Cartridge electrode configurations

Abstract

Aspects disclosed herein include cartridge electrodes for use in electrochemical systems, a cartridge electrode comprising: a plurality of elongated electrode elements, each elongated electrode element comprising: a conductive structure; a tubular separator; a reaction space between the conductive structure and the separator; and a reaction surface within the reaction space; an in-flow manifold configured to direct a cartridge electrolyte through the reaction space of each of the elongated electrode elements; and an out-flow manifold configured to receive the cartridge electrolyte exiting each of the reaction spaces of the elongated electrode elements.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 63 / 757,142, filed Feb. 11, 2025, which is incorporated herein by reference in its entirety for all purposes.BACKGROUND

[0002] Electrochemical methods for extracting and / or purifying metals from one or more feedstock materials may be commonly referred to as “electrowinning” or “electro-refining.” For example, metals such as zinc and copper are commonly extracted from feedstocks by acid leaching, and the metals are “electroplated” onto cathodes while hydrolyzing water to produce oxygen at anodes of such electrowinning systems. In many zinc and copper electrowinning systems, a single electrolyte contacts both the anode and the cathode. This is possible because, in aqueous solutions, zinc and copper only have a single stable oxidation state (Cu2+ and Zn2+).

[0003] However, compared with zinc and copper, electrowinning of iron is more challenging, in part due to the fact that aqueous iron is stable in both Fe2+ (ferrous) and Fe3+ (ferric) ionic states. An electrochemical cell with a common (unseparated) electrolyte in contact with both anode and cathode will tend to experience a “shuttling” of ions in which ferrous ions are oxidized to ferric at the anode while ferric ions are reduced to ferrous at the cathode. The ferrous / ferric shuttle represents wasted energy as ions simply shuttle back and forth between the two aqueous oxidation states without achieving the desired reaction (e.g., electroplating metallic iron).

[0004] One way of mitigating the ferrous / ferric shuttle is to physically separate the anode-contacting electrolyte (“anolyte”) from the cathode-contacting electrolyte (“catholyte”) such that physical mixing of the electrolytes is prevented. However, provision may still be made for one or more ionic charge-carriers to pass through such a separation, such as via a salt-bridge, a semi-permeable membrane, an ion-exchange membrane, or other ion-conductive material or structure.

[0005] When the ionic conductive separator is a polymeric membrane (e.g., a porous membrane or an ion-selective membrane), it is desirable for the membrane to be consistently held at a desired physical distance from a reactive surface of the anode and / or cathode electrode. Variations in the distance between the separator and the electrode surface (e.g., across the membrane area or over time) can cause electrochemical inefficiencies which can impact the performance of the electrochemical system overall. Unfortunately, many separator membrane materials are quite flexible and prone to being displaced by differences in fluid pressures across the membrane, thereby causing inefficiencies or other problems with the performance of the electrochemical system.

[0006] Described herein are various devices, methods, systems, configurations, and / or processes for addressing the above-described challenges or other challenges as described or apparent to those skilled in the art of electrochemical systems.SUMMARY

[0007] In various aspects, the present disclosure provides processes, systems, methods, devices, and apparatus for configuring electrochemical electrode cartridges for effective separation of electrolytes while allowing for removal of electrode cartridges from an electrochemical cell for cell maintenance, repair or replacement of electrodes, or other operations.

[0008] Aspects disclosed herein include cartridge electrodes for use in electrochemical systems, a cartridge electrode comprising: a plurality of elongated electrode elements, each elongated electrode element comprising: a conductive structure; a tubular separator; a reaction space between the conductive structure and the separator; and a reaction surface within the reaction space; an in-flow manifold configured to direct a cartridge electrolyte through the reaction space of each of the elongated electrode elements; and an out-flow manifold configured to receive the cartridge electrolyte exiting each of the reaction spaces of the elongated electrode elements.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a schematic illustration of a prior art electrowinning bath comprising positively charged anodes and negatively charged cathodes.

[0010] FIG. 2 is a schematic illustration of an electrowinning bath with electrodes shown removed from the bath.

[0011] FIG. 3A is a schematic diagram showing a cross-sectional view of an example cartridge electrode.

[0012] FIG. 3B is a schematic diagram showing cross-sectional view of an example cartridge electrode showing deflection of a separator membrane.

[0013] FIG. 4 is a schematic diagram showing an electrochemical cell with a separator membrane held against an electrode by a difference in electrolyte pressure on opposite sides of the separator.

[0014] FIG. 5 is a schematic diagram showing an electrochemical system in which one electrolyte flows under the power of a suction pump.

[0015] FIG. 6 is a schematic diagram showing an electrochemical cell in which one electrolyte is maintained at a higher hydrostatic head (liquid surface level) than another electrolyte.

[0016] FIG. 7 is a schematic diagram showing a cartridge electrode comprising an array of elongated electrode elements.

[0017] FIG. 8 is a schematic perspective view diagram showing a cartridge electrode comprising an array of elongated electrode elements and a cover sheet.

[0018] FIG. 9 is a schematic diagram showing a cross section of a portion of an elongated electrode element (such as through line B-B of FIG. 7).

[0019] FIG. 10 is a schematic diagram showing a transverse cross section of an example flow diffusion coupling.

[0020] FIG. 11 is a schematic diagram showing a cartridge electrode comprising an array of elongated electrode elements and a pair of counter-electrodes positioned over an electrolyte bath.STATEMENTS REGARDING CHEMICAL COMPOUNDS AND NOMENCLATURE

[0021] In general, the terms and phrases used herein have their art-recognized meaning, which can be found by reference to standard texts, journal references and contexts known to those skilled in the art. The following definitions are provided to clarify their specific use in the context of this disclosure.

[0022] As used herein, the term “ionic conductivity” is used as conventionally understood in the field of electrochemistry and refers to a material property of permitting or encouraging transport of one or more ionic species through a material or component, the material or component being solid, fluid, or a combination thereof.

[0023] As used herein, the term “electronic conductivity” is used synonymously with “electric conductivity” and “electrical conductivity” (including all equivalent adverb forms) and refers to a material property of conducting electrons through a material or component, the material or component being solid, fluid, or a combination thereof.

[0024] As used herein, the term “reaction surface” (such as but not limited to reaction surface 306 or 904) refers to a material or component that facilitates one or more electrochemical reactions (such as but not limited to ion oxidation or ion reduction) on at least a portion of its surface, the reaction surface being at least partially provided between a conductive structure (such as but not limited to conductive structure 304 or 902) and a separator (such as but not limited to separator 308, 406, or 908). In various aspects, the reaction surface is at least partially in physical contact with the conductive structure and at least partially in physical contact with the separator. As an illustrative example, corresponding to some aspects described elsewhere herein, a reaction surface (such as but not limited to reaction surface 306) may be a cylindrical carbon felt or foam, which optionally has a concentric hollow middle portion containing a concentric cylindrical conductive structure (e.g., a metal rod or stem), with a separator (e.g., a film or sheet of an ion exchange material) surrounding (e.g., wrapped around) at least a portion of the reaction surface, where in some aspects the reaction surface is at least partially in physical contact with the conductive structure and concurrently at least partially in contact with the separator.

[0025] As used herein, the term “separator” is used as conventionally understood in the field of electrochemistry and refers to a structure for separating two or more electrochemical reactants (e.g., solid, liquid, and / or gaseous reactants) within an electrochemical cell. Separators generally take the form of a material layer configured to regulate, mitigate, or restrict transport of some chemical species from one region to another. In an electrochemical cell containing solid or fluid reactants, a separator generally separates two regions or volumes, such as one electrolyte (e.g., catholyte, midlyte, or anolyte) from another electrolyte (e.g., catholyte, midlyte, or anolyte), thereby regulating, mitigating, or restricting transport of molecules and / or ions from one electrolyte to the other. Separators may include electrically non-conductive (often polymeric) materials that are porous (including microporous and nanoporous).

[0026] Separators are often (though not necessarily) extruded or cast polymer sheets with a defined or specified range of porosity. Microporous and nanoporous separators generally have a very low water permeability while allowing some bi-directional transport of ionic species. In some cases, the term “membrane” may be synonymous with “separator,” unless either term is further specified (e.g., “ion exchange membrane”).

[0027] Separators may comprise polymers and / or ceramic materials, including porous materials, microporous materials, nanoporous materials, and ion exchange materials, among other possible material constituents. As used herein, the term “tubular separator” refers to a separator, as just described, at least partially having a tubular or cylindrical shape, form, or configuration. For example, a separator may be formed into a tubular separator by providing a sheet or film of a separator material wound or wrapped around a cylindrical structure.

[0028] As used herein, the terms “ion-selective membrane” and “ion exchange membrane” are used as conventionally understood in the field of electrochemistry and refer to a non-porous, semi-permeable membrane that selectively permits the transport of specific ions while substantially excluding others, based on their charge, size, or both. lon-exchange membranes may be polymer and / or ceramic materials. Ion exchange membranes may comprise fixed ionic groups-either cationic or anionic-that facilitate the movement of counter-ions (ions of opposite charge) through the membrane matrix, while repelling co-ions (ions of like charge). Ion exchange membranes may be classified as cation exchange membranes (CEMs), which allow the passage of cations, or anion exchange membranes (AEMs), which allow the passage of anions. The non-porous nature of the membrane ensures that ion transport occurs via diffusion through the polymer matrix rather than through physical pores.

[0029] As used herein, the term “ion exchange resin” refers to a bulk material (regardless of physical form-factor) with properties of conducting one or more ionic species while preventing or restricting conductivity of one or more other ionic species.

[0030] As used herein, the term “cation exchange membrane” is used as conventionally understood in the field of electrochemistry and refers to an ion-selective membrane that permits or encourages transport (ionic conductivity) of cations (positively charged ions) while restricting or preventing transport of anions (negatively charged ions).

[0031] As used herein, the term “proton exchange membrane” is used as conventionally understood in the field of electrochemistry and refers to an ion-selective membrane that permits or encourages transport of protons (and optionally other cations) while restricting or preventing conductivity of anions.

[0032] As used herein, the term “anion exchange membrane” is used as conventionally understood in the field of electrochemistry and refers to an ion-selective membrane that permits or encourages transport of negatively charged anions while restricting or preventing conductivity of protons and other cations.

[0033] As used herein, the term “electrolyte” refers to a liquid (including aqueous liquids, ionic liquids, and other non-aqueous liquids) containing free ions capable of diffusing through the liquid. In some cases, electrolytes may comprise gaseous components, including dissolved gasses, gas bubbles in liquid, and gas / liquid mixtures.

[0034] As used herein, the term “catholyte” is used as conventionally understood in the field of electrochemistry and refers to an electrolyte in contact with an electrochemical cathode.

[0035] As used herein, the term “anolyte” is used as conventionally understood in the field of electrochemistry and refers to an electrolyte in contact with an electrochemical anode.

[0036] As used herein, the term “active area” is used as conventionally understood in the field of electrochemistry and refers to an area of an electrochemical cell in which electrochemical reactions occur. The “active area” of an electrochemical cell may correspond to an area of an anode, an area of a cathode, an area of a separator, or combinations of these. An “active area” of an electrode (anode or cathode) may be less than a total area of the electrode if portions of the electrode are blocked by ionically non-conductive materials that prevent ions or other electrochemical reactants from reaching those portions of the electrode surface.

[0037] As used herein, the terms “anode chamber” and “cathode chamber” are used as conventionally understood in the field of electrochemistry and refer to regions of an electrochemical cell containing “anolytes” and “catholytes,” respectively. Anode and / or cathode “chambers” may be fluidically sealed from other regions of a cell, and may be configured to allow electrolyte to flow-through the chamber or to statically contain the electrolyte (or both, potentially at different times). Other terms such as “volume,”“reaction space,” or “compartment” may be used in place of the word “chamber.” As used herein, the terms “metal rich solution,”“metal rich electrolyte”“leachate,”“lixiviant” or other related terms may refer to a liquid suitable for use as a catholyte in a metal electrowinning cell.

[0038] As used herein, the term “electrical source” may refer to any source of electrical energy, including electrical generation equipment such as turbines (whether powered by steam, wind, water or otherwise), photovoltaic cells, electrical grids, batteries, power supplies, rectifiers, inverters, or any other source of electrical energy, or any combination of sources, including conversion equipment.

[0039] As used herein, the term “electrical load” refers to a device or combination of devices capable of receiving and consuming, storing, or transporting electrical energy.

[0040] The term “pore”, as used herein, refers to small and / or tortuous openings or paths extending from one face of a planar material to the opposite face of the material.

[0041] The term “porous”, as used herein, refers to a material or structure within which pores are present, organized and / or arranged in the material. Thus, for instance, in a porous material, the pores are volumes within the body of the material where there is no material (e.g. voids). Pores in a material are not intended to include the space occupied by atoms, ions and / or molecules of a material including monomers, oligomers and polymers, for example, of a barrier or separator. Porous materials and pores may be characterized by certain pore characteristics including, but not limited to, an average pore size, a maximum pore size, an O90 pore size, pore tortuosity, and others. A pore size generally refers to a cross sectional dimension such as diameter or cross-sectional width. Generally, as used herein, an average pore size refers to an empirically-derived numerical average of the diameter (or corresponding cross-sectional dimension) of each pore of the plurality of pores of a material or item.

[0042] The term porosity refers to a quantitative characteristic of a porous material or structure. In some embodiments, porosity is a measure of the void (i.e. “empty”) volume, such as pores, in a material. Porosity may be expressed as the fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. As used herein, a porous material has characteristics allowing transport of protons across it via the Grotthuss mechanism.

[0043] As used herein, a “microporous” material is characterized by an average pore size and / or an O90 pore size selected from the range of greater than 100 nm to less than or equal to 1 μm. As used herein, a “nanoporous” material is characterized by an average pore size and / or an O90 pore size selected from the range of 0.1 nm to less than 100 nm.

[0044] As used herein, “permeability” of aqueous dissolved ions refers to the capacity of a material, such as a porous material, to permit the passage of dissolved ionic species, in an aqueous solution, through its structure. lon permeability encompasses the transport of ions driven by concentration gradients, electrochemical potential, pressure differentials, or other forces. In the context of porous materials, ion transport may occur through interconnected pores, channels, or voids within the material, and may be influenced by factors such as pore size distribution, surface charge, tortuosity, and the physicochemical interactions between the ions and the pore surfaces. lon permeability is typically, but not necessarily, quantified by measuring the flux of specific ions across the material under defined conditions and may be expressed in units such as moles per square meter per second (mol / m2·s).

[0045] The term “iron electroplating” (or “iron plating” as used synonymously herein) refers to a process by which dissolved iron is electrochemically reduced to metallic iron on a cathodic surface. Equivalent terms “electrodeposition,”“electroforming,” and “electrowinning” are also used herein synonymously with “iron electroplating.” The shape or form-factor of the electroplated iron need not be a “plate” by any definition of that term. For example, electroplated iron may take any shape or form and may be deposited on any suitable cathodic surface as described in various embodiments herein. Examples of possible physical forms of “electroplated” iron include chips, flakes, coins, crowns, powder, strips, or other shapes. In some embodiments, a cathodic surface material may be selected for a degree to which deposited iron adheres to the cathodic surface. For example, if a desired electroplated product is a powder, a cathodic surface with a low iron adhesion may be desired. Examples of materials with high and low iron adhesion properties are described herein, and additional examples will be clear to those skilled in the art. In various embodiments, some regions of a cathode may be masked prior to electroplating for producing electroplated material in a desired shape or form-factor, for example as described in U.S. Pat. No. 4,139,430, which is incorporated herein by reference to the extent not inconsistent herewith.

[0046] As used herein, electrochemically generated ions, such as electrochemically generated protons and electrochemically generated iron ions (e.g., Fe2+, Fe3+), refer to ions that are generated or produced in an electrochemical reaction. For example, electrochemical oxidation of water at an anode may electrochemically generate protons and electrochemically generate oxygen. For example, aqueous ferrous (Fe2+) ions in an anolyte may be electrochemically oxidized an anode to aqueous ferric (Fe3+) ions. As used herein, the term “anodically generated” ions refers to ions generated by electrochemically oxidation at an anode. As used herein, the term “anodically generated” ions refers to ions generated by electrochemically reduction at a cathode.

[0047] As used herein, aqueous protons and electrochemically generated protons are intended to be inclusive of aqueous protons and aqueous hydronium ions.

[0048] The term “dissolved” in reference to ions, such as dissolved ferric ions or dissolved ferrous ions, refers to ions dissolved and thereby solvated by a solvent such as water or an aqueous solution. As used herein, the term “aqueous ions”, such as aqueous ferric ions or aqueous ferrous ions, refers to ions dissolved in water. The term “non-dissolved” refers to a solid undissolved non-solvated species. The term “non-dissolved ferric” and “solid ferric” refer to any one or more solid compositions or materials in which ferric (Fe3+ or Fe(III)) exists in a non-dissolved solid, such as, for example, ferric in solid particles or pieces of hematite. As an illustrative example, reduction of solid hematite to solid magnetite comprises the reduction of non-dissolved (solid) ferric to non-dissolved (solid) ferrous. The term “non-dissolved ferrous” and “solid ferrous” refer to any one or more solid compositions or materials in which ferrous (Fe2+ or Fe(II)) exists in a non-dissolved solid, such as, for example, ferrous in solid particles or pieces of magnetite or wüstite. Likewise, the term “solid ions”, such as “solid iron ions”, refers to ions bound in a solid and undissolved composition.

[0049] As used herein, the term “material” is inclusive of pure materials and mixtures of a plurality of different materials or species.

