JP6320026B2 - Metal recovery method - Google Patents
Metal recovery method Download PDFInfo
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- JP6320026B2 JP6320026B2 JP2013265177A JP2013265177A JP6320026B2 JP 6320026 B2 JP6320026 B2 JP 6320026B2 JP 2013265177 A JP2013265177 A JP 2013265177A JP 2013265177 A JP2013265177 A JP 2013265177A JP 6320026 B2 JP6320026 B2 JP 6320026B2
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- reducing agent
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- 229910052751 metal Inorganic materials 0.000 title claims description 148
- 239000002184 metal Substances 0.000 title claims description 148
- 238000011084 recovery Methods 0.000 title claims description 59
- 238000000034 method Methods 0.000 title claims description 47
- 239000010419 fine particle Substances 0.000 claims description 79
- 239000012528 membrane Substances 0.000 claims description 72
- 239000003638 chemical reducing agent Substances 0.000 claims description 70
- 229910021645 metal ion Inorganic materials 0.000 claims description 69
- 238000001914 filtration Methods 0.000 claims description 33
- 239000012141 concentrate Substances 0.000 claims description 21
- -1 iron ions Chemical class 0.000 claims description 19
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 16
- 229910052742 iron Inorganic materials 0.000 claims description 13
- 150000003839 salts Chemical class 0.000 claims description 12
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 claims description 10
- 229910052763 palladium Inorganic materials 0.000 claims description 9
- 125000004432 carbon atom Chemical group C* 0.000 claims description 8
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 claims description 5
- 235000019253 formic acid Nutrition 0.000 claims description 5
- 150000002500 ions Chemical class 0.000 claims description 5
- 229910052737 gold Inorganic materials 0.000 claims description 4
- 229910052741 iridium Inorganic materials 0.000 claims description 4
- 229910052762 osmium Inorganic materials 0.000 claims description 4
- 229910052697 platinum Inorganic materials 0.000 claims description 4
- 229910052703 rhodium Inorganic materials 0.000 claims description 4
- 229910052707 ruthenium Inorganic materials 0.000 claims description 4
- 229910052709 silver Inorganic materials 0.000 claims description 4
- 239000000243 solution Substances 0.000 description 123
- 238000003860 storage Methods 0.000 description 96
- 238000006243 chemical reaction Methods 0.000 description 57
- 239000012295 chemical reaction liquid Substances 0.000 description 54
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 50
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- 238000006722 reduction reaction Methods 0.000 description 28
- 239000007864 aqueous solution Substances 0.000 description 21
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 18
- 239000007788 liquid Substances 0.000 description 13
- 239000000706 filtrate Substances 0.000 description 10
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 9
- 229910052739 hydrogen Inorganic materials 0.000 description 9
- 239000001257 hydrogen Substances 0.000 description 9
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 description 9
- 229910045601 alloy Inorganic materials 0.000 description 8
- 239000000956 alloy Substances 0.000 description 8
- 239000004280 Sodium formate Substances 0.000 description 7
- 244000005700 microbiome Species 0.000 description 7
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- 235000019254 sodium formate Nutrition 0.000 description 7
- 239000002033 PVDF binder Substances 0.000 description 6
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- 238000000605 extraction Methods 0.000 description 5
- 238000005374 membrane filtration Methods 0.000 description 5
- 239000002923 metal particle Substances 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 150000002429 hydrazines Chemical class 0.000 description 4
- 230000001965 increasing effect Effects 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- 229910001111 Fine metal Inorganic materials 0.000 description 3
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- 239000000463 material Substances 0.000 description 3
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- 238000003756 stirring Methods 0.000 description 3
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 2
- 150000005208 1,4-dihydroxybenzenes Chemical class 0.000 description 2
- YGHRJJRRZDOVPD-UHFFFAOYSA-N 3-methylbutanal Chemical compound CC(C)CC=O YGHRJJRRZDOVPD-UHFFFAOYSA-N 0.000 description 2
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 2
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical compound OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 description 2
- AMIMRNSIRUDHCM-UHFFFAOYSA-N Isopropylaldehyde Chemical compound CC(C)C=O AMIMRNSIRUDHCM-UHFFFAOYSA-N 0.000 description 2
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- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 239000003463 adsorbent Substances 0.000 description 2
- YCIMNLLNPGFGHC-UHFFFAOYSA-N catechol Chemical compound OC1=CC=CC=C1O YCIMNLLNPGFGHC-UHFFFAOYSA-N 0.000 description 2
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- 239000003456 ion exchange resin Substances 0.000 description 2
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- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 2
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical class OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- GHMLBKRAJCXXBS-UHFFFAOYSA-N resorcinol Chemical compound OC1=CC=CC(O)=C1 GHMLBKRAJCXXBS-UHFFFAOYSA-N 0.000 description 2
- 238000001223 reverse osmosis Methods 0.000 description 2
- 150000003852 triazoles Chemical class 0.000 description 2
- HGBOYTHUEUWSSQ-UHFFFAOYSA-N valeric aldehyde Natural products CCCCC=O HGBOYTHUEUWSSQ-UHFFFAOYSA-N 0.000 description 2
- FMCUPJKTGNBGEC-UHFFFAOYSA-N 1,2,4-triazol-4-amine Chemical compound NN1C=NN=C1 FMCUPJKTGNBGEC-UHFFFAOYSA-N 0.000 description 1
- QWENRTYMTSOGBR-UHFFFAOYSA-N 1H-1,2,3-Triazole Chemical compound C=1C=NNN=1 QWENRTYMTSOGBR-UHFFFAOYSA-N 0.000 description 1
- SDXAWLJRERMRKF-UHFFFAOYSA-N 3,5-dimethyl-1h-pyrazole Chemical compound CC=1C=C(C)NN=1 SDXAWLJRERMRKF-UHFFFAOYSA-N 0.000 description 1
- NHLAPJMCARJFOG-UHFFFAOYSA-N 3-methyl-1,4-dihydropyrazol-5-one Chemical compound CC1=NNC(=O)C1 NHLAPJMCARJFOG-UHFFFAOYSA-N 0.000 description 1
- FUSNOPLQVRUIIM-UHFFFAOYSA-N 4-amino-2-(4,4-dimethyl-2-oxoimidazolidin-1-yl)-n-[3-(trifluoromethyl)phenyl]pyrimidine-5-carboxamide Chemical compound O=C1NC(C)(C)CN1C(N=C1N)=NC=C1C(=O)NC1=CC=CC(C(F)(F)F)=C1 FUSNOPLQVRUIIM-UHFFFAOYSA-N 0.000 description 1
- KWSLGOVYXMQPPX-UHFFFAOYSA-N 5-[3-(trifluoromethyl)phenyl]-2h-tetrazole Chemical compound FC(F)(F)C1=CC=CC(C2=NNN=N2)=C1 KWSLGOVYXMQPPX-UHFFFAOYSA-N 0.000 description 1
- PCFMUWBCZZUMRX-UHFFFAOYSA-N 9,10-Dihydroxyanthracene Chemical compound C1=CC=C2C(O)=C(C=CC=C3)C3=C(O)C2=C1 PCFMUWBCZZUMRX-UHFFFAOYSA-N 0.000 description 1
- 229910021577 Iron(II) chloride Inorganic materials 0.000 description 1
- BGRDGMRNKXEXQD-UHFFFAOYSA-N Maleic hydrazide Chemical compound OC1=CC=C(O)N=N1 BGRDGMRNKXEXQD-UHFFFAOYSA-N 0.000 description 1
- 239000005983 Maleic hydrazide Substances 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- WTKZEGDFNFYCGP-UHFFFAOYSA-N Pyrazole Chemical compound C=1C=NNC=1 WTKZEGDFNFYCGP-UHFFFAOYSA-N 0.000 description 1
- 229920000297 Rayon Polymers 0.000 description 1
- IKHGUXGNUITLKF-XPULMUKRSA-N acetaldehyde Chemical compound [14CH]([14CH3])=O IKHGUXGNUITLKF-XPULMUKRSA-N 0.000 description 1
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- IBVAQQYNSHJXBV-UHFFFAOYSA-N adipic acid dihydrazide Chemical compound NNC(=O)CCCCC(=O)NN IBVAQQYNSHJXBV-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- GJYJYFHBOBUTBY-UHFFFAOYSA-N alpha-camphorene Chemical compound CC(C)=CCCC(=C)C1CCC(CCC=C(C)C)=CC1 GJYJYFHBOBUTBY-UHFFFAOYSA-N 0.000 description 1
- BIVUUOPIAYRCAP-UHFFFAOYSA-N aminoazanium;chloride Chemical compound Cl.NN BIVUUOPIAYRCAP-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000012258 culturing Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- YXXXKCDYKKSZHL-UHFFFAOYSA-M dipotassium;dioxido(oxo)phosphanium Chemical compound [K+].[K+].[O-][P+]([O-])=O YXXXKCDYKKSZHL-UHFFFAOYSA-M 0.000 description 1
- ZRRLFMPOAYZELW-UHFFFAOYSA-N disodium;hydrogen phosphite Chemical compound [Na+].[Na+].OP([O-])[O-] ZRRLFMPOAYZELW-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004993 emission spectroscopy Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- IMBKASBLAKCLEM-UHFFFAOYSA-L ferrous ammonium sulfate (anhydrous) Chemical compound [NH4+].[NH4+].[Fe+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O IMBKASBLAKCLEM-UHFFFAOYSA-L 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000012493 hydrazine sulfate Substances 0.000 description 1
- 229910000377 hydrazine sulfate Inorganic materials 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- 229910000358 iron sulfate Inorganic materials 0.000 description 1
- PVFSDGKDKFSOTB-UHFFFAOYSA-K iron(3+);triacetate Chemical compound [Fe+3].CC([O-])=O.CC([O-])=O.CC([O-])=O PVFSDGKDKFSOTB-UHFFFAOYSA-K 0.000 description 1
- DOARWPHSJVUWFT-UHFFFAOYSA-N lanthanum nickel Chemical compound [Ni].[La] DOARWPHSJVUWFT-UHFFFAOYSA-N 0.000 description 1
- 239000012633 leachable Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910000000 metal hydroxide Inorganic materials 0.000 description 1
- 150000004692 metal hydroxides Chemical class 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 150000004682 monohydrates Chemical class 0.000 description 1
- PCILLCXFKWDRMK-UHFFFAOYSA-N naphthalene-1,4-diol Chemical compound C1=CC=C2C(O)=CC=C(O)C2=C1 PCILLCXFKWDRMK-UHFFFAOYSA-N 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- MUJIDPITZJWBSW-UHFFFAOYSA-N palladium(2+) Chemical compound [Pd+2] MUJIDPITZJWBSW-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
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- 239000000126 substance Substances 0.000 description 1
- ISIJQEHRDSCQIU-UHFFFAOYSA-N tert-butyl 2,7-diazaspiro[4.5]decane-7-carboxylate Chemical compound C1N(C(=O)OC(C)(C)C)CCCC11CNCC1 ISIJQEHRDSCQIU-UHFFFAOYSA-N 0.000 description 1
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Manufacture And Refinement Of Metals (AREA)
Description
本発明は、金属回収方法及び金属回収装置に関する。 The present invention relates to a metal recovery method and a metal recovery apparatus.
