WO2012121270A1 - Appareil permettant l'électrolyse de l'acide sulfurique et procédé permettant l'électrolyse de l'acide sulfurique - Google Patents

Appareil permettant l'électrolyse de l'acide sulfurique et procédé permettant l'électrolyse de l'acide sulfurique Download PDF

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WO2012121270A1
WO2012121270A1 PCT/JP2012/055754 JP2012055754W WO2012121270A1 WO 2012121270 A1 WO2012121270 A1 WO 2012121270A1 JP 2012055754 W JP2012055754 W JP 2012055754W WO 2012121270 A1 WO2012121270 A1 WO 2012121270A1
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sulfuric acid
anode
cathode
electrolysis
loop
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PCT/JP2012/055754
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English (en)
Japanese (ja)
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宏紀 土門
藤井　宏治
小坂　純子
加藤　昌明
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クロリンエンジニアズ株式会社
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Priority to US14/001,636 priority Critical patent/US20130334059A1/en
Priority to CN201280022515.0A priority patent/CN103518007A/zh
Priority to KR1020137026473A priority patent/KR101551049B1/ko
Priority to JP2013503565A priority patent/JP5997130B2/ja
Publication of WO2012121270A1 publication Critical patent/WO2012121270A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/28—Per-compounds
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/22—Inorganic acids
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/042—Electrodes formed of a single material
    • C25B11/043—Carbon, e.g. diamond or graphene
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B15/00—Operating or servicing cells
    • C25B15/02—Process control or regulation
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B15/00—Operating or servicing cells
    • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes

Definitions

  • the present invention relates to a sulfuric acid electrolysis apparatus and a sulfuric acid electrolysis method for producing electrolytic sulfuric acid containing a large amount of an oxidizing substance by electrolyzing sulfuric acid. Specifically, by producing diluted sulfuric acid whose temperature and concentration are controlled in a sulfuric acid electrolysis apparatus, and further electrolyzing the diluted sulfuric acid whose temperature and concentration are controlled, it is highly efficient and safe to oxidize.
  • the present invention relates to a sulfuric acid electrolysis apparatus and a sulfuric acid electrolysis method for producing electrolytic sulfuric acid containing a substance.
  • Persulfuric acid is used as a chemical used in the process.
  • This persulfuric acid is called an “oxidizing substance” and is known to be produced by electrolysis of sulfuric acid, and has already been electrolytically produced on an industrial scale.
  • oxidizing substance refers to persulfuric acid such as peroxodisulfuric acid and peroxomonosulfuric acid, and hydrogen peroxide
  • electrolytic sulfuric acid refers to those produced by electrolyzing sulfuric acid. It contains an oxidizing substance and unreacted sulfuric acid.
  • Electrolytic sulfuric acid (hereinafter simply referred to as “electrolytic sulfuric acid”) containing an oxidizing substance and unreacted sulfuric acid generated by an apparatus for electrolyzing sulfuric acid is used in the semiconductor manufacturing process for resists, contaminated organic substances, contaminated metals, etc. Used for removal.
  • electrolytic sulfuric acid it is known that the higher the concentration of the oxidizing substance, the higher the removal effect, and the sulfuric acid electrolysis apparatus can generate electrolytic sulfuric acid containing the oxidizing substance at a higher concentration. It is required that the generation efficiency of the oxidizing substance by electrolysis is higher and the decomposability of the generated oxidizing substance is low.
  • sulfuric acid electrolysis in order to produce electrolytic sulfuric acid containing an oxidizing substance at a high concentration, to further increase the efficiency of producing the oxidizing substance by electrolysis and to lower the decomposability of the oxidizing substance, to the sulfuric acid electrolysis apparatus, It is required to supply a low concentration of sulfuric acid adjusted to a desired concentration.
  • sulfuric acid is generally sold as concentrated sulfuric acid of 98% or 96%
  • diluted sulfuric acid also referred to as diluted sulfuric acid
  • factory It is necessary to construct a new dedicated storage tank and supply pipe in the chemical supply facility, and in this case, a large amount of equipment cost is required.
  • low-concentration sulfuric acid has a larger volume than concentrated sulfuric acid, there is a problem that the cost of transporting chemicals increases compared to transporting concentrated sulfuric acid.
  • the sulfuric acid concentration can be adjusted efficiently in the sulfuric acid electrolyzer, the low cost sulfuric acid can be electrolyzed and oxidized with high efficiency while minimizing the cost of preparing dilute sulfuric acid such as equipment costs and transportation costs. Sulfuric acid electrolysis to produce a substance is possible. If the equipment and lines that make up the mechanism for generating diluted sulfuric acid from concentrated sulfuric acid and the mechanism for generating electrolytic sulfuric acid containing oxidizing substances from diluted sulfuric acid can be shared as much as possible, the sulfuric acid electrolysis apparatus can be made smaller and simpler. Can be achieved.
  • Patent Document 1 which describes the production of persulfuric acid by electrolyzing sulfuric acid in an electrolysis tank, “the concentration range of sulfuric acid used for persulfuric acid production is 2 to 11 mol / L. It is described that the production efficiency of persulfuric acid can be improved by using low-concentration sulfuric acid ”.
  • Patent Document 3 “a method of efficiently and stably producing an oxidizing substance while increasing the current efficiency for producing electrolytic sulfuric acid by using sulfuric acid having different concentrations as an electrolytic solution. Is described.
  • Patent Document 4 discloses that a gas-liquid separation means is used as a method for removing sulfuric acid contained in an electrolytic gas generated from an electrolytic reaction apparatus.
  • a gas-liquid separation means is used as a method for removing sulfuric acid contained in an electrolytic gas generated from an electrolytic reaction apparatus.
  • the removal of steam and mist generated during sulfuric acid concentration adjustment despite the fact that the sulfuric acid generated by adjusting the sulfuric acid concentration in the apparatus and sulfuric acid by mist are larger than sulfuric acid contained in the electrolytic gas.
  • the sulfuric acid concentration adjustment method is no disclosure regarding the sulfuric acid concentration adjustment method.
  • Patent Document 5 there is a description of a method of re-concentrating sulfuric acid used for washing and then diluting and cooling to re-electrolyze to produce persulfuric acid.
  • the sulfuric acid used for washing supplied at a low concentration is used. Because it is concentrated, cleanliness is different and it has safety issues.
  • the present invention removes the heat of dilution that occurs when diluting concentrated sulfuric acid into low-concentration sulfuric acid and the heat that is generated during electrolysis, and prepares electrolytic conditions that can generate an oxidizing substance with high efficiency, resulting from the heat of dilution. Suppresses the generation of mist and vapor, and also removes condensed droplets such as sulfuric acid caused by mist and vapor mixed in the exhaust system from the exhaust system, and more efficiently electrolytically generates oxidizing substances,
  • An object of the present invention is to provide a sulfuric acid electrolysis apparatus and a sulfuric acid electrolysis method that operate safely and stably.
  • the present invention is a sulfuric acid electrolysis apparatus 1 having an anode-side electrolysis unit 20 and a cathode-side electrolysis unit 23.
  • At least the anode-side electrolysis unit 20 includes concentrated sulfuric acid as a feedstock. And diluting the diluted diluted sulfuric acid to a desired temperature and concentration, and anode diluted sulfuric acid production loop A, electrolyzing the diluted sulfuric acid produced in the diluted sulfuric acid production loop A to produce electrolytic sulfuric acid, and And an anode-side electrolytic sulfuric acid production loop B for adjusting the generated electrolytic sulfuric acid to a desired temperature and concentration.