[0050] As used herein, the term “wt. %” or “wt %” refers to a weight percent, or a mass fraction represented as a percentage by mass. The term “at. %” or “at %” refers to an atomic percent, or an atomic ratio represented as a percentage of a type of atom with respect to total atoms in a given matter, such as a molecule, compound, material, nanoparticle, polymer, dispersion, etc. The term “mol. %” refers to molar percent or percent by moles. The term “vol. %” refers to volume percent.

[0051] The term “predominantly” is used herein to refer to a property, condition, or value being greater than 50%. In specific instances, the term “predominantly” may indicate a property, condition, or value being greater than 60%, greater than 70%, greater than 80%, greater than 90%, greater than 95%, greater than 98%, greater than 99%, greater than 99.5%. For example, a material mixture characterized as “predominantly wüstite” is more than 50 mol. % wüstite, or in other instances at least 60 mol. % wüstite, at least 70 mol. % wüstite, at least 80 mol. % wüstite, at least 90 mol. % wüstite, at least 95 mol. % wüstite, at least 98 mol. % wüstite, at least 99 mol. % wüstite, at least 99.5 mol. % wüstite, with the balance being other compositions, such as but not limited to hematite, magnetite, iron metal, and / or impurities.

[0052] The terms “substantially” and “approximately” are used interchangeably and refer to a property, condition, or value that is equivalent to or is within a reasonable variance from a stated property, condition, or value. For example, a property, condition, or value described as “substantially” or “approximately” X (X being a number for purpose of this paragraph), may include properties, conditions, or values that are within 20%, within 10%, within 5%, within 1%, or within 0.1% of said X. Examples of such uses include phrases such as “substantially equal”, “substantially equivalent”, “substantially unchanged”, “approximately”, and “approximately equal to.”

[0053] As used herein, the term “and / or” is used herein, in the description and in the claims, to refer to a single element alone or any combination of elements from the list in which the term and / or appears. In other words, a listing of two or more elements having the term “and / or” is intended to cover embodiments having any of the individual elements alone or having any combination of the listed elements. For example, the phrase “element A and / or element B” is intended to cover embodiments having element A alone, having element B alone, or having both elements A and B taken together. For example, the phrase “element A, element B, and / or element C” is intended to cover embodiments having element A alone, having element B alone, having element C alone, having elements A and B taken together, having elements A and C taken together, having elements B and C taken together, or having elements A, B, and C taken together.

[0054] As used herein, the term “+” refers to an inclusive range of values, such that “X+Y,” wherein each of X and Y is independently a number, refers to an inclusive range of values selected from the range of X−Y to X+Y. In the cases of “X+Y” wherein Y is a percentage (e.g., 1.0±20%), the inclusive range of values is selected from the range of X−Z to X+Z, wherein Z is equal to X·(Y / 100). For example, 1.0±20% refers to the inclusive range of values selected from the range of 0.8 to 1.2.DETAILED DESCRIPTION

[0055] In the following description, numerous specific details of devices, device components and methods are set forth to provide a thorough explanation of the precise nature of the various inventions described herein. It will be apparent, however, to those of skill in the art that the various inventions can be practiced without these specific details. Without wishing to be bound by any particular theory, there may be discussion herein of beliefs or understandings of underlying principles relating to the devices and methods disclosed herein. It is recognized that regardless of the ultimate correctness of any mechanistic explanation or hypothesis, an embodiment of devices and methods may nonetheless be operative and useful.

[0056] Applicant has previously described systems and methods for electrowinning of metallic iron from iron-containing feedstocks such as iron-containing ores and waste materials as described for example in U.S. Pat. No. 11,767,604 (“the '604 patent”), which is incorporated herein by reference and attached as Appendix A. Some examples described in the '604 patent include subsystems or electrochemical cells referred to therein as “Acid Regeneration” (“AR cells”) cells or subsystems configured to reduce “ferric” (Fe3+) ions to “ferrous” (Fe2+) ions, and to regenerate acid (H+) consumed during leaching of the feedstock material(s). The '604 patent also describes various examples of “plating” cells configured to cathodically reduce iron ions to metallic iron which may be removed and recovered as a product. Some plating cells described in the '604 patent are configured to anodically oxidize ferrous ions to ferric ions while electroplating iron at the cathodes. Some plating cells described in the '604 patent are configured to anodically split water in order to evolve oxygen at the anodes while electroplating iron at the cathodes. The “cartridge” electrode configurations described herein may be configured for use in any of the plating cells and / or acid regeneration cells described n the '604 patent.

[0057] FIG. 1 (only) illustrates a prior art example electrowinning bath 100 containing a metal rich electrolyte 110 into which anodes A and cathodes C may be submerged.

[0058] FIG. 1 illustrates four anodes A and three cathodes C for simplicity of description, but any number of anodes and cathodes may be combined into a single bath. If both faces of each cathode are to be deposited with metal, the number of anodes will be one greater than the number of cathodes. The anodes A may be electrically connected to a positive polarity (+) of a power supply (not shown). Similarly, the cathodes C may be electrically connected to a negative polarity of the power supply. Anodes and cathodes are conventionally connected to the power supply by contacting a corresponding electrical contact along an edge of the bath 100 or other structures similarly situated.

[0059] The cathode-contacting electrolyte 110 (“catholyte”), often referred to as an enriched solution, a leachate, or a lixiviant, typically contains one or more dissolved metal species to be extracted by electrodeposition at the cathodes C while a charge-balancing oxidation reaction (or combination of reactions) occurs at the anodes A, typically under an applied electrical current. The electrolyte 110 generally flows into, through, and out of the bath 100 so as to continually replenish the dissolved metal in the bath 100 as it is deposited on the cathodes.

[0060] In some electrowinning systems, the anode-contacting electrolyte (“anolyte”) may be the same fluid as the cathode-contacting electrolyte, as shown for example in FIG. 1. In such cases, both anodes and cathodes are in contact with the common electrolyte and any dissolved ionic constituents or any undissolved (e.g., colloidal) solids carried in the electrolyte. In many cases, the expected dissolved and undissolved materials do not adversely affect the electrochemical reactions or the effects are acceptable within those systems.

[0061] However, in other systems it is desirable to use separate fluids for anolyte and catholyte, allowing for anodic and cathodic reactions while preventing bulk mixing of the separate electrolytes. In such systems, it is desirable to maintain separation of the anolyte and catholyte streams while flowing both through respective anode and cathode fluidic channels. Maintaining this separation calls for separate anolyte and catholyte conduits separately directing anolyte and catholyte into their respective reaction spaces (e.g., “anode chamber(s)” and “cathode chambers” or “plating baths”). In addition, a barrier may be used to separate the fluids while providing for electrochemical interactions by allowing transport of charge-balancing ions through the barrier. In such separated electrolyte systems, a separator (which may be a membrane) may be used as such a barrier.

[0062] In the field of electrochemical systems, and particularly in the field of electrowinning metals, electrochemical cells may be configured with anodes and / or cathodes that are easily removable from an electrochemical cell 200, as shown for example in FIG. 2. Removal may be facilitated by suspending anodes 210 and / or cathodes 212 from support bars 216 which extend over structures of the electrolyte 222 in the bath 220. In some embodiments, the support bars 216 may also provide electrical connections at which positive and negative electrical connections can be made between the electrodes and respective contacts and power supply. In some cases, a support bar (or a component thereof) may be referred to as a “bus bar” to indicate a role in electrical connections. In some embodiments, support bars and electrical bus bars may be integrated into a single structure.

[0063] Alternatively, support bar 216 structures and electrical bus bar structures 216 may be provided as separate components, which may be made of different materials optimized for mechanical strength and electrical conductivity, respectively. For example, support bars may be made of steel or composite materials with substantial mechanical strength, but relatively low electrical conductivity; while electrical bus bars may be made of copper or other materials with higher electrical conductivity but lower mechanical strength. Some examples are described below with reference to FIG. 7.

[0064] In some electrowinning systems, cathodes 212 are removed once a desired quantity of metal has been electroplated onto the surface. The electrowon metal may then be removed from the cathodes so that the cathodes may be returned to the bath 220 for a subsequent electroplating operation. Similarly, anodes 210 may be removable from the bath 220 for anode maintenance, anode replacement, bath maintenance, etc.

[0065] In the example of FIG. 2, the cathodes 216 may be submerged directly in a catholyte solution 222. However, maintaining separate electrolytes with removable anodes involves separate fluidic connections for a separate anolyte to flow through the anode electrodes 210 without mixing with the catholyte 222. To address this, various features and examples are provided herein for “cartridge” electrodes that contain flow-directing structures for flowing an electrolyte into, through, and out of the cartridge to facilitate the desired electrochemical reactions. In various implementations, such flow-through cartridge electrodes may be used as either anode or cathode, or both. Various features and examples of flow through cartridge electrodes are shown and described herein.

[0066] FIG. 3A is a cross-sectional illustration of an example cartridge electrode 300 (e.g., an anode in the configuration of FIG. 2 or a cathode in some other configurations) positioned between a pair of counter-electrodes 302 (e.g., cathodes in the configuration of FIG. 2 or anodes in some other configurations). The illustrated cartridge electrode 300 comprises a conductive structure 304, a reaction surface 306, and a separator 308. In the example of FIG. 3A, fluidic conduits 310 are provided as holes or conduits through or adjacent to the conductive structure 304 and the support structure 316.

[0067] The conductive structure 304 is generally configured to serve as a “current collector” for conducting electrical current between a reaction surface and an electrical source or load. The conductive structure 304 may comprise a metallic or non-metallic electrically conductive material of any form-factor and dimensions suitable for conducting electrons to or from a reaction surface 306. For example, the conductive structure 304 may comprise a metal such as copper, steel, stainless steel, titanium, other metals, a non-metal such as carbon or graphite, or any combination(s) of these.

[0068] The conductive structure 304 may comprise a single material or may be a composite, alloy, and / or assembly of multiple materials. In some embodiments, the conductive structure 304 comprises an electrically conductive material in the form of a solid rod or bar, a hollow tube, or a porous mesh, foam, felt, other porous conductive structure, or any combination(s) of these.

[0069] In various embodiments, the conductive structure may have any shape or configuration as needed for a particular application. For example, the conductive structure 304 may be planar as shown in FIG. 2 or FIG. 6, elongated as described below with reference to FIG. 7-FIG. 11, rod-shaped, bar-shaped, plate-shaped, or any combination of shapes and / or configurations.

[0070] In various embodiments, the reaction surface 306 may comprise a coating or layer of material in electrically conductive contact with the conductive structure 304 and having a surface suitable for promoting desired reactions. In some embodiments, the reaction surface 306 may be porous and / or featured to allow an electrolyte to flow over or through the reaction surface 306. The reaction surface 306 may comprise one or more additional material(s) that is bonded, welded, adhered, compressed, pressed, welded, crimped, or otherwise held in conductive contact with the conductive structure 304. In some embodiments, the reaction surface 306 may comprise one or more layers or elements of material and / or surface treatment. For example, a reaction surface may comprise a gas diffusion layer and a catalyst material. In some embodiments, the reaction surface 306 may include a layer of felt, foam, woven or unwoven fibers, felted fibers, wools, or other structures made of carbon or graphite in electrically conductive contact with the conductive structure 304.

[0071] According to various aspects, a reaction surface, such as but not limited to reaction surface 306, may be configured to maintain physical contact with the separator, such as but not limited to separator 308, during operation of the cartridge electrode even if and when the separator undergoes expansion or contraction. There are several non-limiting example configurations that facilitate the reaction surface maintaining contact with an expanding and / or contracting separator. In some aspects, for example, the cartridge electrode is assembled with the reaction surface having a constricted diameter that is less than its relaxed diameter, such that the reaction surface may expand as the separator expands during operation of the cartridge electrode. In various aspects, at least a portion of the reaction surface is configured to expand (or contract) as the separator expands (or contracts) to maintain at least partial physical contact between the reaction surface and the separator. In some aspects, for example, the reaction surface is configured to comprise fibers extending generally away from a cylinder axis of the conductive structure (e.g., approximately 10° C. to 90° C. off the cylinder axis, e.g., perpendicular thereto) where said fibers are constricted by the separator so as to expand with / against the separator if and when the separator itself expands or otherwise stretches away from the conductive structure. For example, in some aspects, reaction surface comprises fibers that undergo a change from a bent configuration to a less bent (or more straight) configuration if and when the separator expands or stretches away from the conductive structure, thereby the fibers maintaining physical contact with said separator. For example, in some aspects, reaction surface comprises fibers that undergo a change from a small angle between an axis of each fiber and a cylinder axis of the conductive structure to said angle increasing if and when the separator expands or stretches away from the conductive structure, thereby the fibers maintaining physical contact with said separator. For example, in some aspects, the conductive structure and the reaction surface may be configured as a brush with an electrical conductive central cylindrical stem forming the conductive structure and the brush fibers forming the reaction surface. In various aspects, said fibers are formed of any one or combination of materials as any reaction surface described herein. For example, in various aspects herein, said fibers are formed of one or more carbon allotropes. For example, in various aspects herein, said fibers are carbon fibers or are formed of carbon fibers.

[0072] Alternatively or in addition, the reaction surface 306 may comprise a surface treatment applied to the conductive structure 304, such as machining, knurling, channeling, etc. Such treatments may be applied for the purpose of increasing a reaction surface area, improving adhesion of a separate reaction surface layer, providing flow fields for directing flow of an electrolyte or other reactant, or others.

[0073] In some embodiments, a cartridge electrode may include a flow field comprising one or more structures configured to direct electrolyte flow along a desired path through or adjacent to the reaction surface. In some embodiments, a flow field (if present) may comprise grooves, channels, conduits, or other structures formed into one or more of the conductive structure 304, the reaction surface 306, and / or the separator 308. Alternatively, a flow field (if present) may comprise an additional structure interposed between a conductive structure 304 and a reaction surface 306 or between a reaction surface 306 and the separator 308.

[0074] The separator 308 may generally comprise an electrically non-conductive material suitable for preventing mixing of separate electrolytes while allowing transfer of charge-carrying ionic species. Example separator membranes may include porous membranes allowing for bi-directional migration of charged ions driven by electromotive force of the positively charged anode and the negatively charged cathode. Porous membranes may include woven or non-woven polymeric, ceramic, or other non-conductive materials with micro-scale or nano-scale pores. Alternatively, some separator membranes, referred to as ion-selective membranes (or ion-exchange membranes, IEMs), are configured to selectively allow and / or impede migration of specific ions such as anion exchange membranes, or “AEMs” configured to allow transport of anions while inhibiting or preventing transport of cations. Cation exchange membranes, or “CEMs” and proton exchange membranes (PEMs) are generally configured to allow transport of cations and / or protons while preventing or inhibiting transport of anions.

[0075] A separator useful in aspects herein, such as but not limited to separator 308, separator 406, and / or separator 908, can be a homogeneous material made up of a single polymer or ceramic material or the separator can be a heterogeneous material made up of a plurality of materials such as a plurality of polymers, a plurality of ceramic materials, or a combination of one or more polymers and one or more ceramic materials. For example, in some cases, a heterogeneous membrane may comprise a thermoplastic polymeric support structure embedded with particles or strands of one or more ion exchange materials. In a heterogeneous material separator, the support structure may be substantially impermeable to ionic transport while the ion exchange resin provides pathways for the transport of anions or cations through the membrane.

[0076] By contrast a homogeneous membrane may comprise a single polymer providing both mechanical and ion transport properties. A separator useful in aspects herein, such as but not limited to separator 308, separator 406, and / or separator 908, may comprise a single layer or multiple layers of homogeneous or heterogeneous material(s). A separator useful in aspects herein, such as but not limited to separator 308, separator 406, and / or separator 908, may be configured in a flat sheet, tube, or other form factor as suitable for a particular cartridge electrode configuration.

[0077] FIG. 3A schematically illustrates (in a cross-sectional view) some features of a flow-through cartridge electrode 300. The flow-through electrode and a pair of counter-electrodes are shown submerged in a bath 312 containing an electrolyte 314. The cartridge electrode 300 and the cartridge electrolyte (within flow channels 310) is separated from the counter-electrodes 302 and the bath electrolyte 314 by a separator 308 adjacent to the reaction surface 306 and conductive structure 304. The illustrated flow path of a flow-through electrolyte 310 is merely schematic and is not intended to limit the scope of possible embodiments. In some embodiments the flow-through electrolyte flows through the space between the conductive element 304 and the separator 308.

[0078] The illustrated flow-through cartridge electrode 300 includes flow channels 310 for directing anolyte into, through, and out of the cartridge electrode chamber 300 to replenish anodic reactants during operation of the electrochemical cell. In the example shown in FIG. 3A, electrolyte may flow into a supply channel 310, then into a reaction space 307 between a separator membrane 308 and a conductive structure 304 and / or reaction surface 306. While the arrows shown in FIG. 3A suggest a particular flow path, any other flow paths or configurations may be employed to direct electrolyte into, through, and out of a reaction chamber within the flow-through cartridge electrode 300.

[0079] In many electrochemical systems, maintaining a separator membrane at a consistent distance to both electrode surfaces across the “active area” (as defined above) is desirable to achieve efficient and consistent electrochemical reactions, which is achieved in various aspects herein. For example, FIG. 3A illustrates a preferred position, according to various aspects herein, of a separator membrane 308 as electrolyte flows through a space between the conductive structure 304 and the separator 308, wherein the separator 308 is consistently spaced from the conductive structure 304 across the area of the interface between the two.

[0080] Many IEM polymers and ceramics lack sufficient mechanical strength, tensile strength, and creep resistance to withstand substantial fluid pressures exerted by electrolytes flowing in an electrowinning cell without deformation or tearing. In general, as the active area of an electrochemical cell increases, so does the distance between membrane attachments (e.g., the edges of a sheet) and a central portion of the membrane sheet. A membrane may generally be supported at peripheral edges so as to allow the entire membrane area to be available for ionic transport.

