Reclamation of Waste Lubricating Oil

The standard re-refining process uses sulfuric acid to dissolve sludge. The oil phase is further cleaned by clay filtration. The process is so inefficient that one-third of the oil is lost and disposal of the acid solution is increasingly difficult. 

The water-alcohol method utilizes isopropyl alcohol to decompose metallic soaps. The mixture is then centrifuged to yield clean oil and a watery metallic sludge. Alcohol is recovered for reuse. 

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Higgins, RJ., B.A. Bishop and RL. Goldsmith, 1994, Reclamation of waste lubricating oil using ceramic membranes, presented at 3rd Int. Conf. Inorg. Membr., Worcester, MA,USA. 

Higgins, R., Bishop, B., and Goldsmith, R. (1993). Reclamation of waste lubricating oil using ceramic membranes, Proceedings of Third International Conference on Inorganic Membranes, pp. 447-456. 

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