RECYCLING OF USED LUBRICATING OILS

Abstract

The main purpose of lubricants is to lubricate moving parts of the engine to reduce friction and wear, the engine depend greatly on the condition of lubricant oils. Because of this it is necessary to study the properties of lubricant oils. The recycling of used oils is very important for environment, they can protect the environment and save resources ( water & land ) from pollution by used motor oil ( used motor oil may contain toxic substances such as lead, benzene and zinc).

This research reports the change in oil properties after service operation. Four samples of new lubricant oils and seven samples of used lubricant oils ( after use in motor cars for 1000_5000 Km ) were analyzed, the seven samples of used lubricant oils have been recycled by means addition of acid, washing several times with distilled water, and at last adding solid caustic soda (sufficient to neutralize the acid). Some physical and chemical analyses have been carried for all samples (new, used and recycled ) according to the American Society for Testing and Materials ( A.S.T.M ). Infrared Spectroscopy Studies have been carried out. Atomic Absorption and X-ray Spectrometers have been used to check different elements in the samples. The results show that the flash point, density, Ni content, viscosity at 100Co and T.A.N improved in recycled oils in comparison with used oils. On the other hand the results showed that T.B.N, Zn and Ca content became less, and Cr content became higher in recycled oils. This study revealed that the used oils after removal of the insoluble impurities (recycled oils) could work more than once.