Method for recovering noble metal and liquid composition for adsorption

Abstract

To provide a recovery method for efficiently recovering dissolved noble metals using an adsorbent, and a liquid composition for adsorption used in the recovery method.SOLUTION: A method for recovering a noble metal comprises bringing a liquid composition containing a noble metal into contact with an adsorbent to adsorb the noble metal in the liquid composition onto the adsorbent, thereby recovering the noble metal. The liquid composition further contains water and an oxidizing agent-derived substance. The amount of water in the liquid composition is 85 mass% or more with respect to the entire liquid composition. The liquid composition for adsorption used in the recovery method contains water, an oxidizing agent-derived substance, and a noble metal. The amount of the water therein is 85 mass% or more with respect to the whole liquid composition for adsorption.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for recovering precious metals, and more particularly to a method for recovering precious metals using an adsorbent and a liquid adsorption composition used in the recovery method. [Background technology]

[0002] In recent years, many electrical and electronic devices, such as mobile phones, are being used and discarded. These devices contain various metals, including precious and rare metals. Therefore, discarded electrical and electronic devices have been attracting attention as "urban mines" for extracting precious metals. Gold (Au), in particular, is a material used in bonding wires that connect IC chip electrodes to lead frames, and is used in large quantities. Therefore, there is a need for technology to efficiently recover gold from urban mines.

[0003] To recover precious metals from used equipment, such as urban mines, it is first necessary to use a metal dissolving solution to dissolve the precious metals in the used equipment. Recently, "organic aqua regia," which contains an organic solvent and copper halide, has become known as a solvent (metal dissolving solution) for dissolving gold. In organic aqua regia, the copper halide, an oxidizing agent, contributes to the dissolution of gold. A method has been proposed in which the gold contained in used electrical and electronic equipment is dissolved in this organic aqua regia, and then the gold in the solution is recovered. Furthermore, an "etching solution" composed of an organic solvent and an elemental halogen is known for etching semiconductors containing precious metals. In this etching solution, the oxidizing agent iodine contributes to the dissolution of gold.

[0004] For example, Japanese Patent No. 6196662 (Patent Document 1) proposes a gold recovery method including 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 dissolved gold to precipitate the precious metal. Japanese Patent Laid-Open Publication No. 2-310326 (Patent Document 2) discloses a technique in which a porous granular resin is impregnated with dibutyl carbitol or methyl isobutyl ketone as an organic solvent, and then a hydrochloric acid solution containing gold is passed through the porous granular resin layer to selectively extract gold into dibutyl carbitol or methyl isobutyl ketone. Japanese Patent Laid-Open Publication No. 2002-194450 (Patent Document 3) proposes a method for selectively adsorbing platinum group precious metals from an organic solvent solution using an adsorbent containing nicotinamide as an active ingredient. Japanese Patent Laid-Open Publication No. 2004-211142 (Patent Document 4) discloses an iodine-based etching solution containing a water-compatible organic solvent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6196662 [Patent Document 2] Japanese Patent Application Publication No. 2-310326 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-194450 [Patent Document 4] Japanese Patent Application Laid-Open No. 2004-211142 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, a solvent system containing copper halide is used to dissolve gold. Therefore, there is a concern about contamination with other metals (copper) when recovering gold. Furthermore, Patent Document 1 does not disclose any knowledge about recovering gold dissolved in an organic solvent system using an adsorbent. The technology disclosed in Patent Document 2 requires a re-extraction process using dilute acid to recover gold extracted by the metal extractant, which requires time and effort. Nicotinamide, the active ingredient in Patent Document 3, dissolves in organic solvents and therefore needs to be supported on an insoluble material such as activated carbon. Furthermore, although nicotinamide has excellent selectivity for platinum group precious metals, it cannot be used to recover gold. Patent Document 4 does not mention the recovery of dissolved precious metals.

[0007] An object of the present disclosure is to provide a precious metal recovery method that can efficiently adsorb dissolved precious metals onto an adsorbent and recover them. Another object of the present disclosure is to provide a liquid composition for adsorption that contains dissolved precious metals and that can be highly efficiently recovered by the adsorbent. [Means for solving the problem]

[0008] The method for recovering precious metals according to the present disclosure includes contacting a liquid composition containing precious metals with an adsorbent to adsorb the precious metals in the liquid composition onto the adsorbent, thereby recovering the precious metals. The liquid composition further contains water and an oxidant-derived substance. The amount of water in the liquid composition is 85 mass% or more of the total liquid composition.

[0009] The liquid adsorption composition according to the present disclosure is used in the method for recovering precious metals. The liquid adsorption composition contains water, an oxidant-derived substance, and precious metals. The amount of water is 85 mass% or more of the total liquid adsorption composition.

[0010] The method for producing the liquid composition for adsorption described above includes dissolving a precious metal in a metal dissolving solution containing water and an oxidizing agent to obtain a liquid composition for adsorption, wherein the amount of water in the liquid composition for adsorption is 85 mass % or more based on the total amount of the liquid composition for adsorption.

[0011] The method for producing the liquid composition for adsorption may include adding water to a precious metal-containing liquid containing an oxidizing agent-derived substance and a precious metal to obtain the liquid composition for adsorption, wherein the amount of water in the liquid composition for adsorption is 85 mass % or more based on the total amount of the liquid composition for adsorption. [Effects of the Invention]

[0012] According to the precious metal recovery method of the present disclosure, dissolved precious metals can be efficiently adsorbed onto an adsorbent and recovered. The precious metals contained in the liquid adsorption composition of the present disclosure have a high adsorption rate to the adsorbent. This liquid adsorption composition can be easily produced by minimizing the amount of organic solvents, which have a high environmental impact, and without using mineral acids. DETAILED DESCRIPTION OF THE INVENTION

[0013] An example of a preferred embodiment will be described in detail below. Each configuration and combination thereof in each embodiment is merely an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate within the scope of the present disclosure. The present disclosure is not limited by the embodiments, but only by the scope of the claims. Furthermore, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

[0014] The numerical range of each requirement disclosed herein can be arbitrarily combined with the numerical range of other requirements. For example, the numerical range limit for the degree of acetyl substitution of a cellulose resin can be combined with the numerical range limit for the molecular weight. Furthermore, the numerical range of each requirement disclosed herein can be any range obtained by arbitrarily combining the upper and lower limits.