  • the anode-side diluted sulfuric acid production loop A includes an anode-side tank 31 and an anode-side concentrated sulfuric acid supply unit. 32 and the anode side cooler 34 are arranged in this order, and these are connected by the anode side bypass pipe 36 to form a loop, and further, pure water flowing into the loop A is provided at any point in the loop A.
  • An anode-side pure water supply pipe 10 is connected, and further, an anode-side concentrated sulfuric acid supply pipe 27 is connected to enable the supply of concentrated sulfuric acid to the anode-side concentrated sulfuric acid supply section 32, and the anode side
  • the electrolytic sulfuric acid production loop B includes an anode chamber 4 in which the anode 3 is provided in the electrolytic cell 2 including the anode tank 31 and the anode chamber 4 and the cathode chamber 7 formed by the diaphragm 5.
  • Concentrated sulfuric acid supplied from the anode side concentrated sulfuric acid supply pipe 27 to the anode side concentrated sulfuric acid supply unit 32 is supplied from the anode side pure water supply pipe 10 through the anode side circulation pipe 37 to form a loop.
  • the diluted low-concentration sulfuric acid is adjusted to a desired temperature and concentration while circulating in the loop A, and diluted sulfuric acid adjusted to the desired temperature and concentration is produced.
  • Produced dilute sulfuric acid the anode B is supplied to the anode chamber 4 of the electrolytic cell 2 through the anode-side circulation pipe 37 constituting the loop B, and electrolytic sulfuric acid is generated in the anode chamber 4, and the generated electrolytic sulfuric acid is supplied to the loop.
  • a sulfuric acid electrolysis apparatus characterized in that electrolytic sulfuric acid adjusted to a desired temperature and concentration is produced while being circulated in B, and adjusted to a desired temperature and concentration.
  • the second solving means according to the present invention further comprises diluting concentrated sulfuric acid as a feedstock into a low concentration sulfuric acid in the apparatus of the cathode side electrolysis unit 23, and the low concentration sulfuric acid is desired.
  • a cathode-side diluted sulfuric acid production loop A ′ that adjusts the temperature and concentration of the solution, and a cathode-side electrolytic loop B ′ that circulates the diluted sulfuric acid produced in the diluted sulfuric acid production loop A ′ through the cathode chamber 7 for circulation.
  • the cathode side diluted sulfuric acid production loop A ′ is provided with a cathode side tank 38, a cathode side concentrated sulfuric acid supply unit 39, and a cathode side cooler 41 arranged in this order, and these are connected by a cathode side bypass pipe 43. Further, a cathode-side pure water supply pipe 12 that enables the supply of pure water into the loop A ′ is connected to any part of the loop A ′.
  • Concentrated sulfuric acid can be supplied to the sulfuric acid supply unit 39
  • a concentrated sulfuric acid supply pipe 29 is connected to the cathode side electrolysis loop B ′, and the cathode side electrolysis loop B ′ is composed of the cathode side tank 38 and the anode chamber 4 and the cathode chamber 7 formed by the diaphragm 5.
  • the cathode chamber 7 in which the cathode 6 is provided is connected to the cathode side circulation pipe 44 to form a loop, and is supplied from the cathode side concentrated sulfuric acid supply pipe 29 to the cathode side concentrated sulfuric acid supply unit 39.
  • Concentrated sulfuric acid is diluted with pure water supplied from the cathode-side pure water supply pipe 12, and the diluted low-concentration sulfuric acid is adjusted to a desired temperature and concentration while circulating in the loop A ′.
  • the diluted sulfuric acid adjusted to the temperature and the concentration is generated, and the generated diluted sulfuric acid is supplied to the cathode chamber 4 of the electrolytic cell 2 through the cathode-side circulation pipe 44 constituting the loop B ′. While circulating in loop B ' And to provide the sulfate electrolysis apparatus electrolytic concentration adjusted diluted sulfuric acid is performed.
  • the third solution according to the present invention is such that the anode side gas-liquid separation mechanism 91 and the anode side mist separator 92 are sequentially connected in series to the upper part of the anode side tank 31 via the anode gas vent pipe 102.
  • the anode-side gas-liquid separation mechanism 91 and the anode-side mist separator 92 for draining the liquid accumulated in the anode-side gas-liquid separation mechanism 91 and the anode-side mist separator 92 respectively.
  • a sulfuric acid electrolysis apparatus provided with a drainage means having a structure communicating with each other.
  • the fourth solution according to the present invention is such that the anode side gas-liquid separation mechanism 91 and the anode side mist separator 92 are sequentially connected in series to the upper part of the anode side tank 31 via the anode gas vent pipe 102.
  • the anode side gas / liquid separation mechanism 91 and the anode side mist separator 92 and the anode side mist separator 92 for discharging the liquid accumulated therein are disposed at the bottoms of the anode side gas / liquid separation mechanism 91 and the anode side mist separator 92, respectively.
  • cathode side gas-liquid separation mechanism 96 and a cathode side mist separator 97 are sequentially communicated in series via a cathode gas vent pipe 103 above the cathode side tank 38.
  • a cathode gas vent pipe 103 above the cathode side tank 38.
  • Is for draining liquid was to provide a sulfuric acid electrolytic device including a drainage unit having a structure in which communication between the cathode-side gas-liquid separation mechanism 96 and a cathode side mist separator 97.
  • the fifth solving means according to the present invention is to provide a sulfuric acid electrolysis apparatus in which an ozonolysis mechanism 93 is connected to the anode side mist separator 92.
  • the sixth solving means according to the present invention is to provide a sulfuric acid electrolysis apparatus in which a hydrogen treatment mechanism is connected to the cathode side mist separator 97.
  • a seventh solution of the present invention in the diluted sulfuric acid production loop A, a plurality of the anode side tanks are provided in parallel, and the electrolytic sulfuric acid containing the generated oxidizing substance is provided in one of the anode side tanks. It is to provide a sulfuric acid electrolysis apparatus configured to generate electrolytic sulfuric acid containing an oxidizing substance having a predetermined concentration in another anode side tank after switching the valve.
  • the eighth solution of the present invention while the electrolytic sulfuric acid containing a predetermined concentration of the oxidizing substance stored in one anode side tank is sent to the use point outside the sulfuric acid electrolysis apparatus, another anode side is provided. It is an object of the present invention to provide a sulfuric acid electrolysis apparatus configured to generate electrolytic sulfuric acid containing an oxidizing substance having a predetermined concentration using a tank.
  • the ninth solution according to the present invention is to provide a sulfuric acid electrolysis device in which the anode 3 is a conductive diamond electrode.
  • a tenth solution means is to provide a sulfuric acid electrolysis apparatus in which the diaphragm 5 is a fluororesin cation exchange membrane or a porous fluororesin membrane subjected to a hydrophilic treatment.
  • an eleventh solution means provides a sulfuric acid electrolysis method characterized by producing electrolytic sulfuric acid adjusted to a desired temperature and concentration using any of the above sulfuric acid electrolysis apparatuses.
  • a twelfth solution according to the present invention uses any one of the above-described sulfuric acid electrolysis apparatuses, uses a porous fluorine-based resin film as the diaphragm 5, and a cation passes through the porous fluorine-based resin film.
  • the amount of dilute sulfuric acid solution circulating in the cathode side electrolysis loop B ′ of the cathode electrolysis unit 23 increases due to the entrained water that is entrained, the liquid level of the cathode side tank 38 is periodically or predetermined.
