EP0846789A1 - Procédé pour modifier la perméabilité de diaphragmes - Google Patents

Procédé pour modifier la perméabilité de diaphragmes Download PDF

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Publication number
EP0846789A1
EP0846789A1 EP97121253A EP97121253A EP0846789A1 EP 0846789 A1 EP0846789 A1 EP 0846789A1 EP 97121253 A EP97121253 A EP 97121253A EP 97121253 A EP97121253 A EP 97121253A EP 0846789 A1 EP0846789 A1 EP 0846789A1
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EP
European Patent Office
Prior art keywords
diaphragm
dispersion
diaphragms
fluorine
containing component
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97121253A
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German (de)
English (en)
Inventor
Holger Dr. Friedrich
Klaus-Dieter Dr. Hoppe
Bernd Dr. Leutner
Dieter Dr. Schläfer
Kurt Hecky
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BASF SE
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BASF SE
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Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Publication of EP0846789A1 publication Critical patent/EP0846789A1/fr
Withdrawn legal-status Critical Current

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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
    • C25B13/00—Diaphragms; Spacing elements
    • 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

Definitions

  • the present invention relates to a method for modifying the Flow resistance of diaphragms, especially plastic diaphragms from chlor-alkali electrolysis.
  • the quality of a diaphragm is determined by its flow resistance or the flow resistance and thus determined by the speed, with which the brine in the cell can flow through the diaphragm.
  • the higher the flow resistance of the diaphragm the less Brine flows through the diaphragm in one time unit and the higher it is Example of chlor-alkali electrolysis the concentration of the sodium hydroxide solution obtained.
  • concentration is not allowed here either get high, otherwise the caustic soda can crystallize and so it procedural difficulties may arise.
  • concentration value considered in the case of chlor-alkali electrolysis is approx. 12 to 13% by weight.
  • DE-A 195 00 871 describes a process for recycling in particular Plastic diaphragms described in which the fibrils or fibers of the Original diaphragms after recycling both have a reduced diameter as well as have a reduced length.
  • the recycled fibers deliver diaphragms whose permeability is greater than that of original diaphragms. It has therefore been suggested that the mash when dropping the Diaphragms are a zirconium oxide with a certain particle size distribution to mix. However, this only leads to partial sealing of the recycled Diaphragms.
  • DE-C 36 29 820 describes a process for producing an asbestos-free Original diaphragms described in which organic polymer fibers, -fibrils or filaments with functional groups are added to to support the desired permeability properties of the diaphragm. This increases the permeability of the diaphragm.
  • DE-C 41 43 172 describes a process for producing chlorine and Alkali hydroxide described. To achieve the desired permeability of the diaphragm and the current yield becomes sufficient mineral clay added.
  • DE-A 41 43 173 describes a liquid-permeable diaphragm for Chlor-alkali electrolysis cells described, which is made of fiber material with at least one deposited on the anode side, by cement bonding bonded top layer made of particulate, inorganic, refractory Material. In the spaces between the fiber matrix of the diaphragm can Particulate zirconium oxide can also be incorporated.
  • EP-B 0 412 917 describes a plastic diaphragm and its manufacturing process and the connection of such a diaphragm with described a cathode element.
  • WO 97/05300 describes a method for reducing permeability of a diaphragm in which an amphoteric soluble in the anolyte Material like an aluminum compound, the anolyte of a chlor-alkali diaphragm cell is added when starting the cell.
  • an amphoteric soluble in the anolyte Material like an aluminum compound
  • WO 93/16217 contains diaphragms for electrolysis cells and processes described for their manufacture.
  • the object is achieved by a method for modifying the flow resistance of a diaphragm based on a fiber material, in which the diaphragm is treated during or after production with a dispersion containing or containing fluorine and optionally with a solution containing a precursor substance of ZrO 2 .
  • the treatment can be carried out, for example, by dipping or by running an aqueous solution containing the dispersion which has a fluorine-containing component through the diaphragm before the current (electrolysis) is switched on, the diaphragm being flowed through from the anode side to the cathode side .
