Electrowinning of elemental metals from metallic compounds.

Abstract

For example, solutions are disclosed for the recovery of elemental metals on an industrial scale without smelting, including the recovery of near-pure lead from recycled LAB by specialized electrolytic processing. Additionally, novel processes, innovative electrolyzer designs, and / or novel applications of auxiliary chemicals, particularly applicable to the solid-state electrolysis of mixtures containing lead paste, electrolyte, and auxiliary chemicals, required for successful electrolysis of impure forms to pure metal (e.g., lead oxide to pure lead), are disclosed. In particular, with regard to the recovery of near-pure lead during LAB recycling, the electrolytic processing with auxiliary chemicals allows for the solid-state electrolysis of mixtures containing impure lead (e.g., lead paste), and is scalable to an industrial level by utilizing horizontal cathodes in the electrolyzer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Utility Patent Application No. 17 / 737,869, entitled "ELECTROLYTIC EXTRACTION OF ELEMENTAL METAL FROM METAL COMPOUNDS" (Attorney Docket No. AGR2102US1U), filed May 5, 2022, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] Elemental metals such as gold, silver, copper, zinc, and lead can be recovered from materials containing these metals by various electrolytic processes (e.g., electrolysis). For example, with regard to recycling lead-acid batteries (LAB), the lead paste obtained therefrom (which typically contains a fraction of pure lead as well as lead monoxide, lead dioxide, and lead sulfate) can be dissolved or mixed with an electrolyte, and the resulting solution or mixture can then be subjected to electrolytic recovery of pure elemental lead (Pb) at the cathode of an electrolytic device.

[0003] However, while conceptually simple and easy to implement on a small scale, economically recovering lead from battery pastes via electrolysis processes on an industrial scale, in sufficient yield and purity, and in an environmentally friendly manner, as an alternative to existing approaches that require high-temperature smelting, has heretofore been impractical and completely unachievable. Electrode materials for lead recovery are relatively expensive, and the operating conditions at the electrodes tend to promote the formation of undesirable by-products. In existing electrolysis approaches, insoluble lead dioxide frequently forms at the anode, limiting current flow and reducing operating efficiency. Similarly, lead produced at the cathode using acidic electrolytes deposits as a film on the cathode surface, and this lead can be difficult to remove from the cathode. This deposited lead also redissolves in the electrolyte when the current, i.e., the power source that drives the electrolysis, is stopped. Other drawbacks exist as well.

[0004] Thus, there has been a long felt need in the art and industry for a scalable, cost-effective, and environmentally friendly solution to enable the extraction and / or recovery of pure elemental metals from impure sources, such as the recovery of near pure lead (Pb) from recycled LAB. Summary of the Invention [Means for solving the problem]

[0005] This specification discloses systems, methods, processes, and / or chemical compositions for recovering elemental metals on an industrial scale without smelting, including, for example, recovery of near-pure lead from recycled LAB by specialized electrolytic processing. Some various implementations disclosed herein feature new processes, innovative electrolytic device designs, and / or novel utilization of auxiliary chemicals required to successfully electrolyze pure lead from impure forms, and are particularly applicable to solid-state electrolysis of mixtures including lead paste, electrolyte, and said auxiliary chemicals. In particular, with respect to recovering near-pure lead during LAB recycling, the electrolytic processing with auxiliary chemicals allows for solid-state electrolysis of mixtures including impure lead (e.g., lead paste), and is further scalable to industrial levels by utilizing horizontal cathodes in the electrolytic device.

[0006] More specifically, various implementations disclosed herein are directed to electrolysis systems and processes for recovering near-pure metals (e.g., elemental lead) from impure metal materials (e.g., lead oxides) containing a target metal (e.g., lead), the method includes combining the impure metal material with an electrolyte to form a slurry, the slurry being a mixture of the impure metal material and the electrolyte such that the electrolyte does not dissolve the target metal in the impure metal material; performing solid-state electrolysis on the slurry to form a target metal deposit and a residual component; separating the target metal from substantially all of the electrolyte and at least a portion of the residual component; and removing dross to dissolve the target metal deposit and to render the remaining dissolved target metal near-pure without smelting. Some implementations disclosed herein may further include adding at least one auxiliary chemical to the slurry before performing solid-state electrolysis; mechanically separating the dross into component materials for further processing; and / or desulfurizing the impure metal material before combining the impure metal material with the electrolyte to form the slurry. In certain such implementations, the impure metallic material includes a first impure form of the target metal and a second impure form of the target metal, the first impure form being chemically distinct from the second impure form, the impure metallic material includes a third impure form of the target metal, the third impure form being chemically distinct from the first impure form and the second impure form, the target metal formed during solid-state electrolysis is derived from the first impure form, the second impure form, and the third impure form, the at least one auxiliary chemical includes a first auxiliary chemical, a second auxiliary chemical, and a third auxiliary chemical, the first auxiliary chemical enabling solid-state electrolysis of the first impure form, the second auxiliary chemical enabling solid-state electrolysis of the second impure form, and the third auxiliary chemical enabling solid-state electrolysis of the third impure form. The target metal is elemental lead (Pb), and a first impure form is lead monoxide (PbO), a second impure form is lead dioxide (PbO2), and a third impure form is lead hydroxide (Pb(OH)2); and / or the electrolysis is carried out using an electrolysis apparatus including a horizontal cathode against which the slurry is placed for electrolysis.

[0007] Some alternative implementations disclosed herein are directed to a system for recovering near-pure metals from an impure metallic material containing a target metal, the system including at least one subsystem for combining the impure metallic material with an electrolyte to form a slurry, the slurry being a mixture of the impure metallic material and the electrolyte such that the electrolyte does not dissolve the target metal in the impure metallic material; performing solid-state electrolysis on the slurry to form a target metal deposit and a residual component; mechanically separating the target metal from substantially all of the electrolyte and at least a portion of the residual component; and dissolving the target metal deposit and removing dross such that the remaining dissolved target metal is near-pure without smelting. Certain implementations may further include at least one subsystem for one or more of adding at least one auxiliary chemical to the slurry prior to performing solid-state electrolysis; mechanically separating the dross into component materials for further processing; and / or desulfurizing the impure metallic material prior to combining the impure metallic material with the electrolyte to form the slurry. For certain implementations, the impure metallic material includes a first impure form of the target metal and a second impure form of the target metal, the first impure form being chemically distinct from the second impure form; the impure metallic material includes a third impure form of the target metal, the third impure form being chemically distinct from the first impure form and the second impure form; and / or the target metal is elemental lead (Pb), the first impure form is lead monoxide (PbO), the second impure form is lead dioxide (PbO2), and the third impure form is lead hydroxide (Pb(OH)2).

[0008] Further implementations are also directed to an apparatus for recovering near-pure lead from an impure lead paste containing one or more of lead monoxide (PbO), lead dioxide (PbO2), or lead hydroxide (Pb(OH)2), the apparatus comprising: a mixer for combining the impure lead paste with an electrolyte to form a slurry, the slurry being a mixture of the impure lead paste and the electrolyte such that the electrolyte does not dissolve the lead monoxide (PbO), lead dioxide (PbO2), or lead hydroxide (Pb(OH)2) in the lead paste; an electrolysis apparatus for performing solid-state electrolysis on the slurry to form sponge lead and a residual component, the electrolysis apparatus being capable of discharging a portion of the electrolyte when the solid-state electrolysis is completed; a transformer including a press for mechanically separating the sponge lead from substantially all of the remaining electrolyte to produce a lead brick; and a smelter for smelting the lead brick into molten lead and dross, where only near-pure lead remains after the dross is removed. Certain such implementations may further include a desulfurizer that converts lead sulfate (PbSO4) in the lead paste to lead hydroxide (Pb(OH)2) before the mixer forms the slurry. In selected implementations, the mixer may also combine at least one auxiliary chemical with the slurry.

[0009] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter, nor is it an admission that any of the information provided herein is prior art to the implementations described herein.

