Abstract: In this article a new arrangement of extraction cascade—multiple stage counter-current extraction processwith alternating extraction and stripping is presented.The effects of increasing mass-transfer rate and decreas-ing the number of extraction stage in an extraction process may be obtained by adopting this new arrange-ment.Extraction cascade calculation for two extraction systems-extraction of iron with N,N-bis-(l-methl-heptyl)acetyl amide(N-503)* and extraction of H_3PO_4 with DBSO has been carried out and the experi-ment has been done with the former system.The results of calculation and experiment show that the extraction efficiency increases significantly byadopting this new alternating arrangement,compared with a commun multiple stage counter-current process.The new alternating extraction and stripping arrangement may be called alternating extraction process.

摘要： In this article a new arrangement of extraction cascade—multiple stage counter-current extraction processwith alternating extraction and stripping is presented.The effects of increasing mass-transfer rate and decreas-ing the number of extraction stage in an extraction process may be obtained by adopting this new arrange-ment.Extraction cascade calculation for two extraction systems-extraction of iron with N,N-bis-(l-methl-heptyl)acetyl amide(N-503)* and extraction of H_3PO_4 with DBSO has been carried out and the experi-ment has been done with the former system.The results of calculation and experiment show that the extraction efficiency increases significantly byadopting this new alternating arrangement,compared with a commun multiple stage counter-current process.The new alternating extraction and stripping arrangement may be called alternating extraction process.