JP6815242B2 - Treatment method of liquid to be treated and silver recovery method - Google Patents
Treatment method of liquid to be treated and silver recovery method Download PDFInfo
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- JP6815242B2 JP6815242B2 JP2017058489A JP2017058489A JP6815242B2 JP 6815242 B2 JP6815242 B2 JP 6815242B2 JP 2017058489 A JP2017058489 A JP 2017058489A JP 2017058489 A JP2017058489 A JP 2017058489A JP 6815242 B2 JP6815242 B2 JP 6815242B2
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- 239000007788 liquid Substances 0.000 title claims description 149
- 229910052709 silver Inorganic materials 0.000 title claims description 95
- 239000004332 silver Substances 0.000 title claims description 95
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 title claims description 92
- 238000000034 method Methods 0.000 title claims description 57
- 238000011084 recovery Methods 0.000 title claims description 15
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 116
- 239000002738 chelating agent Substances 0.000 claims description 44
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 claims description 40
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims description 39
- 239000002699 waste material Substances 0.000 claims description 37
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 36
- 238000010438 heat treatment Methods 0.000 claims description 35
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 35
- 239000000243 solution Substances 0.000 claims description 33
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims description 27
- 238000000926 separation method Methods 0.000 claims description 24
- 238000001704 evaporation Methods 0.000 claims description 22
- 230000008020 evaporation Effects 0.000 claims description 20
- QPCDCPDFJACHGM-UHFFFAOYSA-N N,N-bis{2-[bis(carboxymethyl)amino]ethyl}glycine Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC(O)=O QPCDCPDFJACHGM-UHFFFAOYSA-N 0.000 claims description 19
- 238000006386 neutralization reaction Methods 0.000 claims description 17
- 238000010790 dilution Methods 0.000 claims description 13
- 239000012895 dilution Substances 0.000 claims description 13
- 239000000463 material Substances 0.000 claims description 13
- 229910052984 zinc sulfide Inorganic materials 0.000 claims description 13
- 239000005083 Zinc sulfide Substances 0.000 claims description 12
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 claims description 12
- 239000000126 substance Substances 0.000 claims description 11
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical compound [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 239000007787 solid Substances 0.000 claims description 8
- AGMNQPKGRCRYQP-UHFFFAOYSA-N 2-[2-[2-[bis(carboxymethyl)amino]ethylamino]ethyl-(carboxymethyl)amino]acetic acid Chemical compound OC(=O)CN(CC(O)=O)CCNCCN(CC(O)=O)CC(O)=O AGMNQPKGRCRYQP-UHFFFAOYSA-N 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 5
- 239000000919 ceramic Substances 0.000 claims description 5
- 238000007865 diluting Methods 0.000 claims description 5
- 239000000758 substrate Substances 0.000 claims description 5
- 239000003085 diluting agent Substances 0.000 claims description 4
- DPLVEEXVKBWGHE-UHFFFAOYSA-N potassium sulfide Chemical compound [S-2].[K+].[K+] DPLVEEXVKBWGHE-UHFFFAOYSA-N 0.000 claims description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 18
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 12
- 229910021529 ammonia Inorganic materials 0.000 description 9
- 239000000706 filtrate Substances 0.000 description 8
- 230000003100 immobilizing effect Effects 0.000 description 8
- 229910052946 acanthite Inorganic materials 0.000 description 7
- 238000000354 decomposition reaction Methods 0.000 description 7
- XUARKZBEFFVFRG-UHFFFAOYSA-N silver sulfide Chemical compound [S-2].[Ag+].[Ag+] XUARKZBEFFVFRG-UHFFFAOYSA-N 0.000 description 7
- 229940056910 silver sulfide Drugs 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 238000001914 filtration Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 229910001431 copper ion Inorganic materials 0.000 description 4
- 239000012153 distilled water Substances 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- -1 silver ions Chemical class 0.000 description 4
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 230000009918 complex formation Effects 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 238000012795 verification Methods 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 208000035404 Autolysis Diseases 0.000 description 2
- 206010057248 Cell death Diseases 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- YRKCREAYFQTBPV-UHFFFAOYSA-N acetylacetone Chemical compound CC(=O)CC(C)=O YRKCREAYFQTBPV-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 2
- 235000011130 ammonium sulphate Nutrition 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 230000003472 neutralizing effect Effects 0.000 description 2
- 238000006864 oxidative decomposition reaction Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000028043 self proteolysis Effects 0.000 description 2
- 229910001961 silver nitrate Inorganic materials 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910021607 Silver chloride Inorganic materials 0.000 description 1
- FOIXSVOLVBLSDH-UHFFFAOYSA-N Silver ion Chemical compound [Ag+] FOIXSVOLVBLSDH-UHFFFAOYSA-N 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 229920006318 anionic polymer Polymers 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000013522 chelant Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- MPTQRFCYZCXJFQ-UHFFFAOYSA-L copper(II) chloride dihydrate Chemical compound O.O.[Cl-].[Cl-].[Cu+2] MPTQRFCYZCXJFQ-UHFFFAOYSA-L 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000003113 dilution method Methods 0.000 description 1
- KCIDZIIHRGYJAE-YGFYJFDDSA-L dipotassium;[(2r,3r,4s,5r,6r)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl] phosphate Chemical compound [K+].[K+].OC[C@H]1O[C@H](OP([O-])([O-])=O)[C@H](O)[C@@H](O)[C@H]1O KCIDZIIHRGYJAE-YGFYJFDDSA-L 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910052976 metal sulfide Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000011085 pressure filtration Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 1
- 235000011121 sodium hydroxide Nutrition 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 150000004763 sulfides Chemical class 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000005987 sulfurization reaction Methods 0.000 description 1
- 230000000007 visual effect Effects 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
- Heat Treatment Of Water, Waste Water Or Sewage (AREA)
- Removal Of Specific Substances (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
- Manufacture And Refinement Of Metals (AREA)
Description
本発明は、被処理液の処理方法および銀の回収方法に関する。 The present invention relates to a method for treating a liquid to be treated and a method for recovering silver.
電子・電気回路基板を作製する際にはエッチングに伴い過酸化水素や諸々の金属元素を含有する廃液が発生する。このような廃液を処理する際に、過酸化水素が突沸するという問題が知られている。この問題に対処すべく、例えば特許文献１や特許文献２では、活性炭や白金族元素を触媒として用いた過酸化水素分解法が提案されている。この他、特許文献３では、ｐＨ調整と温度制御を組み合わせた過酸化水素の分解方法が提案されている。 When manufacturing electronic / electric circuit boards, waste liquid containing hydrogen peroxide and various metal elements is generated during etching. It is known that hydrogen peroxide suddenly boils when treating such a waste liquid. In order to deal with this problem, for example, Patent Document 1 and Patent Document 2 propose a hydrogen peroxide decomposition method using activated carbon or a platinum group element as a catalyst. In addition, Patent Document 3 proposes a method for decomposing hydrogen peroxide that combines pH adjustment and temperature control.
電子・電気回路基板のうち例えばパワーモジュール等に用いられる金属−セラミック接合基板の製造工程では、剥離液や洗浄液を使用する結果、数十ｇ／Ｌの過酸化水素、アンモニア、溶液の安定化のために使用されるキレート剤、そして銅や銀など金属元素を含むアルカリ性の廃液が発生する場合がある。
上記のアルカリ性の廃液に関して言うと、過酸化水素は、アルカリ条件下では不安定であり、自己分解が促進される。そのため、廃液を加温することにより過酸化水素を自己分解させて廃液から除去することが可能である。
In the manufacturing process of metal-ceramic bonded substrates used for, for example, power modules among electronic / electric circuit boards, as a result of using a stripping solution or cleaning solution, tens of g / L of hydrogen peroxide, ammonia, and solution are stabilized. Chelating agents used for this purpose, and alkaline effluents containing metallic elements such as copper and silver may be generated.
