Recycling of used lubricating oil may seem like nothing more than a dirty byproduct, but it's actually a valuable resource when managed correctly. Instead of ending up in landfills or polluting waterways, used oil can be collected and reprocessed into usable materials, significantly reducing environmental impact and conserving raw resources. So, how exactly is used oil recycled? Let's break it down.

What Is Used Lubricating Oil?

Used oil is any petroleum-based or synthetic oil that has become contaminated after use. Over time, engine oil, industrial lubricants, and hydraulic fluids collect dirt, metal particles, water, or chemicals, making them ineffective. But this doesn't mean they’re useless. In fact, with proper treatment, used oil can be turned into fresh, high-quality lubricants or used as an alternative fuel source.

Typical Recycling Processes

There are several established methods for recycling used oil, each with its own technology, cost, and output quality. The most common ones include:

1. Reconditioning (or Simple Cleaning)

Best for: On-site reuse (industrial use)

This is the most basic form of recycling. It involves:

• Settling or centrifugingto remove water and solids
• Filtrationto eliminate particulates
• Additivesto restore lubrication properties

While cost-effective, this method doesn’t remove all contaminants and is mainly suitable for non-critical applications.

2. Re-refining (Regeneration)

Best for: Producing base oil for new lubricants

This is the most advanced and preferred method globally. It involves:

• Dehydration– removes water and light hydrocarbons
• Vacuum distillation– separates useful oil fractions from impurities
• Hydrotreating or hydrofinishing– uses hydrogen gas and a catalyst to remove chemical impurities and enhance performance

The output is almost identical to virgin base oil, and the process is energy-efficient compared to refining crude oil.

3. Burning for Energy Recovery

Best for: Industrial furnaces and cement kilns

Used oil can also be burned as fuel in specially designed equipment:

• It is filtered to remove heavy metals and particulates
• Burned in furnaces, boilers, or kilns for heat generation

While this recovers energy, it doesn’t reclaim the oil’s original value, so it's considered a lower-tier option.

4. Chemical or Solvent Extraction (Less Common)

Best for: Specialized applications

This method uses solvents or chemicals to separate the base oil from contaminants. Though it can be effective, it's less commonly used due to higher costs and chemical handling risks.

Environmental & Economic Benefits

Recycling just 1 gallon of used oil can produce as much clean lubricating oil as 42 gallons of crude oil. Plus:

Reduces greenhouse gas emissions

Cuts down on land and water pollution

Supports circular economy goals

Final

Recycling used lubricating oil isn't just an industrial process—it's a necessity in our drive toward sustainability. Whether you're a vehicle owner, industrial user, or part of a maintenance team, ensuring used oil is properly collected and directed to a certified recycler can make a significant difference.

Tip: Always store used oil in sealed containers and take it to an approved recycling center. Never dump it down the drain or into the environment.