Patent ID: 8801941

Claim:
An industrial method of removing cutting oil from granular tool steel swarf in an extraction vessel, said method comprising the steps of: (a) opening said extraction vessel and loading said tool steel swarf into said extraction vessel and forming a bed of said tool steel swarf in said extraction vessel; (b) closing said extraction vessel to seal said tool steel swarf therein; (c) removing at least about 89% by weight of said cutting oil from said tool steel swarf by flowing supercritical carbon dioxide through said bed of tool steel swarf at a pressure of at least about 5000 PSI and at a temperature of at least about 60° C. for a time of about 120 minutes or less; (d) separating said tool steel swarf from said supercritical carbon dioxide containing cutting oil; and (e) opening said extraction vessel and removing said tool steel swarf from said extraction vessel.