METHOD FOR RECOVERING METALS, METHOD FOR DETERMINING METALS, AND METHOD FOR PRODUCING POTASSIUM HYDROXIDE

Abstract

To provide a method for recovering a metal efficiently from a mixture containing multiple kinds of metals.SOLUTION: There is provided a method for recovering a metal from a mixture containing multiple kinds of metals. The method includes a step for recovering the metal from the mixture by using a chelate resin solid phase A having a carboxymethylated polyethyleneimine group, and a chelate resin solid phase B having an iminodiacetic acid group.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for recovering metals, a method for quantifying metals, and a method for producing potassium hydroxide. [Background technology]

[0002] Recovery of metals from mixtures containing multiple substances is a technique required for various purposes, such as high purification of products manufactured in precision engineering, the medical and pharmaceutical fields, the food industry, etc., purification of wastewater from various industries, desalinization of seawater, analysis, etc. One known method for recovering metals involves contacting a chelating resin with the mixture and using the chelating resin to capture the metal.

[0003] For example, Patent Document 1 discloses a chelating resin adsorbent having an iminodiacetic acid group. It is said that this chelating resin can selectively adsorb and desorb heavy metal ions such as cobalt, nickel, and copper dissolved in small amounts in water. In addition, Patent Document 2 proposes a method of using a chelating fiber into which a functional group having a chelating ability has been introduced as a treatment method capable of capturing heavy metals such as copper, zinc, nickel, cobalt, chromium, molybdenum, and tungsten, or metalloids such as boron, germanium, arsenic, antimony, selenium, and tellurium contained in an aqueous or oily liquid.

[0004] Furthermore, as a method for increasing the efficiency of adsorption and removal of metals, Patent Document 3 proposes a filter cartridge in which two types of filtration base fabrics are laminated or wound around a hollow inner cylinder. The filtration base fabric in the filter cartridge of Patent Document 3 includes a nonwoven fabric layer A located on the downstream side and a nonwoven fabric layer B located on the upstream side, the nonwoven fabric layer A being composed of polyolefin fibers to which a sulfonic acid group is chemically bonded as a metal adsorption group, and the nonwoven fabric layer B being composed of polyolefin fibers to which at least one selected from an amino group, an N-methyl-D-glucamine group, an iminodiacetic acid group, an iminodiethanol group, an amidoxime group, a phosphoric acid group, a carboxylic acid group, and an ethylenediaminetriacetic acid group is chemically bonded as a metal adsorption group. Patent Document 3 also discloses that sodium and copper can be removed from a metal solution containing sodium and copper by using the above filter cartridge. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 2772010 [Patent Document 2] International Publication No. 2002 / 060824 Brochure [Patent Document 3] JP 2018-167223 A Summary of the Invention [Problem to be solved by the invention]

[0006] For example, in the production of potassium hydroxide, the amount of metals in the potassium hydroxide is quantified to measure the purity of the potassium hydroxide obtained. At this time, the potassium hydroxide contains many kinds of metals. According to the methods of Patent Documents 1 to 3, it is possible to recover a plurality of kinds of metals, but there are some metals that cannot be recovered, and the efficiency of metal recovery is not satisfactory. Therefore, there is a demand for a method for more efficiently recovering metals from a mixture containing a plurality of kinds of metals.

[0007] An object of the present invention is to provide a method for efficiently recovering metals from a mixture containing a plurality of metals. Another object of the present invention is to provide a method for efficiently quantifying metals contained in potassium hydroxide. [Means for solving the problem]

[0008] As a result of extensive research, the inventors discovered that by using two types of chelating resin solid phases having specific structures, it is possible to recover metals all at once from a mixture containing multiple metals, and thus completed the present invention.

[0009] That is, the present invention is as follows. [1] 1. A method for recovering metals from a mixture containing multiple metals, comprising the steps of: The method comprises the step of recovering metals from the mixture using a solid phase A of a chelating resin having a carboxymethylated polyethyleneimine group and a solid phase B of a chelating resin having an iminodiacetic acid group. [2] The chelating resin solid phase A has a structure represented by formula (I), The chelating resin solid phase B has a structure represented by formula (II): The method described in [1].

