Microrecycling science delivers new ‘material microsurgery’ technique

A new technology that promises to enhance the advanced manufacturing sector in Australia has been developed by the pioneers of ‘microrecycling science’ at UNSW’s Centre for Sustainable Materials Research and Technology (SMaRT).

The novel ‘material microsurgery’ technique developed by Professor Veena Sahajwalla and her team can extract valuable materials and elements from complex waste items and reform them into strengthening layers for steel and other applications.

The technique is outlined in a new scientific paper published by the esteemed American Chemical Society Omega Journal, and complements another new SMaRT Centre paper outlining other developments in their ‘Science of Microrecycling’ paper, published by international journal Materials Today Sustainability. 

The ‘Science of Microrecycling’ paper details the latest breakthroughs by Professor Sahajwalla and her team as they seek to develop new ways to address society’s growing waste and recycling challenges with innovations that can boost manufacturing capability, thus creating jobs and economic prosperity while enhancing environmental and social outcomes.

The SMaRT Centre created the phrase ‘mircorecycling science’ to describe its novel approach to researching innovative approaches and technologies to reform various waste streams into value-added materials and products.

“Australia’s governments have agreed to ban the exporting of glass, plastic, paper and rubber tyres from January 2021, therefore we need to start treating these waste items as the ‘renewable resources’ they really area,” Professor Sahajwalla said. “Ever-increasing population, technological advancement, variable consumption trends, and lack of efficiency in using materials are forcing us near a crisis point in terms of waste management.

“And since COVID-19 has disrupted global supply chains, Australia’s manufacturing has come under sharp focus. The problem of countries now being affected by unreliable global supply chains for certain materials and goods has sparked questions around how to produce the goods they need. We are scientifically developing new technologies to not reform complex waste items into new, value-added materials to help address this ‘sovereign capability’ issue, but to do so through decentralised manufacturing.

“A key challenge is that existing, centralised recycling and waste treatment methods at scale often just turn things like PET bottles back into PET bottles. What we need is a recycling and manufacturing system that can innovate to reform waste for more diverse and value-added end uses. Recyclers traditionally haven’t seen themselves as manufacturers and manufacturers haven’t seen themselves as recyclers, but we need them to. So, if we accept that we need plastic and want to keep it out of landfill, we need a system that treats it as a renewable resource.”

Green materials and products

‘Material microsurgery’ is the latest innovative technique from the SMaRT Centre which has pioneered the technological concept of Microfactories® to reform different waste streams that mostly end up in landfill or stockpiles by turning them into value-added ‘green' materials and products, thus able to revolutionise the recycling and manufacturing sectors.

Material microsurgery uses the foundational selective thermal transformation techniques developed in the microrecycling science by the SMaRT Centre to extract from electronic waste valuable core elements that can be used in a novel way as a high-performance hybrid layer to improve performance of the surface of steel. This means that regular steel can be enhanced to have a ‘super surface’ via the modification.

Veena Sahajwalla in a section of the Microfactorie. Photo: Anna Kucera

This method could be a suitable alternative to conventional surface coatings and reduce the burden on raw material feedstocks. In the material microsurgery study, glass and plastic from spent computer monitors and copper from waste printed circuit boards were used to produce a hybrid thin film layer on a steel substrate to provide a protective layer over the base material at the microscale to alter the overall performance of the material.

This high-performance advanced material is a hybrid layer chemically bonded in situ on steel to produce a super surface with enhanced mechanical properties compared to the uncoated steel.

Material microsurgery

“We use the term ‘material microsurgery’ because we were inspired by the processes medical surgeons use in microsurgery where they apply targeted and selective solutions to problems,” Professor Sahajwalla said. “Existing waste and recycling technology doesn’t do this for our traditional waste treatments. We need to step up to do the things that were thought unimaginable for waste management so it can be cutting edge.”

And in the ‘Science of Microrecycling’ paper, Professor Sahajwalla and her team outline the latest science behind their Microfactorie technologies that use various, discreet modules to transform problematic waste materials, such as glass, textiles and plastics, into new value-added materials and products such as engineered green ceramics for the built environment and plastic filament as a renewable resource for 3D printing. This modular technology is capable of harnessing value from our waste resources to deliver high-value materials and products.

The SMaRT Centre now houses various Microfactories and the material microsurgery technique is the latest innovation that holds promise to help treat our waste as a renewable resource to produce green materials and products that otherwise require virgin resources.

“COVID has unearthed the weaknesses in our current way forward to meet these challenges but we can start a whole new ‘green materials’ movement where we use waste as renewable resources for decentralised manufacturing to supercharge our economy which is going into the biggest recession and depression since the 1930s,” Professor Sahajwalla said.

Background to microrecycling science and Microfactories

In addition to the green ceramics Microfactorie technology as described above, another Microfactorie module can reform plastics into high-value renewable resources for use as filament to 3D print.

An earlier innovation developed by Professor Sahajwalla and her team was polymer injection technology (PIT), known as ‘green steel’, which uses old rubber tyres in steelmaking as an alternative to coke and coal. The concept of PIT was developed by Professor Sahajwalla between 2003 and 2005.

Professor Sahajwalla knew from lab-scale tests that significant efficiencies (with flow-on environmental benefits) could be derived from her novel process.

New work is also underway using Microfactorie technology on developing additional alternatives to coke and coal.

Numerous collaborations with industry are underway to continue to test and use in commercial settings the various products being developed and made at the UNSW SMaRT Centre Microfactories.

Links to more details

• CPA In The Black: How inventor Veena Sahajwalla is revolutionising recycling science 
• Furnishings from waste in the built environment
• Mirvac contributing to a circular economy 
• Technologies and tools for a manufacturing transformation 

Audio, B roll and more content available via Technology available to achieve COAG waste crisis goals.