Initial 1000A Aluminum Electrolysis Testing in Potassium Cryolite‐Based Electrolyte

Aluminum electrolysis testing in a 1000A cell at 750°C is described. The cell was fitted with 3 vertically oriented aluminum-bronze anodes and 3 wetted cathodes, maintaining an anode-to-cathode distance of 2.2 cm. The electrodes were immersed in a KF-AlF3 electrolyte with a cryolite ratio of 1.3. Alumina was automatically fed to the cell to maintain a dissolved alumina concentration of 5 wt%, confirmed by analysis. Boron nitride was used as the cell liner material. During electrolysis, the voltage was stable near 4.0 volts at a current density of 0.5 A/cm2. Oxygen gas evolved from the cell was measured with an oxygen sensor. During the 24-hour initial electrolysis test, the anodes were protected by a dense oxide layer.