[0015] In this specification, the term "X to Y" indicating a range means "X or more and Y or less," "ppm" means "ppm by mass," and "%" means "% by mass (wt.%)." Furthermore, "% by mass" refers to weight percent, and does not mean mass concentration. Furthermore, "X' and / or Y'" means "at least one selected from the group consisting of X' and Y'," and includes all of [1] to [3] of "[1] X' only, [2] Y' only, and [3] both X' and Y'." Unless otherwise noted, all test temperatures in this specification are room temperature (20°C ± 5°C).

[0016] (Method of recovering precious metals) The present disclosure relates to a technique for recovering precious metals from a liquid composition containing dissolved precious metals using an adsorbent. The present inventors discovered that the amount of water in the liquid composition containing precious metals significantly affects the adsorption efficiency of the precious metals onto the adsorbent, and have completed the technique of the present disclosure.

[0017] That is, the precious metal recovery method of the present disclosure includes contacting a liquid composition containing a precious metal with an adsorbent, thereby adsorbing the precious metal in the liquid composition onto the adsorbent and recovering the precious metal. This liquid composition further contains water and an oxidant-derived substance. In this recovery method, the amount of water in the liquid composition is 85 mass% or more relative to the entire liquid composition. In the precious metal recovery method of the present disclosure, the amount of water contained in the liquid composition is 85 mass% or more relative to the entire liquid composition, thereby promoting adsorption of the precious metal onto the adsorbent. According to the precious metal recovery method of the present disclosure, precious metals can be efficiently recovered by the simple method of adding an adsorbent to a liquid composition containing dissolved precious metals.

[0018] (Liquid composition for adsorption) The liquid composition for adsorption of the present disclosure is a liquid composition used in the above-described method for recovering precious metals, and refers to the liquid composition at the time of contacting with the adsorbent. Unless otherwise specified, the terms "liquid composition" and "liquid composition for adsorption" are used interchangeably herein.

[0019] The liquid composition for adsorption of the present disclosure contains a dissolved precious metal, water, and an oxidant-derived substance. The amount of water contained in the liquid composition for adsorption is 85 mass% or more based on the total amount of the liquid composition for adsorption. By contacting the liquid composition for adsorption containing 85 mass% of water based on the total amount of the liquid composition for adsorption with an adsorbent, the precious metal in the liquid composition for adsorption is adsorbed onto the adsorbent.

[0020] From the viewpoint of improving the adsorption rate of the precious metal, the amount of water in the liquid composition may be more than 85 mass% and less than 100 mass%, may be 88 mass% to 99 mass%, may be 90 mass% to 98 mass%, may be 92 mass% to 97 mass%, or may be 94 mass% to 96 mass%, relative to the entire liquid composition.

[0021] From the viewpoint of improving the adsorption rate of the precious metal, this precious metal recovery method may further include a step of adjusting the amount of water in the liquid composition to 85% by mass or more of the total amount of the liquid composition before contact with the adsorbent. For example, the amount of water in the liquid composition can be adjusted to 85% by mass or more by adding water after dissolving the precious metal in a metal dissolving liquid described below.

[0022] In other words, a method for recovering precious metals according to one embodiment of the present disclosure includes: (1) dissolving a precious metal in a metal-dissolving solution to obtain a composition containing a metal-dissolving solution and dissolved gold; (2) adding water to this composition to obtain a liquid composition containing water in an amount of 85% by mass or more; and (3) contacting this liquid composition with an adsorbent to adsorb the dissolved precious metal onto the adsorbent and recover the precious metal.

[0023] In another embodiment, the precious metal recovery method of the present disclosure may include: (1) dissolving a precious metal in a metal solution to obtain a composition containing a metal solution and dissolved gold; (2) adding water to the composition to obtain a liquid composition containing 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) separating the precious metal-containing adsorbent from the liquid composition to recover the precious metal in the precious metal-containing adsorbent.

[0024] Here, "precious metal" refers to gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh), ruthenium (Ru), and osmium (Os). That is, the target of the precious metal recovery method of the present disclosure may be one or more 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 described below, the target precious metal can be selected and recovered.

[0025] Preferably, the target of the precious metal recovery method of the present disclosure is gold (Au). That is, the liquid composition of the present disclosure may contain dissolved gold, water, and an oxidizing agent-derived substance. The amount of water in this liquid composition is 85 mass% or more based on the total amount of the liquid composition. The technical scope of the present disclosure also includes a gold recovery method that includes contacting this liquid composition with an adsorbent to adsorb the gold in the liquid composition onto the adsorbent and recovering the gold.

[0026] The concentration of the precious metal in the liquid composition is not particularly limited, but for example, the concentration of the precious metal may 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, relative to the entire liquid composition.

[0027] (oxidant-derived substances) In this specification, the term "oxidizing agent-derived substance" refers to a substance resulting from the alteration or change of an oxidizing agent. In the present disclosure, the oxidizing agent-derived substance in the liquid composition may be a substance derived from the oxidizing agent in the metal-dissolving solution for dissolving a precious metal, or may be a substance resulting from the alteration or change during the process of dissolving a precious metal in a metal-dissolving solution containing an oxidizing agent. Note that the liquid composition may contain the oxidizing agent itself, as long as the effects of the present disclosure are obtained.

[0028] For example, oxidizing agents that produce oxidant-derived substances include halogen molecules (X, X = I, Br, Cl, etc.) such as iodine molecules (I), bromine molecules (Br), and chlorine molecules (Cl). In other words, the oxidant-derived substance in the liquid composition may be one or more selected from the group consisting of substances derived from iodine molecules (I), substances derived from bromine molecules (Br), and substances derived from chlorine molecules (Cl), preferably substances derived from iodine molecules (I) and / or substances derived from chlorine molecules (Cl), and more preferably substances derived from iodine molecules (I).

[0029] When the oxidizing agent-derived substance in the liquid composition is adsorbed by the adsorbent, the adsorption of the precious metal to be recovered may be inhibited. From the viewpoint of improving the adsorption rate of the precious metal, the content of the oxidizing agent-derived substance in the liquid composition may be 0.01 mass % to 20 mass %, 0.1 mass % to 18 mass %, 0.5 mass % to 15 mass %, or 1.0 mass % to 10 mass % with respect to the entire liquid composition.

[0030] (Other additives) When the liquid composition contains a substance derived from a halogen molecule (X2, X=I, Br, Cl, etc.) as an oxidizing agent-derived substance, the liquid composition may further contain a substance derived from a halide. Preferably, the liquid composition contains a substance derived from a halide containing the same halogen as the halogen molecule. A preferred 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-derived substance, and further contains a substance derived from a halide containing the same halogen as the oxidizing agent-derived substance (i.e., an iodine compound and / or a chlorine compound). Examples of such halides include alkali metal halides, alkaline earth metal halides, and ammonium halides. In this specification, "ammonium" refers to ammonium (NH4 + ) and organic ammonium (quaternary ammonium, NR4 + , R=hydrocarbon group).

