The application is directed towards methods for purifying an aluminum feedstock material. A method provides: (a) feeding an aluminum feedstock into a cell (b) directing an electric current into an anode through an electrolyte and into a cathode, wherein the anode comprises an elongate vertical anode, and wherein the cathode comprises an elongate vertical cathode, wherein the anode and cathode are configured to extend into the electrolyte zone, such that within the electrolyte zone the anode and cathode are configured with an anode-cathode overlap and an anode-cathode distance; and producing some purified aluminum product from the aluminum feedstock.