Electrowinning cell, system, and method for producing soft deposits on electrowinning cathodes and for automatically cleaning and removing hard and soft deposits

Abstract

An electrowinning system (1) may comprise a filter (11) for filtering barren solution (38), an electrowinning cell (100) configured for "self-cleaning", an electrode support hanger (123) configured for slidably receiving electrodes (121, 122), a discharge cleaning nozzle (138) for moving product / sludge (43) to a lower discharge (130), a wash system (108) which may distribute filtered barren solution (38) for cleaning one or more electrodes (121, 122), and / or a lifting system (107) for mechanically raising and / or lowering electrodes (121, 122) in relation to a tank (111) Other novel improvements include a sloped floor (19) for a barren solution return tank (5), a unique (e.g., 3-way) valve (16) arrangement for recycling barren solution (38) to one or more portions of the electrowinning system (1) and inlets (117) which allow side removal and installation of novel spray bars (147) from the tank (111).

Description

[0001] ELECTROWINNING CELL, SYSTEM, AND METHOD FOR PRODUCING SOFT DEPOSITS ON ELECTROWINNING CATHODES AND FOR AUTOMATICALLY CLEANING AND REMOVING HARD AND SOFT DEPOSITS

[0002] FIELD OF THE INVENTION

[0003] Embodiments of the present invention pertain to improvements to electrowinning apparatus and methods of electrowinning which are particularly useful for precious metals recovery, such as for gold and silver recovery processes.

[0004] BACKGROUND TO THE INVENTION

[0005] Reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge in the arts. Reference is made to Applicant’s co-pending U.S. Provisional Patent application Ser. No. 63 / 320,359 filed March 16, 2022, and PCT / IB2023 / 052604 file March 16, 2023 titled “SYSTEM AND METHOD FOR CONTROLLING OR REMOVING HARD DEPOSITS ON ELECTROWINNING CATHODES”, which are both incorporated by reference for any and all purposes as if fully set forth herein.

[0006] During electrowinning processes within the PGM, gold, and silver mining industry, precious metals may form hard deposits on electrowinning cathodes. These “hard deposits” may be very difficult to remove from the electrowinning cathodes after plating. Using wire mesh cathodes in an electrowinning cell further complicates removal. Since these hard deposits contain valuable precious metals, it is desirable to remove as much of these difficult-to-remove hard deposits from the electrowinning cathodes to maximize downstream recovery.

[0007] Industry practice has, heretofore, included attempts to recover hard-deposited precious metals from electrowinning cathodes by employing a “reverse-polarity step”, wherein hard deposit removal from a cathode is facilitated by temporarily configuring the electrowinning cell to polarize the hard-deposited cathode as the anode would typically be, and simultaneously charging the anode as the cathode would typically be during electrowinning, thus effectively “re-plating” hard-deposited precious metals from the cathode onto the anode. This is followed by subsequent re-plating from the anode back to the cathode in a normal electrowinning cell operating configuration.

[0008] Alternatively, conventional practice has involved attempts to remove the hard- deposited cathodes by smelting them in their entirety. In this energy-intensive and carbon impactful process, the hard deposit-laden cathode mesh is ultimately destroyed in a furnace (along with its in-situ deposits), and the hard deposits containing valuable precious metals are recovered in their molten state. Aside from being a heat and energy-intensive process, the drawback of melting wire cathodes in a furnace is that the cathodes are used and treated as sacrificial consumables, rather than renewable / re-useable components of the electrowinning process. To ensure purity, the molten metal values must be finely separated from the molten metal wire and this introduces another critical pyro-refinement step to the recovery process. Moreover, to date, conventional practice has been to clean anodes and / or cathodes by manually raising them or lifting them out of an electrowinning cell with a crane or hoist, and manually spraying them with high pressure water through a hose. This not only exposes maintenance personnel to fumes and possible chemical exposure, but requires additional staff, operation shutdown (e.g., lock out / tag out), a supply of fresh water (which may not be recycled, and the complete draining of electrolyte from the electrowinning cell tank.

[0009] To this end, there are no known teachings within the prior art that would promote and / or ensure a “soft” cathode deposit during the electrowinning process. Moreover, heretofore, there are no known teachings within the prior art that relate to “softening” and / or “removal” of hard anode / cathode deposits. Moreover, to date, there are no technological offerings which would enable an electrowinning cell to “self-clean”. Moreover, there has been no electrowinning apparatus or system offerings that enable electrode cleaning without manual intervention (e.g., such as hoisting electrodes from the tank and manually pressure washing electrodes). Additionally, heretofore, have been no technological advancements which might allow electrode cleaning without necessarily draining an electrowinning cell of electrolyte.

[0010] OBJECTS OF THE INVENTION

[0011] It is an aim that embodiments of the invention provide an electrowinning apparatus and method which overcomes or ameliorates one or more of the disadvantages or problems described above - or, which at least provides a useful alternative to conventional electrowinning apparatus and methods.

[0012] It is an aim of some embodiments to eliminate or at least significantly reduce the formation of “hard” deposits containing precious metals (e.g., those containing silver and / or gold) on wire mesh cathodes.

[0013] It is an aim of some embodiments to provide an improved procedure, system, and / or electrowinning apparatus which is configured to discourage the formation of hard deposits and / or automatically remove soft deposits containing precious metals (e.g., those containing silver and / or gold) from wire mesh cathodes, without any significant manual human involvement or intervention (e.g., lock-out / tag-out, periodically manually draining the electrowinning cell of electrolyte, manually opening an electrowinning cell, manually hoisting electrodes from an electrowinning cell, manually pressure washing electrodes, removing rinse water from an electrowinning cell, manually returning the electrodes into the electrowinning cell tank, and / or refilling the electrowinning cell with electrolyte).

[0014] It is an aim of some embodiments to provide an improved procedure, system, and / or electrowinning apparatus which is configured to minimize or eliminate human operator exposure during a cathode / anode cleaning process (i.e. , provide electrowinning equipment which is configured to “self-clean” with minimal disruptions to the electrowinning process.

[0015] It is an aim of some embodiments to use electrode washing fluid cleaning mediums other than freshwater in order to reduce the need for a freshwater supply, conserve freshwater, reduce environmental impact, and eliminate time-consuming steps involved with draining an electrowinning cell of electrolyte in order to clean electrodes, and then re-fill the cell with electrolyte. It is an additional aim of some embodiments to improve metal balance at mine sites by eliminating or at least significantly reducing the amount of silver and / or gold inventory locked up within electrowinning cathodes in the refinery.

[0016] Other preferred objects of the present invention will become apparent from the following description.

[0017] SUMMARY OF INVENTION

[0018] According to embodiments of the invention, a novel electrowinning apparatus and method is disclosed.

[0019] A method of electrowinning a precious metal may comprise the step of providing an electrowinning solution containing dissolved metal ions of the precious metal therein, to an electrowinning cell having at least one cathode and at least one anode. The method may further comprise the step of depositing the precious metal onto the cathode by virtue of passing electrical current from the anode to the cathode.

[0020] The method may further comprise the step of softening the deposited precious metal deposited on the cathode or at least discouraging the formation of hard deposits of the precious metal onto the cathode. This may be accomplished, for instance, by virtue of at least temporarily, increasing a current density of the electrowinning cell and / or maintaining current density of the electrowinning cell to within a range of 40 to 200 A / m2of the total cathode area; at least temporarily, increasing a concentration of sodium cyanide within the electrowinning solution and / or maintaining a concentration of sodium cyanide within the electrowinning solution to within a range of 1 -4%; at least temporarily, adding silver cyanide to the electrowinning solution; performing a reverse polarity sequence by at least temporarily changing the charge of the cathode in the electrowinning cell; and / or at least temporarily, energizing an ultrasonic transducer provided to the electrowinning cell. The above steps for softening the deposited precious metal deposited on the cathode or at least discouraging the formation of hard deposits of the precious metal onto the cathode may be performed in any combination, as necessary to achieve optimal effect, without limitation.

[0021] According to other embodiments, the method may comprise the steps of altering a composition of the electrowinning solution in a separate mixing or storage tank. The method may include the step of delivering at least some of the electrowinning solution from the mixing or storage tank to the electrowinning cell. The method may include the step of softening the deposited precious metal deposited on the cathode or at least discouraging the formation of hard deposits of the precious metal onto the cathode. This may be achieved, for example by virtue of: at least temporarily, increasing a current density of the electrowinning cell and / or maintaining current density of the electrowinning cell to within a range of 40 to 200 A / m2of the total cathode area; at least temporarily, increasing a concentration of sodium cyanide within the mixing or storage tank and / or maintaining a concentration of sodium cyanide within the mixing or storage tank to within a range of 1 -4%; maintaining a concentration of sodium cyanide within the mixing or storage tank which is higher than a concentration of sodium cyanide used in the electrowinning cell; introducing an additive or reagent to the electrowinning solution in the mixing or storage tank; the additive comprising a hard electrowinning deposit remover selected from one or more of the group consisting of: one or more soft metals, one or more wetting acents, one or more surface modifiers, one or more viscosity modifiers, one or more releasing agents, one or more oxidants, one or more organic compounds; performing a reverse polarity sequence by at least temporarily changing the charge of the cathode in electrowinning cell; and / or at least temporarily, energizing an ultrasonic transducer provided to the electrowinning cell. The above steps for softening the deposited precious metal deposited on the cathode or at least discouraging the formation of hard deposits of the precious metal onto the cathode may be performed in any combination, as necessary to achieve optimal effect, without limitation.

[0022] Embodiments of the method disclosed herein may comprise the steps of depositing the precious metal on a cathode in an electrowinning cell 100; subsequently removing the cathode from the electrowinning cell, washing it using a wash system 108; and removing the deposited precious metal from the cathode using the wash system 108. Cathode deposit removal may be facilitated by virtue of performing at least one of the following steps: maintaining a current density of the electrowinning cell 100 which is within a range of 40 to 200 A / m2of the total cathode area; maintaining a concentration of sodium cyanide within a range of 1 -4%; introducing an additive or reagent to the electrowinning cell, pregnant leach solution (PLS) feed, barren solution return tank, and / or washing fluid cleaning medium used by the wash system 108 (e.g., supplied to the manifold(s) 115, branch / splitter 120, feed lines 116, inlets 117, and / or spray bars 147); the additive comprising a hard electrowinning deposit remover selected from one or more of the group consisting of: one or more soft metals, one or more wetting agents, one or more surface modifiers, one or more viscosity modifiers, one or more releasing agents, one or more oxidants, one or more organic compounds; performing a reverse polarity sequence by at least temporarily changing the charge of the cathode in the electrowinning cell; and / or at least temporarily, energizing an ultrasonic transducer provided to electrowinning cell. The above steps for removing the deposited precious metal from the cathode may be performed in any combination, in any desirable order (or steps performed simultaneously) as necessary to achieve optimal effect, without limitation.

[0023] Embodiments of an electrowinning circuit for recovering a precious metal from an electrowinning solution containing dissolved metal ions of the precious metal therein, is also disclosed. The electrowinning circuit may comprise an electrowinning cell having at least one cathode and at least one anode; and an electrical current passing from the anode to the cathode. The electrowinning circuit may further comprise means for softening the precious metal deposited on the cathode or at least discouraging the formation of hard deposits of the precious metal onto the cathode during electrowinning. Such means may comprise a rectifier configured to at least temporarily increase current density and / or configured for maintaining current density of the electrowinning cell within a range of 40 to 200 A / m2of the total cathode area; a pump and / or adjustable control valve configured for at least temporarily increasing a concentration of sodium cyanide within the electrowinning solution and / or configured for maintaining a concentration of sodium cyanide within the electrowinning solution to within a range of 1 -4%; a pump and / or adjustable control valve configured for at least temporarily adding silver cyanide to the electrowinning solution; a rectifier configured to reverse polarity of the anode and cathode for performing a reverse polarity sequence and at least temporarily changing the charge of the cathode in the electrowinning cell; and / or an energizable ultrasonic transducer provided to the electrowinning cell configured for mechanically removing the precious metal from the cathode using sound waves. The above features may be optionally provided to the electrowinning circuit in any combination, without limitation.

[0024] According to some embodiments, the electrowinning circuit may comprise a mixing or storage tank configured for receiving the electrowinning solution from the electrowinning cell and being further configured to aid in the softening the precious metal upon its deposition onto the cathode or at least discourage the formation of hard deposits of the precious metal onto the cathode. The electrowinning circuit may comprise a rectifier configured to at least temporarily increase current density and / or configured for maintaining current density of the electrowinning cell to within a range of 40 to 200 A / m2of the total cathode area. The electrowinning circuit may comprise a pump and / or adjustable control valve configured for: at least temporarily increasing a concentration of sodium cyanide within the mixing or storage tank, maintaining a concentration of sodium cyanide within the mixing or storage tank to within a range of 1 -4%, and / or maintaining a concentration of sodium cyanide within the mixing or storage tank to be higher than a concentration of sodium cyanide used in the electrowinning cell. The electrowinning circuit may comprise a pump and / or adjustable control valve configured for introducing an additive or reagent to solution to the mixing or storage tank; the additive or reagent comprising a hard electrowinning deposit remover selected from one or more of the group consisting of: one or more soft metals, one or more wetting agents, one or more surface modifiers, one or more viscosity modifiers, one or more releasing agents, one or more oxidants, one or more organic compounds. The electrowinning circuit may comprise a pump and / or adjustable control valve configured for introducing process water to the mixing or storage tank. The electrowinning circuit may comprise a rectifier configured to reverse polarity of the anode and cathode for performing a reverse polarity sequence and / or configured for at least temporarily changing the charge of the cathode in the electrowinning cell. The electrowinning circuit may comprise an energizable ultrasonic transducer provided to the electrowinning cell configured for mechanically removing the precious metal from the cathode using sound waves. The electrowinning circuit may comprise means for delivering the electrowinning solution from the mixing or storage tank to the electrowinning cell. In some embodiments the mixing or storage tank may comprise or be provided as a barren solution return tank 5, without limitation.

[0025] An electrowinning cell 100 according to some embodiments may comprise a tank 111. The tank 111 may be optionally supported by, coupled to, form a portion of, be surrounded by, and / or be at least partially integrated with a frame 14. For example, as depicted, a frame 14 may comprise a forklift engageable “skid” with surrounding skeletal frame members for supporting piping and / or for mounting various components of the electrowinning cell 100. The electrowinning cell 100 may comprise an upper chassis 112. The upper chassis 112 may comprise an electrode mounting system 106. The electrode mounting system 106 may be configured to hold at least one electrode 121 , 122. The electrowinning cell may be characterized in that it comprises a include a novel lifting system 107. The lifting system 107 may be configured to raise and lower the upper chassis 112 in relation to the frame 14 and / or the tank 111 (e.g., without manual intervention or involvement). The lifting system 107 may be configured to at least temporarily remove portions of the at least one electrode 121 , 122 (and / or portions of a wash system 108) from submersion within the tank 111. In some embodiments, the electrowinning cell 100 may comprise a wash system 108. The wash system 108 may be provided to the tank 111. Alternatively, as depicted in FIGS 12a-c, portions of the wash system 108 may be provided to a portion 112a, 112b of an upper chassis 112, without limitation.

[0026] In some embodiments, the wash system 108 may comprise at least one manifold 115. In some embodiments, the wash system 108 may comprise two manifolds 115, for example, with each manifold 115 being provided on opposite sides of the tank 111 . In some embodiments, where there are a plurality of manifolds 115, the manifolds 115 may be in fluid communication with each other via a branch / splitter 120 extending between and fluidly connecting the two manifolds 115 together.

[0027] In some embodiments, the wash system 108 may comprise one or more spray bars 147. The one or more spray bars 147 may span into and / or substantially across one or more portions of the tank 111. In some embodiments, the wash system 108 may comprise one or more feed pipes 116. The one or more feed pipes 116 may be rigid or flexible, without limitation. In some embodiments, the wash system 108 may comprise one or more spray bar inlets 117. For example, as shown, the inlets 117 may enter from a side portion of the tank 111. In some embodiments, the wash system 108 may be configured to receive a washing fluid cleaning medium. The washing fluid cleaning medium may be received within one or more manifolds 115, and may be distributed to one or more spray bars 147 (e.g., spanning into and / or substantially across one or more portions of the tank (111)). The washing fluid cleaning medium may be emitted through one or more orifices 149 in the one or more spray bars 147, without limitation.

[0028] In some embodiments, each of the one or more spray bars 147 may comprise a closed end, capped end, or endcap 163. In some embodiments, a plurality of spray bars 147 may be employed. A plurality of spray bars 147 may be fed by the same manifold 115. In some embodiments, a plurality of spray bars may be employed 147, wherein adjacent spray bars 147 may be fed by different manifolds 115. In some embodiments, the spray bars 147 may be provided in an alternating arrangement. For example, a closed end, capped end, or endcap 163 of a first spray bar 147 may be located on a first side of the tank 111 - wherein closed ends, capped ends, or endcaps 163 of second and third spray bars 147 provided immediately adjacent to (i.e., “sandwiching” the first spray bar 147) may be located on a second side of the tank 111 which is opposite to and / or situated across from the first side of the tank 111.

[0029] In some embodiments, the wash system (108) may be configured to receive and / or deliver filtered barren solution as a washing fluid cleaning medium to clean the at least one electrode (121 , 122). In some embodiments, the wash system (108) may be configured to receive and deliver plant water (e.g., process water, reclaimed water, freshwater, potable water, recycled water, without limitation) as a washing fluid cleaning medium to clean at least one electrode (121 , 122). The washing fluid cleaning medium can cycle between different types of washing fluid cleaning mediums, without limitation. In some embodiments, the wash system (108) may be supported by the tank (111 ) and / or frame (14). In some embodiments, the wash system (108) may remain stationary with respect to the tank (111) and / or frame (14). In some embodiments, the wash system (108) may move with respect to the tank (111 ) and / or frame (14). In some embodiments, the lifting system (107) may comprise one or more actuators (114). In some embodiments, the one or more actuators (114) may comprise a plurality of actuators (114). In some embodiments, the one or more actuators (114) may comprise a ball screw drive. The ball screw drive may comprise a screw rod (144) protected by a protective sheath or shroud (160), without limitation. In some embodiments, the lifting system (107) may comprise one or more guides (113). In some embodiments, the one or more guides (113) may comprise a plurality of guides (113). In some embodiments, the one or more guides (113) may comprise a guide rod (158). The guide rod (158) may be movable within a guide tube (159). In some embodiments, the guide rod (158) may be connected to the upper chassis (112). The guide tube (159) may be connected to the tank (111 ) and / or the frame (14).

[0030] In some embodiments, the electrode mounting system (106) may comprise an insulative, non-conductive electrode support hanger (123). The electrode support hanger (123) may be configured to hold at least one electrode (121 , 122). The electrode support hanger (123) may comprise at least one receiving portion (154) which is configured to receive and retain at least one enlarged portion (155) of said at least one electrode (121 , 122).

[0031] In some embodiments, the wash system (108) may be configured such that as the lifting system (107) raises and lowers the upper chassis (112) in relation to the frame (14) and / or tank (111 ) to at least temporarily remove portions of the at least one electrode (121 , 122) from submersion within the tank (111 ), the at least one electrode (121 , 122) passes by one or more spray nozzles (148) configured to provide a spray pattern (151 ) of washing fluid cleaning medium to clean the at least one electrode (121 , 122) as it is being raised from submersion within the tank (111) via the lifting system (107).

