US3250691A - Electrolytic process of decomposing an alkali metal chloride - Google Patents

Electrolytic process of decomposing an alkali metal chloride Download PDF

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Publication number
US3250691A
US3250691A US198216A US19821662A US3250691A US 3250691 A US3250691 A US 3250691A US 198216 A US198216 A US 198216A US 19821662 A US19821662 A US 19821662A US 3250691 A US3250691 A US 3250691A
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anode
cell
alkali metal
platinum
electrolysis
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Expired - Lifetime
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US198216A
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English (en)
Inventor
Jr Thorowgood Taylor Broun
Howard H Hoekje
Martinsons Aleksandrs
Paul P Anthony
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PPG Industries Inc
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Pittsburgh Plate Glass Co
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Priority to US198216A priority Critical patent/US3250691A/en
Priority to NL290793D priority patent/NL290793A/xx
Priority to NL290793A priority patent/NL126636C/xx
Priority to FR933231A priority patent/FR1360905A/fr
Priority to GB20795/63A priority patent/GB997887A/en
Priority to DEP31887A priority patent/DE1226089B/de
Priority to CH664363A priority patent/CH419072A/fr
Priority to US345551A priority patent/US3287250A/en
Application granted granted Critical
Publication of US3250691A publication Critical patent/US3250691A/en
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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
    • C25B15/00—Operating or servicing cells
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C25B11/081—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the element being a noble metal

