WO2024054650A2

WO2024054650A2 - Molten salt electrolytic cell and related systems and methods

Info

Publication number: WO2024054650A2
Application number: PCT/US2023/032319
Authority: WO
Inventors: Thomas Anthony VILLALON, Jr.; Richard Robert SALVUCCI; Henry Chase HUTCHESON
Original assignee: Phoenix Tailings, Inc.
Priority date: 2022-09-09
Filing date: 2023-09-08
Publication date: 2024-03-14
Also published as: WO2024054650A3; TW202413730A

Abstract

The present disclosure is related to molten salt electrolytic cells and related systems and methods.

Description

MOLTEN SALT ELECTROLYTIC CELL AND RELATED SYSTEMS AND

METHODS

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63/405,036, filed September 9, 2022, and entitled “MOLTEN SALT ELECTROLYTIC CELL AND RELATED SYSTEMS AND METHODS,” which is incorporated herein by reference in its entirety for all purposes.

TECHNICAL FIELD

Molten salt electrolytic cells and related systems and methods are generally described.

SUMMARY

The present disclosure is related to molten salt electrolytic cells and related systems and methods. The subject matter of the present invention involves, in some cases, interrelated products, alternative solutions to a particular problem, and/or a plurality of different uses of one or more systems and/or articles.

Certain aspects are related to systems for metal extraction. In some embodiments, the system comprises a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the system is configured such that, when the system is electrolytically extracting metal and the extractor is being used to remove metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the system, and wherein the system is configured such that, when the system is electrolytically extracting metal, electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the system.

In certain embodiments, the system comprises a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the system is configured such that, when the system is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte within the container, a maximum current passed between the anode and the cathode is less than or equal to 200% of current passed between the anode and the cathode immediately prior to inserting the extractor.

In some embodiments, the system comprises a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the extractor is not between the anode and the cathode.

In certain embodiments, the system comprises a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the extractor extends into the container through a top of the container.

Certain aspects are related to methods. In some embodiments, the method comprises removing molten metal that is the product of an electrolytic reaction of an electrolytic cell using an extractor that extends at least partially into the electrolytic cell while simultaneously electrolytically extracting a molten metal from a metal-containing material within the electrolytic cell, wherein the electrolytic cell comprises a cathode, an anode, and an electrolyte, and wherein, when the electrolytic cell is electrolytically extracting metal and the extractor is being used to remove metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the electrolytic cell and electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the electrolytic cell.

In some embodiments, the method comprises removing molten metal that is the product of an electrolytic reaction of an electrolytic cell using an extractor that extends at least partially into the electrolytic cell while simultaneously electrolytically extracting a molten metal from a metal-containing material within the electrolytic cell, wherein the electrolytic cell comprises a cathode, an anode, and an electrolyte, and wherein, when the electrolytic cell is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte, a maximum current passed between the anode and the cathode is less than or equal to 200% of current passed between the anode and the cathode immediately prior to inserting the extractor.

In some embodiments, the method comprises removing molten metal that is the product of an electrolytic reaction of an electrolytic cell from the top of the electrolytic cell while simultaneously electrolytically extracting a molten metal from a metalcontaining material within the electrolytic cell, wherein the electrolytic cell comprises a cathode, an anode, and an electrolyte.

In certain embodiments, the method comprises removing molten metal that is the product of an electrolytic reaction of an electrolytic cell from the electrolytic cell while simultaneously electrolytically extracting a molten metal from a metal-containing material within the electrolytic cell, wherein the electrolytic cell comprises a cathode, an anode, and an electrolyte.

Certain aspects are related to electrolytic cells for metal extraction. In some embodiments, the electrolytic cell comprises a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the internal surface of the collection vessel is accessible from the exterior of the electrolytic cell when the cathode is positioned within the cell and in a configuration in which electrolysis can be performed.

Other advantages and novel features of the present invention will become apparent from the following detailed description of various non-limiting embodiments of the invention when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and/or inconsistent disclosure, the present specification shall control.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale unless otherwise indicated. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention. In the figures:

FIG. 1A is, in accordance with certain embodiments, a cross-sectional schematic illustration showing a system comprising an electrolytic cell.

FIGS. 1B-1C are cross-sectional schematic diagrams showing arrangements of an anode, cathode, and extractor, according to some embodiments.

FIG. ID is, in accordance with certain embodiments, a cross-sectional schematic illustration showing a system comprising an electrolytic cell.

FIG. 2 is, in accordance with certain embodiments, a top view schematic illustration of the system shown in FIG. 1A.

FIG. 3 is, in accordance with certain embodiments, a cross-sectional schematic illustration showing a method of molten metal extraction.

DETAILED DESCRIPTION

Molten salt electrolytic cells and related systems and methods are generally described. Certain aspects of the present disclosure are directed to the discovery that the use of a molten salt electrolytic cell having a certain configuration and/or geometry may allow for semicontinuous or continuous extraction of molten metal from a metalcontaining material. The electrolytic cell and/or associated components (e.g., extractor, collection vessel, anode, and/or cathode) may have particularly advantageous designs that allow for high-throughput metal extraction. For example, the electrolytic cell may allow for extraction of molten metal without having to disassemble the electrolytic cell and/or remove the cathode and/or anode. The electrolytic cell may allow, in some embodiments, for extraction of molten metal while electrolysis is being performed using the electrolytic cell. The electrolytic cell may allow, in some embodiments, for removal of molten metal via the top of the electrolytic cell without substantially disturbing cell performance and/or the performance of the extractor. Certain embodiments are related to the discovery that the process can provide, in certain instances, one or more of a variety of operational advantages including, but not limited to, reduced downtime during operation and/or higher metal extraction efficiency.

In some embodiments, methods are provided. The methods can involve, in certain embodiments, removing molten metal that is the product of an electrolytic reaction of an electrolytic cell from the electrolytic cell. In some embodiments, as molten metal is removed, additional molten metal extraction from a metal-containing material within the electrolytic cell may be simultaneously performed via electrolytic reactions. In accordance with some such embodiments, simultaneous metal extraction and removal may facilitate higher throughput metal extraction. In some embodiments, systems for molten metal extraction are also provided. For example, systems capable of being employed for carrying out semicontinuous molten metal extraction are described.

FIGS. 1A-3 are schematic illustrations of one set of such systems and electrolytic cells that can be used for extracting molten metal from a metal-containing material. These figures are referred to throughout the disclosure below.

In some embodiments, an electrolytic cell for metal extraction is provided. In some embodiments, the electrolytic cell is used to produce molten metal(s). The term “electrolytic cell,” as used herein, refers to a device in which electrical energy is input into the device to drive a non- spontaneous redox reaction. The electrolytic cell can comprise, in accordance with certain embodiments, a container, an electrolyte within the container, an anode, and a cathode. Referring to FIG. 1A, for example, system 100 comprises electrolytic cell 102. In FIG. 1A, electrolytic cell 102 comprises container 112, electrolyte 108 within container 112, anode 104, and cathode 106. Typically, operation of the electrolytic cell proceeds as follows. A source of electrical energy (e.g., source 110 in FIG. 1 A) can be connected to the anode and the cathode, and electrical energy from the source can be used to drive a non spontaneous redox reaction between the anode and the cathode. The source of electrical energy (e.g., an AC power source, a battery, or any other suitable source) can be used to generate a potential difference between the anode and the cathode that forces electrons to flow from the anode to the cathode, which drives the nonspontaneous redox reaction. At the anode, an oxidation half reaction generally occurs, whereas at the cathode, a reduction half-reaction generally occurs. The electrolyte is generally used to facilitate the transport of ions between the anode and the cathode, which balances the charges within the cell as electrons are transported between the anode and the cathode. In some embodiments, during an electrolytic reaction, molten metal may be formed on the surface of the cathode and/or anode.