[0081] As shown in the two-dimensional cross-sectional view of FIG. 3B, a separator membrane 308 supported at its peripheral edges 320 may tend to “balloon” outwards away from a conductive structure 304 and / or a reaction surface 306 (and / or towards a counter-electrode 302) as a result of fluid pressures in the electrolyte space 307 between the conductive structure 304 and the membrane 308. Movement of the membrane may also be caused by local weakness, local temperature variations, or un-controlled variations in flow. Some of these challenges can cause feedback loops creating weakened membrane sections or even perforations.

[0082] Various approaches can be taken to mitigate these challenges, but some have undesirable drawbacks. For example, support structures may be positioned on one or both sides of a separator membrane in order to mechanically support a central section of the membrane. However, those support structures tend to add distance between anode and cathode, resulting in increased electrical resistance, increased voltage, and decreased energy efficiency of the electrochemical cell. Membrane support structures will also tend to block some regions of the separator membrane, leaving those regions unable to participate in the desired electrochemical reactions.

[0083] With reference to FIG. 4, another configuration for supporting a separator is to establish and maintain a pressure difference across the separator in order to press the separator onto one of the electrode faces, thereby ensuring consistent positioning of the membrane. FIG. 4 illustrates an example electrochemical cell 400 (e.g., an electrowinning cell or an acid regeneration cell), comprising a cell container 410 in which a first electrode 402 is positioned within a first chamber 412 containing a first electrolyte 416. A separator membrane 406 separates the first chamber 412 from a second chamber 414, which contains a second electrolyte 418 and a second electrode 404. A first electrolyte 416 on the first-electrode-side of the separator 406 may be held at a first pressure that is greater than a second pressure of a second electrolyte 418 on the second-electrode-side of the separator 406. This pressure difference will tend to deflect the separator 406 towards the second electrode 404. In the illustrated example, the second electrode 404 may comprise a plurality of recesses 408 providing a space for electrolyte between the electrode 404 and the separator 406. The recesses 408 may comprise longitudinal channels or other spaces between structures of the electrode 404 (which may include one or more conductive structures and / or one or more reaction surfaces as described above). For example, the electrode 404 may comprise a (woven or non-woven) mesh, a corrugated sheet, a channeled sheet, a perforated sheet, a felt, or other structures allowing flow of electrolyte through and / or around structures of the electrode 404.

[0084] In some embodiments, the configuration of FIG. 4 may be implemented in an electroplating bath such as that described above with reference to FIG. 2, in which case, the first electrode 402 may be an electrolytic anode (e.g., for performing a water-splitting oxygen evolution reaction (OER) or another oxidation reaction such as oxidation of Fe2+ ions to Fe3+ ions) and the second electrode 404 may be an electrolytic cathode for performing reduction of one or more metal cations to form a metallic deposit (e.g., iron, zinc, copper, cobalt, nickel, etc.) on the second electrode. In other embodiments, the first electrode may be an electrolytic cathode, and the second electrode 404 may be an electrolytic anode. In still other electrochemical cell configurations, the first electrode 402 may be a galvanic cathode and the second electrode 404 may be a galvanic anode. Or the first electrode 402 may be a galvanic anode and the second electrode 404 may be a galvanic cathode.

[0085] In various embodiments, a pressure difference between electrolytes may be selected to be sufficient to retain the separator in a desired position relative to one or both electrodes. Therefore, in many cases, an excess pressure on a high-pressure side of a separator should be at least as great as an expected pressure variation of electrolyte on the low-pressure side. For example, a high-pressure side electrolyte may be maintained at a pressure of at least 0.05 bar to 1 bar greater than an anticipated variation in pressure on the low-pressure side. In some embodiments, a hydraulic pressure of a low-pressure side electrolyte may be monitored and pressure of the high-pressure electrolyte may be adjusted in response to such monitoring in order to maintain a pressure difference of 0.01 bar to 1 bar or more. In other embodiments, a high-pressure side hydraulic pressure may be established at a consistent pressure selected to be at least 0.1 to 1 bar or more greater than a maximum hydraulic pressure expected on the low-pressure side.

[0086] Various methods and systems may be used to establish and maintain a pressure difference as described above with reference to FIG. 4. For example, in some embodiments, a suction pump may be used to apply a negative pressure to the second electrolyte 418 as it is drawn out of the second electrode chamber 414. Any suitable suction pump type may be used, such as centrifugal pumps, submersible pumps, jet pumps, diaphragm pumps, positive displacement pumps, or others.

[0087] FIG. 5 is a schematic illustration of an electrochemical system 500 comprising a suction pump 502 positioned downstream of an outlet from second electrode chambers 512 of a group of electrodes within an electrochemical system 500. The first electrolyte 520 may be driven through the electrochemical system 500 by any suitable pump 504 or gravity-driven flow system. The second electrolyte 522 may be drawn out of the second electrode chambers 512 at a sufficiently low pressure relative to the first electrolyte 520.

[0088] For example, the electrochemical system 500 of FIG. 5 may be configured as an electroplating bath (such as that shown in FIG. 2) in which the lower pressure electrolyte 522 is the anode electrolyte (anolyte) which is drawn out of the anodes 512 by a suction pump 502 while the higher-pressure cathode electrolyte (catholyte) 520 may be pumped through the plating bath by any suitable pump 504, provided that the anolyte is maintained at a lower pressure than the catholyte.

[0089] In an alternative configuration, the system 500 of FIG. 5 may be arranged as an acid regeneration cell stack in either a monopolar or bipolar configuration. In such embodiments, the lower-pressure electrolyte 512 is the cathode electrolyte (catholyte), which may be withdrawn from the cathode chambers 512 by a suction pump 502. In such embodiments, the higher-pressure electrolyte 520 is the anode electrolyte (anolyte), which may be pumped through the anode chamber 510 by any suitable pump 504 or gravity driven flow system. In some embodiments, the pressure of the higher-pressure electrolyte may vary and the suction pump may be configured to maintain a lower pressure than the lowest variance of the higher-pressure electrolyte. Alternatively, the vacuum pump may be controlled in response to a measured pressure of the higher-pressure electrolyte such that at least the desired pressure difference is maintained.

[0090] In some embodiments, an electrolyte pressure difference may be maintained by maintaining a difference in hydrostatic head height between electrolytes on opposite sides of the separator. FIG. 6 schematically illustrates an electrochemical cell 600 in which a first electrolyte 602 in a bath 604 surrounds a flow-through cartridge electrode 610 through which a second electrolyte flows from a cartridge inlet 612 to a cartridge outlet 614. The first electrolyte 602 in the bath 604 may flow into the bath via an inlet 616 and out of the bath via corresponding outlet at an opposite end of the bath (e.g., in line with the inlet 616). The bath electrolyte surface level 620 may be maintained by controlling a rate of flow of the first electrolyte into and out of the bath. As shown in FIG. 6, the bath electrolyte surface level 620 may be maintained at a level above both the second electrolyte inlet 612 and the second electrolyte outlet 614.

[0091] The cartridge electrode of FIG. 6 is supported by support bar 624, electrolyte flows from the inlet 612, into the vertical downcomer 630, then through the bottom manifold 632, which directs the electrolyte up through the active area of the electrode 610 and then out of the cartridge electrode through the outlet conduit 615 to the bath outlet 614.

[0092] Another approach to consistently maintaining a separator within a desired distance to an electrode is to use a separator membrane in the shape of a tube. This takes advantage of the “hoop stress” of a circular tube, meaning the pressure within a section of a circular tube should exert a consistent stress across the circumference of the tube. This approach takes maximum advantage of a membrane material's inherent strength. In some embodiments, a cartridge electrode comprises an array of elongated electrode elements, each comprising a conductive structure, a reaction surface, and a tubular membrane.

[0093] FIG. 7, FIG. 8, and FIG. 11 illustrate examples of a cartridge electrode 700 comprising an array of elongated elements 702. Each elongated element 702 includes a conductive structure, a reaction surface, and a membrane as described above. In a cylindrical elongated element configuration, the conductive structure, reaction surface, and membrane may be arranged concentrically with one another. Each elongated element is generally shown extending vertically between an upper support bar 710, an upper manifold 712 and a lower manifold 714. The support bar 710 is also shown with an electrical bus bar section 711 and electrical connections 715 to each elongated electrode element 702. In some aspects, the lower manifold may be an in-flow manifold configured to provide and direct an electrolyte through the reaction space of each of the elongated electrode elements and the upper manifold may be an out-flow manifold configured to receive the electrolyte exiting each of the reaction spaces of the elongated electrode elements. In some aspects, the upper manifold may be an in-flow manifold configured to provide and direct an electrolyte through the reaction space of each of the elongated electrode elements and the lower manifold may be an out-flow manifold configured to receive the electrolyte exiting each of the reaction spaces of the elongated electrode elements.

[0094] With reference to FIG. 7, in some embodiments, an electrolyte may be directed into an inlet port 722, downward through a first vertical conduit 724, through a lower manifold 714 configured to distribute electrolyte to the electrode elements 702, then up to the upper manifold 712 and out through an outlet port 726. In some embodiments, electrolyte may be driven down through two (or more) vertical conduits 724, 725. In some embodiments, electrolyte may be driven into the bottom manifold 714, up through the electrode elements 702, and out through an upper outlet 726.

[0095] In general, only the elongated electrode elements 702 need be electrochemically active and therefore electrically polarized by electrical connection to an electrical load or source. Structures of a cartridge electrode 700 that need not be electrochemically active, such as manifolds 712, 714, vertical conduits 724, 725, inlet and outlet ports 722, 726, and other similar structures, may be made of one or more non-conductive material such as polymeric materials. Polymeric materials suitable for acidic electrolytes may include polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), polyvinyl fluoride (PVF), acetal, ethylene chlorotrifluoroethylene (ECTFE), polyamide-imide (PAI), polyphenylene sulfide (PPS), high-density polyethylene (HDPE), ethylene chlorotrifluoroethylene (ECTFE), or others. If an alkaline electrolyte is to be used, suitable polymeric materials may include polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), polyvinyl fluoride (PVF), acetal, ethylene chlorotrifluoroethylene (ECTFE), polyamide-imide (PAI), polyphenylene sulfide (PPS), polysulfone (PSU), polyphenylsulfone (PPSF or PPSU), or others.

[0096] FIG. 9 and FIG. 10 illustrate components of some embodiments of elongated elements 702. FIG. 9 is a cross-sectional view of an example elongated element segment 702. The elongated element 702 comprises a central conductive structure 902 surrounded by a reaction surface 904, which is in turn surrounded by a separator 908.

[0097] In some embodiments, the central conductive structure 902 comprises a solid rod of one or more electrically conductive materials such as metals (e.g., iron, steel, stainless steel, titanium, magnesium or others), carbon, graphite, graphene, or other electrically conductive non-metal. The conductive structure 902 may be cylindrical, although non-cylindrical shapes (e.g., square, pentagonal, hexagonal, heptagonal, octagonal, etc.) may also be used. In some embodiments, the conductive structure 902 may have a hollow center and / or a central core of a different material than an outer portion of the conductive structure 902.

[0098] The reaction surface 904 is advantageously an electrically conductive and porous material through which electrolyte may flow along the length of the elongated element 702. Example reaction surface materials may include one or more conductive materials in a felt, foam, mesh, fabric, wool, and / or other porous form-factor. In some embodiments, the reaction surface may comprise a stack of discs slid over the conductive structure 902. In some embodiments, the reaction surface 904 may comprise a sheet of material wrapped around the conductive structure 902. In some embodiments, the reaction surface 904 may comprise one or more strips of material wrapped around a mandrel or the conductive structure 902 in a spiral pattern. In some embodiments, the reaction surface 904 may be sprayed or dip-coated onto the conductive structure 902.

[0099] In some embodiments, a reaction surface 904 material may be secured to the conductive structure 902 in a manner that permits electrical conductivity between the conductive structure 902 and the reaction surface 904. For example, the reaction surface 904 material may be adhered to the conductive structure 902 with a conductive adhesive such as a conductive epoxy, resin, silicone, or others. In some embodiments, the reaction surface 904 material may be soldered, brazed, or welded to the conductive structure 902. In other embodiments, the reaction surface 904 material may simply be connected to the conductive structure by a compressive force. In some embodiments, the reaction surface material may be mechanically attached to the conductive structure 902 such as by being pinched into channels or other constrictions in the conductive structure 902 or in additional structures (e.g., collars or sleeves) conductively secured to the conductive structure 902.

[0100] The separator 908 may generally comprise an electrically non-conductive material suitable for preventing mixing of separate electrolytes while allowing transfer of charge-carrying ionic species. Example separator membranes may include porous membranes allowing for bi-directional migration of charged ions driven by electromotive force of the positively charged anode and the negatively charged cathode. Porous membranes may include woven or non-woven polymeric, ceramic, or other non-conductive materials with micro-scale or nano-scale pores. Alternatively, some separator membranes, referred to as ion-selective membranes (or ion-exchange membranes, IEMs), are configured to selectively allow and / or impede migration of specific ions such as anion exchange membranes, or “AEMs” configured to allow transport of anions while inhibiting or preventing transport of cations. Cation exchange membranes, or “CEMs” and proton exchange membranes (PEMs) are generally configured to allow transport of cations and / or protons while preventing or inhibiting transport of anions.

[0101] The separator 908 can be a homogeneous material made up of a single polymer or ceramic material, or a heterogeneous material made up of multiple polymers and / or ceramic materials. For example, in some cases, a heterogeneous membrane may comprise a thermoplastic polymeric support structure embedded with particles or strands of one or more ion exchange materials. In such a heterogeneous structure, the support structure may be substantially impermeable to ionic transport while the ion exchange resin provides pathways for the transport of anions or cations through the membrane. By contrast a homogeneous membrane may comprise a single polymer providing both mechanical and ion transport properties. The separator 908 may comprise a single layer or multiple layers of homogeneous or heterogeneous material. The separator 908 may be configured in a flat sheet, tube, or other form factor as suitable for a particular cartridge electrode configuration. In some embodiments, a separator may comprise multiple layers, such as a mechanical support layer with high tensile strength and high porosity, and an ion-exchange layer with low tensile strength but high conductivity to ionic transport.

[0102] In various embodiments, a separator membrane 908 may be provided in a cylindrical form-factor and may be in physical contact with the reaction surface 904 along a substantial portion of the separator membrane 908. In some embodiments, a cylindrical separator membrane may be made by spiral-winding a strip of separator material on a mandrel, and adhering overlapping sections of the membrane together. Depending on the material(s) of the membrane, the overlapping sections may be adhered by thermal welding, ultrasonic welding, solvent bonding, adhesives, additive welding, or other processes.

[0103] Cylindrical separator membranes may also be made by wrapping elongated strips of membrane material into tubes and forming linear seams parallel to the longitudinal axis of the strip. Such a linear seam may be secured by thermal welding, ultrasonic welding, solvent bonding, adhesives, additive welding, or other processes. Cylindrical separator membranes may also be made by extruding a membrane material as a continuous cylinder which may be cut to a desired length.

[0104] FIG. 9 also shows a flow diffusion fitting 910 at one end of the elongated element 702. The flow diffusion fitting 910 is configured to seal the separator 908 to electrolyte conduits connected to the upper and lower manifolds 712, 714 (FIG. 7), thereby sealing the reaction spaces inside the separators 908. The upper flow diffusion fittings 910 may generally include structures for allowing fluid to flow through the fitting 910 while providing electrical connection from connectors 715 (FIG. 7) to the conductive elements 902 within the elongated electrode elements 702.

[0105] FIG. 10 illustrates an example flow diffuser fitting 910 comprising a central conductor 150, a peripheral attachment ring 152, and flow diffusion channels 154 configured to direct electrolyte into the reaction space between the conductive elements and the separators of an elongated electrode element 702.

[0106] In a cartridge electrode such as that shown in FIG. 7-FIG. 9, electrolyte may flow from a manifold (e.g., either a top manifold 712 or a bottom manifold 714 in FIG. 7), through a flow diffusion fitting 910, and into the reaction space between the conductive structure 902 and the separator 908 occupied by the reaction surface 904. Electrochemical reactions will tend to occur on the reaction surface as charge-carrying ions pass through the separator 908 into the electrolyte within the reaction space as electrolyte continues to flow along the length of the elongated element 702. When the electrolyte reaches the opposite end of the elongated element 702, it may pass through a second flow diffusion fitting 910 and into the opposite manifold. In various embodiments, the second flow diffusion fitting 910 may be configured identically to the first flow diffusion fitting or differently.

[0107] The cartridge electrodes of FIG. 7, FIG. 8, and FIG. 11 include 12 elongated electrode elements. In other embodiments, a cartridge electrode of the same or a similar type may include any number of elongated electrode elements in any length, diameter, or cross-sectional size as needed for a particular application, various examples of which are described herein.

[0108] In some embodiments, each elongated element 702 may be configured with a flow field arranged to direct electrolyte flowing therethrough in a desired path. For example, some flow fields may be configured to direct electrolyte more circumferentially than axially at some points along the length of the elongated elements 702 while directing electrolyte more axially than circumferentially at other points along the length. In this way, the residence time of the electrolyte at different axial locations may be changed to match expected rates of reactant consumption with expected rates of reactant supply along the length of the elongated elements 702. In some embodiments, flow fields may be formed by forming a pattern in the conductive structures 902, reaction surfaces 904, and / or the separators 908. Alternatively or in addition, flow fields may be provided by additional structures within or adjacent to the reaction space through which electrolyte flows. In various aspects herein, a cartridge electrode may be configured to comprise one or more radial electrolyte flow channels or flow paths. Optionally, a radial flow channel may be formed by radially providing a material such as, but not limited to, a filament, at least partially around a rod or cylindrical structure or component of the cartridge. Optionally, for example, a radial flow path or channel for electrolyte may be formed via a material radially or spirally wound around a cylindrical conductive structure described throughout herein. The radially provided material may be, for example, a polymer filament spirally wound around a central cylindrical structure or component. A radial flow channel may be configured such that an electrolyte flowing from one end of the cartridge electrode to the other end thereof will flow radially around a cylindrical structure or component of the cartridge electrode. A radial flow channel may provide benefits of enhancing mixing within an electrolyte, such as to enhance reactant transport to reaction surface and product withdrawal, and / or controlling electrolyte flow velocity or transport rate.

