WO2003082793A1 - Procede de recuperation d'emulsifiant contenant du fluor - Google Patents

Procede de recuperation d'emulsifiant contenant du fluor Download PDF

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Publication number
WO2003082793A1
WO2003082793A1 PCT/JP2003/003845 JP0303845W WO03082793A1 WO 2003082793 A1 WO2003082793 A1 WO 2003082793A1 JP 0303845 W JP0303845 W JP 0303845W WO 03082793 A1 WO03082793 A1 WO 03082793A1
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WIPO (PCT)
Prior art keywords
emulsifier
fluorine
fluorinated emulsifier
aqueous liquid
fluorinated
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PCT/JP2003/003845
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English (en)
Japanese (ja)
Inventor
Hiroshi Funaki
Masataka Eda
Hiroki Kamiya
Koichi Yanase
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Asahi Glass Company, Limited
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Application filed by Asahi Glass Company, Limited filed Critical Asahi Glass Company, Limited
Publication of WO2003082793A1 publication Critical patent/WO2003082793A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/20—Halogens or halogen compounds
    • B01D2257/206—Organic halogen compounds
    • B01D2257/2066—Fluorine
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/30—Capture or disposal of greenhouse gases of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]

Definitions

  • the present invention relates to a method for recovering a fluorinated emulsifier contained in exhaust gas.
  • a fluorinated emulsifier contained in exhaust gas from a drying step and a heat treatment step of the fluorinated polymer is collected in a gas absorption tower.
  • Methods of contact absorption in a solvent or solution are known.
  • IER anion exchange resin
  • APFO ammonium perfluorooctanoate
  • WO 99/62830 discloses that nonionic or ionic surfactants are added to flocculated wastewater of a fluoropolymer to stabilize polytetrafluoroethylene (hereinafter referred to as PTFE) fine particles in the flocculated wastewater, A method for preventing clogging of a packed tower is described.
  • PTFE polytetrafluoroethylene
  • JP-A-55-120630, US Pat. No. 4,369,266 and DE2908001 describe that PTFE coagulated wastewater is concentrated by ultrafiltration and a part of APFO used for PTFE production is recovered, and then APER is adsorbed and recovered by IER. The method is described.
  • JP-A-55-104651, US4282162 and DE2903981 describe a method in which APFO is adsorbed on ER, and then perfluoractonic acid is desorbed and recovered using a mixture of an acid and an organic solvent.
  • WO 99Z62858 discloses that lime water is added to the coagulated waste water of a tetrafluoride tyrennoperfluoro (alkylvinyl ether) copolymer (hereinafter referred to as PFA) to adjust the pH to 6 to 7.5. After adjusting to pH, non-agglomerated PFA is aggregated by adding metal salts such as aluminum chloride and iron chloride, and then the aggregates are mechanically separated and removed. The following describes a method for preparing and adsorbing and recovering APFO using a strongly basic IER.
  • PFA tetrafluoride tyrennoperfluoro (alkylvinyl ether) copolymer
  • WO 02/10104 and WO 02/10105 further disclose adding a divalent metal salt and a trivalent metal salt to a solution containing a fluorine-based compound or a solution containing a fluorine-based compound and a fluorine-containing polymer.
  • the fluorine-based compound By precipitating a layered double hydroxide containing a compound between the layers, the fluorine-based compound is fixed at a high ratio, and if necessary, the precipitated layered double hydroxide is recovered, and the fluorine-based compound or the fluorine-containing compound between the layers is recovered.
  • a method for separating salts is described.
  • An object of the present invention is to provide a method capable of efficiently recovering a fluorine-containing emulsifier contained in an exhaust gas. Disclosure of the invention
  • the present inventors have made intensive studies on the recovery of the fluorinated emulsifier from the exhaust gas, and as a result, the exhaust gas from the drying step and the heat treatment step of the fluorinated polymer contains a large amount of carbon dioxide gas together with the fluorinated emulsifier. It has been found that the carbon dioxide gas has various effects on the recovery of the fluorine-containing emulsifier. For example, when the exhaust gas is brought into contact with the aqueous solution of the layered double hydroxide, immobilization of the fluorinated emulsifier between layers due to carbon dioxide gas or the like becomes insufficient, and the recovery cannot be increased. In addition, even when the high-concentration alkaline aqueous solution is used, difficulties such as foaming and the like arise due to contact of a large amount of carbon dioxide and the like with a high-concentration alkaline aqueous solution.
  • the present inventor has newly found that the above problems can be smoothly and advantageously solved by bringing an exhaust gas containing a fluorinated emulsifier into contact with a specific aqueous liquid to perform an absorption operation.
  • an exhaust gas (A) containing a fluorinated emulsifier is brought into contact with an aqueous liquid (B1) having a pH of 7 to less than 12, and the fluorinated emulsifier in the exhaust gas is absorbed into the aqueous liquid.