[0010] [ka]

[0011] [3] The method includes a liquid passing step of passing the mixture through a chelating resin solid phase A and a chelating resin solid phase B in this order. The method according to [1] or [2]. [4] After the liquid passing step, an elution step is included in which the metal adsorbed by the chelating resin is eluted from the chelating resin solid phase B and then the chelating resin solid phase A in that order. The method according to any one of [1] to [3]. [5] The pH of the mixture is in the range of 3.0 to 7.0. The method according to any one of [1] to [4]. [6] The mixture contains at least one metal selected from Cr, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Mo, Ag, Cd, Sn, and Pd; The method according to any one of [1] to [5]. [7] The metals contained in the mixture and the metals recovered from the mixture include at least Cr. The method according to any one of [1] to [6]. [8] The metals contained in the mixture and the metals recovered from the mixture include at least Ag. The method according to any one of [1] to [7]. [9] The mixture comprises an alkali metal compound and / or an alkaline earth metal compound. The method according to any one of [1] to [8].

[10] The mixture includes potassium hydroxide. The method according to any one of [1] to [9].

[11] A method for quantifying metals contained in an alkali metal compound and / or an alkaline earth metal compound, comprising the steps of: a step of passing an aqueous solution of an alkali metal compound and / or an alkaline earth metal compound through a chelating resin solid phase A having a carboxymethylated polyethyleneimine group and a chelating resin solid phase B having an iminodiacetic acid group in this order; After the liquid passing step, an elution step of eluting the metal adsorbed by the chelating resin from the chelating resin solid phase B and then the chelating resin solid phase A in that order; and A method for quantifying metals, comprising a step of quantifying the amount of metal contained in the eluate obtained in the elution step.

[12] The pH of the aqueous solution of the alkali metal compound and / or alkaline earth metal compound is in the range of 3.0 to 7.0. A method for quantifying metals according to

[11] .

[13] The metal includes at least one selected from Cr, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Mo, Ag, Cd, Sn, and Pd; A method for quantifying metals according to

[11] or

[12] .

[14] The chelating resin solid phase A has a structure represented by formula (I), The chelating resin solid phase B has a structure represented by formula (II): The method for quantifying a metal according to any one of

[11] to

[13] .

[0012] [ka]

[0013]

[15] A method for quantifying metals contained in potassium hydroxide. The quantitative method according to any one of

[11] to

[14] .

[16] A method for producing an alkali metal compound and / or an alkaline earth metal compound, comprising the steps of:

[11] -

[14] A production method comprising a step of quantifying a metal in an alkali metal compound and / or an alkaline earth metal compound by using the method for quantifying a metal according to any one of the above.

[17] A method for producing potassium hydroxide, The manufacturing method described in

[16] . Effect of the Invention

[0014] According to the present invention, it is possible to efficiently recover metals from a mixture containing a plurality of metals. Also, according to the present invention, it is possible to efficiently quantify the metals contained in potassium hydroxide and produce potassium hydroxide.

[0015] Hereinafter, the embodiments of the present invention will be described in detail. Note that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the present invention.

[0016] <Method of recovering metals> The method of the present invention is a method for recovering metals from a mixture containing multiple metals. The method of the present invention includes a step of recovering metals from the mixture using a solid phase A of a chelating resin having a carboxymethylated polyethyleneimine group and a solid phase B of a chelating resin having an iminodiacetic acid group. In the present invention, recovery refers to collecting metals from a mixture containing multiple metals and other substances by adsorbing them onto a chelating resin. Here, adsorption occurs through interaction between the functional groups contained in the chelating resin and the metal ions to form chelates.

[0017] When using one chelating resin to recover metals from a mixture containing multiple metals, the target metal mixture is brought into contact with the chelating resin, and the metal is retained by the chelating resin. At that time, since the impurity elements contained in the mixture are also retained by the chelating resin, the chelating resin is washed with a solvent such as water, and the target metal is then eluted from the chelating resin, thereby separating the metal from the mixture. Although the metal is recovered by a series of operations using one chelating resin, it is difficult to recover multiple metals at once, since some metal species are not retained by the chelating resin. Therefore, the washing liquid obtained by washing with the above solvent must be used again for the series of operations using the chelating resin. According to the method of the present invention, by using two specific resins, it is possible to efficiently separate and recover a variety of metals in one operation without carrying out a series of operations twice.

