One of the important way of classifying extractions is based on the mode of operation, gererally reffered as batch or continuous.

The terms batch and continuous basically points to how the sample or u can say feed is placed into the system that is extraction apparatus.

In this video we would only discuss about continuous extraction... I have already uploaded video on batch extraction, u can watch that also.

In continuous mode of extraction, An immiscible extracting liquid is kept flowing continuously through the solution from which a solute is to be extracted.

And this kind of extraction is carried out when the partition coefficient of solutes is low.

What does this mean...

partition coefficient here reffers to the
distribution ratio .., in easy way we can say the ratio of the solute between the two phases....

In this type of extraction Although there is not enough time to establish equilibrium, but still a solute is extracted continuously.

now, the techniquie demands a special kind of extractor,

and the need of extractor depends on whether extracting solvent or we can say solvent used for extraction is lighter or heavier than sample solution from which the solute is tobbe extracted.