EP0571273A1 - Procédé de fabrication de chlorate de métal alcalin et dispositif pour sa mise en oeuvre - Google Patents

Procédé de fabrication de chlorate de métal alcalin et dispositif pour sa mise en oeuvre Download PDF

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Publication number
EP0571273A1
EP0571273A1 EP93401275A EP93401275A EP0571273A1 EP 0571273 A1 EP0571273 A1 EP 0571273A1 EP 93401275 A EP93401275 A EP 93401275A EP 93401275 A EP93401275 A EP 93401275A EP 0571273 A1 EP0571273 A1 EP 0571273A1
Authority
EP
European Patent Office
Prior art keywords
alkali metal
chlorine
cell
solution
recovering
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.)
Ceased
Application number
EP93401275A
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German (de)
English (en)
French (fr)
Inventor
François Delmas
Dominique Ravier
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.)
Arkema France SA
Original Assignee
Elf Atochem SA
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 Elf Atochem SA filed Critical Elf Atochem SA
Publication of EP0571273A1 publication Critical patent/EP0571273A1/fr
Ceased legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/24—Halogens or compounds thereof
    • C25B1/26—Chlorine; Compounds thereof
    • C25B1/265—Chlorates
    • 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
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/34—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
    • C25B1/46—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis in diaphragm 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
    • C25B15/00—Operating or servicing cells
    • C25B15/02—Process control or regulation
    • 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
    • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
    • C25B15/085—Removing impurities