Definitions

  • This invention relates to the electrolysis of an alkali metal chloride solution in an electrolytic cell resulting in the production of chlorine and alkali metal products. More particularly, this invention relates to the electrolysis of an aqueous solution of alkali metal chloride in an electrolytic cell wherein the anode has a specially treated platinum surface. In addition, this invention relates to the treated anode and the environmentin which it is employed.
  • Increased power consumption in an electrolytic cell for the electrolytic decomposition of an alkali metal chloride results, in part, from the dissolution or erosion ofthe anode within the cell. As the size of the anode is thereby reduced, the distance between the anode and cathode is increased. This results in increased internal resistance within the cell requiring consequent voltage increase to maintain the applied current level.
  • This discovery may be effected by treating a platinum surface anode in an electrolytic cell as a cathode therein, which cell contains a treating electrolyte. passed across the anode and cathode of the cell, causing electrolytic decomposition of the electrolyte. After this treatment, the treated platinum surface anode is employed A current is v as an anode in an electrolytic cell containing product alkali metal chloride in aqueous solution in contact with said anode. Electrolysis of the solution is effected while the solution has a pH below about 5, preferably below 3.5, and typically above a pH of 1.
  • the process of this invention may be effected in any electrolytic cell capable of discharging chlorine at the anode and alkali metal product (e.g., sodium or potassium hydroxide and/ or carbonate) at the cathode.
  • alkali metal product e.g., sodium or potassium hydroxide and/ or carbonate
  • Typical cells in which the process and treated anode of this invention may be employed are disclosed in US. Patents 2,542,523, 2,858,263 and 2,409,912.
  • process of this invention is desirably used for the electrolysis of saturated aqueous sodium chloride brine solution, more dilute or more concentrated aqueous solutions of sodium chloride may also be employed, e.g., from 5 percent by weight of salt saturation to above percent by weight of salt saturation.
  • Other product electrolytes (alkali metal chloride) included within the terms of this invention are aqueous solutions of lithium chloride and potassium chloride.
  • the platinum surface anode of this invention comprises any electrode having a platinum surface.
  • the anode may be solid, unitary platinum, a platinum clad electrode, or a platinum coated electrode.
  • the platinum coated electrode is found the most favorable because of extended life when employed as an anode during the electrolysis of aqueous alkali metal chloride solutions.
  • a platinum coated anode typically requires only one cationic treatment to operate under conditions of continuous electrolysis for one year or more with low power consumption.
  • Unitary platinum and platinum clad electrodes generally require more periodic cationic treatment, for example, once every month during a continuously operated electrolytic process. I
  • the coated platinum anode includes vapor deposited, chemically deposited or electrolytically deposited platinum coating on a metal base.
  • the vapor deposition conventionally involves, for example, plasma jet spraying of platinum metal vapor on a metal base.
  • Chemical deposition can be effected by coating platinum salt on a ,metal base followed by firing of the coating.
  • Electrolytic deposition involves plating a metal electrode with platinum by the electrolytic reduction of a platinum salt.
  • the metal base may take the form of a plate, bar, screen -or cylinder.
  • the shape of the base is not critical to the invention except insofar as its specific employment within a particular type of electrolytic cell operated under certain controlled conditions. This feature of the base is within the province of the skilled worker in the application of the invention herein disclosed.
  • the base is made of a metal such as titanium and tantalum, which represent the preferred base materials in the operation of this invention.
  • a metal such as titanium and tantalum
  • Other metals may 5 be employed with significant efficiency, but typically their overall utility does not measure up to titanium and tantalum. Included within this class are platinum, tungsten, aluminum, vanadium, niobium (columbium) and paladium. With regard to the latter metals, it is de sirable thatthe platinum coating thereon be at least 100 micro inches thick. When titanium or tantalum is the base material, the platinum coating as a rule should be at least 3 micro inches thick. Because of operational bene fits, platinum coated titanium is found to be the mos-t desirable anode employable in the operation of the process of this invention.
  • the platinum surface anode is electrolytically treated under an electrolytically induced cationic environment prior to'its use in the decomposition of the aforementioned chloride solution.
  • the type of cations which effect this treatment can result from the electrolytic decomposition of any inorganic or organic electrolyte which is inert to the platinum surface, that is, does not decompose or erode it during the treatment, i.e., electrolysis.
  • the treating electrolyte may be, for example, an aqueous solution of alkali metal chloride (such as NaCl, KCl or LiCl) sodium dichromate, potassium chromate, calcium sulphate, potas sium permanganate, sodium acetate or N-trimethyl-benzyl ammonium chloride.
  • the cationic treatment of the platinum surfaced anode involves, in effect, reversing the direction of the current to the anode from that employed when it is an anode in the electrolytic decomposition of the product alkali metal chloride.
  • the language cation discharge at the platinum surface anode is meant to encompass the utilization of the platinum surface anode as a cathode in an electrolytic cell during electrolysis of an electrolyte.
  • the platinum surface anode is employed as a cathode in an electrolytic cell containing the aforementioned treating electrolytes so that positive ions (cations) are discharged at the platinum surface electrode (anode).
  • This cationic treated anode is inserted in the cell provided for the electrolysis of product acidic aqueous alkali metal chloride solution so that negative ions (anions) are discharged at its surface.
  • negative ions anions
