A mixer-settler extractor
is a type of liquid-liquid extraction equipment used to separate and extract specific components from a liquid mixture. It consists of a series of mixer and settler units arranged in a sequence.
The process begins with the mixer unit, where the immiscible liquid phases (usually an aqueous and an organic phase) are brought into contact and mixed together. The mixing facilitates the transfer of the desired components from one phase to the other. The mixer unit typically consists of rotating blades or agitators that promote thorough mixing and mass transfer between the two phases.
After the mixing step, the mixture flows into the settler unit. In the settler, the two liquid phases are allowed to separate due to differences in their densities. The heavier phase settles at the bottom while the lighter phase rises to the top. The settler unit is designed in a way that allows the separated phases to be collected separately.
The separated phases are then further processed or directed to subsequent mixer-settler stages for additional extraction or purification steps. By repeating the mixer-settler stages, a higher degree of separation and extraction can be achieved.
Mixer-settler extractors are commonly used in various industries, including chemical processing, pharmaceuticals, mining, and environmental remediation. They are especially useful in situations where the components to be extracted have different solubilities in different solvents or where there is a need to remove impurities or contaminants from a liquid mixture.
It's worth noting that while mixer-settler extractors are effective in liquid-liquid extraction processes, they may have limitations in terms of throughput, scalability, and the types of components that can be efficiently separated. Other extraction techniques such as centrifugal extractors, membrane-based extraction, or continuous countercurrent extraction systems may be employed for specific applications that require higher efficiency or larger-scale operations.