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Pre-heating of alumina. Weight of rafts at different temperatures

Pre-heating of alumina. Weight of rafts at different temperatures

Kategori
Rapport
Sammendrag
It has been suggested that the alumina added to aluminium electrolysis cells should be pre-heated to obtain more rapid dissolution and thereby smoother operation. To investigate the effect of pre-heating, the formation of alumina "rafts" upon feeding a batch of alumina to the surface of molten cryolitic bath was studied in the laboratory. The alumina batches were heated to pre-determined temperatures, and the rafts formed were collected by means of a plate-shaped sampler. It turned out that coherent rafts were formed up to at least 500 °C. Since alumina dissolution is mass transfer controlled, this means that preheating the alumina will have no effect on its dissolution rate until the temperature is at least 500 °C. Preheating to such temperatures represents a great challenge in industrial cells.
Oppdragsgiver
  • Research Council of Norway (RCN) / 257632
Språk
Engelsk
Forfatter(e)
Institusjon(er)
  • SINTEF Industri / Metallproduksjon og prosessering
År
2019
Forlag
SINTEF Industry