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.

The disclosure provides a method of producing hydrogen. The method comprises conducting a thermochemical reaction by contacting a metal, or an alloy thereof, with steam to produce a metal oxide and/or a metal hydroxide and hydrogen. The method then comprises contacting the metal oxide and/or the metal hydroxide produced in the thermochemical reaction with water or a basic aqueous solution to produce a solution comprising a metal ion. Finally, the method comprises conducting an electrochemical reaction by applying a voltage across an anode and a cathode, whereby at least a portion of the cathode contacts the solution comprising the metal ion, to produce hydrogen, oxygen and the metal, or the alloy thereof.

The disclosure provides a method of producing hydrogen. The method comprises conducting a thermochemical reaction by contacting a metal, or an alloy thereof, with steam to produce a metal oxide and/or a metal hydroxide and hydrogen. The method then comprises contacting the metal oxide and/or the metal hydroxide produced in the thermochemical reaction with water or a basic aqueous solution to produce a solution comprising a metal ion. Finally, the method comprises conducting an electrochemical reaction by applying a voltage across an anode and a cathode, whereby at least a portion of the cathode contacts the solution comprising the metal ion, to produce hydrogen, oxygen and the metal, or the alloy thereof.

Provided is a process and apparatus for reducing stannic oxide into metallic tin. The process includes: establishing at least one electrolytic cell; feeding the stannic oxide and an electrolyte solution into the at least one electrolytic cell, such that the stannic oxide directly contacts the cathode or the metallic tin on the cathode; initiating electrolysis, where at the anode, an electrochemical oxidation reaction occurs to dissolve a soluble anode metal or allow evolution of chlorine and/or oxygen at an insoluble anode, and at the cathode, the stannic oxide undergoes an electrochemical reduction reaction to produce the metallic tin; and collecting the metallic tin produced from the electrolysis and/or a solid product and/or a solution product of a tin compound produced from a reaction of the metallic tin with the electrolyte solution.

Provided is a process and apparatus for reducing stannic oxide into metallic tin. The process includes: establishing at least one electrolytic cell; feeding the stannic oxide and an electrolyte solution into the at least one electrolytic cell, such that the stannic oxide directly contacts the cathode or the metallic tin on the cathode; initiating electrolysis, where at the anode, an electrochemical oxidation reaction occurs to dissolve a soluble anode metal or allow evolution of chlorine and/or oxygen at an insoluble anode, and at the cathode, the stannic oxide undergoes an electrochemical reduction reaction to produce the metallic tin; and collecting the metallic tin produced from the electrolysis and/or a solid product and/or a solution product of a tin compound produced from a reaction of the metallic tin with the electrolyte solution.

A method for recovering a corrosion inhibitor from a water system includes treating a water stream of the water system that includes the corrosion inhibitor to selectively recover the corrosion inhibitor from the water stream. The method may include introducing the recovered corrosion inhibitor back into the water system. The corrosion inhibitor may be selectively recovered by applying a predetermined voltage to the electrochemical system to change an oxidation state of the corrosion inhibitor, the predetermined voltage corresponding to an oxidation reduction potential of the corrosion inhibitor.