EP0221685B1 - Procédé électrolytique de production de sels - Google Patents

Procédé électrolytique de production de sels Download PDF

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Publication number
EP0221685B1
EP0221685B1 EP86307734A EP86307734A EP0221685B1 EP 0221685 B1 EP0221685 B1 EP 0221685B1 EP 86307734 A EP86307734 A EP 86307734A EP 86307734 A EP86307734 A EP 86307734A EP 0221685 B1 EP0221685 B1 EP 0221685B1
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EP
European Patent Office
Prior art keywords
anode
metal
anolyte
cathode
cell
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
Application number
EP86307734A
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German (de)
English (en)
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EP0221685A1 (fr
Inventor
Brian Surfleet
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.)
Electricity Association Services Ltd
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Electricity Association Services Ltd
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Filing date
Publication date
Application filed by Electricity Association Services Ltd filed Critical Electricity Association Services Ltd
Publication of EP0221685A1 publication Critical patent/EP0221685A1/fr
Application granted granted Critical
Publication of EP0221685B1 publication Critical patent/EP0221685B1/fr
Expired 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

Definitions

  • the present invention relates to an electrolytic process for the manufacture of salts.
  • salts i.e. the chemical compounds formed by metal ions and acid/alkali anions
  • the simplest routes have been selected, for example those metals which are readily and easily attacked by the acids or alkalis to form salts are well known, e.g. Zn + 2HCl ⁇ ZnCl2 + H2
  • synthetic routes via metal containing compounds are preferred, e.g. CuO + H2SO4 ⁇ CuSO4 + H2O
  • the use of a compound containing a metal for salt formation is always more expensive than the use of the metal itself and a direct route is therefore economically preferable.
  • the direct route is not thermodynamically favoured and aggresive reaction conditions such as high temperatures and pressures and long reaction times are often required. These processes become expensive in energy, time and capital costs.
  • the present invention provides a process for the manufacture of a salt of a metal selected from copper, cobolt, silver, tin or nickel, which process comprises passing an electric current through an electrolytic cell comprising an anode formed from or containing the said metal, a cathode, an anolyte which will provide the anions to form the salt and a catholyte, the anode and the cathode being separated by a microporous plastics separator which has a pore size in the range of from 0.01 to 10 microns and a pore volume in the range of from 45 to 55%.
  • the metal which forms the anode loses electrons to give metal ions, e.g. M2+ by one reaction M - 2e ⁇ M2+
  • metal ions e.g. M2+ by one reaction M - 2e ⁇ M2+
  • These ions exist either as totally ionised metal ions together with the corresponding anions A2 ⁇ , or in an equlibrium The position of this equilibrium depends upon the temperature, metal ion concentration, pH etc.
  • the anode may comprise one of the following:
  • the cathode used in the process of the present invention remains inert and since in general some of the metal will pass through the separator and coat the cathode it is preferred to use a cathode of the metal concerned, although a cathode of another metal may also be used.
  • a cathodic reaction takes place at the cathode, for example the production of hydrogen by the reduction of the acid cation: 2H+ + 2e ⁇ H2
  • the anolyte is an electrolyte which contains ions that will conduct electricity, which provides the anions so as to form the metal salt, and in which the metal salt produced in the process of the invention is reasonably soluble.
  • the anolyte may be an acid, such as sulphuric acid, hydrochloric acid, nitric acid, acetic acid, or an alkali, such as sodium or potassium hydroxide, or ammonium hydroxide.
  • the catholyte may comprise any electrolyte, but the preferred catholyte is an electrolyte which is the same as the anolyte, but not necessarily at the same concentration.
  • the process of the present invention is suitable for the production of many metal salts and, in particular, salts of cobalt, nickel and tin.
  • Specific examples of salts which may be prepared by the process of the invention are stannous sulphate, silver nitrate, copper acetate, cobalt chloride and cobalt acetate.
  • the temperature, concentration and current density employed in the process of the invention depend upon the reaction which is being carried out.
  • the microporous plastics separator used in the process of the present invention preferably has a pore size in the range of from 0.01 to 0.1 microns and a pore volume of about 50%.
  • the porosity or pore volumne controls the electrical resistance of the separator, whilst the pore size influences the transport of ions across the separator.
  • the microporous plastics separator should be chemically resistant to its environment at the operating temperature and the operating pH. It should also be made from a plastics material which is wettable, or which can be treated to render it wettable, and possesses sufficient mechanical strength so that it is capable of being engineered into an appropriate support.