[0109] As shown in FIG. 8, in some embodiments, one or more sheets 850 of porous metallic material may be provided to cover both planar faces outside of the array of elongated elements 702. In some embodiments, such sheets 850 may be secured to the upper and lower manifolds 712, 714. The sheet 850 may be made of a metallic mesh, metallic foam, or perforated metallic sheet made of a metal resistant to degradation by the electrolyte in use. For example, the sheet may be made of a stainless steel, titanium, or others. By securing the sheet 850 to non-conductive structures of the cartridge electrode, it may be electrically non-polarized when in use. When cartridge electrodes with cover sheets are used as anodes in an electrowinning system, the sheets may beneficially prevent dendrites from reaching and damaging the elongated element electrodes 702.

[0110] While examples are shown and described herein with reference to cylindrical elongated elements and membranes, similar benefits may be achieved with other cross-sectional shapes, such as elliptical, ovoid, polygonal, or others. For example, any or all of the conductive structure 902, reaction surface 904, or separator 908 may have a non-cylindrical elongated shape. Also, while the cartridge electrodes of FIG. 7, FIG. 8, and FIG. 11 are shown with long axes of the elongated elements oriented vertically, they may alternatively be oriented horizontally or at any angle between vertical and horizontal.

[0111] As shown in FIG. 11, cartridge electrodes such as those shown in FIG. 7 and FIG. 8 may be paired with planar electrodes 212 in various electrochemical cell systems. For example, in some embodiments, the arrangement of FIG. 11 may represent an electrowinning cell in which the cartridge electrode 700 is an anode through which an anolyte may flow as described above, while the planar electrodes 212 may be cathodes exposed to the bath electrolyte 222 which may contain dissolve metallic ions to be electroplated onto the cathodes. In some embodiments, electroplating cathodes may be masked with a chemically-resistant non-conductive material in order to produce electroplated segments of a desired shape, such as circles, squares, rectangles, polygons, etc.

[0112] Alternatively, the arrangement of FIG. 11 may represent an acid regeneration cell such as those described in the '604 patent. In such an arrangement, the cartridge electrode 700 is a cathode through which a catholyte electrolyte (e.g., containing ferric ions to be cathodically reduced to ferrous ions) may flow, and the bath electrolyte 222 may be an anolyte from which oxygen may be evolved in an anodic water splitting reaction.

[0113] While the '604 patent and some examples herein are described with reference to iron electrowinning systems, the cartridge electrodes described herein may also be used for other applications, such as electrowinning of other metals (e.g., Cu, Zn, Ni, Co, Au, Ag, Cd, rare earth elements, or others). Alternatively, cartridge electrodes such as those described herein may be configured for electrochemical water electrolysis cells, flow batteries, electrosynthesis cells, or other electrochemical systems.Certain Aspects and Embodiments

[0114] Various aspects are contemplated and disclosed herein, a plurality of which is set forth in the paragraphs below. It is explicitly contemplated and disclosed that any aspect or portion thereof can be combined to form an aspect. In addition, it is explicitly contemplated and disclosed that: any reference to Aspect 1 includes reference to Aspects 1a, 1b, 1c, 1d, 1e, and / or 1f; any reference to Aspect 19 includes reference to Aspects 19a and / or 19b; and so on (any reference to an aspect includes reference to that aspect's lettered versions). Moreover, the terms “any preceding aspect” and “any one of the preceding aspects” means any aspect that appears prior to the aspect that contains such phrase (for example, the sentence “Aspect 4: The electrode or method of any of the preceding Aspects . . . ” means that any Aspect prior to Aspect 4 is referenced, including letter versions, including aspects 1a through 3). For example, it is contemplated and disclosed that, optionally, any method, any step, any system, any subsystem, any composition, etc., according to any of the below aspects may be useful with or combined with any other aspect(s) provided below. Further, for example, it is also contemplated and disclosed that any embodiment or aspect described above may, optionally, be combined with any of the below listed aspects.

[0115] Aspect 1a: A cartridge electrode for use in an electrochemical system, the cartridge electrode comprising:

[0116] a support bar at a top portion of the apparatus;

[0117] a plurality of elongated electrode elements, each elongated electrode element comprising:

[0118] a conductive structure;

[0119] a tubular separator;

[0120] a reaction space between the conductive structure and the separator; and

[0121] a reaction surface within the reaction space;

[0122] an in-flow manifold configured to direct a cartridge electrolyte through the reaction space of each of the elongated electrode elements; and

[0123] an out-flow manifold configured to receive the cartridge electrolyte exiting each of the reaction spaces of the elongated electrode elements.

[0124] Aspect 1b: A method for operating an electrochemical system, the method comprising:performing an electrochemical oxidation reaction or an electrochemical reduction reaction at cartridge electrode, the cartridge electrode comprising:a plurality of elongated electrode elements, each elongated electrode element comprising:

[0126] a conductive structure;

[0127] a tubular separator;

[0128] a reaction space between the conductive structure and the separator; and

[0129] a reaction surface within the reaction space;

[0130] an in-flow manifold configured to direct a cartridge electrolyte through the reaction space of each of the elongated electrode elements; andan out-flow manifold configured to receive the cartridge electrolyte exiting each of the reaction spaces of the elongated electrode elements.

[0131] Aspect 1c: The electrode or method of Aspect 1 comprising a support bar configured to retain the elongated electrode elements. Aspect 1d: The electrode or method of Aspect 1 comprising a support bar configured to retain the elongated electrode elements directly or indirectly. Aspect 1e: The electrode or method of Aspect 1 comprising a support bar configured to retain the elongated electrode elements, the support bar being at a top portion of the system. Aspect 1f: The electrode or method of Aspect 1 comprising a support bar configured to retain the elongated electrode elements and being directly or indirectly in physical contact with each of the elongated electrode elements.

[0132] Aspect 2: The electrode or method of Aspect 1, wherein the separator separates the cartridge electrolyte from a counter-electrolyte outside of the separators.

[0133] Aspect 3: The electrode or method of Aspect 1 or Aspect 2, wherein the separator membrane is electronically non-conductive and ionically conductive.

[0134] Aspect 4: The electrode or method of any of the preceding Aspects, wherein the reaction surface comprises a porous electrically conductive structure.

[0135] Aspect 5: The electrode or method of any of the preceding Aspects, wherein the reaction surface comprises a mesh, a felt, or a foam of an electrically conductive material.

[0136] Aspect 6: The electrode or method of any of the preceding Aspects, wherein the reaction surface comprises carbon, graphite, graphene, or a combination thereof.

[0137] Aspect 7: The electrode or method of any of the preceding Aspects, wherein each conductive structure is electrically connected to the support bar.

[0138] Aspect 8: The electrode or method of any of the preceding Aspects, wherein each conductive structure is cylindrical in shape.

[0139] Aspect 9: The electrode or method of any of the preceding Aspects, wherein the tubular separator comprises an ion-exchange resin.

[0140] Aspect 10: The electrode or method of any of the preceding Aspects, wherein the tubular separator comprises an anion exchange resin.

[0141] Aspect 11: The electrode or method of any of the preceding Aspects, wherein the tubular separator comprises a cation exchange resin.

[0142] Aspect 12: The electrode or method of any of the preceding Aspects, wherein the in-flow manifold is positioned below the plurality of elongated electrode elements.

[0143] Aspect 13: The electrode or method of any of the preceding Aspects, wherein the in-flow manifold is positioned above the plurality of elongated electrode elements.

[0144] Aspect 14: The electrode or method of any of the preceding Aspects, further comprising a flow diffuser coupling each elongated electrode element to the in-flow manifold.

[0145] Aspect 15: An electrowinning system comprising a plurality of cartridge electrodes as recited in any of Aspects 1-14, said cartridge electrodes being electrically polarized as electrolytic anodes and positioned in a catholyte bath adjacent to a plurality of cathode electrodes configured to receive an electrodeposited metal.

[0146] Aspect 16: The system or method of Aspect 15, wherein the electrodeposited metal is iron.

[0147] Aspect 17: An acid regeneration system comprising a plurality of cartridge electrodes as recited in any of Aspects 1-4, said cartridge electrodes being electrically polarized as electrolytic cathodes and positioned in an anolyte bath and positioned adjacent to a plurality of anodes.

[0148] Aspect 18: The system or method of Aspect 17, wherein the anodes are polarized at an anodic potential sufficient to perform an oxygen evolution reaction.

[0149] Aspect 19a: An electrochemical system in which a first electrode is in contact with a first electrolyte, a second electrode is in contact with a second electrolyte; the first electrolyte and the second electrolyte being separated by an ionically conductive separator; wherein a position of the separator relative to one of the electrodes is maintained by maintaining a pressure differential between the first electrolyte and the second electrolyte.

[0150] Aspect 19b: A method for operating an electrochemical system, the method comprising performing an electrochemical oxidation reaction or an electrochemical reduction reaction at an electrode of the electrochemical system, wherein the system comprises: a first electrode is in contact with a first electrolyte, a second electrode is in contact with a second electrolyte; the first electrolyte and the second electrolyte being separated by an ionically conductive separator; wherein a position of the separator relative to one of the electrodes is maintained by maintaining a pressure differential between the first electrolyte and the second electrolyte.

[0151] Aspect 20: The system or method of Aspect 19, wherein the pressure difference is maintained by a vacuum pump or a suction pump.

[0152] Aspect 21: The system or method of Aspect 19, wherein the pressure difference maintained by a difference in surface level between the first electrolyte and the second electrolyte.

[0153] Aspect 22a: The system, electrode, or method of any preceding Aspect, wherein the cartridge electrolyte follows a radial or spiral flow path within the cartridge electrode. Aspect 22b: The method of any preceding Aspect, comprising flowing the cartridge electrolyte radially or spirally within the cartridge electrode. Aspect 22c: The system or method of any preceding Aspect, wherein the cartridge electrolyte follows a radial or spiral flow path directly or indirectly around the conductive structure, the conductive structure having a cylindrical shape.

[0154] Aspect 23a: The system, electrode, or method of any preceding Aspect, wherein the tubular separator is a heterogeneous material. Aspect 23b: The system or method of any preceding Aspect, wherein the tubular separator comprises a heterogeneous material. Aspect 23c: The system or method of any preceding Aspect, wherein the tubular separator is formed of a heterogeneous material comprising one or more polymers and one or more ceramic materials.

[0155] Aspect 24a: The system, electrode, or method of any preceding Aspect, wherein the conductive structure and the tubular separator are coaxial. Aspect 24b: The system or method of any preceding Aspect, wherein each of the conductive structure and the tubular separator independently has a cylindrical shape and wherein the conductive structure and the tubular separator are concentric.

[0156] Aspect 25: The system, electrode, or method of any preceding Aspect, wherein each of the elongated electrode elements is parallel (to within approximately 5°) with respect to each other elongated electrode element.

[0157] Aspect 26: The system, electrode, or method of any preceding Aspect, wherein the electrochemical system is a metal electrowinning (or, metal electroplating) system or wherein the electrochemical system comprises a metal electrowinning cell.

[0158] Aspect 27: The system, electrode, or method of Aspect 26, wherein the each of the elongated electrode elements comprises an anode of the electrochemical system.

[0159] Aspect 28: The system, electrode, or method of any preceding Aspect, wherein the reaction surface is configured to maintain at least partial physical contact with the conductive structure and concurrently at least partial physical contact with the tubular separator during operation of the electrochemical system.

[0160] Aspect 29: The system, electrode, or method of any preceding Aspect, wherein each elongated electrode element is provided vertically between the in-flow manifold and the out-flow manifold.

[0161] Aspect 30: The system, electrode, or method of any preceding Aspect, wherein each elongated electrode is approximately parallel (optionally within approximately 20° of parallel) with respect to each other elongated electrode.Statements Regarding Incorporation by Reference and Variations

[0162] All references throughout this application, for example patent documents including issued or granted patents or equivalents; patent application publications; and non-patent literature documents or other source material; are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in this application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).

[0163] The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of any particular claimed invention. Thus, it should be understood that although inventions have been specifically disclosed by preferred embodiments, exemplary embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of inventions as defined by the appended claims. The specific embodiments provided herein are examples of useful embodiments of the inventions and it will be apparent to one skilled in the art that the inventions may be carried out using a large number of variations of the devices, device components, methods steps set forth in the present description. As will be obvious to one of skill in the art, methods and devices useful for the present methods can include a large number of optional composition and processing elements and steps.

[0164] As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise. Thus, for example, reference to “a cell” includes a plurality of such cells and equivalents thereof known to those skilled in the art. As well, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably. The expression “of any of claims XX-YY” (wherein XX and YY refer to claim numbers) is intended to provide a multiple dependent claim in the alternative form, and in some embodiments is interchangeable with the expression “as in any one of claims XX-YY.”

[0165] When a group of substituents is disclosed herein, it is understood that all individual members of that group and all subgroups, including iron oxide materials of an ore or structural and compositional polymorphs of the group members, are disclosed separately. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and sub-combinations possible of the group are intended to be individually included in the disclosure. When a compound is described herein such that a particular isomer, enantiomer or diastereomer of the compound is not specified, for example, in a formula or in a chemical name, that description is intended to include each isomers and enantiomer of the compound described individual or in any combination. Additionally, unless otherwise specified, all isotopic variants of compounds disclosed herein are intended to be encompassed by the disclosure. For example, it will be understood that any one or more hydrogens in a molecule disclosed can be replaced with deuterium or tritium. Isotopic variants of a molecule are generally useful as standards in assays for the molecule and in chemical and biological research related to the molecule or its use. Methods for making such isotopic variants are known in the art. Specific names of compounds are intended to be exemplary, as it is known that one of ordinary skill in the art can name the same compounds differently.

[0166] With regard to salts of the compounds herein, one of ordinary skill in the art can select from among a wide variety of available counterions those that are appropriate for preparation of salts of this invention for a given application. In specific applications, the selection of a given anion or cation for preparation of a salt may result in increased or decreased solubility of that salt.

[0167] Every device, system, subsystem, method, process, component, and / or combination of components, described or exemplified herein can be used to practice any claimed invention(s), unless otherwise stated.

[0168] Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.

[0169] All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the disclosed devices, systems, methods, and processes pertain. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art as of their publication or filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art. For example, when composition of matter are claimed, it should be understood that compounds known and available in the art prior to Applicant's inventions, including compounds for which an enabling disclosure is provided in the references cited herein, are not intended to be included in the composition of matter claims herein.

[0170] As used herein, “comprising” is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, “consisting of” excludes any element, step, or ingredient not specified in the claim element. As used herein, “consisting essentially of” does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms “comprising”, “consisting essentially of” and “consisting of” may be replaced with either of the other two terms. The claimed inventions illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

[0171] One of ordinary skill in the art will appreciate that starting materials, reagents, synthetic methods, purification methods, analytical methods, and assay methods other than those specifically exemplified can be employed in the practice of the claimed inventions without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in these inventions.

Examples

Embodiment Construction

[0055]In the following description, numerous specific details of devices, device components and methods are set forth to provide a thorough explanation of the precise nature of the various inventions described herein. It will be apparent, however, to those of skill in the art that the various inventions can be practiced without these specific details. Without wishing to be bound by any particular theory, there may be discussion herein of beliefs or understandings of underlying principles relating to the devices and methods disclosed herein. It is recognized that regardless of the ultimate correctness of any mechanistic explanation or hypothesis, an embodiment of devices and methods may nonetheless be operative and useful.

[0056]Applicant has previously described systems and methods for electrowinning of metallic iron from iron-containing feedstocks such as iron-containing ores and waste materials as described for example in U.S. Pat. No. 11,767,604 (“the '604 patent”), which is incor...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 63 / 757,142, filed Feb. 11, 2025, which is incorporated herein by reference in its entirety for all purposes.BACKGROUND

[0002] Electrochemical methods for extracting and / or purifying metals from one or more feedstock materials may be commonly referred to as “electrowinning” or “electro-refining.” For example, metals such as zinc and copper are commonly extracted from feedstocks by acid leaching, and the metals are “electroplated” onto cathodes while hydrolyzing water to produce oxygen at anodes of such electrowinning systems. In many zinc and copper electrowinning systems, a single electrolyte contacts both the anode and the cathode. This is possible because, in aqueous solutions, zinc and copper only have a single stable oxidation state (Cu2+ and Zn2+).

[0003] However, compared with zinc and copper, electrowinning of iron is more challenging, in part due to the fact that aqueous iron is stable in both Fe2+ (ferrous) and Fe3+ (ferric) ionic states. An electrochemical cell with a common (unseparated) electrolyte in contact with both anode and cathode will tend to experience a “shuttling” of ions in which ferrous ions are oxidized to ferric at the anode while ferric ions are reduced to ferrous at the cathode. The ferrous / ferric shuttle represents wasted energy as ions simply shuttle back and forth between the two aqueous oxidation states without achieving the desired reaction (e.g., electroplating metallic iron).