  • the present invention provides a method for bringing an exhaust gas (A) containing a fluorinated emulsifier into contact with an aqueous liquid (B1) having a pH of 7 or more and less than 12 to absorb the fluorinated emulsifier in the exhaust gas into the aqueous liquid.
  • step (XI) for fixing the fluorinated emulsifier in the mixed aqueous liquid (B 4) between the layers of the layered double hydroxide, and the layered composite having the fluorinated emulsifier fixed between the layers obtained in the step (Y).
  • the present invention provides a method for recovering a fluorinated emulsifier, which comprises a recovery step (Z) for separating a hydroxide (C) and recovering the fluorinated emulsifier.
  • the exhaust gas (A) in the present invention is not particularly limited as long as it is an exhaust gas containing a fluorinated emulsifier, and is usually a fluorinated polymer obtained by emulsion polymerization or aqueous dispersion polymerization in an aqueous medium containing a fluorinated emulsifier. Exhaust gas from one drying and Z or heat treatment step is preferred.
  • an aqueous dispersion of a fluorinated polymer obtained by emulsion polymerization or aqueous dispersion polymerization of a fluorinated monomer or a fluorinated monomer and a monomer other than the fluorinated monomer in an aqueous medium containing a fluorinated emulsifier
  • the fluorinated polymer is coagulated and separated by salting out or the like, and the separated fluorinated polymer is discharged from the heat treatment apparatus when drying and / or heat treatment is performed using a heat treatment apparatus such as an oven.
  • Exhaust gas containing a trace amount of solid fine powder Exhaust gas containing a trace amount of solid fine powder.
  • the exhaust gas is used as the exhaust gas (A) will be described as a representative.
  • step (X) the exhaust gas (A) is brought into contact with an aqueous liquid (B 1) having a pH of 7 or more and less than 12 to absorb the fluorinated emulsifier in the exhaust gas into the aqueous liquid. At least, an aqueous liquid (B 2) containing a fluorinated emulsifier is obtained.
  • a method for absorbing the fluorinated emulsifier into the aqueous liquid (B 2) a generally known gas absorbing device method can be used.
  • a gas absorption method a liquid film type, a droplet type, a bubble type, a foam type and the like can be used.
  • Examples of the gas absorbing device include, as a liquid film type, a packed tower, a wet wall tower, a submerged tower, a liquid jet, a ball tower, a disk tower, a toril, a seralysturil, and a Tyler absorbing device.
  • Examples of the droplet type include a spray tower, a disk rotary absorption device, a cyclone scrubber, a venturi scrubber, a packed fluidized bed absorption device, a centrifugal absorption device, and the like.
  • the bubble type includes a bubble column, a bubble stirring tank, and the like. A column can be exemplified.
  • examples of the foam type include foam separation.
  • a droplet type absorption device Z or a liquid film type absorption agent is used. It is preferable to use the device for reasons such as absorption efficiency and maintenance and inspection of the device.
  • the exhaust gas (A) may be used in a gas absorption device such as an absorption tower (hereinafter, may be represented by an absorption tower).
  • the linear velocity is not particularly limited, but is preferably from 0.01 m / sec to 10 m / sec, more preferably from 0.01 lm / sec to 5 mZ seconds, and particularly preferably from 0.01 mZ seconds to 3 mZ seconds.
  • step (X) it is also preferable to equip a gas absorption tower with a droplet separation device (demister) to prevent the droplets from being entrained in the next step.
  • a droplet separation device demister
  • the amount of the aqueous liquid (B1) used in the step (X) is not particularly limited, but when the concentration of the fluorinated emulsifier in the obtained aqueous liquid (B2) is high, the processing speed is rapidly reduced due to foaming. Therefore, control the flow rate of the exhaust gas (A) and the amount of the aqueous liquid (B1) so that the concentration of the fluorinated emulsifier in the aqueous liquid (B2) is 10% by mass or more and 1% by mass or less. Is preferred.
  • Water is usually used as a raw material of the aqueous liquid (B1) in the step (X).
  • the type of the water is not particularly limited, but adverse effects such as foaming of the aqueous liquid (B 1) or the aqueous liquid (B 2) due to the fluorinated emulsifier and contaminants contained in the exhaust gas (A), scaling to the absorption device, and the like. It is preferable to use ion-exchanged water from the viewpoint of preventing water leakage.
  • the wastewater (B3) after separating the fluorine-containing polymer in the production process of the fluorine-containing polymer can be used as the aqueous liquid (B1).
  • the aqueous liquid (B1) is preferably an aqueous liquid whose pH has been adjusted to 7 or more and less than 12 using an alkali.
  • the temperature at the time of contact between the exhaust gas (A) and the aqueous liquid (B1) in the step (X) is not particularly limited, but is usually preferably 10 to 60 ° C.
  • the temperature can be controlled by the temperature of the exhaust gas (A) and / or the aqueous liquid (B1), but it is usually practical and preferable to adjust the temperature by the temperature of the aqueous liquid (B1).
