Re-refining of lubricating oils

Claim 1

A PROCESS FOR REMOVING IMPURITIES FROM A USED HIGH DETERGENT LUBRICATING OIL COMPRISING ADMIXING AT LEAST ABOUT ONE PART BY VOLUME OF AN AQUEOUS CLEANSING AGENT AT A TEMPERATURE BETWEEN ABOUT 50 TO 100*F. TO EACH THREE PARTS BY VOLUME OF USED HIGH DETERGENT LUBRICATING OIL, AGITATING SAID CLEANSING AGENT AND SAID HIGH DETERGENT LUBRICATING OIL AT A TEMPERATURE WITHIN THE AFORESAID RANGE UNTIL AN EMULSION IS FORMED, HEATING SAID EMULSION TO EFFECT BREAKING OF THE EMULSION, AND SEPARATING THE CLEANSED OIL FROM THE SPEND AQUEOUS CLEASING AGENT AND FROM THE PRECIPITATED SOLIDS; SAID AQUEOUS CLEANSING AGENT COMPRISING A SUFFICIENT QUANTITY OF A MIXTURE OF POLYOXYALKYLENE COMPOUNDS TO EFFECT EMULSIFICATION AND POSSESSING HIGH DETERGENT ACTIVITY AT ABOUT ROOM TEMPERATURE BUT PRACTICALLY NO DETERGENT ACTIVITY AT AN ELEVATED TEMPERATURE OF ABOUT 150 TO 200*F. CONSISTING OF OXYPROPYLENE GROUPS, OXYETHYLENE GROUPS AND NUCLEUS OF A NITROGEN CONTAINING REACTIVE HYDROGEN COMPOUND HAVING NOT MORE THAN 6 CARBON ATOMS AND BEING SELECTED FROM THE GROUP CONSISTING OF AMMONIA, PRIMARY ALKYLAMINES, ALKYLENE POLYAMINES, ALKYLPIPERAZINES, HYDROXYLAMINE AND AMINOSITUTED ALKYLPIPERAZINES, HYDROXYLAMINE AND AMINOPHENOL, THE STRUCTURE OF THE COMPOUNDS BEING SUCH THAT SUBSTANTIALLY ALL OF THE OXYPROPYLENE GROUPS ARE PRESENT IN OXYPROPYLENE CHAINS THAT ARE ATTACHED TO THE REACTIVE HYDROGEN COMPOUND AT THE SITES OF THE REACTIVE HYDROGEN ATOMS, AND SUBSTANTIALLY ALL OF THE OXYETHYLENE GROUPS ARE PRESENT IN OXYETHYLENE CHAINS THAT ARE ATTACHED TO THE ENDS OF THE OXYPROPYLENE CHAINS, THE AVERAGE MOLECULAR WEIGHT OF THE OXYPROPYLENE CHAINS BEING AT LEAST ABOUT 2500 AND UP TO ABOUT 3000, AND THE OXYETHYLENE GROUPS BEING PRESENT IN AMOUNT SO AS TO CONSTITUTE ABOUT 10 TO ABOUT 30 WEIGHT PERCENT OF THE MIXTURE OF SAID POLYOOXYALKYLENE COMPOUNDS.