Аннотация
In the context of the increasing generation of waste motor oils and the limited possibilities for their safe disposal, evaluating their resource potential and identifying possible reuse pathways is an important scientific and practical task. This study aims to investigate the physicochemical properties of waste motor oils of different origins, including bus, automobile, and tractor oils, after operation and preliminary purification by simple filtration, in order to assess their potential use as secondary raw materials.A set of analytical methods was applied, including thermal analysis, FTIR spectroscopy, rheological testing, and elemental composition determination. The results showed that the waste oils had lower flash and ignition temperatures, indicating a decrease in thermal stability after use. The viscosity of the samples at 40 °С varied depending on their origin. Tractor oil showed lower viscosity values, which may be related to dilution with impurities, while automobile oil demonstrated increased viscosity due to the accumulation of oxidation and polymerization products.FTIR spectroscopy confirmed the presence of carbonyl compounds, indicating oxidative degradation processes, which were most pronounced in the automobile oil sample. Elemental analysis revealed elevated concentrations of Fe, Cu, Pb, and Zn, mainly associated with engine wear and contamination during operation.Although the studied waste motor oils are unsuitable for direct reuse as lubricants, they retain significant resource potential. Due to the presence of heavy hydrocarbon fractions and oxidation products, they can be considered secondary raw materials for road construction, bitumen modification, and composite material production, supporting environmental impact reduction and circular economy principles.