  • the temperature of the aqueous liquid (B 1) is preferably from 10 ° C. to 60 ° C. in consideration of the solubility of the alkali and the fluorinated emulsifier.
  • the alkali used for the aqueous liquid (B1) is not particularly limited, but may be sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, calcium hydrogen carbonate, An example is an ammonia monitor.
  • sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, or ammonia are more likely to occur. preferable.
  • the pH of the aqueous liquid used for gas absorption is basically preferable from the viewpoint of the properties of the fluorinated emulsifier to be absorbed. Is 7 or more and less than 12.
  • the pH of the aqueous liquid (B1) is preferably 8 to 11.
  • the step (Y), that is, the step (Y) of fixing the fluorine-containing emulsifier between the layers of the layered double hydroxide to the aqueous liquid (B2) after gas absorption obtained in the step (X) is performed. Therefore, it is also preferable to previously adjust the H of the aqueous liquid (B1) to a pH suitable for the layered double hydroxide.
  • the wastewater (B3) after separating the fluoropolymer in the production process of the fluoropolymer may be used as the aqueous liquid (B1) in the step (X). Further, after passing through the step (XI) of mixing the aqueous liquid (B2) obtained in the step (X) with the waste water (B3), the mixed aqueous liquid (B4) is obtained.
  • aqueous liquid (B2) containing the fluorinated emulsifier including the case where the wastewater (B3) is used and the case where the mixed aqueous liquid (B4) is used.
  • the fluorinated emulsifier is fixed between the layers of the layered double hydroxide, and the fixation is performed by adsorbing the anion of the fluorinated emulsifier on the layered double hydroxide.
  • coprecipitation In general, three types of anion adsorption by layered double hydroxide are known: coprecipitation, ion exchange, and reconstruction. '' In the coprecipitation method, metal ions are added to the solution in which the recovery anion is dissolved to form a layered double hydroxide, and at the same time, the recovery anion is included between the layers of the layered double hydroxide. It is a way to make it.
  • the replacement method is to prepare in advance a layered double hydroxide having a structure in which anions other than the target anion (eg, chloride ion, hydroxide ion, carbonate ion, etc.) are included between the layered double hydroxide layers. In this method, the layered double hydroxide is added to a solution in which the recovery anion is dissolved, and the recovery objective anion is included between the layers so as to replace the already encapsulated anion.
  • anions other than the target anion eg, chloride ion, hydrox
  • a layered double hydroxide containing carbonate ions between the layers is synthesized, and calcined at a high temperature of 400 to 500 ° C to remove the carbonate ions inside.
  • This is a method in which the anion to be recovered is included in the layered double hydroxide by adding it to a liquid in which the anion to be recovered is dissolved.
  • any of the above-mentioned methods can be employed in the step (Y), however, because the fluorine-containing emulsifier in the aqueous liquid (B 2) can be efficiently fixed between the layers of the layered double hydroxide.
  • a coprecipitation method is employed.
  • a salt such as perfluoroalkanoic acid, ⁇ -hydroperfluoroalkanoic acid, ⁇ -chloroperfluoroalkanoic acid, or perfluoroalkanesulfonic acid having 5 to 13 carbon atoms is used. Is preferred. These may have a linear structure or a branched structure, or a mixture thereof. Further, the molecule may contain an etheric oxygen atom. When the number of carbon atoms is in this range, the effect as an emulsifier is excellent.
  • the acid salt is preferably an alkali metal salt such as a lithium salt, a sodium salt or a potassium salt, or an ammonium salt, more preferably an ammonium salt or a sodium salt, and most preferably an ammonium salt.
  • the acid include perfluoropentanoic acid and perfluorohexanoic acid.
  • Perfluoroheptanoic acid perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluorododecanoic acid, ⁇ -hydroperfluoroheptanoic acid, ⁇ -hydro Perfluorooctanoic acid, ⁇ -hydroperfluorononanoic acid, ⁇ -chloroperfluoroheptanoic acid, ⁇ -chloroperfluorooctanoic acid, ⁇ monochloroperfluorononanoic acid, etc. Is mentioned.
  • ammonium salt examples include ammonium perfluoropentanoate, ammonium perfluorohexanoate, ammonium perfluoroheptanoate, ammonium perfluorooctanoate (APFO), and perfluorononanoic acid.
  • lithium salt examples include lithium perfluoropentanoate, lithium perfluorohexanoate, lithium perfluoroheptanoate, lithium perfluorosiloxane, lithium perfluorononanoate, and lithium perfluoronate.
  • sodium salt examples include sodium perfluoropentanoate, sodium perfluorohexanoate, sodium perfluoroheptanoate, sodium perfluorooctanoate, sodium perfluorononanoate, sodium perfluorodecanoate Sodium perfluorododecanoate, sodium ⁇ -hydroperfluoroheptanoate, sodium ⁇ -hydroperfluorooctanoate, sodium ⁇ -hydroperfluorononanoate, ⁇ -sodium perfluoroheptanoate, ⁇ -clo mouth sodium perfluorooctanoate, ⁇ -clo mouth sodium perfluorononanoate and the like.
