WO2022241517A1 - Cellule électrolytique - Google Patents

Cellule électrolytique Download PDF

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Publication number
WO2022241517A1
WO2022241517A1 PCT/AU2022/050483 AU2022050483W WO2022241517A1 WO 2022241517 A1 WO2022241517 A1 WO 2022241517A1 AU 2022050483 W AU2022050483 W AU 2022050483W WO 2022241517 A1 WO2022241517 A1 WO 2022241517A1
Authority
WO
WIPO (PCT)
Prior art keywords
metal
catholyte
solution
cathodic compartment
vessel
Prior art date
Application number
PCT/AU2022/050483
Other languages
English (en)
Inventor
Marius WIECZOREK
Aleksander NIKOLOSKI
Original Assignee
Plastic Fabricators (WA) Pty Ltd t/a PFWA
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
Priority claimed from AU2021901489A external-priority patent/AU2021901489A0/en
Application filed by Plastic Fabricators (WA) Pty Ltd t/a PFWA filed Critical Plastic Fabricators (WA) Pty Ltd t/a PFWA
Publication of WO2022241517A1 publication Critical patent/WO2022241517A1/fr

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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
    • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
    • C25C1/06—Electrolytic production, recovery or refining of metals by electrolysis of solutions or iron group metals, refractory metals or manganese
    • C25C1/10—Electrolytic production, recovery or refining of metals by electrolysis of solutions or iron group metals, refractory metals or manganese of chromium or manganese
    • 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
    • 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
    • C25C7/04—Diaphragms; Spacing elements
    • 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
    • C25C7/06—Operating or servicing

Definitions

  • the present disclosure relates to an electrolytic cell, in particular an electrolytic cell for electrowinning a metal from a metal-bearing solution.
  • Electrowinning is an electrolytic process in which a current is passed between an anode and a cathode in an electrolytic cell containing a metal-bearing solution, whereby the metal is reduced and deposited at the cathode. In many electrolytic reactions, oxygen will also be generated at the anode.
  • the process has broad application in metal extraction and recovery because several metals including copper, lead, molybdenum, gold, silver, zinc, cobalt and manganese may be suitably extracted from a metal-bearing solution by electrowinning.
  • the electrolytic cell may be configured to have separate anode and cathode compartments which are separated by a diaphragm.
  • the diaphragm must be sufficiently impermeable to prevent diffusion of the anolyte into the cathode compartment of the cell, while at the same time minimising the electrical resistance of the diaphragm such that the electrolytic cell can be operated at an appropriate cell voltage (approx. 4.5 V-5.5 V) and not become overheated.
  • the cathode may be subject to dendritic growth of metal particularly on its edges due to increased current density, the formation of metal nodules, or the purity of deposited metal may vary. Additionally, the formation of nodules may affect the current efficiency of the electrolytic cell.
  • the generation of oxygen at the anode may be accompanied by production of a metal oxide sludge (“anode sludge”).
  • anode sludge metal oxide sludge
  • the present disclosure provides an electrolytic cell, in particular an electrolytic cell for electrowinning a metal from a metal-bearing solution.
  • an electrolytic cell for electrowinning a metal from a metal-bearing solution
  • the electrolytic cell comprising: a vessel comprising a cathodic compartment and an anodic compartment separated by a panel of diaphragm fabric; the cathodic compartment containing a catholyte comprising the metal-bearing solution and a cathode at least partially immersed therein, the anodic compartment containing an anolyte comprising a spent solution derived from electrolysis of the catholyte in the cathodic compartment and an anode at least partially immersed therein; wherein the vessel comprises:
  • said means to maintain the catholyte at a predetermined temperature comprises an outlet and an inlet of the cathodic compartment in fluid communication with a pump to recirculate the catholyte through an external heat exchanger.
  • the conduit may extend to a lower portion of the cathodic compartment.
  • the conduit may be a pipe element inserted into the cathodic compartment.
  • the pipe element may be provided with a bubbler head.
  • the cathode and anode are arranged in parallel alignment with one another.
  • the vessel is provided with an anolyte overflow outlet.
  • the vessel has a floor provided with a drain to collect anode sludge produced by the anode.
  • the floor may be inclined towards the drain.
  • the vessel may be provided with a flushing valve to discharge anode sludge from the vessel floor.
