[go: up one dir, main page]

EP0745701B1 - Procédé de régénération de diaphragmes en matière synthétiques - Google Patents

Procédé de régénération de diaphragmes en matière synthétiques Download PDF

Info

Publication number
EP0745701B1
EP0745701B1 EP96108246A EP96108246A EP0745701B1 EP 0745701 B1 EP0745701 B1 EP 0745701B1 EP 96108246 A EP96108246 A EP 96108246A EP 96108246 A EP96108246 A EP 96108246A EP 0745701 B1 EP0745701 B1 EP 0745701B1
Authority
EP
European Patent Office
Prior art keywords
weight
diaphragm
corrosion inhibitor
mineral acid
acid solution
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.)
Expired - Lifetime
Application number
EP96108246A
Other languages
German (de)
English (en)
Other versions
EP0745701A1 (fr
Inventor
Rudi Dr. Kröner
Bernd Dr. Leutner
Hans-Michael Dr. Schneider
Holger Dr. Friedrich
Kurt Hecky
Dieter Dr. Schläfer
Wolfgang Dr. Steiner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Original Assignee
BASF SE
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Publication of EP0745701A1 publication Critical patent/EP0745701A1/fr
Application granted granted Critical
Publication of EP0745701B1 publication Critical patent/EP0745701B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • 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 the regeneration of Plastic diaphragms, especially for the regeneration of plastic diaphragms from chlor-alkali electrolysis.
  • the diaphragm process uses electrolysis cells used that use an iron cathode grid on which the Diaphragm material e.g. has been applied by vacuum deposition.
  • Dimensionally stable anodes are generally used as anode today, which are, for example, expanded metal grids made of titanium acts that are coated with ruthenium oxide / titanium oxide. After installation the anodes are expanded into the cell by the distance between the anode and cathode and thus the ohmic voltage drop as low as possible to keep.
  • the diaphragm process uses diaphragms made of different materials, such as asbestos. More recently, plastic diaphragms have also been used, which are produced by vacuum deposition of a fiber material and subsequent sintering.
  • the fiber material can consist, for example, of PTFE fibers with embedded and adhering ZrO 2 particles. Examples of such a fiber material are Polyramix® fibers (Oxytech) and Tephram® fibers (PPG Industries, Inc.).
  • plastic diaphragms can be operated much longer. While an asbestos diaphragm typically has a service life of approximately 4,000 to 10,000 operating hours and is then replaced, plastic diaphragms can be used over a period of approximately 17,000 to 26,000 operating hours.
  • Asbestos diaphragms are due to the shorter operating time not to the growths as with the plastic diaphragms.
  • the superficial deposits on asbestos diaphragms for example in US 1,309,214 proposed using the asbestos diaphragms wash diluted lactic acid. This allows gelatinous deposits to be removed remove from magnesium and / or calcium hydroxide, which the Clog the diaphragm without corroding the iron parts or iron cathode, the iron oxide penetrations in plastic diaphragms can be but not in this way.
  • DE 19 56 291 proposes clogging of diaphragms by rinsing of the diaphragm with hydroxypolycarboxylic acids, such as citric acid, gluconic acid etc. to remove.
  • This method is also suitable, superficial To partially remove deposits from iron oxides, removing them of iron oxide penetration in plastic diaphragms is due to this Way not possible.
  • Japanese patent application JP 60077985 in which a method for Cleaning of electrolytic cells of the diaphragm type, in particular for Production of hydrogen from alkalis is used with mixtures described from acids and surfactants is only for cleaning a dismantled Asbestos diaphragms can be used because the corrosion of the iron and titanium parts cannot be avoided.
  • German Offenlegungsschrift 15 67 962 describes a method for Regeneration of an asbestos diaphragm, in order to protect the iron parts a corrosion inhibitor is used. Also leave after this procedure only superficial deposits become detached during growth of the diaphragm cannot be removed. Because asbestos as a material is not stable under strongly acidic conditions are also those in the published patent application proposed corrosion inhibitors to protect the cathode not sufficient when regenerating a plastic diaphragm. In addition, this method cannot prevent titanium corrosion will.
  • the non-prepublished, priority EP-A-0 694 632 relates to the workup of diaphragms from electrolysis cells.
  • the arrangement of cathode and Treated the diaphragm with a solution without separating the cathode from the diaphragm, the at least about 3% by weight hydrochloric acid and at least about 0.1% by volume one Contains corrosion inhibitor.
  • Treatment is done by dipping the assembly into this medium and allowing the medium to flow through the diaphragm. After Treatment is removed from the solution with an aqueous solution Medium washed, baked at elevated temperature and after treatment with a Wetting agent dried.
