A method for producing metallic silver by electro-deposition, including electrolyzing an electrolyte solution containing Ce(NO.sub.3).sub.3 in an anode zone and an electrolyte solution containing AgNO.sub.3 in a cathode zone by using an electrolytic cell with a specific diaphragm, wherein the electrolyte solution in the anode zone is not allowed to enter the cathode zone. After the electrolyzing is complete, the metallic silver with a high purity is obtained at the cathode, and a Ce.sup.4+-containing solution is obtained in the anode zone.

Disclosed are an electrolytic reduction system of a vanadium electrolyte and a method for producing the electrolyte. The electrolytic reduction system includes a separating device and an electrolytic tank. The separating device is configured to separate a mixture consisting of a vanadium pentoxide (V2O5) solid and a sulfate acid solution, thereby obtaining a vanadium solution from a liquid discharging port of the separating device and a vanadium solid from a solid discharging port. The vanadium solution includes pentavalent vanadium ions. The electrolytic tank connects to the liquid discharging port of the separating device to contain the vanadium solution. In the method for producing the vanadium electrolyte, other chemical reagents are unnecessarily to be added into the mixture, and the vanadium solution is subjected to an electrolytic reduction process, such that the pentavalent vanadium ions are reduced to tetravalent vanadium ions and trivalent vanadium ions in the electrolytic tank.

Disclosed are an electrolytic reduction system of a vanadium electrolyte and a method for producing the electrolyte. The electrolytic reduction system includes a separating device and an electrolytic tank. The separating device is configured to separate a mixture consisting of a vanadium pentoxide (V2O5) solid and a sulfate acid solution, thereby obtaining a vanadium solution from a liquid discharging port of the separating device and a vanadium solid from a solid discharging port. The vanadium solution includes pentavalent vanadium ions. The electrolytic tank connects to the liquid discharging port of the separating device to contain the vanadium solution. In the method for producing the vanadium electrolyte, other chemical reagents are unnecessarily to be added into the mixture, and the vanadium solution is subjected to an electrolytic reduction process, such that the pentavalent vanadium ions are reduced to tetravalent vanadium ions and trivalent vanadium ions in the electrolytic tank.

A method for cleanly extracting metallic silver includes: mixing an acidic solution containing Ce.sup.4+ and NO.sub.3.sup.− with a silver-containing material for leaching; after the leaching is completed, carrying out a solid-liquid separation to obtain a leaching solution containing Ce.sup.3+ and Ag.sup.+; and electrolyzing the leaching solution, wherein an oxidation reaction of Ce′ occurs at an anode to realize a regeneration of Ce.sup.4+ and an electrolytic reduction occurs at a cathode to reduce Ag.sup.+ to obtain the metallic silver. Ce.sup.4+ is used as a leaching agent and an intermediate oxidant to implement a cyclic operation of solution leaching and electrolytic regeneration on the silver-containing material. Almost no NO.sub.x and waste liquid are caused by the extraction process, and the invention is clean and environmentally friendly.

A method for cleanly extracting metallic silver includes: mixing an acidic solution containing Ce.sup.4+ and NO.sub.3.sup.− with a silver-containing material for leaching; after the leaching is completed, carrying out a solid-liquid separation to obtain a leaching solution containing Ce.sup.3+ and Ag.sup.+; and electrolyzing the leaching solution, wherein an oxidation reaction of Ce′ occurs at an anode to realize a regeneration of Ce.sup.4+ and an electrolytic reduction occurs at a cathode to reduce Ag.sup.+ to obtain the metallic silver. Ce.sup.4+ is used as a leaching agent and an intermediate oxidant to implement a cyclic operation of solution leaching and electrolytic regeneration on the silver-containing material. Almost no NO.sub.x and waste liquid are caused by the extraction process, and the invention is clean and environmentally friendly.

A system to remove sodium and Sulfur from a feed stream containing alkali metal sulfides and polysulfides in addition to heavy metals. The system includes an electrolytic cell having an anolyte compartment housing an anode in contact with an anolyte. The anolyte includes alkali metal sulfides and polysulfides dissolved in a polar organic solvent. The anolyte includes heavy metal ions. A separator includes an ion conducting membrane and separates the anolyte compartment from a catholyte compartment that includes a cathode in contact with a catholyte. The catholyte includes an alkali ion-conductive liquid. A power source applies a voltage to the electrolytic cell high enough to reduce the alkali metal and oxidize Sulfur ions to allow recovery of the alkali metal and elemental sulfur. The ratio of sodium to Sulfur is such that the open circuit potential of the electrolytic cell is greater than about 2.3V.

A system to remove sodium and Sulfur from a feed stream containing alkali metal sulfides and polysulfides in addition to heavy metals. The system includes an electrolytic cell having an anolyte compartment housing an anode in contact with an anolyte. The anolyte includes alkali metal sulfides and polysulfides dissolved in a polar organic solvent. The anolyte includes heavy metal ions. A separator includes an ion conducting membrane and separates the anolyte compartment from a catholyte compartment that includes a cathode in contact with a catholyte. The catholyte includes an alkali ion-conductive liquid. A power source applies a voltage to the electrolytic cell high enough to reduce the alkali metal and oxidize Sulfur ions to allow recovery of the alkali metal and elemental sulfur. The ratio of sodium to Sulfur is such that the open circuit potential of the electrolytic cell is greater than about 2.3V.

Devices and methods for purifying lithium from lithium salts, including those with low concentration of lithium salts, are provided. A molten composition comprising a lithium salt is electrolyzed with an anode in contact with the molten composition and a cathode separated from the molten composition by a solid electrolyte capable of conducting lithium ions.

Devices and methods for purifying lithium from lithium salts, including those with low concentration of lithium salts, are provided. A molten composition comprising a lithium salt is electrolyzed with an anode in contact with the molten composition and a cathode separated from the molten composition by a solid electrolyte capable of conducting lithium ions.

A lithium metal electrode has no more than five ppm of non-metallic elements by mass, and is bonded to a conductive substrate. Optionally, the lithium metal electrode may be bonded on one side to a conductive substrate and on another side to a lithium ion selective membrane. The lithium metal electrode may be integrated into lithium metal batteries. The inventive lithium metal electrode may be manufactured by a process involving electrolysis of lithium ions from an aqueous lithium salt solution through an ion selective membrane, carried out under a blanketing atmosphere having no more than 10 ppm of non-metallic elements, the electrolysis being performed at a constant current between about 10 mA/cm.sup.2 and about 50 mA/cm.sup.2, and wherein the constant current is applied for a time between about 1 minute and about 60 minutes.