JP7486294B2 - Cleaning solution, method for producing cleaning solution, and method for cleaning equipment - Google Patents
Cleaning solution, method for producing cleaning solution, and method for cleaning equipment Download PDFInfo
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- JP7486294B2 JP7486294B2 JP2019164177A JP2019164177A JP7486294B2 JP 7486294 B2 JP7486294 B2 JP 7486294B2 JP 2019164177 A JP2019164177 A JP 2019164177A JP 2019164177 A JP2019164177 A JP 2019164177A JP 7486294 B2 JP7486294 B2 JP 7486294B2
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- 238000004140 cleaning Methods 0.000 title claims description 156
- 238000000034 method Methods 0.000 title claims description 28
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 claims description 58
- 229910052751 metal Inorganic materials 0.000 claims description 53
- 239000002184 metal Substances 0.000 claims description 53
- 239000000126 substance Substances 0.000 claims description 53
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 48
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 claims description 43
- 239000004310 lactic acid Substances 0.000 claims description 29
- 235000014655 lactic acid Nutrition 0.000 claims description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 29
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical group [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 claims description 22
- 229910052946 acanthite Inorganic materials 0.000 claims description 18
- XUARKZBEFFVFRG-UHFFFAOYSA-N silver sulfide Chemical compound [S-2].[Ag+].[Ag+] XUARKZBEFFVFRG-UHFFFAOYSA-N 0.000 claims description 17
- 229940056910 silver sulfide Drugs 0.000 claims description 17
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 11
- 239000011347 resin Substances 0.000 claims description 6
- 229920005989 resin Polymers 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 5
- 239000000243 solution Substances 0.000 description 87
- 239000007788 liquid Substances 0.000 description 40
- 239000012528 membrane Substances 0.000 description 35
- 150000001875 compounds Chemical class 0.000 description 23
- 239000007787 solid Substances 0.000 description 20
- 239000000203 mixture Substances 0.000 description 17
- 229910052709 silver Inorganic materials 0.000 description 16
- 239000004332 silver Substances 0.000 description 16
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 15
- 238000001914 filtration Methods 0.000 description 14
- 230000004907 flux Effects 0.000 description 13
- 238000012360 testing method Methods 0.000 description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 9
- 229910052802 copper Inorganic materials 0.000 description 9
- 239000010949 copper Substances 0.000 description 9
- 239000005749 Copper compound Substances 0.000 description 8
- 239000000654 additive Substances 0.000 description 8
- 150000001880 copper compounds Chemical class 0.000 description 8
- 239000012510 hollow fiber Substances 0.000 description 8
- 229940100890 silver compound Drugs 0.000 description 8
- 150000003379 silver compounds Chemical class 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000011148 porous material Substances 0.000 description 7
- 230000000536 complexating effect Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 150000002506 iron compounds Chemical class 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 150000003752 zinc compounds Chemical class 0.000 description 6
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 5
- 125000000217 alkyl group Chemical group 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 5
- -1 lactate ions Chemical class 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- 229910052725 zinc Inorganic materials 0.000 description 5
- 239000011701 zinc Substances 0.000 description 5
- 125000004432 carbon atom Chemical group C* 0.000 description 4
- 238000004090 dissolution Methods 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 229910001385 heavy metal Inorganic materials 0.000 description 3
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000005416 organic matter Substances 0.000 description 3
- 239000007800 oxidant agent Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- MBMLMWLHJBBADN-UHFFFAOYSA-N Ferrous sulfide Chemical compound [Fe]=S MBMLMWLHJBBADN-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 239000005083 Zinc sulfide Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 239000004312 hexamethylene tetramine Substances 0.000 description 2
- 235000010299 hexamethylene tetramine Nutrition 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 239000012466 permeate Substances 0.000 description 2
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 description 2
- 239000012085 test solution Substances 0.000 description 2
- 229910052984 zinc sulfide Inorganic materials 0.000 description 2
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 2
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 description 1
- RYYXDZDBXNUPOG-UHFFFAOYSA-N 4,5,6,7-tetrahydro-1,3-benzothiazole-2,6-diamine;dihydrochloride Chemical compound Cl.Cl.C1C(N)CCC2=C1SC(N)=N2 RYYXDZDBXNUPOG-UHFFFAOYSA-N 0.000 description 1
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 1
- 239000005751 Copper oxide Substances 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 235000011054 acetic acid Nutrition 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- BJEPYKJPYRNKOW-UHFFFAOYSA-N alpha-hydroxysuccinic acid Natural products OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000011001 backwashing Methods 0.000 description 1
- KDYFGRWQOYBRFD-NUQCWPJISA-N butanedioic acid Chemical compound O[14C](=O)CC[14C](O)=O KDYFGRWQOYBRFD-NUQCWPJISA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 235000015165 citric acid Nutrition 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- BERDEBHAJNAUOM-UHFFFAOYSA-N copper(I) oxide Inorganic materials [Cu]O[Cu] BERDEBHAJNAUOM-UHFFFAOYSA-N 0.000 description 1
- KRFJLUBVMFXRPN-UHFFFAOYSA-N cuprous oxide Chemical compound [O-2].[Cu+].[Cu+] KRFJLUBVMFXRPN-UHFFFAOYSA-N 0.000 description 1
- 229940112669 cuprous oxide Drugs 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 125000005843 halogen group Chemical group 0.000 description 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 239000001630 malic acid Substances 0.000 description 1
- 235000011090 malic acid Nutrition 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000001728 nano-filtration Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000011085 pressure filtration Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 229910001923 silver oxide Inorganic materials 0.000 description 1
- YPNVIBVEFVRZPJ-UHFFFAOYSA-L silver sulfate Chemical compound [Ag+].[Ag+].[O-]S([O-])(=O)=O YPNVIBVEFVRZPJ-UHFFFAOYSA-L 0.000 description 1
- 229910000367 silver sulfate Inorganic materials 0.000 description 1
- FSJWWSXPIWGYKC-UHFFFAOYSA-M silver;silver;sulfanide Chemical compound [SH-].[Ag].[Ag+] FSJWWSXPIWGYKC-UHFFFAOYSA-M 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 150000004763 sulfides Chemical class 0.000 description 1
- IOIOILDYKMQXSF-UHFFFAOYSA-N sulfuric acid;thiourea Chemical compound NC(N)=S.OS(O)(=O)=O IOIOILDYKMQXSF-UHFFFAOYSA-N 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
Description
本発明は、洗浄液、その製造方法及び前記洗浄液を利用した設備の洗浄方法に関する。 The present invention relates to a cleaning solution, a method for producing the same, and a method for cleaning equipment using the cleaning solution.
銅や銀等の重金属類を含む廃水は環境汚染の懸念があり、これら重金属類を適切に分離し、廃水を浄化してから放流する必要がある。従来、そのような廃水の処理方法として、硫化水素などの硫化剤を添加して重金属類を硫化物の形で沈殿させ、固液分離する方法が知られている（特許文献１）。 Wastewater containing heavy metals such as copper and silver is a concern for environmental pollution, and it is necessary to properly separate these heavy metals and purify the wastewater before discharging it. A method for treating such wastewater that involves adding a sulfiding agent such as hydrogen sulfide to precipitate the heavy metals in the form of sulfides and then performing solid-liquid separation is known (Patent Document 1).