[0010] The foregoing summary and the following detailed description of exemplary implementations will be better understood when read in conjunction with the appended drawings, in which: For the purpose of illustrating the implementations, there are shown in the drawings exemplary configurations of the implementations; [Brief description of the drawings]

[0011] [Figure 1A] FIG. 1 is a modified block diagram showing the main components of an exemplary end-to-end electrochemical system for recovering near-pure lead from the LAB, representative of various implementations disclosed herein, illustrating the material flow direction between its various subsystems. [Figure 1B] FIG. 1B is a process flow diagram illustrating an exemplary approach for LAB recycling using the system of FIG. 1A, representative of various implementations disclosed herein. [Figure 1C] FIG. 1C is a modified process flow diagram of the process shown in FIG. 1B to further illustrate separation and dross processing of other recyclables representative of various implementations disclosed herein. [Figure 2A] FIG. 1 is a perspective view of a representative electrolysis cell 100 of various implementations disclosed herein. [Figure 2B] 2B is a blown-out perspective view and an internal view of the anode of the electrolysis cell of FIG. 2A representative of various implementations disclosed herein. [Figure 3A] FIG. 2C is a cutaway side view of the electrolysis cell of FIGS. 2A and 2B, representative of various implementations disclosed herein, in an initial ready-to-use configuration for performing electrolysis. [Figure 3B] FIG. 2C is a cutaway side view of the electrolysis cell of FIGS. 2A and 2B, representative of various implementations disclosed herein, after it has been filled with electrolyte for electrolysis. [Figure 3C] 2C is a cutaway side view of the electrolysis cell of FIG. 2A and FIG. 2B, representative of various implementations disclosed herein, after electrolysis has occurred and liquid components have been expelled from the electrolysis compartment. [Figure 3D] FIG. 2C is a cutaway side view of the electrolysis cell of FIGS. 2A and 2B, representative of various implementations disclosed herein, after the end product of electrolysis has been scraped off the horizontal cathode surface and removed from the electrolysis compartment. [Figure 4A] FIG. 2 is a perspective view of a vertical stack of representative electrolysis cells of various implementations disclosed herein. [Figure 4B] FIG. 2 is a perspective view of a horizontal line including multiple stacks of representative electrolysis cells of various implementations disclosed herein. [Figure 4C] FIG. 1 is a perspective view of a parallel array of multiple horizontal lines, each including multiple stacks of electrolysis cells representative of various implementations disclosed herein. [Figure 5A] Annotated chemical diagram of the molecular structures of lead monoxide (PbO), lead dioxide (PbO2), and lead hydroxide (Pb(OH)2) (collectively "lead oxide components" or "lead oxides"). [Figure 5B] For clarity, here is an annotated chemical diagram of the molecular structure of lead sulfate (PbSO4), shown with and without bond charges (i.e., the lead (Pb) atom is juxtaposed with two oxygen atoms that are single-bonded to a sulfur atom). [Figure 6] FIG. 1 is a block diagram of an exemplary computing environment that can be used in conjunction with any of the various implementations and aspects disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Although various implementations disclosed herein are described as being particularly relevant to the recovery of elemental lead from recycled LAB, such implementations may be applied to the recovery of other metals and / or other metal sources as well. Thus, this specification is not intended to limit such implementations to lead or LAB recycling, but instead, the disclosure herein should be construed as broadly as possible as it applies to a variety of different metals extracted or recovered from a variety of potentially different sources.

[0013] This specification discloses systems, processes, and chemical compositions for recovering elemental metals on an industrial scale without smelting, and in particular, systems, processes, and chemical compositions for recovering elemental lead from recycled LAB by electrolytic processing. Although various implementations disclosed herein are described with particular reference to the recovery of elemental lead from recycled LAB, such implementations may be applied to the recovery of other metals and / or other metal sources as well. Thus, this specification is not intended to limit such implementations to lead or LAB recycling, but instead, the disclosure herein should be construed as broadly as possible as it applies to a variety of different metals extracted or recovered from a variety of potentially different sources.

[0014] Understanding various concepts helps to understand the various implementations disclosed herein more broadly and more completely, and those skilled in the art will readily appreciate the impact of these various concepts on the breadth and depth of the various implementations disclosed herein. Certain terms used herein may be used interchangeably with other terms used herein, and such terms should be interpreted as broadly as possible unless expressly stated otherwise. For example, as used herein, the terms electrolysis, electrowinning, and electrosmelting should be treated as interchangeable terms, and where one term is used, the other term is implied, so that the use of the term electrolysis should be understood to include electrowinning and electrosmelting, unless expressly distinguished. On the other hand, the term "electrolysis process" is expressly intended to include and encompass electrolysis, electrowinning, and electrosmelting.

[0015] Furthermore, as will be readily understood and well known to those skilled in the art, substances that can be represented by their chemical composition normally using subscript numbers, such as gaseous oxygen (O2), water (H2O), etc., may be represented herein without the subscript numbers (i.e., O2 for gaseous oxygen, H2O for water, etc.) and instead by regular numbers, which are the same and equivalent as when the subscript numbers are used, and no distinction should be made anywhere herein between the use of regular numbers and the use of subscript numbers.

[0016] <Electrolytic process>

[0017] As is well known and readily understood by those skilled in the art, electrolysis is a technique that uses direct current (DC) to drive non-spontaneous chemical reactions. By using an electrolytic cell, electrolysis can be used to separate elements from one another. More specifically, in the electrolysis process, an electric current, specifically a direct current (DC), is passed through an electrolyte, causing a chemical reaction at the electrodes and decomposing materials within the electrolyte.

[0018] The main components required to achieve electrolysis are an electrolyte, electrodes, and an external power source. An electrolyte is a chemical that contains free and mobile ions and can conduct electric current. An electrolyte can be an ion-conducting polymer, a solution, or an ionic liquid compound. For example, liquid electrolytes are created by "solvation," i.e., the attraction or association of the ions of the solute with the solvent (such as water), creating mobile clusters of ions and solvent molecules.

[0019] To achieve electrolysis, electrodes (suitably connected to a power source) are immersed in an electrolyte, but separated from one another by a sufficient distance so that current flows between the electrodes through the electrolyte, completing an electrical circuit. In this configuration, a direct current provided by the power source attracts ions toward each oppositely charged electrode, driving a non-spontaneous reaction.

[0020] Each electrode attracts ions of the opposite charge. Positively charged ions ("cations") migrate toward the negatively charged cathode where they supply electrons, and negatively charged ions ("anions") migrate toward the positively charged anode where they extract electrons. In effect, electrons are introduced at the cathode (as reactants) and removed at the anode (as the desired end product). The loss of electrons is called oxidation, and the gain of electrons is called reduction.

[0021] The cathode may be made of the same material as the anode, but is usually made of a more reactive material since wear at the anode is higher due to oxidation at the anode. The anode may be made of the same material as the cathode, but is often made of a less reactive material than the cathode, since wear at the anode is typically higher than wear at the cathode due to oxidation that occurs at the anode during electrolysis.

[0022] When neutral atoms or molecules gain or lose electrons (such as those at the surface of an electrode), they become ions, which dissolve in the electrolyte and react with other ions. Conversely, when ions gain or lose electrons to become neutral, they form compounds that separate from the electrolyte; for example, positive metal ions deposit on the cathode in layers. Furthermore, if ions gain or lose electrons without becoming neutral, they still change electronic charge in the process.

[0023] The key process of electrolysis is the exchange of atoms and ions through the addition or removal of electrons resulting from an applied direct current to produce a desired end product (or, in some cases, multiple end products). The desired end products of electrolysis are often in a different physical state than the electrolyte and can be removed by any of several different physical processes, for example, by collecting the gaseous end products from above the electrodes, by electrodepositing dissolved end products from the electrolyte, or by removing (e.g., scraping) solid end products that have accumulated at one of the electrodes.

[0024] While the decomposition potential of an electrolyte is the voltage required for electrolysis to occur, the amount of end product obtained from electrolysis is proportional to the current applied, and Faraday's law of electrolysis states that when two or more electrolytic cells are connected in series to the same power source, the end products produced in the cells are proportional to their equivalent weights.

[0025] <Solid electrolysis>

[0026] In "solid-state electrolysis," a solid metal compound or mixture of metal compounds ("active materials") can be reduced via electrolysis to a pure metal end product by directly contacting the active materials with the cathode of an electrolytic cell. However, placing (e.g., "pasting") the active materials onto the cathode surface can be difficult because the various active materials do not naturally adhere to each other.

[0027] Typically, the active material is pasted directly onto the cathode by removing the cathode from the electrolyte in the electrolytic cell and applying a mixture of the active material and electrolyte onto the cathode surface. After the mixture is dried on the cathode, the cathode is then suspended again in the electrolyte of the electrolytic cell. However, in industrial-scale operations, pasting the active material onto the cathode surface is time-consuming and expensive, due in part to the size of the electrodes required for such pasting. Furthermore, during electrolysis, the dry-pasted active material on the cathode may absorb moisture from the electrolyte in the electrolytic cell, causing the pasted material to peel off or slide off the cathode, resulting in water-type electrolysis of this absorbed moisture, which together may effectively replace and / or hinder the desired electrolysis reaction of the active material. Furthermore, it is natural for a small amount of the resulting end product to accumulate and adhere to the cathode itself, and removing this end product from the cathode may be time-consuming, inefficient, and expensive.

