The process and the apparatus described hereinbefore are applied to the series of tanks intended for the production of {HEAD ~ aluminium} by {TAIL ~ the electrolysis} of alumina dissolved in molten cryolite base baths and more particularly to the situation where the bath comprises: 
The process and the apparatus described hereinbefore are applied to the series of tanks intended for the production of { HEAD ~ aluminium } by { TAIL ~ the electrolysis } of alumina dissolved in molten cryolite base baths and more particularly to the situation where the bath comprises :
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