Abstract: Systems are described for dissolving metal silicates to: produce metal hydroxide; remove carbon dioxide or other acid gases from the atmosphere or other gas mixture by reacting such gases with the metal hydroxide; penetrate or excavate metal silicates; extract metals or silicon-containing compounds from metal silicates; and produce hydrogen and oxygen or other gases.

Abstract: Systems are described for dissolving metal silicates to: produce metal hydroxide; remove carbon dioxide or other acid gases from the atmosphere or other gas mixture by reacting such gases with the metal hydroxide; penetrate or excavate metal silicates; extract metals or silicon-containing compounds from metal silicates; and produce hydrogen and oxygen or other gases.

Abstract: An electric current is passed through an acidic solution containing one or more soluble metal salts in an electrolytic cell divided by an anion exchange membrane. The acidic solution is fed into the cathode compartment whereby the passage of electric current at sufficient voltage causes the generation of hydrogen at the cathode. This gives rise to a localized very highly polarized region at the cathode resulting in a localized effective high relative pH. This causes the metal cation species to precipitate as a hydroxide (or oxide) species and electroadsorption/electrocoagulation causes the finely precipitated hydroxide (or oxide) species to adhere to the cathode. Electrodialytic transport of the liberated acid anions across the anion exchange membrane selectively removes the acid anions. Oxygen and hydrogen ions are formed by hydrolysis as the counter-reaction at the anode. Hydrogen ions combine with the anions to regenerate sulfuric acid.

Abstract: The invention relates to a method for producing metal hydroxides or alkaline metal carbonates by anode dissolution of the corresponding metals and precipitation of the hydroxides or alkaline carbonates in an aqueous medium. The anode dissolution of the metal components is carried out in the anode compartment of a three-compartment electrolytic cell. An aqueous auxiliary salt solution is fed to an intermediate compartment that is disposed between the anode compartment and the cathode compartment and that is separated therefrom by a porous membrane. An at least not alkaline metal salt solution is continuously taken from the anode compartment while an alkaline auxiliary salt solution is continuously taken from the cathode compartment. The at least not alkaline metal salt solution and the alkaline auxiliary salt solution are combined outside the electrolytic cell for the purpose of precipitating metal hydroxides or alkaline metal carbonates.

Abstract: A method for the electrochemical production of ferrate salts in an aqueous electrolyte solution comprising one or more hydroxide components. Dramatically increased yields of ferrate salts are obtained from using a mixture of sodium hydroxide and potassium hydroxide. Preferably, both sodium hydroxide and potassium hydroxide are present in concentrations greater than 5 molar, most preferably at least 10 molar, i.e., 10 M NaOH and 10 M KOH. The anode is preferably a sacrificial anode made out of an iron-containing material to supply the iron necessary for the ferrate production reaction.

Abstract: A process is described for the production of spherical nickel hydroxide by anodic dissolution of a nickel electrode and precipitation of nickel hydroxide in a completely intermixed electrolysis cell, wherein an electrolysis brine is used which has a content of 20 to 50 g/l of chloride ions and 1 to 7 g/l of ammonia with a pH value of 9.5 to 11.5 and a temperature of 45 to 60° C.

Abstract: The instant specification discloses a method for producing nickel hydroxide from an aqueous solution containing an ammonium ion and dissolved nickel hydroxide in an alkaline state, which is characterized in that pH of the solution is controlled by supplying a hydroxide ion generated by water electrolysis thereto. The method of the invention is an environmentally friendly one for producing nickel hydroxide, which enables an easy control of physical properties of nickel hydroxide.

Abstract: There are provided a method of and an apparatus for producing ultrafine metal compound particles. An electrolytic bath having an anode and a cathode is partitioned into chambers by at least one ion exchange layer. An electrolytic solution containing metal ions as a starting material for the ultrafine metal compound particles is contained in a chamber on the anodic side of one ion exchange layer, and an alkaline electrolytic solution is contained in a chamber on the cathodic side of the ion exchange layer. When a voltage is applied between the anode and the cathode, the metal ions transfer from the anodic side chamber to the cathodic side chamber through the ion exchange layer, whereby ultrafine metal compound particles are precipitated in the alkaline electrolytic solution in the cathodic side chamber.

