table 1 below. Otherwise, the adsorption test was performed in the same manner as in Example 1. The composition of the metal solution and the results of the adsorption test are shown in Table 1 below. In addition, the water content of the liquid composition for adsorption (2) and the concentration of dissolved gold are shown in Table 1 below as “Water (in the liquid composition for adsorption)” and “Initial gold concentration (M1)”, respectively.

[0101] [Examples 3-4]

[0102] The composition of the metal solution was changed to that shown in Table 1 below, and the adsorption test was performed in the same manner as in Example 1. The composition of the metal solution and the results of the adsorption test are shown in Table 1 below. In addition, the water content and the concentration of dissolved gold in the liquid composition (3) and (4) for adsorption are shown in Table 1 below as “water (in the liquid composition for adsorption)” and “initial gold concentration (M1)”, respectively.

[0103] [Example 5]

[0104] A metal solution (5) was prepared by mixing iodine (I2, manufactured by Kanto Chemical Co., Ltd., 5% by weight), ammonium iodide (manufactured by FUJIFILM Wako PureChemical Co., Ltd., 10% by weight) and water (85% by weight). The composition of the metal solution (5) is shown in Table 1 below.

[0105] Gold wire (φ=0.20mm, purity 99.95%, manufactured by Nilaco Co., Ltd.) was added to the obtained metal solution (5) and dissolved to obtain an adsorption liquid composition (5) with a water content of 85 wt.% and a gold concentration of 190 ppm. The water content and the concentration of dissolved gold in the adsorption liquid composition (5) are shown in Table 1 below as "Water (in the adsorption liquid composition)" and "Initial gold concentration (M1)".

[0106] Adsorbent A (cellulose acetate, degree of acetyl substitution 2.5) was added to the obtained liquid composition (5) for adsorption to adsorb gold dissolved in the liquid composition (5). The amount of adsorbent A added was set to 20 g (g / L) relative to the adsorption composition (1). After stirring at room temperature for 3 hours, the gold-adsorbed adsorbent A (gold-containing adsorbent) was subjected to solid-liquid separation, and the gold adsorption rate of the adsorbent was determined by the method described in Example 1. The results are shown in Table 1 below as "Gold Adsorption Rate (%)".

[0107] [Comparative Example 1]

[0108] A metal solution (Cl) was prepared by mixing N-methylpyrrolidone (manufactured by Kanto Chemical Co., Ltd., 38% by weight), iodine (I2, manufactured by Kanto Chemical Co., Ltd., 3% by weight), ammonium iodide (manufactured by FUJIFILM Wako Pure Chemical Co., Ltd., 7% by weight), and water (52% by weight). The composition of the metal solution is shown in Table 1 below.

[0109] Gold wire (φ=0.20mm, purity 99.95%, manufactured by Nilaco Co., Ltd.) was added to the obtained metal solution (C1) and dissolved to obtain an adsorption liquid composition (C1) with a water content of 52 wt.% and a gold concentration of 1600 ppm. The water content and the concentration of dissolved gold in this adsorption liquid composition (C1) are shown in Table 1 below as "Water (in the adsorption liquid composition)" and "Initial gold concentration (M1)".

[0110] The adsorption test was performed in the same manner as in Example 1, except that the obtained liquid composition for adsorption (C1) was used. The results are shown in Table 1 below. In the adsorption test of Comparative Example 1, gold could not be recovered from the adsorbent material.

[0111] [Comparative Examples 2-3]

[0112] After dissolving gold in a metal solution in the same manner as in Comparative Example 1, water was added in the amount listed in Table 1 relative to 100 parts by mass of the metal solution, thereby obtaining an adsorption liquid composition (C2) with a water content of 84 wt.% and a gold concentration of 533 ppm and an adsorption liquid composition (C3) with a water content of 70 wt.% and a gold concentration of 1000 ppm.

[0113] Adsorption tests were performed in the same manner as in Comparative Example 1, except that liquid adsorption compositions (C2) and (C3) were used instead of liquid adsorption composition (C1). The composition of the metal solution and the results of the adsorption tests are shown in Table 1 below. Furthermore, the water content and the concentration of dissolved gold in liquid adsorption compositions (C2) and (C3) are shown in Table 1 as "Water (in liquid adsorption composition)" and "Initial gold concentration (M1)", respectively. Comparative Examples 2-3 were unable to recover gold using the adsorption material.

[0114] [Table 1]

[0115]

[0116] As shown in Table 1, in the examples where the amount of water in the liquid composition for adsorption is 85% by mass or more, dissolved precious metals can be efficiently recovered by the adsorption material. On the other hand, in the comparative examples where the amount of water is less than 85% by mass, dissolved precious metals cannot be recovered by the adsorption material. Based on these evaluation results, the advantages of this disclosure are obvious.

