Centrifugal Extractor vs Mixer Settler
2026-03-16
Introduction
Solvent extraction is widely used in industries such as hydrometallurgy, rare earth processing, pharmaceuticals, and fine chemicals. Two of the most commonly used extraction technologies are the centrifugal extractor and the mixer settler.
Both systems are designed to separate immiscible liquid phases and transfer target components between them. However, they differ significantly in terms of efficiency, equipment size, operation, and investment.
In this article, we compare centrifugal extractor vs mixer settler to help engineers and plant designers choose the right solvent extraction equipment.
What Is a Centrifugal Extractor?
A centrifugal extractor is a compact extraction device that integrates mixing and phase separation in a single rotor unit. The rotor spins at high speed, generating strong centrifugal force that promotes rapid mixing and fast separation of the organic and aqueous phases.
Key Features
High-speed mixing and separation
Compact equipment design
Continuous operation
Extremely fast phase disengagement
Typical Applications
Centrifugal extractors are widely used in:
Copper SX-EW processes
Rare earth element extraction
Pharmaceutical intermediate purification
Lithium battery recycling
Due to their high efficiency, centrifugal extractors are increasingly used in modern chemical and metallurgical plants.
What Is a Mixer Settler?
A mixer settler is a traditional liquid-liquid extraction system consisting of two sections: a mixing chamber and a settling tank.
In the mixer section, two liquid phases are mechanically stirred to promote mass transfer. The mixture then flows into the settler section, where gravity allows the phases to separate naturally.
Key Features
Simple design
Easy operation
Large processing capacity
Widely used in large hydrometallurgical plants
Mixer settlers are commonly used in:
Copper solvent extraction plants
Nickel and cobalt recovery
Rare earth separation processes
Centrifugal Extractor vs Mixer Settler: Key Differences
Equipment Size
Centrifugal extractors are much more compact than mixer settlers. A centrifugal extraction system may occupy only 10–20% of the space required for a mixer settler plant.
This makes centrifugal extractors ideal for plants with limited installation space.
Separation Speed
Phase separation in centrifugal extractors occurs within seconds due to strong centrifugal force.
In contrast, mixer settlers rely on gravity separation, which requires a much longer residence time.
Process Efficiency
Centrifugal extractors typically provide higher mass transfer efficiency due to intense mixing and rapid separation.
This allows plants to achieve higher extraction efficiency with fewer stages.
Solvent Inventory
Centrifugal extractors require much less solvent inventory compared with mixer settlers, which improves process safety and reduces chemical costs.
Investment Cost
Mixer settlers often have lower equipment cost per stage, but they require larger installation areas and higher solvent inventory.
Centrifugal extractors may have higher unit equipment cost but offer advantages in efficiency, footprint, and automation.
When Should You Choose a Centrifugal Extractor?
Centrifugal extractors are ideal when:
Installation space is limited
Fast phase separation is required
Process efficiency needs to be maximized
Solvent inventory must be minimized
Continuous automated operation is preferred
These advantages make centrifugal extraction technology increasingly popular in modern chemical processing plants.
When Is a Mixer Settler More Suitable?
Mixer settlers are still widely used when:
Large processing capacity is required
Installation space is sufficient
Lower equipment investment is preferred
Traditional solvent extraction processes are already established
Many large hydrometallurgical plants still rely on mixer settler systems.
Conclusion
Both centrifugal extractors and mixer settlers play important roles in solvent extraction processes. The choice depends on process requirements, plant layout, and investment considerations.
For modern plants seeking compact design, high efficiency, and automated operation, centrifugal extractors are becoming an increasingly attractive solution.