  • potassium salt examples include potassium perfluoropentanoate, potassium perfluorohexanoate, potassium perfluoroheptanoate, potassium perfluorooctanoate, potassium perfluorononanoate, and perfluorophosphate
  • Potassium decanoate Pum potassium perfluorododecanoate, potassium ⁇ -hydroperfluoroheptanoate, potassium ⁇ -hydroperfluorooctanoate, potassium ⁇ -hydroperfluorononanoate, ⁇ -cloper per Potassium fluoroheptanoate, ⁇ -chlorofluorofluorooctanoic acid rim, and ⁇ -chloroperfluorononanoic acid rim.
  • potassium perfluorohexane sulfonate potassium perfluoroheptane sulfon
  • an ammonium salt of a perfluoroalkanoic acid having 6 to 12 carbon atoms is preferable, and ammonium perfluoroheptanoate, APFO, ammonium perfluorononanoate or perfluorodenoic acid is preferable.
  • Ammonium acid is more preferred, and APFO is most preferred.
  • the waste water (B3) after separating the fluoropolymer in the production process of the fluoropolymer is defined as the copolymer of the fluoromonomer or the fluoromonomer and the monomer other than the fluoromonomer.
  • the coagulated wastewater will be described as a typical example.
  • the coagulated waste water from the above-mentioned manufacturing process refers to an emulsion polymerization or an aqueous dispersion polymerization of a fluorine-containing monomer or a fluorine-containing monomer and a monomer other than the fluorine-containing monomer in an aqueous medium containing a fluorine-containing emulsifier.
  • This refers to waste water after the fluoropolymer is aggregated and separated by salting out or the like from the aqueous dispersion of the fluoropolymer obtained as above.
  • the flocculated wastewater contains the fluorinated emulsifier used during the polymerization of the fluorinated monomer.
  • the exhaust gas (A) in the present invention is an exhaust gas from the process of producing a fluoropolymer, and the exhaust gas (A) contains the fluorinated emulsifier used during the polymerization of the fluorinated monomer. It is.
  • Including a fluorine-containing emulsifier in the exhaust gas (A)
  • the concentration of the fluorine-containing emulsifier in the exhaust gas is usually 0.001 g / Nm 3 or more and 10 gZNm 3 or less, preferably 0.01 gZNm 3 or more and 1 g / Nm 3 or less.
  • TFE tetrafluoroethylene modified styrene
  • CF 2 CFC 1
  • CFH CF 2
  • CFH CH 2
  • CF 2 CH 2
  • Referred VdF Furuoroechiren such s, the hexa full O b propylene
  • fluorinated monomers may be used alone or in combination of two or more.
  • Monomers other than the fluorinated monomer include pinyl esters such as vinyl acetate, vinyl ethers such as ethylvinyl ether, cyclohexyl vinyl ether and hydroxybutyl vinyl ether, and monomers having a cyclic structure such as norpolenene and norponadiene. And aryls such as methylaryl ether, ethylene (hereinafter referred to as E), propylene (hereinafter referred to as P), and olefins such as isobutylene. Monomers other than the fluorinated monomer may be used alone or in combination of two or more.
  • examples of the fluorine-containing polymer include PTFE, TFEZP copolymer, TFEZPZVdF copolymer, TFEZHFP copolymer, TFEZPPVE copolymer, E / TFE copolymer, polyvinylidene fluoride and the like. More preferably, it is PTFE, TFEZP copolymer, exactly £ 7? / ⁇ 01 copolymer or just FEZPPVE copolymer, most preferably PTFE.
  • the fluorinated emulsifier contained in the exhaust gas (A) can be recovered, but when the waste water (B 3) is used as the aqueous liquid (B 1) or mixed through the step (X 1)
  • the fluorinated emulsifier contained in the wastewater (B3) such as coagulated wastewater (hereinafter sometimes referred to as coagulated wastewater (B3)) is also processed.
  • the layered double hydroxide can be fixed between layers, and the fluorinated emulsifier contained in both the exhaust gas ( ⁇ ⁇ ⁇ ) and the coagulated wastewater ( ⁇ 3) can be recovered together.
  • the pH of the waste water ( ⁇ 3) is reduced by hydrochloric acid and / or sulfuric acid and / or nitric acid.
  • the layered double hydroxide used in (II) it is preferable to adjust appropriately according to the layered double hydroxide used in (II). For example, when aluminum and zinc are used, it is preferably adjusted to 6 or more and less than 8, and when aluminum and magnesium are used, it is preferably adjusted to 9 or more and less than 11. If the coagulated wastewater ( ⁇ 3) is acidic, use potassium hydroxide and / or sodium hydroxide to adjust the pH of the wastewater ( ⁇ 3). As described above, when aluminum and zinc are used, 6 or more and less than 8 When using aluminum and magnesium, it is preferable to adjust the value to 9 or more and less than 11. If the pH is outside the above range, aluminum and zinc, or aluminum and magnesium each independently form a hydroxide, and form aluminum hydroxide, zinc hydroxide, and magnesium hydroxide. Is difficult to form, and as a result, the recovery efficiency of the fluorine-containing emulsifier is significantly reduced.