With respect to the alkaline waste liquid described above, hydrogen peroxide is unstable under alkaline conditions and autolysis is promoted. Therefore, it is possible to autolyze hydrogen peroxide and remove it from the waste liquid by heating the waste liquid.
有価物として例えば銀を回収する手法としては、例えば、上記の廃液に塩酸を加え、廃液中の銀を塩化銀の沈殿として固定するという手法が挙げられる。なお、本明細書で言う“固定化”とは“銀含有物として沈殿させること”を指す。また、“銀”のように金属元素を表記する際には、金属銀や銀イオンを含めたものとするが、わかりやすくすべく銀イオンと称することもある。銀の固定化後、廃液を加温して過酸化水素を自己分解させて除去すればよいように見える。
しかしながら該手法では、未分解の過酸化水素を含むアルカリ性の廃液に塩酸を添加することになり、中和熱による液温度上昇そして急激な過酸化水素の分解に伴い、激しい突沸が起こるおそれがある。また、塩酸を使用するとなると、廃液処理に係る装置や設備の材質としては、塩酸に対して耐食性を有するものを使用しなければならずコストが嵩む。
As a method of recovering silver as a valuable resource, for example, a method of adding hydrochloric acid to the above-mentioned waste liquid and fixing silver in the waste liquid as a precipitate of silver chloride can be mentioned. In addition, "immobilization" as used herein means "precipitation as a silver-containing substance". In addition, when describing a metal element such as "silver", it is assumed that metallic silver and silver ions are included, but it may also be referred to as silver ions for the sake of clarity. After fixing the silver, it seems that the waste liquid should be heated to autolyze and remove the hydrogen peroxide.
However, in this method, hydrochloric acid is added to the alkaline waste liquid containing undecomposed hydrogen peroxide, and the liquid temperature rises due to the heat of neutralization and the rapid decomposition of hydrogen peroxide may cause severe bumping. .. Further, when hydrochloric acid is used, it is necessary to use a material having corrosion resistance to hydrochloric acid as the material of the device or equipment related to the waste liquid treatment, which increases the cost.
なお、上記の廃液に塩酸を加える代わりにピペラジン系キレート剤により不溶銀錯体を形成するという手法も挙げられるが、この場合、廃液からの銀の回収率という観点から見ても改善すべき課題がある。 There is also a method of forming an insoluble silver complex with a piperazine-based chelating agent instead of adding hydrochloric acid to the above-mentioned waste liquid, but in this case, there is a problem to be improved from the viewpoint of the recovery rate of silver from the waste liquid. is there.
本発明の課題は、被処理液の処理コストを抑える手法を提供することにある。また別の課題は、それに加え、銀の回収率を向上させる手法を提供することにある。 An object of the present invention is to provide a method for suppressing the treatment cost of the liquid to be treated. Another challenge is to provide a method for improving the silver recovery rate.
上記の課題を解決すべく、本発明者は鋭意研究を行った。過酸化水素が分解して発熱する前に、まずは、過酸化水素の影響が及ばないようにすべく硫化物により銀をほとんど固定化し、その後、廃液（広義には被処理液）を加温することにより過酸化水素を自己分解させて廃液から除去する、という手法を想到した。
更に、過酸化水素の自己分解前だと銀の固定化という効果を十分に発揮できなかったピペラジン系キレート剤を、上記手法により過酸化水素を除去した後に使用して残りの銀を回収する、という手法を想到した。
この知見に基づきなされた本発明の態様は、以下の通りである。
In order to solve the above problems, the present inventor has conducted diligent research. Before hydrogen peroxide decomposes and generates heat, first, silver is mostly fixed with sulfide so that it is not affected by hydrogen peroxide, and then the waste liquid (in a broad sense, the liquid to be treated) is heated. As a result, I came up with a method of self-decomposing hydrogen peroxide and removing it from the waste liquid.
Furthermore, a piperazine-based chelating agent, which could not sufficiently exert the effect of immobilizing silver before the autolysis of hydrogen peroxide, is used after removing hydrogen peroxide by the above method to recover the remaining silver. I came up with the method.
Aspects of the present invention made based on this finding are as follows.
本発明の第１の態様は、
銀と、過酸化水素と、エチレンジアミン四酢酸（ＥＤＴＡ）およびジエチレントリアミン五酢酸（ＤＴＰＡ）の少なくともいずれかであるキレート剤と、を含有するアルカリ性の被処理液の処理方法であって、
被処理液に対して硫化物を添加する硫化物添加工程と、
硫化物が添加された被処理液を加温して過酸化水素を除去する加温工程と、
過酸化水素が除去された被処理液に対してピペラジン系キレート剤を添加するキレート剤添加工程と、
を有する、被処理液の処理方法である。
The first aspect of the present invention is
A method for treating an alkaline object to be treated, which comprises silver, hydrogen peroxide, and a chelating agent which is at least one of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminetetraacetic acid (DTPA).
A sulfide addition step of adding sulfide to the liquid to be treated,
A heating process that heats the liquid to be treated to which sulfide is added to remove hydrogen peroxide, and
A chelating agent addition step of adding a piperazine-based chelating agent to the liquid to be treated from which hydrogen peroxide has been removed, and
It is a method for treating a liquid to be treated.
本発明の第２の態様は、第１の態様に記載の発明において、
前記キレート剤添加工程後、被処理液を固液分離することにより、固体である銀含有物を回収する固液分離工程を更に有する。
A second aspect of the present invention is the invention described in the first aspect.
After the chelating agent addition step, the solid-liquid separation step of recovering the solid silver-containing material is further provided by solid-liquid separation of the liquid to be treated.
本発明の第３の態様は、第２の態様に記載の発明において、
前記固液分離工程で生じた液体に酸を加えて中和する中和工程を更に有する。
A third aspect of the present invention is the invention described in the second aspect.
It further has a neutralization step of adding an acid to the liquid generated in the solid-liquid separation step to neutralize the liquid.
本発明の第４の態様は、第３の態様に記載の発明において、
前記中和工程で中和された液体を蒸発濃縮させる蒸発濃縮工程を更に有する。
A fourth aspect of the present invention is the invention described in the third aspect.
It further has an evaporation concentration step of evaporating and concentrating the liquid neutralized in the neutralization step.
本発明の第５の態様は、第４の態様に記載の発明において、
前記蒸発濃縮工程で蒸発濃縮により生じた凝縮水に含有されるホルムアルデヒドを除去する凝縮水処理工程を更に有する。
A fifth aspect of the present invention is the invention described in the fourth aspect.
It further has a condensed water treatment step of removing formaldehyde contained in the condensed water generated by the evaporation concentration in the evaporation concentration step.
本発明の第６の態様は、第１〜第５のいずれかの態様に記載の発明において、
前記加温工程の前に、被処理液における過酸化水素の濃度が２０ｇ／Ｌ以下となるまで被処理液を希釈する希釈工程を更に有する。
A sixth aspect of the present invention is the invention described in any one of the first to fifth aspects.
Prior to the heating step, there is further a dilution step of diluting the liquid to be treated until the concentration of hydrogen peroxide in the liquid to be treated becomes 20 g / L or less.
本発明の第７の態様は、第６の態様に記載の発明において、
前記キレート剤添加工程後、被処理液を固液分離することにより、固体である銀含有物を回収する固液分離工程と、を有し、
前記希釈工程における希釈液として、前記固液分離工程で生じた液体の一部を用いる。
A seventh aspect of the present invention is the invention described in the sixth aspect.