本発明者はこのようなプロセスについて、コスト、煩雑な操作の回避、作業の安全性の確保などを課題として改善を検討し、所定の金属を含有する被処理液に、中性ないしアルカリ性条件下で硫化銅を添加し、前記金属を硫化物として沈殿させ、得られたスラリーを固液分離する被処理液の処理方法を発明し、出願を行った（特許文献２）。 The inventors have investigated ways to improve this process, focusing on issues such as cost, avoiding complicated operations, and ensuring work safety, and have invented and filed a patent application for a method for treating a liquid containing a specific metal, in which copper sulfide is added under neutral or alkaline conditions to the liquid, causing the metal to precipitate as a sulfide, and the resulting slurry is separated into solid and liquid (Patent Document 2).
なお、非特許文献１には、金および銀鉱石に対して、硫酸酸性下でチオ尿素を添加し、これらを溶解することが記載されている。特許文献３には、さび除去剤組成物として、シュウ酸と二酸化チオ尿素を含み、有機酸として酢酸、乳酸、クエン酸、コハク酸、リンゴ酸を含んでもよい組成物が記載されている。 Non-Patent Document 1 describes the addition of thiourea to gold and silver ores under sulfuric acid acidity to dissolve them. Patent Document 3 describes a rust remover composition that contains oxalic acid and thiourea dioxide, and may contain acetic acid, lactic acid, citric acid, succinic acid, or malic acid as an organic acid.
本発明者は、上記特許文献２に開示されるプロセスで、スラリーの固液分離工程をフィルター（デッドエンド型又はクロスフロー型（中空糸膜））により実施する形態で、銀を含む被処理液を処理することを検討した。そして、当該処理を長期操業していると、フィルターが固形物で詰まってしまうことを知見した。この固形物は、硫化銀及び未反応の硫化銅で構成されていると考えられる。 The present inventors have investigated the treatment of a silver-containing liquid to be treated in the process disclosed in the above-mentioned Patent Document 2, in which the solid-liquid separation step of the slurry is carried out using a filter (dead-end type or cross-flow type (hollow fiber membrane)). They have found that when this treatment is operated for a long period of time, the filter becomes clogged with solid matter. It is believed that this solid matter is composed of silver sulfide and unreacted copper sulfide.
このような場合には通常、定期的に水又は圧縮空気あるいはその両方を用いて、フィルターの逆洗浄を行い、固形物をフィルターの膜面から除去する。しかし、逆洗浄では、完全に混合物を除去できなかった。このため、操業を継続すると、結局フィルターの閉塞が発生してしまった。フィルターが閉塞すると、以下の問題が生じる。 In such cases, the filter is usually backwashed periodically using water or compressed air or both to remove the solids from the filter membrane surface. However, backwashing does not completely remove the mixture. As a result, continued operation eventually leads to filter blockage. When the filter becomes blocked, the following problems occur:
１．フィルターの透過流量が下がる（スラリー処理量が低下し、プロセス全体の処理効率が低下する）。
２．フィルターの交換が必要となる（コスト，作業量増加）。
1. The filter permeation flow rate decreases (the slurry throughput decreases, and the overall process efficiency decreases).
2. Filters need to be replaced (increased cost and labor).
本発明は、これらの問題を解決するため、フィルターに付着した硫化銀及び硫化銅などの金属物質を溶解除去し、フィルターの膜性能を回復させることができる洗浄液を提供することを課題とする。 To solve these problems, the present invention aims to provide a cleaning solution that can dissolve and remove metal substances such as silver sulfide and copper sulfide that adhere to the filter and restore the membrane performance of the filter.
本発明者らは上記課題を解決するために鋭意検討した結果、乳酸、チオウレア構造を有する化合物、硫酸及び水を含有する洗浄液が、前記の金属物質を溶解除去するのに好適であることを見出し、本発明を完成するに至った。なお前記洗浄液は、フィルターに限らず前記金属物質で汚染した各種の設備の洗浄に適用可能である。 As a result of intensive research into solving the above problems, the inventors discovered that a cleaning solution containing lactic acid, a compound having a thiourea structure, sulfuric acid, and water is suitable for dissolving and removing the above-mentioned metal substances, and thus completed the present invention. The above-mentioned cleaning solution can be used to clean not only filters, but also various types of equipment contaminated with the above-mentioned metal substances.
すなわち本発明は、以下のとおりである。
［１］乳酸、チオウレア構造を有する化合物、硫酸及び水を含有する洗浄液。
That is, the present invention is as follows.
[1] A cleaning solution containing lactic acid, a compound having a thiourea structure, sulfuric acid, and water.
［２］前記洗浄液中の乳酸の含有量が、１～５０質量％である、［１］に記載の洗浄液。 [2] The cleaning solution according to [1], wherein the content of lactic acid in the cleaning solution is 1 to 50% by mass.
［３］前記洗浄液中のチオウレア構造を有する化合物の含有量が、１～１５質量％である、［１］又は［２］に記載の洗浄液。 [3] The cleaning solution according to [1] or [2], wherein the content of the compound having a thiourea structure in the cleaning solution is 1 to 15 mass %.
［４］前記洗浄液中の硫酸の含有量が、０．０５～１０質量％である、［１］～［３］のいずれかに記載の洗浄液。 [4] A cleaning solution according to any one of [1] to [3], in which the content of sulfuric acid in the cleaning solution is 0.05 to 10 mass %.
［５］前記洗浄液中の乳酸、チオウレア構造を有する化合物、硫酸及び水の含有量の合計が、９０質量％以上である、［１］～［４］のいずれかに記載の洗浄液。 [5] The cleaning solution according to any one of [1] to [4], wherein the total content of lactic acid, the compound having a thiourea structure, sulfuric acid, and water in the cleaning solution is 90% by mass or more.
［６］前記チオウレア構造を有する化合物が、下記一般式（１）で表される化合物である、［１］～［５］のいずれかに記載の洗浄液：
［７］銀、銀化合物、銅、銅化合物、鉄、鉄化合物、亜鉛および亜鉛化合物からなる群より選ばれる少なくとも１種の金属物質を溶解除去するために使用される、［１］～［６］のいずれかに記載の洗浄液。 [7] A cleaning solution according to any one of [1] to [6], which is used to dissolve and remove at least one metal substance selected from the group consisting of silver, silver compounds, copper, copper compounds, iron, iron compounds, zinc, and zinc compounds.
［８］銀、銀化合物、銅、銅化合物、鉄、鉄化合物、亜鉛および亜鉛化合物からなる群より選ばれる少なくとも１種の金属物質が付着した設備を洗浄するために使用される、［１］～［６］のいずれかに記載の洗浄液。 [8] A cleaning solution according to any one of [1] to [6], which is used to clean equipment having at least one metal substance attached thereto, selected from the group consisting of silver, silver compounds, copper, copper compounds, iron, iron compounds, zinc, and zinc compounds.
［９］前記銀化合物が硫化銀であり、前記銅化合物が硫化銅である、［７］又は［８］に記載の洗浄液。 [9] The cleaning solution according to [7] or [8], wherein the silver compound is silver sulfide and the copper compound is copper sulfide.
［１０］乳酸、チオウレア構造を有する化合物、硫酸及び水を混合する工程を有する、洗浄液の製造方法。 [10] A method for producing a cleaning solution, comprising a step of mixing lactic acid, a compound having a thiourea structure, sulfuric acid, and water.