[0032] In some embodiments, the wash system (108) may comprise one or more spray nozzles (148). The one or more spray nozzles (148) may be provided within the tank (111 ). The one or more spray nozzles (148) may be located above a weir (127, 136) or at least adjacent to a weir (127, 136) level and / or above or at least adjacent to an operating fluid level line within the tank (111 ), without limitation. In some embodiments, one or more spray nozzles (148) may be provided to one or more spray bars (147). The one or more spray bars (147) may span substantially across a width of the tank (111 ), e.g., from a first side of the tank (111 ) to a second side of the tank (111 ), or vice-versa, without limitation. In some embodiments, the wash system (108) may comprise one or more spray bars (147) within the tank (111 ). The one or more spray bars (147) may be located above a weir (127, 136) or at least adjacent to a weir (127, 136) level and / or above or at least adjacent to an operating fluid level line within the tank (111 ), without limitation.

[0033] According to some embodiments, an electrowinning cell (100) may comprise a tank (111 ). The tank (111 ) may be supported by, may be coupled to, may form a portion of, may be surrounded by, and / or may be at least partially integrated with a frame (14), without limitation. The electrowinning cell (100) may be characterized in that it comprises a wash system (108) configured to clean at least one electrode (121 , 122) within the tank (111 ) (e.g., without manual intervention or involvement).

[0034] In some embodiments, the wash system (108) may be configured to receive and deliver filtered barren solution as a washing fluid cleaning medium to clean the at least one electrode (121 , 122). In some embodiments, the wash system (108) may be configured to receive and deliver plant water (e.g., process water, reclaimed water, freshwater, potable water, recycled water, without limitation) as a washing fluid cleaning medium to clean at least one electrode (121 , 122). The washing fluid cleaning medium may change between different types of washing fluid cleaning mediums during operation, without limitation.

[0035] In some embodiments, the electrowinning cell (100) may comprise an upper chassis (112). The upper chassis (112) may comprise an electrode mounting system (106) configured to hold at least one electrode (121 , 122). The electrowinning cell (100) may comprise a lifting system (107), which may be configured to raise and lower the upper chassis (112) in relation to the frame (14) and / or tank (111 ) to at least temporarily remove portions of the at least one electrode (121 , 122) from submersion within the tank (111). The upper chassis (112) may comprise a split upper chassis comprising two independently indexable portions (112a, 112b) as suggested in FIGS. 28a-c. As such, one portion (112a) of the upper chassis (112) may comprise a movable wash system (108), and another portion (112b) of the upper chassis (112) may comprise the electrode mounting system (106), without limitation.

[0036] In some embodiments, the wash system (108) may comprise one or more spray bars (147). Each spray bar (147) may comprise one or more spray nozzles (148). In some embodiments, the wash system (108) may be provided to the tank (111). In some embodiments, the wash system (108) may comprise at least one manifold (115), at least one feed pipe (116), and / or at least one spray bar inlet (117) for supplying the one or more spray bars (147) with a washing fluid cleaning medium. The washing fluid cleaning medium may comprise filtered barren solution and / or plant water (e.g., process water, reclaimed water, freshwater, potable water, recycled water, without limitation).

[0037] A novel electrowinning system (1) is also disclosed. Embodiments of the electrowinning system (1 ) may comprise a first skid (2), a second skid (3), and a third skid (4). The first skid (2) may be configured for receiving pregnant leach solution from an upstream (e.g., “customer”) process, and / or configured for delivering the same to the second skid (3). The second skid (3) may comprise an electrowinning cell (100) according to the above described embodiments. In some embodiments, the first skid (2) may comprise a filter (11) (e.g. a canister filter) which may be configured for filtering barren solution received from the third skid (4). The first skid (2) may comprise a pump (10) which may be configured for moving product / sludge from the electrowinning cell (100) of the second skid (3). The same pump (10) may be used to convey solids leaving a barren solution return tank (5) provided to the third skid (4).

[0038] In some embodiments, the first skid (2) may be configured to deliver filtered barren solution and / or plant water (e.g., process water, reclaimed water, freshwater, potable water, recycled water, without limitation) to the second skid (3). For example, in some embodiments, the first skid (2) may be configured to deliver filtered barren solution to a wash system (108) of the electrowinning cell (100) within the second skid (3).

[0039] In some embodiments, the third skid (4) may comprise a barren solution tank (5). The barren solution tank (5) may have a sloped floor leading to a solids return (7). The solids return (7) may connect to a sludge / product discharge (130) at a second junction (166). The sludge / product discharge (130) may be provided to the second skid (3) and fluidly communicate with the electrowinning cell (100) in the second skid (3). In some embodiments, the sludge / product discharge (130) may be configured to communicate with a decant (9). The decant (9) may extend from a tank (111) portion of the electrowinning cell (100) in the second skid (3). Communication between the decant (9) and sludge / product discharge (130) may occur at a first junction (165).

[0040] In some embodiments, the third skid (4) may comprise a barren solution tank (5) having an outlet (18). The outlet (18) may communicate with a three-way valve (16) (or three separately-controllable control valves) configured to divert barren solution leaving the barren solution tank (5) to one (or more) of:

[0041] -a client return;

[0042] -a tank (111 ) of the electrowinning cell (100) of the second skid (3) (for example, via piping supplied to or extending across the first skid (2));

[0043] -a filter (11 ) in the first skid (2), and then subsequently from the filter (11 ) in the first skid (2) to a wash system (108) of the electrowinning cell (100) in the second skid (3).

[0044] It should be understood that in some embodiments, the electrowinning system (1 ) may comprise any one or more of the referenced and numbered technical features described and / or shown in the figures, in any combination.

[0045] Further disclosed, is a method of electrowinning. The method may be characterized in that it comprises the step of providing an electrowinning cell (100) or system (1 ) according to any of the above-described embodiments. The method may be characterized in that it comprises the step of i.) mechanically raising an upper chassis (112) and / or electrode mounting system (106) to at least partially remove at least one electrode (121 , 122) from submersion within the tank (111 ) using a lifting system (107) - for example, a lifting system (107) extending between and movably connecting the frame (14) and upper chassis (112). The method may be characterized in that it comprises the step of ii.) washing the at least one electrode (121 , 122) using a wash system (108) provided to the electrowinning cell (100). According to some embodiments, the above steps of i.) mechanically raising and ii.) washing the at least one electrode (121 , 122) are both performed (e.g., in sequence or at some point during operation). According to some embodiments, the above steps of i.) mechanically raising and ii.) washing the at least one electrode (121 , 122) may be both performed simultaneously.

[0046] According to some embodiments, the step of ii.) washing the at least one electrode using a washing system (108) may comprise running filtered barren solution through one or more orifices (149) (e.g., of a nozzle 148 or spray bar 247). The one or more orifices (149) may be in fluid communication with a manifold (115). The manifold (115) may be supplied with said filtered barren solution (e.g., from a filter 11 ). Accordingly, the method may comprise steps of delivering barren solution from a barren solution return tank 5 to a filter 11 , and / or filtering barren solution before the step of running filtered barren solution through one or more orifices (149).

[0047] In some embodiments, the step of ii.) washing the at least one electrode using a washing system (108) may comprise the step of spraying the at least one electrode (121 , 122) within an upper portion of the tank (111 ), for example, at a location within the tank (111) that is above an operating fluid level line within the tank (111) and / or above a weir (127, 136) of the electrowinning cell (100), without limitation.

[0048] It should be understood that in some embodiments, the step of washing the at least one electrode (121 ,122) may alternatively, or in addition, be performed in-situ, or “within” the tank (111) such that the one or more orifices (149) delivering filtered barren solution are submerged within the tank (i.e., within a lower portion of the tank (111 ), for example, at a location within the tank (111) that is below an operating fluid level line within the tank

[0049] (111) and / or below a weir (127, 136) of the electrowinning cell (100), without limitation.

[0050] In some embodiments, an electrowinning cell (100), electrowinning system (1 ), or method of electrowinning may comprise or utilize a wash system (108) which remains substantially static in relation to the tank (111 ) and / or frame (14), for example, as depicted in the embodiments shown in FIGS. 1 -27.

[0051] However, it should further be understood that an electrowinning cell (100), electrowinning system (1 ), or method of electrowinning according to embodiments of the invention may have at least a portion of a wash system (108) which is dynamic. For example, as depicted in the embodiment of FIGS. 28a-c, at least a portion of the wash system (108) employed or utilized may be configured to move in relation to the tank (111) and / or frame (14), without limitation. This may be achieved by using a plurality of lifting systems (107) each independently controlling raising / lowering of two separate portions (112a, 112b) of a split upper chassis (112), without limitation. In such embodiments, portions of the wash system (108) may be provided to one of portions (112a, 112b) of the split upper chassis (112), and the electrode mounting system (106) - including electrode support hanger (123) may be provided to the other one of the portions (112a, 112b) of the split upper chassis (112), without limitation.

[0052] In some embodiments, an electrowinning cell (100) may comprise an upper chassis

[0053] (112) having an electrode support hanger (123) attached thereto. The electrode support hanger (123) may be configured to support and / or hold one or more electrodes (121 , 122) in at least a vertical direction. The electrode support hanger (123) may comprise at least one receiving portion (154). The at least one receiving portion (154) may be configured to receive a respective at least one enlarged portion (155) provided to an upper portion of an electrode (121 , 122). The at least one receiving portion (154) may be configured to support the electrode (121 , 122) from above, for example, such that the electrode (121 ,

[0054] 122) hangs from the electrode support hanger (123), without limitation. In some embodiments, the at least one receiving portion (154) may be configured to extend substantially horizontally across the electrode support hanger (123). In some embodiments, the at least one receiving portion (154) may be configured to have a lower opening for providing clearance for an upper electrode extension portion (140). The at least one receiving portion (154) may be configured to such that it is configured to receive a respective at least one enlarged portion (155) of an electrode (121 , 122) transversely, for example, substantially horizontally, in a side-to-side or lateral sliding motion between the respective at least one enlarged portion (155) of the electrode (121 , 122), relative to the electrode support hanger (123). Such embodiments of an electrowinning cell (100) may comprise a wash system (108) and / or a lifting system (107) for raising and lowering the upper chassis (112) in relation to a tank (111 ) and / or frame (14). Such embodiments may include at least one inlet (117) provided to the wash system (108) which communicates with a tank (111 ). The at least one inlet (117) may be provided with a grommet. The at least one inlet (117) may be sized with a minimum inner diameter which is greater than a maximum outer diameter of a spray bar (147) that is provided with or without nozzles (148). In this regard, the spray bar (147) can be removed from and / or inserted into the tank (111 ) laterally, through a sidewall of the tank (111 ) and / or through the at least one inlet (117), without significant interference or binding between the spray bar (147) and the at least one inlet (117) or sidewall of the tank (111 ).

[0055] Washing mechanisms or features of washing mechanisms such as those depicted in Applicant’s WO2021094978A1 , WO2016179408A1 , and / or WO2015127366A2 (which are each hereby incorporated by reference in their entirety as if fully set forth herein) may be employed to wash between adjacent electrodes (121 , 122), without limitation.

[0056] In some embodiments, an electrowinning cell (100) may comprise a current and / or voltage measuring device (187). The current and / or voltage measuring device (187) may be configured to output a separate signal or readout for each electrode (121 , 122) in the electrowinning cell (100), without limitation. For example, the current and / or voltage measuring device (187) may be configured to output a separate signal or readout for each cathode (122) in the electrowinning cell (100), without limitation. As another example, the current and / or voltage measuring device (187) may be configured to output a separate signal or readout for each anode (121 ) in the electrowinning cell (100), without limitation. In some embodiments, the current and / or voltage measuring device (187) may be connected to an integrated control panel (180), without limitation. The integrated control panel (180) may be automated in preferred embodiments, without limitation.

[0057] The control panel (180) may be configured to directly or indirectly control the current and or / voltage delivered to one or more electrodes, cathodes (122), and / or anodes (121 ), without limitation. The control panel (180) may be configured to directly or indirectly receive and / or process each signal or readout, without limitation.

[0058] The control panel (180) may comprise a graphical user interface GUI (181 ) or equivalent human machine interface (HMI), without limitation. The graphical user interface (181 ) may be configured to display each separate signal or readout associated with each electrode, anode (121 ), or cathode (122) in the electrowinning cell (100), for example, as depicted in FIG. 31 , without limitation.

[0059] In some embodiments, an electrowinning cell (100) may be configured such that one or more of the electrodes (121 , 122) therein are configured to slide-in and / or slide-out of an electrode support hanger (123), for example, in a substantially lateral, sideways, horizontal, or transverse direction with respect to the electrode support hanger (123) of the electrowinning cell (100), without limitation. In some embodiments, the one or more electrodes (121 , 122) in the electrowinning cell (100) may each comprise an upper enlarged portion (155), for example, which is configured (e.g., shaped and / or sized) to slide into and / or remain within respective receiving portions (154) of the electrode support hanger (123), without limitation. The upper enlarged portion (155) may enable the one or more electrodes (121 , 122) to hang from the electrode support hanger (123), for example, while supporting their own weight and the weight of electrowinning product accumulating or loading thereon, without limitation. In some embodiments, an electrowinning cell (100) may comprise a feed distributor (167). The feed distributor (167) may be located in the feed end and / or the discharge end of the electrowinning cell (100), without limitation. In some cases, a plurality of feed distributors (167) may be provided to an electrowinning cell (100). In such cases, it may be preferrable to have a first feed distributor (167) located on an inlet side of the electrowinning cell (100) and another feed distributor (167) located on an outlet side of the electrowinning cell to diffuse fluid flow or flux through the tank (111 ), without limitation.

[0060] A feed distributor (167) where used herein may be provided as a substantially planar dispersion baffle or flow-dispersing baffle. It may comprise a number of openings which are sized, shaped, distributed, adapted and / or configured to disperse fluids uniformly across a cross-section of the tank (111 ) of the electrowinning cell (100), without limitation. It should be understood that non-planar baffles including ribbed, undulating, or corrugated baffles are envisaged, without limitation. In some embodiments, the feed distributor (167) may be removable and / or replaceable with another similar feed distributor (167) or a feed distributor (167) having a different configuration of openings (e.g., sizes, shapes, distribution of openings, or the like), without limitation. The number of openings in the feed distributor (167) may be chosen and configured to control and / or optimize a flow rate or flux of electrolyte feed through the tank (111) of the electrowinning cell (100), without limitation.

[0061] In some embodiments, an electrowinning cell (100) may comprise one or more integrated electrode electrical insulators (177, 178), without limitation. In some embodiments, the one or more integrated electrode electrical insulators (177, 178) may comprise one or more flow-restricting baffles (178) which are each configured to protrude downwardly into a sludge collection trough above a sloped floor (129) within the tank (111 ) of the electrowinning cell (100), without limitation. The one or more flow-restricting baffles (178) may, in some embodiments, comprise a triangular shape, or be chevron-shaped, or have edges which are spaced from and / or substantially parallel to the sloped floor (129), without limitation. In some embodiments, the one or more integrated electrode electrical insulators (177, 178) may comprise one or more frame members (177), for example, which are formed of an insulated material. The one or more frame members (177) may be configured to surround or be arranged proximate peripheral edge portions of one or more electrodes (121 , 122) within the tank (111 ) of the electrowinning cell (100), without limitation. The integrated frame members (177) and baffles (178) may be integral with one another in some embodiments, without limitation. In other conceivable embodiments, the integrated frame members (177) and baffles (178) may be separable from one another, without limitation.

[0062] In some embodiments, an electrowinning cell (100) may comprise an integrated discharge cleaning nozzle (138). The integrated discharge cleaning nozzle (138) may be configured to receive and deliver a fluid flow to a portion of the tank (111 ) of the electrowinning cell (100). The integrated discharge cleaning nozzle (138) may be configured to move sludge (43) or other solids down a sloped floor (129) within the tank (111 ), without limitation. In some embodiments, a similar integrated discharge cleaning nozzle (138) may be present in the barren solution return tank (5), without limitation.

[0063] In some embodiments, an electrowinning cell (100) may comprise a plurality of independent lifting systems (107) and / or a plurality of independent wash systems (108), without limitation. The electrowinning cell (100) may be fabricated from an existing (i.e., “brownfield” installation unit) using one or more retrofit kits. In some embodiments, the existing electrowinning cell may comprise one or multiple electrowinning chambers within its tank (111), without limitation.

[0064] An electrowinning system (1) is further disclosed. The electrowinning system may comprise an electrowinning cell (100) as described above, and may further include an integrated and / or automated control panel (180) which may be directly or indirectly connected to: the electrowinning cell (100); a cell rectifier (183) communicating with the electrowinning cell (100); and / or a cell rectifier (183) connected to the electrowinning cell (100), without limitation.

[0065] In some embodiments, the integrated and / or automated control panel (180) may be configured to provide a plurality of separate inputs and / or receive a plurality of separate signal outputs from a respective number of electrodes (121 , 122) in the electrowinning cell (100), for example, via the cell rectifier (183), without limitation.

[0066] In some embodiments, an electrowinning system (1) may comprise an electrowinning cell (100) as previously described above, in conjunction with an integrated process blower or exhaust fan (52), which may be configured to expel exhaust from the electrowinning cell (100), for example, via a vent (8), without limitation. In some embodiments, an electrowinning system (1 ) may comprise an exhaust damper (53). The exhaust damper (53) may fluidly communicate with the vent (8), without limitation. In some embodiments, the blower or exhaust fan (52) and / or the damper (53) may have at least two operating set points. The at least two operating set points may be controllable, for example, by an integrated and / or automated control panel (180) in the electrowinning system (1 ), without limitation.

[0067] In some embodiments, the blower or exhaust fan (52) may comprise a flow measuring device (187). The blower or exhaust fan (52) may be configured to be directly or indirectly controlled using signal outputs from a flow measuring device (187) in the electrowinning system (1 ), without limitation. In some embodiments, the blower or exhaust fan (52) may be controllable by a Variable Frequency Drive (VFD), for example, to modulate extraction of off gas (41 ), without limitation.

[0068] In some embodiments, an electrowinning system (1) may comprise an electrowinning cell (100) according to any one of the aforementioned embodiments, as well as a sludge removal system. The sludge removal system may be configured to remove sludge from the electrowinning tank (111 ) of the electrowinning cell (100) and / or from the barren solution return tank (5). The sludge removal system may comprise at least one discharge cleaning nozzle (138) and / or at least one spray nozzle (148), without limitation.

[0069] In some embodiments, an electrowinning system (1) may comprise means for electrode (121 , 122) current monitoring and / or trending. For example, a control panel (180) or other portion of the electrowinning system (1 ) may comprise HH and LL current alarms. A current alarm, status indicator, reading / readout, and / or current trend indicator may be provided for one electrode (121 , 122) independently from one or more other electrodes (121 , 122). For example, separate or independent current alarms, status indicators, readings / readouts, and / or current trend indicators may be provided for each electrode (121 , 122) in an electrowinning cell (100), without limitation.

[0070] In some embodiments, an electrowinning cell (100) of the electrowinning system (1 ) may comprise at least one spray nozzle (148) and a discharge cleaning nozzle (138), without limitation. In some embodiments, the barren solution return tank (5) of the electrowinning system (1 ) may comprise at least one discharge cleaning nozzle (138), without limitation.

