Effect of a Trace of Water and Solid LiF on Anode Effect in the KF 2 HF Melt

Abstract

The effect of a trace of water and solid in melt on anode effect has been investigated. When the melt contained a relatively large amount of water, anode effect was easily caused by the formation of graphite fluoride film on anode surface, independently of whether was present in the melt or not. The effect of solid suspended in the melt first appeared when the water content in the melt was decreased to less than 0.02% by pre‐electrolysis. Under this condition, it took much more time for anode effect to happen, even in the melt without , because the formation of graphite fluoride film was difficult and the electrochemical intercalation of in graphite occurred. When 3–6 weight percent (w/o) was added to this melt, anode effect did not occur, but fluorine intercalation was observed by the catalytic action of solid in addition to the electrochemical intercalation of .