  • The-cationic treatment of the platinum surface electrode may be effected prior to the utilization of the electrode in the electrolytic decomposition of the product alkali metal chloride or may be effected during the decomposition thereof. If the anode is treated prior to the electrolysis of product alkali metal chloride, then such is preferably done in an electrolytic cell other than that employed for producing chlorine and alkali metal products. After treatment, the electrode may be inserted in the brine cell as an anode for the manufacture of chlorine and alkali metal products.
  • initial electrolysis of the product alkali metal chloride may be effected with an untreated platinum surface anode in the cell.
  • the electrode treatment under these conditions may be effected when the cells power consumption shows an undesirable increase.
  • Polarity reversal in the cell containing the platinum surface anode as the cathode therein should be maintained for a period of at least /2 to 1 second.
  • current reversal is effected in the cell employed for the electrolytic decomposition of, for example, sodium chloride brine solution
  • reversal as a rule should not exceed a period of about seconds.
  • a substantially longer period of reversal tends tov damage the anode therein and also creates a hazardous and explosive environment resulting from excessive hydrogen discharge at the anode.
  • the reversal treatment period may be maintained up to 1 hour or more.
  • the anode After the current across the platinum surface anode has been reversed, the anode may be established as such in the cell for the electrolytic decomposition of the product alkali metal chloride. Surprisingly enough, a platinum surface anode to which current reversal has been effected may be stored for an apparently unlimited time before again used in the aforementioned electrolytic decomposition process. It is found that the treated anode acquires a memory. of the effect of current reversal which appears to last indefinitely. For example, when the current is reversed across a platinum coated anode and it is thereafter stored for a long time, for example, 6 months,
  • the treated anodes of this invention constitute a saleable item per se.
  • Acidification of the aqueous alkali metal chloride solution to the pH values described above, before or concurrent with the start of electrolysis in the cell, serves to maintain the reduced voltage obtained by treating the anode.
  • the solution should be maintained acidic throughout the electrolysis reaction. If the pH of the solution is allowed to rise above a pH of 5, electrolysis must be stopped or else platinum loss from the treated anode will be excessive.
  • Acidification may be accomplished by adding acid to the alkali metal chloride solution in the cell or by reconstituting the salt solution in the cell by replacing it wih acidified aqueous alkali metal chloride.
  • the desired pH is achieved by the continuous addition of acidic aqueous alkali metal chloride solution to the cell at the start of and during electrolysis. Any one or combination of the above methods for acidification may be effectively employed.
  • Usable acids contemplated for acidifying the aforementioned product electrolyte are the mineral acids, such as hydrochloric acid, sulfuric acid or hydrofluoric acid, or the known strong organic acids.
  • acidification is eifected with hydrochloric acid (dilute or concentrated) as described above.
  • the temperature of the product alkali metal chloride solution during electrolysis may range from above 20 C tothe boiling point of the solution.
  • the temperature of the product solution during electrolysis is above 50 C., and for the most effective results, maintained above C. to the boiling point of the solution.
  • aqueous sodium chloride brine solution is electrolyzed in a compartmental cell.
  • This type of cell has an anode-containing compartment (anolyte compartment) and a cathode-containing compartment (catholyte compartment) separated by a barrier.
  • These barriers are. either permionic or non-permionic.
  • a typical cell containing a permionic barrier (or membrane) is described in copending application, Serial No. 29,559, filed May 17, 1960, and now abandoned.
  • a typical non-permionic barrier is an asbestos diaphragm.
  • a cell used in such a diaphragm is described in US. Patent No. 2,409,912. Of course, this does not preclude the desirable benefits accruing when the process of this invention and the treated anodes herein disclosed are employed in well-known mercury cells.
  • cylindrical glass tanks 1 and 3 are openly connected through cylinder 2. Near the base of the side wall of tank 1 is tank opening 15, where aqueous alkali metal chloride solution is introduced. Provided at the bottom of tank 1 is platinum coated anode 4.
  • the rod is connected to anode collar 7, to which is attached lead 7 connected to a power source.
  • Immersed a 2-inch inside diameter and cylindrical glass tank 3 has a 1 /2inch inside diameter.
  • Cylinder -2 connecting tanks 1 and 3 has a 1-inch internal diameter and is 2 inches in length. Centered intermediate the length 227 (Anodes inspected for platinum).
  • the ode which may be made of conventional cathodic anode is made of titanium metal, onto which is elecilliii ifii i $552122? $3152 5! 6.525 3.1? if i i- 3 i 1 *'O t E il? r 1c 1n on e 1 anlum me a ase 1s microinc est ic turn is connected to lead 11 attached to the corresponding mersed in tank 1 is an electrical heater 13 for temperapower source. Immersed below the surface of catholyte ture control of the bath.
  • Anode 4 is connected through 17111s glaiss tulaie 14 serving to remove catholyte from th 15 platinum wire 5 to lead 7.
  • esire ode 8 which is a platinum wire having a 0.025 inch Central positioned 1n cylinder 2 is diaphragm 12 diameter.
  • Cathode 8 is connected to lead 11.
  • Both Whlch y be a 1161111101110 membrane Such as an leads 7 and 11 are connected to appropriate power diaphragm impregnated with a P y 0f maleic e sources.
  • a saturated aqueous so- Current reversal across the platinum coated anode 4 2 51 5 13 g gs i g gi i s g g f 15 may be readily efiected during electrolysis of product t C b h i electrolyte in the aforementioned cell by reversing the 25 emperature O y eater unent Passe leads to the electrode.
  • the lead 7 may be atthrough the anode at a currentldenslty of 9 atlperes tached to collar 10 and lead 11 attached to collar 9. per Square foot, and a Voltage of 1s provlded the Other methods for current reversal will be readily apq measured by a voltmeter attached to Parent to the artisan the terminals of the anode and the cathode within the I ddi i h for ti d ll may l h cell. After 40 days of electrolysis, the voltage increases employed for treating the platinum surface an d Th to 3.8 volts.
