Abstract: A process for electroplating metals in an electroplating cell in which the anode current efficiency of the cell is greater than the cathode current efficiency. Buildup of excess metal in the cell is counteracted by circulating the plating solution through an electrowinning cell and plating out the excess metal onto cathodes in the electrowinning cell. The amount of current flowing through the electrowinning cell is controlled so that the amount of the said current which results in the deposition of metal is at least substantially equal to the amount of current flowing through the electroplating cell which results in the evolution of hydrogen gas.

Abstract: Disclosed are processes and an apparatus for refining gold. One of the processes comprises dissolving unrefined gold by use of iodine and/or an iodide compound to form a solution containing an iodide compound of gold, removing insoluble substances in the solution, reducing the ions containing the gold by use of an alkali to precipitate the gold of high purity. In this process, the iodine may be obtained by electrolyzing the iodide compound. The other process and the apparatus further comprise circulating the solution having been separated from the precipitated gold for reuse, and the alkali simultaneously produced by the above electrolysis is economically employed therein.

Abstract: The invention resides in an apparatus for the decontamination of radioactivated metallic waste by the electrolytic oxidation-reduction with an aqueous nitric acid solution containing trivalent cerium ions, i.e. the step of converting the trivalent cerium ions into tetravalent cerium ions through electrolytic oxidation and the step of dissolving the surface layer of the radioactivated metallic waste by oxidizing it with the electrolytic solution now vested with the oxidative power of the freshly produced tetravalent cerium ions and, at the same time, effecting regeneration of the tetravalent cerium ions.

Abstract: Chlorine dioxide is produced by electrolysis of a solution of chlorite and by using a compact apparatus which provides continuously a uniform concentration of chlorine dioxide, which can be operated easily, which discharges a spent electrolyte that can be treated easily and which achieves highly efficient use of chlorite and high current efficiency.

Abstract: The gold content of a gold plating bath is replenished by circulating the plating solution through an AuCN containing vessel. The plating solution contains sufficient free cyanide to render the gold soluble by producing the soluble Au(CN).sub.2.sup.- ion.

Abstract: A metal strip is electrolytically treated by using an apparatus having:a vessel for defining an electrolytic treatment space for a metal strip;a plurality of conductor rolls arranged along a path of movement of the metal strip extending through the treatment space;at least one pair of electrode pads, each pair of electrode pads being located between two conductor rolls and being spaced from and facing each other with the path of movement of the steel strip therebetween, and each pad being provided with at least one slit through which an electrolyte is ejected toward the surface of the metal strip under conditions adquate for creating a static pressure of the ejected electrolyte sufficiently high for holding the metal strip in its path in the gap between the electrode pad and the metal strip, and;a voltage supply for applying voltage between at least one of the conductor rolls and the electrode pads.

Abstract: An electroforming or electrodeposition system in which the depleted metallic component in the electrolyte is replenished by an electrolyzing unit having an anode chamber communicating with the electroforming electrolyte receptacle and separated by an ion-exchange membrance from a cathode chamber. An anode in the anode chamber is dissolved electrolytically to furnish the metallic component. The electroforming current is measured to indicate the rate of depletion of the metallic component from the electroforming electrolyte, the measurement signal being used to control the electrolyzing current to dissolve the metallic component from the anode so that the ionic concentration of the metal in the receptacle is maintained substantially constant.

Abstract: A method for the electrolytic tinning of steel strip in an electrolytic bath wherein the steel strip is the cathode and insoluble anodes are used, the electrodes are immersed in an electrolyte solution containing tin ions and wherein the concentration of the tin ions in the bath is controlled by passing the solution exterior of the bath in contact with tin in particulate form, while simultaneously maintaining a high content of dissolved oxygen in the solution. This latter treatment replenishes the tin concentration of the solution and the thus replenished electrolytic solution can be returned to the bath in a manner so as to consistently maintain the tin ion concentration at the desired level.

Abstract: An apparatus used in the electrodeposition coating of a continuous sheet of metal as it travels in a horizontal pathway between a pair of electrically charged electrodes and through a bath of liquid coating solution that is continuously circulated to the bath through a pair of liquid seals which are disposed adjacent opposing, aligned openings through which the sheet of metal enters and exits a chamber containing the bath. The liquid seals are each comprised of a pair of nozzles for directing converging streams of liquid coating solution against the traveling sheet of metal in the direction of the chamber and have a three-fold purpose.

