JPH0521033B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for eluting metals adsorbed on a chelating agent, and more specifically, in eluting metals from a chelating agent that has adsorbed metals, the present invention relates to a method for eluting metals from a chelating agent that contains one or more reducing agents. This invention relates to a method for eluting metals using a basic aqueous solution. (Prior art) Conventionally, the elution of metals adsorbed onto chelating agents has generally been carried out by contacting the chelating agent that has adsorbed metals with an aqueous solution of mineral acids such as sulfuric acid or hydrochloric acid. However, if this method is used,
When the chelating agent has a functional group that does not have acid resistance, such as an oxime group or a phosphoric acid ester group, this is not preferable because the performance deteriorates due to decomposition of the functional group. For example, strongly acidic ion exchange resin or -
Chelating agents with phosphorus-based functional groups such as PO(OR) ₂ and -PH(OR) ₃ have strong bonds with heavy metals, and it may be difficult to elute metals such as molybdenum, vanadium, and uranium using conventional methods. many. Therefore, mineral acids containing hydrogen peroxide and mineral acid solutions containing metal ions are used to elute these metals with strong binding strength. (Problems to be Solved by the Invention) However, elution using a mineral acid solution has problems such as a low elution rate and the need for large amounts of hydrogen peroxide and metal. In view of these circumstances, the present inventors conducted studies to develop a method for eluating metals adsorbed on chelating agents that overcomes the above-mentioned disadvantages, and found that an aqueous base solution containing a reducing agent was used as an eluent. By using it as a solvent, the elution rate is fast, it is possible to elute with a relatively low concentration eluent, and metals can be recovered in liquid form up to a high concentration range, and it essentially does not cause deterioration of the absorbent. They discovered this and completed the present invention. (Means for Solving the Problems) That is, the present invention is characterized by using an aqueous solution containing a reducing agent and a basic compound as the eluent in eluting the metal adsorbed on the chelating agent with an eluent. The present invention provides a method for eluting metals adsorbed on a chelating agent. The chelating agent targeted by the method of the present invention is not particularly limited and can be applied to any chelating agent, but in particular, =NOH,
−P(OR) ₂ , −PO(OR) ₂ , −PH(OR) ₃ , −SR, =
A functional group selected from NOH, -N(R) ₂ , -N(R) ₃ (wherein R represents the same or different hydrogen, phenyl group, alkyl group or alkenyl group) or a metal salt thereof It is suitable for chelating agents having at least one of the following. The chelating agents preferably used in the above-mentioned method of the present invention are chelating agents that are relatively stable under basic conditions and unstable under acidic conditions, and generally include (1) acrylonitrile, α-chloroacrylonitrile, vinylidene cyanide. , polymers of vinyl cyanide monomers such as methacrylonitrile, or copolymers of vinyl cyanide monomers and other ethylenically unsaturated monomers that can be copolymerized with hydroxylamine or hydroxyl. A chelate resin that has an amidoxime group by reacting an amine derivative, (2) Reacting hydroxylamine or a hydroxylamine derivative with a vinyl cyanide monomer such as acrylonitrile, α-chloroacrylonitrile, vinylidene cyanide, methacrylonitrile, etc. (3) halogenated alkyl groups such as chloromethyl group, bromomethyl group, or bromine, iodine, etc. a styrene-divinylbenzene copolymer containing a halogen atom,
