Methods and systems for use in targeted removal of metals from a substrate via electrorefining are described. A self-propagating reaction is initiated by use of a thermite to reach high temperatures sufficient to induce localized melting of a salt situated on a metal or alloy substrate. Using a power supply connected to an electrode assembly, an electrorefining reaction capable of generating significant localized corrosion of the substrate is produced.

Systems and methods for recovery of gaseous substances from molten salt electrolysis are generally described. Certain systems comprise a cell configured for molten salt electrolysis; a collector fluidically connected to the cell and configured to collect volatilized molten salt from the cell; and a gas scrubber fluidically connected to the collector and configured to at least partially remove a gas from an effluent stream of the cell. Some methods comprise, using a pressure gradient: transporting a gas comprising molten salt vapor from an electrolytic cell to and through a collector such that at least a portion of the molten salt vapor forms a solid within the collector; and transporting some or all of the gas from the collector through a gas scrubber.