The annular centrifugal extractors (ACEs) are based on the principle of Taylor-vortex flow. They essentially consist of two co-axial cylinders where the outer one is stationary and the inner one is rotating. They provide very high values of mass transfer coefficient in the annular region because of high levels of power consumption per unit volume. What is more, the rotor separates two phases into the other without any carryover of one phase. With these two advantages, they are used for several applications of liquid-liquid extraction where low inventories are desired. They include metal recovery and purification in the mining industry, processing of uranium and high plutonium fuels, caustic side solvent extraction to remove cesium from nuclear waste, hydrochloric washing of polymer phases, bromination and subsequent efficient separation of brominated polymer from aqueous phase.
Ri Hui Myong, a researcher at the Faculty of Thermal Engineering, investigated the phase separation characteristics and extraction characteristics of TBP-NaNO3 system in a 50mm annular centrifugal extractor with respect to the rotational speed and the inlet phase ratio, and derived an empirical formula for the throughput of NaNO3 under a given operating condition.
The maximum throughput of TBP-NaNO3 system in the 50mm annular centrifugal extractor was 12.6kg/h at a rotational speed of N=2 500r/min and an inlet phase ratio of Ro/a=1.
You can find more information in his paper “Phase Separation and Extraction Characteristics of TBP-NaNO3 System in an Annular Centrifugal Extractor” in “Proceedings of KUTIC-2025”.