The recovery of gold and/or silver from gold and/or silver containing material is generally described. The gold and/or silver can be recovered selectively, in some cases, such that gold and/or silver are at least partially separated from non-silver and/or non-gold material. Gold and/or silver may be recovered from material using mixtures of acids, in some instances. In some cases, the mixture can comprise nitric acid and at least one supplemental acid, such as sulfuric acid or phosphoric acid. The amount of nitric acid within the mixture can be, in some instances, relatively small compared to the amount of sulfuric acid or phosphoric acid within the mixture. In some cases, the recovery of gold and/or silver using the acid mixtures can be enhanced by transporting an electric current between an electrode and the gold and/or silver of the material. In some cases, acid mixtures can be used to recover silver from particular types of materials, such as material comprising silver metal and cadmium oxide and/or material comprising silver metal and tungsten metal.

The recovery of gold and/or silver from gold and/or silver containing material is generally described. The gold and/or silver can be recovered selectively, in some cases, such that gold and/or silver are at least partially separated from non-silver and/or non-gold material. Gold and/or silver may be recovered from material using mixtures of acids, in some instances. In some cases, the mixture can comprise nitric acid and at least one supplemental acid, such as sulfuric acid or phosphoric acid. The amount of nitric acid within the mixture can be, in some instances, relatively small compared to the amount of sulfuric acid or phosphoric acid within the mixture. In some cases, the recovery of gold and/or silver using the acid mixtures can be enhanced by transporting an electric current between an electrode and the gold and/or silver of the material. In some cases, acid mixtures can be used to recover silver from particular types of materials, such as material comprising silver metal and cadmium oxide and/or material comprising silver metal and tungsten metal.

Systems and methods for the recovery of noble metal from noble-metal-containing material are generally described. Certain embodiments related to systems and methods in which an electric current is transported between an electrode and the noble metal of a noble-metal-containing material to dissolve at least a portion of the noble metal from the noble-metal-containing material. The dissolved noble metal can subsequently be precipitated out of solution and recovered, according to certain embodiments. Noble metals can be recovered from any suitable noble-metal-containing material, including plated and/or filled scrap materials and/or other materials.

Systems and methods for the recovery of noble metal from noble-metal-containing material are generally described. Certain embodiments related to systems and methods in which an electric current is transported between an electrode and the noble metal of a noble-metal-containing material to dissolve at least a portion of the noble metal from the noble-metal-containing material. The dissolved noble metal can subsequently be precipitated out of solution and recovered, according to certain embodiments. Noble metals can be recovered from any suitable noble-metal-containing material, including plated and/or filled scrap materials and/or other materials.

The invention generally relates to systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions. In certain aspects, the invention provides methods that involve providing a metal and a solvent. The methods additionally involve applying voltage to the solvated metal to thereby produce solvent droplets including ions of the metal containing compound, and directing the solvent droplets including the metal ions to a target. In certain embodiments, once at the target, the metal ions can react directly or catalyze reactions.

The invention generally relates to systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions. In certain aspects, the invention provides methods that involve providing a metal and a solvent. The methods additionally involve applying voltage to the solvated metal to thereby produce solvent droplets including ions of the metal containing compound, and directing the solvent droplets including the metal ions to a target. In certain embodiments, once at the target, the metal ions can react directly or catalyze reactions.

A dielectric barrier discharge (DBD) plasma apparatus for synthesizing metal particles is provided. The DBD plasma apparatus includes an electrolyte vessel for receiving an electrolyte solution comprising metal ions; an electrode spaced-apart from the electrolyte vessel; a dielectric barrier interposed between the electrolyte vessel and the electrode such that, when the electrolyte solution is present in the electrolyte vessel, the dielectric barrier and an upper surface of the electrolyte solution are spaced-apart from each other and define a discharge area therebetween; and gas inlet and outlet ports in fluid communication with the discharge area such that supplying gas in the discharge area while applying an electrical potential difference between the electrode and the electrolyte solution cause a plasma to be produced onto the electrolyte solution, the plasma interacting with the metal ions and synthesizing metal particles. A method for synthesizing metal particles using a DBD plasma apparatus is also provided.

A dielectric barrier discharge (DBD) plasma apparatus for synthesizing metal particles is provided. The DBD plasma apparatus includes an electrolyte vessel for receiving an electrolyte solution comprising metal ions; an electrode spaced-apart from the electrolyte vessel; a dielectric barrier interposed between the electrolyte vessel and the electrode such that, when the electrolyte solution is present in the electrolyte vessel, the dielectric barrier and an upper surface of the electrolyte solution are spaced-apart from each other and define a discharge area therebetween; and gas inlet and outlet ports in fluid communication with the discharge area such that supplying gas in the discharge area while applying an electrical potential difference between the electrode and the electrolyte solution cause a plasma to be produced onto the electrolyte solution, the plasma interacting with the metal ions and synthesizing metal particles. A method for synthesizing metal particles using a DBD plasma apparatus is also provided.

A method of recovering metals from electronic waste comprises providing a powder comprising electronic waste in at least a first reactor and a second reactor and providing an electrolyte comprising at least ferric ions in an electrochemical cell in fluid communication with the first reactor and the second reactor. The method further includes contacting the powders within the first reactor and the second reactor with the electrolyte to dissolve at least one base metal from each reactor into the electrolyte and reduce at least some of the ferric ions to ferrous ions. The ferrous ions are oxidized at an anode of the electrochemical cell to regenerate the ferric ions. The powder within the second reactor comprises a higher weight percent of the at least one base metal than the powder in the first reactor. Additional methods of recovering metals from electronic waste are also described, as well as an apparatus of recovering metals from electronic waste.

A method of recovering metals from electronic waste comprises providing a powder comprising electronic waste in at least a first reactor and a second reactor and providing an electrolyte comprising at least ferric ions in an electrochemical cell in fluid communication with the first reactor and the second reactor. The method further includes contacting the powders within the first reactor and the second reactor with the electrolyte to dissolve at least one base metal from each reactor into the electrolyte and reduce at least some of the ferric ions to ferrous ions. The ferrous ions are oxidized at an anode of the electrochemical cell to regenerate the ferric ions. The powder within the second reactor comprises a higher weight percent of the at least one base metal than the powder in the first reactor. Additional methods of recovering metals from electronic waste are also described, as well as an apparatus of recovering metals from electronic waste.