  • the preferably recycled diaphragm can be sealed and the flow resistance of the diaphragm can be increased.
  • the average pore diameter in the diaphragm made from recycled fibers is more than 1 ⁇ m, often even 6 to 20 ⁇ m, and it was therefore to be assumed that the dispersion particles of a fluorine-containing dispersion pass through the diaphragm would.
  • the flow resistance of both the original diaphragm and particularly preferably the recycled diaphragm can thus be set more precisely, in particular increased.
  • the precursor substance of ZrO 2 can in particular be ZrOCl 2 , Zr (OR) 4 , where R is a C 1-12 alkyl radical, and / or ZrCl 4 .
  • the fluorine-containing component Dispersion when restoring the diaphragm from fibers in particular the mash is added.
  • the shredded and washed fibers into one Mash processed preferably from vacuum deposition Diaphragms are generated.
  • the mash is preferred an aqueous slurry of fibers containing a thickener, Sodium chloride, sodium hydroxide solution, bacteriocides, various surfactants and defoamers can contain.
  • This mash can preferably contain fluorine Dispersion can be added with stirring. That through vacuum deposition obtained diaphragms have diaphragms that do not contain fluorine Dispersion were produced, a significantly reduced permeability on.
  • the diaphragm is treated during the electrolysis, preferably a chlor-alkali electrolysis.
  • the flow resistance of a diaphragm can thus also be set in situ . It is particularly preferably also possible to subsequently adjust the flow resistance of a diaphragm that has already been treated with fluorine-containing dispersion during the production or the recycling step, in particular also during the electrolysis.
  • the dispersion is preferably diluted with an aqueous medium and the resulting dispersion or the zirconium-containing solution is added to the diaphragm so that it can, for example, run slowly. It is particularly preferred to treat the diaphragm with the dispersion or the zirconium-containing solution during the electrolysis, the dispersion or solution being added to the brine feed to the cell or to the anolyte.
  • the brine treated in this way is preferably pressed through the diaphragm during the electrolysis, it being possible for the flow rate to be set to the desired value, preferably reduced, within a short time, ie from a few minutes to several hours.
  • the dispersion preferably contains a fluoropolymer as the fluorine-containing component, i.e. an organic fluorine-containing polymer, as particularly preferred PVDF (polyvinylidene difluoride), PFA (perfluoroalkoxy polymers) or polychlorotrifluoroethylene, particularly preferably PTFE (polytetrafluoroethylene).
  • a fluoropolymer as the fluorine-containing component
  • an organic fluorine-containing polymer as particularly preferred PVDF (polyvinylidene difluoride), PFA (perfluoroalkoxy polymers) or polychlorotrifluoroethylene, particularly preferably PTFE (polytetrafluoroethylene).
  • PTFE polytetrafluoroethylene
  • the Solids of the fluorine-containing component of the dispersion have a size distribution with maxima in the range from 0.1 to 0.5, preferably 0.15 to 0.4, in particular preferably from 0.2 to 0.3 ⁇ m.
  • Dispersions with solid particles Such diameters have so far appeared for the sealing of medium-sized ones Pore diameters of the recycled diaphragms in the range from 6 to 20 ⁇ m as not suitable. It was assumed that these dispersion particles were the diaphragm would run through. However, it was found that such dispersions can be used.
  • the pore diameter distribution in Original diaphragm can have maxima at 0.2 to 0.5 ⁇ m and a smaller one Have a maximum at 8 to 20 ⁇ m.
  • diaphragms made from recycled Material can also have a maximum pore diameter of 0.2 up to 0.5 ⁇ m, but mainly such a diaphragm is Pores characterized with diameters that have two maxima - for example at 10 to 40 ⁇ m and at 100 to 300 ⁇ m - have. These bigger ones Pores are mainly used in comparison to the original diaphragms greater permeability of diaphragms made from recycled material blamed. It has been found that with particles that have a Have a diameter of less than 1 ⁇ m, sealing the diaphragm can be done.
  • aqueous solution before use preferably sodium chloride solution, diluted. This makes it possible to adjust the flow and mixing behavior of the dispersion to the conditions of the adapting the treating diaphragm.
  • the dispersion contains 0.1 to 10% by weight, preferably 3 to 6% by weight, of one preferably non-ionic surfactants.