［１１］前記洗浄液中の、前記乳酸の含有量が１～５０質量％、前記チオウレア構造を有する化合物の含有量が１～１５質量％、前記硫酸の含有量が０．０５～１０質量％、これら３成分及び水の含有量の合計が９０質量％以上となる割合で、前記乳酸、チオウレア構造を有する化合物、硫酸及び水を混合する、［１０］に記載の洗浄液の製造方法。 [11] The method for producing a cleaning solution according to [10], in which the lactic acid, the compound having a thiourea structure, sulfuric acid, and water are mixed in such a ratio that the content of the lactic acid in the cleaning solution is 1 to 50% by mass, the content of the compound having a thiourea structure is 1 to 15% by mass, the content of the sulfuric acid is 0.05 to 10% by mass, and the total content of these three components and water is 90% by mass or more.
［１２］前記洗浄液が、銀、銀化合物、銅、銅化合物、鉄、鉄化合物、亜鉛および亜鉛化合物からなる群より選ばれる少なくとも１種の金属物質が付着した設備を洗浄するために使用される、［１０］又は［１１］に記載の洗浄液の製造方法。 [12] The method for producing a cleaning solution according to [10] or [11], wherein the cleaning solution is used to clean equipment having at least one metal substance attached thereto, selected from the group consisting of silver, silver compounds, copper, copper compounds, iron, iron compounds, zinc, and zinc compounds.
［１３］前記設備がフィルターである、［１２］に記載の洗浄液の製造方法。 [13] The method for producing a cleaning solution according to [12], wherein the equipment is a filter.
［１４］銀、銀化合物、銅、銅化合物、鉄、鉄化合物、亜鉛および亜鉛化合物からなる群より選ばれる少なくとも１種の金属物質が付着した設備に［１］～［９］のいずれかに記載の洗浄液を接触させて前記金属物質を溶解除去する、設備の洗浄方法。 [14] A method for cleaning equipment, comprising contacting equipment having at least one metal substance attached thereto selected from the group consisting of silver, silver compounds, copper, copper compounds, iron, iron compounds, zinc, and zinc compounds with the cleaning solution described in any one of [1] to [9] to dissolve and remove the metal substance.
［１５］前記設備がフィルターであり、該フィルターに前記洗浄液を通液することで前記金属物質を溶解除去する、［１４］に記載の設備の洗浄方法。 [15] The method for cleaning equipment described in [14], in which the equipment is a filter, and the metal substances are dissolved and removed by passing the cleaning solution through the filter.
［１６］前記フィルターが有機樹脂製である、［１５］に記載の設備の洗浄方法。 [16] The method for cleaning equipment described in [15], wherein the filter is made of an organic resin.
本発明によれば、フィルター膜面に付着した硫化銀及び硫化銅などの金属物質を溶解除去し、フィルターの膜性能を回復させることができる洗浄液が提供される。 The present invention provides a cleaning solution that can dissolve and remove metal substances such as silver sulfide and copper sulfide that are attached to the filter membrane surface, and restore the membrane performance of the filter.
以下、本発明の実施の形態について詳細に説明する。なお、本明細書における「Ａ～Ｂ」という表現は、Ａ（数値）以上かつＢ（数値）以下の範囲を意味する。 The following describes in detail the embodiments of the present invention. In this specification, the expression "A to B" means a range equal to or greater than A (number) and equal to or less than B (number).
［洗浄液］
本発明の洗浄液は、乳酸、チオウレア構造を有する化合物、硫酸及び水を含有する。以下、これらの各成分について説明する。
[Cleaning solution]
The cleaning solution of the present invention contains lactic acid, a compound having a thiourea structure, sulfuric acid, and water. Each of these components will be described below.
＜乳酸＞
本発明の洗浄液の実施の形態は、乳酸を含有する。後述する通り、当該洗浄液はチオウレア構造を有する化合物により硫化銀及び硫化銅などの金属物質（における金属）を錯体化させて溶解するものと考えられる。なお本明細書において、前記金属物質とは、金属単体及び金属化合物を指すものとする。
<Lactic acid>
The embodiment of the cleaning solution of the present invention contains lactic acid. As described below, it is considered that the cleaning solution dissolves metal substances such as silver sulfide and copper sulfide (metals in the metals) by complexing them with a compound having a thiourea structure. In this specification, the metal substances refer to simple metals and metal compounds.
前記の錯体化・溶解の際に、乳酸は形成された錯体を安定化させ、イオンとなった銀や銅がカウンターイオンなどの何らかの物質と反応して再析出することを防止する機能を発揮すると考えられる。このような機能から、洗浄液中に乳酸又は乳酸イオンが存在すればよく、これらは、洗浄液の製造において、乳酸の塩（例えばナトリウム塩やカリウム塩などの金属塩）として添加され、その結果として洗浄液中において存在するものであってもよい。本明細書においては、乳酸及び乳酸イオンを総称して「乳酸」と称する。 During the above-mentioned complexation and dissolution, lactic acid is thought to stabilize the complex formed and to function to prevent the ionized silver or copper from reacting with some substance such as a counter ion and re-precipitating. Due to this function, it is sufficient for lactic acid or lactate ions to be present in the cleaning solution, and these may be added as a salt of lactic acid (e.g., a metal salt such as a sodium salt or potassium salt) during the production of the cleaning solution, and as a result, they may be present in the cleaning solution. In this specification, lactic acid and lactate ions are collectively referred to as "lactic acid".
本発明の洗浄液の実施の形態における乳酸の含有量は、本発明の効果を奏する限り特に制限されない。乳酸の効果の発揮と薬剤コストの観点から、前記含有量は１～５０質量％であることが好ましく、１．２～３０質量％であることがより好ましく、１．５～１０質量％であることが更に好ましい。 The content of lactic acid in the embodiment of the cleaning solution of the present invention is not particularly limited as long as the effects of the present invention are achieved. From the viewpoint of exerting the effects of lactic acid and the cost of the drug, the content is preferably 1 to 50 mass%, more preferably 1.2 to 30 mass%, and even more preferably 1.5 to 10 mass%.
＜チオウレア構造を有する化合物＞
本発明の洗浄液の実施の形態は、チオウレア構造を有する化合物を含有する。当該化合物は従来知られている通り、硫化銀及び硫化銅などの金属物質を錯体化させるものと考えられる。
<Compound having a thiourea structure>
An embodiment of the cleaning solution of the present invention contains a compound having a thiourea structure, which is believed to complex metal substances such as silver sulfide and copper sulfide, as is conventionally known.
チオウレア構造とは、下記で表される構造である。
チオウレア構造を有する化合物の例としては、下記一般式（１）で表される化合物が挙げられる。
式（１）において、Ｒはそれぞれ独立に、水素又は炭素数１～１２のアルキル基である。前記アルキル基は、分岐を有していてもよく、ハロゲン原子で置換されていてもよい。金属物質との反応で生成する錯体の洗浄液（特に水）中への溶解性の観点から、Ｒとしては炭素数１～４のアルキル基が好ましく、より好ましくは炭素数１～３のアルキル基である。チオウレア構造を有する化合物の具体例としては、チオ尿素が挙げられる。 In formula (1), each R is independently hydrogen or an alkyl group having 1 to 12 carbon atoms. The alkyl group may be branched and may be substituted with a halogen atom. From the viewpoint of the solubility of the complex produced by the reaction with the metal substance in a cleaning solution (particularly water), R is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. A specific example of a compound having a thiourea structure is thiourea.
