The initiation, propagation and termination of anode effects in Hall-Héroult cells

Abstract

Anode effects in Hall-Héroult cells have been the subject of multiple investigations and studies. The current state of the knowledge is fairly well advanced and there is very little discrepancy or controversy with respect to many of the phenomena associated with anode effects. Included in this is the belief they are: 1) AE are the predominate emitter of PFC into the atmosphere 2) AE are triggered by low alumina concentrations near the anode surface 3) Short circuiting of at least part of the anode cathode inter electrode gap is required to terminate an anode effect. This paper will cover some of less discussed aspects of anode effect including: 1) the initiation at a single random anode in the circuit; 2) propagation to multiple anodes until the whole circuit is on anode effect and; 3) reason it is necessary to short circuit the anodes to terminate anode effect.