WO1996015984A1 - Procede d'elimination d'impuretes metalliques par voie electrochimique - Google Patents
Procede d'elimination d'impuretes metalliques par voie electrochimique Download PDFInfo
- Publication number
- WO1996015984A1 WO1996015984A1 PCT/FR1995/001530 FR9501530W WO9615984A1 WO 1996015984 A1 WO1996015984 A1 WO 1996015984A1 FR 9501530 W FR9501530 W FR 9501530W WO 9615984 A1 WO9615984 A1 WO 9615984A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fibers
- cathode
- mixture
- blowing agent
- binder
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
- C25C7/02—Electrodes; Connections thereof
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D1/00—Oxides or hydroxides of sodium, potassium or alkali metals in general
- C01D1/04—Hydroxides
- C01D1/28—Purification; Separation
- C01D1/40—Purification; Separation by electrolysis
Definitions
- the present invention relates to a process for the purification of solutions whose pH is greater than 14 by electrochemical means, with the aim of reducing the metallic impurities in the trace state.
- the method according to the invention is suitable for the purification of alkali metal hydroxide solutions whose pH is greater than 14.
- the present invention further relates to a particular cathode capable of being used in the method according to the invention.
- electrolysis in diaphragm cells.
- mercury cells This process consists first of all in producing an amalgam of sodium and mercury from a saturated solution of sodium chloride, then in a second step in reacting said amalgam with water to give hydroxide of sodium.
- electrolysis in a membrane cell in which the anode and cathode compartments do not communicate.
- the present invention therefore relates to a process for purifying a solution whose pH is greater than 14, not having the aforementioned drawbacks.
- the method according to the invention consists in treating solutions whose pH is greater than 14, in an electrolysis cell, the cathode of which comprises a fibrous sheet based on a mixture of fibers of which at least part is conductive. electricity and a binder chosen from fluoropolymers, said etan fibrous sheet deposited on a porous support conducting electricity.
- solutions which can be treated according to the process of the invention are more particularly solutions of alkali metal hydroxide having a concentration of 40 to 800 g of alkali metal hydroxide per liter of solution.
- the method according to the invention makes it possible to obtain solutions having contents of metallic impurities of less than 1 mg / kg, or even as low as 0.01 mg / kg.
- One of the advantages of the process according to the invention is that the size of the tanks is up to 4 to 5 times smaller than that entailed by the abovementioned purification processes.
- the regeneration of the cathodes used is very simple and effective.
- the method according to the invention is implemented in an electrolysis cell whose cathode comprises a fibrous sheet consolidated by a fluoropolymer deposited on an electrically conductive support.
- the fibrous layer of the cathode also called microporous electroconductive material, conducts electricity. It more particularly has an electrical resistivity of between 0.5 and 15 Cl cm.
- the fibrous sheet is obtained from a mixture of fibers of which at least a fraction of the fibers is electrically conductive, possibly in association with non-conductive fibers.
- the electrically conductive fibers can be intrinsically conductive fibers or else treated so as to make them such.
- intrinsically conductive fibers are used, such as in particular carbon or graphite fibers.
- these fibers are in the form of filaments whose diameter is generally less than 1 mm and more particularly between 10 " 3 and 0.1 mm and whose length is greater than 0.5 mm and more especially between 1 and 20 mm.
- the conductive fibers preferably have a distribution of monodispersed length, that is to say a distribution such that the length of at least 80% and advantageously at least 90%, of the fibers , corresponds to the average length to within ⁇ 10%.
- non-conductive fibers possibly used, two categories can be recognized, organic fibers and mineral fibers.
- a first class of organic fibers is constituted by fibers of polypropylene, polyethylene, or among fibers of fluorinated polymers.
- Fluorinated polymers means homopolymers or copolymers derived at least in part from olefinic monomers substituted by fluorine atoms, or substituted by a combination of fluorine atoms and at least one of chlorine atoms, bromine or iodine, per monomer.