Phosphine obtained by reacting a phosphine compound such as lithium diphenylphosphine, sodium diphenylphosphine, lithium phenylphosphine, tricresylphosphine, or a mixture thereof with a polymer such as phenolic resin, polyethylene, or polypropylene. (4) Styrene-divinylbenzene copolymers containing halogenated alkyl groups such as chloromethyl groups and bromomethyl groups, phenolic resins, aniline resins, m-phenylene polymers (hereinafter referred to as halogenated phosphorous acid derivatives such as triethyl phosphite, triphenyl phosphite, trimethyl phosphite, or mixtures thereof (hereinafter referred to as phosphorous acid derivatives). A chelate resin having a phosphonate group obtained by (5) a resin having a primary or secondary amino group, diethyl chloromethylphosphonate,
Aminoalkylene phosphate groups obtained by reacting halogenated alkyl phosphates such as ethyl chloromethyl phosphonate, diphenyl chloromethyl phosphonate, dicresyl chloromethyl phosphonate, ethyl chloromethyl phosphonate, or mixtures thereof; (6) Hydrolyzing the chelate resin having an aminoalkylene phosphate group or changing the phosphorous acid derivative used in the production of the aminoalkylene phosphate group-containing resin to phosphorous acid. A chelate resin having an aminoalkylene phosphate group obtained by a similar reaction, (7) a styrene-divinylbenzene copolymer containing a halogenated alkyl group such as a chloromethyl group or a bromomethyl group, or a halogen atom such as bromine or iodine. A chelate resin having a tertiary or quaternary amino group obtained by reacting dimethylamine, diethylamine, trimethylamine, triethylamine, dimethylethanolamine, etc. with
(8) Others dibutyl phosphate, 2-ethylhexyl-phenylphosphonic acid ester, dibutyl [(diethyl-carbamoyl)methyl]phosphonic acid ester, di-(2-ethylhexyl)-phosphoric acid ester, 4-nonyl-salicylaldoxime, O
Examples include various poorly water-soluble chelating agents such as -hydroxy-p-nonyl-acetophenone oxime, laurylamide oxime, 4-octylbenzamide oxime, and 2-ethylhexylisobutyldithiophosphoric acid. In the chelating agent of the present invention, a metal salt is a metal salt formed by an ionic bond, a chelate bond, or a complex bond between a functional group in the chelating agent and a metal, and the bonding force of the salt formation is between the functional group and the metal. There are no particular restrictions on the metal as long as it is a metal whose bonding force is weaker than that of the metal to be adsorbed and recovered. Metals for forming such metal salts generally include alkali metals and alkaline earth metals such as sodium, potassium, calcium, and magnesium. The metal-adsorbed chelate resin used in the present invention may be one in which the metal is adsorbed by any method. The type of metal to be adsorbed is also not particularly limited, but metals that easily become oxides or oxygen-containing compounds such as uranium, molybdenum, rhenium, titanium, vanadium, germanium, and tungsten are preferred. In carrying out the method of the present invention, an aqueous solution containing a reducing agent and a basic compound and having a concentration of 0.001 to 3N and 0.05N or higher, respectively, is preferably used as the eluent. When a basic aqueous solution with a reducing agent concentration of less than 0.001 normal is used as an eluent, metal elution does not substantially occur or the metal elution rate is slow;
It takes a long time for elution, and on the other hand, even if it exceeds 3N, it is difficult to obtain a proportional effect. Further, even if the concentration of the reducing agent is 0.001 to 3N, it is not preferable if the concentration of the basic compound is lower than 0.05N because the rate of metal removal is slow and elution takes a long time. Therefore, by combining a reducing agent with a specific concentration and a basic aqueous solution with a specific concentration as described above, it is possible to achieve the desired elution rate and to recover metal components in liquid form, while also reducing the substantial amount of adsorbent. It becomes an eluent that does not cause deterioration. The constituent components of the eluent used in the method of the present invention include, as reducing agents, lower oxides or salts thereof such as sulfurous acid, nitrous acid, sulfur dioxide, and thiosulfate; metal hydrides such as sodium borohydride;