[0028] Due to these inherent drawbacks, solid state electrolysis has not been utilized to commercially process active materials on an industrial scale, with such industries instead choosing more traditional approaches to purify active materials into desired end products, such as smelting, etc. However, as is well known and widely understood by those skilled in the art, smelting has its own drawbacks, and therefore there remains a need for alternative refining processes and machinery to perform the same on an industrial scale.

[0029] <Recycling lead-acid batteries>

[0030] Lead-acid batteries (LAB) are now widely used and, unlike other types of batteries, are almost completely recyclable, making them the single most recycled item today. Lead recycling is economically important because, while LAB production continues to increase year on year worldwide, the production of new lead is becoming increasingly difficult due to the depletion of lead-rich deposits. However, currently, almost all recycling of lead from LAB on an industrial scale is based on smelting, a pyrometallurgical process in which lead, lead oxides (e.g., PbO and PbO2), and other lead compounds are heated to approximately 1600°F to 2200°F (900°C to 1200°C) and then mixed with various reducing agents to remove oxygen, sulfates, and other non-lead materials.

[0031] Unfortunately, lead smelting is highly polluting because it generates large amounts of airborne waste (e.g., lead dust, arsenic, carbon dioxide, and sulfur dioxide), solid waste (e.g., slag containing toxic compounds of lead and other heavy metals), and liquid waste (e.g., sulfuric acid, arsenic, and other heavy metals and their oxides). In fact, the pollution generated from smelting is so high that many smelters in the United States and other Western countries have been forced to close to protect the environment. The relocation or expansion of smelting to less regulated countries has resulted in large-scale pollution and high levels of human lead exposure in those countries, but it is expected that similar reduction measures will be taken in those countries as time goes on and new technologies become available.

[0032] There are many approaches known in the art for recycling lead from LAB, but they all suffer from one or more drawbacks that make them impractical. Therefore, there remains a need for improved equipment and methods for scalable, smelter-free LAB recycling that can maximize lead recovery while minimizing environmental impact and excessive costs. Also, several efforts have been made to move away from smelting operations and use more environmentally friendly solutions, but so far they have all been unsatisfactory for a variety of reasons, ranging from various pollution issues, to low yields and profitability, to lab-type solutions that cannot be scaled up effectively or efficiently.

[0033] <Electrolytic process>

[0034] As briefly described herein above, elemental metals such as gold, silver, copper, zinc, and lead can be recovered from materials containing these metals by various electrolytic processes (e.g., electrolysis). For example, with respect to recycling lead-acid batteries (LAB), the lead paste obtained therefrom (which typically contains a portion of pure lead as well as lead monoxide, lead dioxide, and lead sulfate) can be dissolved or mixed in an electrolyte, and the resulting solution or mixture can then be subjected to electrolytic recovery of pure elemental lead (Pb) at the cathode of an electrolytic device.

[0035] However, while conceptually simple and easy to implement on a small scale, economically recovering lead from battery pastes via electrolysis processes on an industrial scale, in sufficient yield and purity, and in an environmentally friendly manner, as an alternative to existing approaches that require high-temperature smelting, has heretofore been impractical and completely unachievable. Electrode materials for lead recovery are relatively expensive, and the operating conditions at the electrodes tend to promote the formation of undesirable by-products. In existing electrolysis approaches, insoluble lead dioxide frequently forms at the anode, limiting current flow and reducing operating efficiency. Similarly, lead produced at the cathode using an acid electrolyte deposits as a film on the cathode surface, and this lead can be difficult to remove from the cathode. This deposited lead also redissolves in the electrolyte when the current, i.e., the power source that drives the electrolysis, is stopped. Other drawbacks exist as well.

[0036] Thus, there has been a long felt need in the art and industry for a scalable, cost-effective, and environmentally friendly solution to enable extraction and / or recovery of pure elemental metals from impure sources, such as, for example, recovery of near-pure lead (Pb) during LAB recycling.

[0037] As used herein (both hereafter and hereafter), the term "near pure" shall mean a purity comparable to within 90% of the average purity obtained by conventional smelting processes. Similarly, the term "pure" shall mean a purity equal to or exceeding the typical purity level obtained by conventional smelting processes, and the term "perfect purity" shall mean a purity in which the elemental metal is 99.000%, regardless of natural surface oxidation or hydroxide. Thus, for all implementations for obtaining "near pure" metals disclosed herein, such disclosures should be considered to also disclose alternative implementations for obtaining "pure" and "perfectly pure" metals. Also, as used herein, the term "recovery" and other equivalent terms (e.g., refining, derivatization, etc.) shall refer to obtaining a higher purity metal (e.g., elemental lead) from a less pure form of the metal (e.g., lead oxide) via electrolysis or other electrolytic processes.

[0038] FIG. 1A is a modified block diagram 10 illustrating the major components of an exemplary end-to-end electrochemical system for recovering near-pure lead from the LAB, showing the material flow direction between its various subsystems, and is representative of various implementations disclosed herein.

[0039] In FIG. 1A, the LAB to be cycled is fed by a LAB source 12 (shown as a dotted line to indicate an input or output for the system) to a LAB breaker 14 where the LAB is physically reduced and split into five main components: battery acid (if present), plastic, metal, separator, and lead paste. The battery acid, typically sulfuric acid (H2SO4), is then output to an acid neutralizer 16 for further processing, although this operation may not be necessary (and therefore optional) if the battery acid has already been removed from the LAB provided by the LAB source 12 or if no acid is present. The LAB breaker may also include a plastic washer 40 to remove lead residue (usually lead monoxide) from the surface of the plastic before outputting the lead-free (or near-lead-free) plastic to a plastic recycler 18.

[0040] Metals crushed by the LAB breaker 14 are sent to a metal reclaimer 20 for recovery of their lead content (typically pure lead (Pb)), which is conveyed to a smelter 32 (described below), and the remaining non-lead metals are appropriately output (e.g., disposed of or further recycled). Similarly, separators crushed by the LAB breaker 14 are conveyed to a separator cleaner 22 for recovery of residual lead, which, together with lead paste resulting from LAB crushing by the LAB breaker 14 (directly and / or from the plastic washer 40), are conveyed to a lead paste desulfurizer 24, and the remaining non-lead separator content is output to a separator reclaimer 46.

[0041] The lead received by the lead paste desulfurizer 24 directly from the crushing of LAB in the LAB breaker 14, from its plastic washer 40, and / or from the separator cleaner 22 typically contains elemental lead (Pb), lead monoxide (PbO), and lead dioxide (PbO2), as well as lead sulfate (PbSO4). The lead paste desulfurizer 24 processes the lead paste to remove sulfur from the lead sulfate (PbSO4), which is a highly harmful environmental pollutant. This desulfurization can be accomplished by introducing sodium hydroxide (NaOH) into the lead paste to chemically convert the lead sulfate (PbSO4) to lead hydroxide (Pb(OH)2) and the sodium hydroxide (NaOH) to sodium sulfate (Na2SO4), which is then removed from the paste by the lead paste desulfurizer 24 utilizing any of a variety of means well known and understood by those skilled in the art. Additionally, barium sulfate (BaSO4) may be added to the lead paste as an additive prior to or during the desulfurization process, where the barium sulfate does not react with sodium hydroxide (NaOH) during desulfurization and is intentionally retained in the resulting (otherwise "desulfurized") lead paste with the expectation that it will be removed later by a subsequent subsystem. Thus, the desulfurization achieved by the lead paste desulfurizer 24 intentionally removes only sulfur from the lead sulfate (PbSO4). In either case, the desulfurized lead paste (now containing only metallic lead in the form of elemental lead (Pb), lead monoxide (PbO), lead dioxide (PbO2), and lead hydroxide (Pb(OH)2)) is then sent to the slurry mixer 26 where the desulfurized lead paste is combined with electrolyte 42 and auxiliary chemicals 44 (described in more detail later herein) to form a lead slurry solution or mixture.

[0042] In particular, in certain alternative implementations of system 10, plastics, metals, separators, and lead paste may be provided to system 10 directly and / or separately in already crushed form by one or more input sources (not shown) instead of LAB source 12, in which case such inputs may bypass LAB breaker 14 and proceed to other appropriate subsystems, as appropriate. Similarly, in certain other alternative implementations, lead paste may instead be fed directly to the system, i.e., to lead paste desulfurizer 24 if it has not yet been desulfurized, or to slurry mixer 26 if it has already been desulfurized (specifically with respect to lead sulfate (PbSO4), but not with respect to barium sulfate (BaSO4), as explained above).