[0071] A control panel (180) for integrating with and / or automating an electrowinning system (1 ) is also disclosed. The control panel (180) may be used in or in conjunction with an electrowinning system (1 ) comprising an electrowinning cell (100) and a cell rectifier (183). The cell rectifier (183) may be configured for modulating current and / or voltage to the electrowinning cell (100).

[0072] In some embodiments, the control panel (180) comprise a graphical user interface (GUI) or Human Machine Interface (HMI) (181 ). The graphical user interface (181 ) may comprise a display. Visual readout indicia may be provided to, or located on, or depicted by the display. The visual readout indicia may include a plurality of separate current or voltage measurement readings. For example, each of the measurement readings may represent a separate current or voltage signal received from a respective number of electrodes (121 , 122) in the electrowinning cell (100), without limitation. The separate current or voltage signal may be received from the cell rectifier (183), without limitation.

[0073] In some embodiments, the control panel (180) may be configured to control standard (i.e. , normal) polarity and / or reverse polarity current cycles of the current / voltage applied to the electrodes (121 , 122), without limitation. Said differently, current / voltage feeding the electrodes (121 , 122) may be controlled by the control panel (180) and the control panel (180) may be configured to communicate with a rectifier (183) to switch polarity of one or more electrodes (121 , 122) comprising an charge.

[0074] The control panel may be configured to be directly or indirectly connected to: the electrowinning cell (100), a cell rectifier (183) communicating with the electrowinning cell (100), and / or a cell rectifier (183) connected to the electrowinning cell (100), without limitation. In some embodiments, an integrated and / or automated control panel (180) may be configured to provide a plurality of separate inputs to and / or receive a plurality of separate signal outputs from a respective number of electrodes (121 , 122) in the electrowinning cell (100), for example, via the cell rectifier (183), without limitation.

[0075] An integrated process blower or exhaust fan (52) is additionally disclosed. The integrated process blower or exhaust fan (52) may be configured to expel exhaust from an electrowinning cell (100) of an electrowinning system (1 ). The integrated process blower or exhaust fan (52) may comprise a flow measuring device (187) connectable to an electrowinning cell (100), without limitation. The integrated process blower or exhaust fan (52) may communicate with a flow measuring device (187) which is non-integral to the integrated process blower or exhaust fan (52). For example, the integrated process blower or exhaust fan (52) may communicate with one or more flow measuring devices (187) measuring off gas (41 ) being transported through a vent (8). Accordingly, an integrated process blower or exhaust fan (52) may not comprise a flow measuring device (187), but rather, it may communicate with one or more remotely- or proximately- positioned flow measuring devices (187) which are spaced from the integrated process blower or exhaust fan (52), without limitation.

[0076] The integrated process blower or exhaust fan (52) may have at least two operating set points. These at least two operating set points may be configured to be controlled by a control panel (180), such as an integrated and / or automated control panel (180), without limitation.

[0077] In some embodiments, the integrated process blower or exhaust fan (52) may be configured to communicate with a vent (8) from an electrowinning cell (100). The vent (8) may be configured to deliver off gas (41) from the electrowinning cell (100), without limitation. In some embodiments, the integrated process blower or exhaust fan (52) may be configured to communicate with a vent (8) from a barren solution return tank (5) communicating with the electrowinning cell (100). The vent (8) may be configured to deliver off gas (41) from the barren solution return tank (5), without limitation. In some embodiments, the integrated process blower or exhaust fan (52) may be configured to communicate with a vent (8) extending from both a barren solution return tank (5) and an electrowinning cell (100), without limitation.

[0078] The integrated process blower or exhaust fan (52) may be configured to communicate with, provide off gas (41 ) to, or receive off gas (41) from a damper (53), without limitation. The damper (53) may be configured to modulate flow of off gas (41) passing through a vent (8), for example, a vent (8) that delivers off gas (41) from an electrowinning cell (100) and / or from a barren solution return tank (5), without limitation. An integrated process damper (53), where shown or described herein, may be configured to control expulsion of off gas (41) from an electrowinning cell (100) and / or from a barren solution return tank (5) of an electrowinning system (1 ). The integrated process damper (53) may comprise a flow measuring device (187). The flow measuring device (187) may be connectable to an electrowinning cell (100), without limitation.

[0079] The integrated process damper (53) may have at least two operating set points. The at least two operating set points may be configured to be controlled by a control panel (180), such as an integrated and / or automated control panel (180), without limitation. The integrated process damper (53) may be configured to fluidly communicate with, provide off gas (41) to, or receive off gas (41) from an integrated process blower or exhaust fan (52), without limitation. In some embodiments, the integrated process damper (53) may be configured to modulate a flow of off gas (41 ) passing through a vent (8), for example, a vent (8) that delivers off gas (41) from the electrowinning cell (100) and / or from a barren solution return tank (5), without limitation.

[0080] A retrofit kit for an electrowinning cell (100) is also disclosed. In some embodiments, the retrofit kit may comprise one or more components of a lifting system (107). The lifting system (107) may be configured to raise and lower an upper chassis (112) in relation to a frame (14) and / or tank (111 ) of an electrowinning cell (100). The lifting system (107) may be configured to at least temporarily remove portions of at least one electrode (121 , 122) from submersion within a tank (111 ) of an electrowinning cell (100). The one or more components of the retrofit kit may be configured to be installable onto and / or may be directly or indirectly integratable with a tank (111) of an electrowinning cell (100). In some embodiments, the one or more components of the retrofit kit may, for example, be selected from the group consisting of: an actuator (114), a guide (113), a drive motor (126), a movable upper chassis (112), a first part (112a) of a split movable upper chassis (112), a second part (112b) of a split movable upper chassis (112), a drive axle (142), a transmission (141 ), a gearbox (143), a screw rod (144), a ball screw drive (145), a drive coupling (146), without limitation. According to some embodiments, a method of retrofitting an electrowinning cell (100) may be performed. The method may comprise the step of mounting and / or installing one or more of the components of the retrofit kit. For example, one or more components of a lifting system (107) provided by the retrofit kit may be used to convert an existing (e.g., brownfield) electrowinning cell (100), or may be used to service or replace a component of an electrowinning cell (100) having a lifting system (107) provided thereto, without limitation.

[0081] A retrofit kit for an electrowinning cell (100) according to some embodiments, may comprise one or more components of a wash system (108). The wash system (108) may be configured for use with an electrowinning cell (100), and components thereof may be intended to be installed directly or indirectly onto a an electrowinning cell (100), for example, onto a sidewall portion of a tank (111 ) of an electrowinning cell (100), without limitation. The wash system (108) may be configured to clean at least one electrode (121 , 122) within a tank (111 ) of an electrowinning cell (100). The one or more components of the retrofit kit may be configured to be installable onto and / or directly or indirectly integrated with a tank (111 ) of the electrowinning cell (100), without limitation. The one or more components of the retrofit kit may, for example, be selected from the group consisting of: a spray bar (147), a manifold (115), a feed pipe (116), a spray bar inlet (117), an end cap (163), a nozzle (150), filter outlet piping (35), a filter (11 ), without limitation.

[0082] A method of retrofitting an electrowinning cell (100) may comprise forming one or more holes into a sidewall portion of a tank (111 ) of the electrowinning cell (100). The method may include mounting and / or installing the one or more components of the wash system (108) that are provided within the retrofit kit, without limitation.

[0083] A method of retrofitting an electrowinning cell (100) may comprise providing one or more lifting systems (107) and / or one or more wash systems (108) to an electrowinning cell (100), for example, an electrowinning cell (100) that lacks a wash system (108) and / or lacks a lifting system (107) in accordance with embodiments of the invention. The method of retrofitting may comprise replacing one or more lifting systems (107) and / or one or more wash systems (108) to an electrowinning cell (100) according to embodiments disclosed herein, without limitation. Retrofitting of an electrowinning cell (100) may be accomplished through the use of a retrofit kit described above, without limitation.

[0084] An electrode (121 ,122) for an electrowinning cell (100), such as an anode (121 ) or a cathode (122) is further disclosed. The electrode (121 , 122) may comprise an electrically conductive, generally planar central metallic portion. The electrode (121 , 122) may comprise one or more integrated electrode electrical insulators (177, 178). The one or more integrated electrode electrical insulators (177, 178) may comprise one or more flow-restricting baffles (178). The one or more flow-restricting baffles (178) may be configured to protrude downwardly into a sludge collection trough. The one or more flow- restricting baffles (178) may be configured to protrude downwardly and remain positioned above a sloped floor (129) within a tank (111 ) of an electrowinning cell (100). According to some embodiments, the one or more flow-restricting baffles (178) may be triangular, chevron- shaped, or have edges which are configured to be spaced from and / or substantially parallel to a sloped floor (129) of an electrowinning cell (100). The one or more integrated electrode electrical insulators (177, 178) may comprise one or more frame members (177). The one or more frame members (177) may be formed of an insulated material. The one or more frame members (177) may be configured to surround the electrically conductive generally planar central metallic portion. The one or more frame members (177) may be configured to be arranged proximate peripheral edge portions of the electrically conductive generally planar central metallic portion, without limitation.

[0085] In some embodiments, the integrated frame members (177) and baffles (178) may be configured to be integral with one another. In some embodiments, the integrated frame members (177) and baffles (178) may be configured to be separable from one another. In some embodiments, the electrically conductive generally planar central metallic portion may comprise a wire mesh or plate structure, without limitation.

[0086] In some embodiments, the electrode (121 ,122) may comprise an enlarged portion (155). The enlarged portion (155) may be provided adjacent an upper portion of the electrode (121 ,122), for example, at a location above the electrically conductive generally planar central metallic portion, without limitation. The enlarged portion (155) may be configured to be received and / or retained within a complimentary receiving portion (154) of an electrode support hanger (123) of an electrowinning cell (100), without limitation. In some embodiments, the enlarged portion (155) may be configured to be received in a receiving portion (154) of an electrode support hanger (123) transversely, substantially horizontally, or in a side-to-side or lateral sliding motion, without limitation. The enlarged portion (155) may extend across the entire upper end of the electrode (121 , 122) continuously, or a plurality of enlarged portions (155) may extend across portions of the upper end of the electrode (121 , 122) in an interrupted fashion.

[0087] Further features and advantages of the present invention will become apparent from the following detailed description.

[0088] BRIEF DESCRIPTION OF THE DRAWINGS

[0089] By way of example only, preferred embodiments of the invention will be described more fully hereinafter with reference to the accompanying figures.

[0090] FIGS. 1 -3 depict isometric, side profile, and top views, respectively, of a first non- limiting embodiment of an electrowinning system 1 within the scope of the invention.

[0091] FIG. 4 depicts a front / side plan view of a second skid 3 within the system 1 shown in FIGS. 1 -3, namely, an electrowinning cell 100 according to some non-limiting embodiments of the invention.

[0092] FIG. 5 is an alternative isometric view of FIG. 4.

[0093] FIG. 6 is a partial cutaway view of FIG. 5.

[0094] FIG. 7 is an alternative isometric view of FIG. 6.

[0095] FIG. 8 is a close-up view of the section depicted in FIG. 6 more clearly depicting features of an electrowinning cell 100 near an electrode mounting system 106. FIG. 9 is a close-up view of a portion of FIG. 8 more clearly depicting means for washing (e.g., components of a wash system 108 according to certain non-limiting embodiments).

[0096] FIG. 10 is an alternative cross-sectional view of the electrowinning cell 100 of FIGS. 1 -9, showing a top portion removed.

[0097] FIG. 11 is another cross-sectional view through FIG. 9 taken from a deeper transverse plane than the cross-sectional view depicted in FIG. 10. This deeper cross- sectional view showing a top portion of the electrowinning cell 100 removed for clarity more clearly depicts portions of a wash system 108 according to some non-limiting embodiments.

[0098] FIG. 12 is a close-up portion of FIG. 11 .

[0099] FIG. 13 is a top plan view of FIGS. 11 (looking down from above).

[0100] FIG. 14 shows a lifting system 107 according to some embodiments in a first position comprising a retracted (e.g., lowered) position. Shown, is the lifting system 107 depicted in FIGS. 1 -13, with other components of the second skid 3 removed for clarity.

[0101] FIG. 15 is a close-up portion of FIG. 14.

[0102] FIG. 16 shows the lifting system 107 of FIG. 14 in a second position comprising a deployed (e.g., extended or raised) position. The wash system 108 may be activated just before and / or as the upper chassis 112 is raised.

[0103] FIG. 17 shows an alternative non-limiting embodiment of an electrowinning cell 100 in a first configuration with its lifting system 107 in a first position comprising a retracted (e.g., lowered) position.

[0104] FIG. 18 shows the electrowinning cell of FIG. 17 in a second configuration with its lifting system 107 in a second position comprising a deployed (e.g., extended or raised) position, wherein electrodes 121 , 122 are at least partially removed from the tank 111 of the electrowinning cell. The wash system 108 may clean the electrodes 121 , 122 just prior to and / or as they are raised from the tank 111.

[0105] FIGS. 19 and 20 are alternative side cutaway views of the electrowinning cell 100 depicted in FIGS. 1 -17.

[0106] FIG. 21 is a close-up portion of FIG. 20

[0107] FIG. 22 is a front side plan view of an alternative non-limiting embodiment of an electrowinning system 1 in accordance with the invention.

[0108] FIG. 23 is an isometric view of the system 1 depicted in FIG. 22.

[0109] FIG. 24 is a partial cut-away view of FIG. 23.

[0110] FIG. 25 depicts a close-up view of the left portion (third skid 4) of the system 1 shown in FIG. 23.

[0111] FIG. 26 depicts a close-up view of the right portion (first skid 2) of the system 1 shown in FIG. 23.

[0112] FIG. 27 shows a non-limiting process flow diagram (PFD) according to some non- limiting embodiments of the invention. FIGS. 28a-c depict yet another non-limiting embodiment of an electrowinning cell 100 comprising a split upper chassis 112 comprising separate parts 112a, 112b and lifting system

[0113] 107 which is configured for independently raising and lowering electrodes 121 , 122 separately from raising and lowering portions of a wash system 108. As depicted, portions of the wash system 108 may be configured to be dynamic or “move” relative to the tank 111 and / or the electrodes 121 , 122, without limitation.

[0114] FIGS. 29 and 30 depict photographs of electrowinning cells according to the prior art. As shown, covers are hinged and can be opened and closed but they lack a wash system

[0115] 108 and / or a lifting system 107 according to embodiments of the invention. These are perfect examples of electrowinning cells that could be reworked using one or more retrofit kits according to embodiments, as will be further appreciated.

[0116] FIG. 31 shows a representative non-limiting display output of a control panel equipped with a graphical user interface or human machine interface. Indicia depicted on the display output signifies that individual current / voltage readings for one or more electrodes 121 , 122 may be displayed. This is made possible by apparatus within an electrowinning system according to embodiments, which enables separate signals to be conveyed between the electrowinning cell 100, rectifier 183, and / or control unit 180.

[0117] FIG. 32 depicts an electrowinning system 1 according to embodiments of the invention showing a rectifier and control panel 180.

[0118] FIGS. 33 and 34 depict schematically, various configurations of an electrowinning system 1 according to non-limiting embodiments.

[0119] DETAILED DESCRIPTION OF THE DRAWINGS

[0120] Embodiments of an apparatus and method for controlling hard deposits on cathodes (and / or anodes) during the electrowinning of precious metals are disclosed.

[0121] In the method, the step of temporarily increasing the current density may be utilized during the electrowinning process to produce a softer deposit and / or to soften an existing hard deposit. In some embodiments, the current density and / or a duration of change in the current density may vary as function of time, rate of plating, softness of deposits, and / or concentration of precious metals in the electrowinning feed, without limitation.

[0122] In addition to this, or in lieu of this, a step of increasing a concentration of sodium cyanide may be utilized during the electrowinning process to achieve a softer deposit and / or to soften an existing hard deposit. In some embodiments, the concentration of sodium cyanide may vary as function of time, rate of plating, softness of deposits, and / or concentration of precious metals in the electrowinning feed, without limitation.

[0123] In addition to, or in lieu of the above, the step of introducing a lixiviant additive comprising an organic compound, a surface modifier, a viscosity modifier, a wetting agent, a releasing agent, or a soft metal (e.g., lead) may be utilized during the electrowinning process, to produce a softer deposit and / or to help soften hard precious metal deposits which may have already formed on electrowinning cathodes or anodes, without limitation. The composition of the additive may be adjusted during the electrowinning process. The amount of the additive added to the electrowinning cell 100 (or a separate vessel such as a mixing or storage tank or barren solution return tank 5) may be varied over time. The additive may be introduced to the electrowinning process periodically. In some embodiments, the amount, duration, and / or composition of the additive introduced may vary as function of concentration of precious metal content in the electrowinning feed, without limitation.

[0124] Mechanical cleaning means may be optionally provided to an electrowinning cell. The mechanical cleaning means may be periodically or continuously used during the electrowinning process. Such means may include an ultrasonic transducer (not depicted), without limitation. The ultrasonic transducer may be continuously or periodically energized, without limitation. The ultrasonic transducer may be energized differently as a function of time and / or “pulsed” to provide waves of varying amplitude or intensity, without limitation.

[0125] For embodiments incorporating such optional means for mechanical cleaning, an ultrasonic cleaning step may be optionally employed in order to aid soft deposit formation and / or hard deposit removal from cathodes / anodes. The cleaning step may be achieved by activating (e.g., energizing) the mechanical cleaning means. In some (preferred) embodiments, such means for mechanical cleaning of electrodes 121 , 122 may include a wash system 108. The wash system 108 may be static (i.e., remain substantially stationary) as depicted in the embodiments found in FIGS. 1 -26 and / or may be dynamic (i.e., move or translate) as depicted in FIGS. 28a-c, without limitation.

[0126] In some embodiments, reverse polarity switching of the anodes and cathodes may be used with the method steps depicted herein. If polarity switching is employed, the step of reversing the polarity of anodes and cathodes within the electrowinning cell is preferably done intermittently and / or periodically (e.g., between normal operation electrowinning plating cycles).

[0127] Embodiments may incorporate one or a combination of process parameters with or without the addition or use of special reagents (i.e., “additives”) in the process to effect soft cathode deposits during electrowinning. Process parameters may include, without limitation: the use of high current density (i.e., greater than 40A / m2) in the electrowinning cell; the use of lixiviant having high sodium cyanide concentrations (e.g., greater than 0.65%, and more preferably between 1 and 4 % by weight.) in the electrowinning cell; the use of one or more lixiviant additives (e.g., a small amount of: one or more soft metals, organic compound(s), wetting agent(s), surface modifier(s), viscosity modifier(s), releasing agent(s)) in the electrowinning cell, the use of increased silver concentrations within the lixiviant by virtue of the addition of Ag(CN)2solution to the electrowinning cell; and / or the optional introduction of mechanical waves or vibrations to the electrowinning cell for cleaning cathodes during the electrowinning process. Alternative mechanical cleaning method steps are envisaged. Though mechanical cleaning is preferably induced via high pressure washing (via wash system 108), other mechanical means (not depicted) such as ultrasonic emitters or other means for inducing ultrasonic waves within an electrowinning cell (100), cathode and / or anode scrapers or scraping mechanisms, as well as cathode vibrating mechanisms or means for inducing vibration to one or more electrodes 121 , 122 may be employed exclusively, or in combination with one or more of each other, without limitation.

