Green360 Technologies Expands MKX Platform with Silica Fume Replacement

Green360 Technologies (ASX: GT3) has developed MKX Ultra Fine, a second commercial metakaolin product designed as a direct replacement for silica fume in high-strength concrete applications.

Independent testing by the University of Melbourne confirmed MKX Ultra Fine could deliver comparable concrete strength to industry-standard silica fume when used as a one-for-one replacement.

Green360 has produced the material at commercial scale and major concrete suppliers are now trialling it as part of the group’s broader push into supplementary cementitious materials (SCMs).

The product expands the MKX platform beyond replacement markets for fly ash and slag into the higher-value silica fume segment, where domestic supply has declined in recent years.

High-Strength Concrete

MKX Ultra Fine has been designed for high-strength concrete, where silica fume is commonly used to improve performance in infrastructure, precast, and other demanding applications.

The University of Melbourne testing replicated approved mix designs of between 60 megapascals (MPa) and 70MPa, substituting silica fume with MKX Ultra Fine on an equal-quantity basis.

All tested mix designs incorporating MKX Ultra Fine as a total silica fume replacement achieved 24-hour strength of 20MPa or above.

That result exceeds the 15MPa minimum required in many precast applications to support de-moulding, lifting and efficient manufacturing.

SCM Supply Pressure

Green360 has positioned MKX as a response to tightening supply of traditional SCMs used by concrete producers to improve durability and reduce Portland cement content.

Fly ash supply is declining as coal-fired power stations close, while blast furnace slag availability is being affected by changes in steelmaking technology.

Silica fume, which is produced as a by-product of silicon metal production, commands a significant premium to Portland cement and remains critical in high-strength concrete.

Green360 expects purpose-made metakaolin products to become increasingly important as concrete producers seek scalable and locally produced alternatives to shrinking by-product supply chains.

Dual Commercial Pathway

The MKX suite now comprises MKX Calcined Clay and MKX Ultra Fine.

MKX Calcined Clay, previously known as Eco-Clay, has been designed to replace fly ash and slag, while MKX Ultra Fine targets silica fume replacement.

Both products are produced at Green360’s Pittong kaolin operations in Victoria before calcination under a toll treatment agreement with Calix Limited (ASX: CXL).

Green360 recently entered a non-binding memorandum of understanding with Holcim (Australia) for the supply of up to 4,800 tonnes per annum of MKX Calcined Clay, and expects to formalise that agreement in the coming month.

Broader Industry Role

Executive chair Aaron Banks said SCMs played a much broader role in modern concrete than simply reducing carbon emissions.

“SCMs improve strength, reduce cracking, lower permeability, and dramatically increase the lifespan of concrete exposed to harsh environments,” he said.

“In many of the world’s most durable bridges, tunnels, ports, dams, and high-rise buildings, SCMs are not optional extras—they are fundamental to performance.”

Mr Banks said the concrete industry faced a structural supply challenge as the industries that produce fly ash, slag and silica fume continue to change and, in many instances, disappear.

“The industry’s future will belong to scalable, reliable SCM alternatives, and that is precisely the role MKX is designed to fill.”