  • an assembly of electrolytic cells for electrowinning a metal from a metal-bearing solution comprising: a vessel configured to define an electrolysis zone for electrowinning the metal from the metal-bearing solution and a spent solution zone in fluid communication with the electrolysis zone to facilitate removal of spent solution derived from electrolysis of the metal-bearing solution from the vessel, an arrangement of a plurality of alternating cathodic compartments and anodic compartments disposed in the electrolysis zone, wherein adjacent cathodic and anodic compartments are separated by a panel of diaphragm fabric, each cathodic compartment containing a catholyte comprising the metal-bearing solution and a cathode at least partially immersed therein, each anodic compartment containing an anolyte comprising the spent solution and an anode at least partially immersed therein; wherein the vessel comprises: (i) an inlet to receive a feedstream of the metal-bearing solution into the electro
  • the vessel comprises a frame configured to support the arrangement of alternating cathodic compartments and anodic compartments in the electrolysis zone,
  • the frame may facilitate flow of spent solution from the anodic compartments in the electrolysis zone to the spent solution zone.
  • the spent solution zone has a floor provided with a drain to collect anode sludge produced by the anode.
  • the floor may be inclined towards the drain.
  • the spent solution zone may be provided with a flushing valve to discharge anode sludge from the floor thereof.
  • said means to maintain the metal-bearing solution at a predetermined temperature comprises a heat exchange coil configured to be immersed in the electrolysis zone of the vessel in heat exchange communication with the metal-bearing solution, wherein the heat exchange coil comprises an inlet and an outlet for recirculation of a heat exchange medium.
  • the conduit to sparge the metal-bearing solution may correspond to an internal perimeter of the electrolysis zone and be provided with a plurality of apertures along its length.
  • the outlet for egress of the spent solution is configured to maintain a lower level of anolyte than catholyte in the vessel.
  • said outlet may comprise a weir having an effective height that may be operably varied.
  • a system for electrowinning a metal from a metal bearing solution comprising: an assembly of electrolytic cells as defined above; a source of the metal-bearing solution in fluid communication with the input port of the electrolysis zone of the vessel; and, an electric current supply associated with the anodes and the cathodes whereby supply of electric current causes metal to be reduced and deposited on a surface of the cathodes and oxygen to be generated on the anodes.
  • a cathodic compartment for an electrowinning cell comprising a box having at least one panel of diaphragm fabric, the cathodic compartment containing a catholyte comprising a metal-bearing solution and a cathode at least partially immersed therein, wherein the cathodic compartment is capable of being suspended in the electrowinning cell; the box comprising:
  • the input port is provided with a Y-shaped element to receive a combined stream of the feedstream and the recirculated catholyte.
  • the at least one panel of diaphragm fabric may be configured to remove catholyte as an overflow into an anodic compartment of said cell and maintain a predetermined level of catholyte in the cathodic compartment.
  • the at least one panel of diaphragm fabric may be provided with an catholyte overflow outlet therein.
  • the catholyte overflow outlet may include a plurality of channels in a lower rim thereof.
  • a lower rim of the catholyte overflow outlet may be bevelled, in particular in a direction biased towards the anodic compartment.
  • Figure 1 is a schematic representation of one embodiment of an electrolytic cell for electrowinning a metal from a metal-bearing solution
  • Figure 2 is a schematic representation of one embodiment of a cathodic compartment for the electrolytic cell shown in Figure 1 ;
  • Figure 3 is schematic representation of an alternative embodiment of a cathodic compartment for the electrolytic cell shown in Figure 1 ;
  • Figures 4a and 4b are respective schematic representations of alternative embodiments of catholyte overflow outlets formed in the panel of diaphragm fabric of the cathodic compartments;
  • Figure 5 is a partial side view of one embodiment of an electrolytic cell assembly for electrowinning a metal from a metal-bearing solution
  • Figure 6 is a partial end view of the electrolytic cell assembly as shown in Figure 5;
  • Figure 7 is a cross-section along line B-B of Figure 6 showing an alternating arrangement of anodes and cathodes;
  • Figure 8 is a perspective view of the embodiment shown in Figure 7;
  • Figure 9 is a perspective view of one embodiment of a heat exchanger coil arranged, in use, to be associated with the electrolytic cell assembly shown in Figures 5-8;
  • Figure 10 is a perspective view of one embodiment of a frame to facilitate fluid communication between an electrolysis zone and a spent solution zone in the electrolytic cell assembly shown in Figures 5-8;
  • Figure 11 is another perspective view of the frame shown in Figure 10;
  • Figure 12 is a graphic representation of cell potential and cathodic current density measured over a 24 h period of operation of the electrolytic cell as described herein with reference to the Example;
  • Figure 13 is a graphic representation of pH of the catholyte and anolyte measured over a 24 h period of operation of the electrolytic cell as described herein with reference to the Example;
  • Figure 14 is a graphic representation of catholyte temperature measured over a 24 h period of operation of the electrolytic cell as described herein with reference to the Example. Description of Embodiments
  • the present disclosure relates to an electrolytic cell, in particular to an electrolytic cell for electrowinning metal from a metal-bearing solution.
