Patent ID: 8460535

Claim:
A method of electrowinning an element from a compound, comprising: providing a liquid electrolyte in which the compound is dissolved; providing a first cathode in electrical contact with the electrolyte; providing an anode in electrical contact with the electrolyte; extracting electrons from the anode while providing electrons to the first cathode, thereby depositing a solid material including an impurity from the electrolyte onto the first cathode, thereby depleting the electrolyte of the impurity; stopping deposition onto the first cathode; providing a second cathode in electrical contact with the electrolyte; and after stopping deposition onto the first cathode, extracting electrons from the anode while providing electrons to the second cathode, thereby depositing a solid product, at least 99% of which is the element, from the depleted electrolyte onto the second cathode, wherein, during deposition of the solid product onto the second cathode, a membrane interposed between the anode and the electrolyte conveys anions from the electrolyte to the anode and further comprising electrically isolating the anode while extracting electrons from the second cathode while providing electrons to a counter cathode in contact with the liquid electrolyte, thereby electrodissolving a portion of the deposited solid product from the second cathode and plating solid material comprising the element onto the counter cathode.