Liquid-liquid extraction procedure

Claim 1

A PROCESS FOR SEPARATING A MIXTURE OF TWO COMPONENTS HAVING DIFFERENT DISTRIBUTION COEFFICIENTS BETWEEN AN IMMISICIBLE PAIR OF SOLVENTS OF DIFFERENT SPECIFIC GRAVITIES WHICH COMPRISES: (1) INTRODUCING THE MIXTURE INTO AN INTERMEDIATE STAGE OF A MULTISTAGE COUNTER-CURRENT PRIMARY EXTRACTOR IN WHICH THE LIGHT SOLVENT IS INTRODUCED INTO THE BOTTOM END AND THE HEAVY SOLVENT IS INTRODUCED INTO THE TOP END, THE RATIO BETWEEN THESE SOLVENTS BEING SUCH THAT THE EXTRACTION FACTOR FOR ONE COMPONENT WILL BE GREATER THAN UTILITY AND THE EXTRACTION FACTOR FOR THE OTHER COMPONENT WILL BE LESS THAN UNITY; (2) CONTACTING PART OF THE ENRICHED HEAVY SOLVENT FROM THE PRIMARY EXTRACTOR IN A SECOND MULTISTAGE EXTRACTOR WITH FRESH LIGHT SOLVENT SO THAT THE EXTRACTION FACTOR FOR THE COMPONENT IN THE HEAVY SOLVENT WILL BE GREAT THAN UNITY; (3) SEPARATING THE DISSOLVED COMPONENT FROM THE OTHER PART OF THE ENRICHED HAVEY SOLVENT FROM THE PRIMARY EXTRACTOR; (4) RECYCLING THE HEAVY SOLVENT RECOVERED FROM STEPS (2) AND (3) TO A THIRD EXTRACTOR; (5) CONTACTING PART OF THE ENRICHED LIGHT SOLVENT FROM THE PRIMARY EXTRACTOR WITH THIS HEAVY SOLVENT IN THE THIRD EXTRACTOR SO THE EXTRACTION FACTOR FOR THE COMPONENT IN THE LIGHT SOLVENT WILL BE LESS THAN UNITY; (6) SEPARATING THE DISSOLVED COMPONENT FROM THE OTHER PART OF THE ENRICHED LIGHT SOLVENT FROM THE PRIMARY EXTRACTOR; (7) RECYCLING THE NOW FRESH LIGHT SOLVENT RECOVERED FROM STEPS (5) AND (6) TO THE SECOND EXTRACTOR.