IMPROVING THE BAYER PROCESS BY POWER ULTRASOUND INDUCED CRYSTALLIZATION (SONOCRYSTALLIZATION) OF KEY IMPURITIES
Ruecroft, G., Hipkiss, D., Ly, T. and Fennell, M.
The Bayer process, used worldwide to produce alumina from bauxite, is a precursor to aluminium and many other high value products but productivity can be hampered by dissolved organic impurities in the process liquor. Sonocrystallization technology [utilizing large-scale power ultrasonic devices to aid crystallization] has been shown to have significant beneficial effects on the removal of the key impurity sodium oxalate from the caustic process stream by crystallization. Favourable results have been seen in laboratory experiments, pilot trials carried out over a 6-month period and more recently in full-scale trials. Overall benefits include increased alumina productivity, reduced sodium hydroxide consumption, caustic liquor disposal, operating cost and energy consumption with concomitant reduced environmental burden.