  • the leads connecting the anode the electrodes can be reand the cathode are reversed and current is then reversed.
  • cathode 8 can be immersed in established at the same level.
  • anode 4 tank 1 and Pt surface anode 4 can be immersed in tank becomes the cathode and cathode 8 becomes the anode.
  • the electrolytes employed under these conditions Hydrogen is discharged at platinized anode4 and chlorine y be y 9 0f the tl'eatlqg electmlytes Escflbed is discharged at platinum wire 8. This reversal lasts above and within the contemplation of this invention.
  • h l d are thls arrangemen't: the treamfg electrolyte 1S fed to tank re-adjusted so that chlorine is formed around the plat- 1 through Opemng Thls e arrangement may be inized anode 4 and hydrogen is discharged at the platinum pemganenflg ig for treatng one 3;
  • the 40 wire cathode 8 i.e., anode 4 is re-employed as an anode ano es an e P a mum Sm ace ano es can 6 and cathode 8 is re-employed as a cathode.
  • the cell Before curmoved therefrom after treatment for employment in rent to the cell is so re-established, the pH of the sodium the production of alkali products and chlorine in an chloride brmesolution 1n the cell is ad usted to 3 by alkali chlorine cell.
  • reversing the polarity of t 6 ad mono to e ano e tan mm a e the bus bars by a double pole, double throw switch will ther-eefier to the Cell h a PH no greater than serve to reverse the polarity within the caustic chlorine
  • Tent 13 then re'estabhshed at 100 amperes Per Square cell.
  • Such a technique can be operated by inserting a foot and the voltage p acmss the cell 15 found to be voltmeter into the circuit which on showing, for example, Voltsa 1 percent voltage increase, automatically signals and EXAMPLE H initiates polarity reversal within the cell.
  • Anode had 12.8 micro inches 3 ghickness of platinum.
  • Anode had 3.3 micro inches of platinumremoved this anode as unfit for further electrolysis ⁇ necause of excessive platinum oss.
  • the platinized titanium anode in tank 3 After electrolyzing said solution at a temperature of 25 C. using a voltage of 5.0 and a current density of 100 amperes per square foot for 5 minutes, the platinized titanium anode in tank 3 is removed. The pH of the aqueous solution, on addition to the cell, is in excess of l4.
  • the platinized anode removed from tank 3 is laid on a laboratory supply shelf for 3 months and then reemployed in the cell described in Example I as the anode portion thereof.
  • the operating conditions of electrolysis are the same as those employed in Example I using an acidified saturated sodium chloride brine solution having a pH of 3.
  • the electrolysis is started only after the pH of the anolyte has this value.
  • the cathode in tank 3 is the platinum wire described in Example I.
  • the voltage drop in the cell as measured across the electrodes is 3.6. After days, the voltage is not found to increase by more than 1 percent of the voltage drop value and many times the voltage drop is found to fall below 3.6. After a continuous run of 50 days, the platinized titanium anode is removed from the cell and examined for platinum loss. It is found that platinum loss is not detectable.
  • the voltage of the cell immediately increases more than 5 percent of the initial voltage of thecell within hours from the start of electrolysis.
  • the current density at the anode during current reversal treatment thereof is above 20 percent of the current density prior to reversal, usually not more than 150 percent of the current density prior to reversal. If reversal is effected in a cell separate from the product chlorine-alkali cell, thenthe current density employed for current reversal treatment is typically above 20 percent of the current density to be employed in the chlorinealkali cell and usually not above 150 percent of this current density value.
  • a further and more specific embodiment of this invention involves employing a platinum surface anode having a low chlorine over-voltage. It has been noted that the aforementioned beneficial and long-lasting effects resulting from electrolysis of acidified aqueous alkali metal chloride (e.g. NaCl) brine solution is obtained when the platinum surface anode has a low chlorine over-voltage, typically in the range of from about 0.03 to 0.15 volt.
  • One way of obtaining a platinum surface anode having a low chlorine over-voltage is to effect the aforementioned cationic treatment by discharging cations at the patinum surface anode as discussed above and disclosed in the above examples.
  • An anode treated in this fashion maintains the aforementioned low chlorine over-voltage when used in the electrolysis of acidic brine soluton having a pH below about 5. However, if electrolysis at any time is effected wherein the anolyte has a pH exceeding 5, the anode reverts to a high chlorine over-voltage, typically about 0.5 to 0.6 volt. In addition, deterioration of the anode, as previously discussed, is found to occur.
  • an aqueous alkali metal chloride solution in an alkali-chlorine cell having a platinum surface anode the improvement which comprises contacting said anode with an electrolyte selected from the group consisting of aqueous solutions of alkali metal salts and alkaline earth metal salts, electrolyzing said electrolyte while using said anode as a cathode, subsequently employing said platinum surface anode so contacted in an alkalichlorine cell as an anode therein, providing an aqueous alkali metal chloride solution in said alkali-chlorine cell, electrolyzing said alkali metal chloride solution by passing current through said alkali-chlorine cell While maintaining the pH of said alkali metal chloride solution at below 5.
  • an electrolyte selected from the group consisting of aqueous solutions of alkali metal salts and alkaline earth metal salts
  • the improvement which comprises feeding aqueous sodium chloride to the cell so as to contact said anode, passing a current across the cell thereby electrolytically decomposing sodium chloride, reversing the polarity of the current to the cell whereby said anode acts as a cathode therein, again reversing the polarity of the current to the cell whereby said anode acts as an anode in the cell While concurrently therewith providing that the pH of the aqueous sodium chloride solution is below 5.

