Electrolytic production of aluminium : fundamental and applied studies on the effect of anode composition on the anode-electrolyte interfacial conditions.

This thesis deals with a study of the wettability of amorphous carbon, of the type employed as anode material in the production of aluminium, by cryolite based solutions. The wettability of carbon has been improved by the addition of inorganic additives of the type used in cryolite electrolytes, such as aluminium oxide, calcium flanride and carbonate, and lithium flunride and carbonate. Particular improvements in carbon wettability are noted when the system is contained in an atmosphere of carbon dioxide - carbon monoxide, corresponding to practical production conditions. Furtheremore, when anodes prepared containing these additives are used in a laboratory aluminium cell, notable reductions in cell voltage are achieved at practical an0de current densities. The improved adhesion of the two phases has also been demonstrated by measurement of the current density and voltage conditions required to llinduce anode effects in this cell. Improvements in power requirements and carbon consumption per unit weight of product are shown, and finally, an assessment of the project potential under industrial operating conditions has been made.