In certain embodiments, the electrolytic cell contains molten metal(s), for example, within the container of the electrolytic cell. As shown in FIG. 1A, for example, container 112 of electrolytic cell 102 contains molten metal(s) 121. In some embodiments, the electrolytic cell contains molten metal(s) having a density greater than a density of the electrolyte, for example, within the container of the electrolytic cell. In some embodiments, the electrolytic cell contains molten metal(s) having a density less than a density of the electrolyte, for example, within the container of the electrolytic cell. Examples of molten metals that can be contained within the electrolytic cell include, but are not limited to, zinc, cadmium, calcium, aluminum, iron, vanadium, tin, silicon, lanthanides, and/or lanthanide ferroalloys. The “lanthanides,” as used herein, are lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Other exemplary molten metals include rare earth metals. The “rare earth metals,” as used herein, are cerium (Ce), lanthanum (La), praseodymium (Pr), neodymium (Nd), promethium (Pm), europium (Eu), gadolinium (Gd), samarium (Sm), dysprosium (Dy), yttrium (Y), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), yttrium (Y), scandium (Sc), and/or lutetium (Lu). In some embodiments, the molten metal does not comprise aluminum. In some embodiments, the molten metal contained in the electrolytic call may comprise one or more alkali metals. The “alkali metals,” as used herein, are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). In some embodiments, the molten metal contained in the electrolytic call may comprise one or more alkaline earth metals. The “alkaline earth metals,” as used herein, are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). In some cases, the molten metal contained in the electrolytic cell may comprise one or more transition metals. The “transition metals,” as used herein, are scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y) zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), rubidium (Ru), palladium (Pd), silver (Ag), cadmium (Cd), lutetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), and mercury (Hg).

The molten metal that is contained within the electrolytic cell can be, for example, a product of the reduction reaction (e.g., as part of a redox reaction mechanism or other mechanism involving a reduction reaction) the electrolytic cell is configured to carry out. In some embodiments, the product of the reduction reaction does not comprise aluminum. In other embodiments, the product of the reduction reaction may comprise aluminum.

In some embodiments, the system comprises an electrolytic cell. In some embodiments, the system comprises a molten salt electrolytic cell. According to some embodiments, the system for metal extraction comprises a container. In some embodiments, an electrolyte is within the container, an anode is at least partially within the container, and a cathode is at least partially within the container. In some cases, a collection vessel is within the container and the collection vessel has an internal surface that faces the cathode. In some embodiments, an extractor at least partially within the container is present. In some embodiments, the extractor can be used to remove metal. For example, in some embodiments, the extractor can be inserted into a container of the electrolytic cell, collect molten metal from within the container, and then be removed from the container of the electrolytic cell. The extractor can, in some cases, be at least partially submerged into the electrolyte of the electrolytic cell to remove molten metal from the electrolyte of the electrolytic cell.

According to some embodiments the system is configured such that, when the system is electrolytically extracting metal and the extractor is being used to remove molten metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the system. In some cases, the system is configured such that, when the system is electrolytically extracting metal and the extractor is being used to remove molten metal, electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the system. It should be understood that, in this context, no corrosion falls within the bounds of corrosion at a rate of less than or equal to 3 g. Similarly, in this context, no electrodeposition falls within the bounds of deposition at a rate of less than or equal to 3 g- According to some embodiments, when the system is electrolytically extracting metal using an extractor and the extractor is being used to remove molten metal, the extractor corrodes and/or a material is electrodeposited on the extractor at a relatively low rate(s). This may be advantageous, for example, because when the extractor operates in this fashion, the extractor can avoid significantly affecting the electrolytic extraction of the metal by the electrolytic cell of the system, in some cases. Moreover, according to some embodiments, avoiding corrosion of and/or electrodeposition onto the extractor may facilitate using the extractor for a longer time (e.g., longer continuous operation of the cell and/or throughout more electrolytic extractions) than in cases where the extractor corrodes and/or has a material electrodeposited onto it.

For example, in some embodiments, when the extractor is being used to remove molten metal when the system is electrolytically extracting metal, the extractor corrodes at a rate of less than or equal to 3 g, less than or equal to 2.5 g, less than or equal to 2 g, less than or equal to 1.5 g, less than or equal to 1 g, less than or equal to 0.5 g, less than or equal to 0.25 g, less than or equal to 0.2 g, less than or equal to 0.1 g, or less of material of the extractor per mAh of charge passed through the system.

In some cases, when the extractor is being used to remove molten metal when the system is electrolytically extracting metal, a material may be electrodeposited onto the extractor at a rate of less than or equal to 3 g, less than or equal to 2.5 g, less than or equal to 2 g, less than or equal to 1.5 g, less than or equal to 1 g, less than or equal to 0.5 g, less than or equal to 0.25 g, less than or equal to 0.2 g, less than or equal to 0.1 g, or less of material onto the extractor per mAh of charge passed through the system.

In some cases, when the extractor is being used to remove molten metal when the system is electrolytically extracting metal, the metal that is being extracted is electrodeposited onto the extractor at a rate of less than or equal to 3 g, less than or equal to 2.5 g, less than or equal to 2 g, less than or equal to 1.5 g, less than or equal to 1 g, less than or equal to 0.5 g, less than or equal to 0.25 g, less than or equal to 0.2 g, less than or equal to 0.1 g, or less of the metal onto the extractor per mAh of charge passed through the system.

Some aspects are related to methods of using such systems. For example, in some cases, the method comprises removing molten metal that is the product of an electrolytic reaction of an electrolytic cell using an extractor that extends at least partially into the electrolytic cell while simultaneously electrolytic ally extracting a molten metal from a metal-containing material within the electrolytic cell where the electrolytic cell comprises a cathode, an anode, and an electrolyte. In some embodiments, when the system is electrolytically extracting metal and the extractor is being used to remove molten metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the system and electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the system.

In some embodiments, the extractor is used to remove molten metal from the system without being between the anode and the cathode. Such arrangements are explained in more detail below.

According to some embodiments, the system may be configured such that the electrolytic extraction is not significantly affected by the insertion and/or presence of the extractor. In some embodiments, the extractor does not significantly alter the electric field between the anode and cathode, for example, by shorting the circuit between the anode and cathode (e.g., by providing an alternative, lower electronically resistive route for current to pass).

According to some embodiments, the system may be configured such that, when the system is extracting metal, within 10 seconds of inserting the extractor into the electrolyte within the container, a maximum current passed between the anode and the cathode is less than or equal to 200% of current passed between the anode and the cathode immediately prior to inserting the extractor (e.g., while the system is extracting metal). In some cases, the maximum current passed between the anode and the cathode within 10 seconds of inserting the extractor into the electrolyte while the system is extracting metal may be less than or equal to 175%, less than or equal to 150%, less than or equal to 140%, less than or equal to 130%, less than or equal to 125%, less than or equal to 120%, or less than or equal to 115% of the current passed between the anode and the cathode immediately prior to inserting the extractor into the system when extracting metal.

In some cases, the system for metal extraction comprises an anode, a cathode, and an extractor. In some such cases, the extractor is not between the anode and the cathode when it is used to extract molten metal. To be “between the anode and cathode,” as used herein, means that the extractor is positioned such that at least one line can pass through the anode, the extractor, and the cathode, in that order. For instance, consider FIG. IB, which is a cross-sectional diagram of a cell wherein extractor 122 lies along dashed line 190 that passes through the anode 104, then the extractor 122, and then the cathode 106. Thus, the extractor 122 is between the anode 104 and the cathode 106 in FIG. IB. In contrast, FIG. 1C shows an alternative cross-sectional diagram of a cell wherein dashed line 192 passes through the anode 104, then the cathodel06, and then the extractor 122. Thus, the extractor 122 is not between the anode 104 and the cathode 106. Note that such an analysis may analogously be performed for three-dimensional anodes, cathodes, and extractors.