  • a layered double hydroxide can be formed if the formation of hydroxides of the trivalent metal and the divalent metal overlaps or the range of formation of both hydroxides is close.
  • the trivalent metal include aluminum, bismuth, cerium, and chromium.
  • examples thereof include (III), iron (III), gallium, indium, manganese (III), titanium, and titanium.
  • aluminum is preferable because of a small load on the environment and the like and availability.
  • examples of the divalent metal include beryllium, cadmium, cobalt, chromium (11), copper (II), iron (II), magnesium, manganese (11), nickel, lead (11), platinum, and palladium.
  • zinc, tin, calcium and the like can be exemplified, zinc or magnesium is preferable, and magnesium is particularly preferable because of a small load on the environment and the like and availability.
  • the concentration of the fluorinated emulsifier in the coagulated wastewater ( ⁇ 3) and the concentration of the fluorinated emulsifier in the aqueous liquid ( ⁇ 2) are preferably 1% by mass or more and 10% by mass or less, and 10% by mass or less.
  • the content is more preferably not less than ppm and not more than 1 mass%, particularly preferably not less than 50 mass ppm and not more than 0.5 mass%.
  • the layered double hydroxide in step (Y) may cause The efficiency of capturing the fluorinated emulsifier decreases. If the concentration is higher than this, a simpler and more efficient method such as precipitation of the fluorinated emulsifier by changing pH can be used.
  • suspended solids such as non-agglomerated fluoropolymer fine particles and the like that can be suspended solids (hereinafter, these are collectively referred to as SS components) contained in the aggregated wastewater (B 3) are: It does not adversely affect the fixation and the fixation ratio of the fluorinated emulsifier in the step (Y). However, in the recovery step (Z), the fluorinated emulsifier may be hindered from being regenerated from the above-mentioned layered double hydroxide (C) force. It is preferable to remove to less than mass%.
  • the SS component is more preferably removed to 0.3% by mass or less, particularly preferably to 0.05% by mass or less.
  • Substances that can become suspended solids include metal salts used for salting-out and coagulation of fluoropolymers, Z and substances precipitated by changes in pH of coagulated wastewater (B3) and Z or coagulated wastewater (B 3) Substances that precipitate when the temperature drops or rises.
  • salting-out aggregation with a metal salt containing a polyvalent metal cation is effective.
  • the metal salt (coagulant) include aluminum chloride, aluminum chloride hexahydrate, polychlorinated aluminum, ferrous chloride, and ferric chloride.
  • Agglomerates may precipitate in a state in which a fluorinated emulsifier such as APFO is contained. Therefore, the pH is adjusted to 7 or more by adding sodium hydroxide and / or a hydration-powered rim to adjust the pH to 7 or more. It is preferred to redissolve the emulsifier from the aggregates in water.
  • a general solid-liquid separation method can be employed as a method for removing the aggregates of the SS component that is aggregated by adding the metal salt to the aggregated wastewater (B 3). It is preferable to use at least one method selected from the group consisting of a station, centrifugation, and gravity sedimentation. The filtration is also preferably performed under pressure. Further, it is preferable that the wastewater containing the aggregates is allowed to stand, the aggregates are settled, and the supernatant is filtered to remove the aggregates. From the viewpoint of facility maintenance and the like, a solid-liquid separation method using a thickener or a screw decanter is most preferable.
  • the pH at the time of mixing with the aqueous liquid (B2) or the mixed aqueous liquid (B4) is preferably adjusted to 9 or more and less than 11 when aluminum and magnesium are used.
  • the molar ratio of aluminum ion: magnesium ion is 1: 2, and the concentration of aluminum ion and magnesium ion is each 0.
  • the fluorinated emulsifier is fixed between the layers of the layered double hydroxide to be formed. . There is no problem with using any of the raw materials for aluminum ion and magnesium ion.
  • Aluminum chloride, aluminum chloride hexahydrate, aluminum sulfate, and aluminum nitrate are preferred as aluminum ion raw materials because of availability, and aluminum chloride and aluminum chloride hexahydrate are particularly preferred.
  • As a raw material of magnesium ion magnesium chloride, magnesium chloride hexahydrate, magnesium nitrate hexahydrate, magnesium nitrate, magnesium sulfate, magnesium sulfate heptahydrate, and magnesium carbonate are preferable, and magnesium chloride is particularly preferable.
  • Magnesium chloride hexahydrate is preferred.
  • the pH at the time of mixing with the aqueous liquid (B2) or the mixed aqueous liquid (B4) is preferably adjusted to 6 or more and less than 8.
