Recovery kit, recovery method, and recovery device for noble metal

Abstract

Provided is a noble metal recovery kit capable of easily recovering a high-purity noble metal from a metal secondary resource in an energy-saving manner. The noble metal recovery kit according to the present disclosure is a kit for recovering a noble metal (M), and includes a noble metal solution, a diluent, and an adsorbent. The precious metal dissolving solution comprises hydrochloric acid and nitric acid, and the molar ratio of hydrochloric acid to nitric acid is 2-6. The dilution solution is a solution obtained by diluting a noble metal solution obtained by dissolving a noble metal (M) in the noble metal solution, and the concentration of nitric acid in the noble metal solution is adjusted to 10 mol / L or more but less than 1.5 mol / L of the concentration of noble metal ions (Mn +) in the noble metal solution. Adsorption material: a member having the property of adsorbing noble metal ions (Mn +).

Description

Technical Field

[0001] The present disclosure relates to a precious metal recovery kit, a precious metal recovery method, and a precious metal recovery device. The present disclosure claims priority to Japanese Patent Application No. 2022-122630 filed in Japan on August 1, 2022, the contents of which are incorporated herein by reference. Background Art

[0002] Precious metals such as gold, platinum, and palladium are very expensive, but they are indispensable catalysts in electronic components, semiconductors, and automobile exhaust purification, and are extremely important substances in the most advanced fields such as liquid crystal glass and LEDs.

[0003] Electrical and electronic equipment waste (e-waste) contains a large amount of precious metals, sometimes 10 times more than the amount contained in ore, which is called secondary metal resources. In addition, it is required to separate / recover precious metals from secondary metal resources cheaply and easily and reuse them.

[0004] Patent Document 1 records that aqua regia is used to dissolve metal secondary resources to obtain a gold ion solution, and the obtained gold ion solution is subjected to extraction treatment with dibutyl carbitol to obtain a gold-containing organic phase. In addition, it is recorded that if nitrate ions are present in the gold ion solution, nitrates of metals other than gold such as tin, platinum, palladium, etc. are easily mixed into the gold-containing organic phase, and the purity of the recovered gold can be reduced, so it is preferably completely free of nitrate ions. However, in order to remove nitrate ions, operations such as concentration need to be repeatedly performed, and there is a problem of needing labor and a large amount of heat energy.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-132552 Summary of the invention

[0008] Problems to be solved by the invention

[0009] Therefore, an object of the present disclosure is to provide a precious metal recovery kit that can energy-save and easily recover high-purity precious metals from secondary metal resources.

[0010] Another object of the present disclosure is to provide a method for recovering precious metals which can save energy and easily recover high-purity precious metals from secondary metal resources.

[0011] Another object of the present disclosure is to provide a precious metal recovery device that can energy-savingly and simply recover high-purity precious metals from secondary metal resources.

[0012] Solutions for solving problems

[0013] The inventors of the present invention have conducted intensive research to solve the above technical problems and found that the precious metal ions (M) obtained by dissolving a precious metal in a precious metal solution such as aqua regia n+ ) of a noble metal solution, if its nitric acid concentration is adjusted to a specific range, it will have the ability to adsorb noble metal ions (M n+ ) is added to the adjusted solution, the function of the adsorbent material can be prevented from being damaged by nitric acid, and the noble metal ions (M n+ ) is efficiently adsorbed on the adsorbent; and when metals that are not the target of recovery (hereinafter sometimes referred to as "other metals") coexist with the target precious metal in the system, the other metals form nitrates and dissolve in the solution. In this case, if a nitrate adsorbent (M) is used n+ ) and other metal ions are not adsorbed by the adsorbent material, and the adsorbed noble metal ions (M n+ ) is separated from the solution, other metals can be easily separated / removed. n+ ) is separated from the solution and then subjected to reduction, calcination and other treatments to obtain a high-purity noble metal (M). The present disclosure is based on these findings.

[0014] That is, the present disclosure provides a precious metal recovery kit, which is a kit for recovering precious metals (M), comprising the following precious metal dissolving solution, the following diluent, and the following adsorbent.

[0015] Precious metal dissolving solution: contains hydrochloric acid and nitric acid, and the hydrochloric acid / nitric acid (molar ratio) is 2-6.

[0016] Dilution liquid: a liquid used to dilute a precious metal solution obtained by dissolving a precious metal (M) in the precious metal solution, and to adjust the nitric acid concentration in the precious metal solution to the precious metal ion (M) in the precious metal solution. n+ ) concentration and less than 1.5 mol / L.

[0017] Adsorption material: has the ability to adsorb precious metal ions (M n+ )'s properties.

[0018] The present disclosure also provides the precious metal recovery kit, wherein the precious metal dissolving solution is aqua regia.

[0019] The present disclosure also provides the precious metal recovery kit, wherein the adsorption material is an ester having a sugar skeleton.

[0020] The present disclosure also provides the precious metal recovery kit, wherein the adsorption material is a polysaccharide acylate.

[0021] The present disclosure also provides the precious metal recovery kit, wherein the adsorption material comprises a material having a function of adsorbing precious metal ions (M n+ ) of a separation membrane, a column filler or a box filler.

[0022] The present disclosure also provides the precious metal recovery kit, which is a kit for recovering precious metals (M) from secondary metal resources containing the precious metals (M).

[0023] The present disclosure also provides a method for recovering precious metals, which comprises the following steps: n + ) is in contact with the solution to make the noble metal ions (M n+ ) is adsorbed on the component, and the solution contains noble metal ions (M n+ ) and nitric acid, and the concentration of nitric acid is the noble metal ion (M n+ ) concentration and less than 1.5 mol / L.

[0024] The present disclosure also provides a precious metal recovery device, which comprises the following units: n + ) is in contact with the solution to make the noble metal ions (M n+ ) is adsorbed on the component, and the solution contains noble metal ions (M n+ ) and nitric acid, and the concentration of nitric acid is the noble metal ion (M n+ ) concentration and less than 1.5 mol / L.

[0025] Effects of the Invention

[0026] If the precious metal recovery kit of the present disclosure is used, high-purity precious metals (M) can be recovered from secondary metal resources in an energy-saving manner in a simple method without using a unit that requires a large amount of thermal energy. That is, the precious metal recovery kit has the effect of reducing the load on the environment and promoting the reuse of rare resources.

[0027] If the precious metal recovery method and precious metal recovery device disclosed in the present invention are used, it is possible to recover high-purity precious metals (M) from secondary metal resources in a simple and energy-saving manner without using units that require a large amount of thermal energy. That is, the precious metal recovery method and precious metal recovery device have the effect of reducing the load on the environment and promoting the reuse of rare resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic flow chart showing an example of the precious metal recovery method of the present disclosure.

[0029] Figure 2 : is a schematic flow chart showing another example of the precious metal recovery method of the present disclosure. DETAILED DESCRIPTION

[0030] [Precious Metal Recovery Kit]

[0031] The precious metal recovery kit disclosed in the present invention is a set of materials for recovering a specified precious metal (M), including the following precious metal solution (1), the following diluent (2) and the following adsorption material (3). In addition to these, the kit may also include other components as needed.

[0032] The noble metal dissolving solution (1) comprises hydrochloric acid and nitric acid, and the hydrochloric acid / nitric acid (molar ratio) is 2 to 6.

