Reclamation of used hydraulic oil

In an attempt to develop a nonpolluting method for used oil disposal, sharp sand bed filtration and the continuous elution technique were used on a bench scale to carry out the reclamation of used industrial hydraulic oils. Both processes gave quantitative yields of reclaimed oils. Assessment of the qualities of these oils using standard ASTM procedures and IR spectroscopy showed that the reclaimed oils are similar to the base oil from which the hydraulic oil was formulated. The metallic impurities in the used oil were completely removed, and the oils totally dehydrated. The yields from the continuous elution process were generally higher than those of the sharp sand filtration technique.