Abstract: The invention related to a method for extracting tin and/or lead contained in an electrically conductive mixture derived from waste, using a solution comprising methane sulphonic acid as an electrolytic solution.

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: The present invention relates to an electrolytic process for producing metallic lead starting from desulfurized lead pastel comprising the following operative phases: a) leaching the desulfurized pastel by putting it in contact with a solution comprising ammonium chloride, with the formation of a leach liquor and evolution of gaseous CO2; b) separating a first solid residue and a first clarified leach liquor from the leach liquor coming from phase a); c) leaching the solid residue separated in phase b) by putting it in contact with a solution comprising ammonium chloride and hydrogen peroxide; d) separating a second solid residue and a second clarified leach liquor from the leach liquor coming from phase c); e) joining the first clarified leach liquor coming from phase b) with the second clarified leach liquor coming from phase d) and forming a single solution; f) subjecting the solution leaving phase e) to electrolysis in a flow cell, with a current density ranging from 50 to 10,000 A/m2, said electrolysis r

Abstract: The invention relates generally to a process for removing one or more contaminants from an electrolytic solution and more particularly to a process for removing the one or more contaminants contained in an electrorefining solution using rare earth metals.

Abstract: A system for producing metal particles using a discrete particle electrolyzer cathode, a discrete particle electrolyzer cathode, and methods for manufacturing the cathode. The cathode has a plurality of active zones on a surface thereof at least partially immersed in a reaction solution. The active zones are spaced from one another by between about 0.1 mm and about 10 mm, and each has a surface area no less than about 0.02 square mm. The cathode is spaced from an anode also at least partially immersed in the reaction solution. A voltage potential is applied between the anode and cathode. Metal particles form on the active zones of the cathode. The particles may be dislodged from the cathode after they have achieved a desired size. The geometry and composition of the active zones are specified to promote the growth of high quality particles suitable for use in metal/air fuel cells. Cathodes may be formed from bundled wire, machined metal, chemical etching, or chemical vapor deposition techniques.

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: The present invention relates to a method for treating spent tin or tin/lead stripping solution used in the electronic industry, particularly in the manufacture of printed circuit boards or a lead frames. Said method comprises (i) electrolytically reducing copper ions in the solution to copper at a low temperature; (ii) electrolytically oxidizing Sn2+ and Pb2+ in the solution at a high temperature to form solid tin and lead oxides and hydroxides; (iii) separating solid tin and lead oxides and hydroxides from the solution; (iv) dissolving tin and lead oxides and hydroxides obtained in step (iii) in a strong alkali or acidic solution; and (v) electrolytically reducing the alkali or acidic solution obtained in step (iv) at a high temperature to recover metallic tin and lead. Also, the filtrate obtained in step (iii) above is useful for preparing fresh tin or tin/lead stripping solution.

Abstract: Various systems and methods for protecting electrowinning anodes having electrocatalytically active coatings in a bank of electrolytic cells from being damaged by reverse currents. In the first embodiment, one or more auxiliary power sources are provided that, when triggered by one or more predetermined conditions being met, keep the bank of electrolytic cells in an electrical state that is relatively harmless to the anodes having electrocatalytically active coatings. In a second embodiment, the invention is directed to a method of maintaining the polarization of anodes in an electrowinning cell positive of the cathodes (i.e. in a potential region where the anode coating is not susceptible to significant damage). In a final embodiment, the invention is directed to various methods for the installation of replacement anodes and maintenance of electrowinning cells.

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: 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 electrolytic cell comprising bipolar electrodes is employed for electrochemical deposition of copper, zinc, lead, nickel or cobalt. An interior space is provided between the cathode side and the anode side of a bipolar electrode. The electrolyte can flow substantially without an obstruction through the interelectrode space between adjacent electrodes. The current densities in the interelectrode space amount to 800 to 8000 A/m.sup.2. Gas is evolved on the anode side of the bipolar electrodes and causes liquid to flow along the anode side. In the middle of the height of the anode side that liquid flow has a vertical component having a velocity of 5 to 100 cm/second. Electrolyte solution flows from the upper edge portion of the anode side to a return flow space, in which the solution flows downwardly. From the return flow space the solution is returned to the lower portion of the interelectrode space.

Abstract: The object of the invention is a method for the electrochemical preparation of metal colloids with particle sizes of less than 30 nm, characterized in that one or more salts of one or more metals of groups Ib, IIb, III, IV, V, VI, VIIb, VIII, lanthanoides, and/or actinoides of the periodic table are cathodically reduced in the presence of a stabilizer, optionally with a supporting electrolyte being added, in organic solvents or in solvent mixtures of organic solvents and/or water within a temperature range of between -78.degree. C. and +120.degree. C. to form metal colloidal solutions or redispersible metal colloid powders, optionally in the presence of inert substrates and/or soluble metal salts of the respective metals. The invention further relates to soluble or redispersible colloids as well as application on substrates and immobilization thereof, in particular for the preparation of catalysts.

Abstract: A process for the direct recovery of metallic lead from battery paste in an electrolysis unit is disclosed. The electrolysis unit consists of an anode compartment and a cathode compartment separated by an ion selective membrane. The cathode consists of a high surface area electrically conductive substrate. Solid particles of battery paste are introduced into the cathode compartment which contains a liquid electrolyte and a complexing agent. Metallic lead is electrochemically deposited on the cathode, and sulfuric acid is produced in the anode compartment.