Abstract: The present application relates to methods for the simultaneous leaching and extraction of precious metals. For example, the present application relates to methods of leaching and extracting gold and/or palladium from a substance comprising gold and/or palladium such as a gold- and/or palladium-containing ore in one step using a compound of Formula I:(I).

Abstract: Provided is a method for efficiently producing tungsten from a raw material mixture comprising at least one valuable containing tungsten. The present invention relates to a method for producing tungsten, comprising the steps of subjecting a raw material mixture comprising at least one valuable containing tungsten to electrolysis using an organic electrolytic solution to dissolve tungsten in the electrolytic solution; and calcining the electrolytic solution containing dissolved tungsten at a temperature of less than 800° C. to obtain tungsten.

Abstract: Provided is a method for efficiently producing tungsten carbide from a raw material mixture comprising at least one valuable containing tungsten. The present invention relates to a method for producing tungsten carbide, comprising the steps of subjecting a raw material mixture comprising at least one valuable containing tungsten to electrolysis using an organic electrolytic solution to dissolve tungsten in the electrolytic solution; and calcining the electrolytic solution containing dissolved tungsten at a temperature of 800° C. or more to obtain tungsten carbide.

Abstract: An apparatus for continuous simultaneous electroplating of two metals having substantially different standard electrodeposition potentials (e.g., for deposition of Sn—Ag alloys) comprises an anode chamber for containing an anolyte comprising ions of a first, less noble metal, (e.g., tin), but not of a second, more noble, metal (e.g., silver) and an active anode; a cathode chamber for containing catholyte including ions of a first metal (e.g., tin), ions of a second, more noble, metal (e.g., silver), and the substrate; a separation structure positioned between the anode chamber and the cathode chamber, where the separation structure substantially prevents transfer of more noble metal from catholyte to the anolyte; and fluidic features and an associated controller coupled to the apparatus and configured to perform continuous electroplating, while maintaining substantially constant concentrations of plating bath components for extended periods of use.

Abstract: The invention provides a stripping gold component which could remove gold from substrate, comprising: a stripping gold chemical compound; and a assistant conductive compound wherein said stripping gold chemical compound bonds with gold to form covalent bond to strip gold from said substrate, said assistant conductive chemical compound helps the electric conduction and decreases the voltage, said substrate would not be damaged after stripping gold from said substrate, and the stripping gold component is cyanide free.

Abstract: The present invention provides a process for recovering valuable metals from precious metal smelting slag, comprising: smelting the precious metal smelting slag and a flux in a top-blown rotary furnace to produce a lead-bismuth alloy, wherein the precious metal smelting slag comprises Au, Ag, Bi and Pb; electrolyzing the lead-bismuth alloy at a current density ranging from 60 to 110 A/m2 to obtain lead cathode and lead anode slime; refining the lead anode slime to produce bismuth and silver-zinc crust, and extracting gold and silver separately from the silver-zinc crust. Through utilizing a top-blown rotary furnace as the smelting apparatus and adjusting the ratio of the flux, the present invention enriches the valuable metals gold, silver, bismuth, lead or the like to lead-bismuth alloy, ensures lower contents of gold, silver, bismuth and lead in the reducing slag and thereby increases the comprehensive recovery rates of gold, silver, bismuth and lead from the precious metal smelting slag.

Abstract: Coaxial disk armatures, counter-rotating through an axial magnetic field, act as electrolysis electrodes and high shear centrifugal impellers for an axial feed. The feed can be carbon dioxide, water, methane, or other substances requiring electrolysis. Carbon dioxide and water can be processed into syngas and ozone continuously, enabling carbon and oxygen recycling at power plants. Within the space between the counter-rotating disk electrodes, a shear layer comprising a fractal tree network of radial vortices provides sink flow conduits for light fractions, such as syngas, radially inward while the heavy fractions, such as ozone and elemental carbon flow radially outward in boundary layers against the disks and beyond the disk periphery, where they are recovered as valuable products, such as carbon nanotubes.