After the chelating agent addition step, a solid-liquid separation step of recovering a solid silver-containing substance by solid-liquid separation of the liquid to be treated is provided.
As the diluent in the dilution step, a part of the liquid generated in the solid-liquid separation step is used.
本発明の第８の態様は、第１〜第７のいずれかの態様に記載の発明において、
前記被処理液は金属−セラミック接合基板の製造の際の廃液である。
An eighth aspect of the present invention is the invention described in any one of the first to seventh aspects.
The liquid to be treated is a waste liquid in the production of a metal-ceramic bonded substrate.
本発明の第９の態様は、第１〜第８のいずれかの態様に記載の発明において、
前記硫化物は硫化カリウム、硫化亜鉛および硫化銅の少なくともいずれかである。
A ninth aspect of the present invention is the invention according to any one of the first to eighth aspects.
The sulfide is at least one of potassium sulfide, zinc sulfide and copper sulfide.
本発明の第１０の態様は、
銀と、過酸化水素と、エチレンジアミン四酢酸（ＥＤＴＡ）およびジエチレントリアミン五酢酸（ＤＴＰＡ）の少なくともいずれかであるキレート剤と、を含有するアルカリ性の被処理液からの銀の回収方法であって、
被処理液に対して硫化物を添加する硫化物添加工程と、
硫化物が添加された被処理液を加温して過酸化水素を除去する加温工程と、
過酸化水素が除去された被処理液に対してピペラジン系キレート剤を添加するキレート剤添加工程と、
キレート剤添加工程後、被処理液を固液分離することにより、固体である銀含有物を回収する固液分離工程と、
銀含有物から銀を回収する銀回収工程と、
を有する、銀の回収方法である。
A tenth aspect of the present invention is
A method for recovering silver from an alkaline treatment solution containing silver, hydrogen peroxide, and a chelating agent that is at least one of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminetetraacetic acid (DTPA).
A sulfide addition step of adding sulfide to the liquid to be treated,
A heating process that heats the liquid to be treated to which sulfide is added to remove hydrogen peroxide, and
A chelating agent addition step of adding a piperazine-based chelating agent to the liquid to be treated from which hydrogen peroxide has been removed, and
After the chelating agent addition step, the solid-liquid separation step of recovering the solid silver-containing material by solid-liquid separation of the liquid to be treated,
A silver recovery process that recovers silver from silver-containing materials,
It is a silver recovery method having.
本発明によれば、被処理液の処理コストを抑えることを可能とする。また、それに加え、銀の回収率を向上させることを可能とする。 According to the present invention, it is possible to reduce the treatment cost of the liquid to be treated. In addition, it makes it possible to improve the silver recovery rate.
本実施形態においては以下の順番で説明を行い、フローチャートである図１を用いて説明する。
１．硫化物添加工程
２．希釈工程
３．加温工程
４．キレート剤添加工程
５．固液分離工程（銀の回収方法）
６．中和工程
７．蒸発濃縮工程
８．凝縮水処理工程
なお、本明細書における「〜」は所定の数値以上かつ所定の数値以下を指す。
また、本実施形態で用いる被処理液としては金属−セラミック接合基板の製造の際の廃液を具体例として挙げるが、その組成としては、銀と、過酸化水素と、エチレンジアミン四酢酸（ＥＤＴＡ）およびジエチレントリアミン五酢酸（ＤＴＰＡ）の少なくともいずれかであるキレート剤と、を含有するアルカリ性の溶液であれば特に限定は無いし、これらのものを含有するのならば廃液でなくとも構わない。
In this embodiment, the description will be given in the following order, and the description will be given with reference to FIG. 1, which is a flowchart.
1. 1. Sulfide addition process 2. Dilution step 3. Heating process 4. Chelating agent addition process 5. Solid-liquid separation process (silver recovery method)
6. Neutralization process 7. Evaporation concentration process 8. Condensed water treatment step In this specification, "~" refers to a predetermined value or more and a predetermined value or less.
Further, as the liquid to be treated in this embodiment, waste liquid in the production of a metal-ceramic bonded substrate is given as a specific example, and the composition thereof includes silver, hydrogen peroxide, ethylenediaminetetraacetic acid (EDTA) and There is no particular limitation as long as it is an alkaline solution containing at least one of diethylenetriaminepentacetic acid (DTPA) and a chelating agent, and if these are contained, it does not have to be a waste liquid.
（１．硫化物添加工程）
硫化物添加工程においては廃液に対して硫化物を添加する。硫化物の添加により、廃液中の銀を硫化銀とすることによって固定化する。なお、硫化物による銀の沈殿の溶解度積は難溶性の沈殿（ＫＳＰ（Ａｇ２Ｓ）＝６．３ｘ１０−５０）であり、本実施形態における後述の加温工程を経ても再溶解はほとんど生じない。
(1. Sulfide addition step)
In the sulfide addition step, sulfide is added to the waste liquid. By adding sulfide, silver in the waste liquid is fixed by converting it to silver sulfide. Incidentally, the solubility product of the precipitation of the silver by the sulfide is a precipitation of sparingly soluble (K SP (Ag2S) = 6.3x10 -50), redissolved hardly occurs even after the heating step described later in this embodiment ..
上記硫化物としては任意の公知のものを使用すればよいが、銀よりも溶解度積の大きな化合物を用いるのが好ましく、例えば硫化亜鉛や硫化銅などが挙げられる。他には硫化カリウムも挙げられる。また、具体的な化合物名としては、例えばＦｅＳ、Ｆｅ２Ｓ３、Ｋ２Ｓ、Ｎａ２Ｓ、ＭｎＳ、ＰｂＳなど金属硫化物およびそれらを含む化合物が挙げられる。また、添加量については特に限定は無いが廃液中の銀の等量以上が好ましい。 Any known sulfide may be used, but it is preferable to use a compound having a solubility product larger than that of silver, and examples thereof include zinc sulfide and copper sulfide. Another example is potassium sulfide. Specific compound names include metal sulfides such as FeS, Fe 2 S 3 , K 2 S, Na 2 S, MnS, and PbS, and compounds containing them. The amount of silver added is not particularly limited, but is preferably equal to or more than the equivalent amount of silver in the waste liquid.
硫化物の中でも硫化亜鉛や硫化銅が好ましい。その理由は以下の通りである。
本実施形態の被処理液である廃液には、銀と、過酸化水素と、エチレンジアミン四酢酸（ＥＤＴＡ）およびジエチレントリアミン五酢酸（ＤＴＰＡ）の少なくともいずれかと、が含有されている。先に述べたように、ＥＤＴＡやＤＴＰＡを廃液に含有させているのは溶液を安定化させるため（銀を活性の高い状態にしないようにＥＤＴＡやＤＴＰＡを銀イオンへと配位させるため）である。この状態で硫化亜鉛や硫化銅をアルカリ性の廃液に添加すると、以下の反応式に示すように、硫化亜鉛や硫化銅は亜鉛イオンや銅イオンおよび硫化物イオンへとイオン化する。
ＺｎＳ→Ｚｎ２＋＋Ｓ２−
ＣｕＳ→Ｃｕ２＋＋Ｓ２−
この硫化物イオン（Ｓ２−）が廃液中の銀イオンと結合して硫化銀を生成することにより銀を固定化することになる。その一方で、亜鉛イオンや銅イオンは、ＥＤＴＡやＤＴＰＡに対し、速やかに安定なキレート錯体となる。例えば、ＥＤＴＡと銀との錯体の錯生成定数７．３２であるのに対し、ＥＤＴＡと亜鉛との錯体の錯生成定数１６．５０であり、ＥＤＴＡと亜鉛との錯体の方が安定である（出典：「ポイント分析化学演習」２６４頁、著：河嶌拓治他、出版：廣川書店）。なお、ＥＤＴＡと類似する炭素骨格を有するＤＴＰＡも亜鉛に対しては同程度の錯生成定数を有するものと考えられるし、銅イオンもＥＤＴＡやＤＴＰＡと錯体を形成し易くかつ該錯体は安定である。
つまり、上記の反応式における右辺の亜鉛イオンや銅イオンが、ＥＤＴＡやＤＴＰＡとの錯化によって減少していく。そうなると上記の反応式における反応は更に右辺へと偏ることになり、硫化亜鉛や硫化銅を十分にイオン化でき、ひいては十分に銀を硫化銀へと変化させて銀を十分に固定化することが可能となる。なお、この知見に基づくとすれば、硫化亜鉛や硫化銅以外の硫化物であってＥＤＴＡやＤＴＰＡと安定した錯体を速やかに形成可能なものであれば硫化物添加工程にて採用するのに差し支えは無い。
Among the sulfides, zinc sulfide and copper sulfide are preferable. The reason is as follows.