[0128] An electrowinning system 1 comprising an electrowinning cell 100 is described. The electrowinning cell 100 may comprise a pump (not shown) for introducing electrowinning feed from an electrowinning feed tank, a rectifier, and an electrolytic cell comprising alternating anodes and cathodes. However, as depicted in FIG. 27, a pump 51 may be provided upstream of the electrowinning cell 100, for example to a first skid 2, or upstream of the electrowinning system 1 , without limitation.

[0129] The electrowinning cell 100 may optionally comprise mechanical cleaning means, such as an ultrasonic transducer (not shown) for assisting with cleaning wire mesh and / or punch plate electrodes. When energized, the ultrasonic transducer produces waves that can assist with removal of electroplated deposits from the wire mesh cathodes. Energizing of such mechanical cleaning means may be done continuously or periodically / intermittently, without limitation. Moreover, amplitude and / or frequency of the ultrasonic waves generated may be adjusted over time. Amplitude and / or frequency of the ultrasonic waves generated may differ during different electrowinning cycles or portions of the electrowinning process, without limitation.

[0130] Alternatively, or in addition to ultrasound, an electrowinning cell 100 according to some embodiments may be provided with mechanical cleaning means such as a wash system 108. Cathodes 122 used in embodiments may be of any type (e.g., including punch plate), but are preferably formed of wire mesh, such as stainless steel wire mesh, without limitation. High pressure washing fluid cleaning medium 39 may be dispersed to one or more electrodes 121 , 122 using the wash system 108. One or more electrodes 121 , 122 may be submerged within a liquid level of a tank 111 of the electrowinning cell 100 during washing (i.e. , “in-situ” wash configuration). In some embodiments, one or more electrodes

[0131] 121 , 122 may be fully or partially removed from the tank 111 and / or raised above a liquid level within the tank 111 of the electrowinning cell 100 during washing, without limitation.

[0132] A blower or an exhaust fan 52 may be used to remove noxious fumes and / or gasses produced by and / or accumulating around the electrowinning cell 100. Barren solution 38 from the electrowinning cell 100 may be removed and recycled as lixiviant or sent to the adsorption circuit (e.g., via “return to client” piping 13), without limitation.

[0133] At the early stages of electrowinning within skid 2 of the system, when cathode / anode surfaces are fresh, clean, and / or new, silver cyanide solution may be temporarily introduced in sufficient concentration to the tank 111 and / or to a barren solution return tank 5, in order to help soften early deposits on the cathodes 122. Sodium cyanide concentration and / or current density may also remain elevated to promote keeping precious metal deposits soft. An optional ultrasonic transducer (not shown) provided to the electrowinning cell 100 can be energized to further discourage hard plating within the electrowinning cell 100. It is anticipated that introduction of Ag(CN)2may help weaken or soften initially-deposited precious metal deposits to aid in precious metal deposit removal from wire mesh cathodes

[0134] 122. The addition and elevated concentration of Ag(CN)2may be maintained throughout the electrowinning process, or, its addition to the electrowinning cell 100 (and / or barren solution return tank 5) may be gradually reduced to lower silver concentration within the electrowinning cell 100. At any time during electrowinning, Ag(CN)2may be intermittently added to the electrowinning cell 100 and / or or to the barren solution return tank 5 (e.g., if it is determined that deposits formations are becoming too hard).

[0135] An electrowinning cell 100 may be accompanied by a mix / storage tank (not shown) and / or a barren solution return tank 5 within the system 1 . The electrowinning cell 100 may operate normally, i.e., consistent with traditional prior art methods, in the sense that electrowinning feed (e.g., pregnant leach solution (PLS) 37) may be pumped to the electrowinning cell 100 from an electrowinning feed tank (not shown), and fumes evacuated through a vent 8 by a blower or an exhaust fan 52. Barren solution 38 may be removed from the electrowinning cell 38 as depicted. Some of the barren solution 38 removed from the electrowinning cell 38 may be transferred to the mix / storage tank and / or the barren solution return tank 5, where additional plant water 40, reagent (e.g., caustic) and / or one or more additive(s) 45, and / or sodium cyanide solution 46 can be introduced to and / or mixed with the barren solution 38 leaving the electrowinning cell 100. A number of pumps 51 and / or control valves may be provided within the system 1 , as needed, to move fluids (e.g., liquids, gasses), slurries, and / or combinations thereof. The composition of the barren solution 38 within the system may change in the mix / storage tank or barren solution return tank 5 such that it may comprise an increased concentration of reagent / additive(s) 45 and / or sodium cyanide 46, without limitation. The resulting solution may be pumped from the mix / storage tank or barren solution return tank 5 back to the electrowinning cell 100 (e.g., via first skid 2), and may, as shown, be combined with the electrowinning feed 37 upstream of a feed inlet 131 to the electrowinning cell 100. A control valve (not shown) may be employed to the circuit 1 to allow adjustment of the ratio of electrowinning feed 37 to recycled barren solution 38 combined therewith. The electrowinning cell 100 may comprise an electrolytic cell having a tank 111 , and a rectifier 168 for adjusting a current applied to spaced anodes 121 and cathodes 122 which may be energized with respective positive or negative charge, in alternating fashion. As with other embodiments, the rectifier 168 may be configured for continuously or intermittently increasing current density. As with other embodiments, the rectifier may be configured to enable reverse-polarity sequences, wherein normally positively-charged anodes 121 are at least temporarily changed to a negative charge, and wherein normally negatively-charged cathodes 122 are at least temporarily changed to a positive charge, without limitation.

[0136] The mix / storage tank or barren solution return tank 5 may comprise a pump and / or valve (not shown) for introducing and / or controlling an amount of plant water 40 delivered thereto, for example, upstream of an inlet 24. The mix / storage tank or barren solution return tank 5 may comprise a pump and / or valve (not shown) for introducing and / or controlling an amount of sodium cyanide (NaCN) delivered thereto, for example, upstream of an inlet 25. The mix / storage tank or barren solution return tank 5 may further comprise a pump and / or valve (not shown) for introducing and / or controlling an amount of a (cleaning) reagent and / or one or more optional additives delivered thereto, for example, upstream of an inlet 26. The cleaning reagent and / or additive may comprise a hard electrowinning deposit remover configured for promoting softening and / or removal of electrowinning hard deposits from the electrodes (121 , 122), without limitation. The plant water 40, cleaning reagent / additive 45, and / or sodium cyanide (NaCN) 46; or, a solution containing one or more of the aforementioned, may be pumped into the electrolytic cell at controlled process conditions which promote releasing of hard deposits and / or softening of the deposits. The deposit- laden anode(s) / cathode(s) may be energized with a charge which is opposite of normal electrowinning cell 100 operation. In this regard, the rectifier 168 may be used to allow the electrowinning cell 100 to undergo a reverse polarity sequence in which a cathode 122 or anode 121 plated with precious metal deposits may be liberated of its deposits through electrolysis. An electrowinning cell 100 may optionally be provided without mechanical cleaning means, although the same may be provided to the electrowinning cell 100 as an option.

[0137] After plating a precious metal on a cathode or anode, a lifting device 107 provided to the electrowinning cell 100 may be used to (automatically) periodically lift and / or at least partially remove one or more cathodes 122 and / or anodes 121 comprising residual deposits containing one or more precious metals (i.e., gold and / or silver) from within the tank 111 .

[0138] In some embodiments, a wheeled transport rack (not shown) may be provided. The transport rack may comprise an electrode support hanger 123 which is similar or identical to that of the electrowinning cell 100. The transport rack may be positioned adjacent the lifted electrodes 121 , 122 and oriented such that at least one respective receiving portion 154 of the electrode support hanger 123 of the electrowinning cell 100 is substantially axially-aligned with at least one respective receiving portion 154 of the electrode support hanger 123 of the transport rack. With the receiving portions 154 of the electrowinning cell 100 and transport rack aligned, at least one electrode 121 , 122 may be slid from a receiving portion 154 of the electrowinning cell 100 into a receiving portion 154 of the transport rack, such that an enlarged portion 155 of the at least one electrode 121 , 122 finds its way into a receiving portion 154 of the electrode support hanger 123 of the transport rack. This may obviate the need for manual hoists, bending over, or manual heavy lifting of electrodes 121 , 122 from the tank 111 of the electrowinning cell 100 as conventionally done. Thus, the appropriately configured transport rack and uniquely-configured electrowinning cell 100 may allow an operator to more easily and ergonomically relocate an electrode 121 , 122 from the electrowinning cell 100 using a transverse motion while the electrowinning cell 100 is configured in a deployed or lifted configuration (e.g., as depicted in FIG. 18. Electrodes 121 , 122 relocated to the transport rack may be wheeled over to a ancillary preparatory station, cleaning station, or separate cathode wash cell (e.g., “cleaning tank”) such as the one described in Applicant’s co-pending U.S. Provisional Patent application Ser. No. 63 / 320,359 filed March 16, 2022, and PCT / IB2023 / 052604 file March 16, 2023 titled “SYSTEM AND METHOD FOR CONTROLLING OR REMOVING HARD DEPOSITS ON ELECTROWINNING CATHODES”), instead of to a smelting operation configured for electrode destruction and recovery by refinement. It should be understood that wire mesh portions of cathodes 122 may be removed and replaced while on the transport rack, without limitation.

[0139] Where and if used, the optional cathode wash cell (not shown) may comprise a pump and / or valve for introducing and / or controlling an amount of plant water delivered thereto. The cathode wash cell may further comprise a pump and / or valve for introducing and / or controlling an amount of a cleaning reagent or additive delivered thereto. The cleaning reagent or additive may comprise a hard electrowinning deposit remover configured for promoting softening and / or removal of electrowinning hard deposits from the wire cathodes / anodes, without limitation. The cathode wash cell may further comprise a rectifier, and an electrolytic cell comprising spaced plates which may be energized with a negative or positive charge in alternating fashion. Plant water 40, the cleaning reagent / additive 45, and sodium cyanide (NaCN) 46; or, a solution containing the same, may be pumped into the electrolytic cell of the cathode wash cell at controlled process conditions which promote releasing of hard deposits and / or softening of residual deposits. The precious metal laden anode / cathodes 121 , 122 may be energized with a charge which is opposite of the original charge of spaced plates in the electrolytic cell of the cathode wash cell. In this regard, such a cathode wash cell may be used as a “reverse polarity tank” in which a cathode 122 or anode 121 plated with difficult or hard-to-remove precious metal deposits may be supplementally processed to further liberate difficult residual deposits through electrolysis, rather than smelting / refining.

[0140] A concentration of sodium cyanide in the optional cathode wash cell may, in some embodiments, be higher than the sodium cyanide concentration within the electrowinning cell 100 from which the cathodes 122 and / or anodes 121 comprising deposits was taken from. A rectifier of the cathode wash cell (which may comprise a shared rectifier 168 of the electrowinning cell 100) may be configured such that current density used in the cathode wash cell may be higher than a current density used in the electrowinning cell 100 from which the cathodes 122 and / or anodes 121 comprising residual deposits was taken from. The combination of higher sodium cyanide concentration and higher current density in the cathode wash cell may present synergistic effects which foster the loosening hard deposits from the cathode(s) / anode(s) 122, 121 therein, and / or assist with softening plated precious metals which cannot be easily removed during the electrowinning process in the second skid 3 of the system 1 . Accordingly, the cathode(s) / anode(s) placed in an optional separate cathode wash cell may be supplementally cleaned, removed from the cathode wash cell, and then re-transferred back to the transfer rack and wheeled back over to the electrowinning cell 100. The transfer rack may then be re-oriented such that the enlarged portions 155 of electrodes 121 , 122 are substantially aligned with receiving portions 154 of the electrode support hanger 123 of the electrowinning cell 100 so that the electrodes 121 , 122 may be slid transversely (e.g., laterally) back into respective receiving portions 154 of the electrowinning cell 100. Accordingly, electrodes 121 , 122 supplementally-cleaned in an ancillary preparatory station, cleaning station, or separate cathode wash cell may be placed back into the operation within the electrowinning cell 100 for recycle / reuse - without the need to sacrificially smelt them in order to recover precious metals entrained therein. A similar process or similar process steps (i.e., concerning transfer of electrodes 121 , 122 from a transfer rack to an electrode support hanger 123 of an electrowinning cell 100) may be employed during installation of new electrodes 121 , 122 into the electrowinning cell 100. Additionally, such a process or steps thereof may be involved in the removal of electrodes 121 , 122 from the electrowinning cell 100 for any reason (e.g., replacement, refurbishment, washing, or retiring of one or more anodes 121 or cathodes 122), without limitation.

[0141] If used, a cathode wash cell may comprise mechanical cleaning means, such as an ultrasonic transducer for assisting with the cathode cleaning wire mesh cathodes. The cathode wash cell may additionally or alternatively employ mechanical cleaning means such as wash system 108 as depicted in the embodiments and shown to be used in conjunction with electrowinning cell 100. The mechanical cleaning means may be dynamic or static, and may involve the use of a lifting system 107 similar to that shown and described for the electrowinning cell 100. When energized, the ultrasonic transducer may produce waves that can assist the removal of hard and / or soft electroplated deposits from electrodes. Energizing of such mechanical cleaning means may be done continuously or periodically / intermittently, without limitation. Moreover, the amplitude and / or frequency of the ultrasonic waves generated may be adjusted (e.g., increased or decreased) over time. Amplitude and / or frequency of the ultrasonic waves generated may differ during different cleaning cycles or during portions of the electrowinning process, without limitation. Other mechanical means for cleaning such as scrapers or mechanical vibration means may be applied, without limitation.

[0142] Though not expressly depicted, a blower or exhaust fan 52 may be used to remove noxious fumes and / or gasses produced by and / or accumulating around the cathode wash cell, without limitation. A vent 8 may be employed to the cathode wash cell. The vent 8 may be similar to the one shown and described for use with the electrowinning cell 100 and may have similar technical features (e.g., venting duct manifold 135 with ports 170), without limitation. Solution may be removed from the cathode wash cell by a pump, and controlled via a control valve. The solution may be recycled directly to the electrowinning cell 100, or to an electrowinning feed tank, without limitation. While not expressly depicted, some or all of the solution from the mix / storage tank or barren solution return tank 5 may be removed and sent to adsorption for recycling as lixiviant, without limitation. Moreover, at least some or all of the solution from the cathode wash cell (if employed) may be combined with the electrowinning feed in a controlled manner upstream of a feed inlet 131 to the electrowinning cell 100.

[0143] Removed solids (i.e., “soft” deposits) which are dislodged from the anode(s) / cathode(s) in the cathode wash cell may fall to the bottom of the electrolytic cell portion of the cathode wash cell. These fallen solids may be pumped from the bottom of the electrolytic cell portion of the cathode wash cell to the electrowinning cell 100 (e.g., via an electrowinning feed tank or barren solution return tank 5 which feeds or at least partially feeds the electrowinning cell 100) - or, it may be removed from the cathode wash cell and sent to another downstream refining process step.

[0144] For any of the embodiments discussed or shown herein, a reverse polarity step (e.g., within the electrowinning cell and / or cathode wash cell) may be employed, without limitation. Adding this step may further assist with dislodging hard-deposited materials containing precious metals from a cathode(s) / anode(s).

[0145] In some preferred embodiments of the electrowinning process (e.g., during the second skid 3), current density may be maintained above approximately 5 A / m2of cathode area, and even more particularly, above approximately 15 A / m2of cathode area. For example, in some preferred embodiments, current density used to soften cathode deposits may be within the range of about 40-200 A / m2of cathode area, without limitation.

[0146] In some preferred embodiments, sodium cyanide concentration may be maintained at all times above approximately ¼ % by weight of electrowinning solution, and even more particularly, above approximately ½ % by weight of electrowinning solution. However, sodium cyanide 46 concentration may temporarily or continuously be elevated above approximately 0.65% by weight. For example, in some preferred embodiments, sodium cyanide concentration used to soften cathode 122 deposits may be kept within the range of about 1 -4% by weight of electrowinning solution, without limitation. In some preferred embodiments, approximately 1 .5% to 3% by weight sodium cyanide concentration of the electrowinning solution may be maintained to clean hard-deposits of precious metals from cathodes 122 (e.g., e.g., approximately 2% by weight sodium cyanide concentration of the electrowinning solution may be maintained). In some preferred embodiments, a lixiviant additive (e.g., introduced with reagent 45 at inlet 25) may be provided to improve softening of precious metals deposited onto cathodes and / or soften existing hard-deposits. The additive may comprise a soft metal, viscosity modifier, a surface modifier, and / or a release agent, without limitation. The additive may comprise a plurality of soft metals, viscosity modifiers, surface modifiers, and / or release agents, without limitation. The additive may comprise a combination of one or more soft metals, viscosity modifiers, surface modifiers, and / or release agents, without limitation. In some non-limiting embodiments, the additive may comprise 1 -10 ppm lead nitrate, without limitation.

[0147] In some preferred embodiments, silver cyanide may be provided as an additive to the process solution (e.g., PLS 46 and / or barren solution 38) to improve softening of deposited precious metals onto cathodes 122 within the electrowinning cell 100. In some non-limiting embodiments, the application of the silver cyanide may be used during initial plating to effectively “pre-coat” wire mesh cathodes with a thin, soft layer of “silver-heavy” deposits prior to and / or during the plating of gold. In this regard, harder deposits of gold may become easier to dislodge from a cathode(s). In some non-limiting embodiments, silver cyanide may be added to an electrowinning solution intermittently. In some embodiments, 50-200 ppm of silver cyanide may be present in the electrowinning solution.

[0148] In some embodiments, the addition of silver cyanide to an electrowinning cell 100 and / or barren solution return tank 5 may be performed as a function of electrowinning feed 37 composition. For instance, in cases where the electrowinning feed (e.g., PLS 37 or PLS 37 plus recycled barren solution 38) comprises gold and / or silver concentrations above 250 ppm, less or no silver cyanide may be added, since cathode 122 precious metal deposits are anticipated to be softer and / or more easily removed via an integrated wash system 108. However, in instances where gold and / or silver concentrations in the electrowinning feed solution 37, 38 are measured to be below 100 ppm, harder cathode deposits may be anticipated - thus, necessitating the addition of a temporary addition or boosting of silver cyanide to the electrowinning solution to soften deposits.

[0149] In some preferred embodiments, a composition of electrowinning feed solution (e.g., including Pregnant Leach Solution (PLS) 37 and / or barren solution 38) may be monitored over time and periodically measured. A threshold for gold and / or silver concentration may be predetermined or set. If the % gold and / or silver in the electrowinning feed solution is measured to be below (or falls below) the threshold, a harder deposit may be expected and one or more of the following steps may be taken: the current density in the electrowinning cell 100 may be increased (e.g., temporarily or semi-permanently), sodium cyanide 46 may be added to the electrowinning solution at some portion of the system 1 (e.g., introduced at inlet 26 of barren solution return tank 5) to increase sodium cyanide concentration of the electrowinning solution in the electrowinning cell 100, silver cyanide may be added to the electrowinning cell 100 or to barren solution return tank 5 (e.g., with caustic at inlet 25) to increase silver cyanide concentration of the electrowinning solution used in the electrowinning cell 100, an amount of additive may be added to the electrowinning solution at any portion of the system 1 (e.g., to a portion of barren return line 13 or via any inlet 24, 25, 26 to the barren solution return tank 5) to help soften deposits or encourage releasability of deposits, and / or a reverse polarity step may be performed by a rectifier (i.e., second portion of electrical system) 168 of the electrowinning cell 100 at any time during the electrowinning process, particularly in cases where there are occurrences of hard or difficult deposit formation on electrodes 121 , 122, without limitation.

