ALUMINA REDUCTION CELL

Alumina reduction cells are used to prepare aluminium metal by the electrolytic reduction of alumina dissolved in molten cryolite. The molten aluminium formed collects at the bottom of the cell. When the cell floor serves as cathode and is of carbon, the molten aluminium does not wet the carbon making it necessary to increase the inter-electrode distance and reducing efficiency. The invention provides a cell wherein a floor cathode comprises a carbon substrate having an adherent surface layer of electrodeposited titanium diboride which is readily wettable by molten aluminium and which makes possible considerable savings in the expense of running the cell. The titanium diboride layer can be formed in situ in the cell or can be formed outside the cell on carbonaceous elements which are subsequently installed in the cell.