The waste liquid as the liquid to be treated of the present embodiment contains silver, hydrogen peroxide, and at least one of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminetetraacetic acid (DTPA). As mentioned earlier, EDTA and DTPA are contained in the waste liquid in order to stabilize the solution (to coordinate EDTA and DTPA to silver ions so as not to make silver highly active). is there. When zinc sulfide or copper sulfide is added to the alkaline waste liquid in this state, zinc sulfide or copper sulfide is ionized into zinc ions, copper ions and sulfide ions as shown in the following reaction formula.
ZnS → Zn 2+ + S 2-
CuS → Cu 2+ + S 2-
The sulfide ion ( S2- ) binds to the silver ion in the waste liquid to generate silver sulfide, thereby immobilizing silver. On the other hand, zinc ions and copper ions quickly become stable chelate complexes with respect to EDTA and DTPA. For example, the complex formation constant of the complex of EDTA and silver is 7.32, whereas the complex formation constant of the complex of EDTA and zinc is 16.50, and the complex of EDTA and zinc is more stable (). Source: "Point Analytical Chemistry Exercise", p. 264, Written by Takuji Kawashima et al., Published by Hirokawa Shoten). It is considered that DTPA having a carbon skeleton similar to EDTA also has a complex formation constant similar to that of zinc, and copper ions also easily form a complex with EDTA and DTPA, and the complex is stable. ..
That is, the zinc ions and copper ions on the right side in the above reaction formula decrease due to the complexation with EDTA and DTPA. In that case, the reaction in the above reaction formula will be further biased to the right side, zinc sulfide and copper sulfide can be sufficiently ionized, and silver can be sufficiently changed to silver sulfide to sufficiently immobilize silver. It becomes. Based on this finding, any sulfide other than zinc sulfide or copper sulfide that can quickly form a stable complex with EDTA or DTPA may be used in the sulfide addition step. There is no.
（２．希釈工程）
希釈工程は被処理液を過酸化水素含有量が少ない液で希釈するものである。希釈工程を行うことにより、以下に示す加温工程において過酸化水素を自己分解させる際に発泡を少なくできる。
(2. Dilution step)
The dilution step is to dilute the liquid to be treated with a liquid having a low hydrogen peroxide content. By performing the dilution step, foaming can be reduced when hydrogen peroxide is autolyzed in the heating step shown below.
なお、希釈工程は以下に示す加温工程の前に行えばよく、先の硫化物添加工程の前に行っても構わない。
また、希釈工程において過酸化水素の濃度が３０ｇ／Ｌ以下、さらには２０ｇ／Ｌ以下となるまで希釈するのが好ましく、希釈工程にて用いる希釈液は、以下の加温工程〜固液分離工程を経た後の液体（例えばろ液）を使用するのが工業プロセス的に廃液処理量を減少させ、低コストでの処理が可能となり有利であり好ましい。
The dilution step may be performed before the heating step shown below, and may be performed before the previous sulfide addition step.
Further, it is preferable to dilute until the concentration of hydrogen peroxide becomes 30 g / L or less, further 20 g / L or less in the dilution step, and the diluent used in the dilution step is the following heating step to solid-liquid separation step. It is advantageous and preferable to use a liquid (for example, a filtrate) after passing through the above process because the amount of waste liquid to be treated can be reduced in an industrial process and the treatment can be performed at low cost.
（３．加温工程）
加温工程においては硫化物が添加された被処理液を加温して過酸化水素を除去する。加温を行うための具体的な手法や装置構成としては特に限定は無いが、分解までに要する時間と安全性を考慮すると、３０〜４０℃の範囲での加温を行うのが望ましい。
(3. Heating process)
In the heating step, the liquid to be treated to which sulfide is added is heated to remove hydrogen peroxide. The specific method and device configuration for heating are not particularly limited, but in consideration of the time required for decomposition and safety, it is desirable to perform heating in the range of 30 to 40 ° C.
（４．キレート剤添加工程）
キレート剤添加工程においては過酸化水素が除去された被処理液に対してピペラジン系キレート剤を添加する。ピペラジン系キレート剤の添加により、廃液中に残存する銀（イオン）を固定化することが可能となる。
また、廃液中にて銀が固定化されたもの（すなわち硫化銀）の粒子が粗大化されるという効果もある。粒子が粗大化されれば、後の固液分離（例えばろ過）工程において固体（ろ物）として硫化銀（銀含有物）を（ろ紙上）に残存させやすくなり、ひいては銀含有物を効率よく回収でき、最終的には銀の回収率を向上させることが可能となる。
なお、ピペラジン系キレート剤としては公知のもの（ピペラジンやその誘導体を含有するもの、例えば東ソー製 ＴＳ−３００、ＴＸ−３０、主成分 ジカリウム＝ピペラジン−１，４ビス（カルボジチオアート）等）を使用すればよい。また、添加量については特に限定は無いが廃液中の銀の等量以上が好ましい。
(4. Chelating agent addition step)
In the chelating agent addition step, a piperazine-based chelating agent is added to the liquid to be treated from which hydrogen peroxide has been removed. By adding a piperazine-based chelating agent, it becomes possible to immobilize silver (ions) remaining in the waste liquid.
It also has the effect of coarsening the particles of silver-immobilized (that is, silver sulfide) in the waste liquid. If the particles are coarsened, silver sulfide (silver-containing material) can easily remain on the filter paper as a solid (filter material) in the subsequent solid-liquid separation (for example, filtration) step, and the silver-containing material can be efficiently used. It can be recovered, and finally it becomes possible to improve the recovery rate of silver.
As a piperazine-based chelating agent, known ones (those containing piperazine or its derivatives, for example, TS-300, TX-30 manufactured by Tosoh, main component dipotassium = piperazine-1,4 bis (carbodithioate), etc.) are used. You can use it. The amount of silver added is not particularly limited, but is preferably equal to or more than the equivalent amount of silver in the waste liquid.
