Power is provided to an electrochemical cell. The electrochemical cell includes an anode side and a cathode side. Hydrogen sulfide in a liquid state is flowed to the anode side. Providing power to the electrochemical cell facilitates electrolysis of the hydrogen sulfide to produce sulfur and protons on the anode side. Providing power to the electrochemical cell facilitates reduction of protons to produce hydrogen on the cathode side. A membrane separating the anode side from the cathode side prevents flow of hydrogen sulfide and sulfur from passing through the membrane while allowing hydrogen cations to pass through the membrane. Sulfur is flowed out of the anode side. Hydrogen is flowed out of the cathode side.

A system and method for CO.sub.2 capture and electroregeneration and synchronous conversion are provided. The system includes a CO.sub.2 capture subsystem, which uses an absorption liquid to capture CO.sub.2 and generate a capture liquid; and a CO.sub.2 electroregeneration and synchronous conversion subsystem, including a cathode chamber provided with a cathode electrode, a sample inlet, and a sample outlet, an anode chamber having an anode electrode, a sample inlet connected to an outlet of the capture liquid of the CO.sub.2 capture subsystem, and a sample outlet connected to the sample inlet of the cathode chamber for introducing CO.sub.2 regenerated by anodic oxidation into the cathode chamber for electroreduction, and a balance chamber in the middle having a sample outlet connected to an inlet of the absorption liquid of the CO.sub.2 capture subsystem. The system can perform self-circulation and stably operate, to capture, regenerate and convert CO.sub.2.

A novel magnesium-based alloy is described. The alloy is particularly suitable for the construction of electrodes, especially anodes, that can be used for an electrochemical process, such as the synthesis of struvite. The magnesium-based alloy is an AZXY alloy in which A is aluminium and Z is zinc, X represents the content, expressed in wt. %, of the first element, and Y the content, expressed in wt. %, of the second element. The AZXY alloy according to the invention has 2%?X?4% and 0.5%?Y?2%, and an iron (Fe) content of less than 0.005%, and preferably less than 0.003%. The anodes constituted by this novel alloy have a much slower corrosion speed and improved performances compared to existing anodes. An electrode cartridge comprising said alloy and suitable for being inserted into an electrolytic reactor so as to form, once assembled, an electrocoagulation unit, is also described.

Methods and systems for producing are disclosed. A method for producing iron, for example, comprises: providing an iron-containing ore to a dissolution subsystem comprising a first electrochemical cell; wherein the first anolyte has a different composition than the first catholyte; dissolving at least a portion of the iron-containing ore using an acid to form an acidic iron-salt solution having dissolved first Fe.sup.3+ ions; providing at least a portion of the acidic iron-salt solution to the first cathodic chamber; first electrochemically reducing said first Fe.sup.3+ ions in the first catholyte to form Fe.sup.2+ ions; transferring the formed Fe.sup.2+ ions from the dissolution subsystem to an iron-plating subsystem having a second electrochemical cell; second electrochemically reducing a first portion of the transferred formed Fe.sup.2+ ions to Fe metal at a second cathode of the second electrochemical cell; and removing the Fe metal.

Methods and systems for producing iron from an iron-containing ore are disclosed. For example, a method for producing iron comprises: providing an iron-containing ore to a dissolution subsystem comprising a first electrochemical cell and a dissolution tank; dissolving the iron-containing ore to form an acidic iron-salt solution; reducing Fe.sup.3+ ions to form Fe.sup.2+ ions and electrochemically generating protons in the first electrochemical cell; circulating solution between the dissolution tank and the first electrochemical cell; transferring formed Fe.sup.2+ ions from the dissolution subsystem to an iron-plating subsystem having a second electrochemical cell; second electrochemically reducing a first portion of the transferred formed Fe.sup.2+ ions to Fe metal at a second cathode of the second electrochemical cell; and removing the Fe metal. The methods and systems optionally include removing one or more impurities found in the feedstock.

Methods and systems for dissolving an iron-containing ore are disclosed. For example, a method of processing and dissolving an iron-containing ore comprises: thermally reducing one or more non-magnetite iron oxide materials in the iron-containing ore to form magnetite in the presence of a reductant, thereby forming thermally-reduced ore; and dissolving at least a portion of the thermally-reduced ore using an acid to form an acidic iron-salt solution; wherein the acidic iron-salt solution comprises protons electrochemically generated in an electrochemical cell.

A method for recovering valuable metal elements from a copper-containing metallic material includes steps of: (a) immersing an anode and the copper-containing metallic material serving as a cathode into an electrolyte solution having one of an acidic pH and an alkaline pH; and (b) providing a predetermined voltage to the anode and the cathode such that an electrolysis process conducted under the predetermined voltage on the cathode forms a gaseous film surrounding the cathode, and then the gaseous film is broken down to permit generation of a plasma in the electrolyte solution so as to obtain a solid copper metal or a solid copper oxide that precipitates from the electrolyte solution, and ionic impurities that dissolve in the electrolyte solution.

A method for recovering valuable metal elements from a copper-containing metallic material includes steps of: (a) immersing an anode and the copper-containing metallic material serving as a cathode into an electrolyte solution having one of an acidic pH and an alkaline pH; and (b) providing a predetermined voltage to the anode and the cathode such that an electrolysis process conducted under the predetermined voltage on the cathode forms a gaseous film surrounding the cathode, and then the gaseous film is broken down to permit generation of a plasma in the electrolyte solution so as to obtain a solid copper metal or a solid copper oxide that precipitates from the electrolyte solution, and ionic impurities that dissolve in the electrolyte solution.

A method for preparing hydrogen sulfide from sulfur dioxide by electrochemical reduction includes electrochemically reducing sulfur dioxide absorbed in an aqueous solution into gaseous hydrogen sulfide with a membrane electrode, resulting in efficient and selective conversion of the sulfur dioxide absorbed in the aqueous solution into the hydrogen sulfide to avoid a deactivation of a cathode due to colloidal sulfur produced on the cathode and adhesion onto a surface of the cathode, wherein the method is carried out at ambient temperature and normal pressure without addition of a reducing agent, having no waste salts produced, and is simple in operation, and is convenient for large-scale application.

A method for preparing hydrogen sulfide from sulfur dioxide by electrochemical reduction includes electrochemically reducing sulfur dioxide absorbed in an aqueous solution into gaseous hydrogen sulfide with a membrane electrode, resulting in efficient and selective conversion of the sulfur dioxide absorbed in the aqueous solution into the hydrogen sulfide to avoid a deactivation of a cathode due to colloidal sulfur produced on the cathode and adhesion onto a surface of the cathode, wherein the method is carried out at ambient temperature and normal pressure without addition of a reducing agent, having no waste salts produced, and is simple in operation, and is convenient for large-scale application.