  • the stability of the Dispersion can be adjusted.
  • the diaphragm can also be in one additional step (again) with a surfactant to remove the Readjust the surface behavior of the diaphragm again. Furthermore this can increase the wettability.
  • the dispersion has a pH of 4 to 11, particularly preferably 8 to 10 on.
  • the amount is of the solids content of the dispersion used, in particular the amount of PTFE used based on the fiber material of the diaphragm 0.1 to 30% by weight, preferably 0.5 to 10% by weight and particularly preferably 3 to 7% by weight.
  • the percentages by weight relate to weight of pure solids or PTFE per fiber weight.
  • the amount of solids content of the dispersion used in particular the amount of PTFE used, based on the diaphragm area, 30 to 500 g / m2 diaphragm area, preferably 50 to 300 g / qm, particularly preferably 100 to 200 g / qm.
  • the object of the invention is particularly with a diaphragm solved that manufactured or treated by the inventive method has been.
  • FIG. 1 shows the flow D (in l / m 2 h) of a brine (300 g / l NaCl) through a diaphragm before and after the treatment with 60% PTFE dispersion against the time Z (in hours). At the times marked with arrows, 42 g / m 2 of PTFE dispersion were added.
  • Fig. 2 is the flow (D in l / m 2 h) of a brine (300g / l NaCl) through a recycling diaphragm depending on the time (Z in hours) and the addition of PTFE dispersion (at the times marked with arrows twice 42g / m 2 and then twice 84g / m 2 dispersion).
  • diaphragms For the production of diaphragms, one obtained according to DE-A 195 00 871 moist fiber material with a solids content of 76.2%.
  • the mash solution also used is obtained by 12.5 kg Water with 26.25 g of thickener based on a polysaccharide, 26.25 g Proxel® GXL (ICI, bacteriocide with active ingredient 1,2-benzisothiazolin-3-one) and 3.1 g of the DC10010A silicone defoamer (ex Dow Corning) and homogenized with the Ultraturrax.
  • An Fe expanded metal cathode grid with a fine-mesh nylon mesh is clamped in a small storage device.
  • the homogenized fiber mix described above is then poured on and run through the nylon net for 30 minutes without negative pressure.
  • the amount of mash solution that has passed through is 170-210 ml.
  • the depositing device is subjected to a negative pressure by means of a membrane pump. Time in min Pressure in mbar 0 normal 1 980 5 940 9 850 13 850 17th 740 20th 640 25th 530 30th 500 35 200 40 200
  • the diaphragm After sucking through the mash solution, the diaphragm remains for 90 Min. On the suction. After 140 minutes, the vacuum applied is approx. 310 mbar.
  • the diaphragm was then treated with 4% zonyl solution for 30 minutes.
  • a sodium chloride solution 300 g / l
  • the flow of the brine solution through the diaphragm was 16 l / m 2 h after 1 h and 23 l / m 2 h after 10 h.
  • Example 2 A test diaphragm was produced according to Example 1 and the Flow determined. In contrast to Example 1, however, only 1 g PTFE dispersion used.
  • a test diaphragm was made according to Example 1 and the flow rate was determined. No PTFE dispersion was used in the production of the fiber mash, but the diaphragm was post-treated with PTFE dispersion. For this purpose, 2 x 42 g PTFE dispersion Hostaflon® TFX5050 per m 2 were added to the inlet of the brine during the measurement of the test diaphragm. The diaphragm, which had a flow rate of approx. 85 l / h * m 2 before the treatment, then had a permeability of approx. 55 l / h * m 2 . This test course is illustrated in FIG. 1. The time is shown on the X axis and the flow rate on the Y axis. It can be clearly seen that when the PTFE dispersion is added, the passage decreases.
  • Example 1 an electrolytic cell from De Nora with an electrode area of 700 cm 2 was coated with a diaphragm. For this purpose, the amounts of coating material used were increased in accordance with the electrode area. After starting the electrolysis, the cell had a brine flow of 5.5 l / h. After treatment with 2 times 15 g of PTFE dispersion Hostaflon® TFX 5050, the flow rate decreased to 3.8 l / h.
  • the method according to the invention for modifying the flow resistance a diaphragm is more economical and reliable than known ones Method. With it, the flow resistance can also be produced can be set to a desired range.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
EP97121253A 1996-12-04 1997-12-03 Procédé pour modifier la perméabilité de diaphragmes Withdrawn EP0846789A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19650316 1996-12-04
DE19650316A DE19650316A1 (de) 1996-12-04 1996-12-04 Verfahren zur Modifikation des Durchflußwiderstandes von Diaphragmen

