EP0745701B1 - Verfahren zur Regenerierung von Kunststoffdiaphragmen - Google Patents
Verfahren zur Regenerierung von Kunststoffdiaphragmen Download PDFInfo
- 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
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.
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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)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Description
Claims (14)
- Verfahren zur Regenerierung von Kunststoffdiaphragmen, dadurch gekennzeichnet, daß eine Mineralsäurelösung, die bis zur Sättigungskonzentration Natriumchlorid enthält, mit einem Korrosionsinhibitor versetzt wird und die so erhaltene Mischung bei einer Temperatur von 0 bis 110°C 0,1 bis 84 Stunden durch das Kunststoffdiaphragma geleitet wird.
- Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Mineralsäurelösung in einer Konzentration von 0,3 bis 20 Gew.-% eingesetzt wird.
- Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß als Mineralsäure eine Säure, die zumindest teilweise aus Salzsäure besteht, verwendet wird.
- Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die Mineralsäurelösung bis zu 250 g/l Natriumchlorid enthält.
- Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß in der Mischung der Mineralsäurelösung mit dem Korrosionsinhibitor 0,005 bis 5 Gew.-% Korrosionsinhibitor vorgesehen ist, wobei die Gewichtsprozentangaben sich auf die Mischung der Mineralsäurelösung mit dem Korrosionsinhibitator als 100 Gew.-% beziehen.
- Verfahren nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß ein Korrosionsinhibitator verwendet wird, der mindestens ein Alkinol enthält.
- Verfahren nach Anspruch 6, dadurch gekennzeichnet, daß ein Korrosionsinhibitator verwendet wird, der ein Alkindiol enthält und mit 1 bis 25 Gew.-% eines Amins und/oder 0,1 bis 3 Gew.-% eines Tensids versetzt ist, wobei sich die Gewichtsprozentangaben auf den Korrosionsinhibitor als 100 Gew.-% beziehen.
- Verfahren nach Anspruch 7, dadurch gekennzeichnet, daß es sich bei den Aminen um Amine aus der Gruppe Hexamethylentetramin, Ethylhexylamin oder Diethylhexylamin handelt.
- Verfahren nach einem der Ansprüche 6 bis 8, dadurch gekennzeichnet, daß mindestens ein Tensid ein quartäres Ammoniumsalz enthält.
- Verfahren nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß die Mineralsäurelösung etwa 500 bis 5.000 ppm Kupfer- und/oder Eisenverbindungen enthält.
- Verfahren nach einem der Ansprüche 1 bis 10, dadurch gekennzeichnet, daß das Diaphragma zusätzlich mit Wasser und/oder einer Natriumchloridlösung gespült wird.
- Verfahren nach einem der Ansprüche 1 bis 11, dadurch gekennzeichnet, daß die Alkinole auch Alkinmonoole in einer Konzentration größer als 30 Gew.-% enthalten, wobei sich die Gewichtsprozentangabe auf die gesamten verwendeten Alkinole als 100 Gew.-% bezieht.
- Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Mischung durch eine Elektrolysezelle ohne vorhergehenden Ausbau von Diaphragma und Elektrode geleitet wird.
- Verfahren zur Regenerierung von Kunststoffdiaphragmen, dadurch gekennzeichnet, daß ein Verfahren nach einem der vorhergehenden Ansprüche mehrfach hintereinander oder mindestens zwei Verfahren nach einem der vorhergehenden Ansprüche hintereinander angewendet werden.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19519921 | 1995-05-31 | ||
DE19519921A DE19519921A1 (de) | 1995-05-31 | 1995-05-31 | Verfahren zur Regenerierung von Kunststoffdiaphragmen |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0745701A1 EP0745701A1 (de) | 1996-12-04 |
EP0745701B1 true EP0745701B1 (de) | 1998-12-09 |
Family
ID=7763296
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96108246A Expired - Lifetime EP0745701B1 (de) | 1995-05-31 | 1996-05-23 | Verfahren zur Regenerierung von Kunststoffdiaphragmen |
Country Status (6)
Country | Link |
---|---|
US (1) | US5755951A (de) |
EP (1) | EP0745701B1 (de) |
CN (1) | CN1077609C (de) |
DE (2) | DE19519921A1 (de) |
NO (1) | NO962216L (de) |
PL (1) | PL314547A1 (de) |
Families Citing this family (3)
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)
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 |
-
1995
- 1995-05-31 DE DE19519921A patent/DE19519921A1/de not_active Withdrawn
-
1996
- 1996-05-13 CN CN96110009A patent/CN1077609C/zh not_active Expired - Fee Related
- 1996-05-23 EP EP96108246A patent/EP0745701B1/de not_active Expired - Lifetime
- 1996-05-23 DE DE59600938T patent/DE59600938D1/de not_active Expired - Lifetime
- 1996-05-30 NO NO962216A patent/NO962216L/no not_active Application Discontinuation
- 1996-05-30 PL PL96314547A patent/PL314547A1/xx unknown
-
1997
- 1997-06-16 US US08/876,250 patent/US5755951A/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
NO962216L (no) | 1996-12-02 |
CN1147566A (zh) | 1997-04-16 |
DE19519921A1 (de) | 1996-12-05 |
DE59600938D1 (de) | 1999-01-21 |
CN1077609C (zh) | 2002-01-09 |
US5755951A (en) | 1998-05-26 |
NO962216D0 (no) | 1996-05-30 |
EP0745701A1 (de) | 1996-12-04 |
PL314547A1 (en) | 1996-12-09 |
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