  • microporous plastics separator is a filled polyethylene separator sold under the Trade Name DARAMIC® (W.R. Grace & Co.), an irradiated polyethylene separator sold by Raychem, a microporous polyolefin manufactured by Schumacher, a compound called GORTEX® which is a microporous polytetrafluoroethylene and a product called VYON/PORVAIR® which is a microporous high density polyethylene.
  • the separator is usually fabricated onto a support frame, for example by means of an adhesive or by thermal or ultrasonic welding.
  • a support frame enables the separator to be mounted in a cell and provides some support to the separator against bulging which is particularly important for those materials which expand when wet and bulge.
  • any two or three compartment cell may be used in the present invention.
  • the cell should preferably have a symmetrical design so that the anode is attacked from both sides at an equal rate.
  • the electrodes may be suspended in the cell from appropriate hooks e.g. of titanium, from lugs cast onto the electrode or by bolting the electrodes onto an appropriate bus bar.
  • the process of the present invention may be a continuous or a batch process.
  • some pumping of the electrolytes will be required but it is preferable to use external pumps so as not to interfere with the cell symmetry.
  • heating it is preferred that it is either external or that electrically controlled heating elements are positioned at the sides of the anode and cathode compartments of the cell.
  • the volume of the anolyte depends mainly upon the throughput required and thus is generally related to the product requirement, the stability of the product and the size of any ancillary equipment used for working up and extracting the product.
  • the volume of the catholyte is preferably the same as that of the anolyte since it is preferred to use the catholyte to replace the anolyte on completion of the reaction.
  • the anode area should be as large as possible, providing that the available area of microporous plastics separator can pass the current required having regard to the optimum current density required for the process.
  • the cathode area is preferably chosen to be one of two extremes. Either the surface area is large and the current density is kept low so that any metal ions penetrating to the cathode compartment are electrodeposited onto the cathode, or the surfaces are small and the current density is kept high and hydrogen evolution prevents much of the metal being deposited on the cathode.
  • a filter press type cell is particularly useful for carrying out the process of the invention in a continuous manner. It is possible to alter the rate of flow through the cell and the current density so that a solution of the metal salt is produced which has an appropriate concentration of the metal salt therein. The metal salt solution produced may in some instances be used without further processing in a conventional chemical process. Carrying out the process of the present invention continuously using a filter press type cell is advantageous if a relatively unstable metal salt is produced since the process time is minimized and this helps to avoid disintegration of the unstable salt.
  • the separator When a granular anode is used in the process of the invention it is preferred for the separator to surround the anode basket. In this arrangement the cell does not have separate compartments. The volume of anolyte required is thus considerably reduced since it is equal to the volume of the basket surrounded by the separator minus the volume of the granulated metal.
  • the anolyte is pumped into and out of each anode basket surrounded by separator, for example by means of a pipe which extends into the basket. It is thus possible using this arrangment for the metal salt solution to be removed from the cell at regular intervals, i.e. in a semi-continuous manner.
  • anodes 1 are placed in the central compartment 6 of a five compartment cell.
  • the anodes are hung from the anode rail 2.
  • middle compartments 8 which do not contain any electrodes.
  • the middle compartments 8 are separated from the anode compartment by separators 5 of a microporous plastics material.
  • cathode compartments 7 which are separated from the middle compartments by separators 5 of a microporous plastics material.
  • the cathode compartments 7 contain cathodes 3 which are suspended from cathode rails 4.
  • the compartments 6, 7 and 8 are filled with the appropriate electrolyte and the current switched on and adjusted to the required current density.
  • the metal ion concentration in compartment 6 builds up and as the anodes 1 corrode they are replaced by fresh anodes.
  • the anodes are preferably replaced in sequence as this permits a realistic amount of the anode area to be used and hence a reasonable current density to be used. If an appreciable amount of the metal, say 7 to 10%, has been coated onto the cathode, then the cathode may be hung on the anode rail to function as an anode until the coating has redissolved.
  • the anodes When the metal salt produced in compartment 6 reaches a level where extraction is viable, the anodes are removed from the compartment, the anolyte pumped out of the cell and the anolyte replaced either by fresh electrolyte which is generally the electrolyte from compartments 7 or 8, if necessary augmented with further chemicals.