本発明の洗浄液の実施の形態におけるチオウレア構造を有する化合物の含有量は、本発明の効果を奏する限り特に制限されない。錯体化効果の発揮と薬剤コストの観点から、前記含有量は１～１５質量％であることが好ましく、１．２～１０質量％であることがより好ましく、１．５～８質量％であることが更に好ましい。 The content of the compound having a thiourea structure in the embodiment of the cleaning solution of the present invention is not particularly limited as long as the effects of the present invention are achieved. From the viewpoint of exerting the complexing effect and the cost of the chemical, the content is preferably 1 to 15 mass%, more preferably 1.2 to 10 mass%, and even more preferably 1.5 to 8 mass%.
＜硫酸＞
本発明の洗浄液の実施の形態は、硫酸を含有する。硫酸の存在により洗浄液は通常酸性となり、チオウレア構造を有する化合物の錯体化能力を高めることができる。特に、硫酸により酸性とすることが、前記錯体化能力の向上に好適である。
<Sulfuric acid>
The embodiment of the cleaning solution of the present invention contains sulfuric acid. The presence of sulfuric acid usually makes the cleaning solution acidic, which can enhance the complexing ability of the compound having a thiourea structure. In particular, making the cleaning solution acidic with sulfuric acid is suitable for enhancing the complexing ability.
本発明の洗浄液の実施の形態における硫酸の含有量は、本発明の効果を奏する限り特に制限されない。チオウレア構造を有する化合物の錯体化能力を高める効果の発揮と薬剤コストの観点から、前記含有量は０．０５～１０質量％であることが好ましく、０．１～８質量％であることがより好ましく、０．３～５質量％であることが更に好ましい。 The content of sulfuric acid in the embodiment of the cleaning solution of the present invention is not particularly limited as long as the effects of the present invention are achieved. From the viewpoint of enhancing the complexing ability of the compound having a thiourea structure and of the cost of the chemical, the content is preferably 0.05 to 10% by mass, more preferably 0.1 to 8% by mass, and even more preferably 0.3 to 5% by mass.
＜水＞
本発明の洗浄液の実施の形態は、水を含有する。水は、洗浄液中のその他の物質を溶解して均一に混合する安価な媒体である。本発明の洗浄液は少量の乳酸、チオウレア構造を有する化合物及び硫酸の配合でも十分に効果を発揮し、その組成の大半（好ましくは８０質量％以上）を安価な水とすることができる。
<Water>
The embodiment of the cleaning solution of the present invention contains water. Water is an inexpensive medium that dissolves and uniformly mixes other substances in the cleaning solution. The cleaning solution of the present invention is sufficiently effective even with a small amount of lactic acid, a compound having a thiourea structure, and sulfuric acid, and the majority of the composition (preferably 80 mass% or more) can be inexpensive water.
＜その他の成分（添加剤）＞
本発明の洗浄液の実施の形態は、その他の成分として、目的に応じて各種の添加剤を含有してもよい。その添加剤の例としては、界面活性剤が挙げられる。添加剤の含有量（添加剤が複数種ある場合はその合計量）は、本発明の効果を損なわない範囲で適宜設定可能であり、好ましくは５質量％以下であり、より好ましくは３質量％以下である（洗浄液が添加剤を含む場合、その含有量は通常０．０１質量％以上である）。
<Other ingredients (additives)>
The embodiment of the cleaning solution of the present invention may contain various additives as other components depending on the purpose. Examples of the additives include surfactants. The content of the additives (the total amount of the additives when there are multiple additives) can be appropriately set within a range that does not impair the effects of the present invention, and is preferably 5% by mass or less, more preferably 3% by mass or less (when the cleaning solution contains an additive, the content is usually 0.01% by mass or more).
＜主要成分の含有量の合計＞
本発明の洗浄液は、乳酸、チオウレア構造を有する化合物、硫酸及び水を主要成分としている。これらの前記洗浄液の実施の形態における含有量の合計は、本発明の効果を奏する限り特に制限されるものではない。洗浄液の実施の形態は、主要成分以外の添加剤を含有せずとも、硫化銀などの金属物質を十分に溶解除去することができる。特に、水を除いた主要成分が上述したような比較的少量で、洗浄液の組成の大半を水としても前記の溶解除去作用が十分に発揮される。このような態様はコストの点から望ましく、このような態様において、前記主要成分の洗浄液中の含有量の合計は、好ましくは９０質量％以上であり（この場合水の含有量は好ましくは８０質量％以上である）、より好ましくは９５質量％以上であり（この場合水の含有量は好ましくは８３質量％以上である）、更に好ましくは９８質量％以上である（この場合水の含有量は好ましくは８５質量％以上である）。
<Total content of major ingredients>
The cleaning solution of the present invention is composed of lactic acid, a compound having a thiourea structure, sulfuric acid, and water as main components. The total content of these components in the embodiment of the cleaning solution is not particularly limited as long as the effect of the present invention is achieved. The embodiment of the cleaning solution can sufficiently dissolve and remove metal substances such as silver sulfide without containing additives other than the main components. In particular, even if the main components other than water are relatively small as described above and the majority of the composition of the cleaning solution is water, the dissolving and removing action is sufficiently exhibited. Such an embodiment is desirable from the viewpoint of cost, and in such an embodiment, the total content of the main components in the cleaning solution is preferably 90% by mass or more (in this case, the water content is preferably 80% by mass or more), more preferably 95% by mass or more (in this case, the water content is preferably 83% by mass or more), and even more preferably 98% by mass or more (in this case, the water content is preferably 85% by mass or more).
＜洗浄液のｐＨ＞
本発明の洗浄液の実施の形態の２５℃におけるｐＨは、チオウレア構造を有する化合物の錯体化能力を十分に発揮させるべく、酸性領域にあることが好ましく、具体的には０～５が好ましく、０．１～２であることがより好ましい。
<pH of cleaning solution>
The pH of the cleaning solution of the embodiment of the present invention at 25° C. is preferably in the acidic region, specifically, preferably 0 to 5, and more preferably 0.1 to 2, in order to fully exhibit the complexing ability of the compound having a thiourea structure.
＜洗浄液の製造方法＞
本発明の洗浄液は、以上説明した主要成分、および必要に応じてその他の成分を公知の方法で混合することにより、製造することができる。また、いずれかの成分を先に混合しておき、その混合物へ残りの成分を順次混合してもよい。各成分の使用量については、本発明の洗浄液の実施の形態について説明した、各成分の含有量、主要成分の含有量の合計となるようにすることが好ましい。
<Method of manufacturing cleaning solution>
The cleaning solution of the present invention can be produced by mixing the above-described main components and, if necessary, other components by a known method. Alternatively, one of the components may be mixed first, and the remaining components may be mixed in sequence into the mixture. The amount of each component used is preferably the sum of the contents of each component and the main components, as described in the embodiment of the cleaning solution of the present invention.