- homopolymers or fluorinated copolymers can be constituted by polymers and copolymers derived from tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, bromotrifluoroethylene.
- Such polymers can also comprise up to 75 mol% of units derived from other ethylenically unsaturated monomers containing at least as many fluorine atoms as carbon atoms, such as for example vinylidene (di) fluoride, esters vinyl and perfluoroalkyl, such as perfluoroalkoxyethylene.
- organic fibers made of polytetrafluoroethylene hereinafter called PTFE fibers are used.
- Organic fibers and more particularly PTFE fibers, generally have a diameter of 10 to 500 ⁇ m and a length such that the ratio of length to diameter is between 5 and 500.
- organic fibers are used. whose average dimensions are between 5 and 200 ⁇ m for the diameter and between 1 and 10 mm for the length.
- a second category of organic fibers consists of compounds based on cellulose fibers.
- such compounds are used with a cationic polymer, such as cationic starch.
- a cationic polymer such as cationic starch.
- Such compounds can thus be treated beforehand with this cationic polymer, or alternatively this polymer can be added to the fiber mixture independently of the compounds based on cellulose fibers.
- Fibers which have been given a positive ionic charge can be used, in particular by treatment of these fibers with a cationic polymer or starch. It is also possible to use fibers with a positive surface charge, sold by the company BECO, under the name Becofloc®.
- the fibers of the first category can be used in combination with the fibers of the second category.
- PTFE fibers can in particular be used in combination with the above-mentioned cellulose-based compounds.
- the mineral fibers are chosen from ceramic fibers such as zirconium dioxide fibers, silicon carbide, boron nitride, or even titanate fibers, titanium suboxide fibers of general chemical formula Ti n ⁇ 2n-1 with n, whole number, between 4 and 10 (of the Ebonex® type, manufactured and marketed by the company ATRAVERDA).
- the mixture of fibers also comprises a fluoropolymer consolidating all of the fibers. The definition given above for this type of polymer remains valid in this case and will therefore not be repeated here.
- This fluoropolymer, or binder is more particularly in the form of an aqueous dispersion containing 30 to 80% by weight of dry polymer, the particle size of which is between 0.1 and 5 ⁇ m and preferably between 0.1 and 1 ⁇ m.
- the fluoropolymer is polytetrafluoroethylene.
- mixture from which the fibrous web is obtained may comprise other additives such as in particular blowing or thickening agents, surfactants.
- any compound is suitable insofar as it can be eliminated by leaching or by thermal decomposition for example.
- derivatives based on silica are particularly interesting because they practically do not dissolve the microporous electroconductive material and form networks with the fiber-binding polymer, when the latter is used in the form of a latex
- sica derivatives is meant according to the invention precipitated silicas and combustion or pyrogenic silicas. They more particularly have a BET specific surface area of between 100 nrVg and 300 ⁇ g and or a particle size distribution evaluated with the COULTER® counter between 1 and 50 ⁇ m and, preferably, between 1 and 15 ⁇ m.
- nonionic compounds such as ethoxylated alcohols or fluorocarbon compounds with functionalized groups, generally having carbon chains comprising 6 to 20 carbon atoms.
- ethoxylated alcohols chosen from ethoxylated alkylphenols, such as in particular octoxynols, are used.
- thickening agents compounds capable of increasing the viscosity of the fiber mixture and which have water retentive properties.
- Natural or synthetic polysaccharides are generally used. Mention may in particular be made of the biopolymers obtained by fermentation of a carbohydrate under the action of microorganisms, such as xanthan gum or any other polysaccharide having similar properties.
- the electroconductive material is deposited on a porous support.
- Cloths or grids whose void, the perforations or the porosity can be between 20 ⁇ m and 5 mm are particularly suitable.
- These porous supports may have one or more flat or cylindrical surfaces, commonly called “thimble", having an open surface.