本実施形態においては、廃液に対して硫化物を添加して銀を固定化し、その上、加温工程を挟んで更に銀を固定化可能なピペラジン系キレート剤を添加することにも大きな特徴がある。
仮に、加温工程の前に、硫化物の代わりにピペラジン系キレート剤を廃液に添加すると、廃液中の銀の７０％程度しか固定化できないという結果が後述の実施例の項目にて示されている（図２のｉ）の棒グラフ）。これは過酸化水素の影響によりピペラジン系キレート剤が酸化分解されてしまっているものと推察される。
だからこそ、キレート剤添加工程は、加温工程によって過酸化水素を廃液から除去した後に行う。そして過酸化水素を廃液から安全に除去しかつ処理のコストを抑えるべく、同じく銀を固定化可能な硫化物を添加する。つまり、硫化物（銀の固定化剤）の添加によりほとんどの銀を固定化→加温→ピペラジン系キレート剤（銀の固定化剤）の添加により残りの銀を固定化、という一連の流れは、安全性の確保、被処理液の処理コスト抑制、さらに言うと銀の回収率の向上を図るという知見があったからこそ創出されたものである。そのため本実施形態における被処理液の処理方法としては上記の硫化物添加工程、加温工程、キレート剤添加工程の組み合わせに大きな特徴がある。その一方で、上記の希釈工程、そして以下の各工程は好適例として行う。
In the present embodiment, a major feature is that silver is immobilized by adding sulfide to the waste liquid, and further, a piperazine-based chelating agent capable of immobilizing silver is added with a heating step in between. is there.
As shown in the item of Examples described later, if a piperazine-based chelating agent is added to the waste liquid before the heating step, only about 70% of silver in the waste liquid can be immobilized. (I in FIG. 2) bar graph). It is presumed that this is because the piperazine chelating agent has been oxidatively decomposed by the influence of hydrogen peroxide.
That is why the chelating agent addition step is performed after removing hydrogen peroxide from the waste liquid by a heating step. Then, in order to safely remove hydrogen peroxide from the waste liquid and reduce the cost of treatment, a sulfide that can also immobilize silver is added. In other words, the sequence of immobilizing most of silver by adding sulfide (silver immobilizing agent) → heating → immobilizing the remaining silver by adding piperazine chelating agent (silver immobilizing agent) It was created because of the knowledge that it aims to ensure safety, reduce the treatment cost of the liquid to be treated, and further improve the silver recovery rate. Therefore, the method for treating the liquid to be treated in the present embodiment is characterized by a combination of the above-mentioned sulfide addition step, heating step, and chelating agent addition step. On the other hand, the above dilution step and each of the following steps are performed as preferable examples.
（５．固液分離工程（銀の回収方法））
固液分離工程においては、キレート剤添加工程後、被処理液を固液分離することにより、固体である銀含有物を回収する。固液分離は例えばろ過等により行われる。ろ過を行うための具体的な手法や装置構成としては特に限定は無い。銀の回収方法を実施する場合は、回収した銀含有物（硫化銀）から更に金属銀を回収する。その具体的な手法については公知のものを用いればよい。この金属銀の回収を含めて銀の回収方法（製造方法）であり、これまで述べてきた本発明の技術的思想が反映された発明である。
(5. Solid-liquid separation process (silver recovery method))
In the solid-liquid separation step, after the chelating agent addition step, the liquid to be treated is solid-liquid separated to recover the solid silver-containing material. Solid-liquid separation is performed, for example, by filtration or the like. There are no particular restrictions on the specific method or device configuration for performing filtration. When the method of recovering silver is carried out, metallic silver is further recovered from the recovered silver-containing material (silver sulfide). A known method may be used as the specific method. This is a silver recovery method (manufacturing method) including the recovery of metallic silver, and is an invention that reflects the technical idea of the present invention described so far.
（６．中和工程）
中和工程においては固液分離工程（例えばろ過工程）で生じた液体（例えばろ液）に酸を加えて中和する。ここで加えられる酸としては任意の公知のもので構わず例えば硫酸を採用しても構わない。また中和の際のｐＨについてはアルカリ性を中性ないし酸性とする程度のｐＨとすればよく、例えば後述の実施例の項目にて示すようにｐＨを７未満（好ましくは４．８以下）とすれば、（アルカリとしてアンモニアが使用されている場合は）アンモニアを硫安（硫酸アンモニウム）へと変化させることにより、以下の凝縮水処理工程にて処理対象となる凝縮水において、排水規制物質であるアンモニアの含有量を著しく低減させることが可能となる。
(6. Neutralization process)
In the neutralization step, an acid is added to the liquid (for example, filtrate) generated in the solid-liquid separation step (for example, filtration step) to neutralize. As the acid added here, any known acid may be used, and for example, sulfuric acid may be used. The pH at the time of neutralization may be such that the alkalinity is neutral to acidic. For example, as shown in the item of Examples described later, the pH is less than 7 (preferably 4.8 or less). By changing the ammonia to ammonium sulfate (ammonium sulfate) (when ammonia is used as the alkali), ammonia, which is a wastewater control substance, is used in the condensed water to be treated in the following condensed water treatment step. It is possible to significantly reduce the content of.
（７．蒸発濃縮工程）
蒸発濃縮工程においては、中和された液体（例えばろ液）を蒸発濃縮させ、蒸発により生じた凝縮水に含有されるホルムアルデヒドを除去する。ちなみにこのホルムアルデヒドは、過酸化水素が自己分解する際にＥＤＴＡやＤＴＰＡの側鎖が酸化分解されて生じるものと推察される。ホルムアルデヒドは排水規制物質であり放流前に除去すべき対象である。なお、近年、ヒートポンプを用いた蒸発濃縮装置が開発されており、比較的低コストで本実施形態を行える。
なお、蒸発濃縮により残存した濃縮物は任意の公知の手法にて処理すればよく、例えば産業廃棄物として処理してもよい。
(7. Evaporation concentration step)
In the evaporation concentration step, the neutralized liquid (for example, a filtrate) is evaporated and concentrated to remove formaldehyde contained in the condensed water generated by the evaporation. By the way, it is presumed that this formaldehyde is generated by oxidative decomposition of the side chains of EDTA and DTPA when hydrogen peroxide is autolyzed. Formaldehyde is a wastewater regulation substance and should be removed before it is released. In recent years, an evaporation concentrator using a heat pump has been developed, and this embodiment can be carried out at a relatively low cost.
The concentrate remaining after evaporation and concentration may be treated by any known method, and may be treated as industrial waste, for example.
（８．凝縮水処理工程）
ホルムアルデヒドの除去方法としては任意の公知の手法を採用すればよい。例えば好気性処理や嫌気性処理、ＲＯ膜処理等が挙げられる。好気性処理ならば、良好な処理水が得られ、環境変化にも強い。また、嫌気性処理ならば、好気性処理と比べ消費電力が低く、 余剰汚泥の発生も少ない。
(8. Condensed water treatment process)
Any known method may be adopted as the method for removing formaldehyde. For example, aerobic treatment, anaerobic treatment, RO membrane treatment and the like can be mentioned. With aerobic treatment, good treated water can be obtained and it is resistant to environmental changes. In addition, anaerobic treatment consumes less power than aerobic treatment and produces less excess sludge.
以上の各工程を経ることにより、廃液の処理中において、被処理液の処理コストを抑えることが可能となる。また、それに加え、銀の回収率を向上させることが可能となる。 By going through each of the above steps, it is possible to reduce the treatment cost of the liquid to be treated during the treatment of the waste liquid. In addition, it is possible to improve the silver recovery rate.
なお、本発明の技術的範囲は上述した実施の形態に限定されるものではなく、発明の構成要件やその組み合わせによって得られる特定の効果を導き出せる範囲において、種々の変更や改良を加えた形態も含む。例えば上記の各変形例の組み合わせや上記の実施形態にて例示した内容との組み合わせについても本発明の技術的思想の適用範囲である。 The technical scope of the present invention is not limited to the above-described embodiment, and various modifications and improvements may be made to the extent that a specific effect obtained by the constituent requirements of the invention and the combination thereof can be derived. Including. For example, the combination of each of the above modifications and the combination with the contents exemplified in the above embodiment is also within the scope of the technical idea of the present invention.