[0150] Conversely, if the % gold and / or silver in the electrowinning feed solution 37 is measured to be above (or rises above) the threshold, a softer deposit may be expected and one or more of the following steps may be taken: decrease current density in the electrowinning cell 100; remove sodium cyanide 46 from, or decrease sodium cyanide 46 concentration of the electrowinning solution in the electrowinning cell 100; remove silver cyanide from, or decrease silver cyanide concentration of the electrowinning solution in the electrowinning cell 100; remove an amount of additive from, or decrease an amount of an additive added to the electrowinning solution used in the electrowinning cell 100; and / or omit, skip, or do not perform a reverse polarity step during electrowinning in skid 3. Removal of agents and / or reduction of concentration of agents within the system 1 may be performed through dilution (e.g., introduction of plant water 40 to barren solution return tank 5 or at a portion of barren return line 13), without limitation.

[0151] An electrowinning cell 100 may be provided. An electrowinning feed solution, which may comprise pregnant leach solution 36 with or without recycled barren solution 38) may be provided to the electrowinning cell 100 at an inlet 131 thereof. A concentration of precious metals in the electrowinning feed solution may be measured (e.g., ppm Au, ppm Ag). Sodium cyanide 46 may be added to the electrowinning feed solution directly in a first skid 2 of the system 1 , and / or indirectly (e.g., to a barren solution return tank 5 in a third skid 4 of the system 1 ) to boost the overall concentration of NaCN in the electrowinning solution flowing within the system 1 and / or used in the electrowinning cell 100. The boosted overall concentration of NaCN may, for example, comprise between 1 and 4 %weight of NaCN), in order to prevent the formation of hard cathode deposits in the electrowinning cell 100. Current density within the electrowinning cell 100 may be maintained above 40 A / m2of cathode area, but is preferably kept to less than 200 A / m2of cathode area for energy savings. If further softening of deposits becomes necessary, optional steps may be further employed. For example, silver cyanide solution may be added to the electrowinning feed solution upstream of an electrowinning cell inlet 131 , or to the electrowinning cell 100, or to a barren solution return tank 5. An additive as described above may be added to the electrowinning feed solution or to the electrowinning cell. One or more reverse polarity steps may be performed, e.g., by switching the polarity or charge of the anodes 121 and cathodes 122 in the electrowinning cell 100. Mechanical cleaning steps may be performed, e.g., by virtue of energizing an ultrasonic transducer, producing a high pressure spray, activating a mechanical cathode and / or anode scraper, and / or mechanically vibrating one or more cathodes and / or anodes, without limitation. It will be appreciated by those skilled in the art that the above steps may be performed in any useable order, and that any one of the above mechanical cleaning steps may be performed in with other recited steps, in any combination as needed to effect soft cathode deposits and / or clean electrodes 121 , 122.

[0152] For embodiments employing an optional cathode wash cell, similar steps may be performed. In such cases, some or all of the steps outlined above which could be used in conjunction with operation of an electrowinning cell 100 may be performed in conjunction with the cathode wash cell, without limitation. EXAMPLE 1

[0153] According to one non-limiting embodiment, an electrowinning process may involve providing an electrowinning cell with an electrowinning solution comprising a sodium cyanide concentration which is greater than or equal to 0.6 weight% to produce a soft deposit during electrowinning; and / or providing an electrowinning solution comprising a sodium cyanide concentration greater than or equal 1 .0 weight% to an electrowinning cell to soften a hard deposit already formed during electrowinning, without limitation.

[0154] Sodium cyanide may be added to the elution solution to strip the carbon as conventionally done. For example, an AARL circuit may utilize an approximately 5% NaCN pre-soak with 10 BV rinse, which equates to an approximately 0.32% NaCN concentration in the final electrowinning solution. As another example, the AARL circuit may utilize an approximately 5% NaCN pre-soak with 6 BV rinse, which equates to an approximately 0.52% NaCN concentration in the final electrowinning solution.

[0155] However, in order to produce softer deposits and / or discourage hard cathode deposit formation according to the invention, preferred embodiments employ the use of higher percent NaCN pre-soak concentrations and / or lesser BV of wash solution, in order to provide a final electrowinning solution having NaCN concentrations that are greater than or equal to 0.65 weight %. Most preferably, final NaCN concentrations are maintained above 1 %, for example, between 1 and 4% by weight. NaCN, without limitation.

[0156] For instance, in some preferred embodiments, a 2% by weight NaCN solution may be employed to soften and remove a hard anode and / or cathode deposit during electrowinning.

[0157] An additive may be present in the electrowinning solution, or added during electrowinning to soften cathode deposits and / or promote removal of cathode deposits. For example, a lead-containing reagent may be added to produce a >1 ppm Pb concentration in an electrowinning feed to produce a softer deposit during electrowinning. For example, 5 ppm Pb may be added to 500 ppm of Ag / Au / Cu in the electrowinning feed solution to obtain a soft cathode deposit.

[0158] The additive may be delivered to the electrowinning cell periodically, for example, it may be used / introduced to the electrowinning cell upon use of new or clean anodes / cathodes. In this regard, the additive may assist with preconditioning fresh cathode / anode surfaces. Preconditioning of the fresh, clean cathode / anode surfaces using the additive in the lixiviant may help with the formation of weak, soft, plated cathode layers, thus facilitating the removal of subsequent deposits formed thereover.

[0159] The additive may also be delivered continuously to the electrowinning cell and the amount of it added to the electrowinning cell optionally adjusted over time, for example, as a function of precious metal concentration in the electrowinning feed. In this regard, the small amount of lead present in solution may help soften newly-formed deposits of precious metals on wire cathodes / anodes.

[0160] In addition to, or in lieu of the aforementioned lead-based additive, lixiviant comprising various amounts / concentrations of a wetting agent, oxidant, and / or organic may be added to the electrowinning cell solution to produce a soft(er) deposit during electrowinning and / or to soften already-present hard deposits which were formed during the electrowinning process, without limitation.

[0161] Current density is normally limited to 5-15 A / m2for production cells, but according to some embodiments of the present invention, additional measures may be taken to soften deposits and / or loosen hard deposits by increasing the same. For example, in some embodiments, electrowinning may be performed at a current density which is greater than 40 A / m2of cathode area in order to achieve or encourage the formation of softer cathode deposits. In one particular test, an approximately 40 A / m2of cathode area current density condition was achieved using a 1 Amp setting on the rectifier. In order to economize process conditions, current density may be kept below 200 A / m2of cathode area.

[0162] EXAMPLE 2

[0163] An electrowinning cell 100 or an electrowinning system 1 according to embodiments may be configured for automated self-cleaning. It may include an integral electrode spray system and means for cathode sludge discharge which reduces the need for operations staff for cell service. The electrowinning cell 100 or electrowinning system 1 may comprise an enclosed and / or ventilated cabinet. The electrowinning cell 100 or electrowinning system 1 may be configured to reduce and / or eliminate operator exposure to process solution, fumes, or live electrical components.

[0164] The electrowinning cell 100 or electrowinning system 1 may comprise “direct connect” electrodes and / or may include electrode current monitoring / trending (e.g., HH “high-high” and LL “low-low” current alarms). With a direct connect electrode setup, the electrowinning cell 100 or electrowinning system 1 may be configured such that no bus bar maintenance is required, and / or conventional risks of electrode / bus bar overheating issues and / or potential cell fires is avoided.

[0165] In some embodiments, flexible flow rates up to 34.1 m3 / hr (or approximately 150 gallons per minute) may be achieved, vs. a traditional cell throughput of 14.8 m3 / hr (or approximately 65 gallons per minute), without limitation. Flow rates up to 80 m3 / hr (or approximately 350 gallons per minute) may be achieved in some embodiments. Due to its increased throughput, an electrowinning cell 100 or electrowinning system 1 according to embodiments may effectively replace two or more traditional sized electrowinning cells operating in parallel. Thus total floor space area (i.e., “footprint”) typically required for electrowinning cells may be reduced, and equipment may be consolidated.

[0166] An electrowinning cell 100 or electrowinning system 1 according to embodiments may be suitable for Zadra and AARL elution schemes as well as gravity gold circuits, without limitation. The electrowinning cell 100 or electrowinning system 1 may comprise an automated hard deposit removal function, e.g., an automated and / or flexible sequencing of electrodes and solution handling, without limitation.

[0167] In some cases, a site employing an electrowinning cell 100 or electrowinning system 1 according to embodiments might anticipate at least one or two cleaning cycles in a 2-week operation period; however, more or fewer cleaning cycles may be achieved in the same operation period, without limitation. Cleaning cycle frequency or periods of time between cleaning cycles may be varied and these can be adjusted to optimize electrowinning efficiency and / or extend electrode life for a particular site’s operations.

[0168] An electrowinning cell 100 or electrowinning system 1 according to embodiments may be configured for automated operation and process data trending through the use of a PLC / HMI. The electrowinning cell 100 or electrowinning system 1 may comprise ethernet communication to a plant DCS, without limitation. Various internet and / or communication protocols (wired or wireless) may be employed, without limitation.

[0169] Since embodiments can obviate the need for local personnel to remain onsite (e.g., to open / close the electrowinning cell and / or to remove, inspect, or clean cathodes manually, greater precious metal accountability can be achieved and security concerns over theft of valuable product can be mitigated.

[0170] As a non-limiting exemplary embodiment, the following utilities / interfaces may be employed, without limitation:

[0171] • (1) x Electrical Power Feed, Flexible (480V / 60Hz / 3phase or 575V / 60Hz / 3 phase or 380V / 50HZ / 3phase, 50 kW);

[0172] • Pregnant Solution Feed;

[0173] • Barren Solution Discharge;

[0174] • Ventilation Discharge to Atmosphere;

[0175] • Instrument Air (620 kPag 180 psig);

[0176] • Plant Air (620 kPag / 80 psig);

[0177] • Fresh Water;

[0178] • Reagents: NaOH & NaCN

[0179] It should be understood that there may be multiple electrical power feeds, without limitation.

[0180] It should further be understood that other types of electrical power feeds may be used, without limitation.

[0181] Turning now to the figures, certain apparatus may help facilitate practicing the above novel methods and / or process steps of electrowinning. The apparatus may comprise equipment having one or more novel technical features or a combination of one or more of the features shown in the figures and / or described below. It should be understood and appreciated to the reader of this description that certain numerically referenced technical features are shown and / or described in an effort to most clearly describe embodiments and / or depict a best mode(s) of practicing embodiments of the invention. However, it is possible that those skilled in the art may opt to practice embodiments which do not include each and every one of the numerically-referenced features. It is also envisaged that in light of this disclosure, those skilled in the art may opt to practice embodiments which use different combinations of only certain ones of the technical features depicted and / or shown.

[0182] An electrowinning system 1 may comprise a first skid 2, a second skid 3, and a third skid 4. The first skid 2 may comprise means for feeding a pregnant leach solution 37 or other electrowinning feed to an electrowinning cell 100 (e.g., provided to the second skid 3 of the system 1 ). The electrowinning system 1 may comprise a filter 11 , filtering means, or a filtering operation. The filter 11 , filtering means, or a filtering operation may comprise an inline canister filter configured for filtering barren solution 38, as depicted, without limitation. As depicted, some embodiments may provide the filter 11 , filtering means, or filtering operation to the first skid 2 of the system 1 .

[0183] The electrowinning system 1 may comprise a sludge pump 10, product pumping means, or a pumping operation for moving product (i.e. , sludge) from an electrowinning cell 100 in the system 1 . The sludge pump 10, product pumping means, or a pumping operation may comprise, for example, as shown, a pneumatically-driven pump configured to receive air or gas 42 via an air inlet 29 to drive the sludge pump 10, without limitation. As depicted, some embodiments may provide the sludge pump 10, product pumping means, or pumping operation to the first skid 2 of the system 1 . Of course, this pump could alternatively be provided to the second skid 3 of the system 1 adjacent to the electrowinning cell 100, on the electrowinning cell 100, or mounted to a skid or frame 14 thereof. It should also be understood that the electrowinning cell 100 could be oriented such that it is rotated 180 degrees from what is shown, about its vertical axis. In such an embodiment, the sludge pump 10, product pumping means, or pumping operation may be provided to the third skid 4 of the system 1 , without limitation.

[0184] A barren solution return tank 5 may be provided to the third skid 4 of the electrowinning system 1. The barren solution return tank 5 may contain barren solution 38 received from a client / customer process or operation. The barren solution return tank 5 may contain barren solution 38 received from the electrowinning cell 100, for example, barren solution 38 leaving an outlet 6 of the electrowinning cell 100. The barren solution return tank 5 may comprise a sloped floor 19 leading to a drain 21 and / or to a second outlet 63 of the barren solution return tank 5 which is configured to remove solids 44 and / or solids- heavy barren solution 38 from the barren solution tank 5. It should be understood that the sloped floor 19 of the barren solution return tank 5 may not be sloped in certain embodiments. A solids return 7 may connect the second outlet 63 to the first skid 2 and / or portions of the second skid 3 as depicted. For example, as depicted, the solids return 7 line may join a sludge / product discharge 130 at a second junction 166 to join with cathode sludge / product 43 leaving the electrowinning cell 100. As shown, the second junction 166 may be provided between piping extending from sludge / product discharge 130 of the electrowinning cell 100 and solids return 7, without limitation.

[0185] The third skid 4 may, in addition to the second outlet 63, comprise a first outlet 18 coming from barren solution return tank 5. This first outlet 18 may be provided slightly above the second outlet 63, such as adjacent to or above a top portion of sloped floor 19. The first outlet 18 may fluidly communicate with an electrowinning return pump 15. The electrowinning return pump 15 may be configured to move barren solution 38 from the barren solution return tank 5 to a valve 16 (such as a multi-way (e.g., 3-way) valve as shown, or optionally, one or more independent control valves or means for selectively directing flows between a plurality of return / recycle lines 17, 13). The valve 16 may be referenced herein as a “3-way valve”, without limitation and many alternative configurations are envisaged by the inventors. The valve(s) 16 may be configured to selectively divert flow between a “return to first skid piping 17, and / or one or more barren return lines or piping 13. A barren return line or pipe 13 may be configured as "return to client process piping from the barren solution return tank 5, for example, to another barren solution tank for adsorption or elution, without limitation. A barren return line or pipe 13 may be configured as a return line to the first skid 2, without limitation. For example, a barren return line or pipe 13 may, as shown, be configured to return barren solution 38 to an inlet 131 of the electrowinning cell 100 to fill tank 111. As another example, barren return line or pipe 13 may, as shown, be configured to return barren solution 38 to a filter 11 for filtering the barren solution 38 prior to delivery to an electrowinning cell 100 wash system 108 which will be described hereinafter.

[0186] The barren solution return tank 5 may be configured to receive plant water 40 by virtue of plant water delivery piping 12, without limitation. The plant water delivery piping 12 may extend between first 2 and third 3 skids of the system, and may be fed with plant water 40, for example via to a plant water inlet 30 provided to the first skid 2, without limitation. The plant water delivered to inlet 30 and / or carried within plant water delivery piping 12 may, without limitation, comprise process water, reclaimed water, freshwater, potable water, and / or recycled water, without limitation.

[0187] A level transmitter 28 may further be provided to the barren solution return tank 5 for relaying a current fluid level within the tank 5, without limitation.

[0188] Above the sloped floor 19, a substantially vertical baffle 20 may extend within the barren solution return tank 5. While a single baffle 20 is conceived and shown, a plurality baffles 20 may also be provided, without limitation. The baffle(s) 20 may comprise orientations and / or configurations other than what is depicted. A baffle 20 may be configured to disperse inflow of barren solution 38 leaving the electrowinning cell 100 via its outlet 6 and entering the barren solution return tank 5 via its barren solution inlet 58. A wash sprinkler 22 for washing internal surfaces of barren solution return tank 5 may be provided to the barren solution return tank 5. A wire sampler 23 (e.g., for grabbing composite or grab samples of barren solution 38 can be provided to barren solution return tank 5. In some embodiments, wire sampler 23 can include a bleed stream from "Return to client process" piping 13 and / or may comprise a beaker for manual taking to an ICP or spectrometer for analysis, without limitation. Plant water fill piping 24 may be provided to the system 1 for adjusting fluid levels or adjusting composition of fluids within barren solution return tank 5. The plant water fill piping 24 may enter the barren solution return tank 5 from an upper portion thereof, for example, through a pipe flange inlet. A sodium cyanide inlet 25 may be provided to the barren solution return tank 5 for adjusting / increasing NaCN concentration, and / or for receiving an amount of NaCN 46, without limitation. A caustic inlet 26 (for adjusting / reducing pH via NaOH addition may be provided to the barren solution return tank 5, without limitation. Caustic solution 45, other reagent(s), and / or other additive(s) may be delivered to barren solution return tank 5 via the caustic inlet 26, plant water fill piping 24, sodium cyanide inlet 25, or its own one or more separate inlets (not shown), without limitation. In the embodiment depicted, caustic solution 45 and / or other reagent(s) or additives described herein may be provided to caustic inlet 26. As discussed above, a reagent or additive may comprise silver cyanide, lead-containing reagent, surfactant, hard deposit inhibitor, or the like, without limitation.

[0189] A barren filtrate return / recycle line 27 may be provided to the electrowinning system 1 . For example, the barren filtrate return / recycle line 27 may be provided to the third skid 4. The barren filtrate return / recycle line 27 may extend from a filter press 47 configured for receiving and dewatering sludge / product 43 from discharge electrowinning cell discharge 130. The filter press 47 may be provided downstream of sludge / product outlet piping 34 (leaving sludge pump 10) and may be provided upstream of the barren solution return tank 5. The filter press 47 may comprise an inlet 61 which receives sludge / product 43 from the electrowinning system 1 .

[0190] Filtrate leaving the filter press 47 may enter barren filtrate return / recycle line 27 and be delivered at least in part to barren solution return tank 5. Dewatered cathode sludge 48 leaving the filter press 47 may enter a dewatered cathode sludge refinement process 49, for example, on a customer or client end, without limitation. A conveyor 56 may be used to transport the dewatered cathode sludge 48 to the dewatered cathode sludge refinement process 49. Some or all of the filtrate leaving the filter press 47 may return to the barren solution return tank 5 (e.g., via return / recycle line 27). Some or all of the filtrate leaving the filter press 47 may return to the customer via a “barren solution return to customer” 60. It should be understood that the filter press 47 shown and described is mentioned as a preferred best mode of filtration and it may be alternatively replaced with another type of filter or with equivalent means for vacuum or pressure filtration without limitation. Alternatively, filter press 47 may be replaced by any suitable conventional dewatering process or dewatering device, including a screw press, shaker table, centrifuge, spiral, or the like. Thus, where used herein, the term “filter press 47” may be replaced with the term “filter” or “dewatering process”, without limitation.

[0191] A decant 9 configured to remove electrowinning solution from tank 11 may be provided within the system 1 . The decant 9 may be configured to fluidly communicate with or join a flow of product / sludge 43 leaving electrowinning cell 100 and / or solids 44 leaving barren solution return tank 5. For example, decant 9 may, as shown, connect with piping leaving sludge / product discharge 130 at a first junction 165. The first junction 165 may be provided between decant 9 and piping of sludge / product discharge 130. The first junction 165 may be provided upstream of second junction 166 or otherwise join piping of the sludge / product discharge 130 before solids return 7 does.