In some cases, the extractor extends into the container through a top of the container, for example, where the top of the container comprises an opening.

In some embodiments, the anode and/or cathode may be at least partially disposed within the container. The anode and/or cathode, according to some embodiments, may be at least partially immersed in the electrolyte. For example, as shown in FIG. 1A, anode 104 and/or cathode 106 are at least partially immersed within container 112. The anode and/or cathode, in accordance with certain embodiments, can be at least partially immersed in an electrolyte within the container. As used herein, “at least partially” means some or all. In some embodiments, at least partially refers to at least 10 vol% (and/or at least 20 vol%, at least 30 vol%, at least 40 vol%, at least 50 vol%, at least 60 vol%, at least 70 vol%, at least 80 vol%, or more) and/or up to 90 vol% (and/or up to 95 vol%, up to 99 vol%, or up to 100 vol%). According to some embodiments, at least partial immersion of the anode and cathode in the electrolyte may result in a complete electrical circuit between the anode, the cathode, and the power source. In some such embodiments, upon application of a sufficient driving force via the power source (e.g., power source 110 in FIG. 1A), one or more non-spontaneous redox reactions may occur in the electrolytic cell.

A variety of types of materials can be used as the anode, the cathode, and the electrolyte of the electrolytic cell, and the selection of these materials generally depends on the type of redox reaction that is being driven by the electrolytic cell. Examples of materials from which the anode can be made include, but are not limited to, carbon (e.g., graphitic carbon such as graphene, graphite, and/or carbon nanotubes); and oxygen- carrying ceramics and/or cermets (e.g., yttria- stabilized zirconia (YSZ), Gd-doped ceria, and/or other ceramics and/or cermets). Examples of materials from which the cathode can be made include refractory metals, such as titanium, niobium, tungsten, molybdenum, and/or tantalum. In some cases, the material of the cathode may generally comprise relatively reactive metals, for example iron, zinc, and/or magnesium, that form oxides and/or otherwise change chemical composition from their pure form under operating conditions of the electrolytic cell. Examples of materials from which the electrolyte can be made include, but are not limited to, molten salts.

The cathode and/or anode may have any of a variety of appropriate shapes and configurations. In one set of embodiments, the cathode may have a shape that helps to direct molten metal formed on the surface of the cathode to a collection vessel. For example, according to certain embodiments, the cathode may have a tapered tip that is configured to direct flow of molten metal toward the internal surface of the collection vessel. For example, as shown in FIG. 1A, cathode 106 may comprise tapered tip 107 that is configured to direct flow of molten metal 121 toward internal surface 127 of collection vessel 125. An alternative embodiment is shown in FIG. ID where molten metal 121 is less dense than electrolyte 108, and thus floats towards internal surface 127 of collection vessel 125 in the direction of arrow 150. In this example, the collection vessel is inverted relative to the embodiment shown in FIG. 1A to collect the molten metal as it floats upward.

In one set of embodiments, the electrolyte comprises molten salt(s). Any of a variety of appropriate types of molten salts may be employed. In some embodiments, the molten salt(s) comprises a halogen-containing salt comprising a halide. In some embodiments, the molten salt(s) comprises oxygen (e.g., in oxide form). In some cases, the molten salt(s) comprises oxyhalide anions, e.g., anions containing oxygen and at least one halogen. In some cases, the oxyhalide anion comprises oxygen and chloride. In some embodiments, the oxyhalide anion comprises oxygen and fluoride. In some embodiments, the oxyhalide anion comprises oxygen, chloride, and fluoride. In some embodiments, the molten salt(s) is a mixed halide anion system, where at two types of halogen anions are present. For instance, in some cases, the molten salt comprises fluoride and chloride. In some embodiments, the molten salt comprises chloride and bromide. In some cases, the molten salt(s) comprises a sulfur-halide anion. For example, the sulfur-halide anion comprises sulfur and at least one halide (e.g., fluoride, chloride, and/or bromide).

Non-limiting examples of molten salts include alkali metal halides (e.g., sodium chloride, potassium chloride), alkaline earth metal halides, rare earth metal halides, transition metal halides (e.g., ferric chloride), and oxygen-containing salts (e.g., oxide salts containing non-bridging oxygen, oxyhalides, rare earth metal oxides). In some cases, the molten salt may include cations comprising at least one rare earth metal and/or at least one alkali metal. In some such cases, the anion of the molten salt may comprise at least one halide, at least one oxyhalide, and/or at least one sulfur-halide. In some embodiments, the anion of the molten salt may comprise a mixed halide anion system. In some cases, the molten salt may include at least one alkali metal cation and at least one halide. For example, in some cases, the molten salt may comprise lithium chloride and potassium chloride. For example, in some embodiments, the molten salt may comprise lithium fluoride and lithium chloride. In some embodiments, the molten salt may include at least one alkali metal cation, at least one rare earth metal cation, and at least one halide. For example, in some embodiments, the molten salt may comprise lithium fluoride and dysprosium fluoride.

In some embodiments, the molten salts may have a density that is less than the density of molten metals formed in the electrolytic cell. Such a density difference may allow the formed molten metals to flow in the direction of gravity to the bottom of the container, e.g., such that the molten metal may be collected by the collection vessel. In some embodiments, the molten salts may have a density that is greater than the density of molten metals formed in the electrolytic cell. Such a density difference may allow the formed molten metals to flow in the opposite direction of gravity toward (and, in some cases, to) the top of the container, e.g., such that the molten metal may be collected by an inverted collection vessel. In some embodiments, the electrolyte comprises a metalcontaining material, for example, from which metal may be electrolytically extracted. In some embodiments, the electrolyte is a metal-containing material, for example, from which metal may be electrolytically extracted. In some embodiments, the electrolyte comprises molten salt(s) and a metal containing material from which metal may be electrolytically extracted. In some embodiments, the electrolyte comprises molten salt(s) which is a metal containing material from which metal may be electrolytically extracted. The electrolytic cell can comprise, in accordance with certain embodiments, a container. In FIG. 1A, for example, electrolytic cell 102 comprises container 112. The container can have any of a variety of suitable sizes. In some embodiments, the container has an interior volume of at least 500 cm³; at least 1000 cm³; at least 10,000 cm³; at least 100,000 cm³; at least 1 m³; or at least 10 m³ (and/or up to 100 m³; up to 1000 m³; up to 10,000 m³; or greater).

The container may have any of a variety of appropriate shapes, e.g., cross- sectional shapes. Non-limiting examples include, but not limited to, rectangular, circular, oval, square, and polygonal. In one set of embodiments, the container may have an oval shaped cross-section. For example, as shown in FIG. 2, container 112 within electrolytic cell 102 has an oval shaped cross-section. In some embodiments, the container may have an irregular shape. In some embodiments, the container may comprise a lid, for example, to form a semi-closed or closed environment in which electrolysis may be performed.

In some embodiments, the electrolytic cell may be associated with a heater capable of heating the container to a temperature (e.g., to a temperature described herein). The heater may include any of a variety of heating systems (such as an internal or an external heating systems). Any of a variety of heaters and/or heating systems may be employed, including, but not limited to, a Peltier heater, a heating jacket and/or coil, a resistive heater, an open flame heater, an induction heating system, and/or a microwave. FIG. 1A illustrates a non-limiting example of an external heater, illustrated as a resistive heater. As shown, system 100 may comprise heater 130 configured to heat container 112 to an operation temperature described herein.