次に実施例を示し、本発明について具体的に説明する。本発明は、以下の実施例に限定されるものではない。 Next, an example will be shown and the present invention will be specifically described. The present invention is not limited to the following examples.
［試験条件］
（廃液組成）
金属−セラミック接合基板の製造の際の廃液を再現すべく、使用後の剥離液と同様の組成となるように、模擬液を調整した。調整した模擬液は、ＥＤＴＡ系とＤＴＰＡ系の２種類を各々用いた。模擬液の組成を表１に示す。
(Waste liquid composition)
In order to reproduce the waste liquid in the production of the metal-ceramic bonded substrate, the simulated liquid was adjusted so as to have the same composition as the stripping liquid after use. Two types of EDTA-based and DTPA-based simulated solutions were used. The composition of the simulated solution is shown in Table 1.
ＥＤＴＡ系の模擬液の調整は、以下のように行った。
硝酸銀（ＷＡＫＯ純薬工業）０．７９ｇ、ＥＤＴＡ・２Ｎａ・２Ｈ２Ｏ（ＤＯＪＩＮＤＯ）２５．５ｇ、塩化銅（II）二水和物（ＷＡＫＯ純薬工業）２．７ｇを蒸留水５００ ｍＬに溶解した。次に、２８％アンモニア水（ＷＡＫＯ純薬工業）９３ｍＬ、３０％過酸化水素水（ＷＡＫＯ純薬工業）１８２ｍＬを順次添加した後、蒸留水を添加して溶液を１Ｌに定量した。
The EDTA-based simulated solution was adjusted as follows.
Silver nitrate (WAKO Pure Chemical Industries) 0.79g, EDTA · 2Na · 2H 2 O (DOJINDO) 25.5g, dissolved copper (II) chloride dihydrate (WAKO Pure Chemical Industries) 2.7 g distilled water 500 mL did. Next, 93 mL of 28% ammonia water (WAKO Pure Pharmaceutical Industry) and 182 mL of 30% hydrogen peroxide solution (WAKO Pure Pharmaceutical Industry) were added in sequence, and then distilled water was added to quantify the solution to 1 L.
ＤＴＰＡ系の模擬液の調整は、以下の通り行った。
硝酸銀０．１１ｇ、ＤＴＰＡ（東京化成）２０ｇを蒸留水５００ｍＬに溶解した。次に、３０％過酸化水素水１８２ｍｌを添加した後、蒸留水を添加して１Ｌに定量した。
The DTPA-based simulated solution was adjusted as follows.
0.11 g of silver nitrate and 20 g of DTPA (Tokyo Kasei) were dissolved in 500 mL of distilled water. Next, after adding 182 ml of 30% hydrogen peroxide solution, distilled water was added and the amount was quantified to 1 L.
（分析装置）
本実施例においては図２に示すように銀固定化率（％）を算出している。銀固定化率は、模擬液に含有される銀（イオン）の量に対する、上記の固液分離（ろ過）工程で生じたろ液に含有される銀（イオン）の量の割合を１から減じたものに１００を乗じた値である。
ろ液の銀（イオン）の濃度の分析には、ＨＩＴＡＣＨＩ ＳＩＩ−５１００誘導結合プラズマ−原子発光分析装置（ＩＣＰ−ＡＥＳ）を用いた。
また、過酸化水素およびホルムアルデヒドの定量には共立デジタルパックテストを用いた。ホルムアルデヒドの精密分析は、蒸発濃縮により凝縮水を得た後、アセチルアセトン吸光光度法により行った。
(Analysis equipment)
In this embodiment, the silver immobilization rate (%) is calculated as shown in FIG. The silver immobilization rate was obtained by subtracting the ratio of the amount of silver (ions) contained in the filtrate generated in the above solid-liquid separation (filtration) step to the amount of silver (ions) contained in the simulated liquid from 1. It is a value obtained by multiplying a thing by 100.
A HITACHI SII-5100 inductively coupled plasma-atomic emission spectrometer (ICP-AES) was used to analyze the silver (ion) concentration in the filtrate.
The Kyoritsu Digital Pack Test was used to quantify hydrogen peroxide and formaldehyde. The precise analysis of formaldehyde was carried out by the acetylacetone absorptiometry after obtaining condensed water by evaporation and concentration.
（微生物の馴養）
凝縮水に含有されるホルムアルデヒドの除去においては、好気性処理を採用しつつ、以下の手法を採用した。凝縮水のｐＨは、事前に６〜７の範囲になるように調整した。
生物担体としての５ｍｍ角のスポンジを水に対して２０体積％程度加えたものに対し、ＤＯＷＡハイテック株式会社から採取した種汚泥を加えた。更に、微量金属、アンモニア、エタノールを添加し、室温で２週間程度馴養した。
(Microbial acclimatization)
In removing formaldehyde contained in condensed water, the following method was adopted while adopting aerobic treatment. The pH of the condensed water was adjusted in advance so as to be in the range of 6 to 7.
About 20% by volume of a 5 mm square sponge as a biological carrier was added to water, and seed sludge collected from DOWA Hightech Co., Ltd. was added. Further, trace metals, ammonia and ethanol were added, and the mixture was allowed to acclimatize at room temperature for about 2 weeks.
（被処理液の処理方法）
上記のように用意した２種のＥＤＴＡ系とＤＴＰＡ系の模擬液を体積比２：１で混合したもの５００ｍＬに対し、２００ｍｇ／ｍＬの硫化亜鉛（ＷＡＫＯ純薬工業）スラリーを２ｍＬ添加した（硫化物添加工程）。このスラリーを添加した液をＡ液と呼ぶ。
(Treatment method of liquid to be treated)
2 mL of 200 mg / mL zinc sulfide (WAKO Pure Chemical Industries) slurry was added to 500 mL of a mixture of the two EDTA-based and DTPA-based simulated solutions prepared as described above at a volume ratio of 2: 1 (sulfurization). Material addition process). The liquid to which this slurry is added is called liquid A.
次に、Ａ液を５００ｍＬ分取し、水を１Ｌ加えて３倍に希釈した。この液をＢ液と呼ぶ。 Next, 500 mL of solution A was taken, and 1 L of water was added to dilute it 3-fold. This liquid is called liquid B.
その後、５ＬビーカーにＢ液を注ぎ、湯浴中で加温しながら撹拌した（加温工程）。攪拌羽は、二段タービン羽を用いて、回転数を２００ｒｐｍとした。 Then, solution B was poured into a 5 L beaker and stirred while heating in a hot water bath (heating step). As the stirring blade, a two-stage turbine blade was used, and the rotation speed was set to 200 rpm.
Ｂ液の残存過酸化水素濃度が１００ｍｇ／Ｌ以下になったことを確認した後、Ａ液に対して２ｍＬ／Ｌ（Ａ液を３倍に希釈したＢ液に対しては２／３である０．６７ｍＬ／Ｌ）となるようにピペラジン系キレート剤（東ソー、ＴＳ−３００）を添加した（キレート剤添加工程）。 After confirming that the residual hydrogen peroxide concentration in solution B was 100 mg / L or less, it was 2 mL / L with respect to solution A (2/3 with respect to solution B in which solution A was diluted 3 times). A piperazine-based chelating agent (Tosoh, TS-300) was added so as to be 0.67 mL / L) (chelating agent addition step).
