Process for recovering rolling oil

Claim 1

A PROCESS FOR TREATING THE COOLING AND LUBRICATING LIQUID CONTAINING A FATTY ROLLING OIL EMULSION AND COOLING WATER USED I-N THE PROCESS OF CONTINUOUS COLD ROLLING OF STEEL STRIP, COMPRISING, THE STEPS OF COLLECTING FROM THE MAIN BODY OF THE LIQUID SEDIMENTARY AND SUPERNATANT SLUDGE CONTAINING THE OIL EMULSIFIED WITH WATER AND CONTAMINATED WITH IMPURITIES, ADDING TO THE OIL FROM ABOUT 8 TO 27 PERCENT BY WEIGHT THEROF OF MINERAL ACID SELECTED FROM THE GROUP CONSISTING OF H2SO4, BEFORE SUBSTANTIAL CHEMICAL DETERIORATION OF THE OIL HAS OCCURRED, AT LEAST ABOUT 1 TO 2 PERCENT ACID BASED ON THE GROSS WEIGHT OF SAID SLUDGE BEING ADDED WITHIN ABOUT 48 HOURS AFTER THE USE OF THE OIL IN COLD ROOLING AS AFORESAID, MAINTAINING THE MIXTURE AFTER THE DDITION OF ALL OF THE ACID, AT AN ELEVATED TEMPERATURE UNTIL THE EMULSION IS BROKEN AND A WATER-AND-OIL INSOLUBLE PRECIPITATE IS FORMED, AND SEPARATING THE OIL FROM THE MIXTURE READY FOR REUSE IN THE ROLLING PROCESS.