[0192] A vent 8 may be provided to or extend from one or more pieces of equipment, such as to the electrowinning cell 100 (and / or barren solution return tank 5) to allow safe passage of gasses. The vent 8 may be configured as piping or ductwork configured to hold an off gas 41 , without limitation. Off gas 41 flow may be measured using a flow measuring device 187, for example, as the off gas 41 passes through the vent 8 or equivalent downstream ductwork as suggested in FIG. 27. In some embodiments, one or more than one flow measuring device 187 may be employed in the electrowinning system 1 , for example, a flow measuring device 187 may be provided at different portions or locations of the vent 8 as depicted, without limitation. The off gas 41 may be delivered to an emissions control 55 portion of a customer or client’s flowsheet by virtue of a blower or exhaust fan 52 powered by drive motor 50. The drive motor 50 may be electric, pneumatic, or hydraulic, and thus powered by electricity or pressurized fluids, without limitation.

[0193] Before passing to a vent stack 54, the off gas 41 may pass through a controllable damper 53 and / or a controllable blower or exhaust fan 52. A second damper (e.g., in the form of a butterfly valve) may be connected to line 41 leaving the barren solution return tank 5. Where used, an exhaust fan 52 may, in some embodiments be controlled by a Variable Frequency Drive (VFD), without limitation. A valve 31 (with optional regulator) may be provided to the system 1 , for example in the first skid 2. The valve 31 may be configured for controlling air or gas flow through air or gas inlet 29 and may comprise one or more control valves, without limitation.

[0194] A valve 32 (with optional regulator) may be provided to the system 1 , for example in the first skid 2. The valve 32 may be configured for controlling plant water flow through plant water inlet 30 and may comprise one or more control valves, without limitation.

[0195] The system may comprise a wire sampler 33 for taking composite or “grab” samples of Pregnant Leach Solution (PLS) 37 feeding the system 1 . The wire sampler 33 may include a bleed stream from PLS inlet piping 36. The wire sampler 33 may also comprise a beaker for manually taking PLS 37 samples to an ICP or spectrometer, without limitation.

[0196] The electrowinning system 1 may further comprise filter outlet piping 35 leaving the filter 11 , filtering means, or filtering operation. The filter outlet piping 35 may tie into one or more manifolds 115 of a wash system 108 provided to the electrowinning cell 100 in the second skid 3. Filter outlet piping 35 may be configured to deliver a washing fluid cleaning medium 39 to the wash system. The washing fluid cleaning medium 39 may comprise plant water 40, filtered barren solution 38, or a combination thereof, without limitation.

[0197] Pregnant Leach Solution (PLS) inlet piping 36 may also be provided to the electrowinning system 1 , for example, to the first skid 1 as shown. The (PLS) inlet piping 36 may be provided upstream of the second skid (e.g., form a portion of the first skid 2) and / or it may be configured to feed an inlet 131 to the electrowinning cell.

[0198] As can be gleaned from FIG. 27, a pump 51 may be used to send barren solution 38 back to the first skid 2 via a barren return 57. Barren solution sample line piping 59 may return barren solution to barren solution return tank 5. The barren solution sample line piping 59 may form a portion of the bleed stream used by wire sampler 23. One or more optional inline and / or in-tank heater(s) 62 may be employed by the system 1 for heating barren solution 38 within the system 1 , barren solution 38 returning to barren solution return tank 5, or barren solution 38 residing within the barren solution return tank 5. It is envisaged that additional heaters 62 may be applied to other piping 12, 13 within the system, without limitation.

[0199] Turning now to embodiments of an electrowinning cell 100, as depicted, an electrowinning cell 100 may be employed in the second skid 3 of the electrowinning system 1 . The electrowinning cell may comprise a tank 111. The tank 111 may be provided to the system in relationship to a frame 14. The frame 14 may comprise a skid (e.g., pallet structure or structure which may be moved, for example, with a forklift or other hoisting or transporting device), a base, one or more welded steel members, an external supporting structure(s) for supporting or mounting the electrowinn ing cell 100, an exoskeleton or one or more extension members surrounding or extending from electrowinning cell 100, members for mounting piping, a transmission 141 , lifting system 107, etc., without limitation. The frame 14 may be integral with the tank 111 , the tank 111 may support the frame 14 (or portions of the frame 14 such as piping support members), or the frame 14 may extend from one or more portions of the tank 111 . For purposes of this disclosure, where used herein, the term “frame” may comprise any structure which could be considered a housing, support structure, or anything that may be broadly construed as a frame (or portion) thereof given the plain meaning of the word “frame”. Embodiments of an electrowinning cell 100 or second skid 3 of an electrowinning system 1 may comprise any one or more of the following technical features in any desirable combination or configuration: a top cover 101 configured to protect a first electrical system portion 105; a housing 102 configured for protecting components of the electrical system portion 105; a safety latch 103 configured to keep the top cover 101 closed; a hinge 104 configured to pivotably support a front access cover 109 configured for accessing an electrode mounting system 106; a first electrical system portion 105 which may comprise an electrical distribution system, and / or which may include a distribution panel downstream of rectifier or rectifier distribution box, bus bars 174, terminal connections 125, 152, 153, or the like; an electrode mounting system 106 comprising an electrode support hanger 123 preferably made of a non-conductive, insulative material and being configured to support (e.g., by hanging) one or more electrodes 121 , 122; a lifting system 107 configured to lift an electrode mounting system 106 or upper chassis 112 or component 112a, 112b thereof; the lifting system 107 being configured to raise and lower electrodes 121 , 122 from the tank 111 of the electrowinning cell; a static or dynamic wash system 108 which is configured to wash one or more electrodes 121 , 122, such as one or cathodes 122 and / or one or more anodes 121 ; the wash system 108 being configured, in some embodiments, to wash the one or cathodes 122 and / or one or more anodes 121 while the one or cathodes 122 and / or one or more anodes 121 reside in the tank 111 ; the wash system 108 being configured, in some embodiments, to wash the one or cathodes 122 and / or one or more anodes 121 as they are being removed from and / or lifted from the tank 111 ; the wash system 108 being configured, in some embodiments, to wash the one or cathodes 122 and / or one or more anodes 121 when they are at least partially removed from and / or lifted out of the tank 111 in a deployed configuration of the electrowinning cell 100; a cover 109 configured for protecting the electrode mounting system 106 and electrical contact points between the electrodes 121 , 122 and the first electrical system portion 105; a handle 110 for opening and closing the cover 109 and / or for gaining manual access to the electrode mounting system from outside the electrowinning cell (e.g., for inspection or removal of electrodes 121 , 122 from the electrode support hanger 123; a movable upper chassis 112, which, if configured as a split upper chassis 112 may comprise a first part 112a of a split movable upper chassis 112 and a second part 112b of a split movable upper chassis 112, as depicted in FIGS. 28a-c., without limitation; or, which may support the electrode mounting system 106 and / or various components (e.g., electrode support hanger 123) thereof. one or more guides 113 (e.g., for maintaining proper linear vertical motion path of movable upper chassis 112 relative to frame 114 and / or tank 111 ); one or more actuator(s) 114 provided for the lifting system 107 and which may be configured to help raise and lower the upper chassis 112 and / or electrode mounting system 106; wherein an actuator 114 may comprise, without limitation, a piston / cylinder, a rack and pinion, a ball screw drive, a jack (e.g., scissor jack), an actuated linkage, a worm drive, an actuated telescoping arm, or equivalent means for raising / lowering movable upper chassis 112 and / or electrode mounting system 106 in relation to the frame 14 and / or tank 111); one or more manifolds 115 for providing a fluid washing cleaning medium 39 such as filtered barren solution 38 to wash system 108; the one or more manifolds 115, in some embodiments, the one or more manifolds being fluidly connected to a filter outlet piping 35 leaving a filter 11 and / or being fluidly connected to one or more feed pipes 116; one or more rigid or flexible feed pipes 116 provided to wash system 108 and communicating, in some embodiments, with one or more manifolds 115 and / or one or more inlets 117 to the tank 111; one or more spray bar inlets 117 of wash system 108 at entrance points to the tank 111; an optional gasket 118 provided between top cover 101 and housing 102 to prevent ingress of moisture or liquid and / or to protect components within first electrical system portion 105; one or more lift point connections 119 where the upper chassis 112 connects with one or more upper portions of the lifting system 107, such as where screw rods 144 are mounted to the upper chassis 112, without limitation; a branch / splitter 120 for a wash system 108, which is configured to extend between at least two manifolds 115, in some embodiments, the branch / splitter 120 connecting a first manifold 115 provided on a first side of the tank 111 to another manifold provided on a second side of the tank which is on an opposite side of the tank 111; at least one anode 121 (i.e., “electrode”) which may be positively charged during electrowinning or negatively charged in a reverse-polarity cycle; the at least one anode 121 being configured to be interspersed between adjacent cathodes 122; at least one cathode 122 (i.e., “electrode”) which may be negatively charged during electrowinning or positively charged in a reverse-polarity cycle; the at least one cathode 122 being configured to be interspersed between adjacent anodes 121 ; one or more electrode cable connection bar(s) 124; one or more terminals 125; a drive motor 126 for driving or powering lifting system 107; a feed weir 127 for controlling or setting a preferred fluid level within the tank 111; a feed box 128 configured for receiving electrowinning solution (e.g., PLS 37 and / or barren solution 38 via inlet 131 ; a sloped floor 129 configured for moving product / sludge 43 to outlet 130; an inlet 131 for receiving electrolyte or electrowinning solution such as PLS 37 and / or barren solution 38; wherein in some embodiments, the inlet 131 is configured to tie into pregnant leach solution (PLS) inlet piping 36 and / or "Return to first skid’ piping 17 containing barren solution 38, without limitation; a drip pan 132 provided under the first electrical system portion 105 and configured for catching and / or distributing condensation; the drip pan 132, in some embodiments, doubling as a hood for preventing off gas 41 from escaping through an upper portion of the electrowinning cell 100; a skirt, skirting, or skirting portion 133 configured to provide a moving seal 134 to prevent egress of off gas 41 and / or vapors containing electrolyte from escaping the tank 111 ; the skirt, skirting, or skirting portion 133 being, in some embodiments, further configured to direct off gas 41 to ports 170 when the lifting system 107 is engaged and the upper chassis 112 and / or electrode mounting system 106 is raised; a venting duct manifold 135 configured to direct off gas 41 to a vent 8; an outlet weir 136 configured for controlling fluid level within the tank 111 and or for providing egress of barren solution 38 from the tank 111 to outlet 6; an outlet launder 137 for moving barren solution 38 overflowing outlet weir 135 to outlet 6; one or more discharge cleaning nozzles 138 provided to move product / sludge 43 out of the tank 111 , in some embodiments, the one or more discharge cleaning nozzles 138 being provided adjacent to or just above a high point of sloped floor 29 and facing into the tank 111 and / or directed or oriented in such a way to promote removal of product / sludge 43 collecting at lower portions of tank 111 ; a return orifice 139 which is configured to provide fluid communication between the tank 111 and decant 9; an upper electrode extension portion 140 provided to one or more electrodes 121 , 122 for spanning a gap between a fluid level within tank 111 and the electrode support hanger 123; at least one transmission 141 for use within a lifting system 107; at least one drive axle 142 for use within a lifting system 107; at least one gearbox 143 (e.g., differential, drive splitter, reducer, joint) for reducing RPM, increasing mechanical advantage, and / or changing direction between two drive axles 142; the at least one gearbox 143 being configured for use within a lifting system 107; one or more screw rods 144 for use within a lifting system 107; one or more ball screw drives 145 for use within a lifting system 107; one or more drive coupling(s) 146 for use within a lifting system 107; one or more spray bars 147 of a wash system 108 one or more spray nozzles 148 provided to the one or more spray bars 147; one or more orifices in the one or more spray bars 147 which are configured to deliver fluid washing cleaning medium therethrough; a nozzle opening 150 provided to one or more spray nozzles 148 and which may be configured to deliver a spray pattern 151 for washing one or more electrodes 121 , 122; a first portion 152 of an electrical connector (e.g., a horizontal cable or a 1stcurrent transmitter portion); a second portion 153 of an electrical connector (e.g., a vertical cable connector or a 2ndcurrent transmitter portion); at least one receiving portion 154 provided to an electrode support hanger 123 for receiving and supporting an upper end of at least one electrode 121 , 122; wherein the receiving portion 154 may comprise an undercut slot, an undercut slit, a channel, a groove, a track, or a retention portion which is complementary to or configured to accept and retain an enlarged portion 155 of an electrode 121 , 122; an enlarged portion 155 on an upper portion of each electrode 121 , 122, such as a “T”, dovetail, flanged portion, extruded head, roundbar having a diameter which is larger than a thickness of its upper electrode extension portion 140; a cable mount 156, such as a quick connect electrical terminal; piping 157 to a discharge cleaning nozzle 138, which may tie into plant water delivery piping 12; one or more guide rods 158 (of guide(s) 113) which are configured to keep the upper chassis 112 in relative vertical alignment with respect to tank 111 when the lifting system 107 is deployed, the upper chassis 112 is raised / lowered, and / or when the electrowinning cell 100 is in an extended position with electrodes 121 , 122 raised (as shown in FIG. 18). one or more guide tubes 59 (of guide(s) 113) for protecting and guiding or serving as a bearing surface for one or more guide rods 158; a protective sheath 160 configured for protecting a screw rod 144 for embodiments where a screw drive is used as an actuator 114 of the lifting system 107. an insulative liner 161 for protecting inner surfaces of the tank 111 and / or preventing electrical arcing or electrical contact between electrodes 121 , 122 and inner tank 111 surfaces; one or more guiding features 162 such as one or more slits, one or more slots, one or more tracks, or the like, which are configured for vertically guiding one or more electrodes 121 , 122 as they are raised from and / or lowered into the tank 111 by virtue of the lifting system 107; wherein the one or more guiding features 162 are preferably made of an insulative material and / or integrally-formed with the insulative liner 161 , without limitation; a closed end, capped end, or endcap 163 provided to one or more of the spray bars 147; a decanting valve 164; a dispersion baffle 167; a second electrical system portion 168 (e.g., rectifier and / or rectifier distribution box for providing current to the first electrical system portion 105); wherein in some embodiments, the rectifier may be provided remote (e.g., in a room separate from) the depicted electrowinning system 1 ; one or more optional cables 169 extending between the first electrical system portion 105 and the second electrical system portion (wherein in the figures, one or more optional cables 169 between 168 and 105 are depicted as dotted lines in FIGS. 22 & 23, but cables 169 may not be shown in each figure for clarity or omitted from certain embodiments); one or more ports 170 which are configured to allow off gas 41 to pass from tank 111 to venting duct manifold 135 and eventually out of vent 8; one or more optional vertical cables 171 within electrical distribution system 105 and / or electrode mounting system 106 which are configured to deliver current to at least one electrode 121 , 122, e.g., via connector(s) 152, 153, 156; one or more optional horizontal cables 172 within electrical distribution system 105 configured to deliver current to at least one electrode 121 , 122, e.g., via connector(s) 152, 153, 156; a current transmitter 173; one or more optional bus bars 174 within electrical distribution system 105; one or more lifting lug(s) 175 which may be provided to facilitate assembly of the electrowinning cell 100, or installation, removal, replacement or repair of upper portions of the electrowinning cell 100. They may be configured to assist with complete removal of the upper chassis 112 along with other portions operably connected to the upper chassis 112, without limitation. The one or more lifting lug(s) 175 may be configured as a lift eye, hook, or the like and engageable with a cable, chain, or hoist for lifting the chassis 1 12 up and away from the tank 111 and / or away from portions of frame 14; wherein by hoisting the upper portion of electrowinning cell 100 high enough away from tank 1 11 and / or frame 14 via the lifting lugs 175, guide rods 158 (of guides 113) may be removed from their respective guide tubes 159 and the upper chassis 1 12 and its respective components (including elements 105, 106, 121 , 122, 133) can be removed or separated from other portions of the electrowinning cell 100;

[0200] - one or more unistruts 176, for example, provided as a portion(s) of upper chassis 112, and / or which may be used for supporting and / or for securing the electrode support hanger 123 to the upper chassis 112. The unistrut 176 may form a portion of electrode mounting system 106;

[0201] - an insulative electrode frame 177 (e.g., Integrated electrode electrical insulator surrounding or arranged proximate peripheral edges of electrodes 121 ,122);

[0202] - a lower insulative flow-restricting baffle 178 (e.g., an integrated electrode electrical insulator provided underneath electrodes 121 , 122 and above sloped floor 129, and / or attached to lower portion of insulative electrode frame 177; for example, which may be integral with or separable from frame 177, or which may be configured to restrict transverse flow across tank 111 and / or prevent short-circuiting of electrodes 121 , 122);

[0203] - one or more cables 184 (e.g., from rectifier 183 to electrodes 121 , 122 of electrowinning cell 100), which may be directly connected to each electrode 121 , 122;

[0204] - one or more openings 186 (e.g., through feed distributor 167); and / or

[0205] - a flow measuring device 187.

[0206] Embodiments of an electrowinning system 1 may comprise any one or more of the following technical features in any desirable combination or configuration:

[0207] - a damper 179 (e.g., for controlling delivery of off gas 41 from barren solution return tank 5);

[0208] - a control panel 180 (e.g., which may comprise an integrated and / or automated control panel);

[0209] - a GUI / HMI interface 181 (e.g., which may include a visual display output, screen output, indicia); - one or more individual electrode voltage or current signal readout(s) 182 (e.g., displayed via the GUI / HMI interface 181);

[0210] - one or more rectifier(s) 183;

[0211] - one or more cables 184 (e.g., from rectifier 183 to electrodes 121 , 122 of electrowinning cell 100);

[0212] - one or more cables 185 (e.g., from control panel 180 to rectifier(s) 183);

[0213] - one or more openings 186 (e.g., through feed distributor 167); and / or

[0214] - a flow measuring device 187.

[0215] In this specification, adjectives such as first and second, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or step, but rather could be one or more of that integer, component, or step etc.

[0216] The above description of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The invention is intended to embrace all alternatives, modifications, and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above-described invention.