  • a sulfuric acid electrolysis method characterized by preventing overflow of the cathode side tank by draining a predetermined amount when reaching a height.
  • a thirteenth solution according to the present invention uses any one of the above-described sulfuric acid electrolysis apparatuses, uses a porous fluorine-based resin film as the diaphragm 5, and a cation passes through the porous fluorine-based resin film.
  • a sulfuric acid concentration of the diluted sulfuric acid solution generated in the loop A ′ of the cathode electrolysis unit 23 is lowered to a predetermined concentration or less due to the entrained water that is entrained, concentrated sulfuric acid is added to the cathode side concentrated sulfuric acid supply unit 39.
  • a sulfuric acid electrolysis method characterized by maintaining a dilute sulfuric acid concentration within a certain range by replenishing.
  • the temperature of the diluted sulfuric acid before electrolysis is increased. It is to provide any one of the above sulfuric acid electrolysis methods for adjusting the temperature so as to be 30 ° C. or lower.
  • the fifteenth solution according to the present invention is that the temperature of the electrolytic solution electrolyzed in the electrolytic sulfuric acid production loop B in the anode side electrolysis unit 20 or the cathode side electrolysis loop B ′ in the cathode side electrolysis unit 23 is 30. It is to provide any one of the above-described sulfuric acid electrolysis methods so that the temperature is adjusted to below °C.
  • the sixteenth solution according to the present invention provides a sulfuric acid concentration of diluted sulfuric acid before electrolysis in the diluted sulfuric acid production loop A in the anode side electrolysis unit 20 or the diluted sulfuric acid production loop A ′ in the cathode side electrolysis unit 23.
  • diluted sulfuric acid controlled to a desired predetermined temperature and concentration is generated in the sulfuric acid electrolysis apparatus, and the diluted sulfuric acid is further subjected to temperature controlled conditions.
  • Electrolytic sulfuric acid containing a large amount of an oxidizing substance can be generated efficiently and safely by making the electrolysis possible, and an electrolytic solution containing the oxidizing substance at a high concentration that could not be achieved by the prior art Can be manufactured with high current efficiency.
  • FIG. 1 is an overall view showing an example of a sulfuric acid electrolysis device of the present invention. It is process drawing explaining each process of the temperature and density
  • FIG. 1 is a diagram showing an example of the sulfuric acid electrolysis apparatus 1 of the present invention.
  • the sulfuric acid electrolysis apparatus 1 has an anode side electrolysis unit 20 and a cathode side electrolysis unit 23, and 2 is an electrolytic cell.
  • the electrolytic cell 2 is divided into an anode chamber 4 and a cathode chamber 7 by a diaphragm 5, an anode 3 is provided in the anode chamber 4, and a cathode 6 is provided in the cathode chamber 7.
  • the anode chamber 4 is provided in the anode side electrolysis part 20 of the sulfuric acid electrolysis apparatus 1, the present invention is characterized in that the anode side electrolysis part 20 is configured as follows.
  • the anode side electrolysis unit 20 is formed with an anode side diluted sulfuric acid production loop A and an anode side electrolytic sulfuric acid production loop B.
  • the anode side diluted sulfuric acid production loop A includes an anode side tank 31, an anode side concentrated sulfuric acid supply unit 32, an anode side circulation pump 33, and an anode side cooler 34 arranged in this order. These are connected by the anode-side bypass pipe 36 to form a loop.
  • the circulation of the liquid in the loop A can be interrupted by the anode side bypass valve 35 disposed between the anode side cooler 34 and the anode side tank 31.
  • the anode-side pure water supply pipe 10 is connected to the anode-side tank 31, and the anode-side concentrated sulfuric acid supply pipe 27 is connected to the anode-side concentrated sulfuric acid supply unit 32.
  • the concentrated sulfuric acid supplied from the anode side concentrated sulfuric acid supply pipe 27 to the anode side concentrated sulfuric acid supply part 32 through the anode side concentrated sulfuric acid supply valve 28 is supplied from the anode side pure water supply pipe 10 to the anode side in the anode side tank 31.
  • the sulfuric acid is diluted with pure water supplied through the pure water supply valve 11 to obtain low-concentration sulfuric acid.
  • the diluted sulfuric acid is adjusted to the desired temperature and concentration while circulating in Loop A.
  • the diluted sulfuric acid adjusted to a desired temperature and concentration generated in the anode side diluted sulfuric acid production loop A is supplied to the anode chamber 4 of the electrolytic cell 2 constituting the anode side electrolytic sulfuric acid production loop B and electrolyzed.
  • the anode side electrolytic sulfuric acid production loop B will be described later.
  • the pure water supplied into the anode side tank 31 is quantified by using an unillustrated integrated flow meter or a liquid level gauge provided in the tank and supplied to the anode side tank 31.
  • an ultrasonic type, an electromagnetic type, a Coriolis type, or the like can be used, and the control device controls the supply or stoppage of pure water based on the measured value or signal from the integrating flow meter or the liquid level sensor.
  • the connection part of the anode side pure water supply piping 10 is not limited to the illustration of FIG. 1, if it is in the loop A, the installation location may be anywhere. 21 is an anode chamber inlet valve, and 22 is an anode chamber outlet valve.
  • diluted sulfuric acid can be used as diluted sulfuric acid production loop A or electrolytic sulfuric acid production loop B.
  • Reference numeral 24 is a cathode chamber inlet valve
  • 25 is a cathode chamber outlet valve.
  • the anode side electrolytic sulfuric acid production loop B is a valve arranged in the middle of each pipe, in which the anode chamber 4 of the electrolytic cell 2 and the anode side tank 31 are connected by an anode side circulation pipe 37 to form a loop.
  • the dilute sulfuric acid produced in the anode-side diluted sulfuric acid production loop A can be circulated through the anode-side electrolytic sulfuric acid production loop B.
  • electrolysis of diluted sulfuric acid whose temperature and concentration were adjusted in the loop A was performed to generate electrolytic sulfuric acid, and the electrolytic sulfuric acid generated while circulating the loop B was adjusted in the loop A.
  • Diluted sulfuric acid is mixed and the electrolytic sulfuric acid is adjusted to the desired temperature and concentration.
  • fluororesin such as polytetrafluoroethylene (PTFE) or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), quartz, or the like can be used.
  • PTFE polytetrafluoroethylene
  • PFA perfluoroalkyl vinyl ether copolymer
  • Reference numeral 23 in FIG. 1 denotes a cathode side electrolysis unit of the sulfuric acid electrolysis apparatus 1.
  • a cathode side diluted sulfuric acid production loop A ′ for adjusting concentrated sulfuric acid to diluted sulfuric acid at a desired temperature and concentration, and the loop A ′ were adjusted.
  • a cathode side electrolysis loop B ′ for circulating diluted sulfuric acid through the cathode chamber 7 is formed.
  • the loop A ′ includes the cathode side tank 38, the cathode side concentrated sulfuric acid supply unit 39, the cathode side circulation pump 40, the cathode side cooler 41, the cathode side bypass valve 42, and the cathode side bypass pipe 43. And a valve disposed in the middle of each pipe.
  • the cathode-side pure water supply pipe 12 is connected to the cathode-side tank 38, and the cathode-side concentrated sulfuric acid supply pipe 29 is connected to the cathode-side concentrated sulfuric acid supply unit 39.