Or hydrazine, hydroxylamine, hydroquinone, oxalic acid, formaldehyde or derivatives thereof. In addition, as other basic compounds,
Examples include inorganic alkali compounds such as sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, and ammonia, and water-soluble organic amines such as ethylenediamine, diethylenetriamine, diethylamine, and triethylamine. Such a reducing agent and a basic compound are mixed and used as an aqueous solution. The eluent is basically used as an aqueous solution as described above, but it may contain an organic solvent as long as it does not interfere with the contact treatment. The amount of eluent to be used is not particularly limited and varies depending on the type and concentration of the eluent, the type of chelating agent, the type and content of the adsorbed metal, but this can be determined by conducting preliminary experiments as appropriate. It can be set accordingly. The contact temperature between the chelating agent that has adsorbed the metal and the eluent is not particularly limited, but is usually between 0 and 0.
Performed at 100℃. The contact time is also not particularly limited. The contact method is not particularly limited, and examples include a method in which the eluent is passed through a column filled with a resinous chelating agent, a method in which the resinous chelating agent is immersed in the eluent, and then overseparation is performed. Add a liquid chelating agent to the eluent, and after contact stirring,
A method such as static separation is adopted. Eluted metal-containing liquid (hereinafter abbreviated as eluent)
Although it varies depending on the type of metal and its purpose, it can be recovered as a metal hydroxide through neutralization, oxidation, etc., or the eluate can be directly treated with a reducing agent, electrolyzed, etc. , metals can be recovered. The chelating agent from which the metal ions have been eluted in this way can be used as is or as needed with water and/or sodium hydroxide, potassium hydroxide,
After treatment with a basic aqueous solution such as calcium hydroxide, magnesium hydroxide, or ammonia, or an acidic aqueous solution such as hydrochloric acid, sulfuric acid, nitric acid, or phosphoric acid, it can be used repeatedly as an adsorption collector for metal ions. (Effects of the Invention) According to the method of the present invention described in detail above, special functional groups having a strong binding force with heavy metals, such as -P
It is now possible to easily elute metals from chelating agents containing (OR) ₂ , -PO(OR) ₂ , =NOH, -N ⁺ (OR) _3, etc., significantly increasing the elution rate and elution rate. It became possible. In addition, the component concentration of the eluent used in the method of the present invention is
Compared to the eluent concentration commonly used in the past,
Since it can be used at a fairly low concentration, it suppresses the deterioration of the resin and essentially does not cause deterioration due to the eluent, so its industrial significance is extremely great. Hereinafter, the present invention will be explained in more detail with reference to examples, but it goes without saying that the present invention is not limited to the following examples unless it exceeds the gist thereof. Examples 1 to 13, Comparative Examples 1 to 6 Sumikylate MC-95 (chelating agent having aminomethylene phosphonic acid group, manufactured by Sumitomo Chemical Co., Ltd.)
Pack 10ml into a column with an inner diameter of 10m/m, and add a sulfuric acid aqueous solution with a uranium concentration of 100mg/m to a column with a downward space velocity.
The liquid was passed for 1 hour at 10 hr ^-1 to adsorb uranium. Next, an eluent having the composition shown in Table 1 was passed through the reactor at room temperature in a downward flow at a space velocity of 10 hr ^-1 for 1 hour to elute the uranium adsorbed on the chelating agent. The uranium concentration in the obtained eluate was as shown in Table 1.