[0004] One way of mitigating the ferrous / ferric shuttle is to physically separate the anode-contacting electrolyte (“anolyte”) from the cathode-contacting electrolyte (“catholyte”) such that physical mixing of the electrolytes is prevented. However, provision may still be made for one or more ionic charge-carriers to pass through such a separation, such as via a salt-bridge, a semi-permeable membrane, an ion-exchange membrane, or other ion-conductive material or structure.

[0005] When the ionic conductive separator is a polymeric membrane (e.g., a porous membrane or an ion-selective membrane), it is desirable for the membrane to be consistently held at a desired physical distance from a reactive surface of the anode and / or cathode electrode. Variations in the distance between the separator and the electrode surface (e.g., across the membrane area or over time) can cause electrochemical inefficiencies which can impact the performance of the electrochemical system overall. Unfortunately, many separator membrane materials are quite flexible and prone to being displaced by differences in fluid pressures across the membrane, thereby causing inefficiencies or other problems with the performance of the electrochemical system.

[0006] Described herein are various devices, methods, systems, configurations, and / or processes for addressing the above-described challenges or other challenges as described or apparent to those skilled in the art of electrochemical systems.SUMMARY

[0007] In various aspects, the present disclosure provides processes, systems, methods, devices, and apparatus for configuring electrochemical electrode cartridges for effective separation of electrolytes while allowing for removal of electrode cartridges from an electrochemical cell for cell maintenance, repair or replacement of electrodes, or other operations.

[0008] Aspects disclosed herein include cartridge electrodes for use in electrochemical systems, a cartridge electrode comprising: a plurality of elongated electrode elements, each elongated electrode element comprising: a conductive structure; a tubular separator; a reaction space between the conductive structure and the separator; and a reaction surface within the reaction space; an in-flow manifold configured to direct a cartridge electrolyte through the reaction space of each of the elongated electrode elements; and an out-flow manifold configured to receive the cartridge electrolyte exiting each of the reaction spaces of the elongated electrode elements.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a schematic illustration of a prior art electrowinning bath comprising positively charged anodes and negatively charged cathodes.

[0010] FIG. 2 is a schematic illustration of an electrowinning bath with electrodes shown removed from the bath.

[0011] FIG. 3A is a schematic diagram showing a cross-sectional view of an example cartridge electrode.

[0012] FIG. 3B is a schematic diagram showing cross-sectional view of an example cartridge electrode showing deflection of a separator membrane.

[0013] FIG. 4 is a schematic diagram showing an electrochemical cell with a separator membrane held against an electrode by a difference in electrolyte pressure on opposite sides of the separator.

[0014] FIG. 5 is a schematic diagram showing an electrochemical system in which one electrolyte flows under the power of a suction pump.

[0015] FIG. 6 is a schematic diagram showing an electrochemical cell in which one electrolyte is maintained at a higher hydrostatic head (liquid surface level) than another electrolyte.

[0016] FIG. 7 is a schematic diagram showing a cartridge electrode comprising an array of elongated electrode elements.

[0017] FIG. 8 is a schematic perspective view diagram showing a cartridge electrode comprising an array of elongated electrode elements and a cover sheet.

[0018] FIG. 9 is a schematic diagram showing a cross section of a portion of an elongated electrode element (such as through line B-B of FIG. 7).

[0019] FIG. 10 is a schematic diagram showing a transverse cross section of an example flow diffusion coupling.

[0020] FIG. 11 is a schematic diagram showing a cartridge electrode comprising an array of elongated electrode elements and a pair of counter-electrodes positioned over an electrolyte bath.STATEMENTS REGARDING CHEMICAL COMPOUNDS AND NOMENCLATURE

[0021] In general, the terms and phrases used herein have their art-recognized meaning, which can be found by reference to standard texts, journal references and contexts known to those skilled in the art. The following definitions are provided to clarify their specific use in the context of this disclosure.

[0022] As used herein, the term “ionic conductivity” is used as conventionally understood in the field of electrochemistry and refers to a material property of permitting or encouraging transport of one or more ionic species through a material or component, the material or component being solid, fluid, or a combination thereof.

[0023] As used herein, the term “electronic conductivity” is used synonymously with “electric conductivity” and “electrical conductivity” (including all equivalent adverb forms) and refers to a material property of conducting electrons through a material or component, the material or component being solid, fluid, or a combination thereof.

[0024] As used herein, the term “reaction surface” (such as but not limited to reaction surface 306 or 904) refers to a material or component that facilitates one or more electrochemical reactions (such as but not limited to ion oxidation or ion reduction) on at least a portion of its surface, the reaction surface being at least partially provided between a conductive structure (such as but not limited to conductive structure 304 or 902) and a separator (such as but not limited to separator 308, 406, or 908). In various aspects, the reaction surface is at least partially in physical contact with the conductive structure and at least partially in physical contact with the separator. As an illustrative example, corresponding to some aspects described elsewhere herein, a reaction surface (such as but not limited to reaction surface 306) may be a cylindrical carbon felt or foam, which optionally has a concentric hollow middle portion containing a concentric cylindrical conductive structure (e.g., a metal rod or stem), with a separator (e.g., a film or sheet of an ion exchange material) surrounding (e.g., wrapped around) at least a portion of the reaction surface, where in some aspects the reaction surface is at least partially in physical contact with the conductive structure and concurrently at least partially in contact with the separator.

[0025] As used herein, the term “separator” is used as conventionally understood in the field of electrochemistry and refers to a structure for separating two or more electrochemical reactants (e.g., solid, liquid, and / or gaseous reactants) within an electrochemical cell. Separators generally take the form of a material layer configured to regulate, mitigate, or restrict transport of some chemical species from one region to another. In an electrochemical cell containing solid or fluid reactants, a separator generally separates two regions or volumes, such as one electrolyte (e.g., catholyte, midlyte, or anolyte) from another electrolyte (e.g., catholyte, midlyte, or anolyte), thereby regulating, mitigating, or restricting transport of molecules and / or ions from one electrolyte to the other. Separators may include electrically non-conductive (often polymeric) materials that are porous (including microporous and nanoporous).

[0026] Separators are often (though not necessarily) extruded or cast polymer sheets with a defined or specified range of porosity. Microporous and nanoporous separators generally have a very low water permeability while allowing some bi-directional transport of ionic species. In some cases, the term “membrane” may be synonymous with “separator,” unless either term is further specified (e.g., “ion exchange membrane”).

[0027] Separators may comprise polymers and / or ceramic materials, including porous materials, microporous materials, nanoporous materials, and ion exchange materials, among other possible material constituents. As used herein, the term “tubular separator” refers to a separator, as just described, at least partially having a tubular or cylindrical shape, form, or configuration. For example, a separator may be formed into a tubular separator by providing a sheet or film of a separator material wound or wrapped around a cylindrical structure.

[0028] As used herein, the terms “ion-selective membrane” and “ion exchange membrane” are used as conventionally understood in the field of electrochemistry and refer to a non-porous, semi-permeable membrane that selectively permits the transport of specific ions while substantially excluding others, based on their charge, size, or both. lon-exchange membranes may be polymer and / or ceramic materials. Ion exchange membranes may comprise fixed ionic groups-either cationic or anionic-that facilitate the movement of counter-ions (ions of opposite charge) through the membrane matrix, while repelling co-ions (ions of like charge). Ion exchange membranes may be classified as cation exchange membranes (CEMs), which allow the passage of cations, or anion exchange membranes (AEMs), which allow the passage of anions. The non-porous nature of the membrane ensures that ion transport occurs via diffusion through the polymer matrix rather than through physical pores.

[0029] As used herein, the term “ion exchange resin” refers to a bulk material (regardless of physical form-factor) with properties of conducting one or more ionic species while preventing or restricting conductivity of one or more other ionic species.

[0030] As used herein, the term “cation exchange membrane” is used as conventionally understood in the field of electrochemistry and refers to an ion-selective membrane that permits or encourages transport (ionic conductivity) of cations (positively charged ions) while restricting or preventing transport of anions (negatively charged ions).

[0031] As used herein, the term “proton exchange membrane” is used as conventionally understood in the field of electrochemistry and refers to an ion-selective membrane that permits or encourages transport of protons (and optionally other cations) while restricting or preventing conductivity of anions.

[0032] As used herein, the term “anion exchange membrane” is used as conventionally understood in the field of electrochemistry and refers to an ion-selective membrane that permits or encourages transport of negatively charged anions while restricting or preventing conductivity of protons and other cations.

[0033] As used herein, the term “electrolyte” refers to a liquid (including aqueous liquids, ionic liquids, and other non-aqueous liquids) containing free ions capable of diffusing through the liquid. In some cases, electrolytes may comprise gaseous components, including dissolved gasses, gas bubbles in liquid, and gas / liquid mixtures.

[0034] As used herein, the term “catholyte” is used as conventionally understood in the field of electrochemistry and refers to an electrolyte in contact with an electrochemical cathode.

[0035] As used herein, the term “anolyte” is used as conventionally understood in the field of electrochemistry and refers to an electrolyte in contact with an electrochemical anode.

[0036] As used herein, the term “active area” is used as conventionally understood in the field of electrochemistry and refers to an area of an electrochemical cell in which electrochemical reactions occur. The “active area” of an electrochemical cell may correspond to an area of an anode, an area of a cathode, an area of a separator, or combinations of these. An “active area” of an electrode (anode or cathode) may be less than a total area of the electrode if portions of the electrode are blocked by ionically non-conductive materials that prevent ions or other electrochemical reactants from reaching those portions of the electrode surface.

[0037] As used herein, the terms “anode chamber” and “cathode chamber” are used as conventionally understood in the field of electrochemistry and refer to regions of an electrochemical cell containing “anolytes” and “catholytes,” respectively. Anode and / or cathode “chambers” may be fluidically sealed from other regions of a cell, and may be configured to allow electrolyte to flow-through the chamber or to statically contain the electrolyte (or both, potentially at different times). Other terms such as “volume,”“reaction space,” or “compartment” may be used in place of the word “chamber.” As used herein, the terms “metal rich solution,”“metal rich electrolyte”“leachate,”“lixiviant” or other related terms may refer to a liquid suitable for use as a catholyte in a metal electrowinning cell.

[0038] As used herein, the term “electrical source” may refer to any source of electrical energy, including electrical generation equipment such as turbines (whether powered by steam, wind, water or otherwise), photovoltaic cells, electrical grids, batteries, power supplies, rectifiers, inverters, or any other source of electrical energy, or any combination of sources, including conversion equipment.

[0039] As used herein, the term “electrical load” refers to a device or combination of devices capable of receiving and consuming, storing, or transporting electrical energy.

[0040] The term “pore”, as used herein, refers to small and / or tortuous openings or paths extending from one face of a planar material to the opposite face of the material.

[0041] The term “porous”, as used herein, refers to a material or structure within which pores are present, organized and / or arranged in the material. Thus, for instance, in a porous material, the pores are volumes within the body of the material where there is no material (e.g. voids). Pores in a material are not intended to include the space occupied by atoms, ions and / or molecules of a material including monomers, oligomers and polymers, for example, of a barrier or separator. Porous materials and pores may be characterized by certain pore characteristics including, but not limited to, an average pore size, a maximum pore size, an O90 pore size, pore tortuosity, and others. A pore size generally refers to a cross sectional dimension such as diameter or cross-sectional width. Generally, as used herein, an average pore size refers to an empirically-derived numerical average of the diameter (or corresponding cross-sectional dimension) of each pore of the plurality of pores of a material or item.

[0042] The term porosity refers to a quantitative characteristic of a porous material or structure. In some embodiments, porosity is a measure of the void (i.e. “empty”) volume, such as pores, in a material. Porosity may be expressed as the fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. As used herein, a porous material has characteristics allowing transport of protons across it via the Grotthuss mechanism.

[0043] As used herein, a “microporous” material is characterized by an average pore size and / or an O90 pore size selected from the range of greater than 100 nm to less than or equal to 1 μm. As used herein, a “nanoporous” material is characterized by an average pore size and / or an O90 pore size selected from the range of 0.1 nm to less than 100 nm.

[0044] As used herein, “permeability” of aqueous dissolved ions refers to the capacity of a material, such as a porous material, to permit the passage of dissolved ionic species, in an aqueous solution, through its structure. lon permeability encompasses the transport of ions driven by concentration gradients, electrochemical potential, pressure differentials, or other forces. In the context of porous materials, ion transport may occur through interconnected pores, channels, or voids within the material, and may be influenced by factors such as pore size distribution, surface charge, tortuosity, and the physicochemical interactions between the ions and the pore surfaces. lon permeability is typically, but not necessarily, quantified by measuring the flux of specific ions across the material under defined conditions and may be expressed in units such as moles per square meter per second (mol / m2·s).

[0045] The term “iron electroplating” (or “iron plating” as used synonymously herein) refers to a process by which dissolved iron is electrochemically reduced to metallic iron on a cathodic surface. Equivalent terms “electrodeposition,”“electroforming,” and “electrowinning” are also used herein synonymously with “iron electroplating.” The shape or form-factor of the electroplated iron need not be a “plate” by any definition of that term. For example, electroplated iron may take any shape or form and may be deposited on any suitable cathodic surface as described in various embodiments herein. Examples of possible physical forms of “electroplated” iron include chips, flakes, coins, crowns, powder, strips, or other shapes. In some embodiments, a cathodic surface material may be selected for a degree to which deposited iron adheres to the cathodic surface. For example, if a desired electroplated product is a powder, a cathodic surface with a low iron adhesion may be desired. Examples of materials with high and low iron adhesion properties are described herein, and additional examples will be clear to those skilled in the art. In various embodiments, some regions of a cathode may be masked prior to electroplating for producing electroplated material in a desired shape or form-factor, for example as described in U.S. Pat. No. 4,139,430, which is incorporated herein by reference to the extent not inconsistent herewith.

[0046] As used herein, electrochemically generated ions, such as electrochemically generated protons and electrochemically generated iron ions (e.g., Fe2+, Fe3+), refer to ions that are generated or produced in an electrochemical reaction. For example, electrochemical oxidation of water at an anode may electrochemically generate protons and electrochemically generate oxygen. For example, aqueous ferrous (Fe2+) ions in an anolyte may be electrochemically oxidized an anode to aqueous ferric (Fe3+) ions. As used herein, the term “anodically generated” ions refers to ions generated by electrochemically oxidation at an anode. As used herein, the term “anodically generated” ions refers to ions generated by electrochemically reduction at a cathode.

[0047] As used herein, aqueous protons and electrochemically generated protons are intended to be inclusive of aqueous protons and aqueous hydronium ions.

[0048] The term “dissolved” in reference to ions, such as dissolved ferric ions or dissolved ferrous ions, refers to ions dissolved and thereby solvated by a solvent such as water or an aqueous solution. As used herein, the term “aqueous ions”, such as aqueous ferric ions or aqueous ferrous ions, refers to ions dissolved in water. The term “non-dissolved” refers to a solid undissolved non-solvated species. The term “non-dissolved ferric” and “solid ferric” refer to any one or more solid compositions or materials in which ferric (Fe3+ or Fe(III)) exists in a non-dissolved solid, such as, for example, ferric in solid particles or pieces of hematite. As an illustrative example, reduction of solid hematite to solid magnetite comprises the reduction of non-dissolved (solid) ferric to non-dissolved (solid) ferrous. The term “non-dissolved ferrous” and “solid ferrous” refer to any one or more solid compositions or materials in which ferrous (Fe2+ or Fe(II)) exists in a non-dissolved solid, such as, for example, ferrous in solid particles or pieces of magnetite or wüstite. Likewise, the term “solid ions”, such as “solid iron ions”, refers to ions bound in a solid and undissolved composition.

[0049] As used herein, the term “material” is inclusive of pure materials and mixtures of a plurality of different materials or species.

[0050] As used herein, the term “wt. %” or “wt %” refers to a weight percent, or a mass fraction represented as a percentage by mass. The term “at. %” or “at %” refers to an atomic percent, or an atomic ratio represented as a percentage of a type of atom with respect to total atoms in a given matter, such as a molecule, compound, material, nanoparticle, polymer, dispersion, etc. The term “mol. %” refers to molar percent or percent by moles. The term “vol. %” refers to volume percent.

[0051] The term “predominantly” is used herein to refer to a property, condition, or value being greater than 50%. In specific instances, the term “predominantly” may indicate a property, condition, or value being greater than 60%, greater than 70%, greater than 80%, greater than 90%, greater than 95%, greater than 98%, greater than 99%, greater than 99.5%. For example, a material mixture characterized as “predominantly wüstite” is more than 50 mol. % wüstite, or in other instances at least 60 mol. % wüstite, at least 70 mol. % wüstite, at least 80 mol. % wüstite, at least 90 mol. % wüstite, at least 95 mol. % wüstite, at least 98 mol. % wüstite, at least 99 mol. % wüstite, at least 99.5 mol. % wüstite, with the balance being other compositions, such as but not limited to hematite, magnetite, iron metal, and / or impurities.

[0052] The terms “substantially” and “approximately” are used interchangeably and refer to a property, condition, or value that is equivalent to or is within a reasonable variance from a stated property, condition, or value. For example, a property, condition, or value described as “substantially” or “approximately” X (X being a number for purpose of this paragraph), may include properties, conditions, or values that are within 20%, within 10%, within 5%, within 1%, or within 0.1% of said X. Examples of such uses include phrases such as “substantially equal”, “substantially equivalent”, “substantially unchanged”, “approximately”, and “approximately equal to.”

[0053] As used herein, the term “and / or” is used herein, in the description and in the claims, to refer to a single element alone or any combination of elements from the list in which the term and / or appears. In other words, a listing of two or more elements having the term “and / or” is intended to cover embodiments having any of the individual elements alone or having any combination of the listed elements. For example, the phrase “element A and / or element B” is intended to cover embodiments having element A alone, having element B alone, or having both elements A and B taken together. For example, the phrase “element A, element B, and / or element C” is intended to cover embodiments having element A alone, having element B alone, having element C alone, having elements A and B taken together, having elements A and C taken together, having elements B and C taken together, or having elements A, B, and C taken together.