[0117] [Public Projects]

[0118] Preferred implementations of the following projects are disclosed.

[0119] [Project 1]

[0120] A method for recovering a precious metal, comprising: contacting a liquid composition containing the precious metal with an adsorbent material to adsorb the precious metal in the liquid composition onto the adsorbent material, and recovering the precious metal, wherein the liquid composition further comprises water and a substance derived from an oxidant, and the amount of water in the liquid composition is 85% by mass or more relative to the total liquid composition.

[0121] [Project 2]

[0122] According to the precious metal recovery method of Project 1, the recovery method further comprises: adjusting the amount of water in the liquid composition to more than 85% by mass of the total liquid composition before contacting the adsorbent material.

[0123] [Project 3]

[0124] The method for recycling precious metals according to Project 1 or 2, wherein the precious metal is gold.

[0125] [Project 4]

[0126] The method for recovering precious metals according to any one of items 1 to 3, wherein the substance derived from the oxidant is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2).

[0127] [Project 5]

[0128] The method for recovering precious metals according to any one of items 1 to 4, wherein the substance derived from the oxidant is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2), and the liquid composition further comprises a substance derived from a halide, the halide comprising the same type of halogen as the substance derived from the oxidant.

[0129] [Project 6]

[0130] According to the precious metal recovery method described in Project 5, the halide is at least one selected from the group consisting of alkali metal halides, alkaline earth metal halides, and ammonium halides.

[0131] [Project 7]

[0132] The method for recovering precious metals according to any one of items 1 to 6, wherein the adsorbent material is selected from at least one of the group consisting of cellulose derivatives, ion exchange resins and activated carbon.

[0133] [Project 8]

[0134] According to the precious metal recovery method described in Project 7, the cellulose derivative is a cellulose ester with a total degree of substitution of 0.8 or more and 2.9 or less.

[0135] [Project 9]

[0136] According to the precious metal recovery method described in Project 7 or 8, the cellulose derivative is cellulose acetate in which at least a portion of the hydroxyl groups are replaced by acetyl groups.

[0137] [Project 10]

[0138] The method for recovering precious metals according to any one of items 1 to 9, wherein the liquid composition further comprises a hydrophilic organic solvent.

[0139] [Project 11]

[0140] According to the precious metal recovery method described in Project 10, the hydrophilic organic solvent is an organic solvent with heteroatoms.

[0141] [Project 12]

[0142] According to the precious metal recovery method described in Project 10 or 11, the hydrophilic organic solvent is a polar solvent.

[0143] [Project 13]

[0144] The method for recovering precious metals according to any one of items 10 to 12, wherein the hydrophilic organic solvent is at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

[0145] [Project 14]

[0146] An adsorbent material for use in a method for recovering precious metals according to any one of items 1 to 13.

[0147] [Project 15]

[0148] A cartridge comprising the adsorbent material as described in item 14.

[0149] [Project 16]

[0150] An adsorption liquid composition for use in a method for recovering precious metals according to any one of items 1 to 13, the adsorption liquid composition comprising water, a substance derived from an oxidant, and a precious metal, wherein the amount of water is 85% by mass or more relative to the total amount of the adsorption liquid composition.

[0151] [Project 17]

[0152] According to the liquid composition for adsorption described in Project 16, the noble metal is gold.

[0153] [Project 18]

[0154] According to the liquid composition for adsorption described in item 16 or 17, the substance derived from the oxidant is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2).

[0155] [Project 19]

[0156] The liquid composition for adsorption according to any one of items 16 to 18, wherein the substance derived from the oxidant is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2), and the liquid composition for adsorption further comprises a substance derived from a halide, the halide comprising the same halogen as the substance derived from the oxidant, and the halide being at least one selected from the group consisting of alkali metal halides, alkaline earth metal halides, and ammonium halides.

[0157] [Project 20]

[0158] The liquid composition for adsorption according to any one of items 16 to 19, wherein the liquid composition for adsorption further comprises a hydrophilic organic solvent, said hydrophilic organic solvent being at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

[0159] [Project 21]

[0160] A method for manufacturing an adsorption liquid composition, wherein the method for manufacturing an adsorption liquid composition according to any one of items 16 to 20 comprises: a step of dissolving a noble metal in a metal solution containing water and an oxidant to obtain an adsorption liquid composition, wherein the amount of water in the adsorption liquid composition is 85% by mass or more relative to the total amount of the adsorption liquid composition.