Abstract: A method of preparing a metal containing inorganic ion exchanger in an electrochemical cell is disclosed. In one embodiment, the method comprises: (a) adding the inorganic ion exchanger to the electrochemical cell, wherein the electrochemical cell comprises a conductive electrolyte solution having a liquid phase and a solid phase; (b) depositing metal ions electrochemically into the liquid phase; (c) allowing the metal ions to deposit onto the inorganic ion exchanger during an electrochemical reaction to obtain a metal containing inorganic ion exchanger; (d) collecting the solid phase comprising the metal containing inorganic ion exchanger obtained in step (c); (e) removing remaining metal ions from the liquid phase; and (f) obtaining a substantially metal free liquid phase.

Abstract: The invention is directed to a method for producing metal-containing (e.g., non-oxide, oxide, or elemental) nano-objects, which may be nanoparticles or nanowires, the method comprising contacting an aqueous solution comprising a metal salt and water with an electrically powered electrode to form said metal-containing nano-objects dislodged from the electrode, wherein said electrode possesses a nanotextured surface that functions to confine the particle growth process to form said metal-containing nano-objects. The invention is also directed to the resulting metal-containing compositions as well as devices in which they are incorporated.

Abstract: The present invention provides a method for manufacturing silver triangular pyramid particles including: forming an electric field in an electrolytic solution including silver ions and a surfactant to reduce the silver ions into silver triangular pyramid particles.

Abstract: Methods and devices for the continuous manufacture of nanop?rticles, microparticles and nanoparticle/liquid solution(s) are disclosed. The nanoparticles (and/or micron-sized particles) comprise a variety of possible compositions, sizes and shapes. The particles (e.g., nanoparticles) are caused to be present (e. g., created) in a liquid (e.g., water) by utilizing at least one adjustable plasma (e.g., created by at least one AC and/or DC power source), which plasma communicates with at least a portion of a surface of the liquid. The continuous process causes at least one liquid to flow into, through and out of at least one trough member, such liquid being processed, conditioned and/or effected in said trough member(s).

Abstract: This invention relates generally to novel methods and novel devices for the continuous manufacture of nanoparticles, microparticles and nanoparticle/liquid solution(s). The nanoparticles (and/or micron-sized particles) comprise a variety of possible compositions, sizes and shapes. The particles (e.g., nanoparticles) are caused to be present (e.g., created and/or the liquid is predisposed to their presence (e.g., conditioned)) in a liquid (e.g., water) by, for example, preferably utilizing at least one adjustable plasma (e.g., created by at least one AC and/or DC power source), which plasma communicates with at least a portion of a surface of the liquid. At least one subsequent and/or substantially simultaneous adjustable electrochemical processing technique is also preferred. Multiple adjustable plasmas and/or adjustable electrochemical processing techniques are preferred.

Abstract: An electrochemical cell includes a container at atmospheric pressure comprising a liquid electrolyte and a first electrode at least partially immersed in the electrolyte. A plasma source is spaced apart from a surface of the electrolyte by a predetermined spacing, and a plasma spans the predetermined spacing to contact the surface of the electrolyte. A method of operating the electrochemical cell entails providing a first electrode at least partially immersed in a liquid electrolyte and producing a plasma in contact with a surface of the electrolyte at atmospheric pressure. The plasma acts as a second electrode, and a current is generated through the electrolyte. Electrochemical reactions involving at least the second electrode are initiated in the electrolyte.

Abstract: The present invention provides a method for manufacturing silver triangular pyramid particles including: forming an electric field in an electrolytic solution including silver ions and a surfactant to reduce the silver ions into silver triangular pyramid particles.

Abstract: In a method for producing metal powder, the first part of an acid-containing starting solution is fed on the anode side of an electrolytic cell as anolyte, to contact the anode and supply material containing yield metal, and a second part of the acid-containing starting solution, which also contains intermediary metal, is fed on the cathode side of the electrolytic cell, to contact the cathode as catholyte. Yield metal is oxidized and dissolved in the anolyte by leading electric current in the anode. The yield metal contained in the second part of the starting solution is reduced on the cathode side. Anolyte solution and catholyte solution are fed to a precipitating chamber for mixing the dissolved, oxidized yield metal and the second part of the starting solution containing reduced intermediary metal.

