EP1458906A2 - Electrochemical process for preparation of zinc metal - Google Patents

Electrochemical process for preparation of zinc metal

Info

Publication number
EP1458906A2
EP1458906A2 EP02785828A EP02785828A EP1458906A2 EP 1458906 A2 EP1458906 A2 EP 1458906A2 EP 02785828 A EP02785828 A EP 02785828A EP 02785828 A EP02785828 A EP 02785828A EP 1458906 A2 EP1458906 A2 EP 1458906A2
Authority
EP
European Patent Office
Prior art keywords
electrochemical process
zinc
electrochemical
zinc oxide
solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02785828A
Other languages
German (de)
French (fr)
Inventor
Baldev Kumar Bandlish
Vincent Wise Martin
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.)
Clariant International Ltd
Original Assignee
Clariant International Ltd
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 Clariant International Ltd filed Critical Clariant International Ltd
Publication of EP1458906A2 publication Critical patent/EP1458906A2/en
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C5/00—Electrolytic production, recovery or refining of metal powders or porous metal masses
    • C25C5/02—Electrolytic production, recovery or refining of metal powders or porous metal masses from solutions
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
    • C25C1/16—Electrolytic production, recovery or refining of metals by electrolysis of solutions of zinc, cadmium or mercury

Definitions

  • the present invention provides an electrochemical process for the preparation of zinc metal.
  • Zinc powder is widely used in the chemical industry in various industries. Zinc oxide containing other zinc salts, metal impurities, etc. is produced as a byproduct. Recycling of the zinc oxide to produce pure zinc powder is highly desirable from a cost as well as an environmental point of view.
  • the electrodeposition of zinc metal is a well-known reaction in electrochemical technology (See, for example, D. Pletcher and F.C. Walsh, Industrial Electrochemistry, Blackie Academic, 1993).
  • the electrogalvanizing of steel is a process carried out on a very large scale and aqueous acid is the normal medium.
  • High speed, reel to reel galvanizing of steel is carried out in sulfuric acid with dimensionally stable anodes and uniform deposition is achieved at high current density by inducing very efficient mass transport by rapid movement of the steel surface.
  • the deposition of zinc metal is also the critical electrode reaction in the electrowinning and electrorefining of zinc.
  • Zinc metal can be produced by electrolysis either in strong alkaline or neutral zinc containing solutions.
  • the first patents obtained on the alkaline electrolysis process date back to the early thirties (German Patents, 581013, 506590, 653557). In these methods, a low current density of 1200-1500 amperes/sq. meter (Mm 2 ) was used. Volume efficiency and current density of these batch type processes are too low to be industrially attractive.
  • I. Orszagh and B. Vass Hung. J. Ind. Chem., 13, (1985) 287) used these methods to recycle zinc oxide byproduct from zinc dithionite production. There is at present a need to carry out an electrolysis reaction to produce zinc metal under conditions where corrosion of the electrodes is minimized.
  • the present invention fulfils this and other needs.
  • the present invention provides a low corrosion electrochemical process for preparing zinc metal wherein air or nitrogen is bubbled in during the electrochemical reduction process producing the zinc metal. It has been unexpectedly found that bubbling of air or nitrogen reduces electrode corrosion during the electrochemical process.
  • U.S. Patent No. 5,958,210 discloses a method for electrowinning metallic zinc from zinc ion in aqueous solution, said method comprising performing electrolysis on a mixture of solid conductive particles and aqueous alkali solution, said solution ranging in concentration from about 3N to about 20N alkali and containing dissolved zinc ion at an initial concentration ranging from about 50 to about 500 grams of zinc ion per liter of said solution, in an electrolytic cell containing first and second vertically arranged, parallel flat plates defined as a current feeder and a counter electrode, respectively, said counter electrode coated with a substance that is catalytic for oxygen evolution, said cell further containing an ion-permeable diaphragm parallel to each of said plates and interposed therebetween to define a gap between said current feeder and said diaphragm, by passing said mixture of particles and solution through said gap such that said particles contact said current feeder and passing a current across said gap, thereby depositing metallic zinc from said solution onto said particles.
  • U.S. Patent Application serial number 09/776,518 discloses an electrochemical process for preparing zinc powder which involves: a) providing to an electrochemical cell a basic solution of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, the basic solution prepared by dissolving the zinc oxide or the other zinc compound in an aqueous 2.5 to 10.0 M base solution; and b) passing current to the cell at a current density of about 10,000 to about 40,000 A/m 2 for a time period sufficient to electrochemically reduce the zinc oxide to zinc powder, wherein the electrochemical process has a current efficiency of at least 70% and is substantially free from electrode corrosion.
