Electrochemical Device and System for Metal Recovery

This application claims priority to U.S. Provisional Patent Application No. 63/633,309, filed on Apr. 12, 2024, which is incorporated by reference herein in its entirety.

The present disclosure relates to metal recovery from a liquid stream using an electrochemical device.

Electrowinning is an electrochemical process used to recover metals from concentrated solutions, typically for example, in a range of 30 to 50 grams/Liter (g/L) or 30,000 to 50,000 parts-per-million (ppm). In this process, a voltage is applied across two electrodes, the positively charged anode and the negatively charged cathode, which are submerged in the concentrated metal containing solution. The anode can be, for example, a mixed-metal oxide (MMO), and the cathode can be, for example, 316 stainless steel or titanium (Ti). As a result, the positively charged metal ions will electrodeposit or electroplate out of the solution onto the cathode as a solid. This process can be used to recover metals, including but not limited to, copper, zinc, nickel, cobalt, gold, and/or silver, from wastewater streams.

According to some embodiments, a metal recovery electrochemical cell includes comprising: a metal-based anode; a metal-based cathode; and a metal-based housing with a conical shape and a draft angle of about 0.01 to about 1 degree, the draft angle of the metal-based housing being an angle between a vertical centerline of the metal-based housing and an adjacent vertical side of the metal-based housing, when both are extrapolated to form an angle.

In some embodiments, the draft angle of the metal-based housing is about 0.15 to about 0.60 degrees.

In other embodiments, the metal-based cathode further comprises a draft angle that is an angle between the vertical centerline of the metal-based cathode and an adjacent vertical side of the metal-based cathode, when both are extrapolated to form an angle.

In one or more embodiments, the metal-based cathode draft angle is about 0.01 to about 1 degree.

In some embodiments, the draft angle of the metal-based cathode is about 0.15 to about 0.60 degrees.

In other embodiments, the metal recovery electrochemical cell further comprises a cylindrical edge guard on a top of the metal-based cathode.

Yet in other embodiments, the metal recovery electrochemical cell further comprises a cylindrical edge guard on a bottom of the metal-based cathode.

In one or more embodiments, the metal-based anode is a titanium-coated mixed-metal oxide.

In some embodiments, the metal-based cathode is a 316 stainless steel sheet.

In other embodiments, the metal-based housing comprises a 316 stainless steel.

Yet, in other embodiments, the metal recovery electrochemical cell of further comprises a separator between the metal-based anode and the metal-based cathode.

In one or more embodiments, the metal recovery electrochemical cell of further comprises a membrane arranged on the metal-based anode and the metal-based cathode.

In some embodiments, inner diameter of a first end of the metal-based housing is different than an inner diameter of a second end of the metal-based housing.

In other embodiments, the metal-based cathode comprises a metal with a linear polarization resistance (LPR) of less than 0.1 millimeters per year (mmpy), as measured by ISO 17475-Corrosion of Metals and Alloys.

In some embodiments, a metal recovery electrochemical system comprises a metal purification electrochemical cell comprising at least one carbon-based electrode and at least one metal-based electrode; and a metal recovery electrochemical cell comprising a metal-based cathode and a metal-based anode, and a metal-based housing with a conical shape and a draft angle of about 0.01 to about 1 degree, the draft angle of the metal-based housing being an angle between a vertical centerline of the metal-based housing and an adjacent vertical side of the metal-based housing, when both are extrapolated to form an angle; wherein the metal recovery electrochemical cell is arranged downstream from the metal purification electrochemical cell.

In some embodiments, the at least one carbon-based electrode is a carbon felt, a woven carbon cloth, a carbon film, a non-woven, or an activated carbon material.

In other embodiments, the at least one metal-based electrode comprises a metal with one or more metal oxides arranged on the metal.

Yet in other embodiments, the system further comprises a regeneration tank arranged between the metal purification electrochemical cell and the metal recovery electrochemical cell.

In some embodiments, a metal recovery electrochemical cell includes a metal-based anode; a metal-based cathode surrounding the metal-based anode; and a cap covering an end of the metal-based cathode, the cap comprising a cylindrical edge guard with an internal cylindrical wall, a medial cylindrical wall, and a circumferential wall.

In other embodiments, the metal recovery electrochemical cell further comprises a metal-based housing with a cylindrical shape.

Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with the advantages and the features, refer to the description and to the drawings.

Electrowinning for metal recovery was established in the. The standard method has largely remained unchanged; however, the applications have greatly increased. This electrochemical technology can be used to recover metals from wastewater and/or contaminants from process water in a variety of industries, including but not limited to, metal finishing, printed circuit board (PCB) manufacturing, semiconductor manufacturing, mining, lithium-ion battery recycling, medical device manufacturing, and electronics recycling (i.e., E-waste).