Abstract: An extraction component enabling the concurrent recovery of gold and/or palladium selectively from a hydrochloric acid media containing the base metals and other contaminants. The disclosed extractant disclosed eliminates the conventional multi-step process for such extraction by providing for an extraction method which uses a single solvent extraction reagent. Further enhancing the conventional multi step process, the conventional scrubbing stage is eliminated by a single stripping stage. The resulting solutions can be obtained from leaching many types of material such as copper anode slimes, the treatment of scrap such as electronic circuit boards and plating effluents, PGM, or refractory gold ores.

Abstract: Apparatus and processes are disclosed for electrowinning metal from a fluid stream. A representative apparatus comprises at least one spouted bed reactor wherein each said reactor includes an anolyte chamber comprising an anode and configured for containing an anolyte, a catholyte chamber comprising a current collector and configured for containing a particulate cathode bed and a flowing stream of an electrically conductive metal-containing fluid, and a membrane separating said anolyte chamber and said catholyte chamber, an inlet for an electrically conductive metal-containing fluid stream; and a particle bed churning device configured for spouting particle bed particles in the catholyte chamber independently of the flow of said metal-containing fluid stream. In operation, reduced heavy metals or their oxides are recovered from the cathode particles.

Abstract: Provided is a method and apparatus for producing silver nanoparticles in uniform shape and size using an electrolysis eco-friendly and in a simple way.

Abstract: Provided are a low impedance gold electrode, which has increased surface area, and can improve a bonding force with other materials, an apparatus for and a method of fabricating the low impedance gold electrode, and an electrolyte solution for use in the fabrication of the low impedance gold electrode. The gold electrode has a surface roughness that is increased through electrolysis using an acid electrolyte solution, has an impedance that is less than 1/10 of an impedance before the electrolysis and is higher than 0? when the low impedance gold electrode is disposed in the acid electrolyte solution or another electrolyte solution, and has a single-layered structure whose thickness is less than that before the electrolysis.

Abstract: This invention relates generally to novel methods and novel devices for the continuous manufacture of nanoparticles, microparticles and nanoparticle/liquid solution(s) (e.g., colloids). The nanoparticles (and/or micron-sized particles) comprise a variety of possible compositions, sizes and shapes. The particles (e.g., nanoparticles) are caused to be present (e.g., created and/or the liquid is predisposed to their presence (e.g., conditioned)) in a liquid (e.g., water) by, for example, preferably utilizing at least one adjustable plasma (e.g., created by at least one AC and/or DC power source), which plasma communicates with at least a portion of a surface of the liquid. At least one subsequent and/or substantially simultaneous adjustable electrochemical processing technique is also preferred. Multiple adjustable plasmas and/or adjustable electrochemical processing techniques are preferred. Processing enhancers can be utilized alone or with a plasma. Semicontinuous and batch processes can also be utilized.

Abstract: Disclosed herein is a method for concentrating gold contained in a leach residue obtained in a copper hydrometallurgical process for recovering copper from a copper sulfide mineral to efficiently separate and recover gold from the leach residue: a gold-bearing copper sulfide mineral is subjected to pressure leaching with sulfuric acid at a temperature higher than 102° C. and 112° C. or lower to obtain a leach residue, and the leach residue is subjected to flotation to separate it into a float fraction and a sink fraction; the float fraction obtained by flotation is desulfurized to obtain a desulfurized product; the desulfurized product is subjected to oxidative roasting to obtain an oxidatively-roasted product; the oxidatively-roasted product is dissolved in a sulfuric acid solution to obtain a copper solution, and a gold-bearing residue is separated and recovered from the copper solution.

Abstract: The present invention is directed to flotation of refractory gold sulfide ores in which the ore is ground, floated, the tailings reground, and refloated to produce gold-bearing concentrates.