＜洗浄液の用途＞
本発明の洗浄液の実施の形態は、幅広い金属物質を錯体化させその状態を維持することができるので、各種金属物質の溶解除去の用途に好適である。特に溶解除去対象の金属物質として、銀、銀化合物、銅、銅化合物、鉄、鉄化合物、亜鉛及び亜鉛化合物が好適である。
<Uses of cleaning solution>
The cleaning solution according to the embodiment of the present invention is capable of forming a complex with a wide range of metal substances and maintaining the complex state, and is therefore suitable for use in dissolving and removing various metal substances, particularly silver, silver compounds, copper, copper compounds, iron, iron compounds, zinc, and zinc compounds.
前記銀化合物の具体例としては、硫化銀、酸化銀、ハロゲン化銀、ヘキサメチレンテトラミン銀錯体及び硫酸銀が挙げられ、本発明の洗浄液の実施の形態による除去対象としては、硫化銀が特に好ましい。 Specific examples of the silver compound include silver sulfide, silver oxide, silver halide, hexamethylenetetramine silver complex, and silver sulfate, and silver sulfide is particularly preferred as a target for removal by the cleaning solution of the present invention.
前記銅化合物の具体例としては、硫化銅、酸化銅、ヘキサメチレンテトラミン銅錯体及び亜酸化銅が挙げられ、本発明の洗浄液の実施の形態による除去対象としては、硫化銅が特に好ましい。 Specific examples of the copper compound include copper sulfide, copper oxide, hexamethylenetetramine copper complex, and cuprous oxide, and copper sulfide is particularly preferred as a target for removal by the cleaning solution of the present invention.
前記鉄化合物の具体例としては、硫化鉄及び酸化鉄が挙げられ、本発明の洗浄液の実施の形態による除去対象としては、硫化鉄が特に好ましい。 Specific examples of the iron compounds include iron sulfide and iron oxide, and iron sulfide is particularly preferred as a target for removal by the cleaning solution of the present invention.
前記亜鉛化合物の具体例としては、硫化亜鉛及び酸化亜鉛が挙げられ、本発明の洗浄液の実施の形態による除去対象としては、硫化亜鉛が特に好ましい。 Specific examples of the zinc compound include zinc sulfide and zinc oxide, and zinc sulfide is particularly preferred as a target for removal by the cleaning solution of the present invention.
本発明の洗浄液の実施の形態による溶解除去作用が好適に奏される点から、除去対象である金属物質としては、銀、銀化合物、銅及び銅化合物が好ましく、硫化銀及び硫化銅が特に好ましい。 In order to effectively achieve the dissolving and removing effect of the cleaning solution of the present invention, the metal substances to be removed are preferably silver, silver compounds, copper and copper compounds, and particularly preferably silver sulfide and copper sulfide.
以上説明した通り、本発明の洗浄液の実施の形態は、各種金属物質を好適に溶解除去することができるが、特に、前記金属物質が付着した設備を洗浄（金属物質を溶解除去）する用途に好適である。前記設備とは、前記金属物質が付着しうるものである限り特に制限はなく、例えば前記金属物質が何らかの目的で添加されうる反応装置や、金属物質を含有する液体を固液分離するフィルターが挙げられる。 As explained above, the embodiment of the cleaning solution of the present invention can suitably dissolve and remove various metal substances, but is particularly suitable for use in cleaning equipment to which the metal substances are attached (dissolving and removing the metal substances). The equipment is not particularly limited as long as it is something to which the metal substances can adhere, and examples include reaction equipment to which the metal substances can be added for some purpose, and filters that perform solid-liquid separation of liquids containing metal substances.
前記フィルターとは、液体と固体の混合液から特定のサイズの固体を除去するための装置である。フィルターは除去対象の固体のサイズ以下の大きさの孔を備えており、前記混合液をフィルターに通すことで、液体及び孔のサイズより小さい固体はそのフィルターを透過し、孔のサイズより大きい固体はフィルターを透過しない。このようにして特定サイズの固体が除去される。なおフィルターは構造が微細であり、物理的損傷も受けやすいので、本発明の洗浄液の実施の形態（液体）による洗浄が特に好適である。 The filter is a device for removing solids of a specific size from a mixture of liquid and solids. The filter has holes that are smaller than the size of the solids to be removed, and by passing the mixture through the filter, the liquid and solids smaller than the size of the holes pass through the filter, while solids larger than the size of the holes do not. In this way, solids of a specific size are removed. Since filters have a fine structure and are easily damaged physically, cleaning with the embodiment (liquid) of the cleaning liquid of the present invention is particularly suitable.
長期にわたって同じフィルターに液体と固体の混合液を通していると、フィルター上に、その孔のサイズ以上の大きさの固体（本発明でいえば、洗浄液による除去対象である金属物質）が付着し、その固体の上に更に固体が堆積していき、フィルターの詰まり（閉塞）が生じる。本発明においては、フィルターに直接付着した金属物質だけでなく、その上に堆積した金属物質も、フィルターに「付着した」ものとみなす。 If a mixture of liquids and solids is passed through the same filter for a long period of time, solids larger than the size of the pores of the filter (in this case, the metal substances to be removed by the cleaning liquid) will adhere to the filter, and further solids will accumulate on top of the solids, causing the filter to become clogged (blocked). In this invention, not only the metal substances directly attached to the filter, but also the metal substances that have accumulated on top of them are considered to be "adhered" to the filter.
フィルターには、処理対象の混合液を全量透過させる（除去対象の固体は透過しないが）デッドエンド型と、処理対象の混合液の流れの周囲に除去対象の固体のサイズ以下の大きさの孔を設けるクロスフロー型とがある。本発明の洗浄液の実施の形態は、どちらのタイプのフィルターの洗浄にも適用可能である。なお、本発明にて「フィルター」にはＲＯ膜（Reverse Osmosis Membrane）及びＮＦ膜（Nanofiltration Membrane）が包含されるものとする。 There are two types of filters: dead-end type, which allows the entire amount of the mixed liquid to be treated to pass through (but not the solids to be removed), and cross-flow type, which has holes around the flow of the mixed liquid to be treated that are smaller than the size of the solids to be removed. The embodiment of the cleaning solution of the present invention can be applied to cleaning either type of filter. In this invention, the term "filter" includes RO membranes (reverse osmosis membranes) and NF membranes (nanofiltration membranes).
なお、通常、フィルターは固液分離を目的として使用されるので、混合液から全ての固体を除去すべく、フィルターの孔のサイズは除去対象の固体の最小サイズを基準に選択されることが多い。孔のサイズは、孔が網目状に形成されている場合の目開き、空孔の場合の孔径などとして規定される。これらのサイズは、本発明の洗浄液の実施の形態の溶解除去対象である金属物質を除去対象とする場合は、好ましくは１０μｍ以下とされ、より好ましくは５μｍ以下とされる。なお、フィルターそれ自体のコストの観点から孔のサイズは好ましくは０．２μｍ以上である。 Since filters are usually used for the purpose of solid-liquid separation, the size of the filter pores is often selected based on the smallest size of the solids to be removed in order to remove all solids from the mixed liquid. The size of the pores is specified as the mesh size when the pores are formed in a mesh shape, or the pore size when the pores are empty. When metal substances, which are the subject of dissolution and removal in the embodiment of the cleaning solution of the present invention, are to be removed, these sizes are preferably 10 μm or less, and more preferably 5 μm or less. From the viewpoint of the cost of the filter itself, the size of the pores is preferably 0.2 μm or more.
