1. FRACTIONAL CRYSTALLIZATION APPARATUS COMPRISING, IN COMBINAION, A FIRST ELONGATED CYLINDRICAL CHAMBER HAVING INLET AND OUTLET MEANS, A HEAT-EXCHANGE JACKET HAVING INLET AND OUTLET MEANS SURROUNDING SAID FIRST CHAMBER, AUGER-SCRAPER MEANS AXIALLY DISPOSED IN SAID FIRST CHAMBER AND ADAPTED TO PUMP MATERIAL THERETHROUGH AND SCRAPE THE INNER WALL THEREOF, A SECOND ELONGATED CYLINDRICAL CHAMBER HAVING A VERTICAL BAFFLE DISPOSED THEREIN DIVIDING SAID CHAMBER INTO TWO ZONES COMMUNICATING ACROSS SAID BAFFLE AT THE TOP OF SAID CYLINDER, PLURAL AGITATORS WITHIN SAID SECOND CYLINDRICAL CHAMBER, ONE BEING POSITIONED ON EACH SIDE FO THE BAFFLE, SAID FIRST AND SECOND CHAMBERS CONNECTED BY FIRST AND SECOND CONDUITS ADAPTED TO PROVIDE A CIRCULAR PATH THERETHROUGH, A THIRD ELONGATED CYLINDRICAL CHAMBER COMMUNICATING WITH THE OUTLET OF SAID FIRST CHAMBER, STATIONARY FILTRATION MEANS POSITIONED IN SAID THIRD CHAMBER WITH MEANS FOR WITHDRAWING LIQUID THEREFROM, AND MELTING ZONE MEANS ASSOCIATED WITH SAID THIRD CHAMBER WITH MEANS FOR WITHDRAWING MELT THEREFROM.