[0031] For example, the liquid composition may contain a substance derived from an iodine compound along with a substance derived from iodine molecules (I2) as an oxidizing agent. In other words, the oxidizing agent-derived substance in this liquid composition may be a substance derived from iodine molecules (I2), and this liquid composition may further contain a substance derived from an iodine compound. The iodine compound is preferably at least one selected from 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.

[0032] The liquid composition may also contain a substance derived from a chlorine compound in addition to a substance derived from chlorine molecules (Cl2) as an oxidizing agent. The chlorine compound is preferably at least one selected from 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 also contain a substance derived from iodine molecules (I2), a substance derived from chlorine molecules (Cl2), a substance derived from an iodine compound, and a substance derived from a chlorine compound.

[0033] When the liquid composition contains a substance derived from a halide, the content of the substance derived from a halide may be 0.01 to 20 mass%, 0.1 to 18 mass%, 1.0 to 15 mass%, or 5.0 to 10 mass% relative to the total mass of the liquid composition. A liquid composition containing a substance derived from a halide in this range does not inhibit the adsorption of precious metals by the adsorbent.

[0034] (hydrophilic organic solvent) In the precious metal recovery method of the present disclosure, the liquid composition may or may not contain a hydrophilic organic solvent. In this specification, "organic solvent" refers to an organic compound that is liquid at room temperature, and may also be referred to as "organic solvent." Here, "liquid" refers to a state that is fluid at room temperature (15 to 35°C). More specifically, the organic solvent refers to an organic compound that is fluid at room temperature and normal pressure (e.g., 15 to 35°C, 1 atmosphere). "Hydrophilic organic solvent" refers to an organic solvent that is miscible with water or soluble in water.

[0035] The hydrophilic organic solvent contained in the liquid composition is preferably a polar solvent, and may be an aprotic polar solvent or a protic polar solvent.

[0036] From another perspective, the hydrophilic organic solvent may be an organic solvent having a heteroatom selected from the group consisting of a nitrogen atom (N), a sulfur atom (S), and an oxygen atom (O).

[0037] Specific examples of the hydrophilic organic solvent include N-methylpyrrolidone, acetonitrile, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetone, tetrahydrofuran, propylene carbonate, methanol, ethanol, 2-propanol, n-butanol, tert-butyl alcohol, benzyl alcohol, etc. When the liquid composition contains a hydrophilic organic solvent, from the viewpoint of easily achieving the effects of the present disclosure, a preferred hydrophilic organic solvent is at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

[0038] When the liquid composition contains a hydrophilic organic solvent, the precious metal is more efficiently adsorbed by the adsorbent described below, and therefore the content of the hydrophilic organic solvent may be more than 0 mass% and less than 15 mass%, or may be 1 mass% to 12 mass%, or may be 5 mass% to 10 mass%, relative to the entire liquid composition.

[0039] (Method of producing liquid composition for adsorption) In one embodiment, the liquid composition for adsorption of the present disclosure is produced by adding a material containing a precious metal to a metal solution containing water and an oxidizing agent, and dissolving the precious metal in the material in the metal solution. The oxidizing agent in the metal solution contributes to the dissolution of the precious metal. The oxidizing agent is altered or changed during the process of dissolving the precious metal, thereby generating an oxidizing agent-derived substance. This results in a liquid composition containing the dissolved precious metal, water, and an oxidizing agent-derived substance. In other words, the method for producing the liquid composition for adsorption of the present disclosure includes dissolving a precious metal in a metal solution containing water and an oxidizing agent to obtain the liquid composition for adsorption. The amount of water in this liquid composition for adsorption is 85% by mass or more based on the total amount of the liquid composition for adsorption.

[0040] Materials containing precious metals include, for example, used electronic and electronic devices, their components, scraps from decorative items, waste catalysts, etc. In addition, semiconductors that use gold as the material for bonding wires to connect the electrodes of IC chips to lead frames can be used as materials containing gold.

[0041] The oxidizing agent contained in the metal-dissolving solution can be any of the oxidizing agents described above for the liquid composition. Preferred oxidizing agents are halogen molecules (X, where X = I, Br, Cl, etc.), such as iodine molecules (I), bromine molecules (Br), and chlorine molecules (Cl). Iodine molecules (I) and / or chlorine molecules (Cl) are more preferred, and iodine molecules (I) are even more preferred.

[0042] The content of the oxidizing agent in the metal-dissolving liquid may be 0.01% by mass to 20% by mass, 0.01% by mass to 18% by mass, 0.01% by mass to 15% by mass, 0.01% by mass to 10% by mass, 0.1% by mass to 20% by mass, 0.1% by mass to 18% by mass, 0.1% by mass to 15% by mass, 0.1% by mass to 10% by mass, 1.0% by mass to 20% by mass, 1.0% by mass to 18% by mass, 1.0% by mass to 15% by mass, or 1.0% by mass to 10% by mass, based on the total amount of the metal-dissolving liquid. A metal-dissolving liquid containing an oxidizing agent in this range is easy to use for dissolving precious metals and has excellent solubility.

[0043] The metal dissolving solution may contain a halide together with halogen molecules (X2, X = I, Br, Cl, etc.). In a metal dissolving solution containing a halide, halogens consumed as oxidizing agents when dissolving precious metals are replenished. This maintains the solubility of precious metals. The halides described above for the liquid composition can be used. A halide containing the same halogen as the halogen molecule serving as the oxidizing agent is preferred. In other words, a preferred metal dissolving solution contains one or more halogen molecules selected from the group consisting of iodine molecules (I2), bromine molecules (Br2), and chlorine molecules (Cl2) as an oxidizing agent, and further contains a halide containing the same halogen as the oxidizing agent. The halides described above for the liquid composition can be used.

[0044] For example, when the metal-dissolving solution contains iodine molecules (I2) as an oxidizing agent, the metal-dissolving solution preferably further contains an iodine compound. The iodine compounds described above for the liquid composition can be used. A preferred iodine compound is at least one selected from the group consisting of alkali metal iodides, alkaline earth metal iodides, and ammonium iodides. Furthermore, when the metal-dissolving solution contains chlorine molecules (Cl2) as an oxidizing agent, the metal-dissolving solution preferably further contains a chlorine compound. The chlorine compounds described above for the liquid composition can be used. A preferred chlorine compound is at least one selected from the group consisting of alkali metal chlorides, alkaline earth metal chlorides, and ammonium chlorides. The metal-dissolving solution may contain iodine molecules (I2) and chlorine molecules (Cl2) as oxidizing agents, and may further contain an iodine compound and a chlorine compound.