Definitions

  • the present invention relates to a process for the manufacture of alkali metal chlorate by electrolysis in a membrane cell without the addition of chromium.
  • Membrane cells generally consist of two compartments, one anodic, the other cathodic, separated by a membrane which allows the selective transfer of ions from one compartment to another, under the action of an electric field. .
  • the anolyte consists of a chloride salt brine of said alkali metal, to which may be added, if necessary, a determined quantity of chlorate of the same alkali metal, the catholyte being for its part consists of an alkali metal hydroxide solution.
  • membrane cells require the use of electrolytes which are particularly free of impurities.
  • the brine of alkali metal chloride salt which feeds the anode compartment of the cell contains small amounts of metal salts, particularly salts of alkaline earth metals, metals such as aluminum, copper, manganese or zinc, or impurities such as silica, sulfate salts, bromine or iodine that may damage or clog the membrane during electrolysis.
  • metal salts particularly salts of alkaline earth metals, metals such as aluminum, copper, manganese or zinc, or impurities such as silica, sulfate salts, bromine or iodine that may damage or clog the membrane during electrolysis.
  • the present invention therefore relates to a process for the preparation of alkali metal chlorate by electrolysis in a membrane cell, of an anolyte comprising a solution of alkali metal chloride and of a catholyte comprising a solution of alkali metal hydroxide, the alkali metal chloride solution being obtained from a brine previously purified so as to remove almost all of the impurities which would risk damaging or clogging the membrane during electrolysis.
  • the cell of the "chlor-sodium hydroxide" type used in the process according to the invention is preferably a membrane cell.
  • the membranes are synthetic ion-exchange membranes, preferably made of fluorocarbon polymers capable of withstanding drastic operating conditions, in particular strong alkaline solutions, at high temperatures.
  • flurocarbon polymers are associated with carboxylic and / or sulfonic acid functions, preferably in the form of an alkali metal salt.
  • the fluorocarbon polymers are polytetrafluoroethylenes (PTFE).
  • PTFE polytetrafluoroethylenes
  • the membranes used are obtained by extrusion or rolling of the polymer, and can be reinforced with woven pieces of PTFE fibers.
  • the membranes developed since 1970, have a selectivity at least equal to that of the diaphragms but are much more sensitive to degradation and clogging due to impurities present in the electrolyte.
  • the alkali metal chloride brine is generally prepurified by conventional methods of precipitation and / or adsorption on resins.
  • the alkali metal brine used as an anolyte in the "chlor-sodium hydroxide" type cell preferably comprises between 170 and 315 g / l of alkali metal chloride, preferably between 290 and 310 g / l.
  • this brine is preferably used at a pH of between 2 and 7, advantageously between 2.5 and 4.5.
  • This reaction involves the transfer of two electrons for two molecules of alkali metal chlorides involved.
  • chlorine gas is produced in the anode compartment (2Cl ⁇ ⁇ Cl2 + 2e ⁇ ), and hydrogen gas in the cathode compartment (2H2O + 2e ⁇ 2OH ⁇ + H2).
  • the two alkali metal ions corresponding to the chlorine generated are transferred through the membrane, from the anode compartment to the compartment cathode of the cell type "chlorine-soda" to balance the electric charge due to the simultaneous production of two hydroxyl anions.
  • the formation of chlorine in the anode compartment is therefore accompanied by a drop in concentration of alkali metal chloride in the anolyte simultaneously with an enrichment in alkali metal hydroxide in the cathode compartment.
  • the alkali metal hydroxide solution obtained by electrolysis has a concentration of between 10 and 55% by weight, preferably between 30 and 50% by weight.
  • the chlorine gas and the hydroxide solution produced are free of detectable impurity.
  • hypochlorite obtained will then disproportionate on the one hand into chloride, and on the other hand into alkali metal chlorate according to equation C below (VS) 3 MeClO ⁇ 2 MeCl + MeClO3, Having defined myself previously.
  • the saline solution obtained at the outlet of the slaughter column comprises between 50 and 200 g / l of alkali metal chloride and between 30 and 700 g / l of alkali metal chlorate.
  • this solution saline comprises between 70 and 170 g / l of chloride and between 400 and 650 g / l of alkali metal chlorate.
  • the saline solution before its use as an anolyte in the membrane cell can be advantageously transferred to an evolution tank for a prolonged residence time, at a pH of between 6 and 8, of preferably between 6.5 and 7.
  • the saline solution obtained by the purification process described above is then used as an anolyte in the membrane cell at a pH between 1 and 8, preferably between 2 and 5, and at a temperature between 50 and 100 ° C, advantageously between 70 and 90 ° C.
  • part of the anolyte is recycled to the slaughter column.
  • the alkali metal hydroxide solution obtained by electrolysis in the membrane cell, has a concentration of between 10 and 55% by weight and preferably between 30 and 50% by weight. It is also transferred to the slaughter column.
  • chlorine gas is also produced in the anode compartment.
  • This chlorine is then transferred to the slaughter column, advantageously in admixture with the chlorine gas produced during the electrolysis of the "chlorine-soda" type.
  • anode loop constituted by the anode compartment of the membrane cell and the slaughter column, the products in solution of the electrolysis of the membrane cell being transferred to the slaughter column and vice versa the solution obtained. at the outlet of the slaughter column being used as an anolyte in the membrane cell.
  • the anolyte contains between 50 and 200 g / l of alkali metal chloride and preferably between 70 and 170 g / l.
  • concentration of chlorate leaving the membrane cell necessary for it to be isolable directly by crystallization is easily determined from known crystallization diagrams of water-chloride-chlorate systems (thesis by A. NALLET, Faculty of Sciences of the University of Lyon, Order number 209, defended on January 19, 1955). It is for example between 400 and 650 g / l of anolyte.