- the cathode used in the method according to the invention that is to say corresponding to the porous support and fibrous sheet assembly, has a large specific surface, necessary for obtaining good results (the cross section of the electrode is of the order of 20 to 50 m 2 / m * of useful electrode volume), while being relatively compact. This has a definite advantage in the case of industrial exploitation.
- a particular cathode is used, which also constitutes an object of the present invention.
- This cathode comprises a fibrous sheet obtained from a mixture of carbon fibers, compounds based on cellulose fibers, a cationic polymer, such as cationic starch.
- the cathode according to the invention may likewise comprise a fibrous sheet obtained from a mixture of carbon fibers, of compounds based on cellulose fibers treated beforehand with a cationic polymer, such as cationic starch.
- the fiber mixture further comprises a blowing agent such as silica, as well as a surfactant.
- the fibrous sheet deposited on the porous support conducting electricity is associated with a microporous diaphragm
- the diaphragm is deposited on the fibrous sheet in particular according to a preparation process as described below.
- Such diaphragms generally consist of a fibrous sheet comprising a mixture of organic and mineral fibers with a fluoropolymer binding these fibers.
- organic fibers mention may be made of polyethylene, polypropylene or fluorinated polymer fibers, as well as cellulose-based fibers.
- mineral fibers use may in particular be made of carbon, graphite, ceramic, titanate and titanium suboxide fibers.
- the associated diaphragm comprises a mixture of organic fibers and mineral fibers which are preferably chosen from carbon, graphite and titanate fibers.
- the diaphragm is not deposited on the fibrous sheet but is arranged separately so as to separate the anode and cathode compartments.
- the cathode comprising the fibrous sheet deposited on a support conducting electricity, is associated with a membrane.
- membranes suitable for the process according to the invention mention may be made of perfluorosutfonic membranes, of the National type (sold by the company DU PONT), or even perfluorinated membranes comprising carboxylic functional groups (series 890 or Fx- 50, sold by the company ASAHI GLASS). It is also possible to use bilayer membranes, comprising on one side sulfonic groups and on the other carboxylic groups.
- the cathode according to the invention can be obtained by wet method, by depositing under programmed vacuum a suspension comprising the constituent elements of the fibrous web, through a porous support. More particularly, the process for preparing the cathode consists in carrying out the following steps:
- an aqueous suspension comprising a mixture of fibers of which at least a fraction consists of electrically conductive fibers, a binder chosen from fluorinated polymers, a blowing agent, optionally additives;
- said suspension is deposited by filtration under programmed vacuum on a porous support;
- the resulting assembly is sintered at a temperature greater than or equal to the melting or softening temperature of the binder
- blowing agent is eliminated by a treatment carried out before or during the use of the cathode.
- the first step of the process consists in preparing a suspension comprising the constituent elements of the fibrous web.
- the suspension comprises a mixture of 20 to 80 parts by dry weight of conductive fibers, preferably from 20 to 40, and from 20 to 100 parts by dry weight of organic non-conductive fibers.
- cationic polymer such as cationic starch.
- the suspension can also comprise 10 to 100 parts by dry weight of mineral non-conductive fibers. More particularly, the suspension may comprise 20 to 60 parts by dry weight of non-conductive mineral fibers.
- the non-conductive mineral fibers are more particularly chosen from titanate fibers.
- the content of fluoropolymer binding the fibers is generally between 10 to 60 parts by dry weight.
- the suspension used in the process according to the invention usually comprises from 30 to 200 parts by dry weight of at least one blowing agent.
- the content of blowing agent is from 30 to 100 parts by dry weight.
- the content of thickening agent generally varies between 0 and 30 parts by dry weight. More particularly it is from 0 to 10 parts by dry weight.
- the suspension most often comprises at most 10 parts by dry weight of at least one surfactant, and more particularly a content of between 0.5 and 5 parts by dry weight.
