Polymerization catalyst recovery

Claim 1

A PROCESS FOR THE SEPARATION OF A SOLID CATALYST COMPRISING CHROMIUM OXIDE, CONTAINING HEXAVALENT CHROMIUM, ASSOCIATED WITH A SUPPORTING MATERIAL SELECTED FROM THE GROUP CONSISTING OF SILICA, ALUMINA, THORIA, ZIRCONIA, AND COMPOSITES THEREOF FROM A SOLUTION OF A POLYMER OF A 1-OLEFIN HAVING A MAXIMUM OF 8 CARBON ATOMS PER MOLECULE AND NO BRANCHING NEARER THE DOUBLE BOND THAN THE 4 POSITION WHICH COMPRISES INTRODUCING SAID POLYMER SOLUTION CONTAINING SAID CATALYST AT A TEMPERATURE BETWEEN ABOUT 200* F. AND ABOUT 400* F. TO THE FIRST CENTRIFUGING ZONE MAINTAINED UNDER SUPERATMOSPHERIC PRESSURE WITH AN INERT GAS, REMOVING FROM SAID ZONE AS PRODUCT A FIRST STREAM COMPRISING A SUBSTANTIALLY CARALYST-FREE POLYMER SOLUTION, REMOVING A SECOND STREAM CONTAINING CATALYST, SOLVENT AND POLYMER, INTRODUCING THE SECONG STREAM TO A SECOND CENTRIFUGING ZONE MAINTAINED UNDER SUPERATMOSPERIC PRESSURE WITH AN INERT GAS, REMOVING FROM THE SECOND ZONE A QUANTITY OF MATERIAL CONTAINING POLYMER, SOLVENT AND A SMALL AMOUNT OF CATALYST, RECYCLING SAID MATERIAL TO THE FIRST CENTRIFUGING ZONE AND REMOVING FROM THE SECOND ZONE A STREAM COMPRISING SOLVENT, CONCENTRATED IN CATALYST.