Abstract: The invention relates to a method for recovering gold from a sulphidic concentrate, particularly one containing arsenopyrite and/or pyrite, hydro-metallurgically. The concentrate is first subjected to leaching with a concentrated solution of alkali chloride and copper (II) chloride, by means of which the copper minerals and some of the gold in the concentrate are made to dissolve. Elemental sulphur and precipitated iron and arsenic compounds are separated from the leaching residue using physical separation methods, whereby the first intermediate is obtained, which contains gold-bearing sulphide minerals and gangue minerals as well as the gold that remains undissolved. The free gold that remains undissolved is separated by means of gravity separation methods. After gravity separation, additional comminution is carried out, after which the sulphide minerals are decomposed and the gold-containing solution or residue is routed to the concentrate leaching circuit.

Abstract: In a stable gold plating liquid having a low toxicity besides properties comparable to those of a cyan-type gold plating liquid, iodine and/or iodide ions, gold ions, and a polyalcohol having at least 4 carbon atoms are contained. The polyalcohol having at least 4 carbon atoms may be diethylene glycol or triethylene glycol. The content of the polyalcohol having at least 4 carbon atoms in the gold plating liquid is generally 10 to 90 percent by weight. The gold plating liquid may contain water.

Abstract: This invention relates to an improved electrochemical process for winning platinum group and incidental precious metals from ore. The process utilizes a peroxide leach in combination with electricity to produce higher valency metals and comprises the following steps: combining ground ore with a solution comprising water with a selected amount of H2O2 and an anion source to form a slurry; applying a direct current while allowing the metal in the ore to leach into the solution for a selected period of time; filtering and clarifying the leached slurry to obtain a pregnant solution; and treating the pregnant solution to yield metal, metal salts or both.

Abstract: The present invention provides a method for manufacturing silver triangular pyramid particles including: forming an electric field in an electrolytic solution including silver ions and a surfactant to reduce the silver ions into silver triangular pyramid particles.

Abstract: A method of producing a higher purity metal comprising the step of electrolyzing a coarse metal material by a primary electrolysis to obtain a primary electrodeposited metal, the step of electrolyzing the material with the primary electrodeposited metal obtained in the primary electrolysis step used as an anode to obtain a higher purity electrolyte for secondary electrolysis, and the step of further performing secondary electrolysis by employing higher purity electrolytic solution than said electrolytic solution with said primary electrodeposited metal as an anode, whereby providing an electro-refining method that effectively uses electrodes and an electrolyte produced in a plurality of electro-refining steps, reuses the flow of an electrolyte in the system, reduces organic matter-caused oxygen content, and can effectively produce a high purity metal.

Abstract: An apparatus and method for producing colloidal silver. A large-volume container, such as a fifteen gallon container, includes a hinged lid on which a rotational impeller is mounted along with several sets of electrodes that are electrically connected to a power transformer. The container is partially filled with water, and when the lid is closed, the sets of electrodes are disposed in communication with the water in a predetermined arrangement, and the impeller resides submerged in the water. Certain of the electrodes constitute silver wire. The power transformers convey current to the electrodes, preferably alternating current, at voltages sufficient to cause silver particles to separate from the silver wire and enter the solution in a stable, suspended state. The impeller is rotated, preferably continuously, to prevent the suspended silver from remaining in upper levels of the water, thereby dispersing the silver particles more uniformly throughout the volume of water.

Abstract: An apparatus and method utilizing a strip solution for removing gold from the loaded activated carbon used to accumulate such gold leached from gold bearing ore, and for electrically removing such gold from the strip solution by electrowinning. The apparatus includes a pair of strip columns fillable with loaded activated carbon. The strip columns are connectable individually and in series in respective continuous loops using a valved crossover pipe assembly to an electrowinning device, with the strip solution being pumped therethrough.