The electrolytic cell can be heated to and/or operated at any of a variety of temperatures. For example, in some embodiments, the spatially averaged temperature within the container of the electrolytic cell is greater than or equal to 300 °C, greater than or equal to 400 °C, greater than or equal to 500 °C, greater than or equal to 600 °C, greater than or equal to 800 °C, greater than or equal to 1000 °C and/or less than or equal to 1400 °C (e.g., less than or equal to 1200 °C, less than or equal to 1100 °C, or less). Combinations of these ranges are also possible (e.g., greater than or equal to 300 °C and less than or equal to 1400 °C, greater than or equal to 300 °C and less than or equal to 1200 °C, greater than or equal to 600 °C and less than or equal to 1100 °C). The container may be formed using any of a variety of materials, such as graphite, low carbon steel, stainless steel, and/or refractory metals. Such materials, in some embodiments, may facilitate the use of relatively high temperatures during electrolysis, as described herein. Additionally, or alternatively, the container may be coated with stabilized zirconia, hexagonal boron nitride, and/or graphite. In some embodiments, the container may be coated with relatively inert materials, for example, that do not react, decompose, and/or otherwise degrade in the presence of other materials and/or at the temperatures used in the system, as described herein.

The system can include, in some embodiments, a collection vessel. In some embodiments, the collection vessel may be removeable, e.g., may be removed from the container of the electrolytic cell. In FIG. 1A, for example, electrolytic cell 102 comprises collection vessel 125. In some embodiments, the collection vessel comprises an opening (e.g., an inlet) in fluidic communication with the container of the electrolytic cell. In FIG. 1A, collection vessel 125 comprises opening 126 that is in fluidic communication with the interior of container 112. The opening of the collection vessel may be configured such that fluid communication is established between the interior of the container and the interior of the collection vessel. For example, in FIG. 1A, opening 126 can be used as an inlet through which molten metal 121 can be transported into the interior of collection vessel 125.

Generally, the term “opening” is used herein to refer to any opening within an object, and openings can be used as inlets, as outlets, or both.

As used herein, two elements are in “fluidic communication” with each other (or, equivalently, in fluid communication with each other) when fluid may be transported from one of the elements to the other of the elements without otherwise altering the configurations of the elements or a configuration of an element between them (such as a valve).

The collection vessel, in some embodiments, may be positioned below the cathode such it can be used to collect molten metal formed on the cathode. For example, as shown in FIG. 1A, collection vessel 125 may be positioned below cathode 106 and may be employed to collect molten metal 121 formed on a surface of cathode 106 in electrolytic cell 102. In some embodiments, the collection vessel may have an internal surface having a surface area that faces the cathode. For example, referring to FIG. 1A, collection vessel 125 comprise internal surface 127 facing cathode 106. In some embodiments, the internal surface of the collection vessel is accessible from the exterior of the electrolytic cell when the cathode is positioned within the cell and in a configuration in which electrolysis can be performed. This can allow for one to access the molten metal within the electrolytic cell (e.g., for extraction) while molten metal is being electrolytically produced. In some embodiments, at least at portion of the lateral extent of the opening of the collection vessel is not covered by the cathode. For example, in some embodiments, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, and/or up to 80%, or up to 90% of the lateral extent of the opening of the collection vessel is not covered by the cathode. For example, as shown in FIG. 1A, at least a portion of the lateral extent of opening 126 of collection vessel 125 is not covered by the cathode. As used herein, the “lateral extent” of an object refers to the area that is occupied by that object when viewed from the top down. When determining the percentage of the lateral extent of the opening of the collection vessel that is “covered” by the cathode, one would observe the cell from the top down and determine the percentage of the geometric area of the opening of the collection vessel over which the cathode is positioned. FIG. 2, which illustrates a top-down view of electrolytic cell 102 of FIG. 1, can be used to illustrate this concept. In FIG. 2, the lateral extent of the opening 126 (e.g., as denoted in FIG. 1A) of the collection vessel is shown as box 125, and the lateral extent of the cathode is shown as box 106. The percentage of the lateral extent of the opening of the collection vessel that is “covered” by the cathode would be calculated by dividing the area of box 106 by the area of box 125 and multiplying by 100%. In some cases, the lateral extent of the cathode may be either partially or completely contained within the lateral extent of the collection vessel. For example, as shown in FIG. 2, the lateral extent of cathode 106 is completely contained within the lateral extent of collection vessel 125.

In some embodiments, the lateral extent of the collection vessel can be less than the lateral extent of the container. For example, in some embodiments, the lateral extent of the collection vessel can be less than or equal to 80%, less than or equal to 70%, less than or equal to 70%, less than or equal to 60%, or less than or equal to 50% (and/or, as little as 20%, at little as 10%, as little as 5%, as little as 1%, or less) of the lateral extent of the container.

The collection vessel may have any of a variety of shapes, e.g., lateral or longitudinal cross-sectional shapes. Non-limiting examples include rectangular, trapezoidal, cylindrical, circular, and oval. A non-limiting example of a collection vessel having a trapezoidal longitudinal cross-section is illustrated in FIG. 1A.

In some embodiments, the collection vessel may be completely contained with the container (e.g., as shown in FIG. 1A). In accordance with certain embodiments, locating the collection vessel completely within the container of the electrolytic cell can allow one to collect molten metal from the container of the electrolytic cell while maintaining the molten metal above its melting point.

In certain embodiments, the collection vessel is in contact with the electrolyte. The collection vessel can be in contact with the electrolyte, for example, during at least 25%, at least 50%, at least 75%, at least 90%, or all of the time that molten metal and/or molten salt is transported into the collection vessel. As illustrated in FIG. 1A, for example, collection vessel 125 is in contact with electrolyte 108. According to some embodiments, the collection vessel may be at least partially immersed in the electrolyte.

The collection vessel can have any of a variety of suitable sizes. In some embodiments, a relatively large collection vessel can be used. For example, in certain embodiments, the collection vessel has an interior volume of at least 30 cm³, at least 50 cm³, at least 80 cm³, at least 100 cm³, at least 150 cm³, at least 180 cm³, at least 250 cm³, at least 500 cm³, or at least 1000 cm³ (and/or up to 10,000 cm³; up to 100,000 cm³; up to 1 m³; or more). In accordance with some embodiments, the size of the collection vessel may be selected such that the collection vessel may be completely contained within the container. According to some embodiments, the container of the electrolytic cell may comprise the collection vessel, for example, such that the collection vessel is not detachable from the container.

The collection vessel can be made of any of a variety of suitable materials. In some embodiments, the collection vessel can be made of a material configured to withstand the high temperature environment of the container of certain electrolytic cells. For example, in some embodiments, walls of the collection vessel comprise a refractory metal and/or a ceramic. In some embodiments, at least a portion (e.g., at least 50% of, at least 75% of, at least 90% of, at least 95% of, at least 99% of, or all) of the interior surface area of the walls of the collection vessel can be made of refractory metal(s), such as titanium, niobium, tungsten, molybdenum, and tantalum.

In some embodiments, the electrolytic cell comprises an extractor at least partially contained within the collection vessel. In some cases, the portion of the extractor contained within the collection vessel may be in the form of a cup or vessel configured to hold a liquid (e.g., molten metal). The extractor may include, for example, a solid body that is configured such that it can be used to remove molten metal from the system. In some embodiments, the extractor may comprise a ladle or a siphon. In certain embodiments, the extractor comprises an elongated rod or other elongated solid body that can be at least partially immersed into the molten salt and collect molten metal. For example, as shown in FIG. 1A, electrolytic cell comprises extractor 122 that is at least partially contained with collection vessel 125. As shown, extractor 122 comprises cup 123 capable of holding a liquid (e.g., molten salt) contained within collection vessel 125. In some embodiments, the extractor may comprise an elongated handle portion extending out of the collection vessel. For example, as shown in FIG. 1A, extractor 122 comprises an elongated handle portion 120 extending outward from collection vessel 125.

