Waste oil can indeed be regenerated into hydraulic oil and transmission oil after proper treatment and additive preparation, but it needs to undergo strict process control and quality testing to ensure that its performance meets the requirements. The general process is as follows:
- Waste oil treatment steps
Pretreatment: remove moisture, impurities and light volatiles (such as solvents and gasoline and diesel residues).
Refining and purification: use sedimentation, centrifugation, filtration, vacuum distillation, solvent extraction or hydroprocessing to remove aging products, oxides and harmful components such as sulfur and nitrogen to improve the quality of base oil.
Decolorization and deodorization: use white clay or activated carbon to absorb residual impurities and color.
- Additive preparation
Base oil that has been regenerated usually needs to be added with additives to restore or enhance its performance. Different oils for different purposes require different additive formulas:
Hydraulic oil (such as L-HM 46, 68):
Antiwear agent (ZDDP, ASH-free AW)
Antioxidant (amines, phenols)
Rust inhibitor (organic phosphate, barium salt, etc.)
Antifoaming agent (silicone oil or polyether)
Anti-emulsifier (polyoxyethylene ether)
Transmission oil (gear oil) (such as GL-4, GL-5):
Extreme pressure antiwear agent (EP additives containing sulfur, phosphorus, chlorine, etc.)
Antioxidant (phenol amine)
Rust and corrosion inhibitor (barium salt, phosphate)
Viscosity index improver (polymethacrylate or OCP)
- Quality testing
Recycled hydraulic oil and transmission oil need to undergo the following tests to ensure compliance with standards:
Kinematic viscosity (40℃ and 100℃)
Viscosity index (VI)
Antioxidation performance (RBOT or TFOUT)
Extreme pressure and anti-wear performance (four-ball test, FZG gear test)
Water and impurity content
Copper corrosion test
Foam characteristics and emulsification properties
- Feasibility and market acceptance
The quality of recycled oil depends on the source and treatment process of the waste oil. Some high-end hydraulic oils and gear oils have high requirements for oxidation stability and cleanliness, and recycled oil may not be able to meet long-term use needs. If the target market has a high acceptance of recycled oil, it can be promoted as a low-cost industrial oil.
After efficient treatment and appropriate additive formulation, waste oil can be regenerated into hydraulic oil or transmission oil, but its performance depends on the quality of the base oil and the selection of additives. The application of recycled oil is mainly suitable for equipment that does not require too much oil performance, such as ordinary industrial equipment, old machinery, etc., while high-end equipment and long-life lubricants are still recommended to use products formulated with high-quality virgin base oil.