A robust multistage mesoflow reactor for liquid–liquid extraction for the separation of Co/Ni with cyanex 272

• A multistage counter-current mesoflow solvent extraction setup was evaluated.
• A robust phase separator has been developed.
• Several mesoflow mixers were evaluated.
• Separation of a Co/Ni mixture with cyanex 272 was performed.

Solvent extraction is a key principle for separations of components often requiring relatively large separation times due to large droplet size distributions. A continuous mesoflow reactor setup was evaluated for solvent extraction and phase separation in terms of efficiency of Co/Ni separation with cyanex 272 as extractant in a kerosene mixture. Several mixer types have been evaluated for the solvent extraction capability combined with a thin film coalescer/separator, expediting separation times, resulting in a settling volume that was only 1–2 times the volume of the mixer effectively reducing total residence time compared to classic mixer-settlers, where the ratio is 4–8 times higher. This was mainly attributed to the droplet homogeneity generated in the mixer, resulting is a short separation time. The thin film coalescer partitions in the settler expedited the phase separation further reducing the required settler volume. This paper shows that continuous mesoflow reactor setups can be utilized for small-scale liquid extractions with narrowly defined droplet sizes, enhancing the phase separation time, making it a viable screening utility. It also shows that the useful volume is much higher than those for conventional mixer-settler with a phase-separation-volume-to-equilibrium-volume ratio of 1–2 compared to 4–8 for the conventional mixer-settler expediting parameter screening.