[0045] When the metal-dissolving liquid contains a halide, the content of the halide may be 0.01% by mass to 20% by mass, 0.01% by mass to 18% by mass, 0.01% by mass to 15% by mass, 0.01% by mass to 10% by mass, 0.1% by mass to 20% by mass, 0.1% by mass to 18% by mass, 0.1% by mass to 15% by mass, 0.1% by mass to 10% by mass, 1.0% by mass to 20% by mass, 1.0% by mass to 18% by mass, 1.0% by mass to 15% by mass, 1.0% by mass to 10% by mass, 5.0% by mass to 20% by mass, 5.0% by mass to 18% by mass, 5.0% by mass to 15% by mass, or 5.0% by mass to 10% by mass, relative to the entire metal-dissolving liquid. A metal dissolving solution containing a halide in this range maintains excellent noble metal solubility for a long period of time.

[0046] From the viewpoint of excellent solubility of precious metals, the amount of water in the metal-dissolved liquid may be more than 0 mass% and not more than 85 mass%, may be 1 mass% to 80 mass% or less, may be 5 mass% to 70 mass%, or may be 10 mass% to 55 mass%, based on the total mass of the metal-dissolved liquid.

[0047] The metal-dissolving solution may or may not further contain a hydrophilic organic solvent. When the metal-dissolving solution contains a hydrophilic organic solvent, the hydrophilic organic solvents described above for the liquid composition can be used. The preferred hydrophilic organic solvent is at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

[0048] When the metal-dissolving liquid contains a hydrophilic organic solvent, the content of the hydrophilic organic solvent in the metal-dissolving liquid may be more than 0 mass% and less than 99 mass%, may be 1 mass% to 98 mass%, may be 5 mass% to 97 mass%, may be 5 mass% to 95 mass%, may be 5 mass% to 90 mass%, may be 5 mass% to 80 mass%, may be 10 mass% to 98 mass%, may be 10 mass% to 97 mass%, may be 10 mass% to 95 mass%, may be 10 mass% to 90 mass%, may be 10 mass% to 80 mass%, or may be 20 mass% to 98 mass%. The hydrophilic organic solvent content may be 20% to 97% by mass, 20% to 95% by mass, 20% to 90% by mass, 20% to 80% by mass, 25% to 98% by mass, 25% to 97% by mass, 25% to 95% by mass, 25% to 90% by mass, 25% to 80% by mass, 30% to 98% by mass, 30% to 97% by mass, 30% to 95% by mass, 30% to 90% by mass, or 30% to 80% by mass. A metal-dissolving liquid containing a hydrophilic organic solvent in this range has excellent solubility for precious metals.

[0049] In another embodiment, a liquid composition containing 85 mass% or more of water based on the total liquid composition may be produced by adding water to a precious metal-containing liquid containing an oxidant-derived substance and a precious metal. This precious metal-containing liquid may be obtained by adding a material containing a precious metal to a metal-dissolving liquid containing an oxidant and dissolving the precious metal in the material in the metal-dissolving liquid. In other words, the method for producing a liquid composition for adsorption of the present disclosure includes adding water to a precious metal-containing liquid containing an oxidant-derived substance to obtain the liquid composition for adsorption. In more detail, the method for producing a liquid composition for adsorption of the present disclosure includes dissolving a precious metal in a metal-dissolving liquid containing an oxidant to obtain a precious metal-containing liquid containing an oxidant-derived substance, and adding water to the precious metal-containing liquid to obtain the liquid composition for adsorption.

[0050] Examples of oxidant-derived substances contained in the precious metal-containing liquid include the oxidant-derived substances described above for the liquid composition. Preferred oxidant-derived substances are substances derived from halogen molecules (X, where X=I, Br, Cl, etc.), such as iodine molecules (I), bromine molecules (Br), and chlorine molecules (Cl). Substances derived from iodine molecules (I) and / or chlorine molecules (Cl) are more preferred, and substances derived from iodine molecules (I) are even more preferred.

[0051] The content of the oxidizing agent-derived substance in the precious metal-containing liquid may be 0.01 mass% to 20 mass%, 0.1 mass% to 18 mass%, 0.5 mass% to 15 mass%, or 1.0 mass% to 10 mass% relative to the entire precious metal-containing liquid.

[0052] The noble metal-containing liquid may contain a substance derived from a halide as described above for the liquid composition, in addition to a substance derived from a halogen molecule (X, where X = I, Br, Cl, etc.). Preferably, the noble metal-containing liquid contains, as an oxidizing agent-derived substance, a substance derived from an iodine molecule (I) and / or a substance derived from a chlorine molecule (Cl), and further contains a substance derived from a halide containing the same halogen as the oxidizing agent-derived substance (i.e., an iodine compound and / or a chlorine compound). For example, the noble metal-containing liquid contains a substance derived from an iodine compound as well as a substance derived from an iodine molecule (I). The iodine compounds described above for the liquid composition can be used. A preferred iodine compound is at least one selected from the group consisting of alkali metal iodides, alkaline earth metal iodides, and ammonium iodide. Furthermore, the noble metal-containing liquid may further contain a substance derived from a chlorine compound as well as a substance derived from a chlorine molecule (Cl). The chlorine compounds described above for the liquid composition can be used. The preferred chlorine compound is at least one selected from the group consisting of alkali metal chlorides, alkaline earth metal chlorides, and ammonium chlorides. The noble metal-containing liquid may contain a substance derived from iodine molecules (I2) and a substance derived from chlorine molecules (Cl2), and may further contain a substance derived from an iodine compound and a substance derived from a chlorine compound.

[0053] When the precious metal-containing liquid contains a substance derived from a halide, the content of the substance derived from the halide may be 0.01% by mass to 20% by mass, 0.1% by mass to 18% by mass, 1.0% by mass to 15% by mass, or 5.0% by mass to 10% by mass, relative to the entire precious metal-containing liquid.

[0054] The precious metal-containing liquid may or may not contain water. When the precious metal-containing liquid contains water, the amount of water in the precious metal-containing liquid may be more than 0 mass % and 85 mass % or less, 1 mass % to 80 mass % or less, 5 mass % to 70 mass %, or 10 mass % to 55 mass % with respect to the entire precious metal-containing liquid.