  • the term “about” as used herein means within 5%, and more preferably within 1%, of a given value or range. For example, “about 3.7%” means from 3.5 to 3.9%, preferably from 3.66 to 3.74%.
  • “about” is associated with a range of values, e.g., “about X% to Y%”, the term “about” is intended to modify both the lower (X) and upper (Y) values of the recited range. For example, “about 20% to 40%” is equivalent to “about 20% to about 40%”.
  • Figures 1-3 show one embodiment of an electrolytic cell 10 suitable for electrowinning a metal from a metal-bearing solution.
  • the metal-bearing solution may comprise a plurality of different metal ions including impurities in varying concentrations.
  • the electrolysis conditions e.g. cell potential, applied current, pH, temperature
  • electrolysis refers to an electrochemical process in which an electric current is used to generate an otherwise non-spontaneous electrochemical reaction.
  • the electrolytic cell 10 includes a tank 12 having opposing side walls 14, front and rear walls 16 and floor 18.
  • the tank 12 may be fabricated from any suitable rigid material that is chemically inert under the operating conditions of the electrolytic cell 12. Suitable rigid materials include, but are not limited to, metals and alloys or polymeric materials.
  • the tank 12 defines an anodic compartment 20 containing an anolyte and at least one anode 22 arranged to be at least partially immersed in the anolyte.
  • anolyte refers to an aqueous salt solution capable of allowing an electric current to flow to a positively-charged anode.
  • the anolyte may comprise a metal-depleted metal-bearing solution (i.e. spent catholyte), catholyte overflow (see below), an electrolyte having a composition that is compatible with the catholyte or a mixture of two or more of the foregoing.
  • the anolyte may be the same composition as the catholyte.
  • the front and rear walls 16 of the tank 12 are configured to support the at least one anode 22 to extend in parallel alignment with the side walls 14 of the tank 12.
  • the front and rear walls 16 may be provided with respective brackets (not shown) to support the anode 22 in a desired orientation in the tank 12.
  • the brackets may be integral with the inner surface of the front and rear walls 16 of the tank 12.
  • the brackets may be grooves or protrusions on the inner surface of the front and rear walls 16 in which respective ends of the anode 22 are received or supported thereon, respectively.
  • the tank 12 is configured to maintain a predetermined level of anolyte in the tank 12.
  • a side wall 14 of the tank 12 includes an overflow pipe 24.
  • the overflow pipe 24 facilitates egress of the anolyte from the tank 12 to maintain the level of anolyte in the tank 12 to marginally below the overflow pipe 24. It will be appreciated that the position of the overflow pipe 24 in the side wall 14 of the tank 12 will be selected to maintain a predetermined level of anolyte in the tank 12.
  • the overflow pipe 24 is disposed in an upper portion 14a of the side wall 14 of the tank 12.
  • the floor 18 of the tank 12 may be tapered or inclined towards a drain 26 that is arranged, in use, to collect anode sludge generated at the anode 22 during electrolysis.
  • the term “anode sludge” as used herein refers to insoluble compounds, for example metal oxides, generated at the anode 22 during electrolysis which tend to sink under gravity to the floor 18 of the tank 12.
  • the tank 12 may be further provided with a flushing valve 28 proximal the drain 26 to facilitate removal of the anode sludge from the tank 12.
  • the flushing valve 28 may be operated on an intermittent basis, as desired, in particular when the amount of anode sludge is above acceptable levels in the tank 12.
  • the electrolytic cell 10 also includes at least one cathodic compartment 30 containing a catholyte and a cathode 32 adapted to be at least partially immersed in the catholyte.
  • a catholyte refers to an aqueous salt solution capable of allowing an electric current to flow from a negatively-charged cathode.
  • the catholyte comprises the metal-bearing solution resident in the cathodic compartment 30.
