High-temperature NMR study of Al dissolution in cryolitic melts

The dissolution of aluminium in cryolitic melts is the major cause of the loss in current efficiency during the industrial process of aluminium electrolysis. These melts are corrosive and not easy to handle experimentally. Using the laser-heated device, associated with a tightly closed crucible, we have studied different compositions of the NaF-AIF(3)-Al system by Al-27, Na-23 and F-19 in situ NMR at 1030 degreesC. The samples were also characterized after rapid cooling at room temperature by MAS NMR, X-rays diffraction and microscopy in order to describe the structure of the solidified phases. (C) 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.