[0043] In the slurry mixer 26, and in some such implementations disclosed herein, sodium hydroxide (NaOH) may be used as an electrolyte for subsequent electrolytic processing (e.g., electrolysis) of the lead paste, in which case the resulting lead slurry is a mixture of desulfurized lead paste and electrolyte (not a solution thereof in the chemical sense). The lead slurry is then transferred from the slurry mixer 26 to the electrolyzer 28 for electrolytic processing (described in more detail later herein). The electrolyzer 28 operates to produce substantially deoxidized elemental lead (Pb) from the lead monoxide (PbO), lead dioxide (PbO2), and lead hydroxide (Pb(OH)2) contained in the lead slurry.

[0044] In certain other alternative implementations of the system 10, instead of desulfurizing the impure metallic material prior to combining it with the electrolyte to form a slurry, the sulfur-containing impure metallic material may be combined with the electrolyte to form a sulfur-containing slurry, and the electrolyzer itself may be utilized to desulfurize the impure metallic material prior to or during the aforementioned electrolysis. For example, this additional functionality of the electrolyzer may be accomplished by consuming the stoichiometric caustic contained in the electrolyte and in situ producing sodium sulfate that can be separated from the resulting deoxidized lead in subsequent processing.

[0045] In either case, the resulting deoxidized lead can then be transferred to the transformer 30 for conversion into solid bricks with minimal amounts of electrolyte and / or auxiliary chemicals. In the case of a lead slurry mixture (not a solution), much of the electrolyte and / or auxiliary chemicals may be removed by the electrolyzer 28 before being transferred to the transformer 30, and / or the transformer can include physically compressing the deoxidized lead into solid bricks, said compression also being effective in removing much of the residual electrolyte and / or auxiliary chemicals. On the other hand, in the case of a lead slurry solution, the transformer 30 may instead precipitate the deoxidized lead, thereby separating it from the electrolyte and auxiliary chemicals, and then compressing it into bricks.

[0046] The lead bricks, which may still contain traces of electrolytes, auxiliary chemicals, and other impurities, including but not limited to barium sulfate (BaSO4), lead oxides (lead monoxide, lead dioxide, and / or lead hydroxide), as well as new natural oxidation occurring on the surface of the bricks, are then sent to the melter / caster 32 where they are melted, the dross is removed, and cast as an output ingot of near-pure lead 48. This melting and casting may also include as an input lead reclaimed by the metal reclaimer 20 previously described herein. Meanwhile, the dross is sent to a mechanical separator 34 where it is separated into elemental lead (Pb) for later return to the melter / caster 32, and lead monoxide (PbO) for return to the slurry mixer 26 for inclusion in the next lead slurry mixture for further processing. In certain implementations, the barium sulfate (BaSO4), electrolytes, and auxiliary chemicals (and their residues) are recovered and / or reused at various points in the system (not shown).

[0047] Figure IB is a process flow diagram 60 illustrating an exemplary approach for LAB recycling using the system of Figure 1A representative of various implementations disclosed herein. In Figure IB, LAB received for recycling at 62 are crushed to produce lead paste and other recyclables, the latter of which can be separately processed at 64 as generally described herein above with respect to Figure 1A. Additional lead recovered from this separation process is returned and combined with the lead paste obtained directly from crushing at 62.

[0048] At 66, the lead paste obtained at 62 (and 64, if present) is then desulfurized, such as by treatment with sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH4OH) or aqueous ammonia, or other suitable chemicals, such that the resulting desulfurized lead paste contains substantially sulfur-free lead components (e.g., Pb, PbO, PbO2, and Pb(OH)2), but does not contain lead sulfate (PbSO4). At 68, the desulfurized lead paste may be combined with electrolytes and auxiliary chemicals to form a slurry mixture (or, in an alternative implementation, a slurry solution). At 70, this slurry may be introduced into an electrolytic cell to perform solid-state electrolysis (or, in an alternative implementation, general solution-based electrolysis) at 72.

[0049] Once electrolysis is complete, the liquid components (which may include auxiliary chemicals or their residues) are drained first at 74, and the remaining solid components resulting from electrolysis (which may be in the form of a "sponge lead" solid permeated with the residual liquid components) are also removed at 76, or in alternative implementations, the liquid and solid components may be simultaneously removed from the electrolysis device. At 78, the "sponge lead" solid component (now containing substantially pure lead (Pb)) may be compressed to remove substantially all of the remaining liquid components ("residues") and form a substantially pure lead brick. At 80, the lead brick may be melted to remove substantially all of the remaining trace non-lead components and other trace impurities, said melting being carried out (at temperatures much lower than those required for smelting) to further refine the lead brick and form a near pure lead ingot for output.

[0050] In particular, elements 70-76 of Figure 1B (shown in the figure as electrolytic process group 82) are carried out using various implementations of electrolytic cells described in more detail below, but this specification does not limit the use of such implementations to only lead recycling or this portion of the lead recycling process, and on the contrary, other additional uses of such implementations are also anticipated by such implementations. For example, various implementations disclosed herein can be used to further process dross removed during dissolution 80, including, but not limited to, the process described with respect to Figure 1A above.

[0051] FIG. 1C is a modified process flow diagram 60′ of the process 60 shown in FIG. 1B, illustrating in further detail the separation and dross processing 92 of other recyclables 64 representative of various implementations disclosed herein. In FIG. 1C, the battery acid, typically sulfuric acid (H2SO4), is neutralized at 84 and output from the system. At 86, the plastic is washed and the lead residue (typically lead monoxide) recovered from the surface of the plastic is combined with lead paste for desulfurization and output from the system. Similarly, at 88, the separator is washed and the lead residue (typically lead monoxide) recovered from the surface of the plastic is combined with lead paste for desulfurization and output from the system. Also, at 90, the metal is washed (or “reclaimed”) and the lead-free metal is output (discarded or recycled) and its lead content (usually pure lead (Pb)) is conveyed directly to a melter for melting at 80. However, it should be noted that metals recovered from the LAB often contain both lead (Pb) and antimony (Sb) as an alloy, i.e., lead antimony (or antimony lead). In this case, it is not necessary to separate the lead and antimony, and therefore certain alternative implementations may instead output lead antimony from the reclaimer 90 for melting at 80 to form near-pure antimony lead instead of near-pure elemental lead (Pb).

[0052] FIG. 1C also shows how the dross resulting from the melting at 80 is mechanically separated at 92, with lead monoxide (PbO) resulting from the mechanical separation being added to a subsequent batch of lead paste that is desulfurized at 68 for reprocessing, while elemental lead (Pb) resulting from the mechanical separation being returned to the subsequent batch of sponge lead that is melted at 80.

[0053] <Electrolytic cell with horizontal cathode>

[0054] Disclosed herein is an electrolysis cell that includes a horizontal cathode above which a horizontal anode is suspended. The horizontal cathode may form the base of an electrolysis compartment in which a mixture of active material and electrolyte, for example in the form of a slurry, is introduced, held and processed. The horizontal anode is suspended above the cathode at the top of the electrolysis compartment such that the anode physically engages the top surface of the mixture of active material and electrolyte held in the electrolysis compartment, while the cathode naturally engages the bottom surface of the mixture of active material held in the electrolysis compartment. The anode may also be provided with small openings (sometimes simply referred to herein as "breathing holes") in the form of vents, grooves, holes, etc. across its surface to allow gaseous oxygen (O2) and / or other gaseous substances produced by electrolysis to escape harmlessly (instead of being trapped under said anode and creating a resistance to current flow).

[0055] Accordingly, various implementations disclosed herein are directed to and / or may utilize electrolysis devices that include a horizontal cathode disposed beneath a suspended anode for the purpose of performing electrolysis on a metal-containing mixture or solution. In some such implementations, the horizontal cathode may include a bottom surface of a compartment for containing a mixture or solution of metal components, electrolyte, and / or auxiliary chemicals; a horizontal anode for engaging a top surface of the mixture or solution within the compartment; a gate corresponding to one sidewall of the compartment for facilitating removal of the end product from the mixture or solution; and / or a removal mechanism for facilitating removal of the end product of the mixture or solution from the compartment (and the surface of the horizontal cathode) through the gate. While certain implementations disclosed herein are specifically directed to use in recycling lead-acid batteries (LAB) without smelting, this specification is not intended to limit the various implementations to only LAB recycling or lead recovery, and instead, the various implementations disclosed herein may be applied to a variety of different electrolyses.

[0056] In various of these implementations, in combination with the use of additional auxiliary chemicals (described further below) added to the active material / electrolyte slurry mixture, a direct current can be passed from the cathode to the anode through the active material / electrolyte mixture to produce a desired end product that can be precipitated on the surface of the cathode. (In certain such implementations, the end product can be pure lead in a sponge form that retains some of the electrolyte and / or auxiliary chemicals.) More specifically, the direct current effectively reduces the metal ions in the active material and separates them from their counterions (such as oxide ions and hydrogen ions that can form water (H2O) and gaseous oxygen (O2)), and the metals in pure form are attracted and precipitated onto the horizontal cathode surface, facilitated in part by gravity (metals are heavier than other components in the slurry) and the natural ionic convection that occurs within the mixture during electrolysis.