[0033] Dilution liquid (2): a liquid for diluting a precious metal solution obtained by dissolving a precious metal (M) in the precious metal solution, and adjusting the nitric acid concentration in the precious metal solution to the precious metal ion (M) in the precious metal solution. n+ ) concentration and less than 1.5 mol / L.

[0034] Adsorbent material (3): has the ability to adsorb precious metal ions (M n+ )'s properties.

[0035] The noble metal (M) disclosed herein includes zero-valent noble metal atoms and aggregates of the zero-valent noble metal atoms. In addition, the zero-valent noble metal atoms may be dispersed in a solution to form a colloid.

[0036] The noble metal (M) is, for example, one or more noble metals selected from gold, silver, platinum, copper, iridium, palladium, etc. The noble metal (M) dissolves to generate n-valent noble metal ions (M n+ ). The n is an integer greater than 1, and preferably an integer of 1 to 4.

[0037] By using the precious metal recovery kit, precious metals (M) (particularly gold) contained in secondary metal resources such as electrical / electronic equipment waste (e-waste) can be recovered easily and efficiently with energy saving.

[0038] The precious metal recovery kit is preferably used as a kit for recovering precious metals (M) contained in secondary metal resources, and is particularly preferably used as a kit for recovering gold contained in secondary metal resources.

[0039] (Precious metal solution (1))

[0040] The noble metal dissolving solution is a solution that has the function of dissolving the noble metal, and contains at least hydrochloric acid and nitric acid.

[0041] The molar ratio of hydrochloric acid to nitric acid (hydrochloric acid / nitric acid) contained in the noble metal solution is 2 to 6. In particular, from the perspective of excellent solubility of the noble metal, the upper limit of the molar ratio is preferably 5, more preferably 4.5, particularly preferably 4, most preferably 3.5, and particularly preferably 3. In addition, the lower limit of the molar ratio is preferably 2.5, and particularly preferably 3.

[0042] The concentrations of hydrochloric acid and nitric acid contained in the noble metal solution may be any concentration at which nitrosyl chloride (NOCl) and chlorine gas (Cl 2 ) that function to oxidize the noble metal are generated.

[0043] As the noble metal dissolving liquid, aqua regia is particularly preferred. Aqua regia is a mixed solution of concentrated hydrochloric acid and concentrated nitric acid, wherein the molar ratio of hydrochloric acid to nitric acid (hydrochloric acid / nitric acid) is 3.

[0044] In the precious metal recovery kit of the present disclosure, a precious metal dissolving solution is used to dissolve the precious metal (M). In this specification, the solution obtained in this way is referred to as a "precious metal solution".

[0045] The nitric acid concentration in the noble metal solution (the noble metal solution before adding the diluent (2)) is, for example, the noble metal ion (M n+ ) concentration is at least 60 mole times, preferably 600 to 600,000 mole times, and particularly preferably 6,000 to 60,000 mole times, in view of excellent solubility of the noble metal (M).

[0046] The concentration of hydrochloric acid in the noble metal solution (the noble metal solution before adding the diluent (2)) is, for example, the noble metal ion (M n+ ) concentration is 180 mole times or more, preferably 1,800 to 1,800,000 mole times, and particularly preferably 18,000 to 180,000 mole times, in view of excellent solubility of the noble metal (M).

[0047] (Dilution (2))

[0048] The diluent is a solution for diluting a noble metal solution obtained by dissolving a noble metal (M) in a noble metal solution (or a solution for adjusting the nitric acid concentration (preferably the nitric acid concentration and the hydrochloric acid concentration) of the noble metal solution), and is used to add the diluent to the noble metal solution to adjust the nitric acid concentration in the noble metal solution to the noble metal ion (M) in the noble metal solution. n+ ) concentration and less than 1.5 mol / L.

[0049] As the diluent, for example, a solution containing at least one selected from water, hydrochloric acid and nitric acid can be cited. The solution obtained by adding the diluent to the noble metal solution [a solution in which the nitric acid concentration (preferably the nitric acid concentration and the hydrochloric acid concentration) are adjusted] is a solution containing a noble metal solution, noble metal ions (M n+ ) and a diluent are referred to as "acidic metal solutions" in this specification.

[0050] When the diluent includes two or more solutions, the two or more solutions may be mixed, or may be stored without mixing before use and mixed when used.

[0051] When the diluent comprises two or more solutions, the mixing ratio of the two or more solutions can be determined according to the noble metal ions (M n+ ) concentration, etc. to set an appropriate mixing ratio.

[0052] The composition and amount of the diluent added are such that the nitric acid concentration and the hydrochloric acid concentration in the system after the diluent is added to the noble metal solution, that is, the nitric acid concentration and the hydrochloric acid concentration in the acidic metal solution, fall within the following ranges.

[0053] The concentration of nitric acid in the acidic metal solution is the precious metal ion (M n+ ) concentration, from the viewpoint of improving the purity of the recovered precious metal (M), preferably 50 mole times or more, more preferably 60 mole times or more, more preferably 100 mole times or more, more preferably 200 mole times or more, more preferably 300 mole times or more, more preferably 400 mole times or more, more preferably 450 mole times or more, more preferably 600 mole times or more, particularly preferably 1000 mole times or more, most preferably 2000 mole times or more, and particularly preferably 3000 mole times or more.

[0054] The nitric acid concentration in the acidic metal solution is preferably the noble metal ion (M n+ ) concentration is less than 20,000 mole times, and in view of the durability of the adsorbent material, it is more preferably less than 12,000 mole times, more preferably less than 10,000 mole times, further preferably less than 8,000 mole times, particularly preferably less than 6,000 mole times, and most preferably less than 5,000 mole times.

[0055] The nitric acid concentration in the acidic metal solution is less than 1.5 mol / L. In terms of durability of the adsorbent material, it is preferably 1.4 mol / L or less, more preferably 1.2 mol / L or less, further preferably 1 mol / L or less, further preferably 0.8 mol / L or less, particularly preferably 0.6 mol / L or less, most preferably 0.5 mol / L or less, and particularly preferably 0.4 mol / L or less. From the viewpoint of improving the purity of the recovered precious metal (M), the nitric acid concentration is preferably 0.001 mol / L or more, more preferably 0.01 mol / L or more, particularly preferably 0.05 mol / L or more, most preferably 0.1 mol / L or more, and particularly preferably 0.2 mol / L or more.

[0056] In addition, the nitric acid concentration in the acidic metal solution is, for example, 0.001 to 8% by weight. From the viewpoint of improving the recovery efficiency of the precious metal, the lower limit of the nitric acid concentration is preferably 0.03% by weight, more preferably 0.05% by weight, more preferably 0.1% by weight, more preferably 0.2% by weight, more preferably 0.3% by weight, more preferably 0.5% by weight, particularly preferably 0.7% by weight, most preferably 1% by weight, and particularly preferably 1.5% by weight. From the viewpoint of improving the recovery efficiency of the precious metal, the upper limit of the nitric acid concentration is preferably 5% by weight, particularly preferably 3% by weight, and most preferably 2.5% by weight.