- the fibrous sheet is formed by filtration under programmed vacuum of said suspension through a porous support
- This porous support may or may not conduct electricity. If the second case is implemented, then before the sintering step [d], the web is separated from the non-porous support. conductive and it is applied on a porous conductive support before sintering the assembly.
- the suspension obtained in step [a] is filtered under vacuum directly through the porous conductive support.
- the sheet is deposited on the porous support by programmed vacuum filtration.
- the tablecloth Once the tablecloth has been deposited, it is wrung out by maintaining the vacuum for a few moments and then optionally air-dried at a temperature between room temperature and 150 ⁇ C.
- the sheet is then sintered by heating to a temperature greater than or equal to the melting point of the fluoropolymer. During this sintering step, part of the constituents of the mixture from which the fibrous web is formed is generally thermally degraded.
- a step of removing the blowing agent is then carried out, in particular by means of an aqueous solution of alkali metal hydroxide.
- the elimination of the pore-forming agent can take place not only before the use of the microporous electroconductive material, but also "in situ", that is to say during the first moments of the use of the cathode. However, given the objective for which the latter is used, it may be preferable to avoid polluting the solution to be purified with the blowing agent dissolved during this step.
- the cathode used in the process according to the invention comprises an associated diaphragm
- the following steps are carried out: [a] an aqueous suspension comprising a mixture of fibers is prepared at least a fraction of which consists of electrically conductive fibers, a binder chosen from fluorinated polymers, a blowing agent, if necessary, additives;
- an aqueous dispersion comprising at least a mixture of organic and inorganic fibers, a binder, a blowing agent, optionally additives, is filtered on the resulting sheet.
- blowing agent is eliminated by a treatment carried out before the use of the cathode or during the use of the latter. Everything that has been said before regarding steps [a] to [e] remains valid and will not be repeated in this section.
- the dispersion prepared in step [fj therefore comprises a mixture of organic and mineral fibers.
- titanate fibers As mineral fibers, titanate fibers, carbon or graphite fibers, or a mixture thereof, are used. In the case where carbon or graphite fibers are used, their content is more particularly at least 2% by weight of the diaphragm. Preferably, the carbon fiber or graphite content does not represent more than 10% by weight of the diaphragm.
- organic fibers polytetrafluoroethylene fibers are used according to a more particular embodiment.
- the dispersion comprises a mixture of mineral and organic fibers whose content is between 30 and 80% by weight.
- the proportion of mineral fibers represents 1 to 80% by weight of the fiber mixture.
- the dispersion of step [f] further comprises a binder, the amount of which can vary between 3 and 35% by weight.
- the dispersion comprises a pore-forming agent, the amount of which is more particularly between 5 and 40% by weight.
- the dispersion can comprise additives such as surfactants, thickening agents, in a proportion generally varying between 0 and 5% by weight.
- step [d] is not compulsory insofar as the binder entering into the composition of each of the two layers is identical, or has a melting temperature of the same order of greatness.
- the sintering of the assembly of the two layers can advantageously be carried out after the deposition of the diaphragm.
- the solutions to be purified according to the process of the invention have a pH greater than 14.
- the process according to the invention is in particular suitable for the purification of solutions of alkali metal hydroxide.
- the solution to be treated is preferably obtained by electrolysis of a solution of a corresponding alkali metal halide. More particularly the invention is advantageous for the purification of solutions originating from the electrolysis carried out in a diaphragm cell. It should also be noted that it would not be departing from the scope of the present invention to purify a hydroxide solution of an alkali metal obtained from another method of preparation, insofar as the problem due to the presence of metals arises in similar terms.
- the solution to be treated is a sodium hydroxide solution.
- the metals likely to be present in the hydroxide solutions to be purified are chosen from iron, nickel, aluminum, chromium, vanadium, arsenic, selenium, lead, cadmium, manganese and copper. This list is of course not intended to be exhaustive.
