Abstract: A process for recovering gold from a refractory gold ore, comprising the steps of: electrolyzing a mixture consisting of the ore particles and an aqueous bromide solution in an electrolytic cell having anode and cathode, wherein bromine is produced at the anode by oxidation of the bromide, thereby dissolving gold in the aqueous phase; separating the ore particles from the aqueous phase to obtain a leach liquor; adjusting the pH of the leach liquor to the alkaline range to produce a gold-containing precipitate; collecting the gold-containing precipitate and recycling a bromide-containing barren solution for reuse as an aqueous bromide feed solution.

Abstract: Electrocatalyst, electrode coating and an electrode for preparing chlorine and process for producing the electrode, the electrocatalyst comprising a noble metal oxide and/or a noble metal of transition groups VIIIa of the Periodic Table of the Elements and at least one finely divided pulverulent oxide of another metal, in which one or more components are doped and the base metal oxide powder is chemically stable in the presence of aqueous electrolytes.

Abstract: A process for wet-chemical production of a catalyst coating on an electrically conductive support for electrodes for chloralkali or hydrochloric acid electrolysis with electrocatalytically active components based on noble metal oxides, in which the catalyst coating is produced by; producing a coating solution or dispersion comprising a precursor compound of a noble metal and/or a metal oxide of a noble metal, and a solvent or dispersant, with addition of one or more acids to the coating solution or dispersion, where the molar ratio of the total of the amounts of acid (in mol) present in the coating solution or dispersion to the sum of the amounts of the metals from the metal-containing components present in the coating solution or dispersion is at least 2:1; applying the coating solution or dispersion to the support; substantially freeing the layer applied of solvent or dispersant by drying; and subjecting the dried layer obtained to a thermal treatment to form the catalyst coating.

Abstract: A highly stable aqueous solution having a molecular cluster with dimensions which are small enough to ensure substantial chemical-physical stability thereof for a relatively long time. To prepare the solution a fluid treatment device is used, which comprises at least one chamber (7) and at least one anode (4) and one cathode (3) arranged in the chamber (7). The anode (4) and cathode (3) are at least partly made of a first metallic material. At least one of the at least one cathode (3) and anode (4) comprises a coating of nanoparticles (5) of a second metallic material.

Abstract: The present invention claims a method for forming [18F] fluoride complexes suitable for performing radio-labelling reactions to generate [18F] fluorinated species. The present invention also provides for an apparatus for forming [18F] fluoride complexes suitable for performing radio-labelling reactions to generate [18F] fluorinated species. Kit claims for formation of [18F] fluoride complexes suitable for performing radio-labelling reactions to generate [18F] fluorinated species are also provided.

Abstract: Methods for the reductive post-treatment of NaCl-containing solutions, wherein such methods comprise: providing a NaCl-containing solution obtained from an anode side of an NaCl electrolysis cell, the solution comprising reducible components; and subjecting the solution to cathodic electrochemical reduction.

Abstract: The present invention relates to an electrode comprising an electrically conductive substrate and a catalytically active layer, wherein the catalytically active layer is based on two catalytically active components and comprises iridium, ruthenium or titanium as metal oxide or mixed oxide or mixtures of the oxides, wherein the total content of ruthenium and/or iridium based on the sum of the elements iridium, ruthenium and titanium is at least 10 mol %, and wherein the electrode comprises at least one oxidic base layer which is applied to the electrically conductive substrate and is impermeable to aqueous electrolytes comprising NaCl and/or NaOH and/or HCl.

Abstract: An oxygen-depolarized cathode for aqueous hydrochloric acid electrolysis membrane cells is described, the cathode being in contact with the membrane and capable of preventing the release of hydrogen into oxygen even at the highest current densities. Hydrochloric acid may also be of technical grade with a concentration limited to 15%, whereas the operating temperature must not exceed 60° C. The cathode contains a mixture of rhodium sulphide and a metal of the platinum group applied in a single layer or alternatively applied separately in two distinct layers.

Abstract: A rhodium sulfide electrocatalyst formed by heating an aqueous solution of rhodium salt until a steady state distribution of isomers is obtained and then sparging hydrogen sulfide into the solution to form the rhodium sulfide and a membrane electrode assembly with the said electrode and a process for electrolyzing hydrochloric acid.