[0057] The concentration of hydrochloric acid in the acidic metal solution is preferably 1:100 μg / cm2 from the viewpoint of enhancing adsorption interaction and increasing adsorption amount. n+ ) concentration, more preferably 30 mole times or more, more preferably 100 mole times or more, more preferably 150 mole times or more, more preferably 180 mole times or more, more preferably 200 mole times or more, more preferably 300 mole times or more, more preferably 500 mole times or more, more preferably 800 mole times or more, more preferably 1000 mole times or more, more preferably 1200 mole times or more, more preferably 1800 mole times or more, more preferably 2000 mole times or more, more preferably 3000 mole times or more, more preferably 4000 mole times or more, more preferably 5000 mole times or more, more preferably 8000 mole times or more, more preferably 10000 mole times or more.

[0058] The concentration of hydrochloric acid in the acidic metal solution is preferably 1:100% of the noble metal ions (M) to be recovered from the adsorbent in view of the durability of the adsorbent. n+) concentration is 60,000 mole times or less, more preferably 50,000 mole times or less, further preferably 40,000 mole times or less, particularly preferably 30,000 mole times or less, most preferably 20,000 mole times or less, and particularly preferably 15,000 mole times or less.

[0059] From the viewpoint of enhancing adsorption interaction and increasing adsorption amount, the hydrochloric acid concentration in the acidic metal solution is preferably 0.001 mol / L or more, more preferably 0.01 mol / L or more, further preferably 0.1 mol / L or more, particularly preferably 0.3 mol / L or more, most preferably 0.5 mol / L or more, and particularly preferably 0.8 mol / L or more.

[0060] Considering the durability of the adsorbent material, the hydrochloric acid concentration in the acidic metal solution is preferably 6 mol / L or less, more preferably 5 mol / L or less, further preferably 4 mol / L or less, further preferably 3 mol / L or less, particularly preferably 2.5 mol / L or less, most preferably 2.0 mol / L or less, and particularly preferably 1.5 mol / L or less.

[0061] In addition, the concentration of hydrochloric acid in the acidic metal solution is, for example, 0.001 to 13% by weight. From the viewpoint of improving the recovery efficiency of the precious metal, the lower limit of the hydrochloric acid concentration is preferably 0.05% by weight, more preferably 0.1% by weight, more preferably 0.5% by weight, more preferably 1% by weight, particularly preferably 2% by weight, most preferably 2.5% by weight, and particularly preferably 3.0% by weight. From the viewpoint of improving the durability of the adsorbent material, the upper limit of the hydrochloric acid concentration is preferably 9% by weight, more preferably 7% by weight, more preferably 5% by weight, particularly preferably 4% by weight, and most preferably 3.5% by weight.

[0062] (Adsorbent material (3))

[0063] The adsorbent material has the ability to adsorb noble metal ions (M n+ Then, when the adsorbent is brought into contact with an acidic metal solution, the noble metal ions (M n+ ) is adsorbed on the adsorbent material.

[0064] As the adsorbent, it is preferred that the noble metal ions (M) that selectively adsorb the recovery target are n+ ), when the acidic metal solution contains metal ions other than the metal ions to be recovered, it is preferred to use the noble metal ions (M n+) has an adsorption force that is 10 times or more (more preferably 30 times or more, particularly preferably 50 times or more, and most preferably 100 times or more) as great as the adsorption force of metal ions other than the recovery object, and it is particularly preferred to use a component that has the property of not adsorbing metal ions other than the recovery object.

[0065] When the object of recovery is gold ions (Au + and / or Au 3+ ), it is preferred to use an ester having a sugar skeleton (a compound having a sugar skeleton and in which at least one of the hydroxyl groups of the compound is esterified. Hereinafter, it may be referred to as a "sugar ester").

[0066] The sugar ester is preferably a polysaccharide ester.

[0067] The polysaccharide is a compound formed by polymerization of one or more monosaccharides through glycosidic bonds, and the monosaccharides include, for example, glucose, mannose, xylose, galactose, N-acetylglucosamine, N-acetylgalactosamine, fucose, and the like.

[0068] Examples of the polysaccharide include cellulose, amylose, amylopectin, dextran, hemicellulose, chitin, glycogen, agarose, and pectin.

[0069] Among the polysaccharides, those having low solubility in an acidic metal solution are preferred because they can be easily separated by filtration or the like after adsorbing the noble metal ions.

[0070] As the polysaccharide, preferably, among them, a (homo)polymer of glucose such as cellulose, amylose, dextran, etc., more specifically, a compound which is polymerized only by glucose (especially α-glucose or β-glucose) through glycosidic bonds and has a molecular formula [(C6H 10 O5) n ] (wherein n represents the number of repetitions of the glucose unit and is an integer greater than 2).

[0071] The polysaccharide ester includes a compound formed by a condensation reaction between one or more hydroxyl groups of the polysaccharide and at least one oxygen-containing acid selected from carboxylic acid, sulfuric acid, hydroxy acid, phosphoric acid, and the like.

[0072] As the polysaccharide ester, polysaccharide acylate, which is a condensation reaction product of a polysaccharide and a carboxylic acid, is preferred, in view of its particularly excellent adsorption capacity for precious metal ions (especially gold ions) and its low solubility in an acidic metal solution and suppressed swelling in the acidic metal solution, thereby having excellent handleability.

[0073] The polysaccharide acylate is a molecular formula [(C6H10 O5) n ] is a compound in which at least a portion of the hydroxyl groups of the compound represented by is esterified with an acyl group (RC(=O) group). That is, the polysaccharide acylate is a compound of the molecular formula [(C6H 10 O5) n A compound in which at least a part of the hydroxyl groups (-OH groups) of the compound represented by ] is substituted with -OC(=O)R groups.

[0074] R in the RC(=O) group is a hydrocarbon group, which includes an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by bonding these groups.

[0075] The aliphatic hydrocarbon group includes a saturated aliphatic hydrocarbon group and an unsaturated aliphatic hydrocarbon group.

[0076] The saturated aliphatic hydrocarbon group is preferably a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, and particularly preferably a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms. Examples of the saturated aliphatic hydrocarbon group include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, and decyl.

[0077] The unsaturated aliphatic hydrocarbon group is preferably an unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, and particularly preferably an unsaturated aliphatic hydrocarbon group having 2 to 6 carbon atoms. Examples of the unsaturated aliphatic hydrocarbon group include linear or branched alkenyl groups such as vinyl and allyl groups, and alkynyl groups such as ethynyl and propynyl groups.

[0078] The alicyclic hydrocarbon group is preferably an alicyclic hydrocarbon group having 3 to 10 carbon atoms, and examples thereof include cycloalkyl groups such as a cyclopropyl group and a cyclohexyl group.

[0079] The aromatic hydrocarbon group is preferably an aromatic hydrocarbon group having 6 to 14 carbon atoms, and examples thereof include a phenyl group and a naphthyl group.

[0080] In addition, with respect to the polysaccharide acylate, the molecular formula [(C6H 10 O5) n A part of the hydroxyl group (-OH group) of the compound represented by ] may be substituted with -OR group. It should be noted that the R is a hydrocarbon group, and the same examples as those of R in the acyl group (RC(=O) group) can be cited.

[0081] As the polysaccharide acylate, cellulose acylate having a repeating unit represented by the following formula (1) and amylose acylate having a repeating unit represented by the following formula (2) are particularly preferred. In the following formulas (1) and (2), X is the same or different and represents an acyl group (RC (=O) group: R is the same as described above), a hydrocarbon group (R group: R is the same as described above) or a hydrogen atom. Among them, at least one of X is an acyl group.