  • the object of the present invention is therefore a method for regeneration of plastic diaphragms, where deposits and / or growth on or in the plastic diaphragm economically can be removed, especially without iron and / or Titanium parts corrode significantly and without residues that are difficult to dispose of arise.
  • This task is accomplished through a regeneration process Plastic diaphragms solved, in which a mineral acid solution containing sodium chloride up to the saturation concentration with a Corrosion inhibitor is added, and the mixture thus obtained at a Temperature from 0 to 110 ° C, preferably 30 to 110 ° C, more preferably 40 to 80 ° C, in particular 50 to 70 ° C, about 0.1 to 84 hours, preferably 1 to 72 hours, in particular 2 to 24 hours through which the plastic diaphragm is passed.
  • this method provides a possibility, too to remove stubborn, poorly soluble and streaky iron deposits, as well as the regeneration of the plastic diaphragm in to be able to perform in situ without having to remove the diaphragm, because adequate protection of the iron and titanium components can be achieved. Furthermore is not an expansion of the diaphragms in the preferred cell construction possible without destroying the diaphragms. Plastic diaphragms are preferred therefore regenerated in the cell. The regeneration in the Electrolysis cell saves time, costs and labor.
  • a method is preferably provided in which the mineral acid solution in a concentration of 0.3 to 20% by weight, in particular 2 to 10 % By weight is used.
  • the use of a is particularly preferred Acid, at least partially, preferably exclusively from hydrochloric acid exists as a mineral acid.
  • hydrochloric acid prevents that foreign ions enter the cell, which can then be Rinsing would have to be removed again.
  • another mineral acid for example Sulfuric acid, suitable.
  • the mineral acid solution contains bis to 250 g / l sodium chloride.
  • the cleaning effect of this mixture increases. So it is e.g. when adding NaCl possible to reduce the concentration of hydrochloric acid (e.g. by 9% to 2%), the solution still having a sufficient cleaning effect owns.
  • the corrosion inhibitor in another preferred method of the present invention is in the mixture of the mineral acid solution with the corrosion inhibitor 0.005 to 5% by weight, preferably 0.05 to 0.5% by weight, of corrosion inhibitor provided, the percentages by weight refer to the mixture of the mineral acid solution refer to the corrosion inhibitor as 100 wt .-%. This dosage of the corrosion inhibitor leads to protection of the iron parts in the Electrolytic cell.
  • a corrosion inhibitor that contains at least one alkinol.
  • P refers a corrosion inhibitor can also be used, which at least contains an alkinol and preferably with 1 to 25 wt .-% of an amine and / or 0.1 to 3 wt .-% of a surfactant is added, the weight percentages refer to the corrosion inhibitor as 100% by weight.
  • Alkynols can, for example, alkynediols, such as butynediol, 3-hexyne-2,5-diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,5-dimethyl-3-hexyne-2,5-diol, or else Propargyl alcohol or hexinol (3-hexin-2-ol) or ethinylcyclohexanol.
  • alkynediols such as butynediol, 3-hexyne-2,5-diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,5-dimethyl-3-hexyne-2,5-diol, or else Propargyl alcohol or hexinol (3-hexin-2-ol) or ethinylcyclohexanol.
  • alkynols can be amines, such as hexamethylenetetramine, Ethylhexylamine, diethylhexylamine or other primary, secondary or tertiary Amines can be added.
  • the alkynols act as a monomer for the formation of a corrosion-inhibiting coating on the iron parts, to be protected.
  • a surfactant used which contains a quaternary ammonium compound.
  • Organic ammonium compounds with quaternary nitrogen atoms for example quaternary ammonium compounds with in particular long alkyl chains, such as for example distearyldimethylammonium chloride (DSDMA), Protectol KLC 80® or Protectol KLC 50® (BASF) or Pluradyne CI 1066® (BASF Corp.).
  • Particularly preferred mixtures of alkynols with amines and / or quaternary ammonium compounds comprise about 98% butynediol and 2% hexamethylenetetramine or, for example, about 97.8% butynediol plus about 2% hexamethylenetetramine plus about 0.2% Protectol KLC 50®.
  • the mineral acid solution contains about 500 to 5000 ppm copper or iron salts.
  • Water-soluble Fe III or Cu II salts are preferably added to the mixture of the mineral acid solution and the corrosion inhibitor. This can be achieved, for example, by additionally adding, for example, iron chloride to the mixture of the mineral acid solution with the corrosion inhibitor, or by pumping the mixture of the mineral acid solution with the corrosion inhibitor through the diaphragm in a circle.
  • the iron-containing deposits detached from the diaphragm thereby provide Fe 3+ compounds, which then act as a corrosion inhibitor with respect to the titanium, of which the anodes in particular have larger proportions in uncoated form.
  • Another advantageous method of the present invention provides that the diaphragm additionally with water and / or a sodium chloride solution rinsed, in particular rinsed.