  • U.S. Patent Application serial number 09/776,644 discloses a continuous electrochemical process for preparing zinc powder which involves: providing to an electrochemical cell a solution or suspension in an aqueous 1.25 Molar to 10.0 Molar base solution of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, the solution or suspension containing at least 2 millimoles of solubilized zinc based species per 100 grams of electrolyte; and b) passing current to the cell at a current density of about 500 to 40,000 A/m 2 , for a time period sufficient to electrochemically reduce the solubilized zinc based species to zinc powder, while continuously or intermittently adding a sufficient amount of the zinc oxide or the other zinc compound to the cell to maintain the concentration of the solubilized zinc based species at a level of at least 2 millimoles per 100 grams of electrolyte and continuously or intermittently removing at least a portion of the zinc powder formed; wherein the electrolyte includes the aqueous 1.25 Molar to
  • the present invention provides a low corrosion electrochemical process for preparing zinc metal which comprises electrochemically reducing an aqueous basic solution or slurry of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, wherein the electrochemical process is carried out in an undivided electrochemical cell, and wherein air or nitrogen is bubbled in through the solution or slurry of zinc oxide or said other zinc compound during said electrochemical process.
  • the present invention provides a low corrosion electrochemical process for preparing zinc metal which comprises electrochemically reducing an aqueous basic solution or slurry of zinc oxide or any other zinc compound (such as zinc sulfate) that reacts with an aqueous base to produce zinc oxide, wherein the electrochemical process is carried out in an undivided electrochemical cell, and wherein air or nitrogen is bubbled in through the solution or slurry of zinc oxide or said other zinc compound during said electrochemical process.
  • any other zinc compound such as zinc sulfate
  • the anode may be made from any conventional suitable material such as platinum, or iridium, either of which may be coated over an inert support such as niobium or titanium.
  • the anode may also be made of nickel, or from conventional materials having good alkali corrosion resistance, e.g., lead or stainless steel.
  • the cathode may be made from any conventional suitable materials having good alkali corrosion resistance, such as magnesium, magnesium alloy, copper, lead and stainless steel.
  • the anode in the present invention is formed of stainless steel or nickel and the cathode is formed of stainless steel, magnesium, magnesium alloy or copper.
  • the cathode and the anode are stainless steel and copper respectively, and in one embodiment nickel and copper respectively.
  • aqueous base solutions employed in the process of the invention are prepared by combining water with a source of alkali metal or alkaline earth metal ions, such as lithium, sodium, and potassium, and a source of hydroxyl (OH " ions).
  • a source of alkali metal or alkaline earth metal ions such as lithium, sodium, and potassium
  • OH " ions hydroxyl
  • a single source may of course provide both types of ions.
  • the various alkali or alkaline earth metal ions are preferably supplied from various compounds such as hydroxides and oxides.
  • Preferred base solutions are sodium and potassium hydroxide solutions.
  • temperatures higher than ambient are generally desired because of the beneficial effects on the kinetics of all steps in an electrode process.
  • the diffusion coefficient, the exchange current density and the rates of chemical reactions generally are increased.
  • the decrease in viscosity and increase in diffusion coefficient leads to the increased mass transport rates.
  • This increased mass transport of zinc ions from the bulk of the solution to the cathodic region is highly desirable.
  • increase in the rate of chemical reaction such as the oxidation of zinc produced with oxygen and mass transport of the byproduct oxygen to the bulk of the solution may not be desirable.
  • higher than ambient temperatures are found to be favorable for the electrolytic reduction of zinc oxide to zinc, and are preferred.
  • the presently claimed electrochemical reduction process is conducted at a temperature of from 10°C to 105°C, preferably from 40° to 80°C, and more preferably from 60° to 75°C.
  • the electrochemical process of the present invention is a continuous process.
  • continuous in the present context is well understood by one of ordinary skill in the art.
  • it relates a process wherein zinc oxide or the other zinc compound can be added continuously to the electrochemical cell and at least a portion of the zinc metal formed is removed continuously or intermittently during the electrochemical process.
  • a continuous electrochemical process has been disclosed in U.S. Application serial number 09/776,664 (filed February 2, 2001).
  • a resin Kettle (5 inch in diameter and 18 inch high) is used as the cell.
  • a solution or slurry of zinc oxide in the aqueous sodium hydroxide solution (3 to 3.5 liters) at 20 to 80°C is charged into the resin kettle.
  • a thermometer, desired cathodes and anodes are positioned in the cell using laboratory clamps. Mixing is achieved by bubbling air or nitrogen through the solution or slurry of ZnO. In some experiments mechanical stirring in addition to bubbling of air or nitrogen is used. Control experiments use only mechanical stirring for mixing (no air or nitrogen bubbling). Parts of the cathode and anode surfaces are covered with Teflon tape to achieve the desired active cathode and anode surface areas.
  • Electrolysis is carried out at a current density of about 5000 Amps/m 2 . A portion of the zinc deposited on the cathode is removed periodically. At the end of the experiment, zinc particles are separated from the electrolyte by decantation, washed with water and then dried. Dried zinc particles were analyzed to determine the zinc content.
  • All slurry based electrolysis contained undissolved ZnO in the electrolyte during the entire electrolysis.
  • Zn particles deposited on the copper cathode were easily removable.
  • the precision of the corrosion results is about ⁇ 1g/45.5 kg Zn (the values expressed in g/45.5 kg Zn are normalized values).