Abstract: The present invention relates to processes for the production of cobalt(II) carbonates corresponding to the general formula Co[(OH)2]a[CO3]1−a, cobalt(II) carbonates and cobalt(II) oxalate carbonates obtainable by the process and the use thereof.

Abstract: The present invention is directed to a process for treating wastewater which comprises producing a ferric hydroxide suspension directly by electrolysis of the wastewater to precipitate heavy metals and organic or inorganic suspended solids thus purifying the wastewater. The purified wastewater, which is a saturated aqueous solution of calcium sulphate, can be recycled for further treatment and production of a low sulphate ferric hydroxide suspension. The process of the present invention is suitable for treatment of wastewaters obtained from mine tailings dams, metal mine pits, etc. and avoids the problems and difficulties of the known processes.

Abstract: A method of manufacturing conductive cobalt oxyhydroxide, including providing a positive electrode, a negative electrode, a CoOOH precursor, and a basic solution to form a combination; applying a current to the positive electrode to form conductive CoOOH on the positive electrode; then removing the conductive CoOOH from the combination, is disclosed.

Abstract: An non-sintered nickel electrode of alkaline batteries uses an active material powder which comprises composite particles comprising nickel hydroxide particles or solid solution particles consisting essentially of nickel hydroxide the surface of which is covered with a mixed crystal of cobalt hydroxide and the hydroxide of at least one metal (M) selected from the group consisting of aluminum, magnesium, indium and zinc. With this electrode, the cobalt hydroxide, which covers as a component of the mixed crystal the surface of the nickel hydroxide particles, minimally diffuses into them. Alkaline batteries using this electrode as positive electrode can therefore maintain, for a long period of time of charge-discharge cycles, the function of the cobalt hydroxide of increasing the conductivity of the electrode, thereby suppressing decrease in the discharge capacity in the course of charge-discharge cycles.

Abstract: A method is provided for removal of ferrous ions from a tin-plating electrolyte containing stannous ions in a multi-compartmented electrochemical cell equipped to convert the ferrous and stannous ions to insoluble hydroxides. The hydroxides, in an essentially air-oxygen free environment, are separated by selectively dissolving the ferrous hydroxide in an acidic solution and the undissolved stannous hydroxide in the tin plating electrolyte.

Abstract: The invention concerns an electrochemical process for the production of mllic hydroxides and/or metallic-oxide hydroxides from metal ions and hydroxide ions, as well as a device for carrying out the process. The metallic hydroxide and/or metallic-oxide hydroxide is formed in a chamber K, bordered on the cathode side by a bipolar membrane, and the required hydroxide ions arise by means of a bipolar membrane, the anion-selective layer being arranged on the anode side. The metal ions are either fed into the chamber K or formed in the chamber K in the presence of an agent, present in the chamber K and at a pH>7, which complexes the metal ions. The device for implementation of the process exhibits a cylindrical head geometry, connected to a conical geometry.

Abstract: The present invention relates to a process for the preparation of manganese(III)-containing nickel(II) hydroxide powders, more than 50 mole % of the manganese being present in the trivalent oxidation state, by co-precipitation of nickel(II) and manganese salt solutions with alkali liquors.

Abstract: A process for removing ferrous ions from a solution comprising the steps of: (a) introducing the solution into an electrolytic cell having an anode and a cathode, (b) electrolytically oxidizing ferrous ions in the presence of hydroxyl ions to produce ferric hydroxide, and (c) removing the solution from the cell, wherein liquid turbulence is induced at or in the proximity of, at least a portion of the surface of the anode whereby a mechanically stable, non-dendritic ferric hydroxide precipitate grows on or near the anode. Preferably, the ferrous ions are oxidized in the presence of chlorine. The chlorine may be electrolytically produced in the cell.

Abstract: Electrophoretic deposition (EPD) can be advantageously employed to uniformly coat or impregnate an array or preform of fibers with a ceramic material. As a result, more efficient methods for making composite materials of superior quality are provided.