フィルターには大きく分けてセラミック製のものと、ポリオレフィンなどの有機樹脂製のものとがある。コストの観点からは有機樹脂製のものが有利である。本発明の洗浄液の実施の形態は、いずれのフィルターの洗浄にも適用可能である。なお、有機樹脂は強力な酸化剤（金属物質を溶解可能である。二クロム酸カリウムなどの無機酸化剤がこれに該当する）によって分解するおそれがあるので、有機樹脂製のフィルターを洗浄する場合には、洗浄液としてそのような酸化剤を実質的に含まない組成のものを採用することが好ましい。 Filters are broadly divided into those made of ceramic and those made of organic resins such as polyolefin. From the viewpoint of cost, organic resins are advantageous. The embodiment of the cleaning liquid of the present invention can be applied to cleaning either type of filter. Note that organic resins may be decomposed by strong oxidizing agents (capable of dissolving metal substances, such as inorganic oxidizing agents such as potassium dichromate), so when cleaning organic resin filters, it is preferable to use a cleaning liquid with a composition that is substantially free of such oxidizing agents.
［設備の洗浄方法］
次に、本発明の設備の洗浄方法について説明するが、具体的な実施の形態として、前記設備がフィルターである場合を例として説明する。当該実施の形態では、上記で説明した金属物質が付着したフィルターに、本発明の洗浄液の実施の形態を接触させて、前記金属物質を溶解除去することで、フィルターを洗浄する。
[How to clean equipment]
Next, the method for cleaning equipment of the present invention will be described, taking as an example a case where the equipment is a filter as a specific embodiment. In this embodiment, the filter to which the above-described metal substances are attached is brought into contact with the embodiment of the cleaning solution of the present invention, and the metal substances are dissolved and removed, thereby cleaning the filter.
金属物質による閉塞が生じたフィルターではその透過流量が低下して、フィルターの、液体と固体の混合液の処理効率が低下してしまい、またその洗浄が困難であることから、従来はフィルターの交換が必要であった。しかし本発明の設備の洗浄方法によれば、このようなフィルターを洗浄して、その処理効率を回復させることができる。すなわち当該洗浄方法は、同一の（金属物質を含むスラリーの固液分離に利用される）フィルターの長期利用を可能とする。具体的には、本発明の設備の洗浄方法の実施の形態によれば、フィルターのろ過フラックス（単位時間・単位面積あたりに液体がフィルターを透過する量であり、詳細については後述の実施例にて説明する）を、新品のものを１００％として、好ましくは７５％以上まで回復させることができる。なお、１００％まで回復させる必要は現実的には無く、そこまで回復させようとすると洗浄液の使用量や、洗浄液をフィルターに接触させる時間が長くなって洗浄効率が下がることから、本発明の設備の洗浄方法の実施の形態は、フィルターのろ過フラックスを、新品のものを１００％として、より好ましくは８０～９８％、更に好ましくは８３～９６％まで回復させる。 In a filter clogged with metal substances, the permeation flow rate decreases, and the filter's processing efficiency of a mixture of liquid and solids decreases. In addition, cleaning the filter is difficult, so that the filter had to be replaced in the past. However, according to the equipment cleaning method of the present invention, such a filter can be cleaned and its processing efficiency restored. In other words, the cleaning method enables the same filter (used for solid-liquid separation of a slurry containing metal substances) to be used for a long period of time. Specifically, according to an embodiment of the equipment cleaning method of the present invention, the filtration flux of the filter (the amount of liquid that permeates the filter per unit time and unit area, details of which will be explained in the examples below) can be restored to preferably 75% or more, assuming that a new filter is 100%. However, it is not actually necessary to restore the filter to 100%, and if an attempt is made to restore the filter to that extent, the amount of cleaning solution used and the time that the cleaning solution is in contact with the filter will be extended, resulting in a decrease in cleaning efficiency. Therefore, in an embodiment of the equipment cleaning method of the present invention, the filtration flux of the filter is restored to more preferably 80 to 98%, and even more preferably 83 to 96%, assuming that a new filter is 100%.
金属物質が付着したフィルターに洗浄液を接触させる方法に、特に制限はない。例えば洗浄液にフィルターを浸漬したり、フィルターに洗浄液を通液させることで、フィルターを洗浄することができる。後者の形態によれば、設置されたままの状態のフィルターに対して洗浄液を通液して洗浄することができ、フィルターの取り外しなどの付加的操作が不要であるので、好ましい。 There are no particular limitations on the method of bringing the cleaning liquid into contact with the filter having metal substances attached thereto. For example, the filter can be cleaned by immersing the filter in the cleaning liquid or by passing the cleaning liquid through the filter. The latter method is preferable because it allows the filter to be cleaned while still installed by passing the cleaning liquid through it, and does not require additional operations such as removing the filter.
本発明の設備の洗浄方法の実施の形態において、洗浄液の使用量は、フィルターに付着した金属物質の全量を溶解除去できる量であれば特に制限はない。好ましい使用量は、使用される洗浄液中の乳酸及びチオウレア構造を有する化合物の量が、フィルターに付着した金属物質の量に対して２０～１０００モル倍となる量である。なおフィルターに付着した金属物質の量は、例えば、そのフィルターが設置されたプロセス設備を操業して、どの程度の期間でどの程度の量の金属物質がフィルターに付着するかといったデータを取得することにより、平均的な量として求めることができる。 In the embodiment of the equipment cleaning method of the present invention, the amount of cleaning liquid used is not particularly limited as long as it is an amount that can dissolve and remove all of the metal substances attached to the filter. A preferred amount is an amount in which the amount of lactic acid and the compound having a thiourea structure in the cleaning liquid used is 20 to 1000 times the molar amount of the metal substances attached to the filter. The amount of metal substances attached to the filter can be determined as an average amount, for example, by operating a process facility in which the filter is installed and obtaining data on the amount of metal substances that adhere to the filter over a period of time.
本発明の設備の洗浄方法の実施の形態において、洗浄液を金属物質が付着したフィルターに接触させる時間は、金属物質の汚染（付着）の程度により増減するが、好ましくは１～２０時間程度である。 In an embodiment of the equipment cleaning method of the present invention, the time for which the cleaning solution is in contact with the filter having metal substances attached thereto varies depending on the degree of contamination (attachment) of the metal substances, but is preferably about 1 to 20 hours.
なお、フィルターに付着した金属物質に関して、フィルターの処理対象である混合液が有機物も含む場合には、金属物質上に有機物がコーティング膜のように堆積している場合がある。この場合には、まず水酸化ナトリウム水溶液のようなアルカリ水溶液をフィルターに接触させて前記有機物を除去して（脱脂）、その後に洗浄液による洗浄を実施することが好ましい。 Regarding the metal substances adhering to the filter, if the mixed liquid to be treated by the filter also contains organic matter, the organic matter may accumulate on the metal substances like a coating film. In this case, it is preferable to first bring an alkaline aqueous solution such as an aqueous sodium hydroxide solution into contact with the filter to remove the organic matter (degreasing), and then wash the filter with a cleaning solution.