  • the concentrated sulfuric acid supplied from the cathode side concentrated sulfuric acid supply pipe 29 to the cathode side concentrated sulfuric acid supply unit 39 via the cathode side concentrated sulfuric acid supply valve 30 is supplied from the cathode side pure water supply pipe 12 to the cathode side in the cathode side tank 38. It is diluted with pure water supplied to the cathode side tank 38 via the pure water supply valve 13 and becomes diluted sulfuric acid having a low concentration.
  • the diluted sulfuric acid is adjusted to a desired temperature and concentration while circulating in the loop A ′.
  • the diluted sulfuric acid adjusted to a desired temperature and concentration is supplied to the cathode chamber 7 of the electrolytic cell 2 provided in the loop B ′ and electrolyzed.
  • the pure water supplied into the cathode side tank 38 may be quantified by using an unillustrated integrated flow meter or a liquid level meter provided in each tank and supplied to the cathode side tank 38.
  • An ultrasonic type, electromagnetic type, Coriolis type, or the like can be used for the integrating flow meter, and the control device controls the supply or stoppage of pure water based on the measured value or signal from the integrating flow meter or the liquid level sensor.
  • the installation location may be anywhere.
  • the cathode side electrolysis loop B ' is arranged and configured in a loop shape by the cathode chamber 7 of the electrolytic cell 2, the cathode side circulation pipe 44, the cathode side tank 38, and valves arranged in the middle of each pipe.
  • dilute sulfuric acid is electrolyzed, but the electrode reaction is only hydrogen gas generation, and no electrolytic sulfuric acid is generated. Therefore, in the loop B ′, a desired temperature and Diluted sulfuric acid adjusted to the concentration is circulated.
  • the anode side concentrated sulfuric acid supply unit 32 and the cathode side concentrated sulfuric acid supply unit 39 can be arranged on either the inlet side or the outlet side of the anode side circulation pump 33 and the cathode side circulation pump 40.
  • concentrated sulfuric acid is supplied to the pressurized pure water, there is a possibility of further pressure increase due to significant heat generation and bubbles generated due to the dilution of concentrated sulfuric acid at the portion where the pressure is increased. It is preferable to arrange the anode side circulation pump 33 and the cathode side circulation pump 40 on the inlet side.
  • the sulfuric acid concentration can be adjusted by the volume ratio of concentrated sulfuric acid whose concentration is known and the amount of pure water supplied to the anode side diluted sulfuric acid production loop A and the cathode side diluted sulfuric acid production loop A ′.
  • the volume of each liquid can be quantified and controlled using an integrating flow meter or the like.
  • a conductive diamond electrode as the anode 3.
  • an electrode catalyst such as Pt or PbO 2
  • the oxygen overvoltage is high, so the persulfuric acid generation efficiency is high, and the durability is high both chemically and mechanically. Therefore, it is possible to produce a sulfuric acid solution which is a highly clean electrolytic solution and an electrolytic sulfuric acid which is an electrolytic product. For the above reason, it is desirable to use a conductive diamond electrode for the anode 3 used in the electrolytic cell 2.
  • the cathode 6 it is desirable to use a conductive diamond electrode having excellent corrosion resistance from the viewpoint of cleanliness, but noble metals such as platinum and valve metals such as titanium, zirconium, tantalum and niobium having corrosion resistance against sulfuric acid. Furthermore, an electrode made of a carbon material such as graphite or glassy carbon can also be used.
  • the concentration of sulfuric acid is adjusted by adjusting the temperature by circulating cooling by the loop A ′ flowing through the cathode side bypass pipe 43 while preventing the solution from passing through the electrolytic cell 2. Adjustments are being made.
  • the anode gas generated in the anode chamber of the electrolytic cell 2 may contain toxic ozone.
  • an ozone decomposing catalyst 93 is installed behind the anode mist separator 92 as an ozone detoxifying means 93 to reduce ozone to be detoxified by oxygen, or it is sufficiently diluted with air or inert gas. It is desirable to release it outside.
  • the ozonolysis catalyst manganese peroxide is often used, but when it comes into contact with an acid solution such as sulfuric acid having a low pH, the manganese peroxide is dissolved and the ozone resolution may be lost.
  • the piping used for gas supply is generally a metal piping such as stainless steel. Since corrosion occurs due to contact with sulfuric acid mist and condensation, it is basically necessary not to discharge electrolytic gas containing them outside the apparatus.
  • a hydrogen combustion catalyst is installed behind the cathode-side mist separator 97 to mix the generated hydrogen gas and air. It is desirable to burn it and convert it into harmless water vapor and discharge it, or to dilute it sufficiently with air or inert gas and discharge it outside the apparatus.
  • the hydrogen combustion catalyst has a function of removing hydrogen by burning air and hydrogen, but a catalyst containing a noble metal is often used as an active component for combustion. Generally, when the catalyst surface is covered with a liquid such as water, the hydrogen combustion ability is lost because the hydrogen gas and the catalyst cannot be contacted.
  • the piping used for gas supply is generally a metal piping such as stainless steel. Since corrosion occurs due to contact with sulfuric acid mist and condensation, it is basically necessary not to discharge electrolytic gas containing them outside the apparatus.
  • the anode-side gas-liquid separation mechanism 91 and the cathode-side gas-liquid separation mechanism 96 separate electrolytically generated gas and sulfuric acid using a specific gravity difference between the electrolytic gas and the liquid in the electrolytic gas using a vessel such as a pipe or a tank. Or a mechanism in which the residence time of the electrolytic gas in the container is made long so that mist falls in the container.
  • a vessel such as a pipe or a tank.
  • a mechanism in which the residence time of the electrolytic gas in the container is made long so that mist falls in the container.
  • the mist separators 92 and 97 those using a mesh or a porous material having chemical resistance in a cylindrical container, or those in which the mist falls by taking a long residence time of the electrolytic gas are used. be able to.
  • the saturated water vapor pressure is lowered, thereby condensing moisture in the electrolytic gas, and the moisture removal efficiency in the gas-liquid separation mechanism and mist separator. It is also an effective means to increase the size and reduce the amount taken out to the rear line.
  • anode-side gas-liquid separation mechanism 91 When a large amount of vapor or mist is mixed in the anode-side gas-liquid separation mechanism 91, the cathode-side gas-liquid separation mechanism 96, the anode-side mist separator 92, and the cathode-side mist separator 97, liquid is stored inside to block the gas flow path. In some cases, however, the anode side tank 31 and the cathode side tank 38 cannot be exhausted. Therefore, it is preferable that the anode-side gas-liquid separation mechanism 91, the cathode-side gas-liquid separation mechanism 96, the anode-side mist separator 92, and the cathode-side mist separator 97 periodically drain the liquid stored therein. .
  • the drainage of the anode side gas-liquid separation mechanism 91 and the anode side mist separator 92 is performed from the anode side drainage pipe 95 by opening the anode side gas pipe drainage valve 94.
  • the cathode side gas / liquid separation mechanism 96 and the cathode side mist separator 97 are drained from the cathode side drain pipe 100 by opening the cathode side gas pipe drain valve 99.
  • a specified amount of pure water is first stored in the anode-side tank 31 or the pipe, and a specified amount of sulfuric acid is injected and mixed in the middle of the circulation.
  • a specified amount of sulfuric acid is injected and mixed in the middle of the circulation.
  • the gas in the anode-side tank 31 is gradually discharged out of the anode-side tank 31 (upper part of the anode gas vent pipe 102) to generate an air flow.