従来、法規制の水質基準を満たす目的の他、資源の再利用を目的として、産業廃水等や浸出貴液等の金属を含有する溶液から金属を回収することが広く行われている。
特に、低濃度の回収対象金属を含む金属含有溶液からの金属回収は、イオン交換樹脂や活性炭等を用いる方法の他、（ｉ）金属キレート能を持つ吸着剤を用いる方法（例えば、特許文献１、２）や、（ｉｉ）還元剤を担持させた多孔質担体を用いる方法（例えば、特許文献３）、（ｉｉｉ）微生物を用いた方法（例えば、特許文献４〜６）、（ｉｖ）水素吸蔵合金により還元し、金属微粒子を得る方法（例えば、特許文献７）が知られている。
2. Description of the Related Art Conventionally, metals are widely recovered from solutions containing metals such as industrial wastewater and leachable noble liquids for the purpose of reusing resources in addition to the purpose of satisfying legal water quality standards.
In particular, metal recovery from a metal-containing solution containing a low concentration metal to be recovered includes a method using an ion-exchange resin, activated carbon or the like, and (i) a method using an adsorbent having a metal chelating ability (for example, Patent Document 1). 2), (ii) a method using a porous carrier carrying a reducing agent (for example, Patent Document 3), (iii) a method using a microorganism (for example, Patent Documents 4 to 6), (iv) hydrogen A method (for example, Patent Document 7) in which metal fine particles are obtained by reduction with an occlusion alloy is known.
しかし、イオン交換樹脂や活性炭等を用いる方法の他、前記（ｉ）記載の方法、及び前記（ｉｉ）記載の方法では、これら吸着担体が、高価あるいは担体の製造工程が煩雑であることや、担体からの金属回収工程が煩雑であるという問題がある。
また、前記（ｉｉｉ）記載の方法においては、培養等により金属を捕捉する能力を持つ微生物を調製する工程が煩雑であることや、微生物から目的の金属を回収する際に、微生物自身が持つ金属分との分離が必要であるという問題がある。
さらに、前記（ｉｖ）記載の方法においては、水素吸蔵合金が高価であること、また、目的の金属を回収する際に、水素吸蔵合金との分離が必要であるという問題があった。
However, in addition to the method using ion exchange resin, activated carbon, etc., in the method described in (i) and the method described in (ii), these adsorption carriers are expensive or the manufacturing process of the carrier is complicated, There is a problem that the metal recovery process from the support is complicated.
In the method described in (iii), the process of preparing a microorganism capable of capturing a metal by culturing or the like is complicated, and the metal possessed by the microorganism itself is collected when the target metal is recovered from the microorganism. There is a problem that separation from minutes is necessary.
Furthermore, the method described in (iv) has a problem that the hydrogen storage alloy is expensive, and that the target metal needs to be separated from the hydrogen storage alloy when the target metal is recovered.
産業において有用な金属資源を含有する溶液からの金属回収方法として、上記の通り種々の方法が検討されているが、これらの方法は、金属を捕捉する担体又は微生物の調製工程や、担体又は微生物からの金属回収工程が煩雑であり、必ずしも経済的に満足できるものではなかった。
本発明は、このような従来の課題を解決することを目的とする。
As described above, various methods have been studied as methods for recovering metals from solutions containing metal resources useful in the industry. These methods include steps for preparing carriers or microorganisms for capturing metals, carriers or microorganisms. The metal recovery process was complicated and was not always economically satisfactory.
An object of the present invention is to solve such a conventional problem.
本発明は、簡便に、高い回収効率で、金属含有溶液から金属を回収できる金属回収方法、及び金属回収装置を提供する。 The present invention provides a metal recovery method and a metal recovery apparatus that can recover metal from a metal-containing solution simply and with high recovery efficiency.
すなわち、本発明は、下記の態様を有する。
［１］ 下記工程（１）及び（２）を含む、金属イオンを含有する溶液中からの金属回収方法。
（１）金属イオン含有溶液に水溶性還元剤を作用させて、金属イオンを還元し、金属微粒子とする、還元工程；
（２）前記工程（１）で得られる金属微粒子を含む溶液を、濾過膜により濃縮して、濃縮液を得る、濃縮工程；
［２］ さらに、下記工程（３）を含む、前記態様［１］に記載の金属回収方法。
（３）前記工程（２）で得られる濃縮液を、前記工程（１）に戻す、返送工程；
［３］ 前記工程（１）において、さらに２価鉄イオンを作用させる、前記態様［１］又は［２］に記載の金属回収方法。
［４］ 前記工程（１）において、前記金属イオンを還元させてなる金属を予め含有させる、前記態様［１］〜［３］の何れか一項に記載の金属回収方法。
［５］ 前記金属イオンがＡｕ、Ａｇ、Ｐｔ、Ｐｄ、Ｒｈ、Ｉｒ、Ｒｕ及びＯｓからなる群から選ばれる１以上の元素のイオンである、前記態様［１］〜［４］の何れか一項に記載の金属回収方法。
［６］ 前記水溶性還元剤が、炭素数１〜５の脂肪族アルデヒドである、前記態様［１］〜［５］の何れか一項に記載の金属回収方法。
［７］ 前記炭素数１〜５の脂肪族アルデヒドが、蟻酸及び／又はその塩である、前記態様［６］記載の金属回収方法。
［８］ 下記（ａ）及び（ｂ）を含む、金属回収装置。
（ａ）金属イオンを含有する溶液に、水溶性還元剤を作用させて得られる、金属微粒子を含む液を貯留する、貯留部；
（ｂ）前記工程（ａ）の、該金属微粒子を含む液を、濾過膜により濃縮する、濃縮部；
［９］ さらに、下記工程（ｃ）を含む、前記態様［８］に記載の金属回収装置。
（ｃ）前記工程（ｂ）で得られる濃縮液を、前記工程（ａ）に返送する、返送部；
That is, this invention has the following aspect.
[1] A method for recovering a metal from a solution containing metal ions, comprising the following steps (1) and (2).
(1) A reduction step in which a water-soluble reducing agent is allowed to act on a metal ion-containing solution to reduce metal ions to form metal fine particles;
(2) A concentration step of concentrating the solution containing the metal fine particles obtained in the step (1) with a filtration membrane to obtain a concentrated solution;
[2] The metal recovery method according to the aspect [1], further including the following step (3).
(3) A returning step of returning the concentrate obtained in the step (2) to the step (1);
[3] The metal recovery method according to the aspect [1] or [2], wherein in the step (1), divalent iron ions are further allowed to act.
[4] The metal recovery method according to any one of the aspects [1] to [3], wherein in the step (1), a metal obtained by reducing the metal ion is previously contained.
[5] Any one of the above aspects [1] to [4], wherein the metal ion is an ion of one or more elements selected from the group consisting of Au, Ag, Pt, Pd, Rh, Ir, Ru, and Os. The metal recovery method according to item.
[6] The metal recovery method according to any one of [1] to [5], wherein the water-soluble reducing agent is an aliphatic aldehyde having 1 to 5 carbon atoms.
[7] The metal recovery method according to the above aspect [6], wherein the aliphatic aldehyde having 1 to 5 carbon atoms is formic acid and / or a salt thereof.
[8] A metal recovery apparatus including the following (a) and (b).
(A) A storage unit for storing a liquid containing metal fine particles obtained by allowing a water-soluble reducing agent to act on a solution containing metal ions;
(B) A concentration unit that concentrates the liquid containing the metal fine particles in the step (a) with a filtration membrane;
[9] The metal recovery apparatus according to the aspect [8], further including the following step (c).
(C) A return unit that returns the concentrate obtained in the step (b) to the step (a);
本発明の金属回収方法及び／又は金属回収装置を用いれば、簡便に、高い効率で金属イオン含有溶液から金属微粒子を回収できる。 By using the metal recovery method and / or metal recovery apparatus of the present invention, metal fine particles can be easily recovered from a metal ion-containing solution with high efficiency.
＜金属回収方法＞
本発明は、下記工程（１）及び（２）を含む、金属イオンを含有する溶液中からの金属回収方法である。
（１）金属イオン含有溶液に水溶性還元剤を作用させて、金属イオンを還元し金属微粒子とする、還元工程；
（２）前記工程（１）で得られる金属微粒子を含む溶液を、濾過膜により濃縮して、濃縮液を得る、濃縮工程；
中でも、該金属イオンを還元させてなる金属が、還元反応を触媒する場合、さらに、下記工程（３）を有することが好ましい。
（３）前記工程（２）で得られる濃縮液を、前記工程（１）に戻す、返送工程；
また、前記工程（１）において、さらに、２価鉄イオンを作用させることが、還元反応をより促進させる点から好ましい。
また、前記工程（１）において、該金属イオンを還元させてなる金属を共存させておくことが、還元反応をより促進させる点から好ましい。
前記金属イオンは、特に限定されないが、被還元性に富む観点から、Ａｕ、Ａｇ、Ｐｔ、Ｐｄ、Ｒｈ、Ｉｒ、Ｒｕ及びＯｓからなる群から選ばれる１以上の元素のイオンであることが好ましい。
<Metal recovery method>
The present invention is a method for recovering a metal from a solution containing metal ions, which includes the following steps (1) and (2).
(1) A reduction process in which a water-soluble reducing agent is allowed to act on a metal ion-containing solution to reduce metal ions to form metal fine particles;
(2) A concentration step of concentrating the solution containing the metal fine particles obtained in the step (1) with a filtration membrane to obtain a concentrated solution;
Among these, when the metal formed by reducing the metal ion catalyzes the reduction reaction, it is preferable that the following step (3) is further included.