Conventional electrowinning cells encounter several challenges, including but not limited to, low current efficiency, high energy consumption, non-uniform metal deposition, and difficulties harvesting the deposited metal. Cell designs and electrode configurations vary from a design as simple as two rectangular electrodes facing one another and submerged in an open tank to more sophisticated cylindrical cells. In the latter case, a solid cylindrical anode is surrounded by a cylindrical cathode and enclosed in a housing. The cell is filled with a metal-containing feed stream. When a voltage is applied across the electrodes, metal is deposited from the liquid stream onto the interior surface of the cathode to form a solid metal cylinder or tube of the deposited metal. As the metal in the liquid stream is depleted, the deposition rate decreases. When most of the metal is recovered, the tube is harvested by extracting it from the housing. The deposited metal risks bending, breaking, or warping upon extraction, or worse, remaining stuck inside the housing and unable to be extracted.

Accordingly, described herein are devices, systems, and methods that address the foregoing challenges. In some embodiments, devices, systems, and methods include a conical metal recovery electrochemical cell comprising a metal-based housing/current collector with a draft angle of less than 1 degree, a metal-based cathode/shim, a metal-based anode, and at least one edge guard surrounding at least one end of the cathode/shim to provide advantages of uniform metal deposition on the entire interior surface of the cathode/shim and ease of extraction of the final metal tube, overcoming the foregoing challenges.

illustrate the metal recovery electrochemical cellaccording to some embodiments. The metal recovery electrochemical cellincludes a feed stream inletand a feed stream outlet, shown in.illustrates an optional handle, a top cap(or first cap), a bottom cap(or second cap), a housing(also functioning as a current collector), a cathode shim(also functioning as a shim), an anode, and optional edge guards,on the top and/or bottom (or first end and/or second end), respectively, of the cathode(shim). The metal recovery electrochemical cellfurther includes electrical contacts (or electrical connections) and associated wiring to provide the necessary electrical connections to the electrical power supply (not shown).

In some embodiments, the metal recovery electrochemical cellincludes a metal-based housing. Metal-based housingis an outer shell or enclosure of the electrochemical cell, protecting internal components. The metal-based housingcan vary in shape and material.

In one or more embodiments, the housingis cylindrical shaped, conical shaped, contoured, or any combination thereof.

Housingalso serves the function of a current collector. As the current collector, the housingis a conductive component that transfers electrons between the active material and the external circuit and improves charge/discharge efficiency.

Non-limiting examples for the housinginclude 304 stainless steel, 316 stainless steel, titanium, copper, aluminum, or a combination thereof. 316 stainless steel includes iron plus 16-18% chromium, 10-14% nickel, and 2-3% molybdenum. 304 stainless steel includes iron plus 18-20% chromium, and 8-10.5% nickel. In other embodiments, the housingis a metal sheet. In some embodiments, housingis a 316 stainless steel sheet.

In some embodiments, the housinghas a thickness of at least 0.105 inches. In other embodiments, the housinghas a thickness of about 0.059 to about 0.140 inches. Yet, in other embodiments, the housinghas a thickness of about or in any range between about 0.059, 0.069, 0.079, 0.089, 0.099, 0.109, 0.119, 0.129, 0.139, 0.140, 0.149, 0.159, 0.169, 0.179, 0.189, 0.199, 0.209, 0.219, 0.229, 0.239, 0.249, 0.259, 0.269, 0.279, 0.289, 0.299, 0.309, 0.319, 0.329, 0.339, 0.349, 0.359, 0.369, 0.379, 0.389, 0.399, 0.409, 0.419, 0.429, 0.439, 0.449, 0.459, 0.469, 0.479, 0.489, 0.499, and 0.500 inches.

In some embodiments, as shown in, the electrochemical deviceincludes a housingwith a draft angle. In embodiments, the draft angleis less than 1 degree. In other embodiments, the metal recovery electrochemical cellincludes a housingthat has a conical shape, with an inner diameter of a first end being different than an inner diameter of a second end.

As used herein, reference to the “draft angle” with respect to the housing or cathode means the angle between a vertical centerlineof the housing or cathode and an adjacent vertical side of the housing or cathode, when both are extrapolated to form an angle. When used in reference to the housing, the draft angle is an angle between the vertical centerline of the metal-based housing and an adjacent vertical side of the metal-based housing, when both are extrapolated to form an angle. When used in reference to the cathode, the draft angle is an angle between the vertical centerline of the cathode and an adjacent vertical side of the cathode, when both are extrapolated to form an angle.

