Solvent Extraction and Mass Transfer Assessment in Novel Extraction Technologies

An agitated tube reactor (ATR) has been converted from a commercially available flow chemistry reactor into a working solvent extraction contactor. It has been determined that the ATR has potential to be an industrial option for solvent extraction. Mass transfer coefficients have been calculated for a wide range of agitation frequencies and residence times using Cu(II) extraction by extractant Mextral® 84H. Mass transfer has then been compared to a Taylor-Couette Disc Contactor, and a novel design, presented in this work, called a D-cell contactor. Varying liquid volume by including an air phase has been shown to improve mass transfer within the ATR. The motion of liquid in the tube at each volume has also been monitored and compared against power per volume and droplet diameter calculations. In most operational parameters, liquid in the ATR is found to bypass agitation, therefore not achieving the expected extraction equilibrium. The volume of unmixed liquid is determined and a mass transfer coefficient for the mixed liquid is calculated. Based on the current design, optimum parameters are found when a tube is half filled and subject to an agitation frequency of 5 Hz. With these operational conditions, the ATR is shown to mix 95% of the fluid and reaches equilibrium within approximately 160 s. The viability of the ATR as a solvent extractor has been compared against a Taylor-Couette Disc Contactor and a Pulsed Column. It is seen that at 5 Hz, with 50% fill fraction, that the ATR produces a comparable mass transfer coefficient to a pulsed column correlation, as well as other mass transfer coefficients in literature.