  • water used it is preferably pure water.
  • a sodium chloride solution is advantageously used for this rinse used, because in this case the freshener is filled later Brine into the cell does not pose the risk of uncontrolled dilution There is residual water.
  • the cell is filled with fresh brine anyway.
  • alkynols also alkyne monools, in particular propargyl alcohol or Ethinylcyclohexanol, with an alkinol preferably in one concentration greater than 30% by weight, typically in a concentration greater than 80 % By weight is used.
  • the percentage by weight relates on the total alkynols used as 100% by weight.
  • These corrosion inhibitors are more effective in preventing corrosion of iron. They can preferably be used wherever cells are used be in which anodes are provided, which are completely with a Ruthenium-titanium oxide layer are coated. In addition, in this case the addition of iron salts can be dispensed with.
  • Effective corrosion inhibitors are mixtures containing alkyne monools, for example propargyl alcohol or ethinylcyclohexanol, as the main component. These corrosion inhibitors are particularly suitable for use in mixtures that are not dissolved Have iron salts. The mixture of mineral acid solution with the In this case, the corrosion inhibitor should only be used once.
  • a preferred mixture for inhibiting iron corrosion includes, for example a mixture of about 2% Protectol KLC 80®, about 1% ethinylcyclohexanol, about 8% ethylhexylamine or diethylhexylamine, and about 89% Propargyl alcohol.
  • Another advantageous mixture comprises about 2% Pluradyne CI 1066® and about 98% propargyl alcohol.
  • the mixture through an electrolytic cell without prior removal of Diaphragm and electrode conducted. So in this way it is possible that To regenerate the diaphragm without having to remove the diaphragm.
  • Such an in-situ cleaning of the diaphragm saves time, costs and Workload. A complex removal of the diaphragm from the cell and it is therefore no longer necessary to remove the diaphragm material.
  • an advantageous method according to the present invention be provided for the regeneration of plastic diaphragms, a process as described above several times in succession or at least two procedures as described above are used in succession will.
  • this procedure in a row you can for example the diaphragms with different mixtures of mineral acid solutions with different corrosion inhibitors at different Temperatures applied consecutively for different lengths of time the advantages of the individual process parameters can be combined so that for the present impurity optimal combination of individual processes and process parameters is provided.
  • the individual processes or process steps can also by rinsing the diaphragm with a rinsing solution, in particular with pure water or a sodium chloride solution, separated from each other will.
  • a chlor-alkali cell e.g. a monopolar cell from Diamond Shamrock
  • a high hydrogen concentration > 4 vol.%
  • an 8% hydrochloric acid the 0.2 wt .-% Korantin BH® (corrosion inhibitor from BASF AG based on butynediol and hexamethylenetetramine) contains, preheated to 40 ° C and at the Pumped anode side into the cell.
  • solution was pumped in further and removed on the cathode side and returned to the reservoir. This process took 24 hours continued, keeping the temperature of the hydrochloric acid at 50 ° C.
  • a cell in the chlor-alkali electrolysis was switched off and the solution therein was drained off.
  • the diaphragm was then rinsed for 2 hours at 70 ° C. with an aqueous solution of approximately 2% hydrochloric acid, approximately 250 g / l sodium chloride, approximately 0.5% Korantin BH and approximately 0.1% Fe 3+ ions.
  • the diaphragm was then rinsed with pure water for about an hour.
  • the weight loss of the iron cathode was between 0.5 and 1.5% by weight, and the titanium corrosion was less than 0.02% weight loss.
  • the ferrous deposits were completely, i.e. over 98% from which Diaphragm removed.
  • the solution contained therein was drained from a switched off chlor-alkali electrolysis cell.
  • the diaphragm was then rinsed with an aqueous solution containing about 8% hydrochloric acid, 0.5% Korantin BH® and about 0.1% Fe 3+ ions at 70 ° C for about 2 hours.
  • the diaphragm was rinsed with an aqueous solution containing about 8% hydrochloric acid, about 0.5% Korantin BH® and about 0.1% Fe 3+ ions at 50 ° C for 24 hours.
  • the diaphragm was then rinsed with pure water for about an hour.
  • the weight loss of the iron cathode was between 1 and 2% by weight and the titanium corrosion was less than 0.02% weight loss.
  • the ferruginous Storage was complete, i.e. over 98% from which Diaphragm removed.
  • the present invention thus provides a method for regeneration been provided by plastic diaphragms that not only capable growth of iron deposits in plastic diaphragms is economical to remove without corroding the iron and / or titanium parts, it also avoids residues that are difficult to dispose of, that could pollute the environment.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Claims (14)

