System apparatus and process for leaching metal and storing thermal energy during metal extraction

Abstract

An environmentally friendly (e.g. no acid, base, or cyanide) system and process for large scale extraction of metal ion into aerobic molten salt (or ionic liquid) and the electrodeposition of metal (e.g. copper, gold, silver, etc.) from the metal ion dissolved in the molten salt. The non-volatile low vapor pressure liquid salt is reusable, and heat from the molten slag can heat the molten salts or ionic liquids. Another embodiment comprises a one-pot apparatus for the extraction of metal (e.g. copper) from metal earths and electrodepositing the metal using a low melting (209° C.) aerated Na—K—Zn chloride salt in which copper metal oxidizes and is converted to soluble copper chloride. When an electrical power supply is connected to the graphite vessel (cathode) and to copper rods in the melt (anodes), then the copper chloride is deposited as copper metal by electroreduction on the bottom of the graphite reaction vessel.