On the use of rotating electrodes in the measurement of the diffusion coefficient of aluminum fluoride in cryolitic melts

✍ Scribed by John W. Burgman; Paul J. Sides

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 846 KB
• Volume: 34
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(89)87117-8

✦ Synopsis

Discussed

is the use of rotating cylinder and disc electrodes to study mass transfer in cryolitic melts. In particular the effect of a thin liquid film at the surface of a rotating cylinder on the value of the dilIuslon coefficient deduced from the experiments is described. The thinness of the liquid aluminum film and the substantial interfacial tension of an aluminum-bath interface make the actual diffusion coeflicient lie within experimental error of the deduced diffusion coefficient. Also presented are a theoretical calculation of the current distribution on a rotating disc used in cryolitic melts and a calculation of the effect of a nonuniform current distribution on the measured apparent diffusivity. If the reference electrode is far from the edge of the disc, the apparent and actual diffusion coefficients measured in cryolitic melts are nearly equal.