Landscapes

  • 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 Metals (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)

Abstract

Disclosed is a low corrosion electrochemical process for preparing zinc metal which comprises electrochemically reducing an aqueous basic solution or slurry of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, wherein the electrochemical process is carried out in an undivided electrochemical cell, and wherein air or nitrogen is bubbled in through the solution or slurry of zinc oxide or said other zinc compound during said electrochemical process.

Description

ELECTROCHEMICAL PROCESS FOR PREPARATION OF ZINC METAL
FIELD OF THE INVENTION The present invention provides an electrochemical process for the preparation of zinc metal.
BACKGROUND OF THE INVENTION Zinc powder is widely used in the chemical industry in various industries. Zinc oxide containing other zinc salts, metal impurities, etc. is produced as a byproduct. Recycling of the zinc oxide to produce pure zinc powder is highly desirable from a cost as well as an environmental point of view.
The electrodeposition of zinc metal is a well-known reaction in electrochemical technology (See, for example, D. Pletcher and F.C. Walsh, Industrial Electrochemistry, Blackie Academic, 1993). The electrogalvanizing of steel is a process carried out on a very large scale and aqueous acid is the normal medium. High speed, reel to reel galvanizing of steel is carried out in sulfuric acid with dimensionally stable anodes and uniform deposition is achieved at high current density by inducing very efficient mass transport by rapid movement of the steel surface. The deposition of zinc metal is also the critical electrode reaction in the electrowinning and electrorefining of zinc. In addition, there are a number of technologies, which have been demonstrated for the removal of Zn(ll) from effluents. However, in these technologies, concentration of Zn(ll) is low, commonly less than 100 ppm. Finally, the deposition of zinc has been widely investigated as the cathodic reaction in candidate secondary batteries. In all these applications, however, the objective is to select the conditions so as to give an adhesive and smooth zinc coating.
Zinc metal can be produced by electrolysis either in strong alkaline or neutral zinc containing solutions. The first patents obtained on the alkaline electrolysis process date back to the early thirties (German Patents, 581013, 506590, 653557). In these methods, a low current density of 1200-1500 amperes/sq. meter (Mm2) was used. Volume efficiency and current density of these batch type processes are too low to be industrially attractive. I. Orszagh and B. Vass (Hung. J. Ind. Chem., 13, (1985) 287) used these methods to recycle zinc oxide byproduct from zinc dithionite production. There is at present a need to carry out an electrolysis reaction to produce zinc metal under conditions where corrosion of the electrodes is minimized. The present invention fulfils this and other needs. The present invention provides a low corrosion electrochemical process for preparing zinc metal wherein air or nitrogen is bubbled in during the electrochemical reduction process producing the zinc metal. It has been unexpectedly found that bubbling of air or nitrogen reduces electrode corrosion during the electrochemical process.
U.S. Patent No. 5,958,210 discloses a method for electrowinning metallic zinc from zinc ion in aqueous solution, said method comprising performing electrolysis on a mixture of solid conductive particles and aqueous alkali solution, said solution ranging in concentration from about 3N to about 20N alkali and containing dissolved zinc ion at an initial concentration ranging from about 50 to about 500 grams of zinc ion per liter of said solution, in an electrolytic cell containing first and second vertically arranged, parallel flat plates defined as a current feeder and a counter electrode, respectively, said counter electrode coated with a substance that is catalytic for oxygen evolution, said cell further containing an ion-permeable diaphragm parallel to each of said plates and interposed therebetween to define a gap between said current feeder and said diaphragm, by passing said mixture of particles and solution through said gap such that said particles contact said current feeder and passing a current across said gap, thereby depositing metallic zinc from said solution onto said particles.
U.S. Patent Application serial number 09/776,518 (filed February 2, 2001) discloses an electrochemical process for preparing zinc powder which involves: a) providing to an electrochemical cell a basic solution of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, the basic solution prepared by dissolving the zinc oxide or the other zinc compound in an aqueous 2.5 to 10.0 M base solution; and b) passing current to the cell at a current density of about 10,000 to about 40,000 A/m2 for a time period sufficient to electrochemically reduce the zinc oxide to zinc powder, wherein the electrochemical process has a current efficiency of at least 70% and is substantially free from electrode corrosion.
U.S. Patent Application serial number 09/776,644 (filed February 2, 2001) discloses a continuous electrochemical process for preparing zinc powder which involves: providing to an electrochemical cell a solution or suspension in an aqueous 1.25 Molar to 10.0 Molar base solution of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, the solution or suspension containing at least 2 millimoles of solubilized zinc based species per 100 grams of electrolyte; and b) passing current to the cell at a current density of about 500 to 40,000 A/m2, for a time period sufficient to electrochemically reduce the solubilized zinc based species to zinc powder, while continuously or intermittently adding a sufficient amount of the zinc oxide or the other zinc compound to the cell to maintain the concentration of the solubilized zinc based species at a level of at least 2 millimoles per 100 grams of electrolyte and continuously or intermittently removing at least a portion of the zinc powder formed; wherein the electrolyte includes the aqueous base solution and the zinc oxide or the other zinc compound.