[0018] In particular, the method of the present invention is suitable for recovering metals contained in alkali metal compounds or alkaline earth metal compounds. In addition to the alkali metal or alkaline earth metal that is the main component derived from these compounds, the alkali metal or alkaline earth metal compound may also contain other metals. According to the method of the present invention, the other metals can be separated / recovered from a mixture derived from an alkali metal or alkaline earth metal and containing a plurality of metals. The mixture in the method of the present invention is, for example, a mixture derived from potassium hydroxide. The mixture in the present invention is preferably an aqueous solution.

[0019] In the present invention, "multiple kinds" refers to two or more kinds. The metals recovered from the mixture may be all or some of the metal types contained in the mixture. From the viewpoint of efficient recovery of metals, the ratio of the types of metals recovered to the types of metals contained in the mixture (number of metal types recovered / number of metal types contained in the mixture) is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, even more preferably 90% or more, even more preferably 95% or more, and particularly preferably all types.

[0020] The chelating resin solid phase in the present invention is a solid phase containing a resin having a functional group that forms a chelate with a metal ion introduced therein. The functional group that forms a chelate with a metal ion in the chelating resin solid phase A is a carboxymethylated polyethyleneimine group. The functional group that forms a chelate with a metal ion in the chelating resin solid phase B is an iminodiacetic acid group. The functional group that forms a chelate with a metal ion is bound to the resin of the carrier.

[0021] The carboxymethylated polyethyleneimine group is a group having a carboxylmethyl group on at least some of the nitrogen atoms of the ethyleneimine units constituting the polyethyleneimine group. The carboxymethylated polyethyleneimine group is, for example, a group containing the following formula (1).

[0022] [ka]

[0023] In formula (1), x and y are any integers, and the ethyleneimine units having a carboxymethyl group may be present randomly or as a block polymer. Each of x and y may be in the range of 0 to 1000, and may be in the range of 0 to 500, 0 to 200, or 0 to 100. However, it is preferable that both x and y are not 0, but are both 1 or more. It is also preferable that x>y is satisfied. The black dots in formula (1) represent bonds to adjacent atoms.

[0024] The iminodiacetic acid group is a group derived from iminoacetic acid. The iminodiacetic acid group is, for example, a group containing the following formula (2). It is preferable that the chelating resin solid phase B contains the iminodiacetic acid group alone as a functional group that forms a chelate with a metal ion.

[0025] [ka]

[0026] The black dots in formula (2) represent bonds to adjacent atoms.

[0027] The chelating resin solid phase A preferably has a structure represented by formula (I).

[0028] [ka]

[0029] In formula (I), x and y are any integers, and the ethyleneimine unit having a carboxymethyl group may be present randomly or as a block polymer. x and y are the same as x and y in formula (1), and are the same preferred embodiments. In formula (I), the black dots represent bonds to adjacent atoms, and preferably represent bonds to a resin carrier.

[0030] The chelating resin solid phase B preferably has a structure represented by formula (II).

[0031] [ka]

[0032] The black dots in formula (II) represent bonds to adjacent atoms, and preferably represent bonds to a resin carrier.

[0033] The resin in the present invention is not particularly limited, and may be, for example, a polymer or copolymer of an olefin compound or a halogenated olefin compound. Here, the olefin compound and the halogenated olefin compound may contain at least one unsaturated double bond, and may also include an acrylate compound and a methacrylate compound. Specifically, the resin may preferably include a polymer such as polyethylene, polypropylene, polysulfone, polytetrafluoroethylene, polystyrene, divinylbenzene polymer, glycidyl methacrylate polymer, or ethylene dimethacrylate polymer; a copolymer derived from any one selected from ethylene, propylene, butene, hexene, styrene, divinylbenzene, glycidyl methacrylate, ethylene dimethacrylate, tetrafluoroethylene, or chlorotrifluoroethylene; or the like. The chelate resin solid phase in the present invention can be obtained, for example, by exposing a polymer molded article made of a polymer or copolymer of the above-mentioned olefin compound or halogenated olefin compound to ionizing radiation, graft-polymerizing a polymerizable monomer containing an epoxy group, and then introducing a carboxymethylated polyethyleneimine group or an iminodiacetic acid group into the side chain of the graft polymer. The chelate resin in the present invention can also be obtained by obtaining a polymer using a monomer having an epoxy group, for example, glycidyl methacrylate, and introducing a carboxymethylated polyethyleneimine group or an iminodiacetic acid group into the polymer. The method for obtaining the chelate resin solid phase is not limited to this. The resin of the chelating resin solid phase A preferably comprises a glycidyl methacrylate / ethylene dimethacrylate copolymer.The resin of the chelating resin solid phase B preferably comprises a styrene / divinylbenzene copolymer.

