Studies on the Hall-Heroult aluminum electrowinning process

Studies on the electrolysis of cryolite-alumina melt showed that even the b est equipped smelter, functioning at 960 degrees C, has only 33% energy eff iciency. For stable functioning of the smelter at 3% alumina the minimum wt % ratio NaF/AlF3 wa!; found to be 1.11. The anodes located on down-stream r ow were found to face more turbulence; raising their level by 4 cm resulted in decreasing the number of burnoffs. A careful selection of potlining mat erial improved the pot life. The stability of the aluminum-bath interface i s one of the major factors affecting the current efficiency. An improved ce ll design has been proposed to achieve the ultimate aluminum-bath interface stability. The proposed cell design should allow a reduction of the cathod e-to-anode distance producing a lower voltage and improving the power effic iency.