本発明の設備の洗浄方法の実施の形態により金属物質が付着したフィルターを洗浄した後は、フィルター上に残留した本発明の洗浄液の実施の形態を水で洗い流すことが好ましい。 After cleaning the filter to which metal substances have adhered using the embodiment of the equipment cleaning method of the present invention, it is preferable to rinse away any remaining cleaning solution of the present invention on the filter with water.
以下、実施例及び比較例により本発明を更に詳細に説明するが、本発明はこれらに限定されない。 The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these.
［１．洗浄液組成の検討］
下記表１の組成の各洗浄液を、各成分を混合することで調製した。
Each cleaning solution having the composition shown in Table 1 below was prepared by mixing the respective components.
洗浄性能を評価するための試料（洗浄対象）はＡｇ２Ｓ／ＣｕＳ混合物（粉末）である。Ａｇ２ＳとＣｕＳの混合割合（質量比）は、約４：６である。前記試料１０ｍｇを５つの試験管にとり、これに各洗浄液２０ｍＬを注いだ。試料と洗浄液が入った各試験管を振盪装置にセットし、室温下、２００ｒｐｍで６時間振盪した。 The sample (cleaning target) for evaluating the cleaning performance was a Ag 2 S/CuS mixture (powder). The mixture ratio (mass ratio) of Ag 2 S and CuS was about 4:6. 10 mg of the sample was placed in five test tubes, and 20 mL of each cleaning solution was poured into them. Each test tube containing the sample and cleaning solution was placed in a shaking device and shaken at room temperature at 200 rpm for 6 hours.
振盪後の各試験管を観察し、試料（粉末）の溶解状態を観察した。なお実施例１については、非常に溶解速度が高く、２時間の振盪をした時点で一度状態を観察したところ、粉末が試験管内に見えない状態となっていた。試料はこの時点で完全に溶解したと考えられる。一方比較例１～３については（６時間の振盪後において）残渣があり、溶解は起こらなかったと考えられる。比較例４については残渣の量が少なかったので、試料が一部溶解したものと考えられる。 After shaking, each test tube was observed to see how the sample (powder) had dissolved. Note that in Example 1, the dissolution rate was extremely high, and when the condition was observed once after 2 hours of shaking, the powder was no longer visible in the test tube. It is believed that the sample had completely dissolved at this point. On the other hand, in Comparative Examples 1 to 3, residue was found (after 6 hours of shaking), and it is believed that no dissolution had occurred. In Comparative Example 4, the amount of residue was small, so it is believed that the sample had only partially dissolved.
なお、試料中のＣｕＳの量は０．０４ｍｍｏｌ、Ａｇ２Ｓの量は０．０２ｍｍｏｌであり、これに対して実施例１の洗浄液中の乳酸は１１ｍｍｏｌ、チオ尿素は１３ｍｍｏｌ、硫酸は２ｍｍｏｌであった。 The amount of CuS in the sample was 0.04 mmol, and the amount of Ag 2 S was 0.02 mmol, whereas the cleaning solution in Example 1 contained 11 mmol of lactic acid, 13 mmol of thiourea, and 2 mmol of sulfuric acid.
［２．デッドエンド型フィルターの洗浄性能の評価］
（１）目詰まりフィルターの作製
試験に供するフィルターとしては、目開き０．４５μｍのメンブランフィルター（ニトロセルロース製）を使用した。これの膜面積は，９．０７ｃｍ２である。
[2. Evaluation of cleaning performance of dead-end type filter]
(1) Preparation of clogged filter A membrane filter (made of nitrocellulose) with a mesh size of 0.45 μm and a membrane area of 9.07 cm2 was used for the test.
フィルターに目詰まりを生じさせる試験液を以下のようにして調製した。１．０ｇの寺田薬泉製ＣｕＳを水１００ｇにリパルプし、ＡｇＮＯ３を０．５ｇ添加した。銀と銅の置換反応後（Ａｇ２Ｓが生成）、固形物を超音波分散し、粒子を微細化した。 A test solution for causing clogging of the filter was prepared as follows: 1.0 g of CuS manufactured by Terada Yakusen was repulped in 100 g of water, and 0.5 g of AgNO3 was added. After the substitution reaction of silver with copper ( Ag2S was produced), the solid matter was ultrasonically dispersed to reduce the particle size.
このようにして調製した試験液を上記メンブランフィルターで減圧濾過した。次に、フィルター上のケーキを回収し、このケーキについて再度水によるリパルプ及び超音波分散と前記フィルターでの減圧ろ過を行った。このケーキ回収～減圧ろ過の操作を１０回繰り返し、目詰まりフィルターを得た。 The test solution thus prepared was filtered under reduced pressure through the membrane filter. The cake on the filter was then collected, and this cake was repulped with water, ultrasonically dispersed, and filtered under reduced pressure through the filter. This process of cake collection and reduced pressure filtration was repeated 10 times to obtain a clogged filter.
（２）目詰まりフィルターのろ過フラックスの測定
上記（１）で作製した目詰まりフィルターを減圧濾過器にセットし、上記（１）で得られた試験液のろ液２５０ｍＬをろ過し（室温（２６℃））、ろ過に要した時間と、フィルター面積（９．０７ｃｍ２）と、ろ液量（２５０ｍＬ）からろ過フラックスを求めた。ろ過フラックスは、単位面積・単位時間あたりの透過液の量であり、「Ｌ／ｍ２／ｈｒ」の次元で表現され、Ｌはｍ３に換算できることから、「ｍ／ｈｒ」の次元でも表現できる。
(2) Measurement of filtration flux of clogged filter The clogged filter prepared in (1) above was set in a vacuum filter, and 250 mL of the filtrate of the test liquid obtained in (1) above was filtered (room temperature (26°C)), and the filtration flux was calculated from the time required for filtration, the filter area (9.07 cm2 ), and the amount of filtrate (250 mL). Filtration flux is the amount of permeated liquid per unit area and unit time, and is expressed in terms of "L/ m2 /hr", and since L can be converted to m3 , it can also be expressed in terms of "m/hr".
（３）目詰まりフィルターの洗浄とろ過フラックスの回復確認
上記（２）の試験に供した目詰まりフィルターに実施例１の洗浄液を１００ｍＬ注ぎ、フィルターが洗浄液中に存在する状態で４時間静置した後に洗浄液を除去した。その後、上記（２）の試験と同様な方法で、洗浄後フィルターのろ過フラックスを測定した。また、新品のメンブランフィルターについても同様な方法でろ過フラックスを測定した。
(3) Cleaning of clogged filter and confirmation of recovery of filtration flux 100 mL of the cleaning solution of Example 1 was poured onto the clogged filter used in the test in (2) above, and the filter was left to stand in the cleaning solution for 4 hours, after which the cleaning solution was removed. Thereafter, the filtration flux of the cleaned filter was measured in the same manner as in the test in (2) above. The filtration flux of a new membrane filter was also measured in the same manner.