[0034] The chelating resin solid phase in the present invention can be selected from a variety of shapes, including fibers and non-woven fibers, particles, powders, as well as woven fabrics, sheets, and the like.

[0035] The chelating resin solid phase A and the chelating resin solid phase B are commercially available.

[0036] The order in which the mixture in the present invention is passed through the chelating resin solid phase A and the chelating resin solid phase B is not particularly limited, but it is preferable to pass the mixture through the chelating resin solid phase A and the chelating resin solid phase B successively in this order.

[0037] The method of the present invention may include a step of eluting the metal from the chelating resin solid phases A and B after passing the mixture. In the method of the present invention, it is preferable to include an elution step of eluting the metal adsorbed by the chelating resin in the order of the chelating resin solid phase B and the chelating resin solid phase A after the liquid passing step. It is preferable to use an acid aqueous solution for elution. The acid is not particularly limited, and examples thereof include hydrochloric acid, sulfuric acid, and nitric acid. These may be used alone or in combination of two or more.

[0038] The size and shape of the chelating resin solid phase A and the chelating resin solid phase B are not particularly limited and may be appropriately adjusted depending on the amount of the target material to be subjected to the recovery process. Each of the chelating resin solid phase A and the chelating resin solid phase B may be configured so that a plurality of chelating resin solid phases A and chelating resin solid phases B are stacked. Furthermore, the chelating resin solid phase A and the chelating resin solid phase B may be arranged so that the object to be subjected to the recovery process passes continuously through these resins, and the chelating resin solid phase A and the chelating resin solid phase B may be arranged so that they are in contact with each other, or a flow path may be provided between the chelating resin solid phase A and the chelating resin solid phase B.

[0039] The pH of the mixture in the present invention is not particularly limited, but is preferably in the range of 3.0 to 7.0. By setting the pH range to 3.0 to 7.0, multiple metals tend to be separated / recovered more efficiently in a single operation. The lower limit of the pH may be 3.5 or more, 4.0 or more, 4.5 or more, or 5.0 or more. The upper limit of the pH may be 6.5 or less, or 6.0 or less. These upper and lower limits can be appropriately combined. The pH in the present invention is more preferably 3.5 or more and 6.5 or less, and further preferably 4.0 or more and 6.0 or less. The pH in the present invention can be appropriately adjusted by adding a pH adjuster such as aqueous ammonia or nitric acid. The pH in the present invention can be measured, for example, by a pH measuring device, specifically, by the method described in the Examples.

[0040] The metals contained in the mixture of the present invention and the metals recovered from the mixture preferably contain at least Cr. The metals contained in the mixture of the present invention and the metals recovered from the mixture preferably contain at least Ag. It is more preferable that the metals contained in the mixture of the present invention and the metals recovered from the mixture preferably contain at least Cr and Ag.

[0041] The mixture in the present invention preferably contains at least one metal selected from, for example, chromium (Cr), aluminum (Al), titanium (Ti), vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), gallium (Ga), molybdenum (Mo), silver (Ag), cadmium (Cd), tin (Sn), and palladium (Pd). The metal recovered from such a mixture preferably contains at least one metal selected from Cr, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Mo, Ag, Cd, Sn, and Pd. Furthermore, the mixture in the present invention preferably contains at least Cr and Ag among Cr, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Mo, Ag, Cd, Sn, and Pd, and more preferably contains all of these metals. The metals recovered from such a mixture preferably contain at least Cr and Ag among Cr, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Mo, Ag, Cd, Sn, and Pd, and more preferably contains all of these metals.

[0042] In the present invention, the metal in the mixture or the recovered metal may be in the form of any one of a metal element, a metal ion, and a metal salt. In addition, the valence of the metal is not particularly limited.

