Smelter savings

A barrier coating developed by researchers at the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) offers significant annual savings to aluminium smelters.

Smelter trials indicate that the low-cost coating prevents air burn oxidation and extends the operational life of carbon anodes used in high-temperature electrolytic cells.

Use of the coating was shown to produce a net reduction in carbon usage of 0.02kg carbon per kilogram of aluminium produced.

Dr Mahnaz Jahedi of CSIRO Materials Science and Engineering said: 'Our coating can provide considerable savings for the companies operating the more than 100 smelters that produce aluminium at present.'

Jahedi presented the results of the project at a recent meeting of The Minerals, Metals and Materials Society in San Francisco.

Carbon anodes are made from petroleum coke and, in the extreme heat of aluminium electrolysis cells, the exposed top and sides of the anodes can oxidise spontaneously owing to air burn.

Air burn can spread rapidly between anodes and necessitates more frequent interruptions to the smelting process to replace anodes.