[0082] [Chemical formula 1]

[0083]

[0084] Examples of the cellulose acylate include cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate.

[0085] Examples of the amylose acylate include amylose acetate, amylose propionate, and amylose butyrate.

[0086] As the sugar ester, at least one selected from the group consisting of cellulose acylate and amylose acylate is preferred, and cellulose acylate is more preferred. Furthermore, as the cellulose acylate, at least one selected from the group consisting of cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate is preferred, and compounds having a repeating unit represented by the above formula (1) in which at least one of the three Xs is an acetyl group, such as cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate, are particularly preferred, and cellulose acetate is particularly preferred.

[0087] The sugar ester components may be used alone or in combination of two or more.

[0088] The total degree of substitution of the ester groups of the sugar ester (or the total degree of substitution of the acyl groups of the polysaccharide acylate) is, for example, 1.0 to 3.0, preferably 1.5 to 3.0, more preferably 2.0 to 3.0, and particularly preferably 2.2 to 2.7. Since the sugar ester (or polysaccharide acylate) having the above degree of substitution adsorbs gold ions with excellent adsorption force, when it contacts with an acidic metal solution containing gold ions, it can efficiently adsorb and recover the gold ions.

[0089] The total degree of acetyl substitution of cellulose acetate in the sugar ester can be determined by the method of Tezuka (Carbonydr. Res. 273, 83 (1995)) described below.

[0090] 1. The unsubstituted hydroxyl groups of a cellulose acetate sample were propionylated using propionic anhydride in pyridine.

[0091] 2. Dissolve the obtained sample in deuterated chloroform and measure 13C-NMR spectrum.

[0092] 3. The carbon signals of the acetyl group appear in the order of the 2nd, 3rd, and 6th positions from the high magnetic field in the region of 169 ppm to 171 ppm, and the carbonyl carbon signal of the propionyl group appears in the same order in the region of 172 ppm to 174 ppm. The degree of substitution of each acetyl group at the 2nd, 3rd, and 6th positions of the glucose ring in the original cellulose acetate can be determined from the abundance ratio of the acetyl group to the propionyl group at the respective corresponding positions.

[0093] The weight average molecular weight (Mw) of the sugar ester (or polysaccharide acylate) is, for example, 50,000 to 1,000,000, preferably 70,000 to 1,000,000, more preferably 100,000 to 1,000,000, further preferably 100,000 to 500,000, and particularly preferably 100,000 to 300,000.

[0094] The dispersity (molecular weight distribution obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn): Mw / Mn) of the sugar ester (or polysaccharide acylate) is, for example, 2-10, preferably 2-8, and particularly preferably 2-5.

[0095] The number average molecular weight (Mn), weight average molecular weight (Mw) and dispersion degree (Mw / Mn) of the sugar ester (or polysaccharide acylate) can be determined by a known method using gel permeation chromatography.

[0096] The shape of the sugar ester (or polysaccharide acylate) is not particularly limited, but in view of excellent adsorption of gold ions, preferably a powdery or spherical shape (for example, an average particle size of about 0.5 to 1 μm), or a fibrous shape [especially a fibrous shape having a single fineness of, for example, 0.05 to 10 deniers (preferably 0.5 to 5.0 deniers, particularly preferably 0.5 to 1.0 deniers) and a total fineness of, for example, 600 to 60,000 deniers (particularly preferably 3,000 to 30,000 deniers) obtained by a dry spinning method such as an electrospinning method] is preferred.

[0097] Regarding the shape of the sugar ester, one type may be used alone, or two or more types may be used in combination.

[0098] The use of the adsorbent is not particularly limited, and examples thereof include separation membranes (or filtration membranes), column fillers, and box fillers. That is, the adsorbent may include a material having a property of adsorbing noble metal ions (M n+ )'s properties, such as separation membranes (or filtration membranes), column fillers, box fillers, etc.

[0099] Examples of methods for using the adsorbent material as a separation membrane include: a method of using the fibrous adsorbent material to form a woven or nonwoven fabric and using it as a separation membrane; a method of attaching the adsorbent material to the surface of a separation membrane formed of components other than the adsorbent material; and the like.

[0100] As a method of using the adsorbent as a column filler or a box filler, there can be cited a method of using a powdered or spherical adsorbent, a granular adsorbent obtained by chopping the fibrous adsorbent, or a material obtained by attaching the adsorbent to the surface of particles, powders, or fibers formed of components other than the adsorbent as a column filler or a box filler. It should be noted that the column filler is filled in a column container for use. In addition, the box filler is filled in a box for use.

[0101] Therefore, the precious metal recovery kit may also include a precious metal dissolving solution, a diluent, and at least one selected from the following components: a component having a property of adsorbing precious metal ions (M n+ ) properties, a separation membrane formed by an adsorbent material having a property of the adsorbent material, a separation membrane containing the adsorbent material, a column filler or a box filler formed by the adsorbent material, a column filler or a box filler containing the adsorbent material, and a column or a box filled with the filler.

[0102] When using the precious metal recovery kit, the precious metal ions (M n+ ) is adsorbed on the adsorbent material. If the adsorbed noble metal ions (M n+ )'s adsorption material is subjected to reduction treatment, calcination treatment, etc., so that high-purity precious metal (M) can be easily recovered.

[0103] Examples of the reduction treatment include contacting with the following reducing agent to reduce the noble metal ions (M n+ ) is reduced and released to precipitate the precious metal (M). In the above treatment method, the precious metal (M) can be released and recovered at low cost and low energy.

[0104] (reducing agent)

[0105] Examples of the reducing agent include compounds having at least one group selected from a hydroxyl group, a thiol group, a carboxyl group, and a group containing a nitrogen atom. The reducing agent may be used alone or in combination of two or more.

[0106] Examples of the compound having a hydroxyl group include alcohols such as 1,4-butanediol, glycerol, and polyethylene glycol; phenols such as hydroquinone; monosaccharides such as glucose; and polysaccharides such as cellulose, carboxymethylcellulose, cyclodextrin, chitin, and chitosan.

[0107] Examples of the compound having a thiol group include thiophenol, methyl mercaptan, ethyl mercaptan, propyl mercaptan, cysteine, 2-mercaptoethanol, and thioglycerol.

[0108] Examples of the compound having a carboxyl group include monocarboxylic acids such as formic acid, acetic acid, propionic acid, and butyric acid; polycarboxylic acids such as oxalic acid, malonic acid, and succinic acid; hydroxymonocarboxylic acids such as lactic acid and glycolic acid; hydroxypolycarboxylic acids such as citric acid and tartaric acid; aminocarboxylic acids such as N,N-dimethylaminoacetic acid and N,N-dimethylaminopropionic acid; and lactones such as ascorbic acid.

[0109] Examples of the compound having a group containing a nitrogen atom include amines such as methylamine, ethylamine, propylamine, monoethanolamine, dimethylamine, diethylamine, N-methylethanolamine, diethanolamine, dimethylethylamine, N-methyldiethanolamine, and N,N-dimethylethanolamine; and amides such as acetamide, propionamide, N-methylformamide, N-methylacetamide, N-methylpropionamide, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0110] Examples of the reducing agent include aldehydes such as formaldehyde and acetaldehyde.