  • the catholyte may comprise a mixture of feedstream comprising the metal-bearing solution and metal-depleted metal-bearing solution from which the target metal has been progressively reduced and deposited on the cathode 32.
  • the cathodic compartment 30 is defined by a box 34 that is adapted to be suspended in the tank 12 and at least partially immersed in the anolyte.
  • the box 34 has opposing side walls 36, front and rear walls 38, base 40 and a top 42 having a cut-out portion 44 therein configured to receive and support the cathode 32.
  • the cut-out portion 44 may be configured in parallel alignment with the side walls 36 so that the cathode 32 extends between the front and rear walls 38 in parallel alignment with the side walls 36 of the box 34.
  • the box 34 is disposed in the tank 12 in an arrangement in which the cathode 32 and the anode 22 are in parallel alignment with one another.
  • front and rear walls 38 of the box 38 may be configured to be engaged with associated brackets on respective front and rear walls 16 of the tank 12 so that the side walls 36 of the cathodic compartment 30 are in parallel alignment with the side walls 14 of the tank 12.
  • the box 34 may be fabricated from any suitable rigid plastic material that is chemically inert under the operating conditions of the electrolytic cell 12.
  • suitable rigid plastic materials include, but are not limited to, polymeric materials such as polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, and so forth.
  • the box 34 is provided with at least one panel 46 of diaphragm fabric.
  • the diaphragm fabric is sufficiently permeable to facilitate fluid flow of catholyte from the cathodic compartment 30 to the anodic compartment 20 and flow of electric current between the anodic and cathodic compartments 20, 30 of the electrowinning cell 10.
  • the diaphragm fabric may be a woven or non-woven polymeric material. Suitable examples of woven or non-woven polymeric materials include, but are not limited to, polyester and polypropylene filter cloth, polyvinyl chloride, acrylonitrile.
  • the panel(s) 46 may be disposed in a correspondingly shaped cut-out portion 48 in one or both of the opposing side walls 36. In this way, the panel 46 may be in spaced parallel alignment with the cathode 32.
  • the panel 46 may be fixed to a margin surrounding the cut-out portion 48 by any suitable technique. For example, outer edges of the panel 46 may be fixed to the margin surrounding the cut-out portion 48 by a suitable adhesive, such as silicone or by plastic welding. Alternatively, the panel 46 may be clamped to the side wall 36 by interposing the panel 46 between the side wall 36 and a gasket (not shown) which is mounted thereon.
  • the panel 46 may be additionally rigidified by interposing the panel 46 between the side wall 36 and a mesh spacer (not shown) which is mounted thereon.
  • the panel 46 of diaphragm fabric may be configured to remove catholyte as an overflow into the anodic compartment 20.
  • the at least one panel 46 of diaphragm fabric may be provided with an catholyte overflow outlet 50 therein.
  • the catholyte overflow outlet 50 is configured as a slit in the diaphragm fabric.
  • the catholyte overflow outlet 50 may include a plurality of channels 52 in a lower rim 54 thereof.
  • the lower rim 54 of the catholyte overflow outlet 50 may be bevelled, in particular in a direction biased towards the anodic compartment 20.
  • the side wall 36 of the box 34 may include one or more catholyte overflow outlets 50’ to allow catholyte to egress to the anodic compartment 20.
  • the catholyte overflow outlets 50’ will be disposed above the panel 46 of diaphragm fabric. It will be appreciated that the catholyte overflow outlets 50’ in the side walls 36 of the box 34 may be slits, circular holes or other suitably-shaped apertures.
  • the catholyte overflow outlet 50 may be disposed in an upper portion of the panel 46 at an effective height sufficient to maintain a predetermined level of catholyte in the cathodic compartment 30.
  • the predetermined level of catholyte in the cathodic compartment 30 is selected to establish and maintain an effective hydrostatic head between the cathodic and anodic compartments 30, 20 to ensure catholyte flows from the cathodic compartment 30 to the anodic compartment 20.
  • the box 34 is provided with an input port 56 to receive a feedstream of the metal bearing solution into the cathodic compartment 30.
  • the input port 56 may be disposed in the top 42 proximal to the cut-out portion 44 so that feedstream is fed to an upper portion of the cathodic compartment 30.
  • the input port 56 may be disposed in the top 42 in fluid communication with a passageway (56’) extending downwardly through one of the front, rear or side walls 38, 36 and into a lower portion of the cathodic compartment 30.
