Abstract: Commercially valuable oil is recovered from refinery-produced, Resource Conservation and Recovery Act classified, hazardous waste oil sludges by a series of volatilizing and condensing steps (which may vary depending on the oil, water, and solids content of the sludge) resulting in the production of nonhazardous water and solid waste byproducts. A pumpable, low viscosity, high oil- and/or water-content sludge is first centrifuged to separate free oil and water. If the waste sludges are acidic or if nickel is present in the sludges in sufficient quantities so as to result in unacceptable levels in the TCLP leach filtrate, a base (such as calcium oxide) is admixed with the thick waste oil sludge, centrifuge solids, or other sludges low in oil and/or water content to render the sludges basic. The basic, admixed sludges are heated to volatilize the contained water and oil. Dry, friable, deoiled solids are recycled with the oily sludge feed to prevent material agglomeration and heat exchanger fouling.

Abstract: Commercially valuable oil is recovered from refinery-produced, Resource Conservation and Recovery Act classified, hazardous waste oil sludges by a series of volatilizing and condensing steps (which may vary depending on the oil, water, and solids content of the sludge) resulting in the production of nonhazardous water and solid waste byproducts. A pumpable, low viscosity, high oil- and/or water-content sludge is first centrifuged to separate free oil and water, while the thick waste oil sludge, centrifuge solids, or other sludges low in oil and/or water content are heated to volatilize the contained water and oil. Dry, friable, deoiled solids are recycled with the oily sludge feed to prevent material agglomeration and heat exchanger fouling. Oil and water vapor from the high-temperature volatilization apparatus is recycled as an indirect heat source to the low-temperature volatilization apparatus.

Abstract: A process for the recovery of molybdenum values from leach muds of molybdenite concentrates which have been roasted in air to convert molybdenum sulfide to molybdenum trioxide and subsequently leached with an aqueous alkaline solution for the recovery of soluble molybdenum salts. Leach mud is treated by the process of this invention by repulping the leach mud with aqueous ammonium hydroxide under pressure, at a temperature in the range of about 50 to 150.degree. C. for a period of 2 or more hours after which undissolved solid material is separated from the ammoniacal leach solution and repulped with an aqueous caustic leach solution at a temperature in the range of 50.degree. to 150.degree. C. for a period of 2 to 4 hours. Undissolved solid material is separated from the caustic leach solution and both the ammoniacal and the caustic leach solutions processed for the recovery of molybdenum salts therefrom.