  • compartment 6 The anodes in compartment 6 are replaced, all of the compartments 6, 7, and 8 are topped up with electrolyte, as necessary, and the cell switched on for the process to recommence.
  • a tin anode was dissolved in 2N sulphuric acid in a two compartment cell having a microporous polyethylene separator separating the anode and cathode compartments which both had a volume of 2.5l (total cell volume 5l).
  • the cell was operated under the following conditions: Anode Current Density 15 mA/cm2 Cathode Current Density 60 mA/cm2 Temperature Ambient Initial Sulphuric Acid Concentration 2N Final Concentration of Tin as Stannous ion 100 g/l Weight loss of Tin Anode 270.5g Anode Current efficiency 98% Metal Transfer to Catholyte 15 g
  • a tin anode was dissolved in 2N sulphuric acid in a two compartment cell having a filled microporous polyethylene separator separating the anode and cathode compartments.
  • the cell had a total volume of 20l (7l anolyte and 13l catholyte).
  • the cell was operated under the following conditions: Anode Current Density 15 mA/cm2 Cathode Current Density 15 mA/cm2 Temperature Ambient Initial Sulphuric Acid Concentration 2N Final Concentration of Tin as Stannous ion 160 g/l Weight loss of Tin Anode 1150 g Anode Current efficiency 98% Metal Transfer to Catholyte 30 g Final Sulphuric Acid Concentration 0.1 N
  • a silver anode was dissolved in 1N nitric acid in a three compartment cell having a filled microporous polyethylene separators separating the compartments thereof.
  • the anode and cathode compartments of the cell both had volumes of 0.5l.
  • the cell was operated under the following conditions: Anode Current Density 40 mA/cm2 Cathode Current Density 10 mA/cm2 Temperature Ambient Initial Nitric Acid Concentration 1N Final Concentration of Silver in Anolyte 40 g/l Weight loss of Silver Anode 21 g Anode Current efficiency 98% Final Concentration of free Nitric acid 0.52 N
  • Cobalt chips were placed in a titanium anode basket in 5N hydrochloric acid in a two compartment cell having a filled microporous polyethylene separator separating the anode and cathode compartments which both had a volume of 1.0l (total cell volume 2l).
  • the cell was operated under the following conditions: Anode Current Density 30 mA/cm2 Cathode Current Density 20 mA/cm2 Temperature 35 o C Initial Sulphuric Acid Concentration 5N Final Concentration of Cobalt in the Anolyte 192.3 g/l Weight loss of Cobalt Anode 196 g Anode Current efficiency 98% Metal transfer to Catholyte 2.5 g
  • a copper anode was dissolved in 2N acetic acid in a two compartment cell having a filled microporous polyethylene separator separating the anode and cathode compartments which both bad a volume of 0.5l. (total cell volume 1l).
  • the cell was operated under the following conditions: Anode Current Density 20 mA/cm2 Cathode Current Density 20 mA/cm2 Temperature 10 o C Initial Acetic Acid Concentration 2N Final Concentration of Copper in the anolyte 41 g/l
  • a copper anode was dissolved in a mixture of 4M ammonium hydroxide and 1M ammonium nitrate in a two compartment cell having a polyethylene separator sold under the Trade Name DARAMIC separating the anode and cathode compartments.
  • the cell was operated under the following conditions: Anode Current Density 25mA/cm2 Temperature 25 o C Initial pH of anolyte pH 10 Concentration of copper as cupric ion in anolyte 33 g/l Anode Current Efficiency 98%
  • a copper anode was dissolved in a mixture of 2M sodium pyrophosphate, 0.5M sodium nitrate and 0.1M ammonium hydroxide in a two compartment cell having a filled microporous polyethylene separator separating the anode and cathode compartments.
  • the cell was operated under the following conditions: Anode Current Density 5mA/cm2 Temperature 25 o C Initial pH of anolyte pH 10 Concentration of copper as cupric ion in anolyte 25 g/l Anode Current Efficiency 99%
  • a tin anode was dissolved in 3N sodium or potassium hydroxide in a two compartment cell having a microporous polytetrafluoroethylene separator sold under the name of GORTEX separating the anode and cathode compartments.
  • the separator had previously been rendered wettable by immersion in methanol for about 1 hour.
  • the cell was operated under the following conditions: Final Anode Current Density 20mA/cm2 Temperature 60-90 o C Initial pH of anolyte 13 Concentration of tin as stannous ion in anolyte 55 g/l Anode Current Efficiency 99% The above run was repeated under the same conditions using a similarly wetted microporous polytetrafluoroethylene manufactured by Doulton Industrial Products Limited. Similar results were obtained. It will be understood by those skilled in the art that the process of the present invention cannot be used to produce salts where the acid/alkali starting material would attack the separator e.g. hydrogen fluoride would attack the microporous plastics separator.
  • the process also cannot be used to produce insoluble salts unless other means, such as periodic renewal, rotation of the anode or mechanical clearing is carried out since the anode would rapidly become coated with the insoluble product thereby causing the cell voltage to rise and the process to stop.
  • the process furthermore cannot be used where the product is thermodynamically unstable under the cell operating conditions or where the anode is rendered passive by the acid/alkali starting material.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (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)