  • the flow of feedstream into the cathodic compartment 30 may result in temperature and pH differentials between incoming feedstream and catholyte resident in the cathodic compartment 30, particularly if the incoming feedstream is not mixed with the catholyte. While not bound by theory, the inventors have opined that maintaining the catholyte at a constant temperature and pH within the cathodic compartment 30 during electrolysis improves homogeneous deposition of metal on the cathode 32.
  • the electrowinning cell 10 may be configured to recirculate the catholyte through a heat exchanger 100.
  • the top 42 of the box 34 may be provided with an outlet 58 and an inlet 60 in fluid communication with a pump 200 to recirculate the catholyte through the heat exchanger 100.
  • the pump 200 may be any suitable pump including, but not limited to, a peristaltic pump.
  • the catholyte in the cathodic compartment 30 may be maintained at a predetermined temperature, generally from about 35 °C to about 45 °C, in particular from about 38 °C to about 42 °C, or about 40 °C.
  • Recirculating the catholyte through the heat exchanger 100 also maintains the catholyte in the cathodic compartment 30 at a relatively constant pH, in particular a pH that favours target metal reduction at the cathode 32.
  • the input port 56 may be provided with a Y-shaped element 62 to receive a combined stream of the feedstream and the recirculated catholyte.
  • the electrowinning cell 10 may be configured to mix the feedstream and the catholyte in the cathodic compartment 30.
  • the box 34 may be provided with a conduit 64 to receive a gas stream to sparge the catholyte.
  • the conduit 64 may extend from a further inlet 66 in the box 34 to a lower portion of the cathodic compartment 30.
  • the conduit 34 may be a pipe element inserted into the cathodic compartment.
  • the pipe element may be provided with a bubbler head to improve gas distribution in the catholyte and therefore enhance mixing.
  • the gas stream may comprise air or an inert gas such as nitrogen or argon.
  • the anode 22 and the cathode 32 may be fabricated from an electrically conductive material that is inert or insoluble under the electrolysis conditions.
  • the anode 22 may be fabricated from an electrically conductive material having an acceptable oxygen overvoltage and minimum side reactions.
  • Suitable examples of electrically conductive materials from which the anode may be fabricated include, but are not limited to, lead, a lead alloy (e.g. Pb-Ag, 99:1 ) or a mixed metal oxide, such as a dimensionally stable anode.
  • Dimensionally stable anodes comprise a substrate, such as a titanium plate or mesh, with a plurality of metal oxides coated thereon.
  • the cathode 32 may be fabricated from an electrically conductive material having a high hydrogen overvoltage and surface properties that subsequently allow the deposited metal to be readily removed.
  • Suitable examples of electrically conductive materials from which the cathode 32 may be fabricated include, but are not limited to, metals such as titanium, copper, aluminium or alloys such as stainless steel, in particular 316 stainless steel, and Hastelloy.
  • the term THastelloy’ refers to a group of corrosion-resistant nickel alloys, namely the Ni-Mo and the Ni-Cr-Mo alloys.
  • Hastelloy electrodes are characterized by high resistance to hydrochloric, sulfuric, phosphoric, acetic and formic acids, media containing chloride and fluoride ions.
  • the cathode 32 may also be a composite of the aforementioned materials.
  • the cathode 32 may comprise a busbar fabricated from copper having a stainless steel outer layer. The stainless steel outer layer may be applied to the copper by wrapping and welding a stainless steel sheet thereto.
  • the anode 22 will have a smaller surface area than the cathode 32. In some embodiments, the anode 22 has a surface area less than half the surface area of the cathode 32.
  • a suitable power supply may be configured in electrical communication with the anode 22 and the cathode 32 to supply a cell potential of from about 4.0 V to about 5.0 V to the electrowinning cell 10 to maintain a current density of about 200 A/m 2 to about 600 A/m 2 , in particular a current density of about 240 A/m 2 to about 500 A/m 2 .
  • an assembly of electrolytic cells may be provided by arranging a plurality of anodes 22 and a plurality of cathodes 32 in spaced alternating parallel alignment with one another.
  • the anodes 22 and cathodes 32 may be as described above.
  • a vessel 110 configured to define an electrolysis zone 112 and a spent solution zone 114 in fluid communication with the electrolysis zone 112.
  • the electrolysis zone 112 houses an arrangement of alternating cathodic compartments 116 and anodic compartments 118.