- the metal content in the solution to be treated is at most a few hundred milligrams per kilogram of solution.
- the process according to the invention can be used to purify solutions whose content of alkali metal hydroxide is from 30 to 50% by weight, although contents outside are not excluded.
- the solution is preferably pretreated before the implementation of the purification process.
- the solution at the outlet of the electrolysis cell consisting of a mixture of alkali metal hydroxide and the starting halide, is concentrated and the precipitated halide salt is separated from the solution.
- This operation takes place according to methods known to those skilled in the art, for example by means of evaporators.
- desalting of the resulting solution is carried out in particular by reaction with ammonia.
- the solution to be treated is then introduced into an electrolysis cell comprising the cathode described above and an anode.
- the latter is usually made of nickel, nickel oxide or even stainless steel.
- the cathode can be either upstream or downstream of the anode.
- two implementation systems for the cell are particularly suitable for thimble cells or cassette cells.
- the cathode has a planar shape.
- a variant of the method according to the invention consists in using a commercial diaphragm, such as for example a diaphragm based on ceramic fibers. or Teflon.
- the diaphragm is mounted in the cell downstream or upstream of the anode.
- the flow rates of solutions to be purified vary over a wide range and depend on the quantity of solution to be purified, on the capacity of the electrolysis cell to treat it.
- the intensities applied are generally less than 2000 A / m *.
- the duration of a purification cycle is advantageously of the order of 500 to 1000 hours.
- the cathodes used in the process of the invention can be regenerated by any known means. Such regeneration may indeed be necessary because the polluting metals, during treatment, precipitate on the cathode, which can cause a variation in the permeability of the latter. Also, when the pressure necessary to obtain the same flow rate becomes too high, it is generally necessary to regenerate the cathode to make it reusable.
- This regeneration can be carried out electrochemically.
- a chemical method that is to say to use an acid of the hydrochloric, sulfuric or nitric acid type, or even a base such as sodium hydroxide.
- the solution thus purified has a content of metallic impurities of at most 1 mg / kg and can be as low as 0.01 mg / kg.
- the solutions obtained are made suitable for subsequent uses such as the preparation of sodium hypochlorite for which the coloring of iron was not desired.
- the solutions obtained can be used in food applications such as for the preparation of phosphates.
- the electrolysis cell has the following characteristics:
- Porous cathode support stainless steel composed of 2 mm wires and 2 mm meshes
- a suspension is prepared with stirring from the following compounds:
- PTFE fibers introduced in the form of a mixture of sodium chloride and PTFE fibers (50/50 by weight).
- PTFE fibers impregnated with sodium chloride are obtained beforehand by mixing, with stirring, one liter of water with approximately 100 g of a mixture containing approximately 50% of PTFE fibers and 50% of NaCl,
- the mixture thus obtained is deposited by filtration on a porous support of 10 cm 2 consisting of a braided and laminated iron grid whose opening is 2 mm and the diameter of the wires 2 mm.
- the filtration is carried out under vacuum programmed as follows: - 1000 Pa. Min- ⁇ for 10 min,
- a second suspension comprising:
- potassium titanate fibers (diameter between 0.2 and 0.5 ⁇ m, length from 10 to 20 ⁇ m),
- Filtration is carried out under programmed vacuum of 5000 Pa. Min * 1 to reach 80,000 Pa.
- the composite thus obtained is dried for 12 hours at 100 ° C. and consolidated by melting the fluoropolymer at 350 ° C. for 7 min.
- the weight deposited for this second layer is 1.5 kg / m *.
- the effluent treated is 50% sodium hydroxide desalted by a treatment with ammonia.
- the temperature of the soda purification treatment is 50 ° C.
- the solution to be treated is introduced into the anode compartment of the cell before percolating through the cathode obtained in point 1 /.
- the configuration is such that the anode is located upstream of the cathode.
- the electrode is regenerated.