[0111] As the reducing agent, wherein, in the case of having a noble metal ion (M n+ ) coordination, and the noble metal ions (M n+ ) to form a complex, which can convert precious metal ions (M n+ ) is reduced to form a precious metal (M) with excellent stability, preferably a compound having two or more groups selected from hydroxyl, thiol, carboxyl and groups containing nitrogen atoms in one molecule, and particularly preferably a compound having three or more groups selected from hydroxyl, thiol, carboxyl and groups containing nitrogen atoms in one molecule.

[0112] As the reducing agent, the noble metal ions (M n+ ) From the perspective of particle formation, compounds having a pH of 10 or less (preferably pH 10 to 2, more preferably pH 9 to 3) in the reaction system in contact with the adsorbent are preferred, and compounds having hydroxyl and / or carboxyl groups are preferred.

[0113] As the reducing agent, hydroxycarboxylic acid is particularly preferred, and hydroxypolycarboxylic acid is particularly preferred.

[0114] [Precious metal recovery method]

[0115] The precious metal recovery method comprises the following steps: n+ ) is in contact with the solution to make the noble metal ions (Mn+ ) is adsorbed on the component, and the solution contains noble metal ions (M n+ ) and nitric acid, and the concentration of nitric acid is the noble metal ion (M n+ ) concentration and less than 1.5 mol / L.

[0116] The process preferably comprises: a dissolution process, dissolving the precious metal using a precious metal dissolving solution (1); a nitric acid concentration adjustment process, adding a diluent (2) to a solution (= precious metal solution) obtained by dissolving the precious metal using the precious metal dissolving solution (1), adjusting the nitric acid concentration in the precious metal solution to obtain an acidic metal solution; and an adsorption process, bringing an adsorbent (3) into contact with the acidic metal solution so that the precious metal ions in the acidic metal solution are adsorbed onto the adsorbent (3).

[0117] The above-mentioned process may be carried out by any method such as a batch method, a semi-batch method, or a continuous method.

[0118] (Dissolution process)

[0119] The dissolution step is a step of dissolving the precious metal (M) with a precious metal solution (1), for example, by immersing the precious metal (M) in the precious metal solution (1) and stirring at a temperature of 25 to 100° C. for about 1 to 100 hours. The amount of the precious metal solution (1) used is, for example, 1,000 to 100,000 parts by weight, preferably 1,000 to 10,000 parts by weight, relative to 1 part by weight of the precious metal (M). By using the precious metal solution (1) within the above range, the precious metal (M) or a secondary metal resource containing the precious metal (M) is dissolved, thereby obtaining a precious metal ion (M) containing the precious metal ion (M). n+ ) of a precious metal solution.

[0120] (Nitric Acid Concentration Adjustment Step)

[0121] The nitric acid concentration adjustment step is a step of adding a diluent (2) to the precious metal solution obtained through the above step to adjust the nitric acid concentration in the solution. Through this step, an acidic metal solution with adjusted nitric acid concentration is obtained.

[0122] The amount of the diluent added is such that the nitric acid concentration and the hydrochloric acid concentration in the system after the diluent is added to the noble metal solution, that is, the nitric acid concentration and the hydrochloric acid concentration in the acidic metal solution, fall within the following ranges.

[0123] The concentration of nitric acid in the acidic metal solution is the precious metal ion (M n+) concentration, from the viewpoint of improving the purity of the recovered precious metal (M), preferably 50 mole times or more, more preferably 60 mole times or more, more preferably 100 mole times or more, more preferably 200 mole times or more, more preferably 300 mole times or more, more preferably 400 mole times or more, more preferably 450 mole times or more, more preferably 600 mole times or more, particularly preferably 1000 mole times or more, most preferably 2000 mole times or more, and particularly preferably 3000 mole times or more.

[0124] The nitric acid concentration in the acidic metal solution is preferably the noble metal ion (M n+ ) concentration is less than 20,000 mole times, and in view of the durability of the adsorbent material, it is more preferably less than 12,000 mole times, more preferably less than 10,000 mole times, further preferably less than 8,000 mole times, particularly preferably less than 6,000 mole times, and most preferably less than 5,000 mole times.

[0125] The nitric acid concentration in the acidic metal solution is less than 1.5 mol / L. In terms of durability of the adsorbent material, it is preferably 1.4 mol / L or less, more preferably 1.2 mol / L or less, further preferably 1 mol / L or less, further preferably 0.8 mol / L or less, particularly preferably 0.6 mol / L or less, most preferably 0.5 mol / L or less, and particularly preferably 0.4 mol / L or less. From the viewpoint of improving the purity of the recovered precious metal (M), the nitric acid concentration is preferably 0.001 mol / L or more, more preferably 0.01 mol / L or more, particularly preferably 0.05 mol / L or more, most preferably 0.1 mol / L or more, and particularly preferably 0.2 mol / L or more.

[0126] In addition, the nitric acid concentration in the acidic metal solution is, for example, 0.001 to 8% by weight. From the viewpoint of improving the recovery efficiency of the precious metal, the lower limit of the nitric acid concentration is preferably 0.03% by weight, more preferably 0.05% by weight, more preferably 0.1% by weight, more preferably 0.2% by weight, more preferably 0.3% by weight, more preferably 0.5% by weight, particularly preferably 0.7% by weight, most preferably 1% by weight, and particularly preferably 1.5% by weight. From the viewpoint of improving the recovery efficiency of the precious metal, the upper limit of the nitric acid concentration is preferably 5% by weight, particularly preferably 3% by weight, and most preferably 2.5% by weight.

[0127] The concentration of hydrochloric acid in the acidic metal solution is preferably 1:100 μg / cm2 from the viewpoint of enhancing adsorption interaction and increasing adsorption amount. n+) concentration, more preferably 30 mole times or more, more preferably 100 mole times or more, more preferably 150 mole times or more, more preferably 180 mole times or more, more preferably 200 mole times or more, more preferably 300 mole times or more, more preferably 500 mole times or more, more preferably 800 mole times or more, more preferably 1000 mole times or more, more preferably 1200 mole times or more, more preferably 1800 mole times or more, more preferably 2000 mole times or more, more preferably 3000 mole times or more, more preferably 4000 mole times or more, more preferably 5000 mole times or more, more preferably 8000 mole times or more, more preferably 10000 mole times or more.

[0128] The concentration of hydrochloric acid in the acidic metal solution is preferably 1:100% of the noble metal ions (M) to be recovered from the adsorbent in view of the durability of the adsorbent. n+ ) concentration is 60,000 mole times or less, more preferably 50,000 mole times or less, further preferably 40,000 mole times or less, particularly preferably 30,000 mole times or less, most preferably 20,000 mole times or less, and particularly preferably 15,000 mole times or less.

[0129] From the viewpoint of enhancing adsorption interaction and increasing adsorption amount, the hydrochloric acid concentration in the acidic metal solution is preferably 0.001 mol / L or more, more preferably 0.01 mol / L or more, further preferably 0.1 mol / L or more, particularly preferably 0.3 mol / L or more, most preferably 0.5 mol / L or more, and particularly preferably 0.8 mol / L or more.

[0130] Considering the durability of the adsorbent material, the hydrochloric acid concentration in the acidic metal solution is preferably 6 mol / L or less, more preferably 5 mol / L or less, further preferably 4 mol / L or less, further preferably 3 mol / L or less, particularly preferably 2.5 mol / L or less, most preferably 2.0 mol / L or less, and particularly preferably 1.5 mol / L or less.