  • Each cathodic compartment 116 contains the metal-bearing solution and a cathode 32 at least partially immersed therein and each anodic compartment 118 contains an anolyte (i.e. spent solution) and an anode 22 at least partially immersed therein.
  • each anodic compartment 118 is defined by a an open-ended bag 120 fabricated from four interconnecting panels of diaphragm fabric.
  • the diaphragm fabric may be a woven or non-woven polymeric material. Suitable examples of woven or non-woven polymeric materials include, but are not limited to, polyester and polypropylene filter cloth, polyvinyl chloride, acrylonitrile.
  • the bag 120 may be suspended from rigid rods 122 supported by a frame 124, as shown in Figure 11 , as will be described later.
  • the anodic compartments 118 are spaced in parallel alignment with one another in the electrolysis zone 112, whereby respective spaces therebetween define the cathodic compartments 116 in the electrolysis zone 112.
  • the vessel 110 may include opposing side walls 126, front and rear walls 128 and a floor 130.
  • the floor 130 of the vessel 110 may be supported by a pedestal 132 and a base 134.
  • the front and rear walls 128 may each be provided with a laterally extending flange 136 that may be conveniently used as lifting points for the vessel 110 and its contents.
  • the vessel 110 may be fabricated from any suitable rigid material that is chemically inert to the metal-bearing solution, the resulting spent solution and the operating conditions of the electrolysis. Suitable rigid materials include, but are not limited to, metals and alloys or polymeric materials, such as polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, and so forth.
  • the electrolysis zone 112 of the vessel is arranged to facilitate recovery of metal from the metal-bearing solution by means of electrolysis, in particular by electroplating the metal on the cathodes 32 in the cathodic compartments 116.
  • the electrolysis zone 112 may take the form of an inner chamber 138 generally spaced apart from and disposed above the floor 130 of the vessel 110.
  • the inner chamber 138 is defined by an inner wall 140 extending between the front and rear walls 128 and spaced apart from one of the side walls 126a in parallel alignment therewith.
  • a lower end 142 of the inner wall 140 is spaced apart from and disposed above the floor 130 of the vessel 110.
  • the lower end 142 is provided with a first lip 144 laterally extending therefrom.
  • a second lip 146 laterally extends from the other of the side walls 126b spaced apart from and above the floor 130 of the vessel 110 so that the first and second lips 144, 146 are in lateral facing alignment with one another.
  • the electrolysis zone 112 is provided with an inlet 148 to deliver metal-bearing solution thereto.
  • the inlet 148 is disposed in a box-like projection 150 disposed in the side wall 126b in fluid communication with the inner chamber 138.
  • the metal-bearing solution flows into the electrolysis zone 112 and the cathodic compartments 116.
  • the anodic compartments 118 may also contain the metal-bearing solution.
  • spent solution seeps from the cathodic compartments 116 into the anodic compartments 118 and thence to the spent solution zone 114 as will be described later.
  • the flow of metal-bearing solution into the electrolysis zone 112 may result in temperature and pH differentials between incoming feedstream and catholyte resident in the cathodic compartment 116, particularly if the incoming feedstream is not mixed with the catholyte. While not bound by theory, the inventors have opined that maintaining the catholyte at a constant temperature and pH within the cathodic compartment 116 during electrolysis improves homogeneous deposition of metal on the cathode 32.
  • the vessel 110 is provided with a heat exchange coil 152 configured to be immersed in the electrolysis zone 112 of the vessel 110 in heat exchange communication with the metal-bearing solution.
  • the heat exchange coil 152 includes an inlet 154a and an outlet 154b for recirculation of a heat exchange medium. Any suitable heat exchange medium, such as water or glycol may be circulated through the heat exchange coil 152.
  • the heat exchange coil 152 may conform to an internal perimeter of the inner chamber 138 of the vessel 110, wherein a base thereof may be supported by the first and second lips 144, 146.
  • the vessel 110 also includes a conduit 156 configured to be immersed in the electrolysis zone 112 of the vessel 110 to sparge the metal-bearing solution and enhance mixing.
  • a conduit 156 is perforated along its length.
  • the gas stream may comprise air or an inert gas such as nitrogen or argon.
  • the frame 124 is configured to support the arrangement of alternating cathodic compartments 116 and anodic compartmentsl 18 in the electrolysis zone 112, Referring to Figures 10 and 11 , the frame 124 may include an open upper rectangular section 158 interconnected to a generally closed lower rectangular section 160 by a plurality of generally vertical elongate members 162. In use, the lower rectangular section 160 of the frame 124 is supported by the first and second lips 144, 146 in the electrolysis zone 112. In this way, the frame 124 may be readily inserted into the vessel 110 or removed therefrom.
