Abstract
By means of existing theory for mass and heat transfer to spherical particles the dissolution time for individual alumina grains dispersed in cryolite melts was calculated to be of the order of 10 s, in agreement with experiments. Heat transfer is limiting during heat-up but not during dissolution. Under normal conditions alumina powder agglomerates when being fed to the melt, and lumps are formed which dissolve much more slowly (minutes, hours). An electroanalytical technique was used to monitor the alumina concentration in the bath, and dissolution rates were determined for alumina being fed to the bath as well as for alumina resting at the bottom and for rotating alumina discs. The results were fitted to models for mass transfer controlled reactions.
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Thonstad, J., Solheim, A., Rolseth, S., Skar, O. (2016). The Dissolution of Alumina in Cryolite Melts. In: Bearne, G., Dupuis, M., Tarcy, G. (eds) Essential Readings in Light Metals. Springer, Cham. https://doi.org/10.1007/978-3-319-48156-2_14
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DOI: https://doi.org/10.1007/978-3-319-48156-2_14
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