  • the air flows the water droplets adhering to the wall surface move through the anode gas vent pipe 102.
  • the fine bubbles move from the electrolyte solution to the gas phase in the anode side tank 31, but when the fine bubbles are repelled on the liquid surface, fine splashes are generated, and this is a gas in the anode side tank 31 as a mist. Will be included.
  • the anode-side mist separator 92 connected to the upper part of the anode-side gas-liquid separation mechanism 91 prevents gas molecules and mist (gas because it is fine) by preventing the separation membrane having fine pores from passing therethrough. (Droplet floating in the inside) can be separated. As the amount of mist separated by the separation membrane increases, it gradually becomes droplets and can flow as a liquid. The liquid a separated by the anode-side gas-liquid separation mechanism 91 flows below the gas-liquid separation mechanism 91 due to gravity (self-weight).
  • the mist separated by the anode-side mist separator 92 is collected to form droplets, which flow under the anode-side mist separator 92 due to their own weight, and shift to the anode-side gas-liquid separation mechanism 91.
  • the liquid b separated by the anode side mist separator 92 flows to the lower side of the anode side gas-liquid separation mechanism 91 in the anode side gas-liquid separation mechanism 91 in the same manner as the liquid a.
  • the liquids a and b flowing below the anode-side gas-liquid separation mechanism 91 gather in front of the anode-side gas pipe drain valve 94 and are discharged by their own weight when the anode-side gas pipe drain valve 94 is opened. Is done.
  • the relationship of the height position of each device is important. At least the anode-side mist separator 92 and the anode-side gas-liquid separation mechanism are sequentially arranged from the top. 91, anode side gas piping drainage valve 94 is required. The timing for opening and closing the gas pipe drain valve 94 can be arbitrarily selected. The same applies to the cathode side mist separator 97 connected to the upper part of the cathode side gas-liquid separation mechanism 96.
  • a pressure difference In order to efficiently drain the gas-liquid separation mechanism and the mist separator, it is preferable to use a pressure difference.
  • a decompressor (not shown) is provided in the anode-side drainage pipe 95 and the cathode-side drainage pipe 100, and a gas flow in the opposite direction to the anode gas and the cathode gas is created by decompressing the gas-liquid separation mechanism and the mist separator.
  • the sulfuric acid in the gas-liquid separation mechanism and the mist separator can be efficiently drained.
  • an inert gas supply unit (not shown) is provided on the outlet side of the anode mist separator 92 and the cathode mist separator 97, and the gas-liquid separation mechanism and the mist separator are disposed in the opposite direction to the anode gas and the cathode gas.
  • an inert gas for example, nitrogen gas can be used.
  • the diaphragm 5 used in the electrolytic cell 2 is preferably a porous fluororesin membrane or a fluororesin cation exchange membrane that has been subjected to a hydrophilic treatment.
  • a fluororesin-based cation exchange membrane When using a fluororesin-based cation exchange membrane, the sulfuric acid concentration of the anode increases as the electrolysis time elapses due to the influence of accompanying water when the cation permeates the ion exchange membrane from the anode side to the cathode side. As it rises, the amount of liquid on the anode side decreases, and the sulfuric acid concentration on the cathode decreases as it is diluted with entrained water, and the amount of liquid increases.
  • the amount of liquid on the cathode side is controlled by opening and closing the cathode tank discharge valve 113. Whether the discharge is performed periodically or the liquid level of the tank is controlled, the cathode tank discharge valve 113 is opened so that the apparatus can be controlled by its own weight. Drain liquid outside.
  • the discharge amount can be managed in various ways. For example, a liquid level sensor for measuring the Low position is provided in the cathode side tank 38, and when the liquid level has reached the sensor position after the liquid discharge has progressed, the cathode It can be managed by closing the tank discharge valve 113.
  • the timing at which the cathode tank discharge valve 113 is opened includes a case where the electrolysis time and the energization current value are monitored, the amount of entrained water is calculated from them, and the cathode tank discharge valve 113 is opened when the specified value is reached.
  • Either a surface sensor may be used, and the surface sensor may be opened when accumulating water accumulation advances and the liquid level increases to the sensor position.
  • the gas that balances the space in the cathode side tank 38 can be introduced from the cathode gas abatement device 98 through the cathode gas vent pipe 103.
  • the liquid level of the cathode side tank 38 rises and exceeds the capacity of the cathode side tank 38. Therefore, in the cathode side tank 38, the tank liquid level reaches a predetermined height. Occasionally, the cathode tank discharge valve 113 is opened, and a predetermined amount of liquid is discharged from the cathode tank discharge pipe 112 to prevent an excessive storage amount.
  • a liquid level sensor not shown can be used for the management of the liquid level of the cathode side tank 38.
  • the liquid in the cathode side tank 38 is periodically added. By discharging a predetermined amount when the surface reaches a predetermined height, overflow of the cathode side tank 38 can be prevented.
  • the sulfuric acid at the cathode is further diluted with entrained water, the concentration is lowered, and the conductivity is greatly lowered.
  • the sulfuric acid concentration of the catholyte is monitored by a sulfuric acid concentration meter (not shown) so that concentrated sulfuric acid is replenished from the cathode-side sulfuric acid supply unit 39 so as to obtain a constant concentration. It can also be controlled.
  • the electrolysis time and current value are measured, the amount of entrained water calculated from the measured value is obtained, and then the amount of entrained water is added to the amount of electrolyte in the cathode side tank 38 adjusted before electrolysis and the sulfuric acid concentration.
  • the calculated sulfuric acid concentration is less than the specified range, the amount of sulfuric acid to be added to return to the specified range is calculated, and the calculated amount of sulfuric acid is quantified with a flow meter.
  • the concentration of sulfuric acid in the catholyte can be controlled by injecting concentrated sulfuric acid from the cathode side sulfuric acid supply unit 39 to the operating state of the cathode side electrolytic loop B ′. In order to reduce the fluctuation of the electrolysis conditions, it is important to control the temperature control and the concentration of sulfuric acid supplied to the cell so as not to deviate from the specified range by slowing the injection rate of concentrated sulfuric acid.
  • the electrolytic sulfuric acid in the anode side tank 31 that has reached a predetermined oxidizable substance concentration after electrolysis for a predetermined time is removed from the apparatus through the anode tank discharge pipe 110 and the anode tank discharge valve 111.
  • the cathode side electrolysis section B ′ of the cathode side electrolysis unit 23 after electrolysis for a predetermined time, the electrolyte solution in the cathode side tank 38 is discharged out of the apparatus through the cathode tank discharge pipe 112 and the cathode tank discharge valve 113.
  • the catholyte When the electrolytic sulfuric acid in the anode side tank 31 becomes empty, the adjustment of the sulfuric acid concentration is started again. At this time, in order to reduce the amount of chemicals used, the catholyte should be used for concentration control, monitor characteristic values such as concentration and conductivity, and be used repeatedly as long as the characteristic values maintain specified values. .
  • the temperature and concentration management on the cathode side are not directly related to the persulfuric acid production efficiency, it is preferably managed for the following reasons. That is, the catholyte transmits the temperature to the anolyte through the diaphragm 5 which is a cation exchange membrane and prevents the anolyte temperature from being within a specified range.