(3) A returning step of returning the concentrate obtained in the step (2) to the step (1);
Moreover, in the said process (1), it is preferable to make a bivalent iron ion act from the point which accelerates | stimulates a reductive reaction more.
In the step (1), it is preferable to coexist a metal obtained by reducing the metal ion from the viewpoint of further promoting the reduction reaction.
The metal ion is not particularly limited, but is preferably an ion of one or more elements selected from the group consisting of Au, Ag, Pt, Pd, Rh, Ir, Ru, and Os from the viewpoint of high reducibility. .
（水溶性還元剤）
本発明における還元剤は、水溶性の還元剤である。ここで、水溶性とは、常温・中性の水に対し１００ｍｇ／Ｌ以上溶解するもの意味する。
前記還元剤としては、水溶性であり、目的とする金属イオンを還元できる能力があるものであれば特に限定されないが、例えば、次亜リン酸類、亜リン酸類、ヒドラジン類、ヒドロキノン類、炭素数１〜５の脂肪族アルデヒド等がある。
(Water-soluble reducing agent)
The reducing agent in the present invention is a water-soluble reducing agent. Here, the term “water-soluble” means that 100 mg / L or more dissolves in normal temperature / neutral water.
The reducing agent is not particularly limited as long as it is water-soluble and capable of reducing the target metal ion. For example, hypophosphorous acids, phosphorous acids, hydrazines, hydroquinones, carbon number 1-5 aliphatic aldehydes and the like.
前記次亜リン酸類として例えば、次亜リン酸、次亜リン酸ナトリウム（一水和物）、次亜リン酸アンモニウム等が挙げられる。
また、亜リン酸類として具体的には、亜リン酸、亜リン酸水素ナトリウム、亜リン酸二カリウム等が挙げられる。
ヒドラジン類としては、ヒドラジン；硫酸ヒドラジン、塩酸ヒドラジン等のヒドラジン塩；ピラゾール類、トリアゾール類、ヒドラジド類等のヒドラジン誘導体等が挙げられる。これらの内で、ピラゾール類としては、ピラゾールの他に、３，５−ジメチルピラゾール、３−メチル−５−ピラゾロン等のピラゾール誘導体が挙げられる。トリアゾール類としては、４−アミノ−１，２，４−トリアゾール、１，２，３−トリアゾール等を用いることができる。ヒドラジド類としては、アジピン酸ヒドラジド、マレイン酸ヒドラジド等が挙げられる。
ヒドロキノン類としては、ヒドロキノン並びにその塩、カテコール並びにその塩、レゾルシノール並びにその塩、ナフトヒドロキノン並びにその塩、アントラヒドロキノン並びにその塩、及びこれらの置換異性体等が挙げられる。
炭素数１〜５の脂肪族アルデヒドとしては、蟻酸及び／又はその塩、ホルムアルデヒド、アセトアルデヒド、プロピオンアルデヒド、ブチルアルデヒド、イソブチルアルデヒド、バレルアルデヒド、イソバレルアルデヒド等が挙げられる。
これらの還元剤は、一種単独で用いてもよく、２種以上組み合せて用いてもよい。
特に、安価かつ生分解性に優れることから、炭素数１〜５の脂肪族アルデヒドが好ましく、炭素数１〜３の脂肪族アルデヒドがより好ましく、蟻酸及び／又はその塩の水溶液がさらに好ましい。
Examples of the hypophosphorous acid include hypophosphorous acid, sodium hypophosphite (monohydrate), ammonium hypophosphite and the like.
Specific examples of phosphorous acids include phosphorous acid, sodium hydrogen phosphite, and dipotassium phosphite.
Examples of the hydrazines include hydrazine; hydrazine salts such as hydrazine sulfate and hydrazine hydrochloride; hydrazine derivatives such as pyrazoles, triazoles and hydrazides. Among these, examples of pyrazoles include pyrazole derivatives such as 3,5-dimethylpyrazole and 3-methyl-5-pyrazolone in addition to pyrazole. As triazoles, 4-amino-1,2,4-triazole, 1,2,3-triazole and the like can be used. Examples of hydrazides include adipic hydrazide and maleic hydrazide.
Examples of hydroquinones include hydroquinone and its salts, catechol and its salts, resorcinol and its salts, naphthohydroquinone and its salts, anthrahydroquinone and its salts, and substituted isomers thereof.
Examples of the aliphatic aldehyde having 1 to 5 carbon atoms include formic acid and / or a salt thereof, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, valeraldehyde, and isovaleraldehyde.
These reducing agents may be used alone or in combination of two or more.
In particular, an aliphatic aldehyde having 1 to 5 carbon atoms is preferable, an aliphatic aldehyde having 1 to 3 carbon atoms is more preferable, and an aqueous solution of formic acid and / or a salt thereof is more preferable because it is inexpensive and excellent in biodegradability.
＜金属回収装置＞
本発明の金属回収装置は、下記（ａ）及び（ｂ）を含む。
（ａ）金属イオンを含有する溶液に、水溶性還元剤を作用させて得られる、金属微粒子を含む液を貯留する、貯留部；
（ｂ）前記工程（ａ）の、該金属微粒子を含む液を、濾過膜により濃縮する、濃縮部；
<Metal recovery device>
The metal recovery apparatus of the present invention includes the following (a) and (b).
(A) A storage unit for storing a liquid containing metal fine particles obtained by allowing a water-soluble reducing agent to act on a solution containing metal ions;
(B) A concentration unit that concentrates the liquid containing the metal fine particles in the step (a) with a filtration membrane;
該金属イオンを還元させてなる金属が、還元反応を触媒する場合、本発明の金属回収装置は、下記工程（ｃ）をさらに含むことが、還元反応をより促進させる点から好ましい。
（ｃ）前記工程（ｂ）で得られる濃縮液を、前記工程（ａ）に返送する、返送部；
When the metal obtained by reducing the metal ions catalyzes the reduction reaction, it is preferable that the metal recovery apparatus of the present invention further includes the following step (c) from the viewpoint of further promoting the reduction reaction.
(C) A return unit that returns the concentrate obtained in the step (b) to the step (a);
前記構成について、説明する。
＜（ａ）貯留部＞
（ａ）貯留部：反応液貯留槽１０には、金属イオン含有溶液貯留槽２０から配管５０を通じて金属イオン含有溶液Ｗ０が供給され、還元剤貯留槽２４から配管５４を通じて水溶性還元剤（以下、還元剤Ｂとも言う）が供給される。供給された金属イオン含有溶液Ｗ０、及び還元剤Ｂは、撹拌翼１０ａによって撹拌混合され、該金属イオン含有溶液Ｗ０中の金属イオンが還元され金属微粒子が生成する。反応液貯留槽１０の材質は、金属含有溶液Ｗ０、還元剤Ｂにより腐食され難く、還元剤の作用に悪影響を与えないものであればよく、公知のものを採用できる。
The configuration will be described.
<(A) Reservoir>
(A) Storage part: The reaction liquid storage tank 10 is supplied with the metal ion-containing solution W 0 from the metal ion-containing solution storage tank 20 through the pipe 50 and is supplied with a water-soluble reducing agent (hereinafter referred to as “reducing agent”) , Also referred to as reducing agent B). The supplied metal ion-containing solution W 0 and the reducing agent B are stirred and mixed by the stirring blade 10a, and the metal ions in the metal ion-containing solution W 0 are reduced to generate metal fine particles. The material of the reaction liquid storage tank 10 may be any material as long as it is not easily corroded by the metal-containing solution W 0 and the reducing agent B and does not adversely affect the action of the reducing agent.
＜（ｂ）濃縮部＞
（ｂ）濃縮部：濾過膜を有する膜モジュール１４には、反応液貯留槽１０から配管５６を通じて金属微粒子含有溶液Ｗ１が供給される。膜モジュール１４内の濾過膜の二次側（濾過水側）１４ｂが配管４６を通じて濾過ポンプ４８と接続されており、濾過ポンプ４８が稼働することで濾過膜の一次側１４ａから金属微粒子を含有する濃縮液Ｗ２が、二次側１４ｂから濾過水Ｗ３が得られる。
<(B) Concentration part>
(B) concentrating unit: a membrane module 14 having a filtration membrane, the metal fine particle-containing solution W 1 is supplied through the pipe 56 from the reaction liquid reservoir 10. The secondary side (filtered water side) 14b of the filtration membrane in the membrane module 14 is connected to the filtration pump 48 through the pipe 46, and the filtration pump 48 operates to contain metal fine particles from the primary side 14a of the filtration membrane. Concentrated liquid W 2 is obtained from filtered water W 3 from the secondary side 14b.
濾過膜としては、金属微粒子を捕捉できるものであれば特に制限されず、中空糸膜、平膜、チューブラ膜、モノリス型膜等、公知のものを使用できる。なかでも、濾過膜としては、容積充填率が高いことから、中空糸膜が好ましい。
濾過膜の材質としては、金属微粒子含有溶液Ｗ１により腐食されないものであれば、特に制限されず、セラミック等の無機膜、セルロース、セルロース混合エステル、ポリオレフィン、ポリスルホン、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリ四フッ化エチレン（ＰＴＦＥ）等の有機膜を使用できる。なかでも、耐薬品性やｐＨ変化に強い点から、セラミック、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリ四フッ化エチレン（ＰＴＦＥ）が好ましい。
The filtration membrane is not particularly limited as long as it can capture metal fine particles, and a known membrane such as a hollow fiber membrane, a flat membrane, a tubular membrane, or a monolith type membrane can be used. Among these, a hollow fiber membrane is preferable as the filtration membrane because of its high volume filling rate.
The material of the filtration membrane, as long as it is not corroded by the metal fine particle-containing solution W 1, not particularly limited, inorganic membranes such as ceramics, cellulose, cellulose mixed ester, polyolefin, polysulfone, polyvinylidene fluoride (PVDF), poly An organic film such as tetrafluoroethylene (PTFE) can be used. Among these, ceramic, polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE) are preferable from the viewpoint of resistance to chemical resistance and pH change.
濾過膜に形成される微細孔の平均孔径は、金属微粒子を捕捉できれば特に制限されないが、０．０１〜１．０μｍが好ましく、０．０５〜０．４μｍがより好ましい。
ここで、前記微細孔の平均孔径が下限値以上であれば、膜濾過に要する圧力を小さくしやすく、また微粒子の濃縮効率を高くしやすい。
また、前記微細孔の平均孔径が上限値以下であれば、金属微粒子の濾過膜の二次側への漏出を抑制しやすい。
The average pore diameter of the micropores formed in the filtration membrane is not particularly limited as long as the metal fine particles can be captured, but is preferably 0.01 to 1.0 μm, and more preferably 0.05 to 0.4 μm.