Abstract: A method of preparing organic acids (fulvic, humic, and ulmic) for use as an electrolyte for producing high ionizations of precious metals (such as silver) which entails leaching out the organic acid from its source, stabilizing the organic acid first with ascorbic acid followed by sodium benzoate, removing cations, and using the organic acid as an electrolyte. A precious metal (such as silver) is used as a sacrificial electrode in this electrolyte. A non-sacrificial electrode could either be the same precious metal or an inert non-precious metal (titanium or graphite carbons). If the same material is used for the non-sacrificial electrode as for the sacrificial electrode, the size of each electrode may be about the same. If different material is used for the non-sacrificial electrode, its size should be larger that of the sacrificial electrode. Current at about 2 or more volts is applied to the electrodes and the ionization process begins yielding high concentrations of ionized precious metals.

Abstract: This invention relates to an electrolytic method for the selective recovery and recycling of silver from a nitric acid solution containing it in the form of Ag(I), this method comprising successive steps of electro-deposition of the silver in the form of silver metal Ag(0), and then of redissolution of the deposited silver Ag(0), to give a final solution of Ag(I) in which the step of electro-deposition is carried out at a prescribed current and the successive steps of electro-deposition of the silver and of redissolution of the deposited silver are carried out in the same apparatus. The invention is applicable particularly to the selective recovery of Ag(I) by reduction to Ag metal from nitric acid solutions arising from the processing of plutonium containing waste in plants for the reprocessing of nuclear fuels and to the redissolution of the silver metal to form Ag(I) with the purpose of recycling it to an upstream point of the method.

Abstract: The invention relates to a method for controlling the recovery of a metal, such as silver, from a solution flowing through an electrolytic cell. A constant current is applied between the anode and cathode of the cell and the rate of change of the voltage monitored, the information obtained from the monitored change of voltage being used to control the rate of recovery of the metal.

Abstract: An electrolytic cell for the recovery of silver from a photographic fixer solution is of generally cylindrical configuration. The cell has a screw-on lid that carries the disposable cathode of the cell. Inlet and outlet for the solution are at the bottom of the cell. The anode is tubular and extends upwardly from the outlet at the base of the cell towards the lid. The cathode is easily replaced, together with the lid, and flow through and the dimensions of the cell are arranged to avoid entrapment of gas therein.

Abstract: A method for manufacturing a metal composite strip for the production of electrical contact components. A film made of tin or a tin alloy is first applied onto an initial material made of an electrically conductive base material. A film of silver is then deposited thereonto. Copper or a copper alloy is preferably used as the base material. The tin film can be applied in the molten state, and the silver film by electroplating. Furthermore, both the tin film and the silver film can be deposited by electroplating. A further alternative provides for manufacturing the tin film in the molten state and the silver film by cathodic sputtering. The diffusion operations which occur in the coating result in a homogeneous film of a tin-silver alloy. This formation can be assisted by way of a heat treatment of the composite strip.

Abstract: The present invention is directed to a process for removing various contaminants (e.g., organic collectors, contaminant metals or spectator ions, and/or suspended and colloidal solids) from process streams in leaching processes. The contaminant removal is performed by one or more membrane filtration systems (e.g., nanofilters, ultrafilters, and/or microfilters) treating process streams including, the pregnant leaching solution, the barren raffinate, and the lean and rich electrolytes.

Abstract: A high performance method for recovery of metal from aqueous solutions is carried out using an electrochemical cell having a cathode assembly that includes a nonporous support member, a primary cathode, and a nonconductive or conductive porous material covering the primary cathode. An anode is spaced apart from the cathode assembly. Fluid is caused to flow through the porous material to the primary cathode, through openings or fluid collection channels in the nonporous support member, and uniformly out of the cell. Uniform and efficient deposition of metal is accomplished over the entire cathode assembly because of modulation of fluid flow and increased mass transfer.

Abstract: A method for refining noble metals has a silver treating process including a nitric acid leaching step of silver, a purification step of the leaching solution, an electrolytic decomposition step of silver, and a recycling step after the electrolytic decomposition, wherein in the purification step, lime is added in order to precipitate the metallic impurities, such as selenium, tellurium, bismuth, and copper, by neutralization of the leaching solution, and in the recycling step, sulfuric acid is added to the solution after electrolytic decomposition to regenerate nitric acid for recycling use by precipitation of calcium in the solution as gypsum. Preferably, the refining method has a gold recovery process, as well as the silver treating process, wherein the residue of the nitric leaching of the crude silver is dissolved by chlorination and gold is recovered from the leaching solution by solvent extraction or reductive precipitation.