  • the membrane 5 as an exchange membrane serves as an interface for the difference in concentration between the two polar solutions, so that it becomes a place for generating heat of dilution, making it difficult to control the temperature of the electrolyte, affecting the efficiency of producing persulfuric acid, and being a cation exchange membrane by overheating. Since the diaphragm 5 is deteriorated or changes its dimensions, or water vapor bubbles are generated due to overheating and the resistance of the cell is increased, the temperature and concentration on the cathode side must be controlled.
  • FIG. 2 is a diagram showing a sulfuric acid concentration adjustment and electrolysis process of the sulfuric acid electrolysis apparatus 1 of FIG.
  • the process in the anode side electrolysis part 20 consists of the following each process, as shown in FIG.
  • Concentrated sulfuric acid and pure water are mixed by supplying concentrated sulfuric acid from the anode side concentrated sulfuric acid supply unit 32 to the pure water circulating in the loop A and continuously circulating it.
  • the solution since the solution enters the anode-side cooler 34 immediately after the concentrated sulfuric acid and pure water are mixed, the heat of dilution generated when the concentrated sulfuric acid and pure water are mixed is immediately removed, and generation of steam and mist occurs. It is suppressed. Furthermore, the temperature rise of the anode-side concentrated sulfuric acid supply unit 32 due to the dilution heat is suppressed, and surrounding piping, pumps, valves, and the like can be protected from damage or deformation due to high heat.
  • Sulfuric acid temperature and concentration adjusting step The dilute sulfuric acid solution is mixed while circulatingly cooling in the loop A until the temperature reaches a desired temperature or lower, preferably 30 ° C or lower. Since a solution having a sulfuric acid temperature of 30 ° C. or lower has high current efficiency for generating an oxidizing substance, it is preferably cooled to 30 ° C. or lower before electrolysis.
  • the sulfuric acid concentration is preferably 2 to 10 mol / L.
  • the sulfuric acid concentration is preferably within the above range.
  • Concentrated sulfuric acid supply step Concentrated sulfuric acid and pure water are mixed by supplying concentrated sulfuric acid from the cathode-side concentrated sulfuric acid supply unit 39 to the pure water circulating in the loop A 'and continuously circulating the concentrated sulfuric acid.
  • the solution since the solution enters the cathode side cooler 41 immediately after mixing concentrated sulfuric acid and pure water, the heat of dilution generated when the concentrated sulfuric acid and pure water are mixed is immediately removed, and the generation of steam and mist is suppressed. Is done.
  • Sulfuric acid temperature and concentration adjusting step The dilute sulfuric acid solution is circulated and cooled in the loop A ′ until the temperature becomes a desired temperature or lower, preferably 30 ° C. or lower, and mixed until uniform.
  • the solution is preferably cooled to 30 ° C. or lower before electrolysis.
  • the sulfuric acid concentration is preferably 2 to 10 mol / L.
  • the steps 1) to 5) performed on the anode side and the cathode side are the same and can be performed completely independently.
  • diluted sulfuric acid adjusted to a desired temperature and a desired concentration is produced as anode side electrolytic sulfuric acid.
  • Electrolysis is performed in the electrolysis process of the loop B and the cathode side electrolysis loop B ′.
  • Electrolysis step is a step of electrolyzing a dilute sulfuric acid solution, which is performed after steps 1) to 5) are completed on both the anode side and the cathode side.
  • Both the anode side electrolysis unit 20 and the cathode side electrolysis unit 23 perform electrolysis by circulating a diluted sulfuric acid solution. Since current efficiency is high when the solution temperature is 30 ° C. or lower, the solution temperature during electrolysis is preferably controlled to 30 ° C. or lower.
  • Anolyte (electrolytic sulfuric acid) supply step The electrolytic sulfuric acid generated in the electrolysis step is adjusted to a desired temperature and a desired concentration in the loop B of the anode side electrolysis unit 20 and then supplied from the use point. This is called an electrolytic sulfuric acid supply process.
  • this electrolytic sulfuric acid solution supply step after the electrolysis for a predetermined time in the electrolysis step, or by monitoring the oxidizing substance concentration with a concentration monitor (not shown), the anolyte whose concentration has reached the predetermined concentration is supplied outside the system. It is. Although it is supplied to a resist stripping apparatus, an etching apparatus, or the like, the apparatus and equipment to be connected are not limited.
  • a concentration monitor for measuring the oxidizing substance concentration and sulfuric acid concentration can be installed in the apparatus or in an external pipe through which electrolytic sulfuric acid passes.
  • the measured value obtained by the concentration monitor is the control of the current value supplied to the electrolysis cell, the operation signal to the device to which electrolytic sulfuric acid is fed from the sulfuric acid electrolysis device such as a cleaning device, the signal of the liquid feed signal and alarm Can be used for determining the output timing.
  • the concentration monitor measurement method is not particularly limited.
  • Catholyte draining process When the catholyte increases due to entrained water during the electrolysis process and the liquid level of the cathode side tank 38 reaches a predetermined position, the cathode tank discharge valve 113 is temporarily opened, and a small amount of the catholyte is discharged. Drain the liquid.
  • the catholyte produced in the electrolysis step is discharged from the cathode side electrolysis loop B ′ of the cathode side electrolysis part 23. This is called a catholyte draining process. In the catholyte draining step, the entire amount of catholyte diluted with entrained water is drained from the cathode side tank 38.
  • the concentration drops to a predetermined value. It may be drained.
  • the cathode draining process may be performed simultaneously with the anolyte supplying process, but cannot be performed simultaneously with the electrolysis process.
  • two or more anode-side tanks may be mounted in the anode-side electrolysis unit 20, for example, for each tank, dedicated to liquid feeding outside the apparatus, dedicated to dilute sulfuric acid adjustment,
  • the cathode side electrolysis unit 23 can be provided with a mechanism having a plurality of tanks.
  • the sulfuric acid electrolysis apparatus 1 may be equipped with two or more electrolytic cells 2 or may have a bipolar structure by installing two or more pairs of positive and negative electrodes in one electrolytic cell.
  • FIG. 3 is a diagram illustrating an example in which a plurality of anode-side tanks are installed in the anode-side electrolysis unit 20.
  • the cathode side electrolysis part 23 is not illustrated, it is the same as the cathode side electrolysis part 23 in FIG.
  • the switching valves 51 to 1 shows a sulfuric acid electrolysis apparatus capable of generating electrolytic sulfuric acid containing an oxidizing substance having a predetermined concentration in the second anode side tank 50 by switching 58.
  • the first anode Electrolytic sulfuric acid can be supplied from the side tank 49 to the use point. By repeating this, electrolytic sulfuric acid can be continuously supplied without interruption, (2)
  • the first anode side tank 49 and the second anode side tank 50 produce and store electrolytic sulfuric acid having different sulfuric acid concentrations and oxidizing substance concentrations, and send them to two use points.
  • the liquid can be fed from one apparatus to a use process having different oxidizing power.
  • a plurality of cathode-side tanks in the cathode-side electrolysis unit 23 can be provided in the same manner as the anode-side tank.
  • FIG. 4 is a diagram showing a sulfuric acid concentration adjustment and electrolysis process of the sulfuric acid electrolysis apparatus 1 of FIG. The case of only one cooler and sulfuric acid mixer (common) is shown. First, the process shown on the left side of FIG. 4 will be described below.
  • the switching valve 55 is opened to supply pure water to the anode side tank 49 from the anode side pure water supply pipe 10.
  • the amount of water to be supplied can be quantified by closing the switching valve 55 by a signal from a liquid level sensor installed in the tank 49 or a signal from an integrating flow meter installed in the anode-side pure water supply pipe 10.