  • part of the anolyte after its electrolysis is transferred to a crystallizer or the chlorate is left to crystallize, the mother liquors being recovered and recycled in the anode loop of the membrane cell.
  • the alkali metal used in the process according to the invention is chosen from lithium, sodium and potassium, preferably sodium.
  • the present invention also relates to a device for the preparation of an alkali metal chlorate, implementing the method described above, comprising the combination of a "chlorine-soda" type cell for the preparation of chlorine gas and hydroxide of an alkali metal, of a column for the removal of chlorine by an alkali metal hydroxide, and a membrane cell for the electrolysis of an anolyte comprising a solution of alkali metal chloride and a catholyte comprising a solution of alkali metal hydroxide.
  • FIG. 1 shows a device, used in a preferential manner, and in which the "chlorine-soda" type cell (1) is a membrane cell, comprising one or more anode compartments (11) separated from the cathode compartment (s) (12) corresponding by a membrane (13), the anode compartment or compartments each comprising a suitable device for admitting (111) and recovering (113) the anolyte and a suitable device for recovering chlorine gas (112), the cathode compartment (s) (12) each comprising a suitable device for admitting (121) and recovering (122) the catolyte and a suitable device for removing hydrogen gas (123).
  • the "chlorine-soda" type cell (1) is a membrane cell, comprising one or more anode compartments (11) separated from the cathode compartment (s) (12) corresponding by a membrane (13), the anode compartment or compartments each comprising a suitable device for admitting (111) and recovering (113) the anolyte and a
  • the slaughter column (2) comprises at least one suitable device for admitting an alkali metal hydroxide solution (21) from the cell of the "chlor-sodium hydroxide" type, a suitable device for admitting the chlorine gas (22) and preferably a device (24) for admitting a saline solution poor in chloride and a suitable device (23) for recovering the saline solution obtained.
  • the membrane cell (3) comprises, like the "chlorine-soda” type cell (1) one or more anode compartments (31) separated from the cathode compartment (s) (32) corresponding by a membrane (33), the compartment (s) anodic each comprising a suitable device for admitting saline solution (312), a suitable device for recovering chlorine gas (314) and a device for recovering saline solution after its electrolysis (311).
  • the cathode compartment (s) (32) of this membrane cell (3) include a suitable device for admitting water (321), a suitable device (322) for recovering the catholyte after its electrolysis and a suitable device hydrogen extraction (323).
  • the appropriate device for recovering (313) the anolyte from the membrane cell (3) is connected to a suitable device for introducing this anolyte (24) into the slaughter column (2).
  • the chlorine gas extraction device (314) is also connected to the slaughter column by means of the appropriate chlorine gas intake device (22).
  • anode compartment (31) of the membrane cell (3) is connected either directly by an appropriate means, or by the device for recovering the saline solution after its electrolysis (311) to a crystallizer (4).
  • the crystallizer comprises an appropriate device for recovering mother liquors (43) connected to the anode compartment (31) of the membrane cell (3).
  • the mother liquors can be returned to the level of the anode loop defined above.
  • the alkali metal chlorate obtained enters the final balance of the chlorate preparation according to the invention, it can therefore be considered that it is not an impurity.
  • the chloride solution obtained is practically free from any impurity.
  • impurities harmful to the proper functioning of the membranes, such as calcium, magnesium, strontium, barium, iodine, bromine, aluminum, silica, sulfate, iron, manganese, copper, etc.
  • the present invention also relates to a device for purifying an alkali metal chloride brine, comprising the combination of an electrolysis cell of the "chlor-soda" type (1) and a slaughter column ( 2) chlorine by soda.
  • FIG. 2 shows a cell of the "chlorine-soda" type (1) with a membrane, consisting of one or more anode compartments (11) separated from the cathode compartment (s) (12) corresponding by a membrane (13), the anode compartments each comprising a suitable device for admitting (111) and recovering (113) the anolyte and a suitable device for recovering chlorine gas (112), and the cathode compartment (s) (12) each comprising a suitable device inlet (121) and recovery (122) of the catholyte, and a suitable device for evacuating hydrogen gas (123).
  • the slaughter column (2) comprises at least one suitable device for admitting an alkali metal hydroxide solution (21), a suitable device for admitting chlorine gas, and a suitable device for recovering (23) of a purified solution of alkali metal chloride, the hydroxide inlet devices (21) and chlorine (22) being respectively connected directly to the devices for recovering the catholyte (122) and chlorine gas (112 ) of the "chlorine-soda" type cell (1).
  • the membrane electrolyzer anolyte (3) contains 120 to 150 g / l of NaCl and 450 to 500 g / l of NaClO3.
  • the sodium hydroxide of the catholyte is 32% by weight and the temperature at 90 ° C.
  • the voltage across the electrolyzer is between 3.7 and 3.8 V at 30 A / dm2.
  • the sodium hypochlorite content of the solution recovered at the outlet of the slaughter column (2) is 7.5 to 8 g / l. After its transfer to an evolution tank maintained at 70 ° C, the sodium hypochlorite content is 1 to 2 g / l.
  • the pH is regulated at 6.5 by addition of sodium hydroxide.
  • the cell (3) is supplied by a flow resulting from the reaction between chlorine and the aqueous solution at 33% by weight of soda. This generally leads to the introduction of only 719 kg of water per tonne of NaClO3 produced. There is therefore a saving of 844 kg of water which it would be necessary to evaporate in an installation where the sodium chlorate leaves in the solid state, that is to say where any quantity of incoming water must be evaporated.

