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The effect of 20 kHz ultrasound on alumina hydrate precipitation from seeded sodium aluminate solution was studied. Compared with alumina hydrate precipitation without treatment of ultrasound, the precipitation time is reduced from 30 h to 15 h when the precipitation ratio is 45% under 20 kHz ultrasound. Furthermore, agglomeration is increased and the growth rate of alumina hydrate is increased under 20 kHz ultrasound by comparing the crystal size distribution and the SEM photographs. As a result, the average size of alumina hydrate is increased by 3.7 μm. The structure of product is not changed according to the results of X ray powder deflection.
Compared to alumina hydrate precipitation without treatment of ultrasound, the precipitation time is reduced from 30 h to 15 h when the precipitation ratio is 45% under 20 kHz ultrasound ., Agglomeration is increased and the growth rate of alumina hydrate is increased under 20 kHz ultrasound by comparing the crystal size distribution and the SEM photograph. As a result, the average size of alumina hydrate is increased by 3.7 μm. The structure of product is not changed according to the results of X ray powder deflection.