In some embodiments, the extractor may be removably decoupled from and/or coupled to the container and/or collection vessel during operation of the electrolytic cell. For example, as described in more detail below, the extractor may be removed from the container and/or collection vessel and placed back into the container and/or collection vessel as desired while operating the electrolytic cell.

In some embodiments, the extractor comprises an opening in fluidic communication with the collection vessel. In some such embodiments, at least a portion of the molten metal contained with the collection vessel may be transported into the collection vessel via the opening. For example, as shown in FIG. 1A, cup 123 of extractor 122 comprises an opening (not shown) in fluidic communication with collection vessel 125. In some cases, molten metal 121 contained within the collection vessel 125 may enter into the opening of cup 123 of extractor 122. In some embodiments, the extractor is configured to remove at least a portion of molten metal from the collection vessel. As shown in FIG. 1A, extractor 122 may then be configured to remove the at least a portion of molten metal 121 from collection vessel 125.

The extractor may be positioned in any of a variety of locations within the container. In one set of embodiments, the metal extractor may comprise a first portion positioned adjacent the center of the container and a second portion positioned adjacent the side walls of the container. For example, as shown in FIG. 1A, extractor may comprise a first portion (e.g., a cup 123) positioned adjacent the center of container 112 and a second portion (e.g., elongated handle portion 122) positioned adjacent the side walls of container 112.

In some embodiments, at least a portion of the extractor is submerged in the liquid (e.g., molten metal and/or molten salts) within the collection vessel. In one set of embodiments, the cup portion of the extractor is submerged in the molten metal within the collection vessel. In some cases, the extractor may be submerged to an extent such that at least 5 vol% (e.g., at least 10 vol%, at least 25 vol%, at least 40 vol%) and/or up to 50 vol% of the liquid (e.g., molten metal and/or molten salt) within the collection vessel occupies the cup portion of the extractor. In some embodiments, the extractor is positioned such that it does not contact the anode and/or cathode of the electrolytic cell.

The extractor can be made from any of a variety of materials. For example, the surface area of the walls of the extractor and/or collection vessel can be made of refractory metal(s), such as titanium, niobium, tungsten, molybdenum, stainless steel, and tantalum. In some embodiments, at least the surface area of the walls of the collection vessel may be made of refractory metal(s) such that the collection vessel may be contained in the container and/or immersed in the electrolyte during device operation without degrading, for example, by melting. In some embodiments, at least a portion of the extractor (e.g., at least 25%, at least 50%, at least 75%, at least 90%, at least 95%, or more of the exterior surface of the extractor that contacts the molten phase within the electrolytic cell during extraction) is made of an electronically conductive material (e.g., a metal or other electronically conductive material).

In some embodiments, the electrolytic cell may have and/or may comprise components (e.g., container, cathode, collection vessel, extractor, etc.) having certain configurations that allow for efficient molten metal extraction. For example, in one embodiment, the electrolytic cell may comprise a container having an oval shaped cross- section comprising a first vertex and a second vertex associated with its major axis. As shown in FIG. 2, electrolytic cell 102 comprises container 112 having a cross-section with first vertex 132 and second vertex 134 associated with its major axis. In some cases, the container may contain a cathode and an extractor spaced a certain distance apart from the cathode. In accordance with certain embodiments, while the cathode has a cross-section that is positioned adjacent the first vertex of the oval shaped cross-section of the container, the extractor may have a cross-section that is positioned adjacent a second vertex of the oval shaped cross-section of the container. For example, as shown in FIG. 2, container may comprise cathode 106 and extractor 122 spaced a certain distance apart from cathode 106. While the cross-section of cathode 106 is positioned adjacent first vertex 132 of the oval shaped cross-section of container 112, the crosssection of extractor 122 is positioned adjacent second vertex 134 of the oval shaped cross-section of container 112.

In some embodiments, a method is provided. The method, according to some embodiments, may allow for continuous or semicontinuous processing and extraction of molten metals using a system and/or electrolytic cell described herein. For example, the method may allow for extraction of molten metal without having to disassemble the electrolytic cell and/or remove the cathode and/or anode.

In certain embodiments, the method comprises removing molten metal (e.g., using an extractor) that is the product of an electrolytic reaction of an electrolytic cell from the electrolytic cell while simultaneously electrolytically extracting a molten metal from a metal-containing material within the electrolytic cell. The metal-containing material may contain any of a variety of metals, including any of the metals described elsewhere herein with respect molten metals. In some embodiments, the metalcontaining material is in the form of a metal halide comprising a halogen atom. For the purposes of the present disclosure, the “halogen” elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). In some cases, the metal may comprise a rare earth metal, an alkali metal, an alkaline earth metal, and/or a transition metal. For example, in some embodiments, the metal containing material is or comprises neodymium chloride. In some embodiments, the metal containing material is or comprises neodymium oxide. In some embodiments, the metal containing material is or comprises lithium chloride. In some embodiments, the metal containing material is or comprises dysprosium oxide. In some embodiments, the metal-containing material comprises an anion comprising at least one halogen, oxygen, and/or sulfur. In some cases, the metal-containing material may be dissolved and/or suspended within the electrolyte. The metal-containing material, according to certain embodiments, may form part of the electrolyte. The metal-containing material may be added to the electrolyte at any appropriate time, such as prior to and/or while operating the electrolytic cell. In accordance with some embodiments, the metal-containing material may be the electrolyte, for example, when melted to form a molten salt. For instance, when the metal-containing material is a metal halide, the metal-containing material may be melted to form a molten salt comprising the metal halide.

In some embodiments, the metal containing material may comprise a rare earth metal and an oxyhalide. In some embodiments, the metal containing material may comprise a rare earth metal and a mixed halide anion system. In some embodiments, the metal containing material may comprise a rare earth metal and a sulfur halide anion system. In some embodiments, the metal containing material may comprise an alkali metal and an oxyhalide. In some embodiments, the metal containing material may comprise an alkali metal and a mixed halide anion system. In some embodiments, the metal containing material may comprise an alkali metal and a sulfur halide anion system.

In some embodiments, via an electrolytic reaction of the electrolytic cell, metal from a metal-containing material contained within the electrolyte may be electrolytically extracted as a product and deposited on the cathode and/or anode as molten metal. For example, as shown in FIG. 1A, via an electrolytic reaction of electrolytic cell 102, molten metal 121 may be electrolytically extracted from a metal-containing material within electrolyte 108 and deposited on the surface of cathode 106 as a product during operation of the electrolytic cell. In some embodiments, the metal-containing material can be fed to the electrolytic cell in solid form. In some such embodiments, the metalcontaining material can be melted within the electrolytic cell to form molten metalcontaining material. In some cases, the metal-containing material can integrate itself into the electrolyte (e.g., the molten-salt electrolyte) of the electrolytic cell. For example, in some cases, the electrolyte and the molten metal-containing material may be part of the same liquid domain. In some such embodiments, electrolytically extracting the metal from the metal-containing material may comprise reducing the metal from a cationic state to a zero-valent state, for example, reducing a cation in a molten salt or other molten material within the electrolytic cell to a zero-valent molten metal present on a surface of the cathode.