Here, if the average pore diameter of the micropores is not less than the lower limit value, the pressure required for membrane filtration can be easily reduced and the concentration efficiency of the fine particles can be easily increased.
Moreover, if the average pore diameter of the micropores is equal to or less than the upper limit value, it is easy to suppress leakage of metal fine particles to the secondary side of the filtration membrane.
＜（ｃ）返送部＞
（ｃ）返送部：前記膜モジュール１４において、濾過膜の一次側１４ａから得られる、金属微粒子を含有する濃縮液Ｗ２は、配管５８を通じて反応液貯留槽１０に返送される。金属微粒子が金属イオンの還元剤による還元を触媒する場合、反応液貯留槽１０中の金属微粒子濃度が高くなることで、反応効率を高めることができる。
<(C) Return part>
(C) Return part: In the membrane module 14, the concentrated liquid W 2 containing metal fine particles obtained from the primary side 14 a of the filtration membrane is returned to the reaction liquid storage tank 10 through the pipe 58. When the metal fine particles catalyze the reduction of the metal ions by the reducing agent, the reaction efficiency can be increased by increasing the concentration of the metal fine particles in the reaction liquid storage tank 10.
本発明は、前記工程（ａ）の前に、下記工程（ａ´）を含んでいてもよい。
＜（（ａ´）供給部＞
（ａ´）供給部：金属含有溶液貯留槽２０は、金属イオン含有溶液Ｗ０を一旦貯留する貯留槽である。金属含有溶液貯留槽２０は、金属含有溶液Ｗ０を貯留できるものであれば、特に限定されない。
還元剤貯留槽２４は、金属含有溶液Ｗ０に含まれる金属イオンを還元し金属微粒子とする際に必要な還元剤Ｂを一旦貯留する手段である。還元剤貯留槽２４は、還元剤Ｂを貯留できるものであれば、特に限定されない。
金属含有溶液貯留槽２０と反応液貯留槽１０とが、配管５０で接続されており、また、還元剤貯留槽２４と反応液貯留槽１０とが、配管５４で接続されている。
The present invention may include the following step (a ′) before the step (a).
<((A ′) supply section>
(A ′) Supply unit: The metal-containing solution storage tank 20 is a storage tank that temporarily stores the metal ion-containing solution W 0 . Metal-containing solution storage tank 20, as long as it can store the metal-containing solution W 0, not particularly limited.
The reducing agent reservoir 24 is means for temporarily storing the reducing agent B necessary for the reduction of the metal ions contained in the metal-containing solution W 0 metal particles. The reducing agent storage tank 24 is not particularly limited as long as it can store the reducing agent B.
The metal-containing solution storage tank 20 and the reaction liquid storage tank 10 are connected by a pipe 50, and the reducing agent storage tank 24 and the reaction liquid storage tank 10 are connected by a pipe 54.
金属回収装置１は、上記（ａ）〜（ｃ）（又は、（ａ´）〜（ｃ））の他、回収部１６：反応液貯留槽１０から配管４４を通じて送られてくる、金属微粒子含有濃縮溶液Ｗ１を回収する部分、及び、濾過水貯留槽１８：膜モジュール１４の濾過膜を透過した濾過水Ｗ３を貯留する部分、を含んでいてもよい。
回収部１６は、金属微粒子含有溶液Ｗ１を回収できるものであれば特に限定されない。
In addition to the above (a) to (c) (or (a ′) to (c)), the metal recovery apparatus 1 includes a recovery unit 16: metal fine particles that are sent from the reaction liquid storage tank 10 through the pipe 44. portion for recovering the concentrated solution W 1, and, the filtered water storage tank 18: a portion for storing filtered water W 3 having passed through the filtration membrane of the membrane module 14, may be included.
Recovery unit 16 is not particularly limited as long as it can collect the fine metal particles-containing solution W 1.
濾過水貯留槽１８は、濾過水Ｗ３を貯留できるものであれば特に限定されない。
濾過水貯留槽１８は、必要に応じて、濾過水Ｗ３のｐＨを河川等への放流に適した調整するｐＨ調整手段を有していてもよい。
前記ｐＨ調整手段としては、濾過水Ｗ３のｐＨを所望のｐＨに調整できるものであればよく、ｐＨ計と、酸添加装置及びアルカリ添加装置とを備えた手段等が挙げられる。
The filtered water storage tank 18 is not particularly limited as long as the filtered water W 3 can be stored.
The filtered water storage tank 18 may have a pH adjusting unit that adjusts the pH of the filtered water W 3 to be suitable for discharge to a river or the like as necessary.
The pH adjusting means may be any means as long as the pH of the filtered water W 3 can be adjusted to a desired pH, and examples thereof include a pH meter, an acid addition device, and an alkali addition device.
金属回収装置１では、金属含有溶液貯留槽２０から金属イオン含有溶液Ｗ０、還元剤貯留槽２４から還元剤Ｂがそれぞれ反応液貯留槽１０に供給される。このとき、還元反応効率を向上させる点で、反応液貯留槽１０内に該金属イオンを還元させてなる金属を共存させておくことが好ましい。
また、反応液貯留槽１０で金属イオン含有溶液Ｗ０に含まれる金属イオンを還元剤により還元して得られた金属微粒子含有溶液Ｗ１の一部が膜モジュール１４が有する濾過膜により濾過され、金属微粒子を含む溶液が濃縮されて、該金属微粒子含有濃縮溶液Ｗ２（濃縮液）が反応液貯留槽１０に返送されることにより、反応液貯留槽１０内の金属微粒子含有溶液Ｗ１の金属微粒子濃度が上昇する。所望の濃度に上昇した金属微粒子含有溶液Ｗ１は、回収部１６に回収することができる。
濾過膜により濾過された濾過水Ｗ３は、濾過水貯留槽１８で必要に応じてｐＨが調整されて放流される。
In the metal recovery apparatus 1, the metal ion-containing solution W 0 is supplied from the metal-containing solution storage tank 20, and the reducing agent B is supplied from the reducing agent storage tank 24 to the reaction liquid storage tank 10. At this time, it is preferable that a metal obtained by reducing the metal ions coexist in the reaction liquid storage tank 10 in terms of improving the reduction reaction efficiency.
In addition, a part of the metal fine particle-containing solution W 1 obtained by reducing the metal ions contained in the metal ion-containing solution W 0 with the reducing agent in the reaction liquid storage tank 10 is filtered by the filtration membrane of the membrane module 14, The solution containing the metal fine particles is concentrated, and the metal fine particle-containing concentrated solution W 2 (concentrated liquid) is returned to the reaction liquid storage tank 10, whereby the metal of the metal fine particle-containing solution W 1 in the reaction liquid storage tank 10. The fine particle concentration increases. The metal fine particle-containing solution W 1 that has risen to a desired concentration can be recovered by the recovery unit 16.
The filtered water W 3 filtered by the filtration membrane is discharged in the filtered water storage tank 18 with the pH adjusted as necessary.
以上説明した本発明の金属回収装置にあっては、金属イオン含有溶液中の金属イオンを還元剤により還元して得られた金属微粒子を含む溶液の一部を濃縮部に移して該微粒子を濾過膜による濾過して濃縮し、該微粒子を含む濃縮液を得る。そのため、金属イオン含有溶液から高い効率で連続的に金属を回収できる。 In the metal recovery apparatus of the present invention described above, a part of the solution containing metal fine particles obtained by reducing metal ions in a metal ion-containing solution with a reducing agent is transferred to a concentration section, and the fine particles are filtered. Filtration through a membrane and concentration to obtain a concentrated solution containing the fine particles. Therefore, metal can be continuously recovered from the metal ion-containing solution with high efficiency.
なお、本発明の金属回収装置は、前記した金属回収装置１には限定されない。
例えば、本発明の金属回収装置は、反応液貯留槽中に、濾過膜を有する膜モジュールが直接浸漬された状態で膜濾過を行える装置でもよい。
The metal recovery apparatus of the present invention is not limited to the metal recovery apparatus 1 described above.
For example, the metal recovery apparatus of the present invention may be an apparatus that can perform membrane filtration in a state where a membrane module having a filtration membrane is directly immersed in a reaction liquid storage tank.
また、金属イオン含有溶液中の金属イオンを還元剤により還元し金属微粒子を得る反応を、反応液貯留槽以前の配管内で行う装置でもよく、反応液貯留槽以前に反応槽を設けた装置でもよい。該還元反応を行う際、還元反応効率を向上させる点で、２価鉄イオンをさらに作用させることが好ましい。２価鉄イオンの形態は特に限定されないが、水溶性の塩、又は、その水溶液の形が好ましい。２価鉄の水溶性の塩としては、特に限定されないが、硫酸鉄（ＩＩ）、塩化鉄（ＩＩ）、酢酸鉄（ＩＩ）、硫酸アンモニウム鉄（ＩＩ）等が挙げられ、硫酸鉄（ＩＩ）、塩化鉄（ＩＩ）が好ましい。また、金属微粒子が金属イオンの還元剤による還元を触媒する場合、還元反応効率を向上させる点で、反応液貯留槽内に該金属イオンを還元させてなる金属を共存させておくことが好ましい。 Moreover, the apparatus which performs the reaction which reduce | restores the metal ion in a metal ion containing solution with a reducing agent, and obtains metal microparticles in piping before a reaction liquid storage tank may be used, or the apparatus which provided the reaction tank before the reaction liquid storage tank Good. When carrying out the reduction reaction, it is preferable to further act divalent iron ions in terms of improving the reduction reaction efficiency. The form of the divalent iron ion is not particularly limited, but a water-soluble salt or an aqueous solution thereof is preferable. Although it does not specifically limit as a water-soluble salt of divalent iron, Iron sulfate (II), Iron chloride (II), Iron acetate (II), Ammonium iron sulfate (II), etc. are mentioned, Iron (II) sulfate, Iron (II) chloride is preferred. Further, when the metal fine particles catalyze the reduction of the metal ions by the reducing agent, it is preferable that a metal obtained by reducing the metal ions coexists in the reaction liquid storage tank in order to improve the reduction reaction efficiency.