[0043] As an embodiment of the mixture of the present invention, it is preferably derived from an alkali metal compound and / or an alkaline earth metal compound, more preferably from potassium hydroxide. That is, the mixture of the present invention preferably contains an alkali metal compound and / or an alkaline earth metal compound, more preferably from potassium hydroxide. This mixture preferably contains at least one metal selected from, for example, Cr, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Mo, Ag, Cd, Sn, and Pd, more preferably contains at least Cr and Ag among these, and further preferably contains all of these metals.

[0044] The concentration of the metal to be recovered in the mixture in the present invention is not particularly limited, but is preferably a trace amount. The concentration of the metal to be recovered is usually in the range of 0.1 ppb to 1000 ppb, preferably 0.1 ppb to 800 ppb, more preferably 0.3 ppb to 500 ppb, as the metal element. Metals can be characterized and quantified by subjecting samples of interest to Inductively Coupled Plasma-Mass Spectrometry.

[0045] The mixture in the present invention is preferably prepared from an appropriate alkali metal compound and / or an alkaline earth metal compound, and can be prepared by dissolving an alkali metal compound and / or an alkaline earth metal compound in an aqueous solution. Depending on the type of metal in the mixture, a reducing agent may be added appropriately to adjust the valence of the metal and increase the recovery efficiency. For example, when the mixture contains chromium, the chromium may be hexavalent chromium, but it is preferable to add a reducing agent to make it trivalent chromium. The reducing agent is not particularly limited, but for example, hydroxylamine can be used, and specifically, reduction can be performed by blending nitric acid and hydroxylamine hydrochloride in the mixture.

[0046] The method of the present invention is capable of recovering metals from a mixture containing a plurality of metals, thereby enabling purification or separation of the object to be subjected to the method of the present invention.

[0047] <Method for determining metals contained in alkali metal compounds and / or alkaline earth metal compounds> As described above, in one embodiment of the method of the present invention, metals can be recovered from a mixture containing an alkali metal compound and / or an alkaline earth metal compound, preferably potassium hydroxide. According to this method, alkali metals such as potassium and / or alkaline earth metals are not adsorbed to the chelating resin solid phase A and the chelating resin solid phase B, while metals other than alkali metals and alkaline earth metals in the mixture are adsorbed to these resin solid phases and recovered. The metals thus recovered can be qualitatively and quantitatively analyzed. Therefore, one aspect of the present invention is a method for quantifying metals contained in alkali metal compounds and / or alkaline earth metal compounds, preferably a method for quantifying metals contained in potassium hydroxide. The quantitative determination method of the present invention includes a liquid passing step of passing an aqueous solution of an alkali metal compound and / or alkaline earth metal compound through a chelating resin solid phase A having a carboxymethylated polyethyleneimine group and a chelating resin solid phase B having an iminodiacetic acid group in this order, an elution step of eluting the metals adsorbed by the chelating resin from the chelating resin solid phase B and then the chelating resin solid phase A in that order after the liquid passing step, and a step of quantifying the metals contained in the eluate obtained in the elution step.

[0048] The aqueous solution of an alkali metal compound and / or an alkaline earth metal compound can be prepared from an alkali metal compound and / or an alkaline earth metal compound, and can be prepared by obtaining an already prepared aqueous solution, or can be prepared by preparing the aqueous solution by oneself. Here, depending on the type of metal in the aqueous solution, a reducing agent may be added appropriately to adjust the valence of the metal and improve the recovery efficiency. For example, when the aqueous solution contains chromium, the chromium may be hexavalent chromium, but it is preferable to add a reducing agent to make it trivalent chromium. The reducing agent is not particularly limited, but for example, hydroxylamine can be used, and specifically, reduction can be performed by mixing nitric acid and hydroxylamine hydrochloride in the aqueous solution.

[0049] The pH of the aqueous solution of the alkali metal compound and / or alkaline earth metal compound in the quantitative determination method of the present invention is not particularly limited, but is preferably in the range of 3.0 to 7.0. By setting the pH range to 3.0 to 7.0, the metals in the alkali metal compound and / or alkaline earth metal compound tend to be separated / recovered more efficiently. The lower limit of the pH may be 3.5 or more, 4.0 or more, 4.5 or more, or 5.0 or more. The upper limit of the pH may be 6.5 or less, or 6.0 or less. These upper and lower limits can be appropriately combined. The pH is more preferably from 3.5 to 6.5, and further preferably from 4.0 to 6.0. The methods for adjusting and measuring the pH are the same as those for adjusting and measuring the pH in the above <Method for recovering metals>.