[0055] The noble metal-containing liquid may or may not further contain a hydrophilic organic solvent. When the noble metal-containing liquid contains a hydrophilic organic solvent, the hydrophilic organic solvents described above for the liquid composition can be used. The preferred hydrophilic organic solvent is at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

[0056] When the precious metal-containing liquid contains a hydrophilic organic solvent, the content of the hydrophilic organic solvent in the precious metal-containing liquid may be greater than 0 mass% and less than 99 mass%, may be 1 mass% to 98 mass%, may be 5 mass% to 97 mass%, may be 10 mass% to 95 mass%, may be 20 mass% to 90 mass%, or may be 25 mass% to 80 mass%, relative to the entire precious metal-containing liquid.

[0057] (adsorbent) In the precious metal recovery method of the present disclosure, a liquid composition containing dissolved precious metals is contacted with an adsorbent, thereby allowing the dissolved precious metals in the liquid composition to be adsorbed onto the adsorbent. For example, the liquid composition may be contacted with the adsorbent by adding the adsorbent to the liquid composition and mixing, or by passing the liquid composition through a cartridge (e.g., a column) filled with the adsorbent. In other words, the adsorbent of the present disclosure and a cartridge containing the adsorbent are used in the precious metal recovery method described above. Here, the term "cartridge" refers to a container that can accommodate the adsorbent and through which a liquid can pass. A column is typically a cylindrical container. In other words, the adsorbent according to the present disclosure is a precious metal recovery adsorbent that adsorbs the precious metals in a liquid composition containing the precious metals upon contact with the liquid composition, wherein the liquid composition further contains water and an oxidant-derived substance, and the amount of water in the liquid composition is 85% by mass or more relative to the total amount of the liquid composition. All of the dissolved precious metals in the liquid composition may be adsorbed by the adsorbent, or a portion of the precious metals in the liquid composition may be adsorbed by the adsorbent, or the precious metals that are not adsorbed by the adsorbent may remain in the liquid composition.

[0058] The type of adsorbent is not particularly limited, and any adsorbent capable of adsorbing precious metals in the liquid composition described above can be appropriately selected and used. An adsorbent capable of selectively adsorbing gold is preferred. In the present disclosure, the adsorbent is typically solid, and preferably porous. Adsorbents in various shapes, such as powder, granules, and fibers, can be used.

[0059] From the viewpoint of high adsorption efficiency of precious metals, the adsorbent material is preferably at least one selected from the group consisting of cellulose derivatives, ion exchange resins, and activated carbon, and more preferably cellulose derivatives.

[0060] In this specification, "cellulose derivative" is defined as a general term for compounds in which various substituents have been introduced into at least some of the hydroxyl groups in cellulose. Preferred cellulose derivatives are cellulose esters in which at least some of the hydroxyl groups in cellulose have been esterified. Cellulose esters with a total degree of substitution of 0.8 to 2.9 are more preferred. From the viewpoint of being able to selectively adsorb gold, the total degree of substitution of the cellulose ester may be 0.8 to 2.9, may be 1.0 to 2.9, may be 1.2 to 2.9, may be 1.5 to 2.9, may be 1.8 to 2.9, may be 2.0 to 2.9, may be 2.3 to 2.9, may be 0.8 to 2.8, may be 1.0 to 2.8, may be 1.2 to 2.8, may be 1.5 to 2.8, may be 1.8 to 2.8, may be 2.0 to 2.8, may be 2.3 to 2.8, may be 0.8 to 2.7, may be 1.0 to 2.7, may be 1.2 to 2.7, may be 1.5 to 2.7, may be 1.8 to 2.7, may be 2.0 to 2.7, or may be 2.3 to 2.7. The total degree of substitution of a cellulose ester is the sum of the degrees of substitution at the 2-, 3-, and 6-positions of the glucose ring of the cellulose ester, and can be measured, for example, by NMR according to the method of Tezuka (Tezuka, Carbonydr. Res. 273, 83 (1995)).

[0061] Preferably, the cellulose derivative is cellulose acylate in which at least a portion of the hydroxyl groups in cellulose are substituted with acyl groups having a carbon number of 2 to 40. The number of carbon atoms in the acyl groups of the cellulose ester may be 2 to 30, 2 to 20, 2 to 10, 2 to 5, or 2 to 3. From the viewpoint of being able to selectively adsorb gold, the degree of substitution with acyl groups of cellulose acylate may be 0.8 to 2.9, may be 1.0 to 2.9, may be 1.2 to 2.9, may be 1.5 to 2.9, may be 1.8 to 2.9, may be 2.0 to 2.9, may be 2.3 to 2.9, may be 0.8 to 2.8, may be 1.0 to 2.8, may be 1.2 to 2.8, may be 1.5 to 2.8, may be 1.8 to 2.8, may be 2.0 to 2.8, may be 2.3 to 2.8, may be 0.8 to 2.7, may be 1.0 to 2.7, may be 1.2 to 2.7, may be 1.5 to 2.7, may be 1.8 to 2.7, may be 2.0 to 2.7, or may be 2.3 to 2.7. The degree of substitution by acyl groups in cellulose acylate is the sum of the degrees of acyl substitution at the 2-, 3- and 6-positions of the glucose ring of the cellulose ester, and can be determined in the same manner as in the measurement of the total degree of substitution of the cellulose derivative described above.

[0062] Preferably, the cellulose derivative is cellulose acetate in which at least a portion of the hydroxyl groups in cellulose has been substituted with acetyl groups, and more preferably, cellulose acetate having an acetyl substitution degree of 0.8 or more and 2.9 or less. From the viewpoint of being able to selectively adsorb gold, the degree of acetyl substitution of cellulose acetate may be 0.8 to 2.9, may be 1.0 to 2.9, may be 1.2 to 2.9, may be 1.5 to 2.9, may be 1.8 to 2.9, may be 2.0 to 2.9, may be 2.3 to 2.9, may be 0.8 to 2.8, may be 1.0 to 2.8, may be 1.2 to 2.8, may be 1.5 to 2.8, may be 1.8 to 2.8, may be 2.0 to 2.8, may be 2.3 to 2.8, may be 0.8 to 2.7, may be 1.0 to 2.7, may be 1.2 to 2.7, may be 1.5 to 2.7, may be 1.8 to 2.7, may be 2.0 to 2.7, or may be 2.3 to 2.7. The degree of acetyl substitution of a cellulose ester is the sum of the degrees of acetyl substitution at the 2-, 3- and 6-positions of the glucose ring of the cellulose ester, and can be determined in the same manner as in the measurement method described above for the total degree of substitution of a cellulose derivative.