  1. Procédé pour la régénération de diaphragmes en matière plastique, caractérisé par le fait qu'une solution d'acide minéral, qui contient du chlorure de sodium jusqu'à la concentration de saturation, est additionnée d'un inhibiteur de corrosion et le mélange ainsi obtenu est envoyé à travers le diaphragme en matière plastique à une température de 0 à 110°C pendant 0,1 à 84 heures.
  2. Procédé selon la revendication 1, caractérisé par le fait que la solution d'acide minéral est introduite à une concentration de 0,3 à 20 % en poids.
  3. Procédé selon la revendication 1 ou 2, caractérisé par le fait qu'on emploie comme acide minéral un acide qui consiste au moins pour partie en de l'acide chlorhydrique.
  4. Procédé selon l'une quelconque des revendications 1 à 3, caractérisé par le fait que la solution d'acide minéral contient jusqu'à 250 g/l de chlorure de sodium.
  5. Procédé selon l'une quelconque des revendications 1 à 4, caractérisé par le fait que, dans le mélange de la solution d'acide minéral avec l'inhibiteur de corrosion, il est prévu 0,005 à 5 % en poids d'inhibiteur de corrosion, les indications de pourcentage en poids se rapportant au mélange de la solution d'acide minéral avec l'inhibiteur de corrosion qui représente 100 %.
  6. Procédé selon l'une quelconque des revendications 1 à 5, caractérisé par le fait qu'on emploie un inhibiteur de corrosion qui contient au moins un alcynol.
  7. Procédé selon la revendication 6, caractérisé par le fait qu'on emploie un inhibiteur de corrosion qui contient un alcyne-diol et est additionné de 1 à 25 % en poids d'une amine et/ou de 0,1 à 3 % en poids d'un agent de surface, les indications de pourcentage en poids se rapportant à l'inhibiteur de corrosion qui représente 100 %.
  8. Procédé selon la revendication 7, caractérisé par le fait qu'il s'agit, en ce qui concerne les amines, d'amines du groupe de l'hexaméthylènetétramine, de l'éthylhexylamine ou de la diéthylhexylamine.
  9. Procédé selon l'une quelconque des revendications 6 à 8, caractérisé par le fait qu'au moins un agent de surface contient un sel d'ammonium quaternaire.
  10. Procédé selon l'une quelconque des revendications 1 à 9, caractérisé par le fait que la solution d'acide minéral contient environ 500 à 5000 ppm de composés du cuivre et/ou du fer.
  11. Procédé selon l'une quelconque des revendications 1 à 10, caractérisé par le fait que le diaphragme est en outre rincé avec de l'eau et/ou une solution de chlorure de sodium.
  12. Procédé selon l'une quelconque des revendications 1 à 11, caractérisé par le fait que les alcynols contiennent également des alcyne-monools en une concentration supérieure à 30 % en poids, les indications de pourcentage en poids se rapportant à l'ensemble des alcynols employés qui représente 100 %.
  13. Procédé selon l'une quelconque des revendications précédentes, caractérisé par le fait que le mélange est envoyé à travers une cellule d'électrolyse sans séparation préalable du diaphragme et de l'électrode.
  14. Procédé pour la régénération de diaphragmes en matière plastique, caractérisé par le fait qu'un procédé selon l'une quelconque des revendications précédentes est mis en oeuvre plusieurs fois consécutivement ou au moins deux procédés selon l'une quelconque des revendications précédentes sont mis en oeuvre successivement.
EP96108246A 1995-05-31 1996-05-23 Procédé de régénération de diaphragmes en matière synthétiques Expired - Lifetime EP0745701B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19519921A DE19519921A1 (de) 1995-05-31 1995-05-31 Verfahren zur Regenerierung von Kunststoffdiaphragmen
DE19519921 1995-05-31