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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)
  • Inorganic Chemistry (AREA)
  • Automation & Control Theory (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
EP93401275A 1992-05-20 1993-05-18 Procédé de fabrication de chlorate de métal alcalin et dispositif pour sa mise en oeuvre Ceased EP0571273A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9206112A FR2691479B1 (fr) 1992-05-20 1992-05-20 Procédé de fabrication de chlorate de métal alcalin et dispositif pour sa mise en Óoeuvre.
FR9206112 1992-05-20

Publications (1)

Publication Number Publication Date
EP0571273A1 true EP0571273A1 (fr) 1993-11-24

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ID=9429965

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Application Number Title Priority Date Filing Date
EP93401275A Ceased EP0571273A1 (fr) 1992-05-20 1993-05-18 Procédé de fabrication de chlorate de métal alcalin et dispositif pour sa mise en oeuvre

Country Status (19)

Country Link
EP (1) EP0571273A1 (sh)
JP (1) JPH06158373A (sh)
KR (1) KR930023492A (sh)
CN (1) CN1084584A (sh)
AU (1) AU3868193A (sh)
BR (1) BR9301932A (sh)
CA (1) CA2096588A1 (sh)
CZ (1) CZ95293A3 (sh)
FI (1) FI932299A (sh)
FR (1) FR2691479B1 (sh)
IL (1) IL105718A0 (sh)
MX (1) MX9302943A (sh)
NO (1) NO931798L (sh)
NZ (1) NZ247644A (sh)
PL (1) PL299000A1 (sh)
SK (1) SK49793A3 (sh)
TW (1) TW230848B (sh)
YU (1) YU34493A (sh)
ZA (1) ZA933454B (sh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2718755A1 (fr) * 1993-04-26 1995-10-20 Eka Nobel Ab Procédé de production de chlorate de métal alcalin.

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU657842B2 (en) * 1992-03-13 1995-03-23 Eka Chemicals Oy Method for producing alkaline metal hydroxide
US8216443B2 (en) 2002-07-05 2012-07-10 Akzo Nobel N.V. Process for producing alkali metal chlorate
CN1665961A (zh) * 2002-07-05 2005-09-07 阿克佐诺贝尔公司 生产碱金属氯酸盐的工艺
CN1306068C (zh) * 2002-12-27 2007-03-21 北京化工机械厂 外部自然循环复极式离子膜电解装置
JP4955015B2 (ja) * 2005-12-20 2012-06-20 セラマテック・インク Ｎａイオン伝導セラミックス膜を使用した次亜塩素酸ナトリウム製造の電解プロセス
RU2518899C2 (ru) * 2009-05-15 2014-06-10 Акцо Нобель Кемикалз Интернэшнл Б.В. Активация катода
CN103663380B (zh) * 2013-12-02 2015-04-15 大连高佳化工有限公司 一种氯酸钡生产方法
US20180354789A1 (en) * 2015-08-10 2018-12-13 Showa Denko K.K. Method for producing hydrogen chloride
EP3867422B1 (de) 2018-10-18 2022-03-09 Blue Safety GmbH Elektrochemisches system zur synthese von wässriger oxidationsmittel-lösung

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4405418A (en) * 1980-03-03 1983-09-20 Asahi Kasei Kogyo Kabushiki Kaisha Process for the production of sodium chlorate

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5647265A (en) * 1979-09-25 1981-04-28 Toshiba Corp Production of pure copper casting
JPS575883A (en) * 1980-06-11 1982-01-12 Asahi Chem Ind Co Ltd Installation of sodium chlorate electrolytic tank and chlorine-alkali electrolytic tank installed side by side
JPS57156326A (en) * 1981-03-18 1982-09-27 Toagosei Chem Ind Co Ltd Purification of saline water for electrolysis of alkali chloride
US4702805A (en) * 1986-03-27 1987-10-27 C-I-L Inc. Production of sodium chlorate
FR2655061B1 (fr) * 1989-11-29 1993-12-10 Atochem Fabrication de chlorate ou de perchlorate de metal alcalin.

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4405418A (en) * 1980-03-03 1983-09-20 Asahi Kasei Kogyo Kabushiki Kaisha Process for the production of sodium chlorate

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Week 8244, Derwent Publications Ltd., London, GB; AN 82-94068 & JP-A-57 156 326 (TOA GOSEI CHEM IND LTD) 27 Septembre 1982 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2718755A1 (fr) * 1993-04-26 1995-10-20 Eka Nobel Ab Procédé de production de chlorate de métal alcalin.

Also Published As

Publication number Publication date
NO931798L (no) 1993-11-22
BR9301932A (pt) 1993-11-23
ZA933454B (en) 1994-06-15
FR2691479B1 (fr) 1994-08-19
CZ95293A3 (en) 1993-12-15
FI932299A0 (fi) 1993-05-19
CN1084584A (zh) 1994-03-30
KR930023492A (ko) 1993-12-18
JPH06158373A (ja) 1994-06-07
CA2096588A1 (fr) 1993-11-21
NZ247644A (en) 1994-09-27
FR2691479A1 (fr) 1993-11-26
SK49793A3 (en) 1993-12-08
YU34493A (sh) 1996-02-19
NO931798D0 (no) 1993-05-18
FI932299A (fi) 1993-11-21
PL299000A1 (en) 1993-12-13
IL105718A0 (en) 1993-09-22
TW230848B (sh) 1994-09-21
MX9302943A (es) 1993-12-01
AU3868193A (en) 1993-11-25

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