また、濾過水中に還元剤が残存する場合、例えば逆浸透膜等の残存する還元剤を濃縮できるような膜と、その濃縮された還元剤を含む水溶液を反応液貯留槽、又は、還元剤貯留槽に返送する返送ラインとを設け、濾過水に残存した還元剤を回収して利用する装置としてもよい。 When the reducing agent remains in the filtered water, for example, a membrane capable of concentrating the remaining reducing agent, such as a reverse osmosis membrane, and an aqueous solution containing the concentrated reducing agent are stored in a reaction liquid storage tank or a reducing agent reservoir. It is good also as an apparatus which provides the return line which returns to a tank, and collects and uses the reducing agent which remained in filtered water.
＜金属回収方法＞
以下、本発明の金属回収方法の一例として、前記した金属回収装置１を用いた方法について説明する。
金属回収装置１を用いた金属回収方法では、反応液貯留槽１０に金属イオン含有溶液Ｗ０、還元剤Ｂを供給し、反応液貯留槽１０において、金属イオン含有溶液Ｗ０に還元剤Ｂを作用させ、金属イオン含有溶液Ｗ０中の金属イオンを該還元剤により還元して得られた金属微粒子含有溶液Ｗ１を濃縮部１４に移す。
具体的には、撹拌翼１０ａで撹拌しつつ、反応液貯留槽１０に、金属イオン含有溶液貯留槽２０から配管５０を通じて金属イオン含有溶液Ｗ０を供給し、還元剤貯留槽２４から還元剤Ｂを供給する。
また、反応液貯留槽１０内において金属イオン含有溶液中の金属イオンを還元剤Ｂにより還元し金属微粒子とし、金属微粒子含有溶液Ｗ１の一部を、配管４２を通じて濃縮部１４に移していく。
<Metal recovery method>
Hereinafter, a method using the above-described metal recovery apparatus 1 will be described as an example of the metal recovery method of the present invention.
Metal recovery apparatus in the metal recovery method using 1, reaction metal ions contained in the reservoir 10 solution W 0, to supply the reducing agent B, in the reaction solution reservoir 10, the reducing agent B in the metal ion-containing solution W 0 The metal fine particle-containing solution W 1 obtained by reducing the metal ions in the metal ion-containing solution W 0 with the reducing agent is transferred to the concentration unit 14.
Specifically, the metal ion-containing solution W 0 is supplied from the metal ion-containing solution storage tank 20 through the pipe 50 to the reaction liquid storage tank 10 while being stirred by the stirring blade 10 a, and the reducing agent B is supplied from the reducing agent storage tank 24. Supply.
Further, in the reaction liquid storage tank 10, metal ions in the metal ion-containing solution are reduced by the reducing agent B to form metal fine particles, and a part of the metal fine particle-containing solution W 1 is transferred to the concentration unit 14 through the pipe 42.
本実施形態に用いる還元剤は、水溶性であり、目的とする金属イオンを金属に還元できる能力があるものであれば特に限定されないが、安価かつ生分解性に優れることから炭素数１〜５の脂肪族アルデヒドが好ましく使用され、蟻酸及び／又はその塩が特に好ましく使用される。
Ａｕ、Ａｇ、Ｐｔ、Ｐｄ、Ｒｈ、Ｉｒ、Ｒｕ及びＯｓからなる群から選ばれる１以上の元素、いわゆる貴金属と呼ばれる金属のイオンは還元され金属微粒子となる。そのため、金属含有溶液Ｗ０中の金属イオンを金属微粒子として回収できる。
The reducing agent used in the present embodiment is not particularly limited as long as it is water-soluble and has the ability to reduce the target metal ion to a metal. However, since it is inexpensive and excellent in biodegradability, it has 1 to 5 carbon atoms. Are preferably used, and formic acid and / or a salt thereof are particularly preferably used.
One or more elements selected from the group consisting of Au, Ag, Pt, Pd, Rh, Ir, Ru, and Os, so-called noble metal ions, are reduced to form fine metal particles. Therefore, the metal ion of the metal-containing solution W in 0 can be recovered as the metal microparticles.
金属イオン含有溶液Ｗ０、還元剤Ｂの反応液貯留槽１０への供給量比は、反応液貯留槽１０内における金属イオン及び還元剤Ｂの理論的初期濃度が、金属イオンが還元剤により還元し金属微粒子とするのに適した条件となるようにすればよい。
なお、理論的初期濃度とは、未反応である場合の反応液中の金属イオン含有溶液Ｗ０、還元剤Ｂの濃度を示す。
反応液貯留槽１０の反応液中の金属イオンの理論的初期濃度は、金属イオンが溶解していることが還元反応効率がより良好になる点から、０．０１〜１０ｍＭが好ましく、０．１〜５ｍＭがより好ましい。
反応液貯留槽１０の反応液中の還元剤Ｂの理論的初期濃度は、金属イオンを還元剤により還元し金属微粒子とする効率がより良好になる点から、０．２〜２００ｍＭが好ましく、１〜５０ｍＭがより好ましい。
The supply amount ratio of the metal ion-containing solution W 0 and the reducing agent B to the reaction liquid storage tank 10 is such that the theoretical initial concentration of the metal ions and the reducing agent B in the reaction liquid storage tank 10 is reduced by the reducing agent. However, the conditions should be suitable for forming metal fine particles.
The theoretical initial concentration refers to the concentration of the metal ion-containing solution W 0 and the reducing agent B in the reaction solution when not reacted.
The theoretical initial concentration of the metal ions in the reaction solution in the reaction solution storage tank 10 is preferably 0.01 to 10 mM from the viewpoint that the reduction reaction efficiency is better when the metal ions are dissolved. ˜5 mM is more preferred.
The theoretical initial concentration of the reducing agent B in the reaction liquid in the reaction liquid storage tank 10 is preferably 0.2 to 200 mM from the viewpoint that the efficiency of reducing metal ions with the reducing agent to form metal fine particles is better. ˜50 mM is more preferred.
反応液貯留槽１０の反応液のｐＨは、特に制限されず、金属イオン含有溶液Ｗ０、還元剤Ｂの性状により好適な値を取ることができるが、金属水酸化物の沈殿を避ける観点から７以下が好ましく、５以下がより好ましい。ｐＨの下限については特に制限されないが、取扱い時の安全性や装置への腐食の影響を避ける観点から０以上が好ましい。
反応液貯留槽１０の反応液の温度は、特に制限されず、金属イオン含有溶液Ｗ０、還元剤Ｂの性状により好適な値を取ることができるが、０〜１００℃とすることが好ましく、２０〜１００℃がより好ましい。
また、反応液貯留槽１０には、還元反応効率を向上させる点で、さらに、２価鉄イオンを作用させることが好ましい。
２価鉄イオンを作用させる時期は特に限定されないが、還元反応の効率をより高める観点から、金属イオン含有溶液Ｗ０、還元剤Ｂを供給する前、又は、供給開始直後に作用させることが好ましい。
２価鉄イオンを作用させる濃度は還元反応効率がより良好になる点から、１質量ｐｐｍ以上が好ましく、５質量ｐｐｍ以上がより好ましく、２０質量ｐｐｍ以上がさらに好ましい。濃度の上限については特に限定されないが、３価鉄の沈殿が混入することによる回収金属の品位低下を防ぐ観点から、１００質量ｐｐｍ以下とすることが好ましい。金属微粒子が金属イオンの還元剤による還元を触媒する場合、２価鉄イオンをさらに作用させることにより、目的の金属イオンが還元されて金属微粒子が生成された後は、２価鉄イオンを作用させなくてもよい。
The pH of the reaction solution in the reaction solution storage tank 10 is not particularly limited, and can take a suitable value depending on the properties of the metal ion-containing solution W 0 and the reducing agent B, but from the viewpoint of avoiding the precipitation of the metal hydroxide. 7 or less is preferable and 5 or less is more preferable. The lower limit of the pH is not particularly limited, but is preferably 0 or more from the viewpoint of safety during handling and avoiding the influence of corrosion on the apparatus.
The temperature of the reaction liquid in the reaction liquid storage tank 10 is not particularly limited, and can take a more suitable value depending on the properties of the metal ion-containing solution W 0 and the reducing agent B, but is preferably 0 to 100 ° C., 20-100 degreeC is more preferable.
Moreover, it is preferable to make a bivalent iron ion act on the reaction liquid storage tank 10 at the point which improves a reduction reaction efficiency.
Divalent iron timing the action of the ion is not particularly limited, from the viewpoint of enhancing the efficiency of the reduction reaction, the metal ion-containing solution W 0, before supplying the reducing agent B, or, it is preferable to act immediately after the start of supply .
The concentration at which divalent iron ions act is preferably 1 ppm by mass or more, more preferably 5 ppm by mass or more, and even more preferably 20 ppm by mass or more from the viewpoint of better reduction reaction efficiency. The upper limit of the concentration is not particularly limited, but is preferably set to 100 mass ppm or less from the viewpoint of preventing the quality of the recovered metal from deteriorating due to the mixing of trivalent iron precipitates. When the metal fine particles catalyze the reduction of the metal ions by the reducing agent, by further acting the divalent iron ions, the divalent iron ions are allowed to act after the target metal ions are reduced to form the metal fine particles. It does not have to be.
また、反応液貯留槽１０には、還元反応効率を向上させる点で、該金属イオンを還元させてなる金属を共存させておくことが好ましい。金属を共存させる時期は特に限定されないが、還元反応の効率をより高める観点から、金属イオン含有溶液Ｗ０、還元剤Ｂを供給する前、あるいは供給開始直後から共存させておくことが好ましい。
共存させる量についても特に限定されないが、反応液貯留槽１０にて回分反応を行った際の生成量の１％〜２００％とすることが好ましい。
金属の形態についても特に制限されないが、表面積を大きくすることが還元反応効率をより向上させることから、粒子径０．０１μｍ〜１ｍｍとすることが好ましい。
Moreover, it is preferable to coexist the metal which reduces this metal ion with the reaction liquid storage tank 10 at the point which improves reduction reaction efficiency. The timing of coexisting the metal is not particularly limited, but from the viewpoint of further improving the efficiency of the reduction reaction, it is preferable to coexist before supplying the metal ion-containing solution W 0 and the reducing agent B or immediately after starting the supply.
The amount of coexistence is not particularly limited, but is preferably 1% to 200% of the amount produced when batch reaction is performed in the reaction liquid storage tank 10.
The form of the metal is not particularly limited, but it is preferable that the particle diameter be 0.01 μm to 1 mm because increasing the surface area further improves the reduction reaction efficiency.