[0063] When the material of the adsorbent is cellulose acetate, the cellulose acetate may contain other substituents besides acetyl groups, as long as the effects of the present disclosure are obtained. Examples of such other substituents include acyl groups such as propionyl, butyryl, pentanoyl (valeryl), hexanoyl, heptanoyl, octanoyl, nonanoyl, undecanoyl, dodecanoyl, tridecanoyl, tetradecanoyl (myristoyl), pentadecanoyl, hexadecanoyl, heptadecanoyl, and octadecanoyl (stearoyl).

[0064] In this specification, the term "ion exchange resin" refers to a resin made of a crosslinked polymer having ion exchange groups and containing counterions exchangeable with the target ions. The type of ion exchange resin may be selected appropriately depending on the type of target ions, as long as it is capable of ion exchange in the presence of an organic solvent. Examples of ion exchange resins include polyolefins, (meth)acrylic resins, styrene resins, polyacetals, polyesters, polycarbonates, polyamides, polyamideimides, polyimides, polyethers, polyetherimides, polyetherketones, polyetheretherketones, polysulfones, polyethersulfones, polyphenylene sulfides, and fluororesins, each of which has an ion exchange group. 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. Anion exchange resins capable of exchanging negative ions are particularly preferred.

[0065] In this specification, "activated carbon" is defined as a material that is substantially composed of carbon and has a plurality of pores on its surface. The type of activated carbon is not particularly limited, and commercially available known activated carbon can be appropriately selected and used regardless of origin, activation method, shape, etc. For example, activated carbon of mineral origin, activated carbon of plant origin, activated carbon of resin origin, steam-activated activated carbon, or chemically activated activated carbon can be appropriately selected. The shape of the activated carbon can be appropriately selected from powder, granular, crushed, fibrous, honeycomb, etc.

[0066] When activated carbon is selected as the adsorbent material, the specific surface area of the activated carbon should be 200 to 3500 m 2 / g is preferred, and 400 to 2000m 2 / g is more preferable, and 800 to 2000m 2 The total pore volume of the 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.

[0067] The amount of adsorbent added can be appropriately selected depending on the type of adsorbent. From the viewpoint of efficiently adsorbing gold, the amount of adsorbent added may 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. The concentration may be 5 g / L to 300 g / L, 5 g / L to 200 g / L, 5 g / L to 100 g / L, 10 g / L to 1000 g / L, 10 g / L to 500 g / L, 10 g / L to 300 g / L, 10 g / L to 200 g / L, 10 g / L to 100 g / L, 15 g / L to 1000 g / L, 15 g / L to 500 g / L, 15 g / L to 300 g / L, 15 g / L to 200 g / L, or 15 g / L to 100 g / L.

[0068] In the precious metal recovery method of the present disclosure, by contacting an adsorbent with a liquid composition, in principle, the dissolved precious metals in the liquid composition are preferentially adsorbed onto the adsorbent. However, in rare cases, substances other than precious metals derived from oxidizing agents or halides (e.g., halogen ions such as chloride ions, halogen molecules, etc.) may be adsorbed. In this case, the adsorption of substances other than precious metals in the liquid composition can be suppressed by adsorbing the target substance (oxidizing agent-derived substance or halide-derived substance) onto the adsorbent before contacting the adsorbent with the liquid composition. In other words, the precious metal recovery method of the present disclosure may further include a step of adsorbing the oxidizing agent-derived substance onto the adsorbent, or a step of adsorbing the oxidizing agent-derived substance and / or the halide-derived substance onto the adsorbent before contacting the liquid composition with the adsorbent.

[0069] By contacting the liquid composition with an adsorbent, a precious metal-containing adsorbent is obtained in which the precious metal in the liquid composition is adsorbed. By separating this precious metal-containing adsorbent from the liquid composition, the precious metal adsorbed by the precious metal-containing adsorbent can be recovered.

[0070] The method for separating the precious metal-containing adsorbent is not particularly limited, and any common solid-liquid separation method can be used, such as filtration, centrifugation, and sedimentation.

[0071] As a method for recovering precious metals from a precious metal-containing adsorbent, for example, a desorption liquid may be used to liberate the precious metals from the precious metal-containing adsorbent and recover the precious metals eluted into the desorption liquid, or the precious metal-containing adsorbent may be incinerated and the precious metals recovered as an incineration residue. Examples of methods using a desorption liquid include a method in which the desorption liquid is passed through a precious metal-containing adsorbent packed in a cartridge (e.g., a column), and a method in which the precious metal-containing adsorbent is introduced into the desorption liquid and stirred.

[0072] The type of desorption liquid can be selected depending on the type of adsorbent. For example, in the case of an adsorbent made of a cellulose derivative, preferred desorption liquids are water, an aqueous sodium chloride solution, etc.

[0073] (Application) The precious metal recovery method and liquid adsorption composition disclosed herein are used for recovering precious metals from used electrical and electronic devices using an adsorbent, extracting precious metals from ores, etc. They can also be applied to recovering precious metals from etching solutions used in semiconductor manufacturing processes. [Example]

[0074] The present disclosure will be specifically described below using examples, but the technical scope of the present disclosure is not limited to these examples. Unless otherwise specified, the test temperature was room temperature.

[0075] [Example 1] (Preparation of metal solution) Metal-dissolved solution (1) was prepared by mixing N-methylpyrrolidone (Kanto Chemical Co., Ltd., 38% by weight), iodine (I2, Kanto Chemical Co., Ltd., 3% by weight), ammonium iodide (Fujifilm Wako Pure Chemical Industries, Ltd., 7% by weight), and water (52% by weight). The composition of this metal-dissolved solution (1) is shown in Table 1 below.

[0076] A gold wire (φ=0.20 mm, purity 99.95%, manufactured by Nilaco Corporation) was added to the obtained metal-dissolved solution (1) and dissolved therein, and then 900 parts by mass of water was added to 100 parts by mass of the metal-dissolved solution (1) to obtain an adsorption liquid composition (1) with a water content of 95.2 wt.% and a gold concentration of 89 ppm. The water content and dissolved gold concentration of this adsorption liquid composition (1) are shown in Table 1 below as "Water (in adsorption liquid composition)" and "Initial gold concentration (M1)," respectively.