以上の結果を下記表２に示す。洗浄により、フィルターのろ過フラックスは新品のものの約８８％にまで回復していた。
［３．クロスフロー式ろ過フィルターの洗浄性能の評価］
特許文献２に開示されるプロセス、具体的には銀を含有する被処理液に硫化銅を添加して、クロスフロー型のフィルター（ポリプロピレン製中空糸膜モジュール）により固液分離して銀を回収するプロセスを長期操業した。その結果、中空糸膜モジュールが硫化銀および硫化銅の混合物で目詰まりし、これに対して実施例１の洗浄液による洗浄を実施した。
[3. Evaluation of cleaning performance of cross-flow filter]
The process disclosed in Patent Document 2, specifically, a process in which copper sulfide is added to a silver-containing liquid to be treated and silver is recovered by solid-liquid separation using a cross-flow filter (a polypropylene hollow fiber membrane module), was operated for a long period of time. As a result, the hollow fiber membrane module became clogged with a mixture of silver sulfide and copper sulfide, and cleaning with the cleaning solution of Example 1 was carried out.
具体的には、中空糸膜が装填された膜モジュール外に透過液が出ないようにモジュールのバルブを閉めて，膜モジュールに洗浄液を循環させた。循環時間は６時間とした。その後、膜モジュール内の洗浄液を排出し、逆洗浄水で膜モジュールを洗浄した。 Specifically, the valve of the membrane module loaded with hollow fiber membranes was closed to prevent the permeate from leaking out, and the cleaning solution was circulated through the membrane module. The circulation time was set to 6 hours. After that, the cleaning solution in the membrane module was discharged, and the membrane module was washed with backwash water.
洗浄前と洗浄後の、膜モジュール断面の走査電子顕微鏡（ＳＥＭ）写真を図１に示す（左側が洗浄前、右側が洗浄後の写真）。なお、洗浄前と洗浄後それぞれのＳＥＭの試料として、異なる膜モジュール由来のものを用いている。洗浄前のＳＥＭ写真では、中空糸膜と空気の境界面に高比重物質（白く見えているもの）が確認された。洗浄後のＳＥＭ写真においては、前記高比重物質は確認されなかった。 Scanning electron microscope (SEM) photographs of the cross section of the membrane module before and after cleaning are shown in Figure 1 (the photograph on the left is before cleaning, and the photograph on the right is after cleaning). Note that the SEM samples taken before and after cleaning were taken from different membrane modules. In the SEM photograph before cleaning, a high-density substance (appearing white) was confirmed at the interface between the hollow fiber membrane and the air. In the SEM photograph after cleaning, the high-density substance was not confirmed.
新品及び洗浄前後の膜モジュールの膜透過性能を評価するため、それぞれのろ過フラックスを測定した。ろ過フラックス測定には、硫化銀と硫化銅の混合物を含むスラリー（試験液）を用いた（硫化銀と硫化銅合計での濃度は４ｇ／Ｌ）。試験液を循環流速０．１５ｍ／ｍｉｎで膜モジュールを循環させた。循環流速は、膜モジュールの膜面積（ｍ２）に対する，循環液量（Ｌ／ｍｉｎ）である。本試験の場合、中空糸膜モジュールへの循環液の圧入圧力を０．０６ＭＰａとすることで、前記の循環流速となった。試験液を循環させた時間と、透過液量と、膜モジュールの面積とから、ろ過フラックスを求めた。結果を以下の表３に示す。 In order to evaluate the membrane permeation performance of the new membrane module and the membrane module before and after cleaning, the filtration flux of each was measured. For the filtration flux measurement, a slurry (test liquid) containing a mixture of silver sulfide and copper sulfide was used (the total concentration of silver sulfide and copper sulfide was 4 g/L). The test liquid was circulated through the membrane module at a circulation flow rate of 0.15 m/min. The circulation flow rate is the amount of circulating liquid (L/min) relative to the membrane area (m 2 ) of the membrane module. In this test, the above circulation flow rate was achieved by setting the pressure of the circulating liquid into the hollow fiber membrane module to 0.06 MPa. The filtration flux was calculated from the time the test liquid was circulated, the amount of permeated liquid, and the area of the membrane module. The results are shown in Table 3 below.
洗浄により、中空糸膜モジュールのろ過フラックスは新品のものの９０％にまで回復していた。そして、洗浄後の中空糸膜モジュールは、洗浄前と同様に硫化銀および硫化銅の混合物をキャッチすることができた（洗浄によるフィルター機能の低下は認められなかった）。
The cleaning restored the filtration flux of the hollow fiber membrane module to 90% of that of a new module, and the hollow fiber membrane module after cleaning was able to capture a mixture of silver sulfide and copper sulfide in the same way as before cleaning (no deterioration in filter function due to cleaning was observed).
Claims (6)
前記洗浄液中の、前記乳酸の含有量が１～５０質量％、前記チオ尿素の含有量が１～１５質量％、前記硫酸の含有量が０．０５～１０質量％となる割合で、前記乳酸、チオ尿素、硫酸及び水を混合する、洗浄液の製造方法。 A method for producing a cleaning solution used for cleaning a filter having at least one metal substance selected from the group consisting of silver sulfide and copper sulfide attached thereto , the method comprising the steps of mixing lactic acid, thiourea , sulfuric acid, and water,
The method for producing a cleaning solution includes mixing the lactic acid, thiourea, sulfuric acid, and water in such proportions that the content of the lactic acid in the cleaning solution is 1 to 50 mass%, the content of the thiourea is 1 to 15 mass%, and the content of the sulfuric acid is 0.05 to 10 mass%.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002301496A (en) | 2001-02-05 | 2002-10-15 | Otsuka Chem Co Ltd | Scale removing and preventing agent |
| JP2003027096A (en) | 2001-07-13 | 2003-01-29 | Niitaka:Kk | Aqueous detergent for silverware |
| JP2007270222A (en) | 2006-03-30 | 2007-10-18 | Kurita Water Ind Ltd | Scale detergent and scale removing method |
| JP2015105412A (en) | 2013-11-29 | 2015-06-08 | 三菱重工業株式会社 | Dissolving and removing composition |
| WO2016129352A1 (en) | 2015-02-12 | 2016-08-18 | メック株式会社 | Etching liquid and etching method |
| JP2017203087A (en) | 2016-05-10 | 2017-11-16 | ユシロ化学工業株式会社 | Rust remover composition |
| JP2019063710A (en) | 2017-09-29 | 2019-04-25 | Ｄｏｗａテクノロジー株式会社 | Treatment method and treatment apparatus of liquid to be treated |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3065280B2 (en) * | 1997-07-30 | 2000-07-17 | 日本表面化学株式会社 | Descaled pickling solution for steel and method for descaled pickling |
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Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002301496A (en) | 2001-02-05 | 2002-10-15 | Otsuka Chem Co Ltd | Scale removing and preventing agent |
| JP2003027096A (en) | 2001-07-13 | 2003-01-29 | Niitaka:Kk | Aqueous detergent for silverware |
| JP2007270222A (en) | 2006-03-30 | 2007-10-18 | Kurita Water Ind Ltd | Scale detergent and scale removing method |
| JP2015105412A (en) | 2013-11-29 | 2015-06-08 | 三菱重工業株式会社 | Dissolving and removing composition |
| WO2016129352A1 (en) | 2015-02-12 | 2016-08-18 | メック株式会社 | Etching liquid and etching method |
| JP2017203087A (en) | 2016-05-10 | 2017-11-16 | ユシロ化学工業株式会社 | Rust remover composition |
| JP2019063710A (en) | 2017-09-29 | 2019-04-25 | Ｄｏｗａテクノロジー株式会社 | Treatment method and treatment apparatus of liquid to be treated |
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