- Regeneration is not necessarily complete and it corresponds to the dissolution of the metallic species deposited. It is carried out by percolation of 50% sodium hydroxide at 80 ⁇ C for approximately 24 hours with a flow varying between 150 l / hm 2 and 10001 / hm 2 at the end of regeneration.
- the cathode element thus regenerated is used.
- time (hours) represents the duration of the purification cycle
- the electrode can be regenerated and retain its purification capacity.
- the second suspension has the following composition:
- the effluent treated is 50% sodium hydroxide previously desalted as indicated in Example 1.
- the treatment is carried out at a temperature of 50 ° C.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Metallurgy (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Filtering Materials (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
Description
Claims
Priority Applications (9)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PL95320291A PL320291A1 (en) | 1994-11-21 | 1995-11-21 | Electrochemical method of removing metallic pollutants |
BR9509799A BR9509799A (pt) | 1994-11-21 | 1995-11-21 | Processo de purificação de uma solução cujo ph é superior a 14 para eliminar da mesma as inpurezas metálicas e catodo |
JP8516627A JPH10509685A (ja) | 1994-11-21 | 1995-11-21 | 電気化学的ルートによる金属不純物の除去プロセス |
AU41818/96A AU4181896A (en) | 1994-11-21 | 1995-11-21 | Method for electrochemically removing metal impurities |
US08/836,794 US5976349A (en) | 1994-11-21 | 1995-11-21 | Process for the removal of metal impurities by an electrochemical route |
EP95940339A EP0793620A1 (fr) | 1994-11-21 | 1995-11-21 | Procede d'elimination d'impuretes metalliques par voie electrochimique |
MX9703602A MX9703602A (es) | 1994-11-21 | 1995-11-21 | Proceso para la remocion de impurezas metalicas mediante ruta electroquimica. |
NO972250A NO972250L (no) | 1994-11-21 | 1997-05-16 | Fremgangsmåte for elektrokjemisk fjerning av metallforurensninger |
BG101496A BG101496A (en) | 1994-11-21 | 1997-05-19 | Method for electrochemically removing metal impurities |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR94/14122 | 1994-11-21 | ||
FR9414122A FR2727102B1 (fr) | 1994-11-21 | 1994-11-21 | Procede d'elimination d'impuretes metalliques par voie electrochimique |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996015984A1 true WO1996015984A1 (fr) | 1996-05-30 |
Family
ID=9469133
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR1995/001530 WO1996015984A1 (fr) | 1994-11-21 | 1995-11-21 | Procede d'elimination d'impuretes metalliques par voie electrochimique |
Country Status (12)
Country | Link |
---|---|
US (1) | US5976349A (fr) |
EP (1) | EP0793620A1 (fr) |
JP (1) | JPH10509685A (fr) |
AU (1) | AU4181896A (fr) |
BG (1) | BG101496A (fr) |
BR (1) | BR9509799A (fr) |
CA (1) | CA2205073A1 (fr) |
FR (1) | FR2727102B1 (fr) |
MX (1) | MX9703602A (fr) |
NO (1) | NO972250L (fr) |
PL (1) | PL320291A1 (fr) |
WO (1) | WO1996015984A1 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CZ305048B6 (cs) * | 2014-01-21 | 2015-04-08 | Vysoká škola chemicko- technologická v Praze | Rafinace hydroxidů metodou membránové elektrolýzy se železnou elektrodou |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2803309B1 (fr) * | 1999-12-30 | 2002-05-03 | Chloralp | Diaphragme exempt d'amiante, comprenant des particules minerales non fibreuses, association le comprenant, son obtention et son utilisation |