[0057] Once electrolysis is complete, in some implementations disclosed herein, the electrolysis compartment may further comprise an openable side for removing electrolyte (including auxiliary chemicals and additional HO produced during electrolysis) and metals of the final product. Initially, this openable side is only partially open, allowing the majority of the pure liquid components, i.e., remaining electrolyte, auxiliary chemicals, and additional water (HO) produced during electrolysis, to initially drain from the electrolysis compartment, and in certain implementations, via a small flow channel at the bottom of the openable side. In some implementations, after the liquid components have drained from the openable side of the electrolysis compartment, this flow channel may be moved to a storage position (e.g., below the electrolysis compartment) away from the openable side.

[0058] After the liquid components are drained, or in an alternative implementation, without first draining the liquid components separately, the openable side can be fully opened to physically remove the more solid components from the electrolysis compartment, i.e. the residual liquid components adhering to the metal of the final product. In selected implementations, the removal is performed by a vertical scraping mechanism that extends across the width of the electrolysis compartment and starts from the opposite side of the openable side, said scraping part physically contacting and gently scraping the entire cathodic face and adjacent sides of the electrolysis compartment, but operating just below (without physically contacting) the anodic face. In this way, the scraping mechanism can push the more solid components out of the electrolysis compartment and into a collection container or a transport mechanism (e.g., a conveyor belt) for further processing.

[0059] In this manner, various implementations disclosed herein can overcome the shortcomings of existing approaches to solid-state electrolysis as described above, namely: (1) time and labor are saved since there is no need to dry-paste active material onto the cathode; (2) the accumulation of water absorbed by the dry-pasted active material during electrolysis and the resulting interference with the production of the desired end product can be completely avoided; and / or (3) the removal of end product accumulation at the cathode is easier since the flat surface of the cathode (as described above) facilitates the scraping action and the auxiliary chemicals help to prevent the end product from solidifying or sticking to the cathode.

[0060] Furthermore, in various implementations disclosed herein, multiple electrolytic cells of the type described herein can be stacked vertically with appropriate spacing between each electrolytic cell and can share a single vertical drop space for final products extruded from the multiple electrolytic cells into a single collection vessel or a single transport mechanism. Additionally, several vertical stacks containing multiple electrolytic cells can be arranged in a row and can share a single elongated collection vessel or a single elongated transport mechanism. Additionally, multiple rows of vertical stacks can be arranged to consolidate the generated final products for continued processing.

[0061] Notably, apart from those disclosed herein, applicants have discovered that achieving the electrolytic effect described herein depends on the utilization of certain chemicals that are mixed into the slurry along with the electrolyte and active material. This application is not directed to the composition of any of these discovered chemicals, but the various implementations disclosed herein are in no way limited to the use of any particular chemical additives, whether secret or proprietary (or, for that matter, widely used and well known).

[0062] Figure 2A is a perspective view of an electrolysis cell 100 representative of various implementations disclosed herein. Figure 2B is a blown-out perspective view and an internal view of an anode 110 of the electrolysis cell 100 of Figure 2A, representative of various implementations disclosed herein. For convenience, Figures 2A and 2B may be collectively referred to herein as Figure 2.

[0063] 2, the electrolysis cell 100 can include an anode 110 suspended above a horizontal cathode 120 at a distance suitable for conducting electrolysis. The electrolysis cell 100 can also include a vertical containment surface 122 and at least one gate 124, which together with the horizontal cathode 120 form and provide an electrolysis compartment 126 that can introduce, hold, and process a mixture of active material and electrolyte, for example in the form of a slurry. The vertical containment surface 122 and the gate 124, or at least their internal surfaces relative to the contents of the electrolysis compartment 126, can be non-conductive.

[0064] As shown, the anode 110 may be configured as a horizontal anode, although other forms of anodes may be utilized, such as, for example, a series of anode rods, strips, grids, or other structures that may physically engage the top surface of the electrolytic slurry placed on the cathode. In any event, the anode 110 may be suspended above the cathode 120 at the top of the electrolysis compartment 126 such that the anode physically engages the top surface of the active material and electrolyte mixture held in the electrolysis compartment, while the cathode naturally engages the bottom surface of the active material mixture held in the electrolysis compartment. In implementations featuring a horizontal anode, the anode 110 may include small openings or vents 114 (i.e., "breathing holes") across its surface to allow gaseous oxygen (O2) produced by electrolysis to harmlessly escape (instead of accumulating under the anode). The anode 110 may also include an opening 112 through which an electrolytic slurry may be disposed within the electrolysis compartment and onto the horizontal cathode 120 in a quantity sufficient for the upper surface of said electrolytic slurry to simultaneously physically engage the suspended anode 110, thereby completing a circuit for electrical current to flow between the cathode 120 and the anode 110 for purposes of electrolysis.

[0065] The electrolysis cell 100 can further include a removal mechanism 160. In various implementations, the removal mechanism 160 can include a vertical surface that extends across the width of the electrolysis compartment 126, beginning opposite the gate 124, and that can physically contact and gently scrape the entire surface of the cathode 120 and the adjacent sides of the electrolysis compartment 126, and can operate below the surface of the anode 110. The removal mechanism, or at least the portion thereof that is exposed to the contents of the electrolysis compartment 126, can be non-conductive.

[0066] FIG 3A is a cutaway side view of the electrolysis cell 100 of FIGS. 2A and 2B in an initial ready-to-use configuration for performing electrolysis, representative of various implementations disclosed herein. As shown in FIG 3A, the electrolysis compartment 126 is empty but ready to be filled, the removal mechanism 160 is in a set position, and the gate 124 is closed. In this configuration, electrolysis slurry can then be deposited into the electrolysis compartment 126 and onto the horizontal cathode 120 via the slurry line 144 that passes through the opening 112 in the anode 110. Also shown in FIG 3A is a conveyor belt 170 with a receiving side 172 and positioned below the gate 124 as a transport mechanism for use in removing the contents of the electrolysis compartment 126 after electrolysis is completed.

[0067] 2A and 2B (as well as FIG. 3A ), representative of various implementations disclosed herein, after being filled with electrolyte 150 for electrolysis. As shown in FIG. 3B , electrolyte 150 includes a mixture of active material 130 and electrolyte 140 and auxiliary chemicals interspersed therein. A bottom surface of electrolyte 150 physically engages (i.e., physically contacts) with horizontal cathode 120, while a top surface of electrolyte (specifically, its electrolytic components) physically engages with anode 110. (In various implementations, the electrolyte contains enough electrolyte to form a top surface of the electrolyte to prevent solid material contact between the cathode and anode, which would create an electrical short and prevent the cathode plate from reducing lead ions from the compound.) Electric current can then be passed through the electrolyte 150 via the anode 110 and cathode 120, and the mobile ions in the electrolyte 140 complete an electrical circuit, causing electrolysis in said electrolyte 150 in response.

[0068] 3C is a cutaway side view of the electrolysis cell 100 of FIGS. 2A and 2B (and FIGS. 3A and 3B), representative of various implementations disclosed herein, after electrolysis has taken place and the liquid component 142 has been discharged from the electrolysis compartment 126 by opening the gate 124 to a first position to provide sufficient space for the liquid component to pass from the electrolysis compartment 126 to the conveyor belt 170 for collection. Meanwhile, the desired end product 132 of the electrolysis remains on the horizontal cathode 120, waiting to be removed from the electrolysis compartment 126.

[0069] 3D is a cutaway side view of the electrolysis cell 100 of FIGS. 2A and 2B (as well as FIGS. 3A, 3B, and 3C), representative of various implementations disclosed herein, after the electrolysis-produced final product 132 has been removed from the horizontal cathode 120 surface and the electrolysis compartment. As shown in FIG. 3D, the gate 124 has been moved to a second fully open position, the removal mechanism 160 has traversed the interior of the electrolysis cell 100, and the final product 132 has been removed from the electrolysis cell 100 onto the conveyor belt 170. As shown, with the removal mechanism 160 in this deployed position and the gate 124 fully open, the empty interior of the electrolysis cell 128 is no longer the electrolysis compartment 126, but once the removal mechanism 160 has returned to its original position (e.g., as shown in FIG. 3A) and the gate 124 has been closed, it again becomes the electrolysis compartment 126. For convenience, FIGS. 3A, 3B, 3C, and 3D may be collectively referred to herein as FIG. 3.