Abstract: An electrolytic cell comprises a housing (12), means (21) defining a liquid level (25) in said housing (12), a first contact surface (32) positioned above said liquid level (25) for making contact with a removable electrode (20) when positioned in said housing (12). A second contact surface (36) is positioned above said liquid level (25) and electrically isolated from said first contact surface (32) for making contact with said removable electrode (20) when positioned in said housing (12). A method of electrolysis in such a cell comprises supplying electrical power to said electrode (20) at an electrolysing potential (U.sub.P) and controlling the electrolysing potential (U.sub.P) in response to the potential (U.sub.2) sensed at the second contact surface (36). Control of the electrolysis process is possible without influence of any unknown and variable resistance between the first contact surface and the electrode.

Abstract: A highly sensitive sensor for the amperometric assay of glucose in aqueous media having a face-to-face sandwich configuration is provided which comprises a sensing electrode strip containing a first redox mediator in an electrically conductive coating and a reference electrode strip in simultaneous contact with a reagent strip containing a second redox mediator which is sandwiched between the active electrode surfaces. An opening is provided in the reference electrode for the introduction of samples. In one embodiment, a whole blood separation membrane is interposed between the reference electrode and the reagent strip to filter red blood cells and other particles from whole blood to enable direct assay of glucose without sample preparation. The sensing electrode comprises a non-conductive support member having an electrically conductive layer containing the first redox mediator.

Abstract: Disclosed is a method for reducing metal acid or salt evolved from electrolytic baths housed in electrolytic tanks during electrolytic operations. This method involves covering all of the surface of the electrolytic bath with a layer of shredded foam (e.g., polymeric foam, metal foam, glass foam, or vitreous material foam). The shredded foam is irregular in shape, lacking in uniform particle size, is inert to the electrolytic operation, and floats at the surface of the electrolytic bath. Desirably, the layer of shredded foam is about 3 to 4 inches (76-102 mm) in thickness. Examples of specific processes benefiting from the present invention are anodizing, electroplating, electrowinning, and electrophoresis operations.

Abstract: An apparatus for de-silvering silver-containing solutions comprises an electrolytic cell (10) having an anode (20), a cathode (30) and a reference electrode (45) positioned adjacent the cathode (30), and electrical power supply control means (41) for controlling the supply of electrical power to the anode (20) and the cathode (30). Operation of the cell (10) is controlled potentiostatically while the current exceeds a certain threshold value and the current is controlled galvanostatically at that threshold (minimum) value in circumstances in which the potentiostatic control would result in a current below the threshold value.

Abstract: An electrochemical apparatus and system for extracting and recovering metals from their compounds using electrochemical cells where the anolyte 10 is connected electrically to the catholyte 11 through an independent set of electrodes 13, 14 immersed in each electrolyte and connected to each other by a conductor 16. The specification details the application of this principle to commercial size cells and systems to extract metals from solutions, from ores in-situ, from ores in heaps and fixed beds, from fine metal concentrates dissolved either at the anode cell or in a separate leaching vessel. Alkaline electrolytes are also given for the extraction and recovery of nickel and copper from their oxide ores. A method for extracting gold from ores or residues is also included.

Abstract: Ores containing copper, zinc, silver in the form of sulfides are treated by a solution of sulfurated sulfite ions and ammonium ions in order to remove most of the metals from the sulfide ores. This treatment renders the resulting gold bearing ores much more amenable to cyanide extraction. Dissolved metals are reclaimed by appropriate techniques, such as electrowinning or liquid-liquid extraction, and the solution of sulfurated sulfites and ammonia is recycled for further lixiviation of fresh ores.

