For the design of extraction columns time and cost can be saved, if it is based on lab-scale experiments that replace the pilot-plant scale experiments which are commonly used today. In lab-scale experiments the behavior of individual drops and drop swarms is investigated. System specific parameters of appropriate models are fitted to these experiments. These are used in simulations that describe the extraction process via drop-population balances. An overview over the historic development of this approach as well as todays solution methods is given. The simulation tool ReDrop can successfully describe the behavior of pulsed extraction columns and has been validated with several also industrial material systems. A perspective for future development is presented.