US6660828B2 (en) | 2001-05-14 | 2003-12-09 | Omnova Solutions Inc. | Fluorinated short carbon atom side chain and polar group containing polymer, and flow, or leveling, or wetting agents thereof |
AR090394A1 (es) * | 2011-10-27 | 2014-11-12 | Syngenta Participations Ag | Formulacion |
CN109264745A (zh) * | 2018-12-07 | 2019-01-25 | 青海盐湖工业股份有限公司 | 一种片状氢氧化钾生产方法 |
CN113564680B (zh) * | 2021-09-26 | 2021-12-07 | 江苏泛宇能源有限公司 | 铁铬电解液的纯化方法及由此获得的铁铬电解液 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1567928A1 (de) * | 1966-02-15 | 1970-10-01 | Dow Chemical Co | Verfahren zur Reinigung von waesserigen kaustischen Loesungen |
US3989615A (en) * | 1971-07-06 | 1976-11-02 | Nippon Soda Company Limited | Diaphragm process electrolytic cell |
EP0214066A1 (fr) * | 1985-08-02 | 1987-03-11 | Rhone-Poulenc Chimie | Matériau consolidé microporeux, procédé pour son obtention, et applications notamment à la réalisation d'éléments cathodiques |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5092974A (en) * | 1990-01-25 | 1992-03-03 | Shinko Pantec Co., Ltd. | Electrode and method for compressive and electro-osmotic dehydration |
-
1994
- 1994-11-21 FR FR9414122A patent/FR2727102B1/fr not_active Expired - Fee Related
-
1995
- 1995-11-21 CA CA002205073A patent/CA2205073A1/fr not_active Abandoned
- 1995-11-21 BR BR9509799A patent/BR9509799A/pt not_active Application Discontinuation
- 1995-11-21 AU AU41818/96A patent/AU4181896A/en not_active Abandoned
- 1995-11-21 JP JP8516627A patent/JPH10509685A/ja active Pending
- 1995-11-21 PL PL95320291A patent/PL320291A1/xx unknown
- 1995-11-21 WO PCT/FR1995/001530 patent/WO1996015984A1/fr not_active Application Discontinuation
- 1995-11-21 MX MX9703602A patent/MX9703602A/es unknown
- 1995-11-21 EP EP95940339A patent/EP0793620A1/fr not_active Withdrawn
- 1995-11-21 US US08/836,794 patent/US5976349A/en not_active Expired - Fee Related
-
1997
- 1997-05-16 NO NO972250A patent/NO972250L/no not_active Application Discontinuation
- 1997-05-19 BG BG101496A patent/BG101496A/xx unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1567928A1 (de) * | 1966-02-15 | 1970-10-01 | Dow Chemical Co | Verfahren zur Reinigung von waesserigen kaustischen Loesungen |
US3989615A (en) * | 1971-07-06 | 1976-11-02 | Nippon Soda Company Limited | Diaphragm process electrolytic cell |
EP0214066A1 (fr) * | 1985-08-02 | 1987-03-11 | Rhone-Poulenc Chimie | Matériau consolidé microporeux, procédé pour son obtention, et applications notamment à la réalisation d'éléments cathodiques |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CZ305048B6 (cs) * | 2014-01-21 | 2015-04-08 | Vysoká škola chemicko- technologická v Praze | Rafinace hydroxidů metodou membránové elektrolýzy se železnou elektrodou |
Also Published As
Publication number | Publication date |
---|---|
CA2205073A1 (fr) | 1996-05-30 |
PL320291A1 (en) | 1997-09-15 |
MX9703602A (es) | 1997-08-30 |
NO972250D0 (no) | 1997-05-16 |
JPH10509685A (ja) | 1998-09-22 |
US5976349A (en) | 1999-11-02 |
EP0793620A1 (fr) | 1997-09-10 |
NO972250L (no) | 1997-07-21 |
BG101496A (en) | 1998-01-30 |
FR2727102A1 (fr) | 1996-05-24 |
BR9509799A (pt) | 1997-09-30 |
AU4181896A (en) | 1996-06-17 |
FR2727102B1 (fr) | 1997-08-01 |
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