Abstract: Apparatus for producing high purity oxygen comprising an oxidizing reactor coupled to at least one compartment of an electrochemical cell. Air is used to oxidize a reduced form of a special compound to form a peroxide which spontaneously decomposes to a mixture of the oxidized form of said compound and hydrogen peroxide. This mixture is positoned in the anode compartment of said cell and oxidized to cause the hydrogen peroxide to give off oxygen which is removed and recovered. The oxidized form of said compound is transferred to the cathode compartment wherein it is reduced and then recycled to the oxidizing reactor. The apparatus also provides a filter press-type cell containing a plurality of side-by-side compartmented electrochemical cells formed by alternating bipolar electrodes separated by porous membranes.

Abstract: A chromic-sulfuric etching solution for copper is regenerated in an etching container with a permeable diaphragm dividing the container into an etching chamber and a sulfuric acid containing chamber. Electric current passes between an anode electrode located in the etchant chamber and a cathode electrode located in the sulfuric acid chamber to regenerate the etchant in the anode containing chamber and to deposit copper on the cathode.

Abstract: Aluminum or an alloy thereof is electroplated upon electrically conductive substrates by immersing the substrate as a cathode in a novel stable electrolyte, made as follows:A. reacting aluminum with a hydrogen halide such as HCl, HBr, or HI (but preferably hydrogen bromide) or reacting aluminum with a halogen such as Cl.sub.2, Br.sub.2, or I.sub.2 (but preferably bromine), in the absence of water, but in one of the following single organic, non-Lewis base solvents or mixtures thereof: benzene, toluene, carbon disulfide, cyclohexane, dimethyl sulfide, tetrahydrofuran, diiodoethane, toluene-cyclohexane (1:1), benzene-cyclohexane (1:1), tetrahydrofuran (THF): benzene (4:1) and toluene-CS.sub.2 (3:1) to form an intermediate aluminum halide cation in solution, the concentration of the aluminum cation and the concentration of hydrogen ion, in solution being respectively, below about 7.5 M and 0.5 M and preferably being, respectively, below about 4.2 M and 0.1 M; andB.

Abstract: Portable apparatus is disclosed for recovering metal from metal bearing solutions. The apparatus includes a chamber arranged to be mounted on a container for the solution to establish a fluid flow path between an anode and cathode in the chamber for deposition of metal on the cathode, the unit being arranged to prevent unauthorized removal of deposited metal from the cathode.

Abstract: Excellent high speed nickel plating is achieved by using insoluble anode, detecting changes in the pH value of the plating bath during the plating operation, and supplying nickel ions to the plating bath in response to the detected changes by forcibly contacting the plating bath with metallic nickel pieces.

Abstract: A silver recovery apparatus for use in conjunction with photographic development systems acting to remove metallic silver from the hypo bath. The present device includes an electrolytic cell within a closed chamber through which the hypo bath is bypassed. The silver contaminated hypo solution is passed through the electrolytic chamber with a uniform velocity and is distributed uniformly over an extended cathode surface without any moving parts within the chamber. This uniformity of velocity and distribution causes maximum deposition of silver onto the cathode so that the hypo solution returning to the development and fixing process is considerably rejuvenated and continues to operate at high efficiency.

Abstract: An electrolytic cell comprising a rectangular tank divided into a plurality of adjacent compartments by a plurality of spaced apart parallel electrode plates. The outboard electrodes may form one pair of the opposite tank walls. Alternate electrodes are of opposite polarity. The intermediate electrodes terminate short of the tank ends so that the slurry or solution may pass around both ends of the electrode. An agitator is mounted in each compartment. The agitators are shaped and positioned to direct a predetermined volume of slurry against each electrode, the amount being directed against the cathode and anode respectively may be equal or unequal depending on the metal being recovered and the chemical reaction required at the electrode.

Abstract: A process and apparatus for purification of a sodium chloride solution dialysis liquid in which the liquid is subjected to an electrolysis.

Abstract: The invention comprises improvements in inert anode electroplating processes that make possible the utilization of typically inexpensive and otherwise advantageous cation-yielding compounds for replenishing the plating bath, compounds that typically are not well suited for such use in prior art systems due to their relatively low dissolution rate which typically requires their use in powder form, and the tendency of the powder particles to aggregate. Exemplary applications for the improved plating process are in Cu-, Ni-, and Pd-plating, and exemplary cation-yielding compounds or CuO, NiO, PdO, Cu(OH).sub.2,Ni(OH).sub.2, and Pd(OH).sub.2. The improvements according to the invention comprise agitating the powder/electrolyte mixture or slurry in a reactor vessel separate from the plating tank, and maintaining the cation concentration in the plating tank within predetermined limits. Agitation typically requires power input to the slurry of at least about 2.