Lubrication Impurity Removal Review
Lubrication Impurity removal: Once the oil is
separated into fractions, it must be further treated to
remove impurities, waxy resins, and asphalt. Oils that have
been highly refined are usually referred to as premium
grades to distinguish them from grades of lesser quality in
the producer's line of products. However, there are no
criteria to establish what constitutes premium grade.