[0070] 4A is a perspective view of a vertical stack 102 of electrolysis cells 100 representative of various implementations disclosed herein. As shown in FIG. 4A, multiple electrolysis cells 100 can be arranged vertically on a single conveyor belt 170 (further distinguished in the drawing by block movement arrows) to increase overall capacity, minimize floor space (or footprint), and increase utilization of the conveyor belt 170 (and minimize expansion of the conveyor belt 170).

[0071] 4B is a perspective view of a horizontal line 104 including multiple vertical stacks 102 of electrolysis cells 100 representative of various implementations disclosed herein. As shown in FIG. 4B, multiple stacks can be arranged linearly on a single conveyor belt 170 to further increase overall capacity while further increasing utilization of the conveyor belt 170 (and minimizing expansion of the conveyor belt 170) versus requiring a separate conveyor belt for each stack 102. Additionally, in certain implementations, multiple stacks 102 can be arranged on either side of the conveyor belt 170 to form a double line (not shown).

[0072] 4C is a perspective view of a parallel array 106 of multiple lateral lines 104, each including multiple stacks 102 of electrolysis cells 100 representative of various implementations disclosed herein. As shown in FIG. 4C, the multiple lateral lines 104 and their corresponding conveyor belts can be arranged to form a three-dimensional array 106 of electrolysis cells that feed into a unified cross-conveyor belt 176. Furthermore, in certain implementations, the conveyor belts 170 from the multiple lines 104 can be directed on either side of the cross-conveyor belt 176 to form a double array (not shown). Furthermore, the particular height, length, and width of such parallel arrays 106 can be configured to optimally fit into nearly any three-dimensional space, although alternative or additional conveyor belt configurations may be required.

[0073] Accordingly, various implementations disclosed herein are directed to electrolysis systems and processes for recovering near-pure metals (e.g., elemental lead) from impure metal materials (e.g., lead oxides, or any other lead compounds) containing a target metal (e.g., lead), the method includes combining the impure metal material with an electrolyte to form a slurry, the slurry being a mixture of the impure metal material and the electrolyte such that the electrolyte does not dissolve the target metal in the impure metal material; performing solid-state electrolysis on the slurry to form a target metal deposit and a residual component; separating the target metal from substantially all of the electrolyte and at least some of the residual component; and removing dross to dissolve the target metal deposit and to render the remaining dissolved target metal near-pure without smelting. Some implementations disclosed herein further include one or more of adding at least one auxiliary chemical to the slurry before performing solid-state electrolysis; mechanically separating the dross into component materials for further processing; and / or desulfurizing the impure metal material before combining the impure metal material with the electrolyte to form the slurry. In certain such implementations, the impure metallic material includes a first impure form of the target metal and a second impure form of the target metal, the first impure form being chemically distinct from the second impure form; the impure metallic material includes a third impure form of the target metal, the third impure form being chemically distinct from the first impure form and the second impure form; the target metal formed during solid-state electrolysis is extracted from the first impure form, the second impure form, and the third impure form; the at least one auxiliary chemical includes a first auxiliary chemical, a second auxiliary chemical, and a third auxiliary chemical, the first auxiliary chemical enabling solid-state electrolysis of the first impure form, the second auxiliary chemical enabling solid-state electrolysis of the second impure form, and the third auxiliary chemical enabling solid-state electrolysis of the third impure form. The target metal is elemental lead (Pb), a first impure form is lead monoxide (PbO), a second impure form is lead dioxide (PbO2), and a third impure form is lead hydroxide (Pb(OH)2); and / or the electrolysis is carried out using an electrolysis apparatus including a horizontal cathode against which the slurry is placed for electrolysis.In selected alternative implementations, the first, second, and / or third impure forms may be any other compound of lead other than oxide.

[0074] Some alternative implementations disclosed herein are directed to a system for recovering near-pure metals from an impure metal material containing a target metal, the system including at least one subsystem for combining the impure metal material with an electrolyte to form a slurry, the slurry being a mixture of the impure metal material and the electrolyte such that the electrolyte does not dissolve the target metal in the impure metal material; performing solid-state electrolysis on the slurry to form a target metal deposit and a residual component; mechanically separating the target metal from substantially all of the electrolyte and at least some of the residual component; and removing dross such that the target metal deposit is dissolved and the remaining dissolved target metal is near-pure without smelting. Certain implementations further include at least one subsystem for one or more of adding at least one auxiliary chemical to the slurry prior to performing solid-state electrolysis; mechanically separating the dross into component materials for further processing; and / or desulfurizing the impure metal material prior to combining the impure metal material with the electrolyte to form a slurry. For certain implementations: the impure metallic material includes a first impure form of the target metal and a second impure form of the target metal, the first impure form being chemically distinct from the second impure form; the impure metallic material includes a third impure form of the target metal, the third impure form being chemically distinct from the first impure form and the second impure form; and / or the target metal is elemental lead (Pb), the first impure form being lead monoxide (PbO), the second impure form being lead dioxide (PbO2), and the third impure form being lead hydroxide (Pb(OH)2). Also, in selected alternative implementations, the first, second, and / or third impure forms may be any other compound of lead other than oxide.

[0075] Additional implementations are also directed to equipment for recovering near pure lead from impure lead paste containing one or more of lead monoxide (PbO), lead dioxide (PbO2), or lead hydroxide (Pb(OH)2) (or in certain such alternative implementations, any other compound(s) of lead other than the oxide), which equipment comprises combining the impure lead paste with an electrolyte to produce a slurry, the electrolyte removing the lead monoxide (PbO), lead dioxide (PbO2), or lead hydroxide (Pb(OH)2) (or in certain such alternative implementations, any other compound(s) of lead other than the oxide) in the lead paste. a mixer for forming said slurry, which is a mixture of impure lead paste and electrolyte, so as not to dissolve other compounds (compounds) of lead (Pb) and lead (Pb(OH)), an electrolysis device for performing solid-state electrolysis on the slurry to form spongy lead and residual components, whereby a portion of the electrolyte can be discharged when the solid-state electrolysis is completed, a transformer including a press for mechanically separating the spongy lead from substantially all of the remaining electrolyte to produce lead bricks, and a smelter for smelting the lead bricks into molten lead and dross, whereby only near-pure lead remains after the dross is removed. In certain such implementations, the mixer may further comprise a desulfurization device for converting lead sulfate (PbSO4) in the lead paste to lead hydroxide (Pb(OH)2) before forming the slurry. In selected implementations, the mixer may further combine at least one auxiliary chemical with the slurry.

[0076] For all of the various implementations disclosed herein, alternative implementations are also contemplated in which the horizontal cathode is instead a horizontal anode and the suspended anode is instead a suspended cathode. Additionally, each step of the process performed by the various implementations disclosed herein is performed and controlled by a processing device or other computing environment, including, but not limited to, the timing of each step of operation, coordination between different electrolysis cells, slurry lines, conveyor belts, etc., and changes in time and charge utilized throughout the electrolysis process, as well as receiving and reacting to feedback from electrical resistance and other detectable events from the ongoing electrolysis.

[0077] <Electrolytes and Support Chemicals>

[0078] As disclosed earlier herein, sodium hydroxide (NaOH) as well as potassium hydroxide (KOH) and the like may also be used as electrolytes for the subsequent electrolytic treatment (e.g., electrolysis) of the lead paste, in which case the resulting lead slurry is a mixture of desulfurized lead paste and electrolyte (not its solution in the chemical sense). Note that this approach differs from the typical electrolytic treatment of lead paste dissolved and suspended in an electrolyte solution, in that the typical electrolytic treatment does not require auxiliary chemicals, whereas the electrolytic treatment of the mixture benefits from auxiliary chemicals.

[0079] FIG. 5A is an annotated chemical diagram of the molecular structure of lead monoxide (PbO) 502, lead dioxide (PbO2) 504, and lead hydroxide (Pb(OH)2) 506 (collectively "lead oxide components" or "lead oxides"). FIG. 5B is an annotated chemical diagram of the molecular structure of lead sulfate (PbSO4), shown for clarity with and without binding charge 508a and 508b (i.e., the lead (Pb) atom is juxtaposed with two oxygen atoms that are single-bonded to a sulfur atom). As previously mentioned, lead paste obtained from LAB during recycling typically contains a portion of pure lead as well as lead monoxide, lead dioxide, and lead sulfate.

[0080] Lead monoxide (PbO), also commonly referred to as lead(II) oxide, has an oxidation state of +2. PbO is formed during discharge of the LAB as a proton-electron mechanism of PbO2 reduction. (Note that the positive plate of the LAB is composed of PbO2, while the negative plate of the LAB is composed of pure lead, Pb.)

