Abstract: The invention relates to the production of multilayer electrodes on valve metal substrates, through a method comprising the application in alternate cycles of a solution containing precursors of noble metals, and of a second solution containing transition metals capable of forming protective coatings. The resulting electrodes are useful in several applications, among which copper and other metal plating and the treatment of waste or tap water.

Abstract: A method of producing an electrode by applying a solution of a non-stoichiometric compound of the formula Sn(OH)2+xCl2?x.nH2O followed by a thermal treatment and the electrodes produced by the said method.

Abstract: A method for the production of metallic copper in a substantially dendrite-free crystalline form is described, comprising an electrowinning from a cuprous and/or cupric chloride solution carried out in a spouted bed cell comprising a cathode consisting of a descending bed of metallic beads.

Abstract: A cell (100) for metal electrowinning from metal ion solutions is described, wherein the cathode (1) consists of a falling bed of growing beads; the beads, withdrawn from the lower part of the bed, are recycled to the top section of the cathodic compartment by means of an external vertical duct (3).

Abstract: A diaphragm electrolytic cell is composed of two or more overlaid modules; at least the upper modules having U-shaped anodes with diaphragm-coated cathodes housed within, allowing for a reduced electrode pitch.

Abstract: It is herein described an electrowinning cell with a spouted bed electrode of growing metallic beads, separated by a semi-permeable diaphragm and suitable for being assembled in a stack in a modular arrangement.

Abstract: The invention relates to an effluent COD treatment procedure by anodic oxidation combining the use of two different types of anode with a suitable apportionment of current. The first type of anode comprises an anode based on diamond doped-synthetic diamond. The second type of anode comprises an anode with high oxygen overvoltage containing tin and antimony oxides.

Abstract: It is described an electrolysis cell wherein the anodic dissolution of metals is carried out, in particular of metals characterised by a relatively high oxidation potential, such as copper, or metals with high hydrogen overpotential, for example tin, aimed at restoring both the concentration of said metals, and the pH in galvanic baths used in electroplating processes with insoluble anodes. The cell of the invention comprises an anodic compartment, wherein the metal to be dissolved acts as a consumable anode, and a cathodic compartment, containing a cathode for hydrogen evolution, separated by a cation-exchange membrane. The coupling of the cell of the invention with the electroplating cell allows a strong simplification of the overall process and a sensible reduction in the relevant costs.

Abstract: A cell (100) for metal electrowinning from metal ion solutions is described, wherein the cathode (1) consists of a falling bed of growing beads; the beads, withdrawn from the lower part of the bed, are recycled to the top section of the cathodic compartment by means of an external vertical duct (3).

Abstract: Object of the invention is an anodic structure for mercury cathode cells for the industrial electrolysis of sodium chloride. The new structure is constituted by a grid array comprising a multiplicity of vertically disposed and mutually parallel titanium blades, covered by an electrocatalytic coating specific for the discharge of chlorine. The ratio between the thickness and the height of the blades is comprised between 1:16 and 1:100 and the ratio between the surface of free passage between the blades and the projected surface is comprised between 15:17 and 25:30. The new grid array is perpendicularly fixed to new or existing frames having the function of mechanical support and current conduction to the grid array. Scope of the invention is simultaneously reducing the energetic consumption of the cell and the costs for restoring the exhausted electrocatalytic coating.

Abstract: The invention is relative to an electrolytic cell comprising electrodes spaced apart from the back-wall by means of ribs, wherein a portion of the contact surface between the electrodes and the ribs is free from constraints in order to permit the complete removal of the electrodes once they have to be replaced by removing only partially the original contact surface, so that positioning of the substitute electrodes is allowed on the residual portion. A method for substituting the electrodes of the cell which leaves the distance between the electrode surface and the back-wall unvaried is also disclosed.

Abstract: A noble metal sulfide catalyst obtained by reaction of a precursor of at least one noble metal with a thionic species in an aqueous environment essentially free of sulfide ions useful as an electrocatalyst in the depolarized electrolysis of hydrochloric acid.

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: The invention relates to an improved design of electrolyzer, in particular to the design of a diaphragm electrolyzer for the production of chlorine and alkali from aqueous solutions of alkali chlorides, comprising at least one anode fixed to an anodic base and in electrical contact therewith by means of a current collecting stem separated from the electrolyte circulating in the anodic compartment by means of a hydraulic seal system, wherein a conductive and deformable contact element is interposed between said current collecting stem and said anodic base, and wherein the hydraulic seal system comprises at least one O-ring.

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 characterised by a combination of micro-roughness and macro-roughness which favours 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 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 concerns a motorized device for adjusting the interelectrodic gap in mercury cathode electrolysis cells, mainly consisting of a frame, to which a number of anodes are suspended, movable in the vertical direction by means of a single jackscrew driven by a gear motor acting on double levers. The jackscrew with the motor and the lever system are fixed to a main frame, supported on the cell bottom by means of supports positioned on adjustable columns, while the above mentioned movable frame (also called sub-frame) carrying the anodes, is connected to the lever arms by means of four hinged supports. The shifting of the movable frame and, consequently, of the anodes can be controlled by a centralized and computerized system (which is not part of the invention) as a function of voltage and current variation measurements.

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.