[0077] (Adsorption test) Adsorbent A (cellulose acetate, acetyl substitution degree 2.5) was added to the resulting liquid composition for adsorption (1) to adsorb the gold dissolved in the liquid composition for adsorption (1). The amount of adsorbent A added was 2 g (g / L) relative to the liquid composition for adsorption (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 measured. To measure the gold concentration, an inductively coupled plasma (ICP) emission spectrum was measured using an inductively coupled plasma optical emission spectrometer (trade name "Agilent 5110" manufactured by Agilent Technologies). The gold concentration before adsorption was defined as M1 (ppm) and the gold concentration after adsorption as M2 (ppm), and the gold adsorption rate X (%) by the adsorbent was calculated using the following formula. The results are shown in Table 1 below as "Gold Adsorption Rate (%)." X(wt%)=(M1(ppm)-M2(ppm)) / M1(ppm)×100

[0078] [Example 2] An adsorption test was carried out in the same manner as in Example 1, except that the amount of adsorbent in the adsorption test and the gold concentration in the liquid composition for adsorption were changed as shown in Table 1 below. The composition of the metal-dissolved solution and the results of the adsorption test are shown in Table 1 below. The water content and dissolved gold concentration of the liquid composition for adsorption (2) are also shown in Table 1 below as "Water (in liquid composition for adsorption)" and "Initial gold concentration (M1)", respectively.

[0079] [Example 3-4] An adsorption test was carried out in the same manner as in Example 1, except that the composition of the metal-dissolving solution was changed to that shown in Table 1 below. The composition of the metal-dissolving solution and the results of the adsorption test are shown in Table 1 below. The water content and dissolved gold concentration of the adsorption liquid compositions (3) and (4) are also shown in Table 1 below as "Water (in the adsorption liquid composition)" and "Initial gold concentration (M1)", respectively.

[0080] [Example 5] Iodine (I2, manufactured by Kanto Chemical Co., Inc., 5% by weight), ammonium iodide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% by weight), and water (85% by weight) were mixed to prepare a metal solution (5). The composition of this metal solution (5) is shown in Table 1 below.

[0081] A gold wire (φ=0.20 mm, purity 99.95%, manufactured by Nilaco Corporation) was added to and dissolved in the resulting metal-dissolved solution (5), yielding a liquid composition for adsorption (5) with a water content of 85 wt. % and a gold concentration of 190 ppm. The water content and dissolved gold concentration of this liquid composition for adsorption (5) are shown in Table 1 below as "Water (in liquid composition for adsorption)" and "Initial gold concentration (M1)," respectively.

[0082] Adsorbent A (cellulose acetate, degree of acetyl substitution: 2.5) was added to the resulting liquid composition for adsorption (5) to adsorb the gold dissolved in the liquid composition for adsorption (5). The amount of adsorbent A added was 20 g (g / L) relative to the amount of 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 using the method described above in Example 1. The results are shown in Table 1 below as "gold adsorption rate (%)."

[0083] [Comparative Example 1] A metal dissolving solution (C1) was prepared by mixing N-methylpyrrolidone (Kanto Chemical Co., Ltd., 38% by weight), iodine (I2, Kanto Chemical Co., Ltd., 3% by weight), ammonium iodide (Fujifilm Wako Pure Chemical Industries, Ltd., 7% by weight), and water (52% by weight). The composition of this metal dissolving solution is shown in Table 1 below. A gold wire (φ=0.20 mm, purity 99.95%, manufactured by Nilaco Corporation) was added to and dissolved in the resulting metal-dissolved solution (C1), yielding a liquid composition for adsorption (C1) with a water content of 52 wt.% and a gold concentration of 1600 ppm. The water content and dissolved gold concentration of this liquid composition for adsorption (C1) are shown in Table 1 below as "Water (in liquid composition for adsorption)" and "Initial gold concentration (M1)," respectively. Except for using the obtained liquid composition for adsorption (C1), an adsorption test was carried out in the same manner as in Example 1. The results obtained are shown in Table 1 below. In the adsorption test of Comparative Example 1, gold could not be recovered by the adsorbent.

[0084] [Comparative Example 2-3] Gold was dissolved in a metal-dissolving solution in the same manner as in Comparative Example 1, and then water was added in the amounts shown in Table 1 below to 100 parts by mass of the metal-dissolving solution to obtain 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. Adsorption tests were carried out in the same manner as in Comparative Example 1, except that adsorption liquid compositions (C2) and (C3) were used instead of adsorption liquid composition (C1). The compositions of the metal-dissolving solutions and the results of the adsorption tests are shown in Table 1 below. The water content and dissolved gold concentration of adsorption liquid compositions (C2) and (C3) are also shown in Table 1 below as "Water (in adsorption liquid composition)" and "Initial gold concentration (M1)", respectively. In all of Comparative Examples 2 to 3, gold could not be recovered by the adsorbent.

[0085] [Table 1]

[0086] As shown in Table 1, in the examples in which the amount of water in the adsorption liquid composition was 85% by mass or more, the dissolved precious metals could be efficiently recovered by the adsorbent. On the other hand, in the comparative examples in which the amount of water was less than 85% by mass, the dissolved precious metals could not be recovered by the adsorbent. The superiority of the present disclosure is clear from these evaluation results.

[0087] [Disclosure items] Each of the following sections discloses a preferred embodiment.

