Process for removing ASH-forming contaminants from a used oil and method for treating used oil.

摘要

A process for the reclaiming of used lubricating oils, particularly mixtures containing used oil from diesel engine crank cases, is provided to facilitate the separation of an oil phase from residual product in the production of an intermediate low-ash or a high-grade lube oil stock which method comprises: (a) contacting the used oil with an aqueous ammonium salt treating agent in the presence of a polyhydroxy compound, (b) removing a major portion of water, and (c) separating the oil phase from the resultant residual product. Optionally, (d) recovering the low-ash product of step (c) for use as a fuel oil, in grease formulations, or in the preparation of lubricating oil formulations. Optionally, the low-ash product of step (d) is (e) subjected to hydrotreating and thereafter (f) stripped.