A draft angle is a taper applied to the vertical walls of a mold, which allows for easier release/removal/extraction of the plated metal part from the shim and housing, and for the finished metal tube (housing or cathode) in the instant application. In conventional injection molding and die casting methods, molten material, often metal, is disposed into a mold, also often metal, to fabricate parts. For these applications, a small draft angle of about 1.5 to 2 degrees is generally used for metal-on-metal molding functions, and typically, 3 degrees is used to ensure the mold can separate properly.

In contrast to these conventional processes, for electrowinning used in the instant application, the draft angle need only be large enough to not require a crane for part removal and is therefore less than 1 degree. A minimal amount of force can then be used to extract the finished metal tube.

Electroforming is another process that can be used to fabricate metal parts. Electroforming is a metal forming process that uses electrodeposition to form or grow metal parts onto a model, known as a mandrel. The purpose of electroforming is to fabricate a specific part, not to recover a metal. In contrast to electrowinning, electroformers would not use a draft angle because it would mar the surface of the part, unlike the instant application, where the draft angle is critical for extraction of the finished metal tube.

In some embodiments, the draft angleof the housingis about 0.01 to about 1 degree. In other embodiments, the draft angleof the housingis about 0.2 to about 0.8 degree. In embodiments, the housinghas a draft angle of about 0.15 to about 0.60 degrees. Still yet, in other embodiments, the draft angleof the housingis about or in any range between about 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, and 1.00 degree.

In one or more embodiments, the metal-based housinghas a conical shape and a draft angle of about 0.01 to about 1 degree, with the draft angle of the metal-based housing being an angle between the vertical centerline of the metal-based housing and an adjacent vertical side of the metal-based housing, when both are extrapolated to form an angle.

In some embodiments, the metal-based housinghas a cylindrical shape and a draft angle of about 0 degree, with the draft angle of the metal-based housing being an angle between the vertical centerline of the metal-based housing and an adjacent vertical side of the metal-based housing, when both are extrapolated to form an angle.

illustrates housingwith a draft angleless than 1 degree according to some embodiments. The metal recovery electrochemical cellincludes a conical housingthat is 2 feet in heightwith inner diameters at the top 403 and bottombeing different, and in certain embodiments, being 6.35 inches and 5.95 inches, respectively, yielding a cone half angle (CHA) of 0.48 degrees. The CHA corresponds to the draft angle. In one or more embodiments, the draft angleof the housingis at least 0.48 degrees.

In one or more embodiments, the housinghas a heightof about 3 feet with inner diameters at the top 403 (first end) and bottom(second end) being different, and in certain embodiments, being 6.35 inches and 5.95 inches, respectively, yielding a cone half angle (CHA) of 0.32 degrees. The CHA corresponds to the draft angle. In one or more embodiments, the draft angleof the housingis 0.32 degrees.

In some embodiments, the housinghas a heightof about 1 to about 4 feet. In some embodiments, the housinghas a heightabout or in any range between about 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, and 4.0 feet.

In other embodiments, the housinghas an inner diameter at the top 403 (first end) of about 4 to about 8 inches. In other embodiments, the housinghas an inner diameter at the top 403 (first end) of about or in any range between about 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, and 8.0 inches.

In some embodiments, the housinghas an inner diameter at the bottom(second end) of about 3.8 to about 7.8 inches. Yet, in other embodiments, the housinghas an inner diameter at the bottom(second end) about or in any range between about 3.8 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, and 7.8 inches.

In some embodiments, the cathodewithin the housingalso serves as a shim, and is also referred to herein as a mandrel/starter sheet. In one or more embodiments, the housingis cylindrical shaped, conical shaped, contoured, or any combination thereof.

The cathodeis placed on the inner wall of housingand makes direct contact with the inner wall of the housing, such that there is no space between the inner wall of the housingand the cathode. The cathodeis in a form of a metal sheet, a foil sheet, a mesh sheet, a metal rod, and/or a metal tube.

Non-limiting examples of materials for the metal cathodeinclude one or more conductive metals, for example, aluminum, copper, graphite, titanium, 316 stainless steel, 304 stainless steel, or a combination thereof. The metal cathodeis a solid (i.e., non-porous) 316 stainless steel sheet in some embodiments.

In one or more embodiments, the metal cathodeincludes a metal with a conductivity range of about 1.0×10to about 6.5×10S/m, as measured by ASTM E1004 test method at room temperature. In other embodiments, the metal cathodeincludes a metal with a conductivity range of about or in any range between about 1.0×10, 2.5×10, 4.0×10, 5.5×10, 7.0×10, 9.0×10, 1.2×10, 1.6×10, 2.1×10, 2.7×10, 3.4×10, 4.2×10, 5.1×10, 5.8×10, and about 6.5×10S/m, as measured by ASTM E1004 test method at room temperature.