[0131] In addition, the concentration of hydrochloric acid in the acidic metal solution is, for example, 0.001 to 13% by weight. From the viewpoint of improving the recovery efficiency of the precious metal, the lower limit of the hydrochloric acid concentration is preferably 0.05% by weight, more preferably 0.1% by weight, more preferably 0.5% by weight, more preferably 1% by weight, particularly preferably 2% by weight, most preferably 2.5% by weight, and particularly preferably 3.0% by weight. From the viewpoint of improving the durability of the adsorbent material, the upper limit of the hydrochloric acid concentration is preferably 9% by weight, more preferably 7% by weight, more preferably 5% by weight, particularly preferably 4% by weight, and most preferably 3.5% by weight.

[0132] (Adsorption process)

[0133] The adsorption step is a step of bringing the acidic metal solution obtained through the above step into contact with the adsorbent (3) to adsorb the noble metal ions in the acidic metal solution onto the adsorbent (3).

[0134] As the adsorbent (3), it is preferred to use a material having a property of selectively adsorbing the noble metal ions to be recovered (M n+ ) in a material having properties such as gold ions, it is preferred to use the above-mentioned sugar esters.

[0135] The amount of the adsorbent (3) used is relative to the amount of the noble metal ions (M n+ ) The amount of 1L of an acidic metal solution having a concentration of 100 ppm by weight is, for example, 0.1 to 20 g, preferably 2 to 10 g.

[0136] The pH of the acidic metal solution when in contact with the adsorbent (3) is, for example, 0 to 2.5. n + ), the upper limit of pH is preferably 2.0, particularly preferably 1.5, and most preferably 1.

[0137] The time for which the adsorbent (3) is in contact with the acidic metal solution is, for example, 10 minutes or more, preferably 30 minutes to 300 minutes. The solution temperature when the adsorbent is in contact with the acidic metal solution is, for example, 5 to 60°C, preferably 5 to 30°C.

[0138] There is no particular limitation on the method of bringing the adsorbent (3) into contact with the acidic metal solution. The adsorbent (3) may be immersed in the acidic metal solution, or the acidic metal solution may be circulated in a component having the adsorbent. For example, when the adsorbent (3) is a separation membrane, a method of circulating the acidic metal solution in a component having the separation membrane may be adopted. In addition, when the adsorbent (3) is a column filler or a box filler, a method of filling the adsorbent (3) into a container to form a column or a box and circulating the acidic metal solution in the component having the column or the box may be adopted.

[0139] A schematic flow chart of one embodiment of the precious metal recovery method is shown in Figure 1 , Figure 2 .

[0140] The precious metal recovery method may also have other steps in addition to the above steps, for example, a separation step may be provided to separate the precious metal ions (M n+ ) from adsorbent materials to separate precious metal ions (M n+ ).

[0141] As adsorbed noble metal ions (M n+ ) from adsorbent materials to separate precious metal ions (M n+ ) method, for example, a reduction treatment method, a calcination treatment method, etc. can be cited. Among them, considering that the metal can be separated with low energy, it is preferred to use a reducing agent and a noble metal ion (M) adsorbed thereon. n+ ) of the adsorbent material, and the noble metal ions (M n+ ) is reduced to separate it from the adsorbent material.

[0142] As the reducing agent, the reducing agents exemplified above can be preferably used.

[0143] The amount of the reducing agent used is, for example, 0.1 to 0.5 parts by weight, preferably 0.1 to 0.3 parts by weight, relative to 1 part by weight of the adsorbent (3).

[0144] As a reducing agent, the noble metal ion (M) adsorbed on the adsorbent (3) n+ ) contact method, for example: immersing the adsorbed noble metal ion (M) in a solution in which a reducing agent is dissolved; n+ ) of the adsorbent material (3); in the use of a cleaning solution without a reducing agent to clean the adsorbed precious metal ions (M n+ ) of the adsorbent material (3) thereby allowing the noble metal ions (M n+ ) is separated, a reducing agent is added to make the noble metal ions (M n+ ) colloid and recover the colloid. In addition, when the adsorbent (3) is a separation membrane, the following method can be adopted: immersing the adsorbent having adsorbed noble metal ions (M) in a solution having a reducing agent dissolved therein; n+ ) separation membrane method; adsorbing noble metal ions (M n+ ) is set in a module, and a solution containing a reducing agent is circulated therein. Furthermore, when the adsorbent (3) is a column filler or a cartridge filler, a method can be adopted in which: a solution containing a reducing agent is circulated in a module having a column or a cartridge filled with a filler that adsorbs precious metal ions; a cleaning solution is circulated in the module to allow the precious metal ions (M n+ ) is separated, so that the reducing agent and the separated precious metal ions (M n+ ) reaction method.

[0145] The reducing agent reacts with the noble metal ions (M) adsorbed on the adsorbent (3). n+ ) The temperature during the contact is, for example, 80 to 120° C. The contact time is, for example, about 10 to 30 minutes.

[0146] The reaction in the separation step may be carried out by any method such as batchwise, semi-batchwise, or continuous. The reaction in the separation step may be carried out in a system different from that of the reaction in the previous step, or may be carried out in the same system.

[0147] After the separation step, a solution containing the noble metal (M) is obtained (preferably a colloid in which the noble metal (M) is dispersed in the solution). Furthermore, if the solution containing the noble metal (M) is subjected to a method such as centrifugal separation, ultrafiltration, evaporation, concentration, etc., the noble metal (M) can be recovered.

[0148] According to the precious metal recovery method, in order to n+ ) and in an acidic metal solution having a specific nitric acid concentration, the noble metal ions (M n+ ) is adsorbed on the adsorbent material and the precious metal ions (M n+ ), for example, when the object of recovery is gold, if an adsorbent material having the property of selectively adsorbing gold is used, then in the acidic metal solution, gold and other metals (such as tin, platinum, palladium, etc.) exist in the form of nitrates that are easily soluble in solvents. Therefore, after gold is adsorbed on the adsorbent material, the adsorbent material can be recovered from the acidic metal solution, thereby easily separating other metals, suppressing the mixing of other metals, and recovering high-purity gold.

[0149] According to the method for recovering precious metals, precious metals (M) (particularly gold) dissolved in a solution can be recovered simply and efficiently. Therefore, the method for recovering precious metals is particularly preferably a method for recovering gold.

[0150] [Precious metal recovery device]

[0151] The precious metal recovery device is a device for recovering precious metals (M) by the precious metal recovery method, and comprises the following units: n+ ) is in contact with the solution to make the noble metal ions (M n+ ) is adsorbed on the member, and the solution contains the noble metal ions (M n+ ) and nitric acid, and the concentration of nitric acid is the noble metal ion (M n+ ) concentration and less than 1.5 mol / L.

[0152] The unit preferably comprises: a dissolving unit for dissolving the noble metal (M) with a noble metal dissolving solution (1); a nitric acid concentration adjusting unit for adding a diluent (2) to a solution (=noble metal solution) in which the noble metal (M) is dissolved to adjust the nitric acid concentration in the solution to obtain an acidic metal solution; and an adsorption unit for bringing the acidic metal solution into contact with an adsorbent (3) to adsorb the noble metal ions (M) in the acidic metal solution. n+) is adsorbed on the adsorbent material (3).