【table】

[Table] Example 14 Resin-like chelating agent having a -CS(SH) group obtained by reacting a copolymer of acrylonitrile and divinylbenzene with ethylenediamine and carbon disulfide
Fill a column with an inner diameter of 10 m/m with 50 ml of a solution containing 120 mg/m of molybdenum and 10 wt% NaCl.
Molybdenum was adsorbed by passing 1500 ml of the solution for 3 hours. Then, after flowing down 200 ml of water, the concentrations of hydroxylamine and caustic soda were each 0.1.
1000 ml of a mixed aqueous solution of normal and 0.5 normal was passed at room temperature for 1 hour to elute molybdenum adsorbed on the chelating agent. Then ion exchange water
After rinsing with 200 ml of water, the above method was used to pass the molybdenum-containing solution and elute and regenerate it 20 times. When the molybdenum adsorption rate for the first time was 100, the adsorption rate for the 20th time was 98%. Ta. Comparative Example 5 A molybdenum-containing solution was passed and elution regeneration was carried out in exactly the same manner as above except that the eluent used in Example 14 was changed to a 2N sulfuric acid aqueous solution.
The adsorption rate at the 20th time was 12% when the molybdenum adsorption rate at the first time was set as 100. Examples 15 to 29 Using 5 ml of each of the following chelating agents A to O, contact treatment was performed for 3 hours with 100 ml of a 0.5 N hydrochloric acid aqueous solution containing 100 mg of rhenium, and each chelate was adsorbed with rhenium. A chelating agent or chelating agent solution was obtained. Table 2 shows the adsorption amount of each rhenium. Each rhenium adsorption chelating agent was treated with sodium sulfite and caustic soda concentrations of 0.01 each.
Mix with 50ml of mixed aqueous solution that is 0.5N,
The amount of rhenium eluted after 3 hours of contact treatment was the second
It was as shown in the table. Comparative Examples 6-20 The same operation as in Examples 15-29 was performed except that 2N sulfuric acid was used, and the amount of rhenium eluted was determined and shown in Table 2. Chelating agent A: =NOH group, =NH group, - obtained by reacting a copolymer of acrylonitrile and divinylbenzene with hydroxylamine sulfate and an aqueous hydrazine solution.
A resinous chelating agent having _NH2 and _-NHNH2 groups. Chelating agent B: A resin having a quaternary phosphonium base obtained by reacting 200 parts by weight of chloromethylated polystyrene and 200 parts by weight of tributylphosphine in a dimethylformamide solvent. Chelating agent C: A resin having a quaternary phosphonium base obtained by reacting 200 parts by weight of chloromethylated polystyrene and 260 parts by weight of triphenylphosphine in a dimethylformamide solvent. Chelating agent D: Lithium polystyrene was obtained by reacting 150 parts by weight of brominated polystyrene with 64 parts by weight of a 1.6 mol% n-butyllithium-hexane solution in tetrahydrofuran solvent. This was added to chlordiphenylphosphin 300 in tetrahydrofuran solvent.
A resin having a phosphine group obtained by reacting with 371 parts by weight of 40% peracetic acid in a methylene chloride solvent. Chelating agent E: A resin containing a sodium salt of phosphonic acid obtained by hydrolyzing chelating agent B in a 20% aqueous solution of caustic soda. Chelating agent F: 100 parts by weight of polystyrene in chloroform solvent,
A resin containing phosphinic acid groups obtained by reacting 150 parts by weight of phosphorus trichloride and then hydrolyzing it. Chelating agent G: A resin having a phosphinate group obtained by reacting 100 parts by weight of aminated polystyrene with 120 parts by weight of cresyl chloromethylphosphinate in a 1,2-dichloroethane solvent. Chelating agent H: Sumikylate MC-95 (manufactured by Sumitomo Chemical Co., Ltd.), a resin having a diethylenetriaminomethylene phosphate group. Chelating agent I: A resin obtained by reacting 1,2-benzisoxazole-3-acetamidoxime, resorcinol, and formalin. Chelating Agent J: Vinyl diamide dioxime-divinylbenzene-acrylic acid copolymer resin obtained by reacting a copolymer of vinylidene cyanide, divinylbenzene, and methyl acrylate with hydroxylamine. Chelating agent K; Sumikylate MC-30 [(Chelating agent having iminodiacetic acid group (manufactured by Sumitomo Chemical)] Chelating agent L; 2-ethylhexyl-phenylphosphonic acid ester chelating agent M; Dibutyl [(diethylcarbamoyl)methyl ]
Phosphonic acid ester chelating agent N; 4-dodecylbenzylaminomethylenephosphonic acid chelating agent O; 2-ethylhexylisobutyldithiophosphoric acid

【table】

【table】

[Table] Examples 30 to 33, Comparative Examples 21 to 24 10 ml of various chelating agents adsorbing various metals shown in Table 3 was packed into a column with an inner diameter of 10 m/m, and
The adsorbed metals were eluted by passing an eluent having the composition shown in the table in a downward flow at room temperature at a space velocity of 5 hr ^-1 for 6 hours, and the results shown in Table 3 were obtained.

【table】

Claims (1)

[Claims] 1. A method for eluting the metal adsorbed on the chelating agent using an aqueous solution containing a reducing agent and a basic compound as the eluent. Elution method. 2 The chelating agent has =NOH, -P in the molecule
(OR) ₂ , −PO(OR) ₂ , −PH(OR) ₃ , −SR, −N(R) ₂
or - A chelating agent having at least one functional group selected from N(R) ₃ (wherein R in the above formula is the same or different and represents hydrogen, a phenyl group, an alkyl group, or an alkenyl group) or a metal salt thereof. A metal elution method according to claim 1. 3. The metal elution method according to claim 1 or 2, wherein the metal is a metal that can become an oxide or an oxygen-containing compound. 4. The metal elution method according to claim 1, 2 or 3, wherein the concentration of the reducing agent in the eluent is 0.001 to 3N and the concentration of the basic compound is 0.05N or more.