Loading patent…
AssigneesSociete Des Electrodes, Refractaires Savoie (SERS)
InventorsGabriel Audras, Bernard Samanos
Estimating the term…
The invention concerns a coating for providing protection from corrosion and oxidation in the hot state, which coating is intended for the carrier bars of prebaked anodes and the emergent, or exposed, carbonaceous part of said anodes for Hall-Heroult electrolysis tanks, which elements are formed of a composition of carbonaceous aggregate selected from coke, graphite, semi-graphite and electrode scrap, together with calcium aluminate cement having an alumina content which is at least equal to 70% and a total amount of troublesome impurities (SiO.sub.2, Fe.sub.2 O.sub.3, TiO.sub.2, K.sub.2 O, Cr.sub.2 O.sub.3 and Mn.sub.2 O.sub.3) of less than 5% and preferably less than 2%. The protective coating may further comprise an addition of alumina powder in a proportion which can be up to 50% of the weight of the aggregate and an addition of 0.01% to 5% of metal powder such as passivated aluminium powder of a grain size of less than 0.1 mm. The coating may be used in the form of paste or be applied by spray gun.
A carbonaceous prebaked anode for the production of aluminum of high purity by the Hall-Heroult process, comprising a carrier iron bar, wherein at least a portion of said anode and a portion of said bar are coated with a composition consisting essentially of:
A coating composition for protecting from corrosion and oxidation in the hot condition carrier bars of prebaked anodes and the emergent carbonaceous part of said anodes for Hall-Heroult electrolysis tanks, consisting essentially of:
Dependencies are inferred from the claim text.