[0081] Lead dioxide (PbO2), also commonly called lead(IV) oxide, has an oxidation state of +4. The positive plates of the LAB are composed of PbO2; in contrast, the negative plates of the LAB are composed of pure lead (Pb).

[0082] Lead hydroxide (Pb(OH)2), commonly referred to as lead(IV) oxide or, imprecisely, as "lead hydrate" (this latter term is also used to refer to Pb(H2O)2), has an oxidation state of +2. Pb(OH)2 is produced by the interaction of the PbO2 plates in the LAB with the aqueous sulfuric acid (H2SO4) of the LAB (and PbSO4 is also produced). As previously described herein, lead sulfate (PbSO4) is converted to lead hydroxide (Pb(OH)2) during desulfurization, which occurs prior to electrolysis.

[0083] For the electrolysis process to successfully recover elemental lead (Pb) from the lead oxides present in the lead slurry prepared for solid-state electrolysis, one or more auxiliary chemicals can be added to the lead slurry mixture (including the electrolyte and lead oxide components) prior to electrolysis. During electrolysis, these auxiliary chemicals effectively enable the oxygen (O) and / or hydroxide (OH) molecules in the lead oxide to dissociate from the lead (Pb) and combine to form gaseous O2 (which can then dissipate from the mixture into the surrounding air) and / or water (H2O) (which can then remain in the mixture and be pushed out or boiled off in subsequent processing of the resulting elemental lead (Pb).

[0084] 6 is a block diagram of an exemplary computing environment that can be used in conjunction with the exemplary implementations and aspects as disclosed and described with respect to the other figures presented herein. The computing system environment is only one example of a suitable computing environment and is not intended to suggest any limitation as to the scope of use or functionality.

[0085] Numerous other general purpose or special purpose computing system environments or configurations can be used. Examples of well-known computing systems, environments, and / or configurations suitable for use include, but are not limited to, personal computers (PCs), server computers, handheld or laptop devices, multiprocessor systems, microprocessor-based systems, network PCs, minicomputers, mainframe computers, embedded systems, distributed computing environments that include any of the above systems or devices, etc.

[0086] Computer-executable instructions such as program modules executed by a computer may be used. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Distributed computing environments may also be used in which tasks are performed by remote processing devices that are linked through a communications network or other data transmission medium. In a distributed computing environment, program modules and other data may be located in both local and remote computer storage media including memory storage devices.

[0087] The various example logic, logic blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed using a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), an analog-to-digital converter (ADC), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, discrete data acquisition components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Furthermore, at least one processor may comprise one or more modules operable to perform one or more of the steps and / or actions described above.

[0088] With reference to Figure 6, an exemplary system for implementing aspects described herein includes a computing device, such as computing device 600. In a basic configuration, computing device 600 typically includes at least one processing unit 602 and memory 604. Depending on the exact configuration and type of computing device, memory 604 may be volatile (such as random access memory (RAM)), non-volatile (such as read only memory (ROM), flash memory, etc.), or a combination of the two. This basic configuration is illustrated in Figure 6 by dashed line 606 and may be collectively referred to as the "computing" components.

[0089] Computing device 600 may have additional features / functionality. For example, computing device 600 may include additional storage (removable and / or non-removable) including, but not limited to, magnetic or optical disks or tape. Such additional storage is illustrated in FIG. 6 as removable storage 608 and non-removable storage 610. Computing device 600 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by device 600 and can include both volatile and nonvolatile media, and both removable and non-removable media.

[0090] Computer storage media includes volatile and nonvolatile media, as well as removable and non-removable media, implemented in any method or technology for storage of information, such as computer-readable instructions, data structures, program modules or other data. Memory 604, removable storage 608, and non-removable storage 610 are all examples of computer storage media. Computer storage media include, but are not limited to, RAM, ROM, Electrically Erasable Program Read Only Memory (EEPROM), Flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVDs) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store information and that can be accessed by computing device 600. Any such computer storage media may be part of computing device 600.

[0091] The computing device 600 may include communication connections 612 that allow the device to communicate with other devices. The computing device 600 may also have input devices 614, such as a keyboard, mouse, pen, voice input device, touch input device, etc. Output devices 616, such as a display, speakers, printer, etc. may also be included. All of these devices are well known in the art and need not be described at length here. The computing device 600 may be one of multiple computing devices 600 interconnected by a network. As may be appreciated, the network may be any suitable network, with each computing device 600 connected to the network via the communication connections 612 in any suitable manner, and each computing device 600 may communicate with one or more of the other computing devices 600 in the network in any suitable manner. For example, the network may be a wired or wireless network, such as within an organization or home, and may include a direct or indirect connection to an external network, such as the Internet. Additionally, PCI, PCIe, and other bus protocols may be utilized to incorporate the various implementations described herein into other computing systems.

[0092] <Interpretation of the disclosure of this specification>

[0093] It should be understood that the various techniques described herein may be implemented in connection with hardware or software or, where appropriate, with a combination thereof. Thus, the processes and apparatus of the presently disclosed subject matter, or certain aspects or portions thereof, may take the form of program code (i.e., instructions) embodied in a tangible medium, such as a floppy disk, a CD-ROM, a hard drive, or any other machine-readable storage medium, which when loaded and executed by a machine, such as a computer, causes the machine to become an apparatus for practicing the presently disclosed subject matter.

[0094] When executing program code on a programmable computer, the computing device generally includes a processor, a processor-readable storage medium (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. One or more programs may implement or utilize the processes described in connection with the subject matter disclosed herein, for example, through the use of APIs, reusable controls, etc. Such programs may be implemented in a high-level procedural or object-oriented programming language to communicate with a computer system. However, the programs may be implemented in assembly or machine language. In either case, the language may be a compiled or interpreted language, which may be combined with a hardware implementation.

[0095] Although example implementations may refer to utilizing aspects of the presently disclosed subject matter in the context of one or more stand-alone computer systems, the subject matter is not limited thereto, but rather may be implemented in connection with any computing environment, for example, a networked or distributed computing environment. Furthermore, aspects of the presently disclosed subject matter may be implemented within or across multiple processing chips or devices, and storage may similarly be implemented across multiple devices. Such devices may include, for example, PCs, network servers, and handheld devices.

[0096] In certain implementations described herein, a cloud operating environment may be used that supports providing computing, processing, storage, data management, applications, and other functionality as abstract services, rather than as standalone products of computer hardware, software, and the like. Services may be provided by virtual servers that may be implemented as one or more processes on one or more computing devices. In some implementations, processes may be transferred between servers without disrupting the cloud service. In a cloud, shared resources (e.g., computing, storage) may be provided to computers, including servers, clients, and mobile devices, over a network. A variety of networks (e.g., Ethernet, Wi-Fi, 802.x, cellular) may be used to access cloud services. A user interacting with a cloud may not need to know the details (e.g., location, name, server, database, etc.) of the devices that are actually providing the services (e.g., computing, storage). A user may access cloud services, for example, via a web browser, a thin client, a mobile application, etc., or in other ways. To the extent that physical components of hardware and software are described herein, equivalent functionality provided via a cloud operating environment is also contemplated and disclosed.

[0097] Further, the controller service may reside in the cloud and rely on servers or services to perform processing and on data stores or databases to store data. Although one server, one service, one data store, and one database may be used, multiple server, service, data store, and database instances may reside in the cloud and thus be used by the controller service. Similarly, a variety of devices may access the controller service in the cloud, including, but not limited to, computers, tablets, laptop computers, desktop monitors, televisions, personal digital assistants, and mobile devices (e.g., mobile phones, satellite phones, etc.). Different users using different devices in different locations may access the controller service through different networks or interfaces. In one example, the controller service may be accessed from a mobile device. In another example, parts of the controller service may reside on the mobile device. In either case, the controller service may perform actions such as, for example, displaying content on a secondary display, displaying an application (e.g., a browser) on a secondary display, displaying a cursor on a secondary display, displaying controls on a secondary display, and / or generating control events in response to interactions on the mobile device or other services. In certain implementations, a controller service may perform some of the methods described herein.

[0098] <Possible alternative forms>

[0099] Although the subject matter has been described in language specific to structural features and / or methodological acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. Moreover, it will be apparent to one skilled in the art that other implementations may be practiced that depart from the specific details disclosed above.

