A review of application of annular centrifugal contactors in aspects of mass transfer and operational security

The annular centrifugal contactors (ACCs) have been used for liquid-liquid extraction in bench scale/pilot-plant tests. In view of good hydraulic properties and high mass-transfer efficiency, the state-of-the-art of extraction process using ACC/ACCs can satisfy the mass transfer enhancement, cascade and operational security liquid-liquid extraction processes. The many investigations of ACCs have been focused on the flow instabilities, multiphase flows, axial mixing, etc. The published literatures on these aspects have been critically analyzed and presented in a coherent manner. But in this review, the summaries of the application of ACCs in many specific extraction processes were presented, and how to optimize the operation conditions to reach good hydraulic properties were summarized using the designed equipments of ACCs. The good hydraulic properties were significant to the quick and excellent separation of the immiscible phase, and the high mass-transfer efficiency for liquid-liquid extraction were performed by cascade of ACCs. The advantages and disadvantages of the ACCs were discussed in detail. Recommendations have been made for future work with aim of more information for the application of the hydrometallurgical process.