In some embodiments, the molten metal on the cathode and/or anode is subsequently collected by a collection vessel positioned under the cathode. For example, as shown in FIG. 1A, molten metal 121 on cathode 106 may be collected by collection vessel 125 positioned under cathode 106. The cathode, in some cases, may have a tapered tip (e.g., a conical, a trapezoidal, a triangular pyramidal, etc.) that is configured to direct flow of molten salt into the collection vessel. In some embodiments, due to the density of the molten metal collected on the cathode (e.g., relative to the molten salt), the molten metal may sink from the surface of the cathode to below the molten salt into the collection vessel. As noted above, in other embodiments, the molten metal may float upward and be collected by a collection vessel that is above at least a portion of the cathode.

In some embodiments, while molten metal is electrolytically extracted from the metal-containing material in the electrolyte, the already-formed molten metal contained within the collection vessel may be simultaneously removed from the vessel and the electrolytic cell. For example, as shown in FIG. 1A, already-formed molten metal 121 contained within collection vessel 125 may be simultaneously removed from collection vessel 125 while additional molten metal is being formed electrolytically on cathode 106 within electrolytic cell 102. In some embodiments, the molten metal within collection vessel may be removed or collected from the electrolytic cell using an extractor (e.g., a ladle or siphon) described herein. For example, as shown in FIG. 1A, molten metal 121 within collection vessel 125 may be removed from electrolytic cell 102 using extractor 122. In some embodiments, after removal of the molten metal, the extractor may be again placed back into the collection vessel to remove additional molten metal accumulated within the collection vessel. The above-referenced process(es) may be repeated for any appropriate number of times and/or for as long as the cell may be operated continuously.

In accordance with some embodiments, removing the molten metal using the extractor comprises inserting the extractor through an opening on the top of the electrolytic cell, collecting the molten metal from the collection vessel in the extractor, and removing the extractor containing the molten metal from the electrolytic cell for example, as shown in FIGS. 1 and 3. In some cases, removing the molten metal using the extractor comprises inserting the extractor through an opening on the top of the electrolytic cell into the collection vessel, collecting the molten metal from the collection vessel, and removing the molten metal using the extractor. For instance, when the extractor comprises a siphon, using the extractor may comprise applying a negative pressure to a portion of the extractor outside of the container of the electrolytic cell to withdraw the molten metal through the extractor and out of the container, in some embodiments.

According to some embodiments, the extractor is not in the form of a tap, for example, a tap configured to remove the molten metal from the bottom and/or side of the collection vessel. Such a tap, according to some embodiments, is not practical when the electrolytic cell is buried. In some embodiments, the electrolytic cells described herein may be buried for safety purposes, thermal stability, and/or for facilitating containment of the molten salt and/or molten metal during electrolytic extraction of metals from metal-containing materials in a molten electrolyte. Accordingly, removing the molten metal through an opening on the top of the electrolytic cell using an extractor may be advantageous, in some embodiments, because the electrolytic cell may be buried (thus making taps impractical). In other embodiments, the system may comprise a tap through which a molten metal may flow from the electrolytic cell.

According to some embodiments, the methods described herein are generally related to simultaneously electrolytically extracting molten metal from a metal containing material while removing the molten metal that is a product of the electrolytic reaction. In some cases, the molten metal is electrolytically extracted for at least a period of time (e.g., at least 1 minute, at least 5 minutes, at least 10 minutes, at least 20 minutes, at least 30 minutes, at least 45 minutes, at least 1 hour and/or up to 2 hours, up to 3 hours, or up to 4 hours) before simultaneous removal of the molten metal begins. According to some such embodiments, electrolytically extracting the molten metal is done before removing the molten metal so that there is molten metal to remove.

A current and/or electric field associated with the electrolytic reaction, in accordance with some embodiments, may be dependent on a relatively large number of parameters. For example, in some cases, the current and/or electric field may depend on the identity of the species participating in the electrolytic reaction, the materials of the anode and/or cathode, the dimensions and/or spacing between the anode and/or cathode, the temperature at which the reaction is run, the dimensions of the container, and/or the presence and/or location of an extractor.

Relatively small perturbations to the current and/or electric field when inserting an extractor during electrolytic extracting of molten metal from a metal-containing material may be beneficial, for example, for performing the electrolytic extraction efficiently, in some embodiments. In some cases, the relatively small perturbations to the electric field and/or current indicates that inserting the extractor into the electrolyte in the container does not significantly perturb the electrolytic extraction process. According to some embodiments, this may prolong the lifetime of the extractor, for instance, by minimizing and/or avoiding electrodeposition and/or corrosion on the extractor which could arise by shorting the circuit performing the electrolytic extraction. Accordingly, certain embodiments described above and elsewhere herein can be advantageous for operating electrolytic cells efficiently by including only relatively small (or no) perturbations to the current and/or electric field when inserting the extractor into the electrolytic cell.

In some embodiments, the molten metal is removed without having to remove the cathode and/or disassemble the electrolytic cell. For example, referring to FIG. 3, molten metal 121 may be lifted out of container 112 using extractor 122 and removed from container 112 without having to remove cathode 106 and/or disassemble electrolytic cell 102. The extractor may have any appropriate configuration suitable for removal of molten metal. For example, as shown in FIG. 3, extractor may have cup 123 capable of holding molten metal 121. The extractor may be sized and/or may be positioned such that it does not contact the cathode and/or anode or interfere with the electrolytic metal extraction process that is being simultaneously carried out within the electrolytic cell.

In certain embodiments in which an electrolytic cell is used to extract metal and metal is removed from it, the amount of material deposited on the extractor and/or corroded from the extractor can be relatively small. For example, in some embodiments, when the extractor is being used to remove molten metal when the electrolytic cell is electrolytically extracting metal, the extractor corrodes at a rate of less than or equal to 3 g, less than or equal to 2.5 g, less than or equal to 2 g, less than or equal to 1.5 g, less than or equal to 1 g, less than or equal to 0.5 g, less than or equal to 0.25 g, less than or equal to 0.2 g, less than or equal to 0.1 g, or less of material of the extractor per mAh of charge passed through the electrolytic cell. In some cases, when the extractor is being used to remove molten metal when the electrolytic cell is electrolytically extracting metal, a material may be electrodeposited onto the extractor at a rate of less than or equal to 3 g, less than or equal to 2.5 g, less than or equal to 2 g, less than or equal to 1.5 g, less than or equal to 1 g, less than or equal to 0.5 g, less than or equal to 0.25 g, less than or equal to 0.2 g, less than or equal to 0.1 g, or less of material onto the extractor per mAh of charge passed through the electrolytic cell. In some cases, when the extractor is being used to remove molten metal when the electrolytic cell is electrolytically extracting metal, the metal that is being extracted is electrodeposited onto the extractor at a rate of less than or equal to 3 g, less than or equal to 2.5 g, less than or equal to 2 g, less than or equal to 1.5 g, less than or equal to 1 g, less than or equal to 0.5 g, less than or equal to 0.25 g, less than or equal to 0.2 g, less than or equal to 0.1 g, or less of the metal onto the extractor per mAh of charge passed through the electrolytic cell.

The following examples are intended to illustrate certain embodiments of the present invention, but do not exemplify the full scope of the invention.

EXAMPLE 1

A molten salt system was employed to produce ferrodysprosium via continuous electrolysis using an electrolytic cell system. The electrolytic cell system contained a collection vessel or cup made from molybdenum for collecting ferrodysprosium dripped from the electrode, and a stainless steel ladle for harvesting the collected ferrodysprosium. Approximately 50% of the produced ferrodysprosium metal was harvested while the electrolytic cell system was kept under an applied voltage. Given that no major change (if any) was observed in the voltage or current of the system, the system demonstrated successful metal harvesting while allowing for a continuous electrolysis operation.