[0050] The metals that may be contained in the alkali metal compound and / or alkaline earth metal compound in the quantitative determination method of the present invention are as described above in <Method for recovering metals>. That is, the alkali metal compound and / or alkaline earth metal compound preferably contains at least one metal selected from, for example, Cr, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Mo, Ag, Cd, Sn, and Pd, more preferably contains at least Cr and Ag among these, and further preferably contains all of these metals.

[0051] The details of the chelating resin solid phase A and the chelating resin solid phase B in the quantitative determination method of the present invention are as described above in the section <Method of recovering metals>. In addition, the chelating resin solid phase A and the chelating resin solid phase B in the quantitative determination method of the present invention may be commercially available products, and for example, Presep (registered trademark) polychelate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) may be suitably used as the chelating resin solid phase A, and Empore (registered trademark) (manufactured by 3M Japan Ltd.) may be suitably used as the chelating resin solid phase B. The chelating resin solid phase A and the chelating resin solid phase B in the quantitative determination method of the present invention may be either a disk type or a cartridge type.

[0052] In the elution step, it is preferable to use an aqueous acid solution for elution. The acid is not particularly limited, and examples thereof include hydrochloric acid, sulfuric acid, and nitric acid. These may be used alone or in combination of two or more. Among these acids, nitric acid is preferable. By using nitric acid, polyatomic ions that are an obstacle to analysis when performing qualitative and quantitative analysis of metals using inductively coupled plasma-mass spectrometry tend to be suppressed.

[0053] The method for quantifying a metal of the present invention allows the amount of metal in potassium hydroxide to be quantified, and is therefore useful, for example, for measuring the purity of potassium hydroxide obtained in the production of potassium hydroxide. Therefore, one aspect of the present invention is a method for producing potassium hydroxide, which includes a step of quantifying metals in potassium hydroxide using the method for quantifying metals contained in potassium hydroxide according to the present invention. The method for producing potassium hydroxide is not particularly limited and may be any known method. Potassium hydroxide can be produced, for example, by electrolyzing potassium chloride. EXAMPLES

[0054] EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0055] <Metal element analysis method> The sample to be measured was analyzed using Inductively Coupled Plasma-Mass Spectrometry (hereinafter also referred to as ICP-MS), apparatus name: Agilent 7500cs, manufactured by Agilent Technologies, Inc., to qualitatively and quantitatively analyze metal elements.

[0056] <pH measurement method> The pH of the sample was measured using a pH measuring device (apparatus name: pH meter F-52, manufactured by Horiba, Ltd.).

[0057] [Example 1] An aqueous potassium hydroxide solution was used as the sample. Specifically, 2 g of potassium hydroxide was weighed, 1.5 mL of nitric acid and 1.5 mL of a 200 mM hydroxylamine hydrochloride aqueous solution were added in sequence, and ultrapure water was added to make the total volume 100 mL for use. The types and added concentrations of metal elements in this sample were as shown in Table 1. Also, the pH of the sample was 4.5 or more and 5.0 or less. The pH adjustment was performed by adding aqueous ammonia and nitric acid while stirring with a magnetic stirrer using a pH measuring device. Presep Polychelate (manufactured by Fujifilm Wako Pure Chemical Corporation) was used as the chelating resin solid phase A having a carboxymethylated polyethyleneimine group. The chelating resin solid phase A was subjected to a treatment of passing 5 mL of methanol and 10 mL of ultrapure water in sequence. Empore Disk Cartridge Chelate (manufactured by 3M Japan Limited) was used as the chelating resin solid phase B having an iminodiacetic acid group. They were connected so that the sample solution was passed through the chelating resin solid phase A and the chelating resin solid phase B in this order. 10 mL of 4N nitric acid, 20 mL of ultrapure water, and 10 mL of a 100 mM ammonium acetate aqueous solution adjusted to pH 5.5 were passed through this chelating resin solid phase set in sequence. Thereby, the chelating resin solid phase was washed and adjusted. Next, 100 mL of the sample was passed through the chelating resin solid phase set so that the sample solution was passed through the chelating resin solid phase A and the chelating resin solid phase B in this order. Thereby, the metal in the sample was adsorbed onto the chelating resin solid phase set. Subsequently, 10 mL of a 100 mM aqueous ammonium acetate solution adjusted to pH 5.5 and 10 mL of ultrapure water were passed through the chelating resin solid phase A and then the chelating resin solid phase B in this order to wash the chelating resin solid phase set. Furthermore, 3 mL of 4N nitric acid was passed through the chelating resin solid phase B and then the chelating resin solid phase A in that order to elute the metals adsorbed by the chelating resin. Ultrapure water was added to the eluate to make the total amount 10 g, and the metal elements were qualitatively and quantitatively analyzed according to the above-mentioned <Method of Analyzing Metal Elements>.