ピペラジン系キレート剤の添加後、１５分以内で攪拌を継続し、不溶性錯体を形成した。次に、２０００ｍｇ／Ｌのアニオン高分子凝集剤を１ｍＬ添加し、フロックを形成した。その後、液相と固相の分離を行うべく、加圧ろ過を行った（ろ過工程）。具体的には、Ｂ液を０．２〜０．３５ＭＰａの範囲にて加圧し、孔径３μｍのフィルターでろ過した。ろ液のうち５００ｍＬを次の中和工程に供した。なお、ろ液の残りは、後述の各種検証試験での別サイクルにおける希釈工程にてＡ液を希釈する際に使用する希釈液とした。 After the addition of the piperazine chelating agent, stirring was continued within 15 minutes to form an insoluble complex. Next, 1 mL of 2000 mg / L of anionic polymer flocculant was added to form flocs. Then, pressure filtration was performed to separate the liquid phase and the solid phase (filtration step). Specifically, the solution B was pressurized in the range of 0.2 to 0.35 MPa and filtered through a filter having a pore size of 3 μm. 500 mL of the filtrate was subjected to the next neutralization step. The rest of the filtrate was used as the diluent used when diluting the solution A in the dilution step in another cycle in various verification tests described later.
次に、ろ液５００ｍＬをｐＨ４．８になるよう９８％硫酸で中和した（中和工程）。中和に要した硫酸量は１０ｇであった。 Next, 500 mL of the filtrate was neutralized with 98% sulfuric acid so as to have a pH of 4.8 (neutralization step). The amount of sulfuric acid required for neutralization was 10 g.
次に、中和液を蒸発濃縮装置（東京理化器械 ＮＶＣ−２０００）にて６９℃、２１０ｈＰａの減圧条件に設定し、蒸発により生成される凝縮液と、残存する濃縮物とに分離した（蒸発濃縮工程）。濃縮倍率は析出物がないか確認しながら１０倍を目途とした。そして、凝縮水に含有されるホルムアルデヒドを分解するため、凝縮水に栄養剤とリン酸を添加後、希苛性（希薄な苛性ソーダ溶液）でｐＨ７程度に調整し、生物担体を全体液量の２０体積％で添加し、ＤＯ（溶存酸素量）が９ｍｇ／Ｌとなるように曝気しながら処理を行った（凝縮水処理工程）。なお、処理は室温で行い液温は２１℃とした。 Next, the neutralizing solution was set to a reduced pressure condition of 69 ° C. and 210 hPa by an evaporation concentrator (Tokyo Rika Kikai NVC-2000), and the condensate produced by evaporation and the remaining concentrate were separated (evaporation). Concentration step). The concentration ratio was set to 10 times while checking for precipitates. Then, in order to decompose the formaldehyde contained in the condensed water, after adding a nutrient and a phosphoric acid to the condensed water, the pH is adjusted to about 7 with aeration (dilute caustic soda solution), and the biological carrier is 20 volumes of the total liquid volume. The treatment was carried out while aerating so that the DO (dissolved oxygen amount) was 9 mg / L (condensed water treatment step). The treatment was carried out at room temperature and the liquid temperature was 21 ° C.
［本実施例に係る結果］
本実施例によれば、塩酸のような設備コストが嵩む要因となる物質を採用せずとも、過酸化水素による突沸や液こぼれも無く、作業中の安全性を確保することができた。また、後掲の図２に示すように９９％以上の高収率で銀を回収できた。
[Results of this example]
According to this embodiment, even if a substance such as hydrochloric acid, which causes an increase in equipment cost, is not used, there is no sudden boiling or spillage due to hydrogen peroxide, and safety during work can be ensured. Further, as shown in FIG. 2 described later, silver could be recovered in a high yield of 99% or more.
［各種検証結果］
本実施例の効果は示されたが、上記の効果をサポートする各種試験も行った。以下、各種検証結果について説明する。以降において特記の無い事項は本実施例で述べた内容と同様である。
[Various verification results]
Although the effects of this example were shown, various tests were also conducted to support the above effects. The various verification results will be described below. The matters not otherwise specified in the following are the same as those described in this embodiment.
（硫化物添加工程およびキレート剤添加工程の技術的意義）
Ａ液を３倍に希釈したＢ液に対し、各条件および各試薬にて銀を固定化した際の銀固定化率との関係を棒グラフとして図２に示す。棒グラフの左から以下の条件および試薬を示す。
ｉ）加温工程前のＢ液に対してピペラジン系キレート剤（ＴＳ−３００）を添加
ii）加温工程前のＢ液に対して硫化亜鉛を添加
iii）ii）に対して加温工程を行ったもの
iv）上記実施例（硫化物添加工程→加温工程→キレート剤添加工程）
本実施形態において説明したように、ｉ）においては、過酸化水素を除去する加温工程前ではピペラジン系キレート剤は過酸化水素による酸化分解の影響を受け、銀の固定化という効果を十分に奏しない。
その一方、ii）においては、硫化物である硫化亜鉛ならば、加温工程前のＢ液においても９７％以上の銀が固定されていた。
また、iii）においては、過酸化水素を除去する加温工程後も、硫化銀は溶解することなく、９８％以上の銀が回収された。
iv）においては、硫化亜鉛を添加した後に加温工程を行った後で、更にピペラジン系キレート剤を添加することで、９９％以上の高収率で銀を回収できた。
その結果、硫化物（銀の固定化剤）の添加によりほとんどの銀を固定化→加温→ピペラジン系キレート剤（銀の固定化剤）の添加により残りの銀を固定化、という一連の流れに有意性があることが証明された。
(Technical significance of sulfide addition step and chelating agent addition step)
FIG. 2 shows a bar graph showing the relationship between the silver immobilization rate when silver is immobilized under each condition and each reagent with respect to the B solution obtained by diluting the solution A three times. The following conditions and reagents are shown from the left of the bar graph.
i) Add a piperazine chelating agent (TS-300) to solution B before the heating process.
ii) Add zinc sulfide to solution B before the heating process
iii) A heating process for ii)
iv) The above embodiment (sulfide addition step → heating step → chelating agent addition step)
As described in the present embodiment, in i), the piperazine-based chelating agent is affected by oxidative decomposition by hydrogen peroxide before the heating step of removing hydrogen peroxide, and has a sufficient effect of immobilizing silver. Does not play.
On the other hand, in ii), in the case of zinc sulfide, which is a sulfide, 97% or more of silver was fixed even in the liquid B before the heating step.
Further, in iii), 98% or more of silver was recovered without dissolving silver sulfide even after the heating step of removing hydrogen peroxide.
In iv), silver could be recovered in a high yield of 99% or more by adding a piperazine-based chelating agent after performing a heating step after adding zinc sulfide.
As a result, most of the silver is immobilized by adding sulfide (silver fixing agent) → heating → the remaining silver is immobilized by adding a piperazine chelating agent (silver fixing agent). Proved to be significant.
（加温工程および希釈工程の技術的意義）
Ａ液を３倍に希釈したＢ液における過酸化水素の分解時間（すなわち加温時間）とＢ液の温度との関係を棒グラフとして図３に示す。Ｂ液の温度が高いほど、短時間で過酸化水素が分解した。２０℃では、分解までに一昼夜を要した。３０℃、４０℃ではそれぞれ４．５時間、２時間であった。
つまり、加温工程を行うことにより処理時間を大幅に短縮できることが証明された。
(Technical significance of heating process and dilution process)
FIG. 3 shows the relationship between the decomposition time of hydrogen peroxide (that is, the heating time) and the temperature of the B solution in the B solution obtained by diluting the A solution three times as a bar graph. The higher the temperature of Liquid B, the shorter the time it took for hydrogen peroxide to decompose. At 20 ° C, it took a whole day and night to decompose. It was 4.5 hours and 2 hours at 30 ° C. and 40 ° C., respectively.
That is, it was proved that the processing time can be significantly shortened by performing the heating process.