[0100] The above drawings and the following specific structural and functional descriptions are not presented to limit the scope of the invention or the scope of the appended claims. Rather, the drawings and descriptions are presented to teach one of ordinary skill in the art to make and use the invention for which patent protection is claimed. Those skilled in the art will appreciate that for clarity and understanding, not all features of a commercial implementation of the invention are described or illustrated. Those skilled in the art will further appreciate that the block diagrams herein provide conceptual views of exemplary circuitry embodying the principles of the technology, and that the flow charts, state transition diagrams, pseudocode, and the like represent various processes embodied in a computer-readable medium and executed by a computer or processor, whether or not such a computer or processor is explicitly shown. The functionality of the various elements comprising the functional blocks can be provided using dedicated electronic hardware and electronic circuitry capable of executing computer program instructions in conjunction with appropriate software. Those skilled in the art will also appreciate that the development of an actual commercial implementation incorporating aspects of the invention will require numerous implementation-specific decisions to achieve the ultimate goal of the commercial implementation developer. Such implementation-specific decisions may include, but are not limited to, compliance with system-related, business-related, government-related, and other constraints, which may vary depending on the particular implementation, location, and time. While the developer efforts may be complex and time-consuming in absolute terms, these efforts are routine for those of ordinary skill in the art having the benefit of this disclosure.

[0101] It should also be understood that the implementations disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Thus, the use of singular forms such as, but not limited to, "a" is not intended to limit the number of items. Also, the use of related terms such as, but not limited to, "top," "bottom," "left," "right," "upper," "lower," "lower," "upper," "side," and the like, are used in the written description for clarity with specific reference to the drawings, and are not intended to limit the scope of the invention or the appended claims. For specific implementations described with reference to block diagrams and / or operational illustrations of methods, it should be understood that each block of the block diagrams and / or operational illustrations, and combinations of blocks in the block diagrams and / or operational illustrations, may be implemented by analog and / or digital hardware, and / or computer program instructions. The computer program instructions used in the implementations disclosed herein may be written in an object-oriented programming language, a conventional procedural programming language, or low-level code such as assembly language and / or microcode. The programs may be executed entirely on a single processor and / or across multiple processors, as a stand-alone software package or as part of another software package. Such computer program instructions may be provided to a processor of a general purpose computer, a special purpose computer, an ASIC, and / or other programmable data processing system. The executed instructions may also create structures and functions for implementing the actions specified in the block diagrams and / or operational diagrams described above. In some alternative implementations, the functions / actions / structures depicted in the figures may occur out of the order shown in the block diagrams and / or operational diagrams. For example, two operations shown to occur in succession may in fact be performed substantially simultaneously or the operations may be performed in the reverse order, depending on the functions / acts / structures involved.

[0102] The term "computer-readable instructions" as used above refers to any instructions that may be executed by a processor and / or other components. Similarly, the term "computer-readable medium" refers to any storage medium that may be used to store computer-readable instructions. Such media may take many forms, including but not limited to non-volatile media, volatile media, and transmission media. Non-volatile media may include, for example, optical or magnetic disks, such as storage devices. Volatile media may include dynamic memory, such as main memory. Transmission media may include coaxial cables, copper wire, and optical fibers, including the wires of a bus. Transmission media may also take the form of sound or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media include, for example, floppy disks, flexible disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, DVDs, any other optical media, punch cards, paper tape, any other physical media with a pattern of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cartridge, carrier wave, or any other medium from which a computer can read.

[0103] In the foregoing description, for purposes of explanation and not limitation, specific details of particular nodes, functional entities, techniques, protocols, standards, etc. are provided to provide an understanding of the described technology. In other instances, detailed descriptions of well-known methods, apparatus, techniques, etc. are omitted so as not to obscure the description with unnecessary detail. All descriptions reciting principles, aspects, embodiments, and implementations, as well as specific examples, are intended to encompass both structural and functional equivalents, and such equivalents are intended to include both currently known equivalents and equivalents developed in the future, regardless of structure, i.e., any elements developed to perform the same function. While the disclosed implementations have been described with reference to one or more specific implementations, those skilled in the art will recognize that many variations are possible. Accordingly, each of the foregoing implementations and obvious variations thereof are deemed to be within the spirit and scope of the disclosed implementations, as set forth in the following claims.

[0104] <Copyright Notice>

[0105] A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of this patent document or the patent disclosure in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

Claims

1. A method (60') for recovering near-pure metal from an impure metal material (130) containing a target metal, comprising: combining (68) the impure metallic material (130) with an electrolyte (140) to form a slurry (150), the slurry (150) being a mixture of the impure metallic material (130) and the electrolyte (140) such that the electrolyte (140) does not dissolve the target metal in the impure metallic material (130); performing solid-state electrolysis (72) on the slurry (150) to form a target metal deposit (132) and a residual component (142); mechanically separating (74) the target metal from substantially all of the electrolyte (140) and at least a portion of the remaining components (142); melting (80) the target metal deposit (132) and removing dross so that the remaining melted target metal is near pure without smelting; The method (60') includes:

2. The method (60') of claim 1, further comprising adding (68) at least one auxiliary chemical to the slurry (150) prior to performing the solid-state electrolysis (72).

3. The method (60') of claim 2, further comprising mechanically separating (92) the dross into component materials for further processing.

4. 4. The method of claim 3, wherein the impure metallic material comprises a first impure form of the target metal and a second impure form of the target metal, the first impure form being chemically distinct from the second impure form.

5. 5. The method of claim 4, wherein the impure metallic material comprises a third impure form of the target metal, the third impure form being chemically distinct from the first impure form and the second impure form.

6. 6. The method (60') of claim 5, wherein the target metal formed during solid-state electrolysis (72) is derived from the first impure form, the second impure form, and the third impure form.

7. 7. The method (60') of claim 6, wherein the at least one auxiliary chemical comprises a first auxiliary chemical, a second auxiliary chemical, and a third auxiliary chemical, the first auxiliary chemical enabling the first impure form of solid-state electrolysis (72), the second auxiliary chemical enabling the second impure form of solid-state electrolysis (72), and the third auxiliary chemical enabling the third impure form of solid-state electrolysis (72).

8. 8. The method (60') of claim 7, wherein the target metal is elemental lead (Pb), the first impure form is lead monoxide (PbO), the second impure form is lead dioxide (PbO2), and the third impure form is lead hydroxide (Pb(OH)2).

9. 10. The method (60') of claim 8, further comprising desulfurizing (66) the impure metallic material (130) prior to combining (68) the impure metallic material with the electrolyte (140) to form the slurry (150).

10. 10. The method (60') of claim 9, wherein the solid-state electrolysis (72) is carried out using an electrolysis apparatus including a horizontal cathode (120) on which the slurry (150) is placed for the solid-state electrolysis (72).

11. 1. A system (100) for recovering near-pure metals from an impure metal material (130) containing a target metal, the system (100) comprising: combining (68) the impure metallic material (130) with an electrolyte (140) to form a slurry (150), the slurry (150) being a mixture of the impure metallic material (130) and the electrolyte (140) such that the electrolyte (140) does not dissolve the target metal in the impure metallic material (130); performing solid-state electrolysis (72) on the slurry (150) to form a target metal deposit (132) and a residual component (142); mechanically separating (74) the target metal from substantially all of the electrolyte (140) and from at least a portion of the remaining components (142); Melting (80) the target metal deposit (132) and removing dross so that the remaining molten target metal is near pure without smelting. The system (100) includes at least one subsystem for:

12. 12. The system (100) of claim 11, further comprising at least one subsystem for adding (68) at least one auxiliary chemical to the slurry (150) prior to performing the solid-state electrolysis (72).

13. The system (100) of claim 11, further comprising at least one subsystem for mechanically separating (92) the dross into component materials for further processing.

14. 12. The system of claim 11, wherein the impure metallic material (130) comprises a first impure form of the target metal, a second impure form of the target metal, and a third impure form of the target metal, the first impure form being chemically distinct from the second impure form, and the third impure form being chemically distinct from the first impure form and the second impure form.

15. 1. An apparatus (10) for recovering near-pure lead from an impure lead paste (130) containing one or more of lead monoxide (PbO), lead dioxide (PbO2), or lead hydroxide (Pb(OH)2), comprising: a mixer (26) for combining the impure lead paste (130) with an electrolyte (140) to form a slurry (150), the slurry (150) being a mixture of the impure lead paste (130) and the electrolyte (140) such that the electrolyte (140) does not dissolve lead monoxide (PbO), lead dioxide (PbO2), or lead hydroxide (Pb(OH)2) in the lead paste (130); an electrolysis device (28) for performing solid-state electrolysis (72) on the slurry (150) to form sponge lead (132) and residual components (142), the electrolysis device (28) being capable of discharging a portion of the electrolyte (142) when the solid-state electrolysis (72) is completed; a transformer (30) including a press for mechanically separating (92) said sponge lead (132) from substantially all of the remaining electrolyte (140) to produce a lead brick; a smelter (32) for smelting (80) said lead bricks into molten lead and dross, where only near-pure lead (48) remains after said dross is removed; An apparatus (10).

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