また、還元工程を半回分反応で行う場合、金属イオン含有溶液Ｗ０、還元剤Ｂの反応液貯留槽１０への供給は、金属微粒子含有溶液Ｗ１の反応液貯留槽１０への送液量を考慮して、反応液貯留槽１０内における反応液が所定量を維持できる範囲で調節する。金属イオン含有溶液Ｗ０、還元剤Ｂの反応液貯留槽１０への供給は、反応液貯留槽１０内における反応液が所定量に維持できれば、連続的であってもよく、断続的であってもよい。 When performing the reduction step in a semi-batch reaction, the metal ion-containing solution W 0, feed to the reaction solution reservoir 10 of the reducing agent B is feed rate to the reaction solution reservoir 10 of the metal fine particle-containing solution W 1 In consideration of the above, the reaction liquid in the reaction liquid storage tank 10 is adjusted within a range in which a predetermined amount can be maintained. The supply of the metal ion-containing solution W 0 and the reducing agent B to the reaction liquid storage tank 10 may be continuous or intermittent as long as the reaction liquid in the reaction liquid storage tank 10 can be maintained at a predetermined amount. Also good.
還元工程を半回分反応で行う場合、反応液貯留槽１０からの金属微粒子含有溶液Ｗ１の濃縮部１４への移液は、反応液貯留槽１０内における反応液の平均滞留時間（ＨＲＴ）が所望の時間となるように調節すればよい。反応液貯留槽１０内の反応液の平均滞留時間（ＨＲＴ）は、金属イオン及び還元剤の前記理論的初期濃度から回分反応を行った場合に所望の還元反応率を達成できる時間とすればよい。 When the reduction step is performed by a half-batch reaction, the transfer of the fine metal particle-containing solution W 1 from the reaction liquid storage tank 10 to the concentration unit 14 has an average residence time (HRT) of the reaction liquid in the reaction liquid storage tank 10. What is necessary is just to adjust so that it may become desired time. The average residence time (HRT) of the reaction liquid in the reaction liquid storage tank 10 may be a time during which a desired reduction reaction rate can be achieved when a batch reaction is performed from the theoretical initial concentrations of metal ions and a reducing agent. .
濃縮部１４においては、反応液貯留槽１０から移した、金属微粒子含有溶液Ｗ１を、濾過ポンプ４８を稼働させて、膜モジュール１４が有する濾過膜によって濾過する。これにより、金属微粒子含有溶液Ｗ１が濃縮される。
膜モジュールの有効膜面積は特に制限されず、濾過ポンプで所望の量の濾過水が得られるような膜面積とすれば良い。濾過ポンプで所望の量の濾過水を得る際に濾過線速度（ＬＶ）が０．１〜１ｍ／日となるような膜面積とすることが、濾過効率が良く、かつ、膜閉塞を防ぐ観点から好ましい。
また、膜濾過により金属微粒子を含む溶液が濃縮されて、該金属微粒子含有濃縮溶液Ｗ２（濃縮液）が反応液貯留槽１０に返送されることにより、反応液貯留槽１０内の金属微粒子含有溶液Ｗ１がの金属微粒子濃度が上昇する。所望の濃度に上昇した金属微粒子含有溶液Ｗ１は、配管４４を通じて回収部１６に回収することができる。
また、濾過膜によって濾過された濾過水Ｗ３は、配管４６を通じて濾過水貯留槽１８に回収して貯留し、必要に応じてｐＨを調整して河川等に放流する。
In the concentration unit 14, the metal fine particle-containing solution W 1 transferred from the reaction solution storage tank 10 is filtered by the filtration membrane of the membrane module 14 by operating the filtration pump 48. Thus, the metal fine particle-containing solution W 1 is concentrated.
The effective membrane area of the membrane module is not particularly limited, and may be a membrane area that allows a desired amount of filtered water to be obtained with a filtration pump. When obtaining a desired amount of filtered water with a filtration pump, the membrane area should have a filtration linear velocity (LV) of 0.1 to 1 m / day, so that the filtration efficiency is good and the membrane is blocked. To preferred.
Further, the solution containing metal fine particles is concentrated by membrane filtration, and the metal fine particle-containing concentrated solution W 2 (concentrated liquid) is returned to the reaction liquid storage tank 10 to contain the metal fine particles in the reaction liquid storage tank 10. metal particle concentration of the solution W 1 increases. The metal fine particle-containing solution W 1 that has risen to a desired concentration can be recovered by the recovery unit 16 through the pipe 44.
Further, the filtered water W 3 filtered by the filtration membrane, and stored in recovered filtered water storage tank 18 through the pipe 46, is discharged into rivers or the like to adjust the pH as needed.
本実施形態の金属回収方法で回収した金属の用途は、特に限定されない。本実施形態では、金属微粒子が凝集された状態となっており、そのままの状態で触媒等として使用できる。
また、金属微粒子を、例えば、電気炉等で焼くことで還元剤等の不純物を取り除いた後に、回収した金属微粒子又は金属塊を使用してもよい。
The use of the metal recovered by the metal recovery method of the present embodiment is not particularly limited. In this embodiment, the metal fine particles are in an aggregated state, and can be used as a catalyst or the like as they are.
Moreover, after removing impurities, such as a reducing agent, by baking metal fine particles with an electric furnace etc., you may use the collect | recovered metal fine particles or metal lump.
以上説明した本発明による金属回収方法にあっては、反応液貯留槽で金属含有溶液に含まれる金属イオンを水溶性還元剤により還元して得られた金属微粒子を含む溶液を膜濾過によって濃縮し、金属微粒子を含む濃縮液を得ることができるため、金属含有溶液から高い効率で金属を回収できる。
また、金属を回収するために吸着剤や微生物を用いる必要がないため、回収後の精製が簡便である。
In the metal recovery method according to the present invention described above, a solution containing metal fine particles obtained by reducing metal ions contained in a metal-containing solution with a water-soluble reducing agent in a reaction liquid storage tank is concentrated by membrane filtration. Since a concentrated liquid containing metal fine particles can be obtained, the metal can be recovered from the metal-containing solution with high efficiency.
Further, since it is not necessary to use an adsorbent or a microorganism to recover the metal, purification after the recovery is simple.
なお、本発明の金属回収方法は、前記した金属回収装置１を用いる方法には限定されない。例えば、反応液貯留槽に、濾過膜を有する膜モジュールが直接浸漬された状態で膜濾過を行える装置を用いた方法であってもよい。 The metal recovery method of the present invention is not limited to the method using the metal recovery apparatus 1 described above. For example, the method using the apparatus which can perform membrane filtration in the state in which the membrane module which has a filtration membrane was directly immersed in the reaction liquid storage tank may be used.
また、金属イオン含有溶液中の金属イオンを、還元剤により還元し金属微粒子とする反応を反応液貯留槽以前の配管内で行う方法でもよく、反応液貯留槽以前に反応槽を設けた装置を用いた方法でもよい。 Moreover, the method of performing the reaction which reduces the metal ion in a metal ion containing solution with a reducing agent, and makes it a metal microparticle in piping before a reaction liquid storage tank may be sufficient, and the apparatus which provided the reaction tank before the reaction liquid storage tank is provided. The method used may be used.
また、濾過水中に還元剤が残存する場合、残存する還元剤を、例えば逆浸透膜等の還元剤を濃縮できるような膜を用いて濃縮し、その濃縮された還元剤を含む水溶液を反応液貯留槽又は還元剤貯留槽に送り、残存した還元剤を回収して利用する方法としてもよい。 When the reducing agent remains in the filtered water, the remaining reducing agent is concentrated using a membrane that can concentrate the reducing agent such as a reverse osmosis membrane, and an aqueous solution containing the concentrated reducing agent is added to the reaction solution. It is good also as a method of sending to a storage tank or a reducing agent storage tank, and collect | recovering and using the remaining reducing agent.
以下、実施例によって本発明を詳細に説明するが、本発明は以下の記載によっては限定されない。 EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description.
［濾過膜］
膜モジュールには、ポリフッ化ビニリデン（ＰＶＤＦ）樹脂からなる複合中空糸膜（外径２．８ｍｍ、公称孔径０．０５μｍ、三菱レイヨン株式会社製）を使用した。
メンブレンフィルターには、セルロース混合エステルからなる膜（ＭＦ−ミリポア、直径４７ｍｍ、公称孔径０．０５μｍ）を使用した。
[Filtration membrane]
A composite hollow fiber membrane (outer diameter 2.8 mm, nominal pore diameter 0.05 μm, manufactured by Mitsubishi Rayon Co., Ltd.) made of polyvinylidene fluoride (PVDF) resin was used for the membrane module.
As the membrane filter, a membrane (MF-Millipore, diameter 47 mm, nominal pore size 0.05 μm) made of cellulose mixed ester was used.
［Ｐｄ（ＩＩ）濃度］
溶液中のＰｄ（ＩＩ）濃度は、ＩＣＰ発光分光分析法により測定した。測定装置は、ＩＣＰ発光分光分析装置（島津製作所、ＩＣＥＰ−９０００）を用いた。
[Pd (II) concentration]
The concentration of Pd (II) in the solution was measured by ICP emission spectroscopy. As a measuring device, an ICP emission spectroscopic analyzer (Shimadzu Corporation, ICEP-9000) was used.