Publications (2)

Publication Number Publication Date
EP0745701A1 EP0745701A1 (fr) 1996-12-04
EP0745701B1 true EP0745701B1 (fr) 1998-12-09

Family

ID=7763296

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96108246A Expired - Lifetime EP0745701B1 (fr) 1995-05-31 1996-05-23 Procédé de régénération de diaphragmes en matière synthétiques

Country Status (6)

Country Link
US (1) US5755951A (fr)
EP (1) EP0745701B1 (fr)
CN (1) CN1077609C (fr)
DE (2) DE19519921A1 (fr)
NO (1) NO962216L (fr)
PL (1) PL314547A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7255798B2 (en) * 2004-03-26 2007-08-14 Ion Power, Inc. Recycling of used perfluorosulfonic acid membranes
ITMI20131521A1 (it) * 2013-09-16 2015-03-17 Industrie De Nora Spa Cella elettrolitica per produzione di soluzioni ossidanti
CN111403838B (zh) * 2019-12-23 2023-04-25 余姚市鑫和电池材料有限公司 一种退役动力锂电池隔膜纸回收再利用方法

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1309214A (en) * 1919-07-08 Hugh k
GB1468355A (en) * 1973-07-18 1977-03-23 Ici Ltd Making porous diaphragms in electrolytic cells
US3467586A (en) * 1965-04-12 1969-09-16 Hooker Chemical Corp Rejuvenation of diaphragms for chlor-alkali cells
US3630863A (en) * 1968-11-13 1971-12-28 Ppg Industries Inc Cell diaphragm treatment
US3988223A (en) * 1975-10-28 1976-10-26 Basf Wyandotte Corporation Unplugging of electrolysis diaphragms
SU739261A2 (ru) * 1977-05-23 1980-06-05 Кишиневский политехнический институт им.С.Лазо Вихревой усилитель
US4174269A (en) * 1978-06-21 1979-11-13 Ppg Industries, Inc. Method of treating electrodes
SU808561A1 (ru) * 1978-09-01 1981-02-28 Предприятие П/Я В-2287 Способ промывки диафрагмы
US4204921A (en) * 1979-03-19 1980-05-27 Basf Wyandotte Corporation Method for rejuvenating chlor-alkali cells
US4381230A (en) * 1981-06-22 1983-04-26 The Dow Chemical Company Operation and regeneration of permselective ion-exchange membranes in brine electrolysis cells
JPS6077985A (ja) * 1983-10-06 1985-05-02 Kao Corp 電解槽の洗浄方法および洗浄薬剤
US5133843A (en) * 1990-09-10 1992-07-28 The Dow Chemical Company Method for the recovery of metals from the membrane of electrochemical cells
US5498321A (en) * 1994-07-28 1996-03-12 Oxytech Systems, Inc. Electrolysis cell diaphragm reclamation

