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Used Lubricating Oils
3.1 INTRODUCTION
Used lubricating oil—often referred to as waste oil without further qualication—is
any lubricating oil, whether rened from crude or synthetic components, which has
been contaminated by physical or chemical impurities as a result of use.
Lubricating oil loses its effectiveness during operation due to the presence of cer-
tain types of contaminants. These contaminants can be divided into: (1) extraneous
contaminants and (2) products of oil deterioration.
Extraneous contaminants are introduced from the surrounding air and by metallic
particles from the engine. Contaminants from the air are dust, dirt, a ...