Abstract
The effects of feeding location, stirring speed and apparent average residence time on oxalate crystals size and distribution, tackiness of the product on the walls of reactor and stirring paddle were investigated in a vortex continuous precipitator at 45 °C. The results showed agglomeration happened during nucleation and crystals growth of U(IV) oxalate. Both local supersaturations and agglomeration maked the particles size distribution of U(IV) oxalate from 10–100 µm and the average sizes 35–45 µm. On the other hand, when the nucleation process were controlled to happen in the forced vortex zone, two feeding locations: (a) both oxalic acid and U(IV) nitrate solution into the forced vortex zone, (b) oxalic acid into the free vortex and U(IV) nitrate solution into the forced vortex, tackiness of the crystals on the wall of the precipitator could be effectively avoided.
Intense foreshock swarm preceding the 2019 MW 6.5 Ambon (Seram, Indonesia) earthquake and its implication for the earthquake nucleation process