[0054] As used herein, the term “+” refers to an inclusive range of values, such that “X+Y,” wherein each of X and Y is independently a number, refers to an inclusive range of values selected from the range of X−Y to X+Y. In the cases of “X+Y” wherein Y is a percentage (e.g., 1.0±20%), the inclusive range of values is selected from the range of X−Z to X+Z, wherein Z is equal to X·(Y / 100). For example, 1.0±20% refers to the inclusive range of values selected from the range of 0.8 to 1.2.DETAILED DESCRIPTION

[0055] In the following description, numerous specific details of devices, device components and methods are set forth to provide a thorough explanation of the precise nature of the various inventions described herein. It will be apparent, however, to those of skill in the art that the various inventions can be practiced without these specific details. Without wishing to be bound by any particular theory, there may be discussion herein of beliefs or understandings of underlying principles relating to the devices and methods disclosed herein. It is recognized that regardless of the ultimate correctness of any mechanistic explanation or hypothesis, an embodiment of devices and methods may nonetheless be operative and useful.

[0056] Applicant has previously described systems and methods for electrowinning of metallic iron from iron-containing feedstocks such as iron-containing ores and waste materials as described for example in U.S. Pat. No. 11,767,604 (“the '604 patent”), which is incorporated herein by reference and attached as Appendix A. Some examples described in the '604 patent include subsystems or electrochemical cells referred to therein as “Acid Regeneration” (“AR cells”) cells or subsystems configured to reduce “ferric” (Fe3+) ions to “ferrous” (Fe2+) ions, and to regenerate acid (H+) consumed during leaching of the feedstock material(s). The '604 patent also describes various examples of “plating” cells configured to cathodically reduce iron ions to metallic iron which may be removed and recovered as a product. Some plating cells described in the '604 patent are configured to anodically oxidize ferrous ions to ferric ions while electroplating iron at the cathodes. Some plating cells described in the '604 patent are configured to anodically split water in order to evolve oxygen at the anodes while electroplating iron at the cathodes. The “cartridge” electrode configurations described herein may be configured for use in any of the plating cells and / or acid regeneration cells described n the '604 patent.

[0057] FIG. 1 (only) illustrates a prior art example electrowinning bath 100 containing a metal rich electrolyte 110 into which anodes A and cathodes C may be submerged.

[0058] FIG. 1 illustrates four anodes A and three cathodes C for simplicity of description, but any number of anodes and cathodes may be combined into a single bath. If both faces of each cathode are to be deposited with metal, the number of anodes will be one greater than the number of cathodes. The anodes A may be electrically connected to a positive polarity (+) of a power supply (not shown). Similarly, the cathodes C may be electrically connected to a negative polarity of the power supply. Anodes and cathodes are conventionally connected to the power supply by contacting a corresponding electrical contact along an edge of the bath 100 or other structures similarly situated.

[0059] The cathode-contacting electrolyte 110 (“catholyte”), often referred to as an enriched solution, a leachate, or a lixiviant, typically contains one or more dissolved metal species to be extracted by electrodeposition at the cathodes C while a charge-balancing oxidation reaction (or combination of reactions) occurs at the anodes A, typically under an applied electrical current. The electrolyte 110 generally flows into, through, and out of the bath 100 so as to continually replenish the dissolved metal in the bath 100 as it is deposited on the cathodes.

[0060] In some electrowinning systems, the anode-contacting electrolyte (“anolyte”) may be the same fluid as the cathode-contacting electrolyte, as shown for example in FIG. 1. In such cases, both anodes and cathodes are in contact with the common electrolyte and any dissolved ionic constituents or any undissolved (e.g., colloidal) solids carried in the electrolyte. In many cases, the expected dissolved and undissolved materials do not adversely affect the electrochemical reactions or the effects are acceptable within those systems.

[0061] However, in other systems it is desirable to use separate fluids for anolyte and catholyte, allowing for anodic and cathodic reactions while preventing bulk mixing of the separate electrolytes. In such systems, it is desirable to maintain separation of the anolyte and catholyte streams while flowing both through respective anode and cathode fluidic channels. Maintaining this separation calls for separate anolyte and catholyte conduits separately directing anolyte and catholyte into their respective reaction spaces (e.g., “anode chamber(s)” and “cathode chambers” or “plating baths”). In addition, a barrier may be used to separate the fluids while providing for electrochemical interactions by allowing transport of charge-balancing ions through the barrier. In such separated electrolyte systems, a separator (which may be a membrane) may be used as such a barrier.

[0062] In the field of electrochemical systems, and particularly in the field of electrowinning metals, electrochemical cells may be configured with anodes and / or cathodes that are easily removable from an electrochemical cell 200, as shown for example in FIG. 2. Removal may be facilitated by suspending anodes 210 and / or cathodes 212 from support bars 216 which extend over structures of the electrolyte 222 in the bath 220. In some embodiments, the support bars 216 may also provide electrical connections at which positive and negative electrical connections can be made between the electrodes and respective contacts and power supply. In some cases, a support bar (or a component thereof) may be referred to as a “bus bar” to indicate a role in electrical connections. In some embodiments, support bars and electrical bus bars may be integrated into a single structure.

[0063] Alternatively, support bar 216 structures and electrical bus bar structures 216 may be provided as separate components, which may be made of different materials optimized for mechanical strength and electrical conductivity, respectively. For example, support bars may be made of steel or composite materials with substantial mechanical strength, but relatively low electrical conductivity; while electrical bus bars may be made of copper or other materials with higher electrical conductivity but lower mechanical strength. Some examples are described below with reference to FIG. 7.

[0064] In some electrowinning systems, cathodes 212 are removed once a desired quantity of metal has been electroplated onto the surface. The electrowon metal may then be removed from the cathodes so that the cathodes may be returned to the bath 220 for a subsequent electroplating operation. Similarly, anodes 210 may be removable from the bath 220 for anode maintenance, anode replacement, bath maintenance, etc.

[0065] In the example of FIG. 2, the cathodes 216 may be submerged directly in a catholyte solution 222. However, maintaining separate electrolytes with removable anodes involves separate fluidic connections for a separate anolyte to flow through the anode electrodes 210 without mixing with the catholyte 222. To address this, various features and examples are provided herein for “cartridge” electrodes that contain flow-directing structures for flowing an electrolyte into, through, and out of the cartridge to facilitate the desired electrochemical reactions. In various implementations, such flow-through cartridge electrodes may be used as either anode or cathode, or both. Various features and examples of flow through cartridge electrodes are shown and described herein.

[0066] FIG. 3A is a cross-sectional illustration of an example cartridge electrode 300 (e.g., an anode in the configuration of FIG. 2 or a cathode in some other configurations) positioned between a pair of counter-electrodes 302 (e.g., cathodes in the configuration of FIG. 2 or anodes in some other configurations). The illustrated cartridge electrode 300 comprises a conductive structure 304, a reaction surface 306, and a separator 308. In the example of FIG. 3A, fluidic conduits 310 are provided as holes or conduits through or adjacent to the conductive structure 304 and the support structure 316.

[0067] The conductive structure 304 is generally configured to serve as a “current collector” for conducting electrical current between a reaction surface and an electrical source or load. The conductive structure 304 may comprise a metallic or non-metallic electrically conductive material of any form-factor and dimensions suitable for conducting electrons to or from a reaction surface 306. For example, the conductive structure 304 may comprise a metal such as copper, steel, stainless steel, titanium, other metals, a non-metal such as carbon or graphite, or any combination(s) of these.

[0068] The conductive structure 304 may comprise a single material or may be a composite, alloy, and / or assembly of multiple materials. In some embodiments, the conductive structure 304 comprises an electrically conductive material in the form of a solid rod or bar, a hollow tube, or a porous mesh, foam, felt, other porous conductive structure, or any combination(s) of these.

[0069] In various embodiments, the conductive structure may have any shape or configuration as needed for a particular application. For example, the conductive structure 304 may be planar as shown in FIG. 2 or FIG. 6, elongated as described below with reference to FIG. 7-FIG. 11, rod-shaped, bar-shaped, plate-shaped, or any combination of shapes and / or configurations.

[0070] In various embodiments, the reaction surface 306 may comprise a coating or layer of material in electrically conductive contact with the conductive structure 304 and having a surface suitable for promoting desired reactions. In some embodiments, the reaction surface 306 may be porous and / or featured to allow an electrolyte to flow over or through the reaction surface 306. The reaction surface 306 may comprise one or more additional material(s) that is bonded, welded, adhered, compressed, pressed, welded, crimped, or otherwise held in conductive contact with the conductive structure 304. In some embodiments, the reaction surface 306 may comprise one or more layers or elements of material and / or surface treatment. For example, a reaction surface may comprise a gas diffusion layer and a catalyst material. In some embodiments, the reaction surface 306 may include a layer of felt, foam, woven or unwoven fibers, felted fibers, wools, or other structures made of carbon or graphite in electrically conductive contact with the conductive structure 304.

[0071] According to various aspects, a reaction surface, such as but not limited to reaction surface 306, may be configured to maintain physical contact with the separator, such as but not limited to separator 308, during operation of the cartridge electrode even if and when the separator undergoes expansion or contraction. There are several non-limiting example configurations that facilitate the reaction surface maintaining contact with an expanding and / or contracting separator. In some aspects, for example, the cartridge electrode is assembled with the reaction surface having a constricted diameter that is less than its relaxed diameter, such that the reaction surface may expand as the separator expands during operation of the cartridge electrode. In various aspects, at least a portion of the reaction surface is configured to expand (or contract) as the separator expands (or contracts) to maintain at least partial physical contact between the reaction surface and the separator. In some aspects, for example, the reaction surface is configured to comprise fibers extending generally away from a cylinder axis of the conductive structure (e.g., approximately 10° C. to 90° C. off the cylinder axis, e.g., perpendicular thereto) where said fibers are constricted by the separator so as to expand with / against the separator if and when the separator itself expands or otherwise stretches away from the conductive structure. For example, in some aspects, reaction surface comprises fibers that undergo a change from a bent configuration to a less bent (or more straight) configuration if and when the separator expands or stretches away from the conductive structure, thereby the fibers maintaining physical contact with said separator. For example, in some aspects, reaction surface comprises fibers that undergo a change from a small angle between an axis of each fiber and a cylinder axis of the conductive structure to said angle increasing if and when the separator expands or stretches away from the conductive structure, thereby the fibers maintaining physical contact with said separator. For example, in some aspects, the conductive structure and the reaction surface may be configured as a brush with an electrical conductive central cylindrical stem forming the conductive structure and the brush fibers forming the reaction surface. In various aspects, said fibers are formed of any one or combination of materials as any reaction surface described herein. For example, in various aspects herein, said fibers are formed of one or more carbon allotropes. For example, in various aspects herein, said fibers are carbon fibers or are formed of carbon fibers.

[0072] Alternatively or in addition, the reaction surface 306 may comprise a surface treatment applied to the conductive structure 304, such as machining, knurling, channeling, etc. Such treatments may be applied for the purpose of increasing a reaction surface area, improving adhesion of a separate reaction surface layer, providing flow fields for directing flow of an electrolyte or other reactant, or others.

[0073] In some embodiments, a cartridge electrode may include a flow field comprising one or more structures configured to direct electrolyte flow along a desired path through or adjacent to the reaction surface. In some embodiments, a flow field (if present) may comprise grooves, channels, conduits, or other structures formed into one or more of the conductive structure 304, the reaction surface 306, and / or the separator 308. Alternatively, a flow field (if present) may comprise an additional structure interposed between a conductive structure 304 and a reaction surface 306 or between a reaction surface 306 and the separator 308.

[0074] The separator 308 may generally comprise an electrically non-conductive material suitable for preventing mixing of separate electrolytes while allowing transfer of charge-carrying ionic species. Example separator membranes may include porous membranes allowing for bi-directional migration of charged ions driven by electromotive force of the positively charged anode and the negatively charged cathode. Porous membranes may include woven or non-woven polymeric, ceramic, or other non-conductive materials with micro-scale or nano-scale pores. Alternatively, some separator membranes, referred to as ion-selective membranes (or ion-exchange membranes, IEMs), are configured to selectively allow and / or impede migration of specific ions such as anion exchange membranes, or “AEMs” configured to allow transport of anions while inhibiting or preventing transport of cations. Cation exchange membranes, or “CEMs” and proton exchange membranes (PEMs) are generally configured to allow transport of cations and / or protons while preventing or inhibiting transport of anions.

[0075] A separator useful in aspects herein, such as but not limited to separator 308, separator 406, and / or separator 908, can be a homogeneous material made up of a single polymer or ceramic material or the separator can be a heterogeneous material made up of a plurality of materials such as a plurality of polymers, a plurality of ceramic materials, or a combination of one or more polymers and one or more ceramic materials. For example, in some cases, a heterogeneous membrane may comprise a thermoplastic polymeric support structure embedded with particles or strands of one or more ion exchange materials. In a heterogeneous material separator, the support structure may be substantially impermeable to ionic transport while the ion exchange resin provides pathways for the transport of anions or cations through the membrane.

[0076] By contrast a homogeneous membrane may comprise a single polymer providing both mechanical and ion transport properties. A separator useful in aspects herein, such as but not limited to separator 308, separator 406, and / or separator 908, may comprise a single layer or multiple layers of homogeneous or heterogeneous material(s). A separator useful in aspects herein, such as but not limited to separator 308, separator 406, and / or separator 908, may be configured in a flat sheet, tube, or other form factor as suitable for a particular cartridge electrode configuration.

[0077] FIG. 3A schematically illustrates (in a cross-sectional view) some features of a flow-through cartridge electrode 300. The flow-through electrode and a pair of counter-electrodes are shown submerged in a bath 312 containing an electrolyte 314. The cartridge electrode 300 and the cartridge electrolyte (within flow channels 310) is separated from the counter-electrodes 302 and the bath electrolyte 314 by a separator 308 adjacent to the reaction surface 306 and conductive structure 304. The illustrated flow path of a flow-through electrolyte 310 is merely schematic and is not intended to limit the scope of possible embodiments. In some embodiments the flow-through electrolyte flows through the space between the conductive element 304 and the separator 308.

[0078] The illustrated flow-through cartridge electrode 300 includes flow channels 310 for directing anolyte into, through, and out of the cartridge electrode chamber 300 to replenish anodic reactants during operation of the electrochemical cell. In the example shown in FIG. 3A, electrolyte may flow into a supply channel 310, then into a reaction space 307 between a separator membrane 308 and a conductive structure 304 and / or reaction surface 306. While the arrows shown in FIG. 3A suggest a particular flow path, any other flow paths or configurations may be employed to direct electrolyte into, through, and out of a reaction chamber within the flow-through cartridge electrode 300.

[0079] In many electrochemical systems, maintaining a separator membrane at a consistent distance to both electrode surfaces across the “active area” (as defined above) is desirable to achieve efficient and consistent electrochemical reactions, which is achieved in various aspects herein. For example, FIG. 3A illustrates a preferred position, according to various aspects herein, of a separator membrane 308 as electrolyte flows through a space between the conductive structure 304 and the separator 308, wherein the separator 308 is consistently spaced from the conductive structure 304 across the area of the interface between the two.

[0080] Many IEM polymers and ceramics lack sufficient mechanical strength, tensile strength, and creep resistance to withstand substantial fluid pressures exerted by electrolytes flowing in an electrowinning cell without deformation or tearing. In general, as the active area of an electrochemical cell increases, so does the distance between membrane attachments (e.g., the edges of a sheet) and a central portion of the membrane sheet. A membrane may generally be supported at peripheral edges so as to allow the entire membrane area to be available for ionic transport.

[0081] As shown in the two-dimensional cross-sectional view of FIG. 3B, a separator membrane 308 supported at its peripheral edges 320 may tend to “balloon” outwards away from a conductive structure 304 and / or a reaction surface 306 (and / or towards a counter-electrode 302) as a result of fluid pressures in the electrolyte space 307 between the conductive structure 304 and the membrane 308. Movement of the membrane may also be caused by local weakness, local temperature variations, or un-controlled variations in flow. Some of these challenges can cause feedback loops creating weakened membrane sections or even perforations.

[0082] Various approaches can be taken to mitigate these challenges, but some have undesirable drawbacks. For example, support structures may be positioned on one or both sides of a separator membrane in order to mechanically support a central section of the membrane. However, those support structures tend to add distance between anode and cathode, resulting in increased electrical resistance, increased voltage, and decreased energy efficiency of the electrochemical cell. Membrane support structures will also tend to block some regions of the separator membrane, leaving those regions unable to participate in the desired electrochemical reactions.

[0083] With reference to FIG. 4, another configuration for supporting a separator is to establish and maintain a pressure difference across the separator in order to press the separator onto one of the electrode faces, thereby ensuring consistent positioning of the membrane. FIG. 4 illustrates an example electrochemical cell 400 (e.g., an electrowinning cell or an acid regeneration cell), comprising a cell container 410 in which a first electrode 402 is positioned within a first chamber 412 containing a first electrolyte 416. A separator membrane 406 separates the first chamber 412 from a second chamber 414, which contains a second electrolyte 418 and a second electrode 404. A first electrolyte 416 on the first-electrode-side of the separator 406 may be held at a first pressure that is greater than a second pressure of a second electrolyte 418 on the second-electrode-side of the separator 406. This pressure difference will tend to deflect the separator 406 towards the second electrode 404. In the illustrated example, the second electrode 404 may comprise a plurality of recesses 408 providing a space for electrolyte between the electrode 404 and the separator 406. The recesses 408 may comprise longitudinal channels or other spaces between structures of the electrode 404 (which may include one or more conductive structures and / or one or more reaction surfaces as described above). For example, the electrode 404 may comprise a (woven or non-woven) mesh, a corrugated sheet, a channeled sheet, a perforated sheet, a felt, or other structures allowing flow of electrolyte through and / or around structures of the electrode 404.

