Solvent extraction process

A method for solvent-extracting an extractable component from a mixture including said extractable component and subdivided solids, comprising the steps of:

• (a) maintaining a vertically extending continuously or intermittently downwardly moving packed bed comprising said solids in a vertically extending extraction zone and introducing said mixture into an upper portion of said bed;
• (b) introducing into said upper portion of said bed a vaporizable liquid solvent capable of extracting at least a portion of said extractable component from said mixture;
• (c) providing a substantially continuous gaseous phase in contact with a lower portion of said bed;
• (d) maintaining a substantially continuous liquid phase comprising said solvent in contact with at least a lower part of said upper portion of said bed above said gaseous phase, said liquid phase and said gaseous phase having an interface at a vertically intermediate level of said bed, extracting said extractable component from said mixture of passing said solvent through said upper portion of said bed, and removing from said zone a liquid including said solvent and said extractable component;
• (e) preventing said liquid phase from flowing downwardly through said lower portion of said bed by maintaining said gaseous phase at a pressure sufficient to support said liquid phase thereon and a temperature sufficient to vaporize solvent adhering to solids in said lower portion of said bed;
• and
• (f) removing from said zone solids in said lower portion of said bed.