[0058] [Example 2] The same procedure as in Example 1 was carried out, except that the types and concentrations of metal elements in the samples in Example 1 were as shown in Table 1. The concentrations of the metal elements were adjusted by adding a 10 ppb mixed standard solution.

[0059] [Example 3] The same procedure as in Example 1 was carried out, except that the types and concentrations of metal elements in the samples in Example 1 were as shown in Table 1. The concentrations of the metal elements were adjusted by adding a 10 ppb mixed standard solution.

[0060] [Example 4] The same procedure as in Example 1 was carried out, except that the types and concentrations of metal elements in the samples in Example 1 were as shown in Table 1. The concentrations of the metal elements were adjusted by adding a 10 ppb mixed standard solution.

[0061] [Comparative Example 1] The same procedure as in Example 1 was carried out except that only Empore Disk Cartridge Chelate (manufactured by 3M Japan Ltd.) was used as the solid phase. The metal elements contained in the eluate were quantified, and the Ag concentration was found to be 0 ppb, meaning that Ag could not be recovered.

[0062] [Comparative Example 2] The same procedure as in Example 1 was carried out except that only Presep Polychelate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as the solid phase. As a result of quantifying the metal elements contained in the eluate, the concentration of Cr was 0 ppb, and Cr could not be recovered.

[0063] [Comparative Example 3] The same procedure as in Example 1 was carried out except that only Novias (manufactured by Hitachi High-Tech Fielding Corp.), a chelating resin solid phase having ethylenediaminetriacetic acid groups and iminodiacetic acid groups, was used as the solid phase. The metal elements contained in the eluate were quantified, and the Cr concentration was found to be 0 ppb, meaning that Cr could not be recovered.

[0064] The concentrations of metal elements added to the samples are shown in Table 1. The amounts added (ppb) in Table 1 represent the concentrations per sample.

[0065] [Table 1]

[0066] The quantitative results of the metal elements contained in the eluate of the example are shown in Table 2.

[0067] [Table 2]

[0068] The metal recovery rates in Examples 1 to 4 are shown in Table 3. Here, the metal recovery rate refers to a value calculated from the following formula.

[0069] The recovery rate is a value calculated by the following formula (1).

[0070]

number

[0071] The amount of metal in the aqueous potassium hydroxide solution in formula (1) is the value calculated from the following formula (2).

[0072]

number

[0073] When the amount added was 0 ppb, the recovery rate was assumed to be equal to that at each added concentration, and was calculated using the following formula (3).

[0074]

number

[0075] The recovery rate at each added concentration was calculated using the following formula by substituting formula (3) into formula (1).

[0076]

number

[0077] The recovery rate calculated by the above method may exceed 100%, but the reason for this is that the recovery rate at 0 ppb is lower than the recovery rate at each concentration, or the quantitative result of the metal amount in the eluate is higher. In particular, the latter is caused by a change in the sensitivity of the ICP-MS when the composition of the eluate differs from that of the standard solution of the calibration curve, resulting in a higher quantitative result.

[0078] [Table 3]