[0084] In some embodiments, the configuration of FIG. 4 may be implemented in an electroplating bath such as that described above with reference to FIG. 2, in which case, the first electrode 402 may be an electrolytic anode (e.g., for performing a water-splitting oxygen evolution reaction (OER) or another oxidation reaction such as oxidation of Fe2+ ions to Fe3+ ions) and the second electrode 404 may be an electrolytic cathode for performing reduction of one or more metal cations to form a metallic deposit (e.g., iron, zinc, copper, cobalt, nickel, etc.) on the second electrode. In other embodiments, the first electrode may be an electrolytic cathode, and the second electrode 404 may be an electrolytic anode. In still other electrochemical cell configurations, the first electrode 402 may be a galvanic cathode and the second electrode 404 may be a galvanic anode. Or the first electrode 402 may be a galvanic anode and the second electrode 404 may be a galvanic cathode.

[0085] In various embodiments, a pressure difference between electrolytes may be selected to be sufficient to retain the separator in a desired position relative to one or both electrodes. Therefore, in many cases, an excess pressure on a high-pressure side of a separator should be at least as great as an expected pressure variation of electrolyte on the low-pressure side. For example, a high-pressure side electrolyte may be maintained at a pressure of at least 0.05 bar to 1 bar greater than an anticipated variation in pressure on the low-pressure side. In some embodiments, a hydraulic pressure of a low-pressure side electrolyte may be monitored and pressure of the high-pressure electrolyte may be adjusted in response to such monitoring in order to maintain a pressure difference of 0.01 bar to 1 bar or more. In other embodiments, a high-pressure side hydraulic pressure may be established at a consistent pressure selected to be at least 0.1 to 1 bar or more greater than a maximum hydraulic pressure expected on the low-pressure side.

[0086] Various methods and systems may be used to establish and maintain a pressure difference as described above with reference to FIG. 4. For example, in some embodiments, a suction pump may be used to apply a negative pressure to the second electrolyte 418 as it is drawn out of the second electrode chamber 414. Any suitable suction pump type may be used, such as centrifugal pumps, submersible pumps, jet pumps, diaphragm pumps, positive displacement pumps, or others.

[0087] FIG. 5 is a schematic illustration of an electrochemical system 500 comprising a suction pump 502 positioned downstream of an outlet from second electrode chambers 512 of a group of electrodes within an electrochemical system 500. The first electrolyte 520 may be driven through the electrochemical system 500 by any suitable pump 504 or gravity-driven flow system. The second electrolyte 522 may be drawn out of the second electrode chambers 512 at a sufficiently low pressure relative to the first electrolyte 520.

[0088] For example, the electrochemical system 500 of FIG. 5 may be configured as an electroplating bath (such as that shown in FIG. 2) in which the lower pressure electrolyte 522 is the anode electrolyte (anolyte) which is drawn out of the anodes 512 by a suction pump 502 while the higher-pressure cathode electrolyte (catholyte) 520 may be pumped through the plating bath by any suitable pump 504, provided that the anolyte is maintained at a lower pressure than the catholyte.

[0089] In an alternative configuration, the system 500 of FIG. 5 may be arranged as an acid regeneration cell stack in either a monopolar or bipolar configuration. In such embodiments, the lower-pressure electrolyte 512 is the cathode electrolyte (catholyte), which may be withdrawn from the cathode chambers 512 by a suction pump 502. In such embodiments, the higher-pressure electrolyte 520 is the anode electrolyte (anolyte), which may be pumped through the anode chamber 510 by any suitable pump 504 or gravity driven flow system. In some embodiments, the pressure of the higher-pressure electrolyte may vary and the suction pump may be configured to maintain a lower pressure than the lowest variance of the higher-pressure electrolyte. Alternatively, the vacuum pump may be controlled in response to a measured pressure of the higher-pressure electrolyte such that at least the desired pressure difference is maintained.

[0090] In some embodiments, an electrolyte pressure difference may be maintained by maintaining a difference in hydrostatic head height between electrolytes on opposite sides of the separator. FIG. 6 schematically illustrates an electrochemical cell 600 in which a first electrolyte 602 in a bath 604 surrounds a flow-through cartridge electrode 610 through which a second electrolyte flows from a cartridge inlet 612 to a cartridge outlet 614. The first electrolyte 602 in the bath 604 may flow into the bath via an inlet 616 and out of the bath via corresponding outlet at an opposite end of the bath (e.g., in line with the inlet 616). The bath electrolyte surface level 620 may be maintained by controlling a rate of flow of the first electrolyte into and out of the bath. As shown in FIG. 6, the bath electrolyte surface level 620 may be maintained at a level above both the second electrolyte inlet 612 and the second electrolyte outlet 614.

[0091] The cartridge electrode of FIG. 6 is supported by support bar 624, electrolyte flows from the inlet 612, into the vertical downcomer 630, then through the bottom manifold 632, which directs the electrolyte up through the active area of the electrode 610 and then out of the cartridge electrode through the outlet conduit 615 to the bath outlet 614.

[0092] Another approach to consistently maintaining a separator within a desired distance to an electrode is to use a separator membrane in the shape of a tube. This takes advantage of the “hoop stress” of a circular tube, meaning the pressure within a section of a circular tube should exert a consistent stress across the circumference of the tube. This approach takes maximum advantage of a membrane material's inherent strength. In some embodiments, a cartridge electrode comprises an array of elongated electrode elements, each comprising a conductive structure, a reaction surface, and a tubular membrane.

[0093] FIG. 7, FIG. 8, and FIG. 11 illustrate examples of a cartridge electrode 700 comprising an array of elongated elements 702. Each elongated element 702 includes a conductive structure, a reaction surface, and a membrane as described above. In a cylindrical elongated element configuration, the conductive structure, reaction surface, and membrane may be arranged concentrically with one another. Each elongated element is generally shown extending vertically between an upper support bar 710, an upper manifold 712 and a lower manifold 714. The support bar 710 is also shown with an electrical bus bar section 711 and electrical connections 715 to each elongated electrode element 702. In some aspects, the lower manifold may be an in-flow manifold configured to provide and direct an electrolyte through the reaction space of each of the elongated electrode elements and the upper manifold may be an out-flow manifold configured to receive the electrolyte exiting each of the reaction spaces of the elongated electrode elements. In some aspects, the upper manifold may be an in-flow manifold configured to provide and direct an electrolyte through the reaction space of each of the elongated electrode elements and the lower manifold may be an out-flow manifold configured to receive the electrolyte exiting each of the reaction spaces of the elongated electrode elements.

[0094] With reference to FIG. 7, in some embodiments, an electrolyte may be directed into an inlet port 722, downward through a first vertical conduit 724, through a lower manifold 714 configured to distribute electrolyte to the electrode elements 702, then up to the upper manifold 712 and out through an outlet port 726. In some embodiments, electrolyte may be driven down through two (or more) vertical conduits 724, 725. In some embodiments, electrolyte may be driven into the bottom manifold 714, up through the electrode elements 702, and out through an upper outlet 726.

[0095] In general, only the elongated electrode elements 702 need be electrochemically active and therefore electrically polarized by electrical connection to an electrical load or source. Structures of a cartridge electrode 700 that need not be electrochemically active, such as manifolds 712, 714, vertical conduits 724, 725, inlet and outlet ports 722, 726, and other similar structures, may be made of one or more non-conductive material such as polymeric materials. Polymeric materials suitable for acidic electrolytes may include polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), polyvinyl fluoride (PVF), acetal, ethylene chlorotrifluoroethylene (ECTFE), polyamide-imide (PAI), polyphenylene sulfide (PPS), high-density polyethylene (HDPE), ethylene chlorotrifluoroethylene (ECTFE), or others. If an alkaline electrolyte is to be used, suitable polymeric materials may include polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), polyvinyl fluoride (PVF), acetal, ethylene chlorotrifluoroethylene (ECTFE), polyamide-imide (PAI), polyphenylene sulfide (PPS), polysulfone (PSU), polyphenylsulfone (PPSF or PPSU), or others.

[0096] FIG. 9 and FIG. 10 illustrate components of some embodiments of elongated elements 702. FIG. 9 is a cross-sectional view of an example elongated element segment 702. The elongated element 702 comprises a central conductive structure 902 surrounded by a reaction surface 904, which is in turn surrounded by a separator 908.

[0097] In some embodiments, the central conductive structure 902 comprises a solid rod of one or more electrically conductive materials such as metals (e.g., iron, steel, stainless steel, titanium, magnesium or others), carbon, graphite, graphene, or other electrically conductive non-metal. The conductive structure 902 may be cylindrical, although non-cylindrical shapes (e.g., square, pentagonal, hexagonal, heptagonal, octagonal, etc.) may also be used. In some embodiments, the conductive structure 902 may have a hollow center and / or a central core of a different material than an outer portion of the conductive structure 902.

[0098] The reaction surface 904 is advantageously an electrically conductive and porous material through which electrolyte may flow along the length of the elongated element 702. Example reaction surface materials may include one or more conductive materials in a felt, foam, mesh, fabric, wool, and / or other porous form-factor. In some embodiments, the reaction surface may comprise a stack of discs slid over the conductive structure 902. In some embodiments, the reaction surface 904 may comprise a sheet of material wrapped around the conductive structure 902. In some embodiments, the reaction surface 904 may comprise one or more strips of material wrapped around a mandrel or the conductive structure 902 in a spiral pattern. In some embodiments, the reaction surface 904 may be sprayed or dip-coated onto the conductive structure 902.

[0099] In some embodiments, a reaction surface 904 material may be secured to the conductive structure 902 in a manner that permits electrical conductivity between the conductive structure 902 and the reaction surface 904. For example, the reaction surface 904 material may be adhered to the conductive structure 902 with a conductive adhesive such as a conductive epoxy, resin, silicone, or others. In some embodiments, the reaction surface 904 material may be soldered, brazed, or welded to the conductive structure 902. In other embodiments, the reaction surface 904 material may simply be connected to the conductive structure by a compressive force. In some embodiments, the reaction surface material may be mechanically attached to the conductive structure 902 such as by being pinched into channels or other constrictions in the conductive structure 902 or in additional structures (e.g., collars or sleeves) conductively secured to the conductive structure 902.

[0100] The separator 908 may generally comprise an electrically non-conductive material suitable for preventing mixing of separate electrolytes while allowing transfer of charge-carrying ionic species. Example separator membranes may include porous membranes allowing for bi-directional migration of charged ions driven by electromotive force of the positively charged anode and the negatively charged cathode. Porous membranes may include woven or non-woven polymeric, ceramic, or other non-conductive materials with micro-scale or nano-scale pores. Alternatively, some separator membranes, referred to as ion-selective membranes (or ion-exchange membranes, IEMs), are configured to selectively allow and / or impede migration of specific ions such as anion exchange membranes, or “AEMs” configured to allow transport of anions while inhibiting or preventing transport of cations. Cation exchange membranes, or “CEMs” and proton exchange membranes (PEMs) are generally configured to allow transport of cations and / or protons while preventing or inhibiting transport of anions.

[0101] The separator 908 can be a homogeneous material made up of a single polymer or ceramic material, or a heterogeneous material made up of multiple polymers and / or ceramic materials. For example, in some cases, a heterogeneous membrane may comprise a thermoplastic polymeric support structure embedded with particles or strands of one or more ion exchange materials. In such a heterogeneous structure, the support structure may be substantially impermeable to ionic transport while the ion exchange resin provides pathways for the transport of anions or cations through the membrane. By contrast a homogeneous membrane may comprise a single polymer providing both mechanical and ion transport properties. The separator 908 may comprise a single layer or multiple layers of homogeneous or heterogeneous material. The separator 908 may be configured in a flat sheet, tube, or other form factor as suitable for a particular cartridge electrode configuration. In some embodiments, a separator may comprise multiple layers, such as a mechanical support layer with high tensile strength and high porosity, and an ion-exchange layer with low tensile strength but high conductivity to ionic transport.

[0102] In various embodiments, a separator membrane 908 may be provided in a cylindrical form-factor and may be in physical contact with the reaction surface 904 along a substantial portion of the separator membrane 908. In some embodiments, a cylindrical separator membrane may be made by spiral-winding a strip of separator material on a mandrel, and adhering overlapping sections of the membrane together. Depending on the material(s) of the membrane, the overlapping sections may be adhered by thermal welding, ultrasonic welding, solvent bonding, adhesives, additive welding, or other processes.

[0103] Cylindrical separator membranes may also be made by wrapping elongated strips of membrane material into tubes and forming linear seams parallel to the longitudinal axis of the strip. Such a linear seam may be secured by thermal welding, ultrasonic welding, solvent bonding, adhesives, additive welding, or other processes. Cylindrical separator membranes may also be made by extruding a membrane material as a continuous cylinder which may be cut to a desired length.

[0104] FIG. 9 also shows a flow diffusion fitting 910 at one end of the elongated element 702. The flow diffusion fitting 910 is configured to seal the separator 908 to electrolyte conduits connected to the upper and lower manifolds 712, 714 (FIG. 7), thereby sealing the reaction spaces inside the separators 908. The upper flow diffusion fittings 910 may generally include structures for allowing fluid to flow through the fitting 910 while providing electrical connection from connectors 715 (FIG. 7) to the conductive elements 902 within the elongated electrode elements 702.

[0105] FIG. 10 illustrates an example flow diffuser fitting 910 comprising a central conductor 150, a peripheral attachment ring 152, and flow diffusion channels 154 configured to direct electrolyte into the reaction space between the conductive elements and the separators of an elongated electrode element 702.

[0106] In a cartridge electrode such as that shown in FIG. 7-FIG. 9, electrolyte may flow from a manifold (e.g., either a top manifold 712 or a bottom manifold 714 in FIG. 7), through a flow diffusion fitting 910, and into the reaction space between the conductive structure 902 and the separator 908 occupied by the reaction surface 904. Electrochemical reactions will tend to occur on the reaction surface as charge-carrying ions pass through the separator 908 into the electrolyte within the reaction space as electrolyte continues to flow along the length of the elongated element 702. When the electrolyte reaches the opposite end of the elongated element 702, it may pass through a second flow diffusion fitting 910 and into the opposite manifold. In various embodiments, the second flow diffusion fitting 910 may be configured identically to the first flow diffusion fitting or differently.

[0107] The cartridge electrodes of FIG. 7, FIG. 8, and FIG. 11 include 12 elongated electrode elements. In other embodiments, a cartridge electrode of the same or a similar type may include any number of elongated electrode elements in any length, diameter, or cross-sectional size as needed for a particular application, various examples of which are described herein.

[0108] In some embodiments, each elongated element 702 may be configured with a flow field arranged to direct electrolyte flowing therethrough in a desired path. For example, some flow fields may be configured to direct electrolyte more circumferentially than axially at some points along the length of the elongated elements 702 while directing electrolyte more axially than circumferentially at other points along the length. In this way, the residence time of the electrolyte at different axial locations may be changed to match expected rates of reactant consumption with expected rates of reactant supply along the length of the elongated elements 702. In some embodiments, flow fields may be formed by forming a pattern in the conductive structures 902, reaction surfaces 904, and / or the separators 908. Alternatively or in addition, flow fields may be provided by additional structures within or adjacent to the reaction space through which electrolyte flows. In various aspects herein, a cartridge electrode may be configured to comprise one or more radial electrolyte flow channels or flow paths. Optionally, a radial flow channel may be formed by radially providing a material such as, but not limited to, a filament, at least partially around a rod or cylindrical structure or component of the cartridge. Optionally, for example, a radial flow path or channel for electrolyte may be formed via a material radially or spirally wound around a cylindrical conductive structure described throughout herein. The radially provided material may be, for example, a polymer filament spirally wound around a central cylindrical structure or component. A radial flow channel may be configured such that an electrolyte flowing from one end of the cartridge electrode to the other end thereof will flow radially around a cylindrical structure or component of the cartridge electrode. A radial flow channel may provide benefits of enhancing mixing within an electrolyte, such as to enhance reactant transport to reaction surface and product withdrawal, and / or controlling electrolyte flow velocity or transport rate.

[0109] As shown in FIG. 8, in some embodiments, one or more sheets 850 of porous metallic material may be provided to cover both planar faces outside of the array of elongated elements 702. In some embodiments, such sheets 850 may be secured to the upper and lower manifolds 712, 714. The sheet 850 may be made of a metallic mesh, metallic foam, or perforated metallic sheet made of a metal resistant to degradation by the electrolyte in use. For example, the sheet may be made of a stainless steel, titanium, or others. By securing the sheet 850 to non-conductive structures of the cartridge electrode, it may be electrically non-polarized when in use. When cartridge electrodes with cover sheets are used as anodes in an electrowinning system, the sheets may beneficially prevent dendrites from reaching and damaging the elongated element electrodes 702.

[0110] While examples are shown and described herein with reference to cylindrical elongated elements and membranes, similar benefits may be achieved with other cross-sectional shapes, such as elliptical, ovoid, polygonal, or others. For example, any or all of the conductive structure 902, reaction surface 904, or separator 908 may have a non-cylindrical elongated shape. Also, while the cartridge electrodes of FIG. 7, FIG. 8, and FIG. 11 are shown with long axes of the elongated elements oriented vertically, they may alternatively be oriented horizontally or at any angle between vertical and horizontal.

