Mechanical vs Chemical
Textile recycling sounds simple — old shirt in, new shirt out. The reality is two completely different technologies, both with serious limits. Here's what actually happens. 🔄
Mechanical recycling: shred and re-spin
Mechanical recycling is the old, simple method. It works like this:
1. Sort fabric by colour and material (hardest part — done by humans). 2. Cut buttons, zippers, and labels off. 3. Run the fabric through a shredder that pulls it back into raw fibre. 4. Re-spin the fibre into yarn. 5. Weave or knit new fabric.
This is how about 95% of all textile recycling happens today. It's cheap and uses little chemistry. The downside: the shredding process breaks the fibres into shorter pieces. Shorter fibres = weaker yarn = lower-quality fabric.
That's why most 'recycled cotton' garments are actually 20–30% recycled cotton blended with virgin cotton — to keep the strength up. 100% mechanically recycled cotton would feel rough and tear easily.
Chemical recycling: dissolve and rebuild
Chemical recycling is the newer, fancier approach. Instead of shredding, it dissolves fabric down to its molecular level using solvents and heat.
For cotton (which is cellulose), chemical recycling can produce a pulp that's then spun into Lyocell-style fibre — basically virgin-quality.
For polyester (which is a polymer called PET), chemical recycling depolymerises it back into its original chemical building blocks, which can be re-polymerised into new polyester at virgin quality.
The big advantage: fibres can be recycled again and again at full strength. The big disadvantages: it's energy-intensive, requires industrial chemistry, and is extremely expensive (often 5–10x the cost of virgin material). Companies like Renewcell (Sweden), Worn Again (UK), Circ (US), and Infinited Fiber (Finland) are scaling this — but together they handle a tiny fraction of global textile waste.
Why both technologies are stuck
Even the best textile recycling today recycles less than 1% of clothes back into new clothes. The bottlenecks:
- Sorting is mostly manual. Humans pick through donated piles to separate cotton, polyester, blends, by colour. Automation is improving (NIR scanners can identify materials in milliseconds) but isn't widespread. - Blends still defeat mechanical recycling. - Chemical recycling is too expensive to compete with $0.50/kg virgin polyester from oil. - Donated clothes arrive with buttons, zippers, sequins, prints — all of which contaminate the recycling stream. - Demand for 'recycled' clothing is real but small. Brands prefer 100% virgin because it's easier and cheaper.
Until regulations make virgin material more expensive (or recycling subsidised), the economics keep recycling stuck.
Hopeful developments
A few things give cautious hope:
- Renewcell (Sweden) opened a chemical recycling plant in 2022 that can turn old cotton clothes into new cotton fibre at industrial scale. Brands like H&M and Zara have started using their fibre. - The EU's Strategy for Sustainable Textiles (2022) requires all clothing sold in the EU to be 'designed for circularity' by 2030. - Extended Producer Responsibility (EPR) laws in France require clothing brands to fund the collection and recycling of what they sell. - AI-powered sorting machines from companies like Tomra and Refiberd are starting to make textile sorting fast and cheap.
Progress is slow but real. Today's <1% recycling rate is unlikely to be 50% by 2030, but it could realistically reach 10–20% — which would still mean billions of new garments made from old ones.
Key takeaways
- Mechanical recycling = shred + re-spin. Cheap, but shortens fibres each cycle.
- Chemical recycling = dissolve + rebuild. Virgin-quality output but expensive.
- Less than 1% of clothing is recycled into new clothing today.
- Sorting (still mostly manual), blends, and cheap virgin materials are the bottlenecks.
- Renewcell, Circ, and EU Extended Producer Responsibility laws are pushing change.
Try this
Visit a recycling website
Look up Renewcell, Circ, or Worn Again Technologies. Read their 'How it works' page. Try to explain the process in your own words to a family member in 60 seconds. Teaching forces you to understand.
Sort like a recycler
Take 10 garments from your wardrobe. Sort them into 4 piles: 100% cotton, 100% polyester, blended, other. How easy was it? How long did it take? Now imagine sorting 10 tonnes per hour with people from 10 countries who don't share a language. That's the textile recycling industry.
Cost-benefit roleplay
Imagine you run a brand. Virgin polyester costs $1/kg. Recycled polyester costs $4/kg. Customers don't reliably pay extra for recycled. Government won't subsidise. Argue for switching to 50% recycled anyway. What policies or business models would make it economically possible?
What's the main difference between mechanical and chemical textile recycling?
Mechanical recycling shreds fabric, which physically cuts the fibres shorter — so recycled material is weaker and usually has to be blended with virgin material. Chemical recycling dissolves fabric down to its molecules, which can then be rebuilt into virgin-quality fibre. Chemical is more powerful but expensive and energy-intensive.