Preparation and recovery of olefin polymers

Claim 1

PROCESS FOR THE PRODUCTION OF HIGH DENSITY HIGHLY CRYSTALLINE POLYMER OF ETHYLENE WHICH COMPRISES POLYMERIZING ETHYLENE IN SOLUUTION IN CYCLOHEXANE IN THE PRESENCD OF PARTICLES OF CATALYST COMPRISING CHROMIUM OXIDE, AT LEAST PARTLY IN HEXAVALENT FORM, SUPPORTED ON SILICA-ALUMINA, AT A PRESSURE OF ABOUT 300 TO 500 POUNDS PER SQUARE INCH ABSOLUTE AND A TEMPERATURE OF ABOUT 275 TO 290*F., THE ETHYLENE CONTENT OF SAID SOLUTION BEING ABOUT 12 TO 15%, AND THE CHROMIUM CONTENT OF SAID CATALYST BEING ABOUT 2 TO 3%, PRODUCING A SOLUTION OF A HIGH DENSITY HIGHLY CRYSTALLINE POLYMER OF ETHYLENE IN SAID SOLVENT CONTAINING SUSPENDED CATALYST, REMOVING CATALYST FROM SAID SOLUTION AND SPRAYING THE RESULTING OSLUTION CONTAINING ABOUT 2 TO 4.5% POLYMER, AT A TEMPERATURE OF ABOUT 270 TO 310*F., INTO A CONFINED STREAM OF COOLER WATER, PASSING THE RESULTING MIXTURE COMPRISING PRECIPITATED POLYETHYLENE IN CYCLOHEXANE AND WATER AT SUPERATMOSPHERIC PRESSURE SUFFICIENT TO MAINTAIN THE CYCLOHEXANE AND WATER IN THE LIQUID PHASE IN A STREAM THROUGH A CONFINED ZONE, THE RESIDENCE TIME OF SAID MIXTURE IN SAID CONFINED ZONE BEING AT LEAST 5 SECONDS, THE TEMPERATURE OF THE MIXTURE IN SAID CONFINED ZONE BEING BABOUT 110 TO 130*F. AND THE RATIO OF WATER TO POLYMER SOLUTION BEING ABOUT 2:1 TO 5:1, PASSING THE RESULTING MIXTURE INTO A HEATED ZONE AT A PREESSURE SUFFICIENTLY LOW TO CAUSE SAID CYCLOHEXANE TO EVAPORATE AND THEREAFTER REEMOVING WATER FROM SAID PREECIPITATED POLYETHYLENE TO PRODUCE POROUS PARTICLES OF POLYETHYLENE HAVING, WHERE DRIED, A BULK DENSITY OF AT LEAST 20 POUNDS PER CUBIC FOOT.