[0217] In this specification, the terms ‘comprises’, ‘comprising’, ‘includes’, ‘including’, or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed. Moreover, it should be understood that while certain method steps and / or apparatus components or features may be shown or discussed together, it is anticipated by the inventors that one or more features and / or steps may be combined or grouped without employing other mentioned features and / or steps. Additionally, method steps may be performed in sequences other than what is expressly depicted or disclosed herein, such that the order of execution of the steps may be performed in various different orders. Moreover, it is anticipated that certain steps or featured elements described and / or shown herein may be optionally omitted, without limitation. Reference Numeral Identifiers

[0218] 1 Electrowinning system

[0219] 2 First skid (e.g., PLS feed, filter, sludge pumping)

[0220] 3 Second skid (e.g., electrowinning cell skid, electrowinning)

[0221] 4 Third skid (e.g., barren return tank skid, barren solution recycle / storage)

[0222] 5 Barren solution return tank (containing barren solution)

[0223] 6 Outlet (electrolyte)

[0224] 7 Solids return (from barren solution tank 5)

[0225] 8 Vent

[0226] 9 Decant (electrolyte)

[0227] 10 Sludge pump (e.g., pneumatic or electric pump, slurry pump)

[0228] 11 Filter (e.g., inline canister filter configured for filtering barren solution)

[0229] 12 Plant water delivery piping (from first skid 2)

[0230] 13 Barren return line or piping (e.g., "Return to client process" piping from barren solution return tank 5, for example, to another barren solution tank for adsorption or elution - or return to first skid 2, for example, to tank 111 or filter 11)

[0231] 14 Frame (e.g., skid, base, welded steel members, electrowinning cell 100 external supporting structure, exoskeleton or extension members of electrowinning cell 100)

[0232] 15 Electrowinning return pump

[0233] 16 Valve, multi-way valve, 3-way valve (or optional separate control valves or means for directing or controlling flow to one or more return lines 17, 13)

[0234] 17 "Return to client piping

[0235] 18 First outlet (from barren solution tank 5)

[0236] 19 Sloped floor

[0237] 20 Vertical baffle

[0238] 21 Drain

[0239] 22 Wash sprinkler (for washing internal surfaces of barren solution return tank 5)

[0240] 23 Wire sampler (e.g., for grabbing composite or grab samples of barren solution - can include bleed stream from "Return to client process" piping 13 and comprise a beaker for manual taking to an ICP or spectrometer)

[0241] 24 Plant water fill piping (for adjusting level)

[0242] 25 Sodium cyanide inlet (for adjusting / increasing NaCN concentration)

[0243] 26 Caustic inlet (for adjusting / reducing pH via NaOH addition) 27 Barren filtrate return / recycle (from filter press dewatering sludge / product from discharge 130)

[0244] 28 Level transmitter

[0245] 29 Air inlet (to drive pneumatic sludge pump 10)

[0246] 30 Plant water inlet (for receiving process water, reclaimed water, freshwater, potable water, or the like)

[0247] 31 Valve with regulator (e.g., control valve(s) for air inlet 29)

[0248] 32 Valve with regulator (e.g., control valve(s) for plant water inlet 30)

[0249] 33 Wire sampler (e.g., for grabbing composite or grab samples of pregnant leach solution (PLS) - can include bleed stream from PLS inlet piping 36 and comprise a beaker for manual taking to an ICP or spectrometer)

[0250] 34 Sludge / product outlet piping (from sludge pump 10)

[0251] 35 Filter outlet piping (from filter 11 , ties into manifold(s) 115 of wash system 108)

[0252] 36 Pregnant Leach Solution (PLS) inlet piping

[0253] 37 Pregnant Leach Solution (PLS), electrowinning feed (electrolyte)

[0254] 38 Barren solution (electrolyte)

[0255] 39 Washing fluid cleaning medium (e.g., Filtered barren solution 38, Plant water 40)

[0256] 40 Plant water (e.g., process water, reclaimed water, freshwater, potable water, recycled water)

[0257] 41 Off gas (from tank 111 of electrowinning cell 100, or barren solution return tank 5)

[0258] 42 Air or gas (for driving sludge pump 10, for embodiments where sludge pump 10 is pneumatically-driven)

[0259] 43 Cathode sludge / product

[0260] 44 Solids, solids-heavy barren solution 38 (from barren solution tank 5).

[0261] 45 Caustic solution and / or other reagent(s) or additives (e.g., one or more additive(s), silver cyanide, lead-containing reagent, surfactant, hard deposit inhibitor, etc.)

[0262] 46 Sodium Cyanide

[0263] 47 Filter press

[0264] 48 Dewatered cathode sludge

[0265] 49 Dewatered cathode sludge refinement process (customer)

[0266] 50 Drive motor (electric, pneumatic, or hydraulic)

[0267] 51 Pump

[0268] 52 Blower / Fan (e.g., exhaust fan) 53 Damper

[0269] 54 Vent stack

[0270] 55 Emissions control

[0271] 56 Conveyor

[0272] 57 Barren return

[0273] 58 Barren solution inlet (to barren solution return tank 5)

[0274] 59 Barren solution sample line piping

[0275] 60 Barren solution return to customer

[0276] 61 Inlet (of filter 47)

[0277] 62 Optional inline and / or in-tank heater(s) (for barren solution 38, return tank 5)

[0278] 63 Second outlet (Barren solution return tank 5)

[0279] 100 Electrowinning cell

[0280] 101 Top cover

[0281] 102 Housing (for electrical system portion / electrical distribution system 105)

[0282] 103 Safety latch

[0283] 104 Hinge

[0284] 105 Electrical distribution system (e.g., distribution panel, downstream of a rectifier and / or power junction box 168, etc.)

[0285] 106 Electrode mounting system

[0286] 107 Lifting system

[0287] 108 Wash system

[0288] 109 Cover (Electrode mounting system)

[0289] 110 Handle

[0290] 111 Tank (electrowinning, e.g., stationary)

[0291] 112 Movable upper chassis

[0292] 112a First part (split movable upper chassis 112)

[0293] 112b Second part (split movable upper chassis 112)

[0294] 113 Guide(s) (for maintaining motion path of movable upper chassis 112 relative to frame 114 and stationary tank 111 )

[0295] 114 Actuator(s) (of lifting system 107)

[0296] (e.g., piston / cylinder, rack and pinion, ball screw drive, jack (e.g., scissor jack), actuated linkage, worm drive, actuated telescoping arm, or equivalent means for raising / lowering movable upper chassis 112)

[0297] 115 Manifold(s) (of wash system 108)

[0298] 116 Feed pipe(s) (of wash system 108) 117 Spray bar inlet(s) (of wash system 108)

[0299] 118 Optional gasket (between top cover 101 and housing 102)

[0300] 119 Lift point connection

[0301] 120 Branch / splitter (of wash system 108, extending between manifolds 115)

[0302] 121 Anode (electrode)

[0303] 122 Cathode (electrode)

[0304] 123 Electrode support hanger (non-conductive, insulative)

[0305] 124 Electrode cable connection bar(s)

[0306] 125 Terminal

[0307] 126 Optional drive motor (for lifting system 107; e.g., electric or hydraulic)

[0308] 127 Feed weir (for inlet 131)

[0309] 128 Feed box (for inlet 131 )

[0310] 129 Sloped floor (e.g., a deep angled trough or floor that changes in elevation or grade in one or more XYZ planes)

[0311] 130 Sludge / product discharge

[0312] 131 Inlet (electrolyte) - ties into Pregnant Leach Solution (PLS) inlet piping 36 and / or "Return to first skid” piping 17 containing barren solution

[0313] 132 Drip pan

[0314] 133 Skirt, skirting, or skirting portion

[0315] 134 Moving seal

[0316] 135 Venting duct manifold

[0317] 136 Outlet weir (for outlet 6)

[0318] 137 Outlet launder (for outlet 6)

[0319] 138 Discharge cleaning nozzle

[0320] 139 Return orifice

[0321] 140 Upper electrode extension portion(s)

[0322] 141 Transmission

[0323] 142 Drive axle

[0324] 143 Gearbox (e.g., differential, drive splitter, reducer, joint)

[0325] 144 Screw rod

[0326] 145 Ball screw drive

[0327] 146 Drive coupling(s)

[0328] 147 Spray bar(s) (of wash system 108)

[0329] 148 Spray nozzle(s) (of spray bar(s) 147) 149 Orifice(s) (spray bar(s) 147)

[0330] 150 Nozzle opening (of spray nozzle(s) 148)

[0331] 151 Spray pattern (typical - of spray nozzle(s) 148)

[0332] 152 First portion of electrical connector (e.g., horizontal cable, 1stcurrent transmitter portion)

[0333] 153 Second portion of electrical connector (e.g., vertical cable connector, 2ndcurrent transmitter portion)

[0334] 154 Receiving portion(s) (of electrode support hanger 123, e.g., undercut slot / slit, channel, groove, retention portion to accept enlarged portion(s) 155)

[0335] 155 Enlarged portion(s) (of electrodes 121 , 122, e.g., “T”, dovetail, flanged portion, extruded head, roundbar with diameter larger than thickness of upper electrode extension portion(s), or the like)

[0336] 156 Cable mount (e.g., quick connect terminal)

[0337] 157 Piping (to discharge cleaning nozzle 138, ties into plant water delivery piping 12)

[0338] 158 Guide rod (of guide(s) 113)

[0339] 159 Guide tube (of guide(s) 113)

[0340] 160 Protective sheath (for screw rod 144)

[0341] 161 Insulative liner

[0342] 162 Guiding feature(s) (e.g., insulative - slits, slots, track, for vertically guiding electrodes 121 , 122)

[0343] 163 Closed end, capped end, or endcap (of spray bar(s) 147)

[0344] 164 Decanting valve

[0345] 165 First junction (between Decant 9 and piping of Sludge / product discharge 130)

[0346] 166 Second junction (between piping of Sludge / product discharge 130 and solids return 7)

[0347] 167 Feed distributor, dispersion baffle, or flow-dispersing baffle (e.g., may be provided in a plurality - with one at an entrance side and one at an exit side of the tank 111 of the electrowinning cell 100. May comprise a plate with openings therethrough)

[0348] 168 Power junction box (optional) (e.g., communicating with a rectifier (not shown) and electrical distribution system 105)

[0349] 169 Cables - ((optional) cables 169 extending between elements 168 and 105 may not be shown for clarity)

[0350] 170 Ports (venting duct manifold 135)

[0351] 171 Vertical cable to electrodes 121, 122; (optional)

[0352] 172 Horizontal cable to electrodes 121 , 122 (optional) 173 Current transmitter

[0353] 174 Bus bar (optional)

[0354] 175 Lifting lug(s) (e.g., for complete removal of upper chassis 112 (including elements 105, 106, 121 , 122, 133)

[0355] 176 Unistrut (of upper chassis 112 for securing electrode support hanger 123 to the upper chassis 112)

[0356] 177 Insulative electrode frame (e.g., Integrated electrode electrical insulator surrounding or arranged proximate peripheral edges of electrodes 121 ,122)

[0357] 178 Lower insulative flow-restricting baffle (e.g., Integrated electrode electrical insulator provided underneath electrodes 121 , 122 and above sloped floor 129, and / or attached to lower portion of insulative electrode frame 177 - May be integral with or separable from frame 177, configured to restrict transverse flow across tank 111 and / or prevent short-circuiting of electrodes 121 , 122)

[0358] 179 Damper (for controlling delivery of off gas 41 from barren solution return tank 5)

[0359] 180 Control Panel (e.g., integrated and / or automated control panel)

[0360] 181 GUI / HMI interface (e.g., visual display output, screen output)

[0361] 182 Individual electrode voltage or current signal readout(s)

[0362] 183 Rectifier(s) (may be a plurality in some embodiments)

[0363] 184 Cables (from rectifier 183 to electrodes 121 , 122 of electrowinning cell 100)

[0364] 185 Cables (from control panel 180 to rectifier(s) 183)

[0365] 186 Openings (through feed distributor 167)

[0366] 187 Flow measuring device

Claims

CLAIMSWhat is claimed is:

1. An electrowinning cell (100) comprising: a frame (14); a tank (111) supported by, coupled to, forming a portion of, surrounded by, and / or at least partially integrated with the frame (14); an upper chassis (112) comprising an electrode mounting system (106) configured to hold at least one electrode (121 , 122); and a lifting system (107) configured to raise and lower the upper chassis (112) in relation to the frame (14) and / or tank (111) to at least temporarily remove portions of the at least one electrode (121 , 122) from submersion within the tank (111).

2. The electrowinning cell (100) according to claim 1 , wherein the electrowinning cell (100) further comprises a wash system (108).

3. The electrowinning cell (100) according to claim 2, wherein the wash system (108) is provided to the tank (111 ).

4. The electrowinning cell (100) according to claim 2 or 3, wherein the wash system (108) comprises at least one manifold (115).

5. The electrowinning cell (100) according to claim 4, wherein the wash system (108) comprises two manifolds (115), each being provided on opposite sides of the tank (111).

6. The electrowinning cell (100) according to claim 5, wherein the two manifolds (115) are in fluid communication with each other via a branch / splitter (120) extending between and fluidly connecting the two manifolds (115) together.

7. The electrowinning cell (100) according to any one of claims 2-6, wherein the wash system (108) comprises one or more spray bars (147) spanning into and / or substantially across one or more portions the tank (111 ).

8. The electrowinning cell (100) according to any one of claims 2-7, wherein the wash system (108) comprises one or more feed pipes (116).

9. The electrowinning cell (100) according to any one of claims 2-8, wherein the wash system (108) comprises one or more spray bar inlets (117).

10. The electrowinning cell (100) according to any one of claims 2-9, wherein the wash system (108) is configured to receive a washing fluid cleaning medium within one or more manifolds (115), distribute the received washing fluid cleaning medium to one or more spray bars (147) spanning into and / or substantially across one or more portions of the tank (111 ), and emit the washing fluid cleaning medium through one or more orifices (149) in the one or more spray bars (147).11 . The electrowinning cell (100) according to claim 10, wherein each of the one or more spray bars (147) comprises a closed end, capped end, or endcap (163).

12. The electrowinning cell (100) according to claim 10 or 11 , wherein a plurality of spray bars (147) are employed, with each of the plurality of spray bars (147) being fed by the same manifold (115).

13. The electrowinning cell (100) according to any one of claims 10-12, wherein a plurality of spray bars are employed (147), wherein adjacent spray bars (147) are fed by different manifolds (115).

14. The electrowinning cell (100) according to claims 13, wherein each spray bar (147) is provided in an alternating arrangement, wherein a closed end, capped end, or endcap (163) of a first spray bar (147) is located on a first side of the tank (111 ) and wherein closed ends, capped ends, or endcaps (163) of second and third spray bars (147) provided immediately adjacent to and sandwiching the first spray bar (147) are located on a second side of the tank (111 ) which is opposite to and / or situated across from the first side of the tank (111).

15. The electrowinning cell (100) according to any one of claims 2-14, wherein the wash system (108) is configured to receive and deliver filtered barren solution as a washing fluid cleaning medium to clean the at least one electrode (121, 122); and / or wherein the wash system (108) is configured to receive and deliver plant water (e.g., process water, reclaimed water, freshwater, potable water, recycled water, without limitation) as a washing fluid cleaning medium to clean at least one electrode (121 , 122).

16. The electrowinning cell (100) according to any one of claims 2-15, wherein the wash system (108) is supported by the tank (111) and / or frame (14); and / or wherein the wash system (108) remains stationary with respect to the tank (111 ) and / or frame (14).

17. The electrowinning cell (100) according to any one of the preceding claims, wherein the lifting system (107) comprises one or more actuators (114).

18. The electrowinning cell (100) according to claim 17, wherein the one or more actuators (114) comprises a plurality of actuators (114).

19. The electrowinning cell (100) according to claim 17 or 18, wherein the one or more actuators (114) comprises a ball screw drive comprising a screw rod (144) protected by a protective sheath or shroud (160).

20. The electrowinning cell (100) according to any one of the preceding claims, wherein the lifting system (107) comprises one or more guides (113).21 . The electrowinning cell (100) according to claim 20, wherein the one or more guides (113) comprises a plurality of guides (113).

22. The electrowinning cell (100) according to claim 20 or 21 , wherein the one or more guides (113) comprises a guide rod (158) which is movable within a guide tube (159).

23. The electrowinning cell (100) according to claim 22, wherein the guide rod (158) is connected to the upper chassis (112), and wherein the guide tube (159) is connected to the tank (111 ) and / or the frame (14).

24. The electrowinning cell (100) according to any one of the preceding claims, wherein the electrode mounting system (106) comprises an insulative, non- conductive electrode support hanger (123) configured to hold at least one electrode (121 , 122); the electrode support hanger (123) comprising at least one receiving portion (154) configured to receive and retain at least one enlarged portion (154) of said at least one electrode (121 , 122).

25. The electrowinning cell (100) according to any one of the preceding claims, wherein the wash system (108) is configured such that as the lifting system (107) raises and lowers the upper chassis (112) in relation to the frame (14) and / or tank (111) to at least temporarily remove portions of the at least one electrode (121 , 122) from submersion within the tank (111 ), the at least one electrode (121 , 122) passes by one or more spray nozzles (148) configured to provide a spray pattern (151) of washing fluid cleaning medium to clean the at least one electrode (121 , 122) as it is being raised from submersion within the tank (111 ) via the lifting system (107).

26. The electrowinning cell (100) according to any one of the preceding claims, wherein the wash system (108) comprises one or more spray nozzles (148) within the tank (111) which are located above a weir (127, 136) and / or an operating fluid level line within the tank (111 ).

27. The electrowinning cell (100) according to claim 26, wherein the one or spray nozzles (148) are provided to one or more spray bars (147) spanning substantially across a width of the tank (111 ), e.g., from a first side of the tank (111 ) to a second side of the tank (111 ), or vice-versa.

28. The electrowinning cell (100) according to any one of the preceding claims, wherein the wash system (108) comprises one or more spray bars (147) within the tank (111 ) which are located above a weir (127, 136) and / or an operating fluid level line within the tank (111 ).

29. An electrowinning cell (100) comprising: a frame (14); a tank (111 ) supported by, coupled to, forming a portion of, surrounded by, and / or at least partially integrated with the frame (14); and, a wash system (108) configured to clean at least one electrode (121 , 122) within the tank (111 ).

30. The electrowinning cell (100) according to claim 29, wherein the wash system (108) is configured to receive and deliver filtered barren solution as a washing fluid cleaning medium to clean the at least one electrode (121 , 122); and / or wherein the wash system (108) is configured to receive and deliver plant water (e.g., process water, reclaimed water, freshwater, potable water, recycled water, without limitation) as a washing fluid cleaning medium to clean at least one electrode (121 , 122).31 . The electrowinning cell (100) according to claim 29 or 30, wherein the electrowinning cell (100) further comprises: an upper chassis (112) comprising an electrode mounting system (106) configured to hold at least one electrode (121 , 122); and a lifting system (107) configured to raise and lower the upper chassis (112) in relation to the frame (14) and / or tank (111 ) to at least temporarily remove portions of the at least one electrode (121 , 122) from submersion within the tank (111 ).

32. The electrowinning cell (100) according to any one of claims 29-31 , wherein the wash system (108) comprises one or more spray bars (147) each comprising one or more spray nozzles (148).

33. The electrowinning cell (100) according to claim 32, wherein the wash system (108) is provided to the tank (111 ).

34. The electrowinning cell (100) according to claim 32 or 33, wherein the wash system (108) comprises at least one manifold (115), at least one feed pipe (116), and / or at least one spray bar inlet (117) for supplying the one or more spray bars (147) with a washing fluid cleaning medium comprising filtered barren solutionand / or plant water (e.g., process water, reclaimed water, freshwater, potable water, recycled water, without limitation).

35. An electrowinning cell (100) comprising an upper chassis (112) having an electrode support hanger (123) attached thereto, the electrode support hanger (123) being configured to support and / or hold one or more electrodes (121 , 122) in at least a vertical direction, the electrode support hanger (123) comprising at least one receiving portion (154) configured to receive a respective at least one enlarged portion (155) provided to an upper portion of an electrode (121 , 122) and configured to support the electrode (121 , 122) from above, such that the electrode (121 , 122) hangs from the electrode support hanger (123).