[0111] As shown in FIG. 11, cartridge electrodes such as those shown in FIG. 7 and FIG. 8 may be paired with planar electrodes 212 in various electrochemical cell systems. For example, in some embodiments, the arrangement of FIG. 11 may represent an electrowinning cell in which the cartridge electrode 700 is an anode through which an anolyte may flow as described above, while the planar electrodes 212 may be cathodes exposed to the bath electrolyte 222 which may contain dissolve metallic ions to be electroplated onto the cathodes. In some embodiments, electroplating cathodes may be masked with a chemically-resistant non-conductive material in order to produce electroplated segments of a desired shape, such as circles, squares, rectangles, polygons, etc.

[0112] Alternatively, the arrangement of FIG. 11 may represent an acid regeneration cell such as those described in the '604 patent. In such an arrangement, the cartridge electrode 700 is a cathode through which a catholyte electrolyte (e.g., containing ferric ions to be cathodically reduced to ferrous ions) may flow, and the bath electrolyte 222 may be an anolyte from which oxygen may be evolved in an anodic water splitting reaction.

[0113] While the '604 patent and some examples herein are described with reference to iron electrowinning systems, the cartridge electrodes described herein may also be used for other applications, such as electrowinning of other metals (e.g., Cu, Zn, Ni, Co, Au, Ag, Cd, rare earth elements, or others). Alternatively, cartridge electrodes such as those described herein may be configured for electrochemical water electrolysis cells, flow batteries, electrosynthesis cells, or other electrochemical systems.Certain Aspects and Embodiments

[0114] Various aspects are contemplated and disclosed herein, a plurality of which is set forth in the paragraphs below. It is explicitly contemplated and disclosed that any aspect or portion thereof can be combined to form an aspect. In addition, it is explicitly contemplated and disclosed that: any reference to Aspect 1 includes reference to Aspects 1a, 1b, 1c, 1d, 1e, and / or 1f; any reference to Aspect 19 includes reference to Aspects 19a and / or 19b; and so on (any reference to an aspect includes reference to that aspect's lettered versions). Moreover, the terms “any preceding aspect” and “any one of the preceding aspects” means any aspect that appears prior to the aspect that contains such phrase (for example, the sentence “Aspect 4: The electrode or method of any of the preceding Aspects . . . ” means that any Aspect prior to Aspect 4 is referenced, including letter versions, including aspects 1a through 3). For example, it is contemplated and disclosed that, optionally, any method, any step, any system, any subsystem, any composition, etc., according to any of the below aspects may be useful with or combined with any other aspect(s) provided below. Further, for example, it is also contemplated and disclosed that any embodiment or aspect described above may, optionally, be combined with any of the below listed aspects.

[0115] Aspect 1a: A cartridge electrode for use in an electrochemical system, the cartridge electrode comprising:

[0116] a support bar at a top portion of the apparatus;

[0117] a plurality of elongated electrode elements, each elongated electrode element comprising:

[0118] a conductive structure;

[0119] a tubular separator;

[0120] a reaction space between the conductive structure and the separator; and

[0121] a reaction surface within the reaction space;

[0122] an in-flow manifold configured to direct a cartridge electrolyte through the reaction space of each of the elongated electrode elements; and

[0123] an out-flow manifold configured to receive the cartridge electrolyte exiting each of the reaction spaces of the elongated electrode elements.

[0124] Aspect 1b: A method for operating an electrochemical system, the method comprising:performing an electrochemical oxidation reaction or an electrochemical reduction reaction at cartridge electrode, the cartridge electrode comprising:a plurality of elongated electrode elements, each elongated electrode element comprising:

[0126] a conductive structure;

[0127] a tubular separator;

[0128] a reaction space between the conductive structure and the separator; and

[0129] a reaction surface within the reaction space;

[0130] an in-flow manifold configured to direct a cartridge electrolyte through the reaction space of each of the elongated electrode elements; andan out-flow manifold configured to receive the cartridge electrolyte exiting each of the reaction spaces of the elongated electrode elements.

[0131] Aspect 1c: The electrode or method of Aspect 1 comprising a support bar configured to retain the elongated electrode elements. Aspect 1d: The electrode or method of Aspect 1 comprising a support bar configured to retain the elongated electrode elements directly or indirectly. Aspect 1e: The electrode or method of Aspect 1 comprising a support bar configured to retain the elongated electrode elements, the support bar being at a top portion of the system. Aspect 1f: The electrode or method of Aspect 1 comprising a support bar configured to retain the elongated electrode elements and being directly or indirectly in physical contact with each of the elongated electrode elements.

[0132] Aspect 2: The electrode or method of Aspect 1, wherein the separator separates the cartridge electrolyte from a counter-electrolyte outside of the separators.

[0133] Aspect 3: The electrode or method of Aspect 1 or Aspect 2, wherein the separator membrane is electronically non-conductive and ionically conductive.

[0134] Aspect 4: The electrode or method of any of the preceding Aspects, wherein the reaction surface comprises a porous electrically conductive structure.

[0135] Aspect 5: The electrode or method of any of the preceding Aspects, wherein the reaction surface comprises a mesh, a felt, or a foam of an electrically conductive material.

[0136] Aspect 6: The electrode or method of any of the preceding Aspects, wherein the reaction surface comprises carbon, graphite, graphene, or a combination thereof.

[0137] Aspect 7: The electrode or method of any of the preceding Aspects, wherein each conductive structure is electrically connected to the support bar.

[0138] Aspect 8: The electrode or method of any of the preceding Aspects, wherein each conductive structure is cylindrical in shape.

[0139] Aspect 9: The electrode or method of any of the preceding Aspects, wherein the tubular separator comprises an ion-exchange resin.

[0140] Aspect 10: The electrode or method of any of the preceding Aspects, wherein the tubular separator comprises an anion exchange resin.

[0141] Aspect 11: The electrode or method of any of the preceding Aspects, wherein the tubular separator comprises a cation exchange resin.

[0142] Aspect 12: The electrode or method of any of the preceding Aspects, wherein the in-flow manifold is positioned below the plurality of elongated electrode elements.

[0143] Aspect 13: The electrode or method of any of the preceding Aspects, wherein the in-flow manifold is positioned above the plurality of elongated electrode elements.

[0144] Aspect 14: The electrode or method of any of the preceding Aspects, further comprising a flow diffuser coupling each elongated electrode element to the in-flow manifold.

[0145] Aspect 15: An electrowinning system comprising a plurality of cartridge electrodes as recited in any of Aspects 1-14, said cartridge electrodes being electrically polarized as electrolytic anodes and positioned in a catholyte bath adjacent to a plurality of cathode electrodes configured to receive an electrodeposited metal.

[0146] Aspect 16: The system or method of Aspect 15, wherein the electrodeposited metal is iron.

[0147] Aspect 17: An acid regeneration system comprising a plurality of cartridge electrodes as recited in any of Aspects 1-4, said cartridge electrodes being electrically polarized as electrolytic cathodes and positioned in an anolyte bath and positioned adjacent to a plurality of anodes.

[0148] Aspect 18: The system or method of Aspect 17, wherein the anodes are polarized at an anodic potential sufficient to perform an oxygen evolution reaction.

[0149] Aspect 19a: An electrochemical system in which a first electrode is in contact with a first electrolyte, a second electrode is in contact with a second electrolyte; the first electrolyte and the second electrolyte being separated by an ionically conductive separator; wherein a position of the separator relative to one of the electrodes is maintained by maintaining a pressure differential between the first electrolyte and the second electrolyte.

[0150] Aspect 19b: A method for operating an electrochemical system, the method comprising performing an electrochemical oxidation reaction or an electrochemical reduction reaction at an electrode of the electrochemical system, wherein the system comprises: a first electrode is in contact with a first electrolyte, a second electrode is in contact with a second electrolyte; the first electrolyte and the second electrolyte being separated by an ionically conductive separator; wherein a position of the separator relative to one of the electrodes is maintained by maintaining a pressure differential between the first electrolyte and the second electrolyte.

[0151] Aspect 20: The system or method of Aspect 19, wherein the pressure difference is maintained by a vacuum pump or a suction pump.

[0152] Aspect 21: The system or method of Aspect 19, wherein the pressure difference maintained by a difference in surface level between the first electrolyte and the second electrolyte.

[0153] Aspect 22a: The system, electrode, or method of any preceding Aspect, wherein the cartridge electrolyte follows a radial or spiral flow path within the cartridge electrode. Aspect 22b: The method of any preceding Aspect, comprising flowing the cartridge electrolyte radially or spirally within the cartridge electrode. Aspect 22c: The system or method of any preceding Aspect, wherein the cartridge electrolyte follows a radial or spiral flow path directly or indirectly around the conductive structure, the conductive structure having a cylindrical shape.

[0154] Aspect 23a: The system, electrode, or method of any preceding Aspect, wherein the tubular separator is a heterogeneous material. Aspect 23b: The system or method of any preceding Aspect, wherein the tubular separator comprises a heterogeneous material. Aspect 23c: The system or method of any preceding Aspect, wherein the tubular separator is formed of a heterogeneous material comprising one or more polymers and one or more ceramic materials.

[0155] Aspect 24a: The system, electrode, or method of any preceding Aspect, wherein the conductive structure and the tubular separator are coaxial. Aspect 24b: The system or method of any preceding Aspect, wherein each of the conductive structure and the tubular separator independently has a cylindrical shape and wherein the conductive structure and the tubular separator are concentric.

[0156] Aspect 25: The system, electrode, or method of any preceding Aspect, wherein each of the elongated electrode elements is parallel (to within approximately 5°) with respect to each other elongated electrode element.

[0157] Aspect 26: The system, electrode, or method of any preceding Aspect, wherein the electrochemical system is a metal electrowinning (or, metal electroplating) system or wherein the electrochemical system comprises a metal electrowinning cell.

[0158] Aspect 27: The system, electrode, or method of Aspect 26, wherein the each of the elongated electrode elements comprises an anode of the electrochemical system.

[0159] Aspect 28: The system, electrode, or method of any preceding Aspect, wherein the reaction surface is configured to maintain at least partial physical contact with the conductive structure and concurrently at least partial physical contact with the tubular separator during operation of the electrochemical system.

[0160] Aspect 29: The system, electrode, or method of any preceding Aspect, wherein each elongated electrode element is provided vertically between the in-flow manifold and the out-flow manifold.

[0161] Aspect 30: The system, electrode, or method of any preceding Aspect, wherein each elongated electrode is approximately parallel (optionally within approximately 20° of parallel) with respect to each other elongated electrode.Statements Regarding Incorporation by Reference and Variations

[0162] All references throughout this application, for example patent documents including issued or granted patents or equivalents; patent application publications; and non-patent literature documents or other source material; are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in this application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).

[0163] The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of any particular claimed invention. Thus, it should be understood that although inventions have been specifically disclosed by preferred embodiments, exemplary embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of inventions as defined by the appended claims. The specific embodiments provided herein are examples of useful embodiments of the inventions and it will be apparent to one skilled in the art that the inventions may be carried out using a large number of variations of the devices, device components, methods steps set forth in the present description. As will be obvious to one of skill in the art, methods and devices useful for the present methods can include a large number of optional composition and processing elements and steps.

[0164] As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise. Thus, for example, reference to “a cell” includes a plurality of such cells and equivalents thereof known to those skilled in the art. As well, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably. The expression “of any of claims XX-YY” (wherein XX and YY refer to claim numbers) is intended to provide a multiple dependent claim in the alternative form, and in some embodiments is interchangeable with the expression “as in any one of claims XX-YY.”

[0165] When a group of substituents is disclosed herein, it is understood that all individual members of that group and all subgroups, including iron oxide materials of an ore or structural and compositional polymorphs of the group members, are disclosed separately. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and sub-combinations possible of the group are intended to be individually included in the disclosure. When a compound is described herein such that a particular isomer, enantiomer or diastereomer of the compound is not specified, for example, in a formula or in a chemical name, that description is intended to include each isomers and enantiomer of the compound described individual or in any combination. Additionally, unless otherwise specified, all isotopic variants of compounds disclosed herein are intended to be encompassed by the disclosure. For example, it will be understood that any one or more hydrogens in a molecule disclosed can be replaced with deuterium or tritium. Isotopic variants of a molecule are generally useful as standards in assays for the molecule and in chemical and biological research related to the molecule or its use. Methods for making such isotopic variants are known in the art. Specific names of compounds are intended to be exemplary, as it is known that one of ordinary skill in the art can name the same compounds differently.

[0166] With regard to salts of the compounds herein, one of ordinary skill in the art can select from among a wide variety of available counterions those that are appropriate for preparation of salts of this invention for a given application. In specific applications, the selection of a given anion or cation for preparation of a salt may result in increased or decreased solubility of that salt.

[0167] Every device, system, subsystem, method, process, component, and / or combination of components, described or exemplified herein can be used to practice any claimed invention(s), unless otherwise stated.

[0168] Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.

[0169] All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the disclosed devices, systems, methods, and processes pertain. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art as of their publication or filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art. For example, when composition of matter are claimed, it should be understood that compounds known and available in the art prior to Applicant's inventions, including compounds for which an enabling disclosure is provided in the references cited herein, are not intended to be included in the composition of matter claims herein.

[0170] As used herein, “comprising” is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, “consisting of” excludes any element, step, or ingredient not specified in the claim element. As used herein, “consisting essentially of” does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms “comprising”, “consisting essentially of” and “consisting of” may be replaced with either of the other two terms. The claimed inventions illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

[0171] One of ordinary skill in the art will appreciate that starting materials, reagents, synthetic methods, purification methods, analytical methods, and assay methods other than those specifically exemplified can be employed in the practice of the claimed inventions without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in these inventions.

Examples

Embodiment Construction

[0055]In the following description, numerous specific details of devices, device components and methods are set forth to provide a thorough explanation of the precise nature of the various inventions described herein. It will be apparent, however, to those of skill in the art that the various inventions can be practiced without these specific details. Without wishing to be bound by any particular theory, there may be discussion herein of beliefs or understandings of underlying principles relating to the devices and methods disclosed herein. It is recognized that regardless of the ultimate correctness of any mechanistic explanation or hypothesis, an embodiment of devices and methods may nonetheless be operative and useful.

[0056]Applicant has previously described systems and methods for electrowinning of metallic iron from iron-containing feedstocks such as iron-containing ores and waste materials as described for example in U.S. Pat. No. 11,767,604 (“the '604 patent”), which is incor...

Claims

1. A cartridge electrode for use in an electrochemical system, the cartridge electrode comprising:a plurality of elongated electrode elements, each elongated electrode element comprising:a conductive structure;a tubular separator;a reaction space between the conductive structure and the separator; anda reaction surface within the reaction space;an in-flow manifold configured to direct a cartridge electrolyte through the reaction space of each of the elongated electrode elements; andan out-flow manifold configured to receive the cartridge electrolyte exiting each of the reaction spaces of the elongated electrode elements.

2. The electrode of claim 1 comprising a support bar configured to retain the elongated electrode elements.

3. The electrode of claim 1, wherein the tubular separator separates the cartridge electrolyte from a counter-electrolyte outside of the separators.

4. The electrode of claim 1, wherein the separator membrane is electronically non-conductive and ionically conductive.

5. The electrode of claim 1, wherein the reaction surface comprises a porous and electrically conductive structure.

6. The electrode of claim 1, wherein the reaction surface comprises a mesh, a felt, or a foam of an electrically conductive material.

7. The electrode of claim 1, wherein the reaction surface comprises carbon, graphite, graphene, or a combination thereof.

8. The electrode of claim 2, wherein the conductive structure of each elongated electrode element is electrically connected to the support bar.

9. The electrode of claim 1, wherein the conductive structure of each elongated electrode element is cylindrical in shape.

10. The electrode of claim 1, wherein the tubular separator comprises an ion-exchange resin.

11. The electrode of claim 1, wherein the tubular separator comprises an anion exchange resin.

12. The electrode of claim 1, wherein the tubular separator comprises a cation exchange resin.

13. The electrode of claim 1, wherein the in-flow manifold is positioned below the plurality of elongated electrode elements.

14. The electrode of claim 1, wherein the in-flow manifold is positioned above the plurality of elongated electrode elements.

15. The electrode of claim 1, further comprising a flow diffuser coupling each elongated electrode element to the in-flow manifold.

16. An electrowinning system comprising a plurality of cartridge electrodes as recited in claim 1, said cartridge electrodes being electrically polarized as electrolytic anodes and positioned in a catholyte bath adjacent to a plurality of cathode electrodes configured to receive an electrodeposited metal.

17. The system of claim 16, wherein the electrodeposited metal is iron.

18. An acid regeneration system comprising a plurality of cartridge electrodes as recited in claim 1, said cartridge electrodes being electrically polarized as electrolytic cathodes and positioned in an anolyte bath and positioned adjacent to a plurality of anodes.

19. The system of claim 18, wherein the anodes are polarized at an anodic potential sufficient to perform an oxygen evolution reaction.

20. The electrode of claim 1, wherein each elongated electrode element is provided vertically between the in-flow manifold and the out-flow manifold.

21. The electrode of claim 1, wherein each elongated electrode is approximately parallel with respect to each other elongated electrode.

22. A method of operating an electrochemical system, the method comprising:performing an electrochemical oxidation reaction or an electrochemical reduction reaction at a cartridge electrode comprising:a plurality of elongated electrode elements, each elongated electrode element comprising:a conductive structure;a tubular separator;a reaction space between the conductive structure and the separator; anda reaction surface within the reaction space;an in-flow manifold configured to direct a cartridge electrolyte through the reaction space of each of the elongated electrode elements; andan out-flow manifold configured to receive the cartridge electrolyte exiting each of the reaction spaces of the elongated electrode elements.

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