SUMMARY OF THE INVENTION The present invention provides a low corrosion electrochemical process for preparing zinc metal which comprises electrochemically reducing an aqueous basic solution or slurry of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, wherein the electrochemical process is carried out in an undivided electrochemical cell, and wherein air or nitrogen is bubbled in through the solution or slurry of zinc oxide or said other zinc compound during said electrochemical process.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a low corrosion electrochemical process for preparing zinc metal which comprises electrochemically reducing an aqueous basic solution or slurry of zinc oxide or any other zinc compound (such as zinc sulfate) that reacts with an aqueous base to produce zinc oxide, wherein the electrochemical process is carried out in an undivided electrochemical cell, and wherein air or nitrogen is bubbled in through the solution or slurry of zinc oxide or said other zinc compound during said electrochemical process.
The anode may be made from any conventional suitable material such as platinum, or iridium, either of which may be coated over an inert support such as niobium or titanium. The anode may also be made of nickel, or from conventional materials having good alkali corrosion resistance, e.g., lead or stainless steel. The cathode may be made from any conventional suitable materials having good alkali corrosion resistance, such as magnesium, magnesium alloy, copper, lead and stainless steel. Preferably, the anode in the present invention is formed of stainless steel or nickel and the cathode is formed of stainless steel, magnesium, magnesium alloy or copper. In one embodiment, the cathode and the anode are stainless steel and copper respectively, and in one embodiment nickel and copper respectively.
The aqueous base solutions employed in the process of the invention are prepared by combining water with a source of alkali metal or alkaline earth metal ions, such as lithium, sodium, and potassium, and a source of hydroxyl (OH" ions). A single source may of course provide both types of ions. The various alkali or alkaline earth metal ions are preferably supplied from various compounds such as hydroxides and oxides. Preferred base solutions are sodium and potassium hydroxide solutions.
For electrolysis, temperatures higher than ambient are generally desired because of the beneficial effects on the kinetics of all steps in an electrode process. At higher temperatures, the diffusion coefficient, the exchange current density and the rates of chemical reactions generally are increased. The decrease in viscosity and increase in diffusion coefficient leads to the increased mass transport rates. This increased mass transport of zinc ions from the bulk of the solution to the cathodic region is highly desirable. However, increase in the rate of chemical reaction such as the oxidation of zinc produced with oxygen and mass transport of the byproduct oxygen to the bulk of the solution may not be desirable. In the present invention, higher than ambient temperatures are found to be favorable for the electrolytic reduction of zinc oxide to zinc, and are preferred.
In one embodiment, the presently claimed electrochemical reduction process is conducted at a temperature of from 10°C to 105°C, preferably from 40° to 80°C, and more preferably from 60° to 75°C.
In one embodiment, the electrochemical process of the present invention is a continuous process. The meaning of "continuous" in the present context is well understood by one of ordinary skill in the art. As used herein, it relates a process wherein zinc oxide or the other zinc compound can be added continuously to the electrochemical cell and at least a portion of the zinc metal formed is removed continuously or intermittently during the electrochemical process. A continuous electrochemical process has been disclosed in U.S. Application serial number 09/776,664 (filed February 2, 2001).
The following specific examples will provide detailed illustrations of the methods of producing and utilizing compositions of the present invention. These examples are not intended, however, to limit or restrict the scope of the invention in any way and should not be construed as providing conditions, parameters or values which must be utilized exclusively in order to practice the present invention. Unless otherwise specified, all parts and percents are by weight.
EXAMPLES
EXAMPLE 1 General procedure used for electrolytic reduction of zinc oxide to zinc metal
In these experiments, a resin Kettle (5 inch in diameter and 18 inch high) is used as the cell. A solution or slurry of zinc oxide in the aqueous sodium hydroxide solution (3 to 3.5 liters) at 20 to 80°C is charged into the resin kettle. A thermometer, desired cathodes and anodes are positioned in the cell using laboratory clamps. Mixing is achieved by bubbling air or nitrogen through the solution or slurry of ZnO. In some experiments mechanical stirring in addition to bubbling of air or nitrogen is used. Control experiments use only mechanical stirring for mixing (no air or nitrogen bubbling). Parts of the cathode and anode surfaces are covered with Teflon tape to achieve the desired active cathode and anode surface areas. Electrolysis is carried out at a current density of about 5000 Amps/m2. A portion of the zinc deposited on the cathode is removed periodically. At the end of the experiment, zinc particles are separated from the electrolyte by decantation, washed with water and then dried. Dried zinc particles were analyzed to determine the zinc content.
EXAMPLE 2
The results of electrolysis of zinc oxide under various conditions are shown below in Table ! TABLE 1
NOTES
SS = stainless steel
"Mech" refers to mechanical stirring only; "N2/mech" refers to refers to use of mechanical stirring in addition to nitrogen bubbling.
All solution based electrolysis used saturated solutions of zinc oxide in NaOH solution.
All slurry based electrolysis contained undissolved ZnO in the electrolyte during the entire electrolysis.
Zn particles deposited on the copper cathode were easily removable.
The precision of the corrosion results is about ±1g/45.5 kg Zn (the values expressed in g/45.5 kg Zn are normalized values).
The data in Table 1 clearly indicate that electrode corrosion is diminished when nitrogen or air is bubbled through the reactor during the electrochemical process (compared to the control process when only mechanical stirring is used). Furthermore, the use of mechanical stirring in conjunction with nitrogen or air bubbling does not adversely affect electrode corrosion
Each of the documents referred to above is incorporated he by reference in entirety, for all purposes. Except in the Examples, or where erwise explicitly indicated, all numerical quantities in this description specifying amounts and concentrations of materials, reaction and process conditions (such as temperature),