[0088] [Item 1] contacting a liquid composition containing a precious metal with an adsorbent to adsorb the precious metal in the liquid composition onto the adsorbent, thereby recovering the precious metal; the liquid composition further comprises water and an oxidizing agent-derived substance; A method for recovering precious metals, wherein the amount of water in the liquid composition is 85 mass % or more based on the total amount of the liquid composition. [Item 2] 2. The method for recovering precious metals according to Item 1, further comprising adjusting the amount of water in the liquid composition to 85% by mass or more of the total liquid composition before contact with the adsorbent. [Item 3] 3. The method for recovering a precious metal according to item 1 or 2, wherein the precious metal is gold. [Item 4] 4. The method for recovering precious metals according to any one of items 1 to 3, wherein the oxidizing agent-derived substance is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2). [Item 5] the oxidizing agent-derived substance is a substance derived from an iodine molecule (I2) and / or a substance derived from a chlorine molecule (Cl2), 5. The method for recovering precious metals according to any one of items 1 to 4, wherein the liquid composition further contains a substance derived from a halide containing the same halogen as the oxidizing agent-derived substance. [Item 6] 6. The method for recovering precious metals according to item 5, wherein the halide is at least one selected from the group consisting of alkali metal halides, alkaline earth metal halides, and ammonium halides. [Item 7] 7. The method for recovering precious metals according to any one of items 1 to 6, wherein the material of the adsorbent is at least one selected from the group consisting of cellulose derivatives, ion exchange resins, and activated carbon. [Item 8] 8. The method for recovering precious metals according to item 7, wherein the cellulose derivative is a cellulose ester having a total degree of substitution of 0.8 or more and 2.9 or less. [Item 9] Item 9. The method for recovering precious metals according to Item 7 or 8, wherein the cellulose derivative is cellulose acetate in which at least a portion of the hydroxyl groups in cellulose are substituted with acetyl groups. [Item 10] 10. 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. [Item 11] Item 11. The method for recovering precious metals according to Item 10, wherein the hydrophilic organic solvent is an organic solvent having a heteroatom. [Item 12] Item 12. The method for recovering precious metals according to Item 10 or 11, wherein the hydrophilic organic solvent is a polar solvent. [Item 13] 13. The method for recovering a precious metal 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. [Item 14] 14. An adsorbent used in the method for recovering precious metals according to any one of items 1 to 13. [Item 15] 15. A cartridge comprising the adsorbent material according to item 14. [Item 16] A liquid adsorption composition used in the method for recovering precious metals according to any one of items 1 to 13, The liquid composition for adsorption contains water, an oxidant-derived substance, and a precious metal; The amount of water is 85% by mass or more based on the total amount of the liquid composition for adsorption. [Item 17] Item 17. The liquid adsorption composition according to item 16, wherein the noble metal is gold. [Item 18] Item 18. The liquid composition for adsorption according to Item 16 or 17, wherein the oxidizing agent-derived substance is a substance derived from iodine molecules (I2) and / or a substance derived from chlorine molecules (Cl2). [Item 19] the oxidizing agent-derived substance is a substance derived from an iodine molecule (I2) and / or a substance derived from a chlorine molecule (Cl2), the liquid composition for adsorption further contains a substance derived from a halide containing the same halogen as the oxidizing agent-derived substance, 19. The liquid composition for adsorption according to any one of items 16 to 18, wherein the halide is at least one selected from the group consisting of alkali metal halides, alkaline earth metal halides, and ammonium halides. [Item 20] further comprising a hydrophilic organic solvent; 20. The liquid composition for adsorption according to any one of items 16 to 19, wherein the hydrophilic organic solvent is at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol. [Item 21] The method comprises dissolving a precious metal in a metal dissolving solution containing water and an oxidizing agent to obtain a liquid composition for adsorption, 21. The method for producing a liquid composition for adsorption according to any one of items 16 to 20, wherein the amount of water in the liquid composition for adsorption is 85% by mass or more based on the total amount of the liquid composition for adsorption. [Item 22] The method includes adding water to a precious metal-containing liquid containing an oxidizing agent-derived substance and a precious metal to obtain a liquid composition for adsorption, 21. The method for producing a liquid composition for adsorption according to any one of items 16 to 20, wherein the amount of water in the liquid composition for adsorption is 85% by mass or more based on the total amount of the liquid composition for adsorption. [Industrial Applicability]

[0089] The recovery method described above can be applied to the recovery of precious metals from etching solutions in addition to the recovery of precious metals from used equipment.

Claims

1. contacting a liquid composition containing a precious metal with an adsorbent to adsorb the precious metal in the liquid composition onto the adsorbent, thereby recovering the precious metal; the liquid composition further comprises water and an oxidizing agent-derived substance; A method for recovering precious metals, wherein the amount of water in the liquid composition is 85 mass % or more based on the total amount of the liquid composition.

2. The method for recovering precious metals described in claim 1, further comprising adjusting the amount of water in the liquid composition to 85 mass% or more of the entire liquid composition before contact with the adsorbent.

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

4. The oxidizing agent-derived substance is an iodine molecule (I ２ ) and / or chlorine molecules (Cl ２ 2. The method for recovering precious metals according to claim 1, wherein the material is derived from a process for the recovery of precious metals.

5. The oxidizing agent-derived substance is iodine molecule (I ２ ) and / or chlorine molecules (Cl ２ ) is a substance derived from 2. The method for recovering precious metals according to claim 1, wherein the liquid composition further contains a substance derived from a halide containing the same halogen as the substance derived from the oxidizing agent.

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

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

9. 8. The method for recovering precious metals according to claim 7, wherein the cellulose derivative is cellulose acetate in which at least a portion of the hydroxyl groups in cellulose have been substituted with acetyl groups.

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

11. 11. The method for recovering precious metals according to claim 10, wherein the hydrophilic organic solvent is an organic solvent having a heteroatom.

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

13. 11. 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 used in the method for recovering precious metals according to claim 1.

15. A cartridge comprising the adsorbent material of claim 14.

16. A liquid adsorption composition used in the method for recovering precious metals according to claim 1, The liquid composition for adsorption contains water, an oxidant-derived substance, and a precious metal; The amount of water is 85% by mass or more based on the total amount of the liquid composition for adsorption.

17. 17. The liquid adsorption composition according to claim 16, wherein said noble metal is gold.

18. The oxidizing agent-derived substance is iodine molecule (I ２ ) and / or chlorine molecules (Cl ２ 17. The liquid composition for adsorption according to claim 16, which is a substance derived from

19. The oxidizing agent-derived substance is iodine molecule (I ２ ) and / or chlorine molecules (Cl ２ ) is a substance derived from the liquid composition for adsorption further contains a substance derived from a halide containing the same halogen as the oxidizing agent-derived substance, 17. The liquid composition for adsorption according to claim 16, wherein the halide is at least one selected from the group consisting of alkali metal halides, alkaline earth metal halides, and ammonium halides.

20. further comprising a hydrophilic organic solvent; 17. The liquid composition for adsorption according to claim 16, wherein the hydrophilic organic solvent is at least one selected from the group consisting of N-methylpyrrolidone, acetonitrile, and methanol.

21. The method comprises dissolving a precious metal in a metal dissolving solution containing water and an oxidizing agent to obtain a liquid composition for adsorption, The method for producing a liquid composition for adsorption according to claim 16, wherein the amount of water in the liquid composition for adsorption is 85 mass % or more based on the total amount of the liquid composition for adsorption.

22. The method includes adding water to a precious metal-containing liquid containing an oxidizing agent-derived substance and a precious metal to obtain a liquid composition for adsorption, The method for producing a liquid composition for adsorption according to claim 16, wherein the amount of water in the liquid composition for adsorption is 85 mass % or more based on the total amount of the liquid composition for adsorption.

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