更に、装置の液温設定を４０℃としたときの過酸化水素濃度と温度変化の関係を図４に示す。■は過酸化水素水の濃度（ｍｇ／Ｌ：右辺）を示し、〇はＢ液の温度（℃：左辺）を示す。１１０分時点で、過酸化水素濃度の急激な減少（すなわち急速な過酸化水素の分解）および液温の上昇が見られた。具体的には、過酸化水素濃度は、１３ｇ／Ｌから１００ｍｇ／Ｌ未満に低下した。ただ、過酸化水素の分解に伴う液温上昇は４℃以下であり、最高液温は４５℃以下に抑えられていた。なお、突沸や液こぼれが起きないか目視観測も行ったが、液面上昇は初期液量の５％以下に留めることができた。
この良好な結果は、硫化物添加工程によって銀を十分に固定化し、しかも好適には被処理液における過酸化水素の濃度が２０ｇ／Ｌ以下となるまで希釈されたＢ液を用意したことに起因すると考えられる。
Further, FIG. 4 shows the relationship between the hydrogen peroxide concentration and the temperature change when the liquid temperature setting of the apparatus is set to 40 ° C. ■ indicates the concentration of hydrogen peroxide solution (mg / L: right side), and ◯ indicates the temperature of solution B (° C: left side). At 110 minutes, a sharp decrease in hydrogen peroxide concentration (ie, rapid decomposition of hydrogen peroxide) and an increase in liquid temperature were observed. Specifically, the hydrogen peroxide concentration decreased from 13 g / L to less than 100 mg / L. However, the rise in liquid temperature due to the decomposition of hydrogen peroxide was 4 ° C or lower, and the maximum liquid temperature was suppressed to 45 ° C or lower. Visual observation was also carried out to see if bumping or spilling occurred, but the liquid level rise could be kept below 5% of the initial liquid volume.
This good result is due to the fact that silver was sufficiently immobilized by the sulfide addition step, and more preferably, liquid B was prepared, which was diluted until the concentration of hydrogen peroxide in the liquid to be treated became 20 g / L or less. It is thought that.
（中和工程および蒸発濃縮工程の技術的意義）
中和工程後であって蒸発濃縮工程前のＢ液のｐＨ、その後の凝縮水処理工程における凝縮水の水質との関係を表２に示す。
一方、十分な中和が行われた結果であるｐＨ４．８のＢ液に対して蒸発濃縮を行った場合、アンモニアは濃縮液側に固定され、凝縮水のアンモニアの濃度は２ｐｐｍ未満であった。なお、凝縮水におけるＣＯＤ濃度は１５０ｐｐｍであり、該ＣＯＤの成分を調査した結果、ホルムアルデヒドであることを確認した。
つまり、Ｂ液をアルカリ性から中性ないし酸性（ｐＨ７．０未満）へと十分に中和する中和工程を経ることにより、凝縮水に対し、排水規制物質であるアンモニアを含有させることを抑制することができた。
(Technical significance of neutralization step and evaporation concentration step)
Table 2 shows the relationship between the pH of the liquid B after the neutralization step and before the evaporation and concentration step, and the water quality of the condensed water in the subsequent condensed water treatment step.
On the other hand, when the solution B having a pH of 4.8, which was the result of sufficient neutralization, was subjected to evaporation concentration, ammonia was fixed on the concentration solution side, and the concentration of ammonia in the condensed water was less than 2 ppm. .. The COD concentration in the condensed water was 150 ppm, and as a result of investigating the components of the COD, it was confirmed that it was formaldehyde.
That is, by undergoing a neutralization step of sufficiently neutralizing the liquid B from alkaline to neutral to acidic (pH less than 7.0), it is possible to suppress the inclusion of ammonia, which is a wastewater regulating substance, in the condensed water. I was able to.
（凝縮水処理工程の技術的意義）
凝縮水に対し、本実施例に記載した手法での生物処理（好気性処理）を行った結果を図５に示す。好気性処理の結果、ホルムアルデヒドの濃度は３．５時間で３０ｍｇ／Ｌから０ｍｇ／Ｌになることを確認した。
つまり、凝縮水処理工程により、凝縮水に含有されるホルムアルデヒドを除去することに成功したことが明らかとなった。
(Technical significance of condensed water treatment process)
FIG. 5 shows the results of biological treatment (aerobic treatment) of condensed water by the method described in this example. As a result of the aerobic treatment, it was confirmed that the concentration of formaldehyde changed from 30 mg / L to 0 mg / L in 3.5 hours.
That is, it was clarified that the formaldehyde contained in the condensed water was successfully removed by the condensed water treatment step.
Claims (10)
被処理液に対して硫化物を添加する硫化物添加工程と、
硫化物が添加された被処理液を加温して過酸化水素を除去する加温工程と、
過酸化水素が除去された被処理液に対してピペラジン系キレート剤を添加するキレート剤添加工程と、
を有する、被処理液の処理方法。 A method for treating an alkaline object to be treated, which comprises silver, hydrogen peroxide, and a chelating agent which is at least one of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminetetraacetic acid (DTPA).
A sulfide addition step of adding sulfide to the liquid to be treated,
A heating process that heats the liquid to be treated to which sulfide is added to remove hydrogen peroxide, and
A chelating agent addition step of adding a piperazine-based chelating agent to the liquid to be treated from which hydrogen peroxide has been removed, and
A method for treating a liquid to be treated.
を有する、請求項１に記載の被処理液の処理方法。 After the chelating agent addition step, a solid-liquid separation step of recovering a solid silver-containing substance by solid-liquid separation of the liquid to be treated,
The method for treating a liquid to be treated according to claim 1.
を有する、請求項２に記載の被処理液の処理方法。 A neutralization step of adding an acid to the liquid generated in the solid-liquid separation step to neutralize the liquid,
The method for treating a liquid to be treated according to claim 2.
を有する、請求項３に記載の被処理液の処理方法。 An evaporative concentration step of evaporating and concentrating the liquid neutralized in the neutralization step,
The method for treating a liquid to be treated according to claim 3.
を有する、請求項４に記載の被処理液の処理方法。 A condensed water treatment step of removing formaldehyde contained in the condensed water generated by evaporation concentration in the evaporation concentration step, and a condensed water treatment step.
The method for treating a liquid to be treated according to claim 4.
前記希釈工程における希釈液として、前記固液分離工程で生じた液体の一部を用いる、請求項６に記載の被処理液の処理方法。 After the chelating agent addition step, a solid-liquid separation step of recovering a solid silver-containing substance by solid-liquid separation of the liquid to be treated is provided.
The method for treating a liquid to be treated according to claim 6, wherein a part of the liquid generated in the solid-liquid separation step is used as the diluent in the dilution step.
被処理液に対して硫化物を添加する硫化物添加工程と、
硫化物が添加された被処理液を加温して過酸化水素を除去する加温工程と、
過酸化水素が除去された被処理液に対してピペラジン系キレート剤を添加するキレート剤添加工程と、
キレート剤添加工程後、被処理液を固液分離することにより、固体である銀含有物を回収する固液分離工程と、
銀含有物から銀を回収する銀回収工程と、
を有する、銀の回収方法。 A method for recovering silver from an alkaline treatment solution containing silver, hydrogen peroxide, and a chelating agent that is at least one of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminetetraacetic acid (DTPA).
A sulfide addition step of adding sulfide to the liquid to be treated,
A heating process that heats the liquid to be treated to which sulfide is added to remove hydrogen peroxide, and
A chelating agent addition step of adding a piperazine-based chelating agent to the liquid to be treated from which hydrogen peroxide has been removed, and
After the chelating agent addition step, the solid-liquid separation step of recovering the solid silver-containing material by solid-liquid separation of the liquid to be treated,
A silver recovery process that recovers silver from silver-containing materials,
A method of collecting silver.
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