  • an aqueous solution in which the molar ratio of aluminum ion: zinc ion is 1: 2, and the concentrations of aluminum ion and zinc ion are respectively 0.0 lmo 11 or more and 211101 ZL or less is used while stirring.
  • Aluminum and zinc ions can be used in any source.
  • aluminum chloride, aluminum chloride hexahydrate, aluminum sulfate, and aluminum nitrate are preferable as aluminum ion raw materials, and aluminum chloride and aluminum chloride hexahydrate are particularly preferable.
  • aluminum chloride and aluminum chloride hexahydrate are particularly preferable.
  • zinc chloride, zinc nitrate hexahydrate, zinc sulfate, and zinc sulfate heptahydrate are preferable, and zinc chloride is particularly preferable.
  • the metal ion aqueous solution is preferably added at a metal ion concentration of 0.01 mol / L or more and 2 mol 1 / L or less.
  • Metal ion concentration If the degree is lower than this, the amount of water will increase when the required metal is added, and as a result, the concentration of the fluorinated emulsifier will decrease, and the recovery efficiency will decrease. If the metal ion concentration is higher than this range, the metal ion aqueous solution is acidic. Therefore, by adding the aqueous solution, the optimum pH range for locally forming a layered double hydroxide in the step (Y) is obtained.
  • the metal ion is not effectively used for forming the layered double hydroxide.
  • the fluorine-containing emulsifier can be efficiently recovered by adding a metal ion aqueous solution having an appropriate concentration range again.
  • the amount of the metal ion used is such that the trivalent ion is 1 to 10 times the molar amount of the fluorinated emulsifier, and the divalent ion is the fluorinated emulsifier. It is preferable that the molar ratio of the trivalent ion to the divalent ion is 3: 1 to 1: 3 with respect to the molar ratio. The molar ratio of the trivalent ion to the divalent ion is more preferably 1: 1 to 1: 2. If the amount of the metal ion used is less than the above, the recovery of the fluorinated emulsifier is insufficient. Does not increase. Further, excessive use of the metal ions is not preferable from the viewpoint of increasing the load in the final wastewater treatment process.
  • the stirring method is not particularly limited, but a stirring method that does not mechanically destroy the formed layered double hydroxide (C) is preferable.
  • a stirring blade capable of uniformly mixing the whole liquid mixture at a low speed is preferable, and one selected from the group consisting of a full zone blade, a max blend blade and an anchor blade is preferable.
  • G value during stirring at the stirring blade is preferably from 1 ⁇ 3 0 0 s 1, more preferably 5 ⁇ 2 5 0 s _ 1, 1 0 ⁇ 2 0 0 s _ 1 is most preferred.
  • the G value refers to a value derived from the following equation.
  • ⁇ is the stirring power (W)
  • V is the liquid volume (m 3 )
  • X is the liquid viscosity coefficient (P a-s).
  • step (Y) during the mixing with the aqueous metal ion solution, bubbling with an inert gas such as nitrogen gas or argon gas or the like is performed to remove carbon dioxide and / or carbon dioxide present in the system. After expelling the carbonate ions and / or carbon dioxide gas with the gas, it is preferable to seal the reaction vessel. This is because the layered double hydroxide reacts with the carbonate ion and hinders the recovery of the fluorinated emulsifier. Flow rate of the inert gas when carrying out the bubbling 0. I Nm 3 / m 3 ⁇ h ⁇ l O Nm 3 Zm 3 ⁇ h preferably, 0.
  • the step (Y) is preferably performed at a temperature of 10 to 50 ° C. If the temperature is too high or too low, the fixing rate of the fluorine-containing emulsifier by the layered double hydroxide decreases. In particular, if the temperature is too low, the fixation rate is significantly reduced. Therefore, it is preferable to equip the immobilization reactor with a heating device.
  • the layered double hydroxide (C) having the fluorinated emulsifier fixed between the layers obtained in the step (Y) is first separated.
  • the separation method is not particularly limited, and a general solid-liquid separation method can be employed. In particular, it is preferable to use one or more methods selected from the group consisting of filtration, decantation, gravity sedimentation, and centrifugation. The filtration is also preferably performed under pressure. From the viewpoint of facility maintenance and the like, a solid-liquid separation method using a thickener or a screw decanter is most preferable.
  • the separated layered double hydroxide (C) and the fluorine-containing emulsifier are regenerated and recovered.
  • the layered double hydroxide (C) is redissolved with a strong acid such as hydrochloric acid, sulfuric acid, or nitric acid or a mixture of two or more kinds of the strong acids, and contains a precipitate precipitated from the solution.
  • a strong acid such as hydrochloric acid, sulfuric acid, or nitric acid or a mixture of two or more kinds of the strong acids
  • the free acid of the fluorine emulsifier may be extracted with a water-insoluble organic solvent such as a fluorine-based solvent.