[0161] [Project 22]

[0162] A method for manufacturing an adsorption liquid composition, the method being the method for manufacturing an adsorption liquid composition according to any one of items 16 to 20, the method comprising: adding water to a precious metal-containing liquid comprising a substance derived from an oxidant and a precious metal to obtain an adsorption liquid composition, wherein the amount of water in the adsorption liquid composition is 85% by mass or more relative to the total amount of the adsorption liquid composition.

[0163] Industrial availability

[0164] The recycling methods described above can be applied not only to recovering precious metals from scrap equipment, but also to recovering precious metals from etching solutions.

Claims

1. A method for recycling precious metals, the method comprising: The step of recovering the precious metal by contacting a liquid composition containing a precious metal with an adsorbent material, thereby adsorbing the precious metal in the liquid composition onto the adsorbent material. The liquid composition also includes water and substances derived from an oxidant. The amount of water in the liquid composition is 85% by mass or more relative to the total liquid composition.

2. The method for recovering precious metals according to claim 1, wherein, The recovery method further comprises the step of adjusting the amount of water in the liquid composition to more than 85% by mass of the total liquid composition before contacting the adsorbent material.

3. The method for recovering precious metals according to claim 1, wherein, The precious metal in question is gold.

4. The method for recovering precious metals according to claim 1, wherein, The substance derived from the oxidant is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2).

5. The method for recovering precious metals according to claim 1, wherein, The substance derived from the oxidizing agent is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2). The liquid composition further comprises a substance derived from a halide, the halide containing the same type of halogen as the substance derived from the oxidant.

6. The method for recovering precious metals according to claim 5, wherein, The halide is at least one selected from the group consisting of alkali metal halides, alkaline earth metal halides, and ammonium halides.

7. The method for recovering precious metals according to claim 1, wherein, The adsorption material is selected from at least one of the following groups: cellulose derivatives, ion exchange resins, and activated carbon.

8. The method for recovering precious metals according to claim 7, wherein, The cellulose derivative is a cellulose ester with a total degree of substitution of 0.8 or more and 2.9 or less.

9. The method for recovering precious metals according to claim 7, wherein, The cellulose derivative is cellulose acetate in which at least some of the hydroxyl groups are replaced by acetyl groups.

10. The method for recovering precious metals according to claim 1, wherein, The liquid composition also contains a hydrophilic organic solvent.

11. The method for recovering precious metals according to claim 10, wherein, The hydrophilic organic solvent is an organic solvent containing heteroatoms.

12. The method for recovering precious metals according to claim 10, wherein, The hydrophilic organic solvent is a polar solvent.

13. The method for recovering precious metals according to claim 10, wherein, The hydrophilic organic solvent is at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

14. An adsorbent material used in the method for recovering precious metals according to claim 1.

15. A cartridge comprising the adsorbent material according to claim 14.

16. A liquid composition for adsorption, said liquid composition for use in the method for recovering precious metals according to claim 1. The adsorption liquid composition comprises water, a substance derived from an oxidant, and a noble metal. The amount of water is 85% by mass or more relative to the total amount of the liquid composition for adsorption.

17. The liquid composition for adsorption according to claim 16, wherein, The precious metal in question is gold.

18. The liquid composition for adsorption according to claim 16, wherein, The substance derived from the oxidant is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2).

19. The liquid composition for adsorption according to claim 16, wherein, The substance derived from the oxidizing agent is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2). The liquid composition for adsorption further comprises a substance derived from a halide, the halide containing the same type of halogen as the substance derived from the oxidant. The halide is at least one selected from the group consisting of alkali metal halides, alkaline earth metal halides, and ammonium halides.

20. The liquid composition for adsorption according to claim 16, wherein, The liquid composition for adsorption also contains a hydrophilic organic solvent. The hydrophilic organic solvent is at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

21. A method for manufacturing an adsorption liquid composition, wherein the method for manufacturing the adsorption liquid composition is the method for manufacturing an adsorption liquid composition according to claim 16, the method comprising: The step of dissolving a precious metal in a metal solution containing water and an oxidant to obtain a liquid composition for adsorption. The amount of water in the liquid composition for adsorption is 85% by mass or more, relative to the total amount of the liquid composition for adsorption.

22. A method for manufacturing an adsorption liquid composition, wherein the method for manufacturing the adsorption liquid composition is the method for manufacturing an adsorption liquid composition according to claim 16, the method comprising: The step of adding water to a precious metal-containing liquid containing a substance derived from an oxidant and a precious metal to obtain an adsorption liquid composition. The amount of water in the liquid composition for adsorption is 85% by mass or more, relative to the total amount of the liquid composition for adsorption.

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