36. The electrowinning cell (100) according to claim 35, wherein the at least one receiving portion (154) is configured to extend substantially horizontally across the electrode support hanger (123) and have a lower opening for providing clearance for an upper electrode extension portion (140), such that it is configured to receive said respective at least one enlarged portion (155) transversely, substantially horizontally, in a side-to-side or lateral sliding motion between the respective at least one enlarged portion (155) of the electrode (121 , 122), relative to the electrode support hanger (123).

37. The electrowinning cell (100) according to claim 35, further comprising a wash system (108).

38. An electrowinning cell (100) according to claim 37, further comprising at least one inlet (117) provided to the wash system (108) and communicating with a tank (111 ), the at least one inlet (117) being provided with a grommet and being sized with a minimum inner diameter which is greater than a maximum outer diameter of a spray bar (147) that is provided with or without nozzles (148), such that the spray bar (147) can be removed laterally through a sidewall of the tank (111 ) and through the at least one inlet (117) without interference or binding between the spray bar (147) and the at least one inlet (117) or sidewall of the tank (111 ).

39. The electrowinning cell (100) according to any one of claims 35-38, further comprising a lifting system (107) for raising and lowering the upper chassis (112) in relation to a tank (111 ) and / or frame (14).

40. An electrowinning cell (100) according to any one of the preceding claims, further comprising a current and / or voltage measuring device (187).41 . The electrowinning cell (100) according to claim 40, wherein the current and / or voltage measuring device (187) is configured to output a separate signal or readout for each electrode (121 , 122) in the electrowinning cell (100).

42. The electrowinning cell (100) according to claim 40, wherein the current and / or voltage measuring device (187) is configured to output a separate signal or readout for each cathode (122) in the electrowinning cell (100).

43. The electrowinning cell (100) according to claim 40, wherein the current and / or voltage measuring device (187) is configured to output a separate signal or readout for each anode (121) in the electrowinning cell (100).

44. The electrowinning cell (100) according to any one of claims 41 -43, wherein the current and / or voltage measuring device (187) is connected to an integrated and / or automated control panel (180).

45. The electrowinning cell (100) according to claim 44, wherein the automated control panel (180) is configured to directly or indirectly control the current and or / voltage delivered to one or more electrodes, cathodes (122), and / or anodes (121 ).

46. The electrowinning cell (100) according to claim 44 or 45, wherein the automated control panel (180) is configured to directly or indirectly receive and / or process each signal or readout.

47. The electrowinning cell (100) according to any one of claims 44-46, wherein the automated control panel (180) comprises a graphical user interface which is configured to display each separate signal or readout associated with each electrode, anode (121 ), or cathode (122) in the electrowinning cell (100).

48. The electrowinning cell (100) according to any one of the preceding claims, wherein one or more of the electrodes (121 , 122) are configured to slide-in and slide-out of an electrode support hanger (123) in a substantially lateral, sideways, horizontal, or transverse direction with respect to the electrode support hanger (123) of the electrowinning cell (100).

49. The electrowinning cell (100) according to claim 48, wherein the one or more electrodes (121 , 122) each comprise an upper enlarged portion (155) which is configured (e.g., shaped and / or sized) to slide into and remain within respective receiving portions (154) of the electrode support hanger (123).

50. The electrowinning cell (100) according to claim 49, wherein the upper enlarged portion (155) enables the one or more electrodes (121 , 122) to hang from the electrode support hanger (123) while supporting their own weight and the weight of electrowinning product accumulating or loading thereon.51 . An electrowinning cell (100) according to any one of the preceding claims, further comprising a feed distributor (167) located in the feed end and / or the discharge end of the electrowinning cell (100).

52. The electrowinning cell (100) according to claim 51 , wherein the feed distributor (167) is provided as a substantially planar dispersion baffle or flowdispersing baffle which comprises a number of openings which are sized, shaped, distributed, and / or configured to disperse fluids uniformly across a cross-section of the tank (111 ) of the electrowinning cell (100).

53. The electrowinning cell (100) according to claim 51 or 52, wherein the feed distributor (167) is removable and / or replaceable with another similar feed distributor (167) or a feed distributor (167) of a different configuration of openings.

54. The electrowinning cell (100) according to any one of claims 51 -53, wherein the number of openings in the feed distributor (167) is configured for a flow rate or flux of electrolyte feed through the tank (111) of the electrowinning cell (100).

55. An electrowinning cell (100) according to any one of the preceding claims, further comprising one or more integrated electrode electrical insulators (177, 178).

56. The electrowinning cell (100) according to claim 55, wherein the one or more integrated electrode electrical insulators (177, 178) comprises one or more flowrestricting baffles (178) which are each configured to protrude downwardly into a sludge collection trough above a sloped floor (129) within the tank (111 ) of the electrowinning cell (100).

57. The electrowinning cell (100) according to claim 56, wherein the one or more flow-restricting baffles (178) are triangular, chevron- shaped, or have edges which are spaced from and / or substantially parallel to the sloped floor (129).

58. The electrowinning cell (100) according to any one of claims 55-57, wherein the integrated electrode electrical insulators (177, 178) comprises one or more frame members (177) formed of an insulated material which are configured to surround or be arranged proximate peripheral edge portions of one or more electrodes (121 , 122) within the tank (111 ) of the electrowinning cell (100).

59. The electrowinning cell (100) according to claim 58, wherein the integrated frame members (177) and baffles (178) are integral with one another.

60. The electrowinning cell (100) according to claim 58, wherein the integrated frame members (177) and baffles (178) are separable from one another.61 . An electrowinning cell (100) according to any one of the preceding claims, further comprising an integrated discharge cleaning nozzle (138) which is configured to receive and deliver a fluid flow to a portion of the tank (111 ) of the electrowinning cell (100), and configured to move sludge (43) or other solids down a sloped floor (129) within the tank (111 ).

62. An electrowinning cell (100) comprising a plurality of independent lifting systems (107) and / or a plurality of independent wash systems (108).

63. An electrowinning system (1 ) comprising: an electrowinning cell (100) according to any one of claims 1 -34, preferably provided to a second skid (3) between a first skid (2) and a third skid (4), wherein the electrowinning system (1 ) is configured for receiving pregnant leach solution (37) from an upstream process, and delivering the same to an electrowinning cell (100); and wherein the electrowinning system (1 ) comprises a filter (11 ) configured for filtering barren solution (38) received from the electrowinning cell (100) or an electrowinning return tank (5).

64. The electrowinning system (1 ) according to claim 63, configured to deliver filtered barren solution and / or plant water (such as process water, reclaimed water, freshwater, potable water, recycled water) to a portion of the electrowinning cell (100) or to the second skid (3).

65. The electrowinning system (1 ) according to claim 64, further configured to deliver the filtered barren solution to a portion of a wash system (108) of the electrowinning cell (100) within the second skid (3).

66. The electrowinning system (1 ) according to any one of claims 63-65, wherein the third skid (4) comprises a barren solution tank (5) preferably having a sloped floor leading to a solids return (7) which connects to a sludge / product discharge (130) at a second junction (166).

67. The electrowinning system (1 ) according to claim 66, wherein the sludge / product discharge (130) is configured to communicate with a decant (9) extending from a tank (111 ) of the electrowinning cell (100) at a first junction (165).

68. The electrowinning system (1 ) according to any one of claims 63-67, wherein the third skid (4) comprises a barren solution tank (5) having an outlet (18) communicating with a three-way valve (16) configured to divert barren solution leaving the barren solution tank (5) to one of:-a client return;-a tank (111 ) of the electrowinning cell (100), for example, via piping supplied to the first skid (2);-a filter (11 ) preferably provided to the first skid (2) and then subsequently from the filter (11 ) to a wash system (108) of the electrowinning cell (100) preferably provided to the second skid (3).

69. The electrowinning system (1 ) according to any one of claims 63-68, further comprising any one or more of the referenced and numbered technical features described and / or shown, in any combination.

70. An electrowinning system (1) comprising: the electrowinning cell (100) according to any one of claims 1-62, and an integrated and / or automated control panel (180) which is directly or indirectly connected to:- the electrowinning cell (100);- a cell rectifier (183) communicating with the electrowinning cell (100); and / or- a cell rectifier (183) connected to the electrowinning cell (100).71 . The electrowinning system (1 ) according to claim 70, wherein the integrated and / or automated control panel (180) is configured to provide a plurality of separate inputs and / or receive a plurality of separate signal outputs from a respective number of electrodes (121 , 122) in the electrowinning cell (100), via the cell rectifier (183).

72. An electrowinning system (1) comprising: the electrowinning cell (100) according to any one of claims 1 -62, and an integrated process blower or exhaust fan (52) configured to expel exhaust from the electrowinning cell (100) via a vent (8).

73. The electrowinning system (1 ) according to claim 72, wherein the electrowinning system (1 ) further comprises an exhaust damper (53), the exhaust damper (53) fluidly communicating with the vent (8).

74. The electrowinning system (1 ) according to claim 73, wherein the blower or exhaust fan (52) and / or damper (53) has at least two operating set points which are controllable, for example, by an integrated and / or automated control panel (180) in the electrowinning system (1).

75. The electrowinning system (1 ) according to any one of claims 72-74, wherein the blower or exhaust fan (52) comprises a flow measuring device (187) and / or is configured to be directly or indirectly controlled using signal outputs from a flow measuring device (187) in the electrowinning system (1 ).

76. The electrowinning system (1 ) according to any one of claims 72-75, wherein the blower or exhaust fan (52) is controllable by a Variable Frequency Drive (VFD) to modulate extraction of off gas (41).

77. An electrowinning system (1) comprising: the electrowinning cell (100) according to any one of claims 1 -62, and a sludge removal system configured to remove sludge from the electrowinn ing tank (111) of the electrowinning cell (100) and / or from the barren solution return tank (5), the sludge removal system comprising at least one discharge cleaning nozzle (138) and / or at least one spray nozzle (148).

78. The electrowinning system (1 ) according to claim 77, wherein the electrowinning cell (100) comprises at least one spray nozzle (148) and a discharge cleaning nozzle (138).

79. The electrowinning system (1 ) according to claim 77 or 78, wherein the barren solution return tank (5) comprises at least one discharge cleaning nozzle (138).

80. A method of electrowinning comprising: providing an electrowinning cell (100) or system (1 ) according to any one of claims 1-62, and i.) mechanically raising the upper chassis (112) and electrode mounting system(106) to at least partially remove at least one electrode (121 , 122) from submersion within the tank (111 ) using a lifting system (107) between the frame (14) and upper chassis (112), or, ii.) washing the at least one electrode (121 , 122) using a wash system (108) provided to the electrowinning cell (100).81 . The method of electrowinning according to claim 42, wherein both steps i.) and ii.) are performed.

82. The method according to claim 81 , wherein steps i.) and ii.) are performed simultaneously.

83. The method of electrowinning according to any one of claims 80-82, wherein the step of washing the at least one electrode using a washing system (108) comprises running filtered barren solution through one or more orifices (149) fluidly communicating with a manifold (115) being supplied with said filtered barren solution.

84. The method of electrowinning according to any one of claims 80-83, wherein the step of washing the at least one electrode using a washing system (108) comprises spraying the at least one electrode (121 , 122) within an upper portion of the tank (111 ) at a location that is above an operating fluid level line within the tank (111) and / or above a weir (127, 136) of the electrowinning cell (100).

85. The electrowinning cell (100), system (1 ), or method of electrowinning according to any one of claims 2-84, wherein the wash system (108) remains substantially static in relation to the tank (111) and / or frame (14), for example, as depicted in the embodiments shown in FIGS. 1 -27.

86. The electrowinning cell (100), system (1 ), or method of electrowinning according to any one of claims 2-84, wherein at least a portion of the wash system (108) is dynamic and / or moves in relation to the tank (111) and / or frame (14), for example, as depicted in the embodiments shown in FIGS. 28a-c.

87. A control panel (180) for integrating with and automating an electrowinning system (1 ) comprising an electrowinning cell (100) and a cell rectifier (183) for modulating current and / or voltage to the electrowinning cell (100), the control panel (180) comprising: a graphical user interface comprising a display; and visual readout indicia on the display; wherein the visual readout indicia includes a plurality of separate current or voltage measurement readings, each of the measurement readings representing a separate current or voltage signal received from a respective number of electrodes (121 , 122) in the electrowinning cell (100), the separate current or voltage signal being received from the cell rectifier (183).

88. The control panel (180) according to claim 87, wherein the control panel (180) is configured to control standard polarity and reverse polarity current cycles fed to the electrodes (121 , 122).

89. The control panel (180) according to claim 87 or 88, wherein the control panel (180) is configured to be directly or indirectly connected to:- the electrowinning cell (100);- a cell rectifier (183) communicating with the electrowinning cell (100); and / or- a cell rectifier (183) connected to the electrowinning cell (100).

90. An integrated process blower or exhaust fan (52) which is configured to expel exhaust from an electrowinning cell (100) of an electrowinning system (1 ), the integrated process blower or exhaust fan (52) comprising a flow measuring device (187) connectable to an electrowinning cell (100).91 . The integrated process blower or exhaust fan (52) according to claim 90, wherein the blower or exhaust fan (52) has at least two operating set points which are configured to be controlled by an integrated and / or automated control panel (180).

92. The integrated process blower or exhaust fan (52) according to claim 90 or 91 , wherein the blower or exhaust fan (52) is configured to communicate with a vent (8) from the electrowinning cell (100), the vent (8) being configured to deliver off gas (41 ) from the electrowinning cell (100).

93. The integrated process blower or exhaust fan (52) according to any one of claims 90-92, wherein the blower or exhaust fan (52) is configured to communicate with a vent (8) from a barren solution return tank (5) communicating with the electrowinning cell (100), the vent (8) being configured to deliver off gas (41) from the barren solution return tank (5).

94. The integrated process blower or exhaust fan (52) according to any one of claims 90-93, wherein integrated process blower or exhaust fan (52) is configured to communicate with, provide off gas (41 ) to, or receive off gas (41 ) from a damper (53) configured to modulate flow of off gas (41) passing through a vent (8) that delivers off gas (41) from the electrowinning cell (100) and / or from a barren solution return tank (5).

95. An integrated process damper (53) configured to control expulsion of off gas (41 ) from an electrowinning cell (100) and / or barren solution return tank (5) of an electrowinning system (1 ), the integrated process damper (53) comprising a flow measuring device (187) connectable to an electrowinning cell (100).

96. The integrated process damper (53) according to claim 95, wherein the integrated process damper (53) has at least two operating set points which are configured to be controlled by an integrated and / or automated control panel (180).

97. The integrated process damper (53) according to claim 95 or 96, wherein the integrated process damper (53) is configured to communicate with, provide off gas (41 ) to, or receive off gas (41 ) from an integrated process blower or exhaust fan (52).

98. The integrated process damper (53) according to any one of claims 95-97, wherein the integrated process damper (53) is configured to modulate flow of off gas (41 ) passing through a vent (8) that delivers off gas (41 ) from the electrowinning cell (100) and / or from a barren solution return tank (5).

99. A retrofit kit for an electrowinn ing cell (100) comprising one or more components of a lifting system (107) which is configured to raise and lower an upper chassis (112) in relation to a frame (14) and / or tank (111 ) of an electrowinning cell (100), and / or which is configured to at least temporarily remove portions of at least one electrode (121 , 122) from submersion within a tank (111 ) of an electrowinning cell (100), the one or more components being configured to be installable onto and / or directly or indirectly integratable with a tank (111 ) of an electrowinning cell (100), the one or more components being selected from the group consisting of: an actuator (114), a guide (113), a drive motor (126), a movable upper chassis (112), a first part (112a) of a split movable upper chassis (112), a second part (112b) of a split movable upper chassis (112), a drive axle (142), a transmission (141 ), a gearbox (143), a screw rod (144), a ball screw drive (145), a drive coupling (146).

100. A method of retrofitting an electrowinning cell (100) comprising the step of: mounting and / or installing the one or more components of the lifting system (107) within the retrofit kit according to claim 99.

101. A retrofit kit for an electrowinn ing cell (100) comprising one or more components of a wash system (108) which is configured to clean at least one electrode (121 , 122) within a tank (111 ) of an electrowinning cell (100), the one or more components being configured to be installable onto and / or directly or indirectly integratable with a tank (111 ) of the electrowinning cell (100), the one or more components being selected from the group consisting of: a spray bar (147), a manifold (115), a feed pipe (116), a spray bar inlet (117), an end cap (163), a nozzle (150), filter outlet piping (35), a filter (11 ).

102. A method of retrofitting an electrowinning cell (100) comprising the step of: mounting and / or installing the one or more components of the wash system (108) within the retrofit kit according to claim 101.

103. The method according to claim 102, further comprising the step of: forming one or more holes into a sidewall portion of a tank (111 ) of the electrowinning cell (100).

104. A method of retrofitting an electrowinning cell (100) comprising the step of: providing one or more lifting systems (107) and / or one or more wash systems (108) to the electrowinning cell (100), using a retrofit kit according to claim 99 and / or claim 101 .

105. An electrode (121 ,122) for an electrowinning cell (100), such as an anode (121 ) or a cathode (122) comprising an electrically conductive generally planar central metallic portion, CHARACTERISED IN THAT it further comprises one or more integrated electrode electrical insulators (177, 178).

106. The electrode (121 ,122) according to claim 105, wherein the one or more integrated electrode electrical insulators (177, 178) comprises one or more flowrestricting baffles (178) which are each configured to protrude downwardly into a sludge collection trough above a sloped floor (129) within a tank (111 ) of an electrowinning cell (100).

107. The electrode (121 ,122) according to claim 106, wherein the one or more flow-restricting baffles (178) are triangular, chevron- shaped, or have edges which are configured to be spaced from and / or substantially parallel to the sloped floor (129).

108. The electrode (121 ,122) according to any one of claims 105-107, wherein the integrated electrode electrical insulators (177, 178) comprise one or more frame members (177) formed of an insulated material which are configured to surround or be arranged proximate peripheral edge portions of the electrically conductive generally planar central metallic portion.

109. The electrode (121 ,122) according to claim 108, wherein the integrated frame members (177) and baffles (178) are integral with one another.

110. The electrode (121 ,122) according to claim 108, wherein the integrated frame members (177) and baffles (178) are separable from one another.

111. The electrode (121 ,122) according to any one of claims 105-110, wherein the electrically conductive generally planar central metallic portion comprises a wire mesh or plate structure.

112. The electrode (121 ,122) according to any one of claims 105-108, further comprising an enlarged portion (155) adjacent an upper portion of the electrode (121 ,122) above the electrically conductive generally planar central metallic portion, wherein the enlarged portion (155) is configured to be received and / or retained within a complimentary receiving portion (154) of an electrode support hanger (123) of an electrowinning cell (100).

113. The electrode (121 ,122) according to claim 112, wherein the enlarged portion (155) is configured to be received in a receiving portion (154) of an electrode support hanger (123) transversely, substantially horizontally, or in a side-to-side or lateral sliding motion.

114. An electrode (121 ,122) for an electrowinning cell (100), such as an anode (121 ) or a cathode (122) comprising an electrically conductive generally planar central metallic portion, CHARACTERISED IN THAT it further comprises an enlarged portion (155) adjacent an upper portion of the electrode (121 ,122) above the electrically conductive generally planar central metallic portion, wherein the enlarged portion (155) is configured to be received and / or retained within a complimentary receiving portion (154) of an electrode support hanger (123) of an electrowinning cell (100).

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