HARD AND ABRASION RESISTANT SURFACES PROTECTING CATHODE BLOCKS OF ALUMINIUM ELECTROWINNING CELLS

摘要

A cathode block of a cell for the electrowinning of aluminium comprises a carbon body having a hard and abrasion-resistant surface obtained by heating an applied layer of particulate refractory hard metal boride with a bonding material which when heated reacts with the refractory hard metal boride and with carbon. In particular a slurry of particulate refractory boride in colloidal alumina is dried and heated under an inert or a reducing atmosphere, formed by a bed of carbon powder, and reacted to form at least one stable compound between aluminium derived from colloidal alumina; boron and titanium derived from the titanium diboride; and carbon from the reducing atmosphere.