EXAMPLE 2

A 300 g bath of lithium fluoride-neodymium fluoride eutectic was created in a graphite crucible (e.g., a container), after which 5 grams of neodymium oxide was added to the bath. A tungsten collection cup was added to the bottom of the cell. Additionally, a tungsten cathode and a graphite anode were suspended above the collection cup in the bath. Electrolysis was run in the system for 2 hours without major deviations. A harvesting ladle comprising an iron cup on a rod was inserted into the bath near to, but prior to, the 2-hour mark while the cell was active. The ladle was inserted into the tungsten collection cup in the bath on the side furthest from the anode, with the cathode in between the harvesting ladle and the graphite anode to collect the electrolyzed metal (e.g., reduced metal and/or zero-valent metal) present in the collection cup. No signs of corrosion or electrodeposition were visible on the ladle after collecting the electrolyzed material. In contrast, when the ladle was inserted into the bath between the anode and the cathode, the ladle showed signs of corrosion and electrodeposition.

EXAMPLE 3

A 300 g bath of lithium fluoride-dysprosium fluoride eutectic was created in a graphite crucible (e.g., a container), after which 5 grams of dysprosium oxide was added to the bath. An iron collection cup was added to the bottom of the cell. Additionally, an iron cathode and a graphite anode were suspended above the collection cup in the bath. Electrolysis was run in the system for 2 hours without major deviations. A harvesting ladle comprising an iron cup on a rod was inserted into the bath near to, but prior to, the 2-hour mark while the cell was active. The harvesting ladle was inserted into the iron collection cup of the in the bath on the side furthest from the anode, with the cathode in between the harvesting ladle and the graphite anode, to collect electrolyzed metal (e.g., reduced metal and/or zero-valent metal) present in the collection cup. No signs of corrosion or electrodeposition were visible on the ladle after extracting the electrolyzed metal. However, when the ladle was inserted into the bath between the anode and the cathode, the ladle showed signs of corrosion and electrodeposition.

EXAMPLE 4

A 50 g bath of lithium chloride-potassium chloride eutectic was created in a stainless- steel crucible (e.g., a container), after which 2 grams of partially hydrated lithium chloride was added to the bath. A steel cathode and a graphite anode were inserted into the bath in the crucible. The steel cathode was angle out towards the edge of the stainless-steel crucible to collect the lithium metal away from anodic gases. Electrolysis was run in the system for 1 hour without major deviations. A steel scoop was prepared to collect the metal. Near to, but prior to, the 1-hour mark, while the cell was still active, the steel scoop was inserted into the cell to collect electrolyzed metal on the side furthest from the anode, with the cathode in between the harvesting ladle and the graphite anode. No signs of corrosion or electrodeposition were visible on the scoop. However, if the scoop was put in between the anode and the cathode, the ladle was noted to have signs of corrosion and electrodeposition.

EXAMPLE 5

A 300 g bath of 30 wt% lithium fluoride - 70 wt% lithium chloride was created in a graphite crucible (e.g., a container), after which 5 grams of neodymium chloride was added to the bath. A tungsten collection cup was added to the bottom of the container. A tungsten cathode and a graphite anode placed in the bath in the container to form an electrolytic cell. Electrolysis was run in the electrolytic cell for 2 hours without major deviations. A harvesting ladle was made using a cleaned welding rod and a small iron cup at the end. Near to, but prior to, the 2-hour mark, while the cell was still active, the harvesting ladle was inserted into the cell to collect electrolyzed metal on the side of the electrolytic bath furthest from the anode. The ladle was inserted such that the cathode was positioned between the ladle and the anode. No signs of corrosion or electrodeposition were visible on the ladle. Note, however, that when the ladle was positioned between the anode and the cathode when electrolysis was occurring, the ladle showed signs of corrosion and electrodeposition.

While several embodiments of the present invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the functions and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and/or methods, if such features, systems, articles, materials, and/or methods are not mutually inconsistent, is included within the scope of the present invention.

The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and/or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

As used herein, “wt%” is an abbreviation of weight percentage. As used herein, “vol%” is an abbreviation of volume percentage.

Some embodiments may be embodied as a method, of which various examples have been described. The acts performed as part of the methods may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include different (e.g., more or less) acts than those that are described, and/or that may involve performing some acts simultaneously, even though the acts are shown as being performed sequentially in the embodiments specifically described above.

Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

1. A system for metal extraction, comprising: a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the system is configured such that, when the system is electrolytically extracting metal and the extractor is being used to remove metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the system, and wherein the system is configured such that, when the system is electrolytically extracting metal, electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the system.

2. A system for metal extraction, comprising: a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the system is configured such that, when the system is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte within the container, a maximum current passed between the anode and the cathode is less than or equal to 200% of current passed between the anode and the cathode immediately prior to inserting the extractor.

3. A system for metal extraction, comprising: a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the extractor is not between the anode and the cathode.

4. A system for metal extraction, comprising: a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the extractor extends into the container through a top of the container.

5. The system of any one of claims 1-4, wherein the system is configured such that, when the system is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte within the container, the maximum current passed between the anode and the cathode is less than or equal to 175% of current passed between the anode and the cathode immediately prior to inserting the extractor.

6. The system of any one of claims 1-4, wherein the system is configured such that, when the system is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte within the container, the maximum current passed between the anode and the cathode is less than or equal to 150% of current passed between the anode and the cathode immediately prior to inserting the extractor.

7. The system of any one of claims 1-4, wherein the system is configured such that, when the system is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte within the container, the maximum current passed between the anode and the cathode is less than or equal to 125% of current passed between the anode and the cathode immediately prior to inserting the extractor.

8. The system of any one of claims 1-7, wherein the system comprises an electrolytic cell.

9. The system of any one of claims 1-8, wherein the extractor is configured to remove at least a portion of molten metal formed in the electrolytic cell.

10. The system of any one of claims 1-9, wherein the collection vessel is positioned under the cathode and configured to collect molten metal formed on the cathode.

11. The system of any one of claims 1-10, wherein the extractor comprises a ladle.

12. The system of any one of claims 1-11, wherein the electrolyte comprises a molten salt.

13. The system of any one of claims 1-12, wherein the system is configured to extract a metal from a metal containing material.

14. The system of claim 13, wherein the metal comprises a rare earth metal and/or an alkali metal.

15. The system of claims 13 or 14, wherein the metal containing material comprises an anion comprising at least one halogen, oxygen, and/or sulfur.

16. The system of any one of claims 1-15, wherein the system is configured such that, when the system is electrolytically extracting metal and the extractor is being used to remove metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the system, and electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the system.

17. The system of any one of claims 1-16, wherein the system is configured such that, when the system is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte within the container, a maximum current passed between the anode and the cathode is less than or equal to 200% of current passed between the anode and the cathode immediately prior to inserting the extractor.

18. The system of any one of claims 1-17, wherein the extractor is not between the anode and the cathode.

19. The system of any one of claims 1-18, wherein the extractor extends into the container through a top of the container.

20. The system of any one of claims 1-19, wherein, when the extractor is being used to remove metal when the system is electrolytically extracting metal, the metal that is being extracted is electrodeposited onto the extractor at a rate of less than or equal to 3 g of the metal onto the extractor per mAh of charge passed through the system.

21. A method, comprising: removing molten metal that is the product of an electrolytic reaction of an electrolytic cell using an extractor that extends at least partially into the electrolytic cell while simultaneously electrolytically extracting a molten metal from a metal-containing material within the electrolytic cell, wherein the electrolytic cell comprises a cathode, an anode, and an electrolyte, and wherein, when the electrolytic cell is electrolytically extracting metal and the extractor is being used to remove metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the system and electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the system.