Abstract: An oxygen-depolarised cathode for aqueous hydrchloric acid electrolysis membrane cells is described, the cathode being in contact with the membrane and capable of preventing the release of hydrogen into oxygen even at the highest current densities. Hydrochloric acid may also be of technical grade with a concentration limited to 15%, whereas the operating temperature must not exceed 60° C. The cathode contains a mixture of rhodium sulphide and a metal of the platinum group applied in a single layer or alternatively applied separately in two distinct layers.

Abstract: In a method and an apparatus for generating a portable sterilizing water that can be easily used at, for example, hospitals, cafeterias of nursing facilities, restaurants, hair salons or homes, an electrolyzer is structured such that a tubular-shaped ferrite anode and a cathode are arranged alternately in a concentric manner with an inter-electrode distance, and integrated with a pressurizable solution container containing halogen ions and a power control apparatus so that it can be carried and operated by one hand.

Abstract: A process for electrolyzing an aqueous solution of hydrochloric acid to chlorine in an electrochemical cell provided with an anode compartment and a cathode compartment including at least one gas diffusion cathode comprising an electrically conductive web provided on at least one side thereof with a coating of a catalyst for the electroreduction of oxygen comprising rhodium sulfide and optionally containing at least one fluorinated binder incorporated therein, comprising introducing aqueous hydrochloric acid containing contaminant species into the anode compartment and oxygen into the cathode compartment while impressing a direct electric current on the cell.

Abstract: The invention is relative to an electrode for gas evolution in electrolytic and electrometallurgical industrial applications, made of a metal substrate having a surface morphology characterized by a combination of micro-roughness and macro-roughness which favors high adherence of a superficial catalytic layer in order to prevent detachment of the same and passivation of the substrate even under critical operating conditions.

Abstract: The invention relates to a novel rhodium sulfide catalyst for the reduction of oxygen in industrial electrolyzers. The catalyst is highly resistant towards corrosion and poisoning by organic species, thus resulting particularly suitable for use in aqueous hydrochloric acid electrolysis, when technical grade acid containing organic contaminants is employed.

Abstract: In removal of sulfate groups and chlorate groups from brine used for electrolysis, concentrated brine used in an electrolysis process or dilute brine whose concentration is decreased by electrolysis is fed to an anode chamber divided by a cation exchange membrane in a brine treating electrolyzer, where the concentrated or dilute brine is electrolyzed to recover chloride ions therein. The concentrated brine is electrolyzed at a rate of decomposition of salt higher than that in the ion exchange membrane electrolysis process of brine. Thereafter, the concentrated or dilute brine is discharged out of the electrolysis process.

Abstract: A new electrocatalytic coating to be applied onto a titanium matrix, suitable for oxygen evolution from acid electrolytes containing manganese and fluorides, comprising:a) an external coating for oxygen evolution at controlled potential, immune to manganese electrochemical precipitation and capable of promoting the spontaneous removal of the same during operation, consisting of ruthenium and iridium as the major components (60-85%), tin and cobalt (2-10%) and titanium and tantalum at intermediate concentrations with respect to the previous groups of components.b) an optional interlayer acting as an electroconductive system and protecting the titanium matrix against corrosion caused by fluorides, made of titanium and tantalum as the major components (<95%) and iridium (>5%) as the minor component.At least part of the above elements are in the form of oxides.

Abstract: A reactivation method for an electrolyzer for the production of sodium hydrochlorite and chlorate, equipped with interleaved plates acting as anodes and cathodes, wherein at least the anode plates are provided with foraminous sheets having an electrocatalytic coating and a planar profile, said sheets being applied to the anode plates by means of a multiplicity of connection points.

Abstract: A gas diffusion electrode comprising an electrically conductive web provided on at least one side thereof with a coating containing a rhodium--rhodium oxide catalyst on a carbon black support and a method for the preparation of the rhodium--rhodium oxide catalyst.

Abstract: A process for leaching gold, silver, platinum and palladium wherein an aqueous leaching solution containing bromine and bromide ion contacts a precious metal source to produce an aqueous leachate. A precursor composition for producing an aqueous leaching solution for leaching gold, silver, platinum and palladium. A process for electrogenerating bromine and a process for leaching gold, silver, platinum and palladium wherein bromine is electrogenerated and contacts a precious metal source to produce an aqueous leachate. A process for leaching gold, silver, platinum and palladium wherein bromine is electrogenerated from a solution containing chloride ions and bromide ions.