［実施例１］
図１に例示した金属回収装置１の、反応液貯留槽１０に、反応液の理論的初期濃度が以下の条件となるように、１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液（ｐＨ２．７）２４０ｍＬと、還元剤である２５０ｍＭ蟻酸ナトリウム水溶液（ｐＨ６．８）６０ｍＬとを供給し、合計３００ｍＬとした。このときの混合液のｐＨは５．８であった。
Ｐｄ（ＩＩ）濃度：１ｍＭ
蟻酸ナトリウム濃度：５０ｍＭ
反応液貯留槽１０内を４０℃に加温し、攪拌して還元反応を行った。反応開始５５分後に、当初黄色であった反応液が無色となり、黒色のＰｄ微粒子の析出が見られた。その５分後（反応開始１時間後）にＰｄ微粒子を含む溶液Ｗ１の一部を採取し、０．０５μｍのメンブレンフィルターで濾過した。ここで得られた濾液のＰｄ濃度を測定したところ、約１質量ｐｐｍであった。
次いで、１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液（ｐＨ２．７）を毎時２４０ｍＬで、２５０ｍＭ蟻酸ナトリウム水溶液（ｐＨ６．８）を毎時６０ｍＬで、反応液貯留槽１０に供給しながら、膜モジュール１４による膜濾過を行って濃縮液Ｗ２と濾過水Ｗ３とに分離し、濃縮液Ｗ２を反応液貯留槽１０に返送することで、反応液貯留槽１０内のＰｄ微粒子を濃縮した。このとき、反応液の平均液滞留時間（ＨＲＴ）が１時間となるように、濾過水Ｗ３の抜き出し速度は毎時３００ｍＬとし、反応液貯留槽１０に含まれるＰｄ微粒子を含む溶液Ｗ１の量を３００ｍＬに維持した。このとき、濾過線速度（ＬＶ）は０．２ｍ／日であった。
濾過水Ｗ３のＰｄ濃度を測定したところ、約１質量ｐｐｍであった。
このことから、１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液に含まれるパラジウムのうち、９９％以上が反応液貯留槽１０及び膜モジュール１４内に微粒子として濃縮・捕捉されていることがわかった。
反応開始１２時間後、反応液貯留槽１０からＰｄ微粒子を含む溶液Ｗ１を毎時１０ｍＬで回収部１６に回収した。このとき、濾過水Ｗ３の抜き出し速度は毎時２９０ｍＬとし、濃縮液Ｐｄ微粒子を含む溶液Ｗ１の量を３００ｍＬに維持した。回収部１６で得られた濃縮液Ｗ２を０．０５μｍのメンブレンフィルターで濾過した濾液のＰｄ濃度を測定したところ、約１質量ｐｐｍであった。また、メンブレンフィルターのろ残におけるＰｄの含量は９８％以上であった。
[Example 1]
A 1.25 mM palladium chloride (II) hydrochloric acid aqueous solution (pH 2.7) in the reaction solution storage tank 10 of the metal recovery apparatus 1 illustrated in FIG. 1 so that the theoretical initial concentration of the reaction solution satisfies the following conditions. 240 mL and 60 mL of 250 mM sodium formate aqueous solution (pH 6.8) as a reducing agent were supplied to make a total of 300 mL. The pH of the mixed solution at this time was 5.8.
Pd (II) concentration: 1 mM
Sodium formate concentration: 50 mM
The inside of the reaction liquid storage tank 10 was heated to 40 ° C. and stirred to carry out a reduction reaction. 55 minutes after the start of the reaction, the initially yellow reaction solution became colorless and precipitation of black Pd fine particles was observed. 5 minutes later (1 hour after the start of the reaction), a part of the solution W 1 containing Pd fine particles was collected and filtered through a 0.05 μm membrane filter. When the Pd concentration of the filtrate obtained here was measured, it was about 1 ppm by mass.
Then, while supplying 1.25 mM palladium chloride (II) hydrochloric acid aqueous solution (pH 2.7) at 240 mL per hour and 250 mM sodium formate aqueous solution (pH 6.8) at 60 mL per hour, the membrane module 14 The membrane was filtered to separate the concentrate W 2 and the filtrate W 3, and the concentrate W 2 was returned to the reaction solution storage tank 10 to concentrate the Pd fine particles in the reaction solution storage tank 10. At this time, the extraction rate of the filtered water W 3 is set to 300 mL / hour so that the average liquid residence time (HRT) of the reaction solution is 1 hour, and the amount of the solution W 1 containing Pd fine particles contained in the reaction solution storage tank 10. Was maintained at 300 mL. At this time, the filtration linear velocity (LV) was 0.2 m / day.
Measurement of the concentration of Pd filtered water W 3, was about 1 wt ppm.
From this, it was found that 99% or more of palladium contained in the 1.25 mM palladium chloride (II) hydrochloric acid aqueous solution was concentrated and trapped as fine particles in the reaction solution storage tank 10 and the membrane module 14.
12 hours after the start of the reaction, the solution W 1 containing Pd fine particles was recovered from the reaction liquid storage tank 10 to the recovery unit 16 at 10 mL per hour. At this time, withdrawal rate of the filtered water W 3 being the hourly 290 mL, the amount of the solution W 1 containing concentrate Pd fine particles was maintained at 300 mL. The concentrate W 2 obtained by collecting portion 16 was measured Pd concentration of the filtrate was filtered through a 0.05μm membrane filter, was about 1 wt ppm. The Pd content in the filter residue of the membrane filter was 98% or more.
［実施例２］
実施例１の、反応開始１時間後のＰｄ微粒子を含む溶液Ｗ１３００ｍＬを０．０５μｍのメンブレンフィルターで濾過し、Ｐｄ微粒子を得た。
その大部分を、図１に例示した金属回収装置１の、反応液貯留槽１０に仕込んだ後、反応液貯留槽１０に１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液（ｐＨ２．７）８０ｍＬと、還元剤である２５０ｍＭ蟻酸ナトリウム水溶液（ｐＨ６．８）２０ｍＬとを供給し、合計１００ｍＬとした後、反応液貯留槽１０内を４０℃に加温し、攪拌して、Ｐｄ微粒子存在下にて還元反応を行った。
反応開始１５分後に、当初黄色であった反応液が無色となり、黒色のＰｄ微粒子の析出が見られた。その５分後（反応開始２０分後）にＰｄ微粒子を含む溶液Ｗ１の一部を採取し、０．０５μｍのメンブレンフィルターで濾過した濾液のＰｄ濃度を測定したところ、約１質量ｐｐｍであった。
次いで、１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液（ｐＨ２．７）を毎時２４０ｍＬで、２５０ｍＭ蟻酸ナトリウム水溶液（ｐＨ６．８）を毎時６０ｍＬで、反応液貯留槽１０に供給しながら、膜モジュール１４による膜濾過を行って濃縮液Ｗ２と濾過水Ｗ３とに分離し、濃縮液Ｗ２を反応液貯留槽１０に返送することで、反応液貯留槽１０内のＰｄ微粒子を濃縮した。このとき、反応液の平均液滞留時間（ＨＲＴ）が２０分間となるように、濾過水Ｗ３の抜き出し速度は毎時３００ｍＬとし、反応液貯留槽１０に含まれるＰｄ微粒子を含む溶液Ｗ１の量を１００ｍＬに維持した。このとき、濾過線速度（ＬＶ）は０．２ｍ／日であった。
濾過水Ｗ３のＰｄ濃度を測定したところ、約１質量ｐｐｍであった。
このことから、１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液に含まれるパラジウムのうち、９９％以上が反応液貯留槽１０及び膜モジュール１４内に微粒子として濃縮・捕捉されていることがわかった。
反応開始１２時間後、反応液貯留槽１０から濃縮液Ｗ１を毎時１０ｍＬで連続的に回収部１６に回収した。このとき、濾過水Ｗ３の抜き出し速度は毎時２９０ｍＬとし、反応液貯留槽１０に含まれるＰｄ微粒子を含む溶液Ｗ１の量を１００ｍＬに維持した。回収部１６で得られた濃縮液Ｗ１を０．０５μｍのメンブレンフィルターで濾過した濾液のＰｄ濃度を測定したところ、約１質量ｐｐｍであった。また、メンブレンフィルターのろ残におけるＰｄの含量は９８％以上であった。
[Example 2]
300 mL of the solution W 1 containing Pd fine particles 1 hour after the start of the reaction in Example 1 was filtered through a 0.05 μm membrane filter to obtain Pd fine particles.
Most of the solution was charged into the reaction liquid storage tank 10 of the metal recovery apparatus 1 illustrated in FIG. 1, and then the reaction liquid storage tank 10 was charged with 80 mL of 1.25 mM palladium chloride (II) hydrochloric acid aqueous solution (pH 2.7). Then, 20 mL of a 250 mM sodium formate aqueous solution (pH 6.8) as a reducing agent was supplied to make a total of 100 mL, and then the reaction solution storage tank 10 was heated to 40 ° C. and stirred, in the presence of Pd fine particles. A reduction reaction was performed.
After 15 minutes from the start of the reaction, the reaction solution which was initially yellow became colorless and precipitation of black Pd fine particles was observed. Five minutes later (20 minutes after the start of the reaction), a part of the solution W 1 containing Pd fine particles was collected, and when the Pd concentration of the filtrate filtered through a 0.05 μm membrane filter was measured, it was about 1 ppm by mass. It was.
Then, while supplying 1.25 mM palladium chloride (II) hydrochloric acid aqueous solution (pH 2.7) at 240 mL per hour and 250 mM sodium formate aqueous solution (pH 6.8) at 60 mL per hour, the membrane module 14 The membrane was filtered to separate the concentrate W 2 and the filtrate W 3, and the concentrate W 2 was returned to the reaction solution storage tank 10 to concentrate the Pd fine particles in the reaction solution storage tank 10. At this time, the extraction rate of the filtered water W 3 is set to 300 mL / hour so that the average liquid residence time (HRT) of the reaction solution is 20 minutes, and the amount of the solution W 1 containing Pd fine particles contained in the reaction solution storage tank 10. Was maintained at 100 mL. At this time, the filtration linear velocity (LV) was 0.2 m / day.
Measurement of the concentration of Pd filtered water W 3, was about 1 wt ppm.
From this, it was found that 99% or more of palladium contained in the 1.25 mM palladium chloride (II) hydrochloric acid aqueous solution was concentrated and trapped as fine particles in the reaction solution storage tank 10 and the membrane module 14.
Twelve hours after the start of the reaction, the concentrated solution W 1 was continuously collected from the reaction solution storage tank 10 into the collection unit 16 at 10 mL / hour. At this time, the extraction speed of the filtered water W 3 was 290 mL per hour, and the amount of the solution W 1 containing Pd fine particles contained in the reaction liquid storage tank 10 was maintained at 100 mL. The concentrate W 1 obtained in recovery unit 16 was measured Pd concentration of the filtrate was filtered through a 0.05μm membrane filter, was about 1 wt ppm. The Pd content in the filter residue of the membrane filter was 98% or more.