Publications (1)

Publication Number Publication Date
EP0846789A1 true EP0846789A1 (fr) 1998-06-10

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ID=7813637

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97121253A Withdrawn EP0846789A1 (fr) 1996-12-04 1997-12-03 Procédé pour modifier la perméabilité de diaphragmes

Country Status (5)

Country Link
US (1) US5919348A (fr)
EP (1) EP0846789A1 (fr)
JP (1) JPH10273792A (fr)
DE (1) DE19650316A1 (fr)
NO (1) NO975601L (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6059944A (en) * 1998-07-29 2000-05-09 Ppg Industries Ohio, Inc. Diaphragm for electrolytic cell
EP2417854A1 (fr) * 2010-08-09 2012-02-15 Rohm and Haas Company Compositions contenant du 1,2-benzisothiazolin-3-one et un polysaccharide
CN103548845A (zh) * 2009-07-30 2014-02-05 罗门哈斯公司 协同杀微生物组合物

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19746404A1 (de) * 1997-10-21 1999-04-22 Basf Ag Verfahren zur Herstellung von Kompositfasern und Disphragmen
US7329332B2 (en) * 2004-08-25 2008-02-12 Ppg Industries Ohio, Inc. Diaphragm for electrolytic cell
US7618527B2 (en) * 2005-08-31 2009-11-17 Ppg Industries Ohio, Inc. Method of operating a diaphragm electrolytic cell
WO2008030216A1 (fr) * 2006-09-07 2008-03-13 Ppg Industries Ohio, Inc. Procede d’utilisation d’une pile electrolytique a diaphragme
US8460536B2 (en) * 2006-01-19 2013-06-11 Eagle Controlled 2 Ohio Spinco, Inc. Diaphragm for electrolytic cell
ITMI20072271A1 (it) 2007-12-04 2009-06-05 Industrie De Nora Spa Separatore per celle elettrolitiche cloro-alcali e metodo per la sua fabbricazione
US8784620B2 (en) * 2010-05-13 2014-07-22 Axiall Ohio, Inc. Method of operating a diaphragm electrolytic cell
WO2019055801A1 (fr) * 2017-09-15 2019-03-21 Dow Global Technologies Llc Modification temporaire de la perméabilité d'un diaphragme perméable aux 'électrolytes
WO2019055815A1 (fr) * 2017-09-15 2019-03-21 Dow Global Technologies Llc Diaphragme perméable à l'électrolyte
CN113659225B (zh) * 2021-07-20 2024-07-30 河南巨峰环保科技有限公司 锂电池隔膜废料的回收利用方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0412917A1 (fr) * 1989-08-10 1991-02-13 Rhone-Poulenc Chimie Diaphragme, association d'un tel diaphragme à un élément cathodique et leur procédé d'obtention
US5266350A (en) * 1992-07-14 1993-11-30 The Dow Chemical Company Processes and materials for treatment and repair of electrolytic cell separators

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2938069A1 (de) * 1979-09-20 1981-04-02 Siemens AG, 1000 Berlin und 8000 München Asbestdiaphragmen fuer elektrochemische zellen und deren herstellung
US4666573A (en) * 1985-09-05 1987-05-19 Ppg Industries, Inc. Synthetic diaphragm and process of use thereof
US4680101A (en) * 1986-11-04 1987-07-14 Ppg Industries, Inc. Electrolyte permeable diaphragm including a polymeric metal oxide
US5188712A (en) * 1991-01-03 1993-02-23 Ppg Industries, Inc. Diaphragm for use in chlor-alkali cells
CA2057826C (fr) * 1991-01-03 1998-09-01 Donald W. Dubois Methode d'utilisation des cellules a chloralcali
US7018809B1 (en) * 1991-09-19 2006-03-28 Genentech, Inc. Expression of functional antibody fragments
FR2703075B1 (fr) * 1993-03-26 1995-06-16 Rhone Poulenc Chimie Procede de preparation de diaphragme microporeux.
DE19500871A1 (de) * 1995-01-13 1996-07-18 Basf Ag Verfahren zum Recyclen von Diaphragmen
US5630930A (en) * 1995-07-26 1997-05-20 Ppg Industries, Inc. Method for starting a chlor-alkali diaphragm cell

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0412917A1 (fr) * 1989-08-10 1991-02-13 Rhone-Poulenc Chimie Diaphragme, association d'un tel diaphragme à un élément cathodique et leur procédé d'obtention
US5266350A (en) * 1992-07-14 1993-11-30 The Dow Chemical Company Processes and materials for treatment and repair of electrolytic cell separators

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6059944A (en) * 1998-07-29 2000-05-09 Ppg Industries Ohio, Inc. Diaphragm for electrolytic cell
CN103548845A (zh) * 2009-07-30 2014-02-05 罗门哈斯公司 协同杀微生物组合物
EP2417854A1 (fr) * 2010-08-09 2012-02-15 Rohm and Haas Company Compositions contenant du 1,2-benzisothiazolin-3-one et un polysaccharide
CN102379294A (zh) * 2010-08-09 2012-03-21 陶氏环球技术有限公司 包含1,2-苯并异噻唑啉-3-酮的组合物

Also Published As

Publication number Publication date
NO975601L (no) 1998-06-05
US5919348A (en) 1999-07-06
NO975601D0 (no) 1997-12-03
DE19650316A1 (de) 1998-06-10
JPH10273792A (ja) 1998-10-13

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