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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)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
US198216A 1962-05-28 1962-05-28 Electrolytic process of decomposing an alkali metal chloride Expired - Lifetime US3250691A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US198216A US3250691A (en) 1962-05-28 1962-05-28 Electrolytic process of decomposing an alkali metal chloride
NL290793D NL290793A (de) 1962-05-28 1963-03-28
NL290793A NL126636C (de) 1962-05-28 1963-03-28
FR933231A FR1360905A (fr) 1962-05-28 1963-04-30 Procédé d'électrolyse d'une solution de chlorure alcalin et appareillage utilisé
GB20795/63A GB997887A (en) 1962-05-28 1963-05-24 Electrolysis of alkali metal chloride solution
DEP31887A DE1226089B (de) 1962-05-28 1963-05-25 Verfahren zur Elektrolyse von Alkalimetall-chloridloesungen
CH664363A CH419072A (fr) 1962-05-28 1963-05-28 Procédé d'électrolyse d'une solution de chlorure de métal alcalin
US345551A US3287250A (en) 1962-05-28 1964-01-20 Alkali-chlorine cell containing improved anode

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US198216A US3250691A (en) 1962-05-28 1962-05-28 Electrolytic process of decomposing an alkali metal chloride

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CH (1) CH419072A (de)
DE (1) DE1226089B (de)
FR (1) FR1360905A (de)
GB (1) GB997887A (de)
NL (2) NL290793A (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3485730A (en) * 1967-06-02 1969-12-23 Hooker Chemical Corp On-off operation of chlor-alkali diaphragm cells
US4110181A (en) * 1975-10-08 1978-08-29 Solvay & Cie Method of handling aqueous solutions of alkali metal hydroxides that are concentrated in respect of alkali metal halides
US4488947A (en) * 1983-06-08 1984-12-18 Olin Corporation Process of operation of catholyteless membrane electrolytic cell
US6267854B1 (en) 1999-10-21 2001-07-31 Orville Lee Maddan Apparatus and method for producing magnesium from seawater
US6372017B1 (en) 2000-02-07 2002-04-16 Orville Lee Maddan Method for producing magnesium
WO2003082749A1 (en) * 2002-03-28 2003-10-09 Hanwha Chemical Corporation Electrolyte composition for electrolysis of brine, method for electrolysis of brine, and sodium hydroxide prepared therefrom
US20040060815A1 (en) * 1999-08-06 2004-04-01 Sterilox Medical (Europe) Limited Electrochemical treatment of an aqueous solution
US20070051640A1 (en) * 2000-08-07 2007-03-08 Sterilox Technologies, Inc. Electrochemical treatment of an aqueous solution
US20070070882A1 (en) * 2005-07-19 2007-03-29 Sony Corporation OFDM demodulating apparatus and method
US7824538B2 (en) * 2001-10-12 2010-11-02 Flexsys B.V. Process for improving the purity of quaternary ammonium hydroxides by electrolysis in a two-compartment cell

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4185905A (en) * 1978-04-03 1980-01-29 Polaroid Corporation Dual purpose flash/strobe socket assembly for a photographic camera
IT1263899B (it) * 1993-02-12 1996-09-05 Permelec Spa Nora Migliorato processo di elettrolisi cloro-soda a diaframma e relativa cella