[0153] The adsorption unit includes, for example, a device having the ability to selectively adsorb noble metal ions (M n+ ) or a separation membrane formed of an adsorbent having a property of the adsorbent material or a separation membrane containing the adsorbent material, a column filler or a cartridge filler formed of the adsorbent material or a column filler or a cartridge filler containing the adsorbent material, or a column or a cartridge filled with the filler. The adsorption unit may also include a stirring device.

[0154] The precious metal recovery device may also have other units in addition to the above, for example, it may have: a separation unit for separating the adsorbent material (3) adsorbed with precious metal ions from the acidic metal solution; and a recovery unit for recovering the adsorbent material (M n+ ) is subjected to reduction treatment on the adsorbent material (3) to recover the precious metal (M).

[0155] The recovery unit may include, for example, a reducing agent dropping device, a stirring device, a reflux device, and the like.

[0156] If the precious metal recovery device is used, the precious metal (especially gold) contained in the secondary metal resources can be recovered simply and efficiently. Therefore, the precious metal recovery device is particularly preferably a gold recovery device.

[0157] The above-mentioned configurations and combinations of configurations of the present disclosure are merely examples, and additions, omissions, substitutions, and changes to the configurations may be appropriately made without departing from the gist of the present disclosure.

[0158] Example

[0159] Hereinafter, the present disclosure will be described in more detail by way of examples, but the present disclosure is not limited by these examples but only by the description of the claims.

[0160] Example 1

[0161] (Acidic Metal Solution Preparation)

[0162] Water was added as a diluent to the aqua regia to dilute the aqua regia 3 times. Gold (III) chloride (manufactured by Sigma-Aldrich), hexachloroplatinum (IV) hexahydrate (Tokyo Chemical Industry Co., Ltd.), iron (III) chloride hexahydrate (manufactured by FUJIFILM Wako Chemicals Co., Ltd.), and zinc chloride (manufactured by FUJIFILM Wako Chemicals Co., Ltd.) were added to the aqua regia diluted 3 times to prepare an acidic metal solution 1.

[0163] The concentration of each metal ion in the acidic metal solution 1 (sometimes referred to as "initial metal ion concentration") is as follows.

[0164] Au ion concentration: 14ppm.

[0165] Pt ion concentration: 62ppm.

[0166] Fe ion concentration: 18ppm.

[0167] Zn ion concentration: 28ppm.

[0168] (Adsorption test)

[0169] To the obtained acidic metal solution 1 (20 mL), 40 mg of powdered cellulose acetate (total degree of acetyl substitution: 2.4, Mw: 190,000, Mw / Mn: 2.2) was added as an adsorbent, and the mixture was stirred at room temperature for 3 hours.

[0170] Then, the powdered cellulose acetate was removed by filtration from the acidic metal solution and analyzed using an ICP emission spectrometer (trade name "Agilent 5110", manufactured by Agilent Technologies Co., Ltd.)

[0171] The amount of each metal ion in the filtrate (sometimes referred to as "metal ion concentration after adsorption test") was measured, and the adsorption rate of each metal ion by powdered cellulose acetate was calculated according to the following formula. The results are shown in Table 1 below.

[0172] Adsorption rate (%) = [(initial metal ion concentration - metal ion concentration after adsorption test) / initial metal ion concentration] × 100

[0173] Embodiments 2 to 4

[0174] The same procedure as in Example 1 was carried out except that the amount of the diluent used was changed in the acidic metal solution preparation step.

[0175] Example 5

[0176] In the adsorption test step, powdered cellulose acetate propionate (total substitution degree: 1.98, acyl substitution degree = 0.07, Mw: 75000) was used as the adsorbent instead of powdered cellulose acetate.

[0177] The same procedure as in Example 2 was carried out except for this point.

[0178] Comparative Examples 1 and 2

[0179] The same procedure as in Example 1 was carried out except that the amount of the diluent used was changed in the acidic metal solution preparation step.

[0180] As a result, in the adsorption test, the adsorbent was dissolved in the acidic metal solution, and the adsorbent after the adsorption test could not be removed by filtration.

[0181] Comparative Example 3

[0182] Instead of using aqua regia, gold (III) chloride (manufactured by Sigma-Aldrich) was added to water.

[0183] Hexachloroplatinum (IV) hexahydrate (manufactured by Tokyo Chemical Industry Co., Ltd.), iron (III) chloride hexahydrate (manufactured by FUJIFILM Wako Chemicals Co., Ltd.), and zinc chloride (manufactured by FUJIFILM Wako Chemicals Co., Ltd.)

[0184] Chemicals Co., Ltd.), and a metal aqueous solution (the concentration of each metal ion is the same as above) was prepared.

[0185] The adsorption test was carried out in the same manner as in Example 1 except that the above-mentioned metal aqueous solution was used instead of the acidic metal solution 1.

[0186] [Table 1]

[0187] Table 1

[0188]

[0189] Example 6

[0190] (Acidic Metal Solution Preparation)

[0191] 4.2 mg of gold wire (diameter 0.20 mm, purity 99.95%, manufactured by Nilaco Corporation) was added to 100 mL of aqua regia, and the mixture was stirred at room temperature for 16 hours to dissolve the gold wire, thereby obtaining a gold solution.

[0192] 200 mL of water was added as a diluent to the obtained gold solution. Thus, an acidic metal solution 6 was obtained. The gold ion concentration in the obtained acidic metal solution 6 was 14 ppm. The concentration of other metal ions was 0 ppm.

[0193] The adsorption test was carried out in the same manner as in Example 1, except that the acidic metal solution 6 was used instead of the acidic metal solution 1. The results are shown in Table 2 below.

[0194] Comparative Example 4

[0195] The same procedure as in Example 6 was performed except that 100 mL of concentrated hydrochloric acid (manufactured by FUJIFILM Wako Chemicals Co., Ltd.) was used instead of 100 mL of aqua regia in the acidic metal solution preparation step. However, the gold wire could not be dissolved even after stirring at room temperature for 16 hours. Therefore, the adsorption test could not be performed.

[0196] [Table 2]

[0197] Table 2

[0198]

[0199] As can be seen from Tables 1 and 2 above, when the nitric acid concentration in the acidic metal solution is within a specific range, gold ions can be selectively and efficiently adsorbed to the sugar ester as an adsorbent and recovered.

[0200] On the other hand, if the nitric acid concentration is excessive, the sugar ester will dissolve, making it difficult to adsorb and recover the gold ions.

[0201] Furthermore, in an aqueous solution not containing nitric acid, metal ions other than gold ions are crystallized and filtered out together with the sugar ester adsorbing the gold ions, making it difficult to recover high-purity gold.

[0202] Therefore, by using the precious metal recovery kit of the present disclosure, precious metals contained in the secondary metal resources can be dissolved into a solution and selectively recovered.

[0203] As a summary of the above, the configuration of the present disclosure and its modifications are described below.

[0204] [1] A precious metal recovery kit, which is a kit for recovering precious metals (M), comprising the following precious metal dissolving solution, the following diluent and the following adsorbent.

[0205] Precious metal dissolving solution: contains hydrochloric acid and nitric acid, and the hydrochloric acid / nitric acid (molar ratio) is 2-6.

[0206] Dilution: The concentration of nitric acid in the precious metal solution obtained by dissolving the precious metal (M) in the precious metal solution is adjusted to the concentration of the precious metal ions (M) in the precious metal solution. n+ ) concentration and less than 1.5 mol / L.

