Green360 Technologies Limited (ASX:GT3) has heralded a major breakthrough in the development of its proprietary low-carbon cement, successfully transforming red mud – a hazardous byproduct of alumina production – into a safe, high-performance construction material
The company announced on May 29 that recent lab testing confirmed its red mud-kaolin cement blend meets international safety standards for leaching behaviour and delivers competitive strength performance when substituting 30% of Portland cement in standard mortar mixes.
The breakthrough paves the way for commercial-scale validation, which Green360 will undertake in collaboration with precast concrete manufacturer PERMAcast. The joint venture aims to test and demonstrate the red mud-kaolin blends across a range of precast concrete product lines, supporting the company’s push for near-term commercial adoption.
“The results we have achieved from these low-carbon cement formulations made with red mud, an industrial byproduct that is otherwise waste, and kaolin are extremely encouraging,” Green360 executive chairman Aaron Banks said.
“We’ve not only addressed a significant environmental challenge by repurposing red mud – a major industrial byproduct – but also unlocked its commercial potential in sustainable construction,” he added. “The results we’ve achieved in both environmental safety and strength properties validate our vision for a circular, low-carbon materials future.”
Turning red mud green
Red mud, a caustic residue left behind after refining bauxite into alumina, poses significant disposal challenges for the mining industry, with each tonne of alumina produced generating as much as one and a half tonnes of red mud.
Green360’s proprietary treatment process, which blends red mud with kaolin, has demonstrated a 95% reduction in chromium leachate and complete immobilisation of uranium and thorium – elements that have traditionally limited red mud’s reuse. The addition of kaolin, a naturally occurring clay material, enhances the chemical stability of the blend and contributes to the cement’s binding properties.
Independent testing confirmed that the treated blend meets EN 12457, a European Standard on leaching commonly used to assess the environmental impact of industrial byproducts. Treated samples recorded chromium levels of 0.023 to 0.026 milligrams per litre (mg/L), well below the 0.5 mg/L inert limit, while uranium and thorium were undetectable.
Commercial-ready performance
In addition to its safety profile, the treated material showed strong mechanical properties. Mortar mixes substituting 30% of Portland cement with the red mud-kaolin blend achieved an average 28-day compressive strength of 30 megapascals (MPa) – more than 85% of the reference mortar’s strength.
Green360 said the results were “encouraging early validation” of the suitability of its formulations for commercial applications, with qualities competitive to traditional products and the potential to reduce emissions.
“Alongside PERMAcast, we are rapidly developing alternatives to traditional Portland cement that still perform to commercial standards and are suitable for real-world applications,” Banks said.
“We look forward to progressing development of our red mud formulations, and to exploring other industrial byproducts that could be used to create a low-cost, high-quality low-carbon cement product.”
Towards widespread adoption
The joint venture with PERMAcast will focus on demonstrating product performance across a range of precast concrete applications, advancing Green360’s commercialisation strategy and its goal of widespread adoption of low-carbon construction materials.
The company’s broader mission is to deliver cost-effective, low-emissions alternatives to traditional cement – one of the most carbon-intensive building materials globally – and to contribute to circular economy solutions within the resources and construction sectors.