Claims (14)

  1. Un procédé de fabrication d'un sel d'un métal choisi parmi le cuivre, le cobalt, l'argent, l'étain ou le nickel, procédé qui comprend le passage d'un courant electrique à travers une cellule électrolytique comprenant une anode formée dudit métal ou contenant celui-ci, une cathode, un anolyte qui fournit les anions pour former le sel et un catholyte, l'anode et la cathode étant séparées par un séparateur en plastique microporeux dont la dimension de pore est dans la plage comprise entre 0,01 et 10 µm (micron) et dont le volume de pore est dans la plage comprise entre 45 et 55%.
  2. Un procédé selon la revendication 1 dans lequel l'anode est un lingot du métal dont le sel doit être produit.
  3. Un procédé selon la revendication 1 dans lequel l'anode est constituée de métal en granules ou tes pièces de rebut du métal dont le sel doit être produit.
  4. Un procédé selon la revendication 1 dans lequel l'anode est une anode insoluble.
  5. Un procédé selon la revendication 1 dans lequel l'anode comprend des échantillons en granules ou en particules de métaux mélangés.
  6. Un procédé selon l'une quelconque des revendications précédentes dans lequel la cathode est formée du métal dont le sel doit être produit.
  7. Un procédé selon l'une quelconque des revendications précédentes dans lequel l'anolyte est un acide.
  8. Un procédé selon la revendication 7 dans lequel l'acide est l'acide sulfurique, l'acide chlorhydrique, l'acide nitrique ou l'acide acétique.
  9. Un procédé selon l'une quelconque des revendications 1 à 6 dans lequel l'anolyte est un alcali.
  10. Un procédé selon la revendication 9 dans lequel l'alcali est l'hydroxyde de sodium, l'hydroxyde de potassium ou l'hydroxyde d'ammonium.
  11. Un procédé selon l'une quelconque des revendications précédentes dans lequel le catholyte est un électrolyte qui est le même que l'anolyte.
  12. Un procédé selon l'une quelconque des revendications précédentes dans lequel la dimension de pore du séparateur en plastique microporeux est dans la plage comprise entre 0.01 à 0,1 µm (micron) et son volume de pore est d'environ 50%.
  13. Un procédé selon l'une quelconque des revendications précédentes dans lequel le séparateur en plastique microporeux est constitué d'une matière plastique qui est mouillable ou qui peut être traitée pour la rendre mouillable.
  14. Un procédé selon l'une quelconque des revendications précédentes qui est mis en oeuvre de manière continue ou semi-continue.
EP86307734A 1985-10-08 1986-10-07 Procédé électrolytique de production de sels Expired EP0221685B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8524784A GB2181158B (en) 1985-10-08 1985-10-08 Electrolytic process for the manufacture of salts
GB8524784 1985-10-08

Publications (2)

Publication Number Publication Date
EP0221685A1 EP0221685A1 (fr) 1987-05-13
EP0221685B1 true EP0221685B1 (fr) 1992-04-15

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EP86307734A Expired EP0221685B1 (fr) 1985-10-08 1986-10-07 Procédé électrolytique de production de sels

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DE (1) DE3684872D1 (fr)
GB (1) GB2181158B (fr)

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RU2150531C1 (ru) * 1999-02-02 2000-06-10 Дагестанский государственный университет Способ получения углекислых солей металлов
FI124812B (fi) * 2010-01-29 2015-01-30 Outotec Oyj Menetelmä ja laitteisto metallipulverin valmistamiseksi
JP7275629B2 (ja) * 2018-05-16 2023-05-18 住友金属鉱山株式会社 硫酸溶液の製造方法
KR20250010132A (ko) 2018-08-02 2025-01-20 테슬라, 인크. 전기화학적 용해를 통한 금속 황산염 제조 시스템

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1788512A (en) * 1927-05-09 1931-01-13 Magnetic Pigment Company Electrolysis
US2288503A (en) * 1940-11-02 1942-06-30 Int Smelting & Refining Co Electrolytic basic metal chromate pigment manufacture
AT279554B (de) * 1968-01-22 1970-03-10 Ruthner Ind Planungs Ag Verfahren und Vorrichtung zur Herstellung von Metallsalzlösungen elektrochemisch edler Metalle
US3795595A (en) * 1971-07-29 1974-03-05 Vulcan Materials Co Electrolytic production of tin and lead salts using anion permselective membranes
JPS5210667B2 (fr) * 1973-06-07 1977-03-25
DE2602031C2 (de) * 1976-01-21 1977-12-15 Th. Goldschmidt Ag, 4300 Essen Verfahren zur Herstellung von Zinnll-sulfat
US4067788A (en) * 1976-09-20 1978-01-10 Electromedia, Inc. Electrochemical production of finely divided metal oxides, metal hydroxides and metals
AU524460B2 (en) * 1978-08-11 1982-09-16 Asahi Kasei Kogyo Kabushiki Kaisha Microporous film
ATE24550T1 (de) * 1980-01-29 1987-01-15 Atochem Diaphragma fuer die elektrolyse und verfahren zu seiner herstellung.

Also Published As

Publication number Publication date
GB8524784D0 (en) 1985-11-13
EP0221685A1 (fr) 1987-05-13
GB2181158B (en) 1989-11-15
DE3684872D1 (de) 1992-05-21
GB2181158A (en) 1987-04-15

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