Clean and green: new microrecycling technique transforms aluminium

A discovery by the UNSW Sustainable Materials Research and Technology (SMaRT) Centre could start a ‘green aluminium’ manufacturing revolution and bolster efforts to advance Australia’s manufacturing industry.

Backed by industry partner Nespresso, researchers at the SMaRT Centre have found a way to recover aluminium from complex, multilayered packaging. The new technique is based on the microrecycling science pioneered by the SMaRT Centre under the leadership of its Director, Professor Veena Sahajwalla, and builds on their waste materials innovations including Green Steel and Microfactorie technologies.

The research demonstrates that polymer-laminated aluminium packaging (PLAP) materials — such as post-consumer food and coffee packaging — can be sustainably recycled into high-quality aluminium and could be a potential source of high-energy hydrocarbon products.

Green aluminium

“We developed green steel technology, where we extract hydrogen and carbon from old rubber tyres and plastic as an innovative and green pathway in steelmaking, and we now can develop new ‘green aluminium’ with our novel technique called thermal disengagement technology (TDT),” Professor Sahajwalla said.

“Recycling using new technologies can be a foundation for the manufacturing of high-quality materials from our waste resources, as we seek to develop greater sovereign capability along with economic prosperity.”

Key industry partner Nespresso has been an important stakeholder in the research and is excited by its potential to be part of the new manufacturing and sustainability agenda announced by the federal government in its 2020 Budget package.

Nespresso Australia and Oceania Technical and Quality Manager Marta Fernandes said, “This collaboration aligns with Nespresso’s commitment to circularity and our existing investment in building a local recycling scheme that has enabled all of our customers in Australia, both residential and business, to recycle their used Nespresso aluminium capsules via more than 19,000 collection points, with four different options to make it as easy as possible for customer[s] to recycle.

“Recycling is a big part of the company’s broader sustainability efforts, which include bringing capsules made from 80% recycled aluminium to the Australian market, sourcing over 94% of coffee through its AAA Sustainable Quality program and committing to be fully carbon neutral by 2022. We are proud to be continuing our research collaboration with Veena and her UNSW SMaRT Centre team because there is even more we can achieve.”

Thermal disengagement technology

Described in scientific publications SN Applied Sciences and the Journal of Cleaner Production, TDT offers an innovative, efficient and sustainable microrecycling technique to separate the materials in complex PLAP waste. The innovative approach recycles the high-quality aluminium at a comparatively lower temperature without smelting. There is no metal loss in this process, which makes the process sustainable for the environment and world reserves of aluminium.

TDT can transform the aluminium into a clean and green metal, allowing it to be extracted in a way that means it can be used as a high-quality material for manufacturing while minimising residual waste.

Professor Sahajwalla explained, “Green steel and green manufacturing are capabilities we have been pioneering for over a decade. The jobs and sustainability revolution our government wants to create as announced in its 2020 Budget can get a boost from some of these sort of existing innovations where industry and researchers are already successfully partnering.

“Using waste-reforming technology can create new supply chains and jobs, especially in regional locations, because it doesn’t have to be large scale nor expensive. That is why I see a future where recycling and manufacturing are aligned, where waste and recycling become part of the manufacturing supply chain, and that is important in this new COVID era where we now highly value ‘sovereign capability’.”

To help align these sectors and create new supply chains, SMaRT has connected an e-waste recycler directly with a steelmaker, enabling undervalued metals and plastics destined for overseas, landfill or incineration to be used as feedstock.

Nespresso also understands the importance of these new ‘green materials’ supply chains and continues to collaborate with SMaRT and its partners to help build more sustainable outcomes.

Image courtesy of UNSW Sustainable Materials Research and Technology (SMaRT) Centre.