Bringing the circular economy to life

CHALLENGE

Australia has a recycling problem. In 2018 when China banned the import of 24 kinds of solid waste, Australia found itself with 619,000 tonnes of recyclable waste a year with no way to process it. Much of this recyclable waste, in particular industrial and e-waste often contains valuable raw materials. However, its heterogenous nature makes it difficult to sort and recycle leading to much of it ending up in landfill. Similarly, tyres contribute a large volume of hard to recycle waste.

RESEARCH

Since 2003 ARC Laureate Prof. Veena Sahajwalla, and her team, have used a multitude of techniques at Microscopy Australia’s UNSW Sydney facility, the Electron Microscope Unit, in over 100 publications, to contributing to the development new and innovative ways of creating valuable materials and products from difficult-to-process waste.

Her first major breakthrough was ‘green steel’, which uses waste rubber tyres and plastics as a green replacement for coal during coking in the steel making process.

She then founded the Sustainable Materials Research and Technology (SMaRT) Centre at UNSW Sydney, home of microrecycling science. There modular ‘Microfactorie technologies‘ are being developed to transform problematic waste materials, such as glass, textiles and plastics, into new materials and products, harnessing value from waste resources. These Microfactories are as small as 50-100 square metres and be located wherever waste is stockpiled. The SMaRT Centre is now supporting a number of industry and community-based organisations to adopt this technology.

In addition to her role as Director the new Waste Hub and the Microrecycling Research Hub, Veena is Director of the NSW Government’s Circular Economy Network (NSW Circular).

The SMaRT centre is working on creating valuable products from hard to recycle materials such as:

• Turning e-waste into valuable alloys, industrial-grade ceramics and 3D printing filaments.
• Turning automotive and other waste into sought-after abrasion- and corrosion-resistant hybrid-steels – read more about this research here.
• Turning mixed glass, which currently can’t be recycled in Australia, into a ceramic and other composite products for use in the built environment as kitchen countertops, and for furniture, tiles and flooring.
• Removing polymers from polymer-laminated aluminium, such as coffee pods, for efficient recovery of high purity aluminium, called Green Aluminium – read more about this research here.
• Turning macadamia shells into high purity silicon carbide and silicon nitride nano-powders, normally created using coal, to strengthen and increase shock resistance of materials.
• Using waste coffee grounds to extract valuable phosphorus from steel-making slag for use as fertiliser in poor soils.
• Turning waste timber, used mattress stuffing and many other textiles into built environment materials and possible use as insulation and acoustic panels.

Scanning electron micrograph from our UNSW Sydney facility showing the microstructure of an ultrahard ceramic coating derived from automotive waste.

Left: Prof. Sahajwalla at the furnace. Right: The cross-sectional microstructure of the ultrahard surface layer pictured above which has been exposed using a focused ion beam microscope.

IMPACT

• recovers and reuses waste as a valuable and renewable resource
• moves us towards a more integrated circular economy where materials are kept in use for as long as possible and kept out of landfill
• generates more sustainable and alignment for the manufacturing and recycling sectors

The ‘green steel’ technology, has been responsible for millions if tyres being ‘recycled’ for use in steel making, reducing the need for coke and coal. It has been commercialised and is undergoing further R&D with Newcastle-based, global steel maker MolyCop. The process has since been deployed in two domestic and five international sites (in five different countries).

Industry collaborations also include:

• • Mirvac – As part of its Marrickville residential development, Marrick & Co, the first One Planet Living (OPL) community in NSW, Mirvac sought to highlight the benefits of using recycled waste in the home environment.
  • Hunter’s Hill Council – Supported by local sporting groups and schools, the Council collected old uniforms and the SMaRT Centre used these in its Green Ceramics Microfactorie to reform them into ceramic tiles that were fitted to an island bench in The YARN.
  • Spark Furniture – Partnering with Spark Furniture of South Australia and the ACT Government’s City Renewal Authority, old coffee cups help create a new bin as part of the Canerra City renewal initiative. During part of the COVID-19 lockdown, the collaboration collected single use coffee cups that were transformed into Green Ceramic tiles that form the outer skin of Spark’s newly designed bin enclosure.
  • Resource Recovery Australia – Building an on-site Microfactorie which deconstructs mattresses for scrap steel, process the excess fabric and stuffing to create and sell valuable tile and panel building materials.

Left: Prof. Sahajwalla with caesarstone like material derived from waste glass. Right: furniture in Mirvac display apartments made from the material.