  • Respective front and rear sides 164 of the upper rectangular section 158 are provided with correspondingly aligned grooves 166.
  • the grooves 166 are arranged, in use, to support the rigid rods 122 from which the open-ended bags 120 of diaphragm fabric are suspended.
  • the bags 120 may be additionally supported on the lower rectangular section 160 by means of ties or weights.
  • the lower rectangular section 160 is provided with a plurality of openings 168 which are configured to align with respective overlying anodic compartments 118 so that the respective lower openings of the open-ended bags 120 align with the openings 168.
  • the electrolysis zone 112 is in fluid communication with the spent solution zone 114, and spent solution may flow from the anodic compartments 118 in the electrolysis zone 112 to the spent solution zone 114.
  • the lower rectangular section 160 of the frame 124 may be provided with a rebate to conveniently house the conduit 156 to sparge the electrolysis zone 112.
  • the frame 124 may be fabricated from any suitable rigid plastic material that is chemically inert under the operating conditions of the assembly of electrolytic cells 100.
  • suitable rigid plastic materials include, but are not limited to, polymeric materials such as polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, and so forth.
  • the anodes 22 and cathodes 32 may be lowered into and immersed in the respective anodic and cathodic compartments 118, 116.
  • respective upper edges 170 of the front and rear walls 128 of the vessel 110 are provided with regularly spaced and correspondingly aligned grooves or protrusions 172 to support the anodes and cathodes 22, 32 in spaced alternating parallel alignment.
  • the anodes and the cathodes 22, 32 may be respectively electrically connected to an electric current supply source via an intercell busbar. Banana plugs or similar may be used to allow the cathodes 32 to be readily removed without having to risk significant dissolution of metal on the cathodes 32 at termination of the electrolysis.
  • a suitable power supply may be configured in electrical communication with the anodes 22 and the cathodes 32 to supply a cell potential of from about 4.0 V to about 5.0 V to the assembly 100 of electrolytic cells to maintain a current density of about 200 A/m 2 to about 600 A/m 2 , in particular a current density of about 240 A/m 2 to about 500 A/m 2 .
  • the floor 130 of the vessel 110 may be tapered or inclined towards a drain 174 that is arranged, in use, to collect anode sludge generated at the anodes 22 during electrolysis.
  • the vessel 110 may be further provided with a flushing valve 176 proximal the drain 174 to facilitate removal of the anode sludge from the spent solution zone 114 of the vessel 110.
  • the flushing valve 176 may be operated on an intermittent basis, as desired, in particular when the amount of anode sludge is above acceptable levels in the vessel 110.
  • the spent solution zone 114 of the vessel 110 is generally L-shaped and includes the spaces defined between the floor of the vessel 130, the first and second lips 144, 146 and the lower rectangular section 160 of the frame 124, and between the side wall 126a and the inner wall 140.
  • the spent solution zone 114 of the vessel 110 is configured to maintain a predetermined level of spent solution in the vessel 110.
  • the effective level of spent solution in the spent solution zone 114 should be lower than the effective level of metal-bearing solution in the electrolysis zone 112.
  • the level of metal-bearing solution in the cathodic compartments 116 should be less than the level of solution in the anodic compartments 118.
  • the spent solution zone 114 is provided with an outlet 178 for egress of the spent solution therefrom.
  • the outlet 178 is disposed in a box-like projection 180 disposed in an upper section of the side wall 126a.
  • the box-like projection 180 is in fluid communication with the spent solution zone 114.
  • the outlet 178 is an upright pipe with a threaded fitting whose effective height in the box-like projection 180 can be manually adjusted to vary the level of liquid, thus behaving effectively as a weir. In use, the effective height of the outlet 178 is adjusted so that the level of spent solution in the vessel 110, and in particular in the anodic compartments 118, is less than the level of metal-bearing solution in the cathodic compartments 116.
  • the electrowinning cell 10 as described with reference to Figures 1 to 4b was used to recover manganese (Mn) from a manganese-containing feed solution with a composition according to Table 1 and operated under conditions summarised in Table 2.
  • the cell 10 was also provided with sensors to measure pH, temperature and cell potential. The electrolysis was performed for 4 , 8 and 24 h, respectively.
