ANS:A - Pachuka tank

Among the listed options, Packed towers are not typically used in liquid-liquid extraction. Liquid-liquid extraction, also known as solvent extraction or partitioning, is a separation process in which a solute is transferred from one immiscible liquid phase to another immiscible liquid phase. The equipment commonly used in liquid-liquid extraction includes:

1. Agitated vessels: These vessels facilitate the mixing of the two immiscible liquids to enhance mass transfer and extraction efficiency.
2. Centrifugal extractors: Also known as liquid-liquid centrifuges or decanters, these devices use centrifugal force to separate the two immiscible liquid phases based on their densities.
3. Pachuka tank: Pachuca tanks, or air agitated leach tanks, are primarily used in hydrometallurgical processes for leaching minerals from ores. They are not specifically associated with liquid-liquid extraction processes.

Packed towers, on the other hand, are typically associated with gas-liquid or liquid-vapor separation processes, such as distillation, absorption, or stripping. They are not commonly used in liquid-liquid extraction, where the focus is on separating two immiscible liquid phases.