［実施例３］
図１に例示した金属回収装置１の、反応液貯留槽１０に、１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液（ｐＨ２．７）８０ｍＬと、還元剤である２５０ｍＭ蟻酸ナトリウム水溶液（ｐＨ６．８）２０ｍＬとを供給し、合計１００ｍＬとした後、２００ｍｍｏｌ／ｋｇ硫酸鉄（ＩＩ）の５０ｍｍｏｌ／ｋｇ硫酸水溶液１ｍＬを加え、反応液貯留槽１０内を４０℃に加温し、攪拌して、Ｐｄ微粒子存在下にて還元反応を行った。
反応開始５分後に、当初黄色であった反応液が無色となり、黒色のＰｄ微粒子の析出が見られた。その５分後（反応開始１０分後）にＰｄ微粒子を含む溶液Ｗ１の一部を採取し、０．０５μｍのメンブレンフィルターで濾過した濾液のＰｄ濃度を測定したところ、約１質量ｐｐｍであった。
次いで、１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液（ｐＨ２．７）を毎時２４０ｍＬで、２５０ｍＭ蟻酸ナトリウム水溶液（ｐＨ６．８）を毎時６０ｍＬで、反応液貯留槽１０に供給しながら、膜モジュール１４による膜濾過を行って濃縮液Ｗ２と濾過水Ｗ３とに分離し、濃縮液Ｗ２を反応液貯留槽１０に返送することで、反応液貯留槽１０内のＰｄ微粒子を濃縮した。このとき、反応液の平均液滞留時間（ＨＲＴ）が２０分間となるように、濾過水Ｗ３の抜き出し速度は毎時３００ｍＬとし、反応液貯留槽１０に含まれるＰｄ微粒子を含む溶液Ｗ１の量を１００ｍＬに維持した。このとき、濾過線速度（ＬＶ）は０．２ｍ／日であった。
濾過水Ｗ３のＰｄ濃度を測定したところ、約１質量ｐｐｍであった。
このことから、１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液に含まれるパラジウムのうち、９９％以上が反応液貯留槽１０及び膜モジュール１４内に微粒子として濃縮・捕捉されていることがわかった。
反応開始１２時間後、反応液貯留槽１０から濃縮液Ｗ１を毎時１０ｍＬで連続的に回収部１６に回収した。このとき、濾過水Ｗ３の抜き出し速度は毎時２９０ｍＬとし、反応液貯留槽１０に含まれるＰｄ微粒子を含む溶液Ｗ１の量を１００ｍＬに維持した。回収部１６で得られた濃縮液Ｗ１を０．０５μｍのメンブレンフィルターで濾過した濾液のＰｄ濃度を測定したところ、約１質量ｐｐｍであった。また、メンブレンフィルターのろ残におけるＰｄの含量は９８％以上であった。
[Example 3]
In the reaction liquid storage tank 10 of the metal recovery apparatus 1 illustrated in FIG. 1, 80 mL of 1.25 mM palladium (II) chloride acidic aqueous solution (pH 2.7) and 250 mM sodium formate aqueous solution (pH 6.8) as a reducing agent. 20 mL is supplied to make a total of 100 mL, 1 mL of 50 mmol / kg sulfuric acid aqueous solution of 200 mmol / kg iron (II) sulfate is added, the inside of the reaction solution storage tank 10 is heated to 40 ° C., stirred, and Pd fine particles The reduction reaction was performed in the presence.
Five minutes after the start of the reaction, the initially yellow reaction solution became colorless and precipitation of black Pd fine particles was observed. Five minutes later (10 minutes after the start of the reaction), a part of the solution W 1 containing Pd fine particles was collected, and the Pd concentration of the filtrate filtered through a 0.05 μm membrane filter was measured. It was.
Then, while supplying 1.25 mM palladium chloride (II) hydrochloric acid aqueous solution (pH 2.7) at 240 mL per hour and 250 mM sodium formate aqueous solution (pH 6.8) at 60 mL per hour, the membrane module 14 The membrane was filtered to separate the concentrate W 2 and the filtrate W 3, and the concentrate W 2 was returned to the reaction solution storage tank 10 to concentrate the Pd fine particles in the reaction solution storage tank 10. At this time, the extraction rate of the filtered water W 3 is set to 300 mL / hour so that the average liquid residence time (HRT) of the reaction solution is 20 minutes, and the amount of the solution W 1 containing Pd fine particles contained in the reaction solution storage tank 10. Was maintained at 100 mL. At this time, the filtration linear velocity (LV) was 0.2 m / day.
Measurement of the concentration of Pd filtered water W 3, was about 1 wt ppm.
From this, it was found that 99% or more of palladium contained in the 1.25 mM palladium chloride (II) hydrochloric acid aqueous solution was concentrated and trapped as fine particles in the reaction solution storage tank 10 and the membrane module 14.
Twelve hours after the start of the reaction, the concentrated solution W 1 was continuously collected from the reaction solution storage tank 10 into the collection unit 16 at 10 mL / hour. At this time, the extraction speed of the filtered water W 3 was 290 mL per hour, and the amount of the solution W 1 containing Pd fine particles contained in the reaction liquid storage tank 10 was maintained at 100 mL. The concentrate W 1 obtained in recovery unit 16 was measured Pd concentration of the filtrate was filtered through a 0.05μm membrane filter, was about 1 wt ppm. The Pd content in the filter residue of the membrane filter was 98% or more.
［比較例１］
図１に例示した金属回収装置１の、反応液貯留槽１０に１．２５ｍＭ塩化パラジウム（ＩＩ）塩酸酸性水溶液（ｐＨ２．７）２４０ｍＬと、水６０ｍＬを供給し、合計３００ｍＬとした後、還元剤として、水素吸蔵合金（事前に３０℃、１．８ＭＰａにて３時間水素を吸蔵させたランタン−ニッケル合金粉末）２．２ｇを加え、反応液貯留槽１０内を４０℃に加温し、１時間攪拌して還元反応を行った。１時間後に水素吸蔵合金粉末及びＰｄ微粒子を含む溶液Ｗ１の一部を採取し、０．０５μｍのメンブレンフィルターで濾過した濾液のＰｄ濃度を測定したところ、約１質量ｐｐｍであったが、濃縮され得られた固形分の９８％が水素吸蔵合金由来であった。
[Comparative Example 1]
After supplying 240 mL of 1.25 mM palladium (II) hydrochloric acid acidic aqueous solution (pH 2.7) and 60 mL of water to the reaction solution storage tank 10 of the metal recovery apparatus 1 illustrated in FIG. As described above, 2.2 g of a hydrogen storage alloy (lanthanum-nickel alloy powder previously stored with hydrogen at 30 ° C. and 1.8 MPa for 3 hours) was added, and the inside of the reaction liquid storage tank 10 was heated to 40 ° C. The reduction reaction was carried out with stirring for a period of time. One hour later, a part of the solution W 1 containing the hydrogen storage alloy powder and Pd fine particles was collected, and the Pd concentration of the filtrate filtered through a 0.05 μm membrane filter was measured. 98% of the solid content thus obtained was derived from a hydrogen storage alloy.
前記実施例及び比較例の概要を表１に示す。 A summary of the examples and comparative examples is shown in Table 1.
表１より、水溶性還元剤を用いた実施例１〜３は、パラジウム微粒子を主成分とする固形分が得られるという効果があった。
特に、２価鉄イオンを作用させた実施例３は、パラジウム微粒子の析出が加速し、反応効率が良好であった。
一方、水素吸蔵合金粉末を用いた比較例１は、実施例１〜３と比べて、得られる固形分の９８％が水素吸蔵合金由来のものであった。
よって、本発明によれば、効率良くかつ簡便に、純度の高い金属を濃縮・回収することができる。
From Table 1, Examples 1-3 using a water-soluble reducing agent had the effect that the solid content which has a palladium fine particle as a main component was obtained.
In particular, in Example 3 in which divalent iron ions were allowed to act, the precipitation of palladium fine particles was accelerated and the reaction efficiency was good.
On the other hand, in Comparative Example 1 using the hydrogen storage alloy powder, 98% of the solid content obtained was derived from the hydrogen storage alloy as compared with Examples 1 to 3.
Therefore, according to the present invention, a highly pure metal can be concentrated and recovered efficiently and simply.
１ 金属回収装置
１０ 反応液貯留槽
１４ 膜モジュール
１６ 回収部
５８ 返送部
DESCRIPTION OF SYMBOLS 1 Metal recovery apparatus 10 Reaction liquid storage tank 14 Membrane module 16 Recovery part 58 Return part
Claims (6)
前記工程（１）にて、前記金属イオンを還元させてなる金属を予め含有させる、金属回収方法。
（１）金属イオン含有溶液に水溶性還元剤を作用させて、金属イオンを還元し、金属微粒子とする、還元工程；
（２）前記工程（１）で得られる金属微粒子を含む溶液を、濾過膜により濃縮して、濃縮液を得る、濃縮工程； A method for recovering a metal from a solution containing metal ions, comprising the following steps (1) and (2) :
A metal recovery method, wherein a metal obtained by reducing the metal ion is previously contained in the step (1) .
(1) A reduction step in which a water-soluble reducing agent is allowed to act on a metal ion-containing solution to reduce metal ions to form metal fine particles;
(2) A concentration step of concentrating the solution containing the metal fine particles obtained in the step (1) with a filtration membrane to obtain a concentrated solution;
（３）前記工程（２）で得られる濃縮液を、前記工程（１）に戻す、返送工程； Furthermore, the metal collection | recovery method of Claim 1 including the following process (3).
(3) A returning step of returning the concentrate obtained in the step (2) to the step (1);
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| AU542195B2 (en) * | 1980-09-05 | 1985-02-14 | Inco Ltd. | The extraction of precious metals from concentrates |
| JP2003147444A (en) * | 2001-11-09 | 2003-05-21 | Nippon Parkerizing Co Ltd | Method for recovering valuable metal from metal cyanide-containing solution |
| JP2008169151A (en) * | 2007-01-12 | 2008-07-24 | Ainobekkusu Kk | Method for producing aqueous solution containing metal colloid by using lecithin or saponin |
| JP2009019256A (en) * | 2007-07-13 | 2009-01-29 | Denso Corp | Method for producing metal nanoparticle fluid dispersion |
| JP5332624B2 (en) * | 2008-01-22 | 2013-11-06 | 三菱マテリアル株式会社 | Metal nanoparticle dispersion and method for producing the same |
| JP2011048876A (en) * | 2009-08-27 | 2011-03-10 | Renesas Electronics Corp | Semiconductor memory device and method for controlling the same |
| CN102676822B (en) * | 2011-03-11 | 2014-01-01 | 深圳市格林美高新技术股份有限公司 | Burning-free non-cyaniding method for treating waste printed circuit board |
| WO2013002195A1 (en) * | 2011-06-30 | 2013-01-03 | 富士フイルム株式会社 | Conductive film, method for producing same, and touch panel |
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