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2823177A (en) * 1954-01-13 1958-02-11 Hooker Electrochemical Co Method and apparatus for lowering the chlorate content of alkali metal hydroxides
US2827426A (en) * 1954-02-12 1958-03-18 Rohm & Haas Cationic permselective membranes and their use in electrolysis
US2872405A (en) * 1955-12-14 1959-02-03 Pennsalt Chemicals Corp Lead dioxide electrode
US2929769A (en) * 1955-07-07 1960-03-22 Isaac L Newell Electroplating anode
US2954333A (en) * 1957-07-11 1960-09-27 Columbia Southern Chem Corp Method of electrolyzing brine
US2987453A (en) * 1959-04-14 1961-06-06 Harshaw Chem Corp Method of electrodepositing chromium
US3096261A (en) * 1959-05-25 1963-07-02 Hooker Chemical Corp Salt bath for electrolytic cleaning of metals

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2823177A (en) * 1954-01-13 1958-02-11 Hooker Electrochemical Co Method and apparatus for lowering the chlorate content of alkali metal hydroxides
US2827426A (en) * 1954-02-12 1958-03-18 Rohm & Haas Cationic permselective membranes and their use in electrolysis
US2929769A (en) * 1955-07-07 1960-03-22 Isaac L Newell Electroplating anode
US2872405A (en) * 1955-12-14 1959-02-03 Pennsalt Chemicals Corp Lead dioxide electrode
US2954333A (en) * 1957-07-11 1960-09-27 Columbia Southern Chem Corp Method of electrolyzing brine
US2987453A (en) * 1959-04-14 1961-06-06 Harshaw Chem Corp Method of electrodepositing chromium
US3096261A (en) * 1959-05-25 1963-07-02 Hooker Chemical Corp Salt bath for electrolytic cleaning of metals

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3485730A (en) * 1967-06-02 1969-12-23 Hooker Chemical Corp On-off operation of chlor-alkali diaphragm cells
US4110181A (en) * 1975-10-08 1978-08-29 Solvay & Cie Method of handling aqueous solutions of alkali metal hydroxides that are concentrated in respect of alkali metal halides
US4488947A (en) * 1983-06-08 1984-12-18 Olin Corporation Process of operation of catholyteless membrane electrolytic cell
US20040060815A1 (en) * 1999-08-06 2004-04-01 Sterilox Medical (Europe) Limited Electrochemical treatment of an aqueous solution
US7303660B2 (en) * 1999-08-06 2007-12-04 Puricore International Ltd. Electrochemical treatment of an aqueous solution
US6267854B1 (en) 1999-10-21 2001-07-31 Orville Lee Maddan Apparatus and method for producing magnesium from seawater
US6372017B1 (en) 2000-02-07 2002-04-16 Orville Lee Maddan Method for producing magnesium
US20070051640A1 (en) * 2000-08-07 2007-03-08 Sterilox Technologies, Inc. Electrochemical treatment of an aqueous solution
US7824538B2 (en) * 2001-10-12 2010-11-02 Flexsys B.V. Process for improving the purity of quaternary ammonium hydroxides by electrolysis in a two-compartment cell
WO2003082749A1 (en) * 2002-03-28 2003-10-09 Hanwha Chemical Corporation Electrolyte composition for electrolysis of brine, method for electrolysis of brine, and sodium hydroxide prepared therefrom
US20040238373A1 (en) * 2002-03-28 2004-12-02 Dae-Sik Kim Electrolyte composition for electrolysis of brine, method for electrolysis of brine, and sodium hydroxide prepared therefrom
CN1309871C (zh) * 2002-03-28 2007-04-11 韩化石油化学株式会社 盐水电解用电解液组合物、盐水电解方法及其制备的氢氧化钠
US20070070882A1 (en) * 2005-07-19 2007-03-29 Sony Corporation OFDM demodulating apparatus and method

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Publication number Publication date
DE1226089B (de) 1966-10-06
FR1360905A (fr) 1964-05-15
CH419072A (fr) 1966-08-31
NL290793A (de) 1965-06-25
NL126636C (de) 1969-06-16
GB997887A (en) 1965-07-14

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