[0207] Adsorption material: has the ability to adsorb precious metal ions (M n+ )'s properties.

[0208] [2] The precious metal recovery kit according to [1], wherein the precious metal dissolving solution is aqua regia.

[0209] [3] The precious metal recovery kit according to [1] or [2], wherein the adsorbent is an ester having a sugar skeleton.

[0210] [4] The precious metal recovery kit according to [1] or [2], wherein the adsorbent is a polysaccharide acylate.

[0211] [5] The precious metal recovery kit according to any one of [1] to [4], wherein the adsorbent material comprises a material having a property of adsorbing precious metal ions (M n+) of a separation membrane, a column filler or a box filler.

[0212] [6] The precious metal recovery kit according to any one of [1] to [5], which is a kit for recovering precious metal (M) from secondary metal resources containing precious metal (M).

[0213] [7] A method for recovering precious metals, comprising the following steps: n+ ) is in contact with the solution to make the noble metal ions (M n+ ) is adsorbed on the component, and the solution contains noble metal ions (M n+ ) and nitric acid, and the concentration of nitric acid is the noble metal ion (M n+ ) concentration and less than 1.5 mol / L.

[0214] [8] A method for recovering precious metals, comprising the following steps.

[0215] Step 1: Dissolve the noble metal in the following noble metal dissolving solution to obtain a noble metal ion (M n+ ) of the solution.

[0216] Step 2: Containing precious metal ions (M n+ ) solution has a nitric acid concentration of noble metal ions (M n+ ) concentration to 10 times or more and less than 1.5 mol / L to obtain an acidic metal solution.

[0217] Step 3: A step of bringing the following adsorbent into contact with the obtained acidic metal solution to adsorb the noble metal ions in the acidic metal solution onto the adsorbent.

[0218] Precious metal dissolving solution: contains hydrochloric acid and nitric acid, and the hydrochloric acid / nitric acid (molar ratio) is 2-6.

[0219] Adsorption material: has the ability to adsorb precious metal ions (M n+ )'s properties.

[0220] [9] A method for recovering precious metals, comprising the following steps.

[0221] Step 1: Dissolve the noble metal (M) in the following noble metal dissolving solution to obtain a noble metal ion (M n+ ) of the solution.

[0222] Step 2: In the presence of noble metal ions (M n+ ) to obtain an acidic metal solution.

[0223] Step 3: A step of bringing the following adsorbent into contact with the obtained acidic metal solution to adsorb the noble metal ions in the acidic metal solution onto the adsorbent.

[0224] Precious metal dissolving solution: contains hydrochloric acid and nitric acid, and the hydrochloric acid / nitric acid (molar ratio) is 2-6.

[0225] Dilution: The concentration of nitric acid in the precious metal solution obtained by dissolving the precious metal (M) in the precious metal solution is adjusted to the concentration of the precious metal ions (M) in the precious metal solution. n+ ) concentration and less than 1.5 mol / L.

[0226] Adsorption material: has the ability to adsorb precious metal ions (M n+ )'s properties.

[0227]

[10] A method for recovering precious metals from secondary metal resources containing precious metals, comprising the following steps.

[0228] Step 1: Dissolve the secondary metal resource containing the precious metal with the following precious metal dissolving solution to obtain a precious metal ion (M n+ ) of the solution.

[0229] Step 2: Containing precious metal ions (M n+ ) solution has a nitric acid concentration of noble metal ions (M n+ ) concentration to 10 times or more and less than 1.5 mol / L to obtain an acidic metal solution.

[0230] Step 3: A step of bringing the following adsorbent into contact with the obtained acidic metal solution to adsorb the noble metal ions in the acidic metal solution onto the adsorbent.

[0231] Precious metal dissolving solution: contains hydrochloric acid and nitric acid, and the hydrochloric acid / nitric acid (molar ratio) is 2-6.

[0232] Adsorption material: has the ability to adsorb precious metal ions (M n+ )'s properties.

[0233]

[11] A precious metal recovery device comprising the following units: n+ ) is in contact with the solution to make the noble metal ions (M n+ ) is adsorbed on the component, and the solution contains noble metal ions (M n+ ) and nitric acid, and the concentration of nitric acid is the noble metal ion (M n+ ) concentration and less than 1.5 mol / L.

[0234]

[12] A precious metal recovery device comprising the following units: a unit for dissolving a precious metal (M) with the following precious metal dissolving solution; a unit for adding the following diluent to the solution containing the precious metal (M) to obtain an acidic metal solution; and a unit for bringing the acidic metal solution into contact with the following adsorbent to remove the precious metal ions (M) in the acidic metal solution. n+ ) is adsorbed to an adsorbent material.

[0235] Precious metal dissolving solution: contains hydrochloric acid and nitric acid, and the hydrochloric acid / nitric acid (molar ratio) is 2-6.

[0236] Dilution: The concentration of nitric acid in the precious metal solution obtained by dissolving the precious metal (M) in the precious metal solution is adjusted to the concentration of the precious metal ions (M) in the precious metal solution. n+ ) concentration and less than 1.5 mol / L.

[0237] Adsorption material: has the ability to adsorb precious metal ions (M n+ )'s properties.

[0238] Industrial Applicability

[0239] By using the precious metal recovery kit of the present disclosure, it is possible to recover high-purity precious metals (M) from secondary metal resources in an energy-saving manner by a simple method without using a unit that requires a large amount of thermal energy.

Claims

1. A precious metal recovery kit, which is a kit for recovering precious metals (M), comprising the following precious metal dissolving solution, the following diluent and the following adsorption material, Precious metal solution: contains hydrochloric acid and nitric acid, the molar ratio of hydrochloric acid to nitric acid is 2 to 6, Dilution liquid: a liquid used to dilute a precious metal solution obtained by dissolving a precious metal (M) in the precious metal solution, and to adjust the nitric acid concentration in the precious metal solution to the precious metal ion (M) in the precious metal solution. n+ ) concentration is 10 times or more and less than 1.5 mol / L, Adsorption material: has the ability to adsorb precious metal ions (M n+ )'s properties.

2. The precious metal recovery kit according to claim 1, wherein: The noble metal dissolving liquid is aqua regia.

3. The precious metal recovery kit according to claim 1, wherein: The adsorbent material is an ester having a sugar backbone.

4. The precious metal recovery kit according to claim 1, wherein: The adsorption material is polysaccharide acylate.

5. The precious metal recovery kit according to claim 1, wherein: The adsorbent material comprises a material having a function of adsorbing noble metal ions (M n+ ) of a separation membrane, a column filler or a box filler. 6 . The precious metal recovery kit according to claim 1 , which is a kit for recovering precious metals (M) from secondary metal resources containing precious metals (M).

7. A method for recovering precious metals, comprising the following steps: n+ ) is in contact with the solution to make the noble metal ions (M n+ ) is adsorbed on the component, and the solution contains noble metal ions (M n+ ) and nitric acid, and the concentration of nitric acid is the noble metal ion (M n+ ) concentration and less than 1.5 mol / L.

8. A precious metal recovery device, comprising the following units: n+ ) is in contact with the solution to make the noble metal ions (M n+ ) is adsorbed on the component, and the solution contains noble metal ions (M n+ ) and nitric acid, and the concentration of nitric acid is the noble metal ion (M n+ ) concentration and less than 1.5 mol / L.

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