  • the method for recovering the fluorinated emulsifier of the present invention not only the fluorinated emulsifier, also, the present invention can be applied to low molecular weight fluorinated carboxylic acids such as trifluoroacetic acid and pentafluoropropanoic acid and / or salts thereof, trifluoromethanesulfonic acid and Z or salts thereof.
  • fluorinated carboxylic acids such as trifluoroacetic acid and pentafluoropropanoic acid and / or salts thereof, trifluoromethanesulfonic acid and Z or salts thereof.
  • the concentration of APFO, perfluorooctanoic acid (hereinafter referred to as PFOA) or sodium perfluorooctanoate is determined by using a high-speed night-time chromatographic gel mass spectrum using a mixed solution of methanol and water as a solvent. It was measured using the method. Species to be detected by this method is per full O Roo Kuta hexanoate (C 7 F 1 5 COO I).
  • the SS component in the coagulated effluent was measured (unit: mass%) by measuring 10 g of the coagulated effluent after coagulating and separating PTFE from the aqueous dispersion of PTFE, using a METTLER TOLEDO Haguchi Gen-type moisture meter HR. — Put in 73, dried at 200 ° C until the mass became constant, and the evaporation residue was used as the SS component.
  • PTFE powder was agglomerated from an aqueous PTFE dispersion produced by emulsion polymerization using APFO as an emulsifier. 10.0 kg of this PTFE powder (moisture content: 48% by mass) was placed in a hot-air circulation oven, and the temperature was gradually increased from 100 ° C to 5 ° C. Heat treated for hours. The displacement of the exhaust gas from the hot-air circulation oven was 4.5 Nm 3 . The entire amount of this exhaust gas was introduced into a spray tower having a diameter of 50 cm and a height of 500 cm. The linear velocity of the gas at this time was about 0.5 mZ seconds.
  • a 0.2 N aqueous solution of sodium hydroxide was added to adjust the pH to 10.0.
  • the liquid temperature was 26 ° C.
  • the glass beaker one 2 L the solution 1 L (AP FO content 0. 49 8 g, 1. 1 6mmo 1) were charged, mixed aqueous solution [A 1 3 + ions magnesium chloride salt aluminum Concentration 0.0 7 51110 1/1 ⁇ 2 + ion 0.15mol ZL] about 77.3mL [A1 3 + Ion total amount 5.8 Ommo and Mg 2 + ion total amount 11.6 mmol] were added dropwise over 2 hours.
  • stirring was continued using an anchor blade so that the G value became 100 s- 1 .
  • a 0.2 N aqueous sodium hydroxide solution was appropriately added dropwise to adjust the pH to 9.8 or more and 10.2 or less.
  • Example 1 the aqueous solution in which APTFE was recovered from exhaust gas during drying and heat treatment of the PPTFE powder was 5001111 ⁇ .
  • the APFO concentration in this mixed aqueous solution was analyzed, it was 323 ppm by mass.
  • a 0.2 N aqueous sodium hydroxide solution was added to adjust the pH to 10.0.
  • the liquid temperature was 26 ° C.
  • PTFE powder was agglomerated from an aqueous PTFE dispersion produced by emulsion polymerization using APFO as an emulsifier.
  • This PTFE powder (10.0 kg, water content: 48% by mass) was placed in a hot air circulation oven, heated at a rate of 100 ° C to 5 ° CZ over time, and then heat-treated at 200 for 1 hour.
  • the displacement of the exhaust gas from the hot-air circulation oven was 4.5 Nm 3 / h.
  • the entire amount of the exhaust gas was introduced into a spray tower having a diameter of 50 cm and a height of 500 cm.
  • the linear velocity of the gas at this time was about 0.5 m / sec.
  • a 0.2 N aqueous sodium hydroxide solution was added to the coagulated wastewater in which the APFO was absorbed to adjust the pH to 10.0.
  • the liquid temperature was 26 ° C.
  • the glass-bi one car 2L, the aqueous solution 1L (APFO content 0. 640 g, 1. 48 mm o 1) were charged, mixed aqueous solution of magnesium chloride and aluminum chloride [A 1 3 + ion concentration 0. 075Mo 1 Bruno, dropwise over Mg 2 + ions 0. 15mo l / L] of 99. 3 m L [a 1 3 + ion amount 7. 4 Ommo 1, Mg 2 + ions total 14. 8mmo 1] for 2 hours did.
  • PTFE powder was agglomerated from a PTFE aqueous dispersion produced by emulsion polymerization using APFO as an emulsifier. 20 kg of this PTFE powder (moisture content: 48% by mass) was placed in a hot air circulation oven, and the temperature was gradually increased from 100 ° C to 5 ° C over time.
  • Heat treatment was performed at 200 ° C for 1 hour.
  • the displacement of the exhaust gas from the hot-air circulation oven was 1 ONm 3 .
  • the entire amount of this exhaust gas was introduced into a packed column having a diameter of 10 cm and a height of 200 cm.
