Determination of ohmic/voltage drop and factors influencing anodic overvoltage of carbon anodes
in Na3AlF6-Al2O3 based melts
in Na3AlF6-Al2O3 based melts
(1. School of Metallurgical Science and Engineering,
Central South University, Changsha 410083, China
2. Chemistry Department, Guangxi Normal University, Guilin 5410043, China)
Central South University, Changsha 410083, China
2. Chemistry Department, Guangxi Normal University, Guilin 5410043, China)
Abstract: Experimental technique has been inadequate to anodic overvoltage measurements in aluminum electrolysis. To determine its ohmic/voltage drop precisely, a current interruption technique was modified with a high frequency digital oscilloscope, current interrupters with fast switching time, an improved cell configuration and a simulation applied to the oscillating potential decay curve. The results show that the technique can give good reproducibility for overvoltage studies. A substantial increase of anodic overvoltage is observed with graphite powder addition, metallic aluminum addition and CO bubbling in the melts.
Key words: ohmic/voltage drop; anodic overvoltage; aluminum electrolysis