Claims

1. A low corrosion electrochemical process for preparing zinc metal which comprises electrochemically reducing an aqueous basic solution or slurry of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, wherein the electrochemical process is carried out in an undivided electrochemical cell, and wherein air or nitrogen is bubbled in through the solution or slurry of zinc oxide or said other zinc compound during said electrochemical process.
2. The electrochemical process of claim 1 that is a continuous process.
3. The electrochemical process of claim 1 that utilizes an electrochemical cell having a magnesium or copper cathode.
4. The electrochemical process of claim 1 that utilizes an electrochemical cell having a stainless steel or nickel anode.
5. The electrochemical process of claim 1 that utilizes an electrochemical cell having a stainless steel anode and a copper cathode.
6. The electrochemical process of claim 1 that utilizes an electrochemical cell having a nickel anode and a copper cathode.
7. The electrochemical process of claim 1 that is conducted at a temperature of from about 10°C to about 105°C.
8. The electrochemical process of claim 7, wherein the temperature ranges from about 40° to about 80°C.
9. The electrochemical process of claim 7, wherein the temperature ranges from about 60° to about 75°C.
10. The electrochemical process of claim 1 , wherein the aqueous base comprises ions of at least one alkali or alkaline earth metal and hydroxyl (OH") ions.
11. The electrochemical process of claim 10, wherein the alkali and alkaline earth metal ions are selected from sodium, potassium, and mixtures thereof and are provided in the form of a compound selected from hydroxides, and oxides.
12. The electrochemical process of claim 11 , wherein the compound is selected from the group consisting of sodium hydroxide and potassium hydroxide.
EP02785828A 2001-12-07 2002-12-05 Electrochemical process for preparation of zinc metal Withdrawn EP1458906A2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US15185 2001-12-07
US10/015,185 US20030106806A1 (en) 2001-12-07 2001-12-07 Electrochemical process for preparation of zinc metal
PCT/IB2002/005133 WO2003048425A2 (en) 2001-12-07 2002-12-05 Electrochemical process for preparation of zinc metal