  • the switching valves 52 and 54 attached to the anode side tank 50 are closed.
  • Concentrated sulfuric acid and pure water are mixed by supplying concentrated sulfuric acid from the anode side concentrated sulfuric acid supply unit 32 to the pure water circulating in the loop A and continuously circulating the concentrated sulfuric acid.
  • the solution since the solution enters the anode-side cooler 34 immediately after the concentrated sulfuric acid and pure water are mixed, the heat of dilution that occurs when the concentrated sulfuric acid and pure water are mixed is immediately removed, and steam and mist are generated. Is suppressed. Furthermore, the temperature rise of the anode-side concentrated sulfuric acid supply unit 32 due to the dilution heat is suppressed, and surrounding piping, pumps, valves, and the like can be protected from damage or deformation due to high heat.
  • Sulfuric acid temperature and concentration adjusting step The dilute sulfuric acid solution is mixed while circulatingly cooling in the anode side dilute sulfuric acid production loop A until the temperature becomes a desired temperature or lower, preferably 30 ° C or lower. Since a solution having a sulfuric acid temperature of 30 ° C. or lower has high current efficiency for generating an oxidizing substance, it is preferably cooled to 30 ° C. or lower before electrolysis.
  • the sulfuric acid concentration is preferably 2 to 10 mol / L.
  • the sulfuric acid concentration is preferably within the above range.
  • the diluted sulfuric acid adjusted to a desired temperature and a desired concentration is electrolyzed in the electrolysis step of the anode side electrolytic sulfuric acid production loop B.
  • Electrolysis step is a step of electrolyzing the diluted sulfuric acid solution, which is performed after the above 1) to 5) are completed.
  • the cathode side is not shown in FIG. 4, the steps 1) to 5) are performed in the same manner as the anode side on the cathode side as in the case of FIG.
  • electrolysis is performed by circulating a diluted sulfuric acid solution. Since current efficiency is high when the solution temperature is 30 ° C. or lower, the solution temperature during electrolysis is preferably controlled to 30 ° C. or lower.
  • the anode side bypass valve 35 is closed, the anode chamber outlet valve 22 and the anode chamber inlet valve 21 are opened, and the anode side bypass valve 35 is circulated between the anode side tank 49 and the anode chamber 4.
  • a direct current is supplied to the electrolytic cell 2 and electrolysis is performed for a specified time at a predetermined supply current to obtain an electrolytic sulfuric acid containing an oxidizing substance having a specified concentration.
  • the switching valves 51 and 53 are closed, and the generated electrolytic sulfuric acid containing the specified concentration of oxidizing substance is stored in the anode tank 49.
  • Anolyte (electrolytic sulfuric acid) supply step The electrolytic sulfuric acid produced in the electrolysis step is adjusted to a desired temperature and a desired oxidizing substance concentration in the anode side electrolytic sulfuric acid production loop B of the anode side electrolysis unit 20. , Supplied to the point of use. This is called an electrolytic sulfuric acid supply process.
  • this electrolytic sulfuric acid solution supply step after the electrolysis for a predetermined time in the electrolysis step, or by monitoring the oxidizing substance concentration with a concentration monitor (not shown), the anolyte whose concentration has reached the predetermined concentration is supplied outside the system. It is. Although it is supplied to a resist stripping apparatus, an etching apparatus, or the like, the apparatus and equipment to be connected are not limited.
  • the switching valve 56 is opened, and pure water is supplied to the anode side tank 50 from the anode side pure water supply pipe 10.
  • the amount of water to be supplied can be quantified by closing the switching valve 56 with a signal from a liquid level sensor installed in the tank 50 or a signal from an integrating flow meter installed in the anode-side pure water supply pipe 10.
  • the switching valves 52 and 54 attached to the anode tank 50 are open.
  • Concentrated sulfuric acid and pure water are mixed by supplying concentrated sulfuric acid from the anode side concentrated sulfuric acid supply unit 32 to the pure water circulating in the loop A and continuously circulating it.
  • the solution since the solution enters the anode-side cooler 34 immediately after the concentrated sulfuric acid and pure water are mixed, the heat of dilution generated when the concentrated sulfuric acid and pure water are mixed is immediately removed, and generation of steam and mist occurs. It is suppressed. Furthermore, the temperature rise of the anode-side concentrated sulfuric acid supply unit 32 due to the dilution heat is suppressed, and surrounding piping, pumps, valves, and the like can be protected from damage or deformation due to high heat.
  • Sulfuric acid temperature and concentration adjusting step The dilute sulfuric acid solution is mixed while circulatingly cooling in the loop A until the temperature reaches a desired temperature or lower, preferably 30 ° C or lower. Since a solution having a sulfuric acid temperature of 30 ° C. or lower has high current efficiency for generating an oxidizing substance, it is preferably cooled to 30 ° C. or lower before electrolysis.
  • the sulfuric acid concentration is preferably 2 to 10 mol / L. This is because the current efficiency generated by the oxidizing substance is higher than that of sulfuric acid of 10 mol / L or more.
  • Electrolysis step is a step of electrolyzing the diluted sulfuric acid solution, which is performed after the above 1) to 5) are completed.
  • the cathode side is not shown in FIG. 4, the steps 1) to 5) are performed in the same manner as the anode side on the cathode side as in the case of FIG.
  • electrolysis is performed by circulating a diluted sulfuric acid solution. Since current efficiency is high when the solution temperature is 30 ° C. or lower, the solution temperature during electrolysis is preferably controlled to 30 ° C. or lower.
  • the anode side bypass valve 35 is closed, the anode chamber outlet valve 22 and the anode chamber inlet valve 21 are opened, and the anode side bypass valve 35 is circulated between the anode side tank 50 and the anode chamber 4.
  • a direct current is supplied to the electrolytic cell 2 and electrolysis is performed for a specified time at a predetermined supply current to obtain an electrolytic sulfuric acid containing an oxidizing substance having a specified concentration.
  • the switching valves 52 and 54 are closed, and the generated electrolytic sulfuric acid containing the specified concentration of oxidizing substance is stored in the anode tank 50. Thereafter, electrolytic sulfuric acid is supplied from the anode side tank 50 to the use point, and the pure water supply process is started again in the anode side tank 49 and is repeated.
  • Example 1 The sulfuric acid electrolysis apparatus and the sulfuric acid electrolysis method shown in FIGS. 1 and 2 were used.
  • the sulfuric acid temperature and concentration adjusting steps were as follows. Concentrated sulfuric acid was diluted with pure water to prepare diluted sulfuric acid having a predetermined concentration adjusted in temperature.
  • the procedure on the anode side is as follows. 1) Pure water was supplied from the anode side pure water supply pipe 10 to the anode side tank 31 and stored. The amount of pure water supplied was weighed and supplied using an ultrasonic flow meter (not shown). 2) The anode-side circulation pump 33 was driven to circulate pure water in the loop A. 3) Concentrated sulfuric acid was supplied into the loop A from the anode side concentrated sulfuric acid supply unit 32 to the pure water circulating in the loop A to generate diluted sulfuric acid. The supply amount of concentrated sulfuric acid was weighed and supplied using an ultrasonic flow meter (not shown).