22. A method, comprising: removing molten metal that is the product of an electrolytic reaction of an electrolytic cell using an extractor that extends at least partially into the electrolytic cell while simultaneously electrolytically extracting a molten metal from a metal-containing material within the electrolytic cell, wherein the electrolytic cell comprises a cathode, an anode, and an electrolyte, and wherein, when the electrolytic cell is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte, a maximum current passed between the anode and the cathode is less than or equal to 200% of current passed between the anode and the cathode immediately prior to inserting the extractor.

23. The method of any one of claims 21-22, wherein the molten metal is removed without having to remove the cathode and/or disassemble the electrolytic cell.

24. The method of any one of claims 21-23, wherein the molten metal is formed on the cathode during operation of the electrolytic cell.

25. The method of any one of claims 21-24, wherein the molten metal is collected by a collection vessel positioned under the cathode.

26. The method of any one of claims 21-25, wherein removing the molten metal comprises collecting the molten metal using the extractor.

27. The method of any one of claims 21-26, wherein using the extractor comprises inserting the extractor through an opening on a top of the electrolytic cell into a collection vessel, collecting the molten metal from the collection vessel in the extractor, and removing the extractor containing the molten metal from the electrolytic cell.

28. The method of any one of claims 21-27, wherein the electrolytic cell is operated at a temperature of greater than or equal to 300 °C and less than or equal to 1400 °C.

29. The method of any one of claims 21-28, wherein the electrolyte comprises a molten salt.

30. The method of any one of claims 21-29, wherein the electrolyte comprises the metal-containing material.

31. The method of any one of claims 21-30, wherein, when the electrolytic cell is electrolytically extracting metal and the extractor is being used to remove metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the electrolytic cell, and electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the electrolytic cell.

32. The method of any one of claims 21-31, wherein, when the electrolytic cell is extracting metal, within 10 seconds of inserting the extractor into the electrolyte, a maximum current passed between the anode and the cathode is less than or equal to 200% of current passed between the anode and the cathode immediately prior to inserting the extractor into the electrolyte.

33. The method of any one of claims 21-32, further comprising removing metal using the extractor without the extractor being between the anode and the cathode.

34. The method of claim 33, wherein the extractor extends into the electrolytic cell through a top of the electrolytic cell.

35. The method of any one of claims 21-34, wherein, when the extractor is being used to remove metal when the electrolytic cell is electrolytically extracting metal, the metal that is being extracted is electrodeposited onto the extractor at a rate of less than or equal to 3 g of the metal onto the extractor per mAh of charge passed through the electrolytic cell.

36. A method, comprising: removing molten metal that is the product of an electrolytic reaction of an electrolytic cell from the top of the electrolytic cell while simultaneously electrolytically extracting a molten metal from a metal-containing material within the electrolytic cell, wherein the electrolytic cell comprises a cathode, an anode, and an electrolyte.

37. A method, comprising: removing molten metal that is the product of an electrolytic reaction of an electrolytic cell from the electrolytic cell while simultaneously electrolytically extracting a molten metal from a metal-containing material within the electrolytic cell, wherein the electrolytic cell comprises a cathode, an anode, and an electrolyte.

38. The method of any one of claims 36-37, wherein the molten metal is removed without having to remove the cathode and/or disassemble the electrolytic cell.

39. The method of any one of claims 36-38, wherein the molten metal is formed on the cathode during operation of the electrolytic cell.

40. The method of any one of claims 36-39, wherein the molten metal is collected by a collection vessel positioned under the cathode.

41. The method of any one of claims 36-40, wherein removing the molten metal comprises collecting the molten metal using an extractor.

42. The method of claim 41, wherein using the extractor comprises inserting the extractor through an opening on a top of the electrolytic cell into the collection vessel, collecting the molten metal from the collection vessel in the extractor, and removing the extractor containing the molten metal from the electrolytic cell.

43. The method of any one of claims 36-42, wherein the electrolytic cell is operated at a temperature of greater than or equal to 300 °C and less than or equal to 1400 °C.

44. The method of any one of claims 36-43, wherein the electrolyte comprises a molten salt.

45. The method of any one of claims 36-44, wherein the electrolyte comprises the metal-containing material.

46. The method of any one of claims 36-45, wherein, when the electrolytic cell is electrolytically extracting metal and the extractor is being used to remove metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the electrolytic cell, and electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the electrolytic cell.

47. The method of any one of claims 36-46, wherein, when the electrolytic cell is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte, a maximum current passed between the anode and the cathode is less than or equal to 200% of current passed between the anode and the cathode immediately prior to inserting the extractor.

48. The method of any one of claims 36-47, wherein the molten metal is removed using the extractor without the extractor being between the anode and the cathode.

49. The method of any one of claims 36-48, wherein, when the extractor is being used to remove metal when the electrolytic cell is electrolytically extracting metal, the metal that is being extracted is electrodeposited onto the extractor at a rate of less than or equal to 3 g of the metal onto the extractor per mAh of charge passed through the electrolytic cell.

50. An electrolytic cell for metal extraction, comprising: a container; an electrolyte within the container; an anode at least partially within the container; a cathode at least partially within the container; a collection vessel within the container, the collection vessel having an internal surface that faces the cathode; and an extractor at least partially within the container, wherein the internal surface of the collection vessel is accessible from the exterior of the electrolytic cell when the cathode is positioned within the cell and in a configuration in which electrolysis can be performed.

51. The electrolytic cell of claim 50, wherein at least 10% of the lateral extent of an opening of the collection vessel is not covered by the cathode.

52. The electrolytic cell of any one of claims 50-51, further comprising an extractor at least partially contained within the collection vessel, wherein the extractor comprises an opening in fluidic communication with the collection vessel.

53. The electrolytic cell of claim 52, wherein the extractor is configured to remove at least a portion of molten metal formed in the electrolytic cell.

54. The electrolytic cell of any one of claims 50-53, wherein the metal collection vessel is positioned under the cathode and configured to collect molten metal formed on the cathode.

55. The electrolytic cell of any one of claims 52-54, wherein at least a portion of the extractor is disposed within the collection vessel.

56. The electrolytic cell of any one of claims 52-55, wherein the extractor comprises a ladle.

57. The electrolytic cell of any one of claims 50-56, wherein the container has an oval shaped cross-section.

58. The electrolytic cell of claim 57, wherein a cross-section of the cathode is positioned adjacent a first vertex of the oval shaped cross-section of the container.

59. The electrolytic cell of any one of claims 57-58, wherein a cross-section of the extractor is positioned adjacent a second vertex of the oval shaped cross-section of the container.

60. The electrolytic cell of any one of claims 50-59, wherein the electrolyte comprises a molten salt.

61. The electrolytic cell of any one of claims 50-60, wherein the electrolytic cell is configured such that, when the electrolytic cell is electrolytically extracting metal, the extractor corrodes at a rate of less than or equal to 3 g of the extractor per mAh of charge passed through the electrolytic cell, and electrodeposition of material on the extractor proceeds at a rate of less than or equal to 3 g of the material per mAh of charge passed through the electrolytic cell.

62. The electrolytic cell of any one of claims 50-61, wherein, when the electrolytic cell is electrolytically extracting metal, within 10 seconds of inserting the extractor into the electrolyte, a maximum current passed between the anode and the cathode is less than or equal to 200% of current passed between the anode and the cathode immediately prior to inserting the extractor.

63. The electrolytic cell of any one of claims 50-62, wherein the extractor extends into the electrolytic cell through a top of a container of the electrolytic cell.

64. The electrolytic cell of any one of claims 50-62, wherein the electrolytic cell is configured such that, when the extractor is being used to remove metal when the electrolytic cell is electrolytically extracting metal, the metal that is being extracted is electrodeposited onto the extractor at a rate of less than or equal to 3 g of the metal onto the extractor per mAh of charge passed through the electrolytic cell.