  • the packed tower was filled with 5/8 inch stainless steel pole rings.
  • the linear velocity of the gas at this time was about 0.3 mZ seconds.
  • 70 kg of ion-exchanged water whose pH was adjusted to 10 using potassium hydroxide was circulated at a flow rate of 500 L Zh. Drying of the PTFE powder *
  • the APFO concentration in the alkaline water in the packed tower was analyzed and found to be 495 mass ppm.
  • ⁇ H was adjusted to 10.0 by adding a 0.2 N aqueous sodium hydroxide solution to the APFO-containing aqueous solution.
  • the liquid temperature was 26.
  • the glass beaker one 2 L, the aqueous solution 1L (APFO content 0. 495 g, 1. 16 mm o 1) were charged, mixed aqueous solution of magnesium chloride and aluminum chloride [A1 3 + ion concentration 0.0 75mo 1 / L, Mg 2 + ions 0. 15mo 1 ZL] of about 76. 8 mL [a 1
  • the fluorinated polymer is obtained by emulsion polymerization or aqueous dispersion polymerization in an aqueous medium containing the fluorinated emulsifier.
  • the contained fluorine-containing emulsifier can be efficiently recovered.
  • a fluorinated monomer or a fluorinated monomer and a monomer other than the fluorinated monomer are added to an aqueous medium containing a fluorinated emulsifier.
  • aqueous dispersion of a fluoropolymer obtained by emulsion polymerization or aqueous dispersion polymerization in step (1) which is contained in the wastewater (usually flocculated wastewater) after coagulation and separation of the fluoropolymer by salting out, etc.
  • the emulsifier can also be recovered efficiently.

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  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Treating Waste Gases (AREA)
  • Gas Separation By Absorption (AREA)
  • Removal Of Specific Substances (AREA)

Abstract

L'invention concerne un procédé permettant de récupérer un émulsifiant contenant un fluor. Ledit procédé consiste à mettre en contact un gaz d'échappement produit dans une étape de séchage et/ou de traitement thermique d'un fluoropolymère, obtenu par polymérisation d'une émulsion ou d'une dispersion aqueuse dans un milieu aqueux contenant un fluor, avec une solution aqueuse dont le pH est réglé à 7 ou moins mais en-dessous de 12 comprenant un alcali qui permet d'absorber l'émulsifiant contenant un fluor dans la solution alcaline aqueuse; à former un hydroxyde à deux couches dans la solution aqueuse contenant l'émulsifiant contenant un fluor; à immobiliser l'émulsifiant entre les couches; et à récupérer ledit émulsifiant. Grâce à ce procédé, on peut extraire un émulsifiant contenant un fluor à partir d'un gaz d'échappement produit dans une étape de séchage et/ou de traitement thermique d'un fluoropolymère.
PCT/JP2003/003845 2002-03-28 2003-03-27 Procede de recuperation d'emulsifiant contenant du fluor WO2003082793A1 (fr)

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US7671112B2 (en) 2005-07-15 2010-03-02 3M Innovative Properties Company Method of making fluoropolymer dispersion
US20080015304A1 (en) 2006-07-13 2008-01-17 Klaus Hintzer Aqueous emulsion polymerization process for producing fluoropolymers
US20080264864A1 (en) 2007-04-27 2008-10-30 3M Innovative Properties Company PROCESS FOR REMOVING FLUORINATED EMULSIFIER FROM FLUOROPOLMER DISPERSIONS USING AN ANION-EXCHANGE RESIN AND A pH-DEPENDENT SURFACTANT AND FLUOROPOLYMER DISPERSIONS CONTAINING A pH-DEPENDENT SURFACTANT
WO2012043870A1 (fr) * 2010-10-01 2012-04-05 Daikin Industries, Ltd. Procédé de récupération de tensioactif fluoré
SE541002C2 (en) * 2016-07-06 2019-02-26 Airwatergreen Group Ab Device for continuous water absorption and an air cooler
CN109876628A (zh) * 2019-02-19 2019-06-14 无锡威士德气体净化科技有限公司 一种去除生活垃圾恶臭的复合除臭剂及其制备方法和应用

Citations (2)

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Publication number Priority date Publication date Assignee Title
US5990330A (en) * 1995-03-09 1999-11-23 Dyneon Gmbh Recovery of highly fluorinated carboxylic acids from the gas phase
WO2002010105A1 (fr) * 2000-07-27 2002-02-07 Jemco Inc. Methode de traitement de compose fluore et substance traitee

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5990330A (en) * 1995-03-09 1999-11-23 Dyneon Gmbh Recovery of highly fluorinated carboxylic acids from the gas phase
WO2002010105A1 (fr) * 2000-07-27 2002-02-07 Jemco Inc. Methode de traitement de compose fluore et substance traitee
WO2002010104A1 (fr) * 2000-07-27 2002-02-07 Jemco Inc. Procede de traitement d'un compose fluor

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