Hexachlorocyclohexane isomer separation

Claim 1

THE PROCESS FOR SEPARATING THE ALPHA AND GAMMA ISOMERS OF BENZENE HEXACHLORIDE, INVOLVING A SERIES OF ALPHAISOMER AND OF GAMMA ISOMER-ENRICHMENT STEPS IN WHICH THE FEED FOR THE SERIES OF ALPHA ISOMER-ENRICHMENT STEPS IS DERIVED FROM THE SERIES OF GAMMA ISOMER-ENRICHMENT STEPS AND A SOLVENT LIQUOR FOR THE GAMMA ISOMER-ENRICHMENT STEPS IS DERIVED FROM THE SERIES OF ALPHA ISOMERENRICHMENT STEPS, WHICH INCLUDES: (1) DISSOLVING A CRYSTAL CAKE OF ISOMERS OF BENZENE HEXACHLORIDE CONTAINING AT LEAST THE ALPHA AND GAMMA ISOMERS IN A SECOND LIQUOR OBTAINED FROM A SECOND ALPHA ISOMER-ENRICHMENT STEP IN THE PROCESS; (2) EFFECTING CRYSTALLIZATION OF AT LEAST ALPHA AND GAMMA ISOMERS FROM THE SOLUTION SO PRODUCED; (3) SEPARATING THE SO-OBTAINED CRYSTALS BY FLUID CLASSIFICATION TO YIELD A FIRST FRACTION OF CRYSTALS IN WHICH THE RATIO OF GAMMA ISOMER TO ALPHA ISOMER IS ENHANCED AND A FIRST SUSPENSION OF CRYSTALS IN WHICH THE RATIO OF ALPHA ISOMER TO GAMMA ISOMER IS ENHANCED; (4) RECOVERING FROM THE SAID FIRST SUSPENSION OF CRYSTALS A FIRST LIQUOR USED IN THE PREPARATION OF THE CRYSTAL CAKE OF ISOMERS FOR STEP (1) AND A FIRST PRECIPITATE CONTAINING ALPHA-ISOMER-ENHANCED CRYSTALS; (5) DISSOLVING THE SAID GAMMA-ISOMER-ENHANCED FIRST FRACTION OF CRYSTALS IN A THIRD LIQUOR OBTAINED FROM A THIRD ALPHA ISOMER-ENRICHMENT STEP IN THE PROCESS; (6) EFFECTING CRYSTALLIZATION OF AT LEAST ALPHA AND GAMMA ISOMERS FROM THE SOLUTION SO PRODUCED; (7) SEPARATING THE SO-OBTAINED CRYSTALS BY FLUID CLASSIFICATION TO YIELD A SECOND FRACTION CRYSTALS IN WHICH THE RATIO OF GAMMA ISOMER TO ALPHA ISOMER IS ENHANCED AND A SECOND SUSPENSION OF CRYSTALS IN WHICH THE RATIO OF ALPHA ISOMER TO GAMMA ISOMER IS ENHANCED; (8) COMBINING SAID SECOND ALPHA-ENHANCED-SUSPENSION OF CRYSTALS AND THE FIRST ALPHA-ENHANCEDPRECIPITATE RECOVERED FROM THE SAID FIRST SUSPENSION OF CRYSTALS; (9) RECOVERING FROM SAID COMBINED SECOND SUSPENSION AND FIRST PRECIPITATE THE SAID SECOND LIQUOR USED IN STEP (1) OF THE PROCESS AND A SECOND PRECIPITATE CONTAINING A HIGHER RATIO OF ALPHA ISOMER TO GAMMA ISOMER THAN THE RATIO OF THE SAID PRECIPITATE; AND, (10) CONTINUING THE PROCESS TO PRODUCE SUBSTANTIALLY PURE GAMMA ISOMER.