Abstract: An amperometric glucose biosensor having high sensitivity and accuracy over a wide range of glucose concentrations and a method for the rapid detection of glucose in urine are provided. The biosensor strip comprises an electrically conductive carbon layer, having a first redox mediator, a reagent strip containing an enzyme system for the oxidation of glucose and a second redox mediator, and a silver/silver chloride reference electrode. In a preferred form of the sensor that has high sensitivity, a sensing electrode and a reference electrode are arranged so that the electrically conductive layers of the electrodes are face-to-face and sandwich the reagent strip between them. Screening for glucose is achieved by contacting the sensor with a drop of the patient's urine and comparing the current read-out with a standard calibration curve or by automatically converting the current flow generated by the test sample to units of glucose concentration. The sensor can measure urine glucose concentrations below 3 mg/dl.

Abstract: An apparatus for desilvering silver-containing solutions comprises an electrolytic cell (10) having an anode (20), a cathode (30) and a reference electrode (45) positioned adjacent the cathode (30), and electrical power supply control means (41) for controlling the supply of electrical power to the anode (20) and the cathode (30). The power supply control means (41) includes means (60) for adjusting the cathode potential and control means (70) linked to said adjustment means (60) to reduce the cathode potential, at least periodically, as the desilvering process continues. The process leads to better silver adhesion on the cathode occurs, while maintaining good desilvering levels in the solution, and cathode poisoning is minimised.

Abstract: A silver-containing solution is de-silvered in an electrolytic cell having an anode and a cathode. The diffusion limitation current density of the electrolytic cell is estimated by measuring a current flow there-through and silver is deposited on the cathode at a de-silvering current density which is lower than the diffusion limitation current density.

Abstract: In the recovery of an electrically conductive metal from a liquid containing the metal in solution, a cathode member for deposition of the metal by electrolysis, comprises a carrier sheet with a cathode element of the metal to be recovered, on one side of the sheet; the carrier sheet is of a material from which the metal is readily refinable when smelted with the carrier sheet; the cathode member has particular application for removal of the silver content of fixer solution in photography; suitably the sheet is flexible and has a memory of a planar state, such that on being rolled into a cylindrical tubular configuration, it returns to the planar state unless restrained.

Abstract: An electrochemical cell is provided for removal of metals such as copper, lead, silver, tellurium, platinum, palladium or nickel from dilute solutions of the metal. The cell comprises a porous tubular support (18) which is provided with a cathode comprising a porous carbon fiber material (19), a current feeder (15) for the cathode, a tubular anode (12) spaced from said cathode, a current feeder (16) for the anode, the anode and the cathode being enclosed by a non-porous outer casing (11). In use the dilute solution from which the metal is to be removed is introduced into the cell through an inlet (13) and flows through the porous carbon fiber cathode to an outlet (14). The cell is useful for removing harmful metals from wastes so that they are environmentally acceptable for disposal and for recovery of valuable metals.

Abstract: An apparatus for de-silvering a silver-containing solution, comprises a plurality of electrolysis cells (10, S1, S2) each having an anode (20, 120, 220) and a cathode (30, 130, 230). A master cell (10) further comprises a reference electrode (45). The remaining cell or cells constitute slave cells (S1, S2). Control means (41) adjust the cathode potential applied to the slave cells (S1, S2) in response to the current flow (I.sub.M) through the master cell (10). The apparatus is particularly suitable for de-silvering large volumes of silver-containing solution, without the use of high currents.

Abstract: A method of treating a solid material containing a substance of economic importance so as to recover or extract the substance from the material involving the following: forming a conducting mixture of the solid with a liquid so that at least some of the substance of economic importance is dissolved in the liquid, applying an electrical potential difference between at least two electrodes in contact with the mixture at spaced apart locations so as to impart opposite charges to the respective electrodes thereby attracting the liquid containing the dissolved substance to one of the electrodes, removing the liquid from an area surrounding or from a vicinity of the one electrode, and treating the liquid containing the substance of economic importance so as to recover or extract the substance. The liquid used is at least partially conducting. The present method is particularly useful for extracting or recovering gold from gold-containing or gold bearing ores.