[0079] [Reference Example 1] Differences in Cr and Ag recovery rates of chelating resin due to differences in pH The sample preparation method was the same as in Example 1, except that the pH of the preparation solution was adjusted to 3.5, 4.5, 5.5, and 6.5, and the concentration of the metal element was adjusted by adding 2 g of a 10 ppb mixed standard solution. 10mL of 4N nitric acid, 20mL of ultrapure water, and 10mL of 100mM ammonium acetate aqueous solution adjusted to pH 5.5 were passed through Presep Polychelate, Empore Disk Cartridge Chelate, and Novias, in that order. Here, 5mL of methanol was passed through Presep Polychelate, and 5mL of acetone was passed through Novias before passing 4N nitric acid. This allowed the chelating resin solid phase to be washed and adjusted. Samples having different pH values ​​were passed through Presep Polychelate, Empore Disk Cartridge Chelate, and Novias. The passing of the samples, the subsequent washing and elution, and the qualitative and quantitative analysis of metal elements were carried out in the same manner as in Example 1. When the solution was passed through PreSep Polychelate, the Ag recoveries at pH 3.5, 4.5, 5.5, and 6.5 were 27%, 89%, 100%, and 99%, respectively. When the solution was passed through an Empore disk cartridge chelate, the Cr recoveries at pH 3.5, 4.5, 5.5, and 6.5 were 85%, 89%, 68%, and 17%, respectively. When the solution was passed through Novias, the Ag recoveries at pH 3.5, 4.5, 5.5, and 6.5 were <5%, <5%, 20%, and 77%, respectively. [Industrial Applicability]

[0080] INDUSTRIAL APPLICABILITY According to the method of the present invention, metals can be recovered from a mixture containing a plurality of metals, and the method has industrial applicability in the fields of purification and analysis of metal-containing products.

Claims

1. 1. A method for recovering metals from a mixture containing multiple metals, comprising the steps of: The method includes a step of recovering metals from the mixture using a solid phase A of a chelating resin having a carboxymethylated polyethyleneimine group and a solid phase B of a chelating resin having an iminodiacetic acid group, The method includes a step of passing the mixture through a chelating resin solid phase A and a chelating resin solid phase B in this order.

2. The chelating resin solid phase A has a structure represented by formula (I), The chelating resin solid phase B has a structure represented by formula (II): The method of claim 1. 【Chemistry 1】 (In formula (I), x and y are any integers.)

3. After the liquid passing step, an elution step is included in which the metal adsorbed by the chelating resin is eluted from the chelating resin solid phase B and then the chelating resin solid phase A in that order. The method according to claim 1 or 2.

4. The pH of the mixture is in the range of 3.0 to 7.

0. The method according to any one of claims 1 to 3.

5. The mixture contains at least one metal selected from Cr, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Mo, Ag, Cd, Sn, and Pd; The method according to any one of claims 1 to 4.

6. The metals contained in the mixture and the metals recovered from the mixture include at least Cr. The method according to any one of claims 1 to 5.

7. The metals contained in the mixture and the metals recovered from the mixture include at least Ag. The method according to any one of claims 1 to 6.

8. The mixture comprises an alkali metal compound and / or an alkaline earth metal compound. The method according to any one of claims 1 to 7.

9. The mixture includes potassium hydroxide. The method according to any one of claims 1 to 8.

10. A method for quantifying metals contained in an alkali metal compound and / or an alkaline earth metal compound, comprising the steps of: a step of passing an aqueous solution of an alkali metal compound and / or an alkaline earth metal compound through a chelating resin solid phase A having a carboxymethylated polyethyleneimine group and a chelating resin solid phase B having an iminodiacetic acid group in this order; an elution step of eluting the metal adsorbed by the chelating resin from the chelating resin solid phase B and the chelating resin solid phase A in this order after the liquid passing step; and A method for quantifying metals, comprising a step of quantifying the amount of metal contained in the eluate obtained in the elution step.

11. The pH of the aqueous solution of the alkali metal compound and / or alkaline earth metal compound is in the range of 3.0 to 7.

0. The method for quantifying a metal according to claim 10.

12. The metal includes at least one selected from Cr, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Mo, Ag, Cd, Sn, and Pd; The method for quantifying a metal according to claim 10 or 11.

13. The chelating resin solid phase A has a structure represented by formula (I), The chelating resin solid phase B has a structure represented by formula (II): The method for quantifying a metal according to any one of claims 10 to 12. 【Chemistry 2】 (In formula (I), x and y are any integers.)

14. A method for quantifying metals contained in potassium hydroxide. The quantitative method according to any one of claims 10 to 13.

15. A method for producing an alkali metal compound and / or an alkaline earth metal compound, comprising the steps of: A production method comprising a step of quantifying metals in an alkali metal compound and / or an alkaline earth metal compound using the method for quantifying metals according to any one of claims 10 to 13.

16. A method for producing potassium hydroxide, The method of claim 15.

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