  • the procedure on the cathode side is as follows. 1) Pure water was supplied from the cathode side pure water supply pipe 12 to the cathode side tank 38 and stored. The amount of pure water supplied was weighed and supplied using an ultrasonic flow meter (not shown). 2) The cathode-side circulation pump 40 was driven to circulate pure water in the loop A ′. 3) Concentrated sulfuric acid was supplied into the loop A ′ from the cathode-side concentrated sulfuric acid supply unit 39 to the pure water circulating in the loop A ′ to generate diluted sulfuric acid. The supply amount of concentrated sulfuric acid was weighed and supplied using an ultrasonic flow meter (not shown).
  • the anode 21 opens the valve 21 and the valve 22 and closes the valve 35 to form the loop B
  • the cathode side forms the cathode chamber inlet valve 24 and Opening the cathode chamber outlet valve 25 and closing the cathode side bypass valve 42 constitutes the cathode side electrolysis loop B ′, supplying a direct current to the electrolysis cell while supplying a dilute sulfuric acid solution to each electrolysis cell and performing electrolysis.
  • the electrolytic sulfuric acid containing an oxidizing substance was produced.
  • the sulfuric acid concentration before electrolysis was adjusted in the range of 1.8 to 16.7 mol / L after the sulfuric acid concentration adjusting step by the above-described method.
  • the concentration of the catholyte was adjusted by applying the same method to the cathode side. After the diluted sulfuric acid solution was cooled, electrolysis was performed. The conditions were as follows.
  • the diluted sulfuric acid electrolyzed according to the above procedure and conditions was sampled from a sampling pipe (not shown) branched from the electrolytic section, and the total amount of oxidizing substances produced in the diluted sulfuric acid was quantitatively measured by the KI titration method.
  • Table 1 shows a measurement example of the total oxidizable substance concentration at the same volumetric capacity density depending on the diluted sulfuric acid temperature used for electrolysis.
  • the sulfuric acid concentration is 3.7 mol / L. When temperature exceeds 30 degreeC, the density
  • Table 2 shows the results of the total oxidizing substance concentration and the current efficiency when the sulfuric acid concentration is 1.8 to 16.7 mol / L.
  • the current density was 100 A / dm 2 and the volume capacity density was 25 Ah / L.
  • the current efficiency obtained from the total oxidizable substance concentration shows a region of 60% or more when the sulfuric acid concentration is 2.0 to 10.0 mol / L, and it rapidly decreases in the thinner and dense regions. all right.
  • Table 3 shows an example in which the electrolytic solution was continuously cooled during electrolysis and maintained at 30 ° C., and an example in which cooling was stopped during electrolysis and the electrolytic solution temperature was raised to 51 ° C. due to heat generated by electrolysis.
  • Comparative Example 1 a case where the mixing position of concentrated sulfuric acid and pure water is set in the anode tank, and the gas-liquid separation mechanism and the mist separator are not provided is shown. In the diluted sulfuric acid production step of Comparative Example 1, cooling was not appropriate, and an apparatus trouble occurred.
  • Comparative Example 1 in order to prepare a 6 mol / L diluted sulfuric acid solution, 2.6 L of ultrapure water was introduced into the tank from the upper part of the tank, and then 5.9 L of 98 mass% sulfuric acid was introduced from the lower part of the tank. . All solutions were at room temperature.
  • the ultrapure water supply flow rate was 3 L / min, and the 98 mass% sulfuric acid supply flow rate was 0.2 to 1 L / min.
  • the vapor generated by the heat of dilution of sulfuric acid retains mist generated during the dilution of sulfuric acid and the liquid condensed in the vapor inside the filter installed between the cathode tank and the hydrogen combustion tower installed as the cathode-side abatement equipment. Since the gas filter was blocked by this liquid, the cathode gas was retained between the cathode tank and the filter, and high pressure was generated. After releasing the residual pressure, the cell was disassembled, and through holes were found in the cation exchange membrane.
  • the sulfuric acid electrolysis apparatus and the sulfuric acid electrolysis method of the present invention by generating diluted sulfuric acid whose temperature and concentration are controlled in the apparatus, and further electrolyzing the diluted sulfuric acid under temperature-controlled conditions, Sulfuric acid containing an oxidizing substance can be produced efficiently and safely. Furthermore, the present invention provides a sulfuric acid electrolysis apparatus and a sulfuric acid electrolysis method capable of producing a high-concentration oxidizing material solution that could not be achieved by the prior art with high current efficiency and capable of stably producing an oxidizing active material. be able to.
  • anode side tank 50 second anode side tank 51 to 58: switching valve 91: anode side gas-liquid separation mechanism 92: anode side mist separator 93: ozone decomposition mechanism 94: anode side gas piping drain valve 95: anode Side drainage pipe 96: Cathode side gas-liquid separation mechanism 97: Cathode side mist separator 98: Cathode gas abatement equipment 99: Cathode side gas pipe drain valve 100: Cathode side drain pipe 102: Anode gas vent pipe 103: Cathode gas vent Pipe 110: Anode tank discharge pipe 111: Anode tank discharge valve 112: Cathode tank discharge pipe 113: Cathode tank discharge valve

Abstract

La présente invention se rapporte à un appareil permettant la production d'acide sulfurique qui contient une grande quantité d'une substance oxydante par électrolyse de l'acide sulfurique et, de façon précise, se rapporte à un appareil permettant de produire de manière sûre et extrêmement efficace de l'acide sulfurique électrolysé qui contient une grande quantité d'une substance oxydante par production de l'acide sulfurique dilué dont la température et la concentration sont régulées dans un appareil d'électrolyse et, ensuite, par électrolyse de l'acide sulfurique dilué sous des conditions de régulation de la température. La présente invention porte sur un appareil permettant l'électrolyse de l'acide sulfurique. Ledit appareil comprend une unité d'électrolyse côté électrode positive et une unité d'électrolyse côté électrode négative et est pourvu, au moins dans l'unité d'électrolyse côté électrode positive : d'une boucle A de production d'acide sulfurique dilué côté électrode positive destinée à diluer l'acide sulfurique concentré qui constitue la matière première qui est fournie, et, ensuite, à ajuster la température et la concentration de l'acide sulfurique ainsi dilué à des valeurs souhaitées ; et d'une boucle B de production d'acide sulfurique électrolysé côté électrode positive destinée à produire de l'acide sulfurique électrolysé par électrolyse de l'acide sulfurique dilué dont la température et la concentration sont ajustées à des valeurs souhaitées dans la boucle A et, ensuite, à ajuster la température et la concentration de l'acide sulfurique électrolysé ainsi produit à des valeurs souhaitées. La présente invention porte également sur un procédé permettant l'électrolyse de l'acide sulfurique.
PCT/JP2012/055754 2011-03-08 2012-03-07 Appareil permettant l'électrolyse de l'acide sulfurique et procédé permettant l'électrolyse de l'acide sulfurique WO2012121270A1 (fr)

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US14/001,636 US20130334059A1 (en) 2011-03-08 2012-03-07 Apparatus for electrolyzing sulfuric acid and method for electrolyzing sulfuric acid
CN201280022515.0A CN103518007A (zh) 2011-03-08 2012-03-07 硫酸电解装置以及硫酸电解方法
KR1020137026473A KR101551049B1 (ko) 2011-03-08 2012-03-07 황산 전해 장치 및 황산 전해 방법
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JP2020056093A (ja) * 2018-05-16 2020-04-09 住友金属鉱山株式会社 硫酸溶液の製造方法およびこの製造方法で用いられる電解槽

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JP5997130B2 (ja) 2016-09-28
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TW201243109A (en) 2012-11-01
TWI518209B (zh) 2016-01-21

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