Laminated carbon cathode for cells for the production of aluminium by electrolytic smelting

摘要

Laminated carbon cathode constisting of two layers of carbon blocks; the upper layer (1) being of graphite of graphitized carbon, whilst the lower layer (2) consists of a cheaper anthracite carbon. The two layers are so displaced with respect to each other that there are no vertical seams (7) leading straight from the upper side of the carbon cathode to its underside. Dividing the cathode into two horizontal layers is combined with the embedding of current-carrying steel conductors (4) in precise grooves between the layers. In order to capitalize on the good electrical conductivity of aluminium, an aluminium extension (10) is friction-welded to each steel conductor as close to the cell as possible, whilst at the same time a collar (9) is formed which provides an air-tight seal at the point where the cathode bar enters the side of the shell. The proposed arrangement facilitates a very practical and simple check on dimensional deviations in the carbon blocks/cathode bars, and of fitting accuracy, by the visual inspection of seam tolerances and the displacement of axes during the lining operation.