Abstract:
The production of primary aluminium in January 2016 was 4726000 tons, corresponding to about 57 million tons a year. The latest expansions have been in the Middle East and above all in China which now is responsible for 52% of the world production. The newest smelters are either high amperage, +600 kamp or low energy, less than 11 kWh/kg Al. The used cathode materials are getting more graphitic and SiC sidewalls are used extensively. Strong shells are needed, while the refractory and insulation materials remain the same. The off gas of fluorides to air is very satisfactory, less than 0,2 kg F/tAl, but spent potlining is still a problem. Only amperage and voltage can be measured continuously, but proprietary computer programs have led to very good management of the cell technology. No radical innovations are in sight, but the following actions which will be discussed are promising: The Chinese protruding cathodes, use of slotted anodes, flow adapted feeding, 25% increase of amperage within the same shell, use of copper collector bars, improved analytic sensors as the Alcoa and Heraeus probes. No new demonstrations of inert cathodes or anodes have been reported.
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