  • Fresh feed was fed into the cathodic compartment 30 through input port 56.
  • the amount of fresh feed introduced into the cell 10 was weighed on a scale and automatically logged.
  • the catholyte in the cathodic compartment 30 was circulated through a heat exchanger 100 via a peristaltic pump 200 to maintain the desired cell temperature of 40 °C.
  • the catholyte flowed from the cathodic compartment 30 through the panel 46 of diaphragm fabric into the anodic compartment 20 and also exited the cathodic compartment 30 through catholyte overflow outlet 50 in the panel 46 of diaphragm fabric.
  • Figure 12 shows the recorded cell potential and cathodic current density over a 24 h period. An average cell potential of 4.7 V was obtained in the absence of drift across the 24 h test period. The cell 10 was consistently operated at about 32 A/m 2 throughout the 24 h test period. The liquid level in the anodic and cathodic compartments 20, 30 was steadily maintained throughout the test with a fixed difference in liquid levels between the two compartments.
  • Figure 13 shows respective pH measurements of the catholyte in the cathodic compartment 30 and the anolyte in the anodic compartment 20 of the cell 10 during the 24 h test.
  • the gradual increase in catholyte pH from 7.2 to 7.9 and decrease in the anolyte pH with operating time is consistent with expected behaviour.
  • Figure 14 shows the catholyte temperature recorded during the 24 h test.
  • the small variation in temperature demonstrates that gas sparging in the cathodic compartment 30 ensure good mixing of recirculated catholyte and feed in the cathodic compartment 30.
  • the anode 20 showed evidence of a dark black coating of MnC>2. There was a slight difficulty in draining the anode sludge from the cell 10 because flakes of MnC>2 had peeled off from the anode 20, but this did not present a major problem.
  • the surface of the panel of diaphragm fabric proximal the anode 20 also had dark staining but, on inspection after the tests, showed no damage or tears and its permeability was remained uncompromised.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)

Abstract

La divulgation concerne un ensemble de cellules électrolytiques destinées à l'extraction par voie électrolytique d'un métal à partir d'une solution contenant du métal. L'ensemble comprend un récipient ayant une zone d'électrolyse et une zone de solution usée en communication fluidique avec la zone d'électrolyse, ainsi qu'un agencement de compartiments cathodiques et de compartiments anodiques alternés disposés dans la zone d'électrolyse. Les compartiments cathodiques et anodiques adjacents sont séparés par un panneau de tissu de membrane. Le récipient comprend en outre : (i) une entrée destinée à recevoir un courant d'alimentation en solution contenant du métal dans la zone d'électrolyse, (ii) un moyen pour maintenir la solution contenant du métal dans la zone d'électrolyse à une température prédéterminée, (iii) un conduit destiné à recevoir un flux de gaz pour disperser la solution contenant du métal ; et (iv) une sortie dans la zone de solution usée destinée faire sortir la solution usée.
PCT/AU2022/050483 2021-05-19 2022-05-19 Cellule électrolytique WO2022241517A1 (fr)

Applications Claiming Priority (2)

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AU2021901489A AU2021901489A0 (en) 2021-05-19 Electrolytic Cell
AU2021901489 2021-05-19

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2361143A (en) * 1940-12-28 1944-10-24 Electro Manganese Corp Manganese deposition control
WO2002066709A1 (fr) * 2001-02-23 2002-08-29 Norsk Hydro Asa Procédé et cellule d'extraction électrolytique pour la production de métal
JP2009167453A (ja) * 2008-01-15 2009-07-30 Sumitomo Metal Mining Co Ltd 酸性塩化物水溶液からの鉄の電解採取方法
WO2014161928A1 (fr) * 2013-04-04 2014-10-09 Industrie De Nora S.P.A. Cellule électrolytique pour électro-obtention de métal

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2361143A (en) * 1940-12-28 1944-10-24 Electro Manganese Corp Manganese deposition control
WO2002066709A1 (fr) * 2001-02-23 2002-08-29 Norsk Hydro Asa Procédé et cellule d'extraction électrolytique pour la production de métal
JP2009167453A (ja) * 2008-01-15 2009-07-30 Sumitomo Metal Mining Co Ltd 酸性塩化物水溶液からの鉄の電解採取方法
WO2014161928A1 (fr) * 2013-04-04 2014-10-09 Industrie De Nora S.P.A. Cellule électrolytique pour électro-obtention de métal

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