Also Published As

Publication number Publication date
US5755951A (en) 1998-05-26
EP0745701A1 (fr) 1996-12-04
DE59600938D1 (de) 1999-01-21
PL314547A1 (en) 1996-12-09
NO962216L (no) 1996-12-02
CN1147566A (zh) 1997-04-16
NO962216D0 (no) 1996-05-30
DE19519921A1 (de) 1996-12-05
CN1077609C (zh) 2002-01-09

Similar Documents

Publication Publication Date Title
DE2818601C2 (fr)
DE102007003554A1 (de) Verfahren zur Leistungsverbesserung von Nickelelektroden
EP1581673A2 (fr) Anode pour electrodeposition
DE2321417A1 (de) Verfahren zur elektrolyse und elektrolytische zelle zu dessen durchfuehrung
DE3318598A1 (de) Bad und verfahren fuer die elektrolytische entfernung von ueberzuegen aus kupfer, kupferlegierung oder chrom von einem eisenhaltigen grundmetall
DE3326982A1 (de) Waessriger saurer chrom(iii)-elektrolyt und verfahren zur verbesserung der toleranz waessriger saurer chrom(iii)-elektrolyte gegenueber der anwesenheit schaedlicher verunreinigender metallionen
EP0745701B1 (fr) Procédé de régénération de diaphragmes en matière synthétiques
DE4232958C1 (fr)
DE3307834A1 (de) Verfahren zur elektrolytischen entfernung von ueberzuegen aus nickel oder nickel-eisen-legierungen von grundmetallen aus kupfer oder kupferlegierungen
DE60125763T2 (de) Aktivierung einer kathode
DE3327011A1 (de) Verfahren zum reinigen eines waessrigen dreiwertiges chrom enthaltenden elektrolyten
DE2008335A1 (de) Verfahren zum Entfernen von leitenden Schichten auf formbeständigen Elektroden
DE69514872T2 (de) Regenerierung von Elektrolysezelle-Diaphragmen
DE2232903C3 (de) Verfahren zur elektrolytischen Raffination von Kupfer unter Verwendung von Titanelektroden
DE2534272A1 (de) Verfahren zur elektrolytischen gewinnung von gallium und/oder alkalimetallen an einer auf eine traegerelektrode aufgebrachten quecksilberkathode
DE2940741C2 (fr)
EP1913181B1 (fr) Procede d'electropolissage
DE2060066A1 (de) Verfahren und Vorrichtung zur Herstellung von Magnesiumhydroxid und Chlor durch Elektrolyse waessriger Magnesiumchloridloesungen
DE19521596C1 (de) Verfahren und Vorrichtung zur elektolytischen Abscheidung von Zink und Kupfer aus saurer Lösung
DE2213528A1 (de) Verfahren zur Beseitigung verbrauchter Überzüge von metallischen Elektroden
DE2945566C3 (de) Elektrolytische Herstellung von Alkalichloraten
DE2011196C3 (de) Verfahren zur Entfernung bzw. Verringerung von Verunreinigungen in wäßrigen Alkalimetallhydroxidlösungen
DE60121337T2 (de) Verfahren zur verbesserung einer elektrode
DE10340197B3 (de) Verfahren zum elektrochemischen Abscheiden von Metallen aus einem Elektrolyt
DE1592022B1 (de) Verfahren zur entfernung von metallionen aus alkali hydroxydloesungen

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): CH DE FR GB IT LI

17P Request for examination filed

Effective date: 19970130

17Q First examination report despatched

Effective date: 19970819

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE FR GB IT LI

REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: SCHMAUDER & PARTNER AG PATENTANWALTSBUERO

Ref country code: CH

Ref legal event code: EP

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19981221

REF Corresponds to:

Ref document number: 59600938

Country of ref document: DE

Date of ref document: 19990121

ITF It: translation for a ep patent filed
ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20020412

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20020423

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20020517

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20020518

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030523

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030531

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030531

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF THE APPLICANT RENOUNCES

Effective date: 20030630

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20030523

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040130

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050523