Publications (1)

Publication Number Publication Date
EP1458906A2 true EP1458906A2 (en) 2004-09-22

Family

ID=21769971

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02785828A Withdrawn EP1458906A2 (en) 2001-12-07 2002-12-05 Electrochemical process for preparation of zinc metal

Country Status (4)

Country Link
US (1) US20030106806A1 (en)
EP (1) EP1458906A2 (en)
AU (1) AU2002351115A1 (en)
WO (1) WO2003048425A2 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2630469A1 (en) * 2005-11-22 2007-05-31 Paul R. Kruesi Methods of recovering and purifying secondary aluminum
US8409419B2 (en) * 2008-05-21 2013-04-02 Paul R. Kruesi Conversion of carbon to hydrocarbons

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE653557C (en) * 1936-08-16 1937-11-27 I G Farbenindustrie Akt Ges Production of zinc dust
DE4429195A1 (en) * 1994-08-18 1996-02-22 Dechema Electrolytic recovery of zinc@
DE4438692C2 (en) * 1994-10-29 2003-05-28 Outokumpu Oy Process for the electrochemical extraction of the metals copper, zinc, lead, nickel or cobalt
US20030183535A1 (en) * 2002-03-28 2003-10-02 Clariant International Ltd. Process for the preparation of zinc dithionite

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO03048425A2 *

Also Published As

Publication number Publication date
WO2003048425A3 (en) 2004-03-18
AU2002351115A1 (en) 2003-06-17
US20030106806A1 (en) 2003-06-12
WO2003048425A2 (en) 2003-06-12
AU2002351115A8 (en) 2003-06-17

Similar Documents

Publication Publication Date Title
US4555317A (en) Cathode for the electrolytic production of hydrogen and its use
US4324621A (en) Method and apparatus for controlling the quality of electrolytes
US20070125659A1 (en) Process for optimizing the process of copper electro-winning and electro-refining by superimposing a sinussoidal current over a continuous current
EP0043854B1 (en) Aqueous electrowinning of metals
CA2027656C (en) Galvanic dezincing of galvanized steel
US6569311B2 (en) Continuous electrochemical process for preparation of zinc powder
Kekesi Electrorefining in aqueous chloride media for recovering tin from waste materials
Dew et al. The effect of Fe (II) and Fe (III) on the efficiency of copper electrowinning from dilute acid Cu (II) sulphate solutions with the chemelec cell: Part I. Cathodic and anodic polarisation studies
US6569310B2 (en) Electrochemical process for preparation of zinc powder
US20030106806A1 (en) Electrochemical process for preparation of zinc metal
EP0096662B1 (en) Method for the electrolytic production of lead
US5833830A (en) Redox control in the electrodeposition of metals
US6103088A (en) Process for preparing bismuth compounds
EP1229150A1 (en) Electrochemical process for preparation of Zinc powder
EP0206554B1 (en) Electrolytic process for manufacturing pure potassium peroxydiphosphate
JP5561201B2 (en) Method for producing electric cobalt or electric nickel
WO2003083178A1 (en) Process for the preparation of zinc dithionite
JPS6133918B2 (en)
JP2982658B2 (en) Method of lowering metal concentration in electroplating solution
US5534131A (en) Process for heavy metals electrowinning
US20030057105A1 (en) Compositions containing aqueous basic saturated solutions of zinc oxide and processes for preparing said solutions and zinc metal
CA1270462A (en) Process for preparation of glyoxylic acid through electrochemical anodic oxidation of glyoxal
EP3795717A1 (en) Sulfuric acid solution production method, and electrolysis vessel which can be used in said production method
Nagirnyi et al. Electrolytic preparation of vanadium (V) oxide from oxovanadium (IV) sulfate solutions in the presence of sodium ions
Seitaro Studies on Electrolytic Refining of Zinc. VII: Effects of Manganese on Corrosion of Lead Anode

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SI SK TR

AX Request for extension of the european patent

Extension state: AL LT LV MK RO

18W Application withdrawn

Effective date: 20040827