Suvo Strategic Minerals Ltd (ASX:SUV) reports that a second round of laboratory scale test work has successfully created a metakaolin and fly-ash geopolymer concrete formulation, showcasing a reduction in greenhouse gas (GHG) emissions when compared to production of ordinary portland cement.
Geopolymer concrete is a low emission, environmentally friendlier alternative to traditional concrete made with ordinary portland cement. It is produced by chemically reacting aluminate and silicate-bearing materials with caustic activators like metakaolin, fly ash, ground blast furnace slag and other waste-derived components.
As fly ash is a waste derived product, the geopolymer concrete formulation from this round of testing — an equal part formulation of one part metakaolin for every one part fly-ash — has the ability to significantly reduce the per unit cost of production.
Second round trials success
This second round of trials with Murdoch University, using metakaolin from the company's Gabbin deposit, focused on the potential of creating a geopolymer cement that included fly-ash, a waste derived material, sourced from a power station in Collie, Western Australia.
This geopolymer concrete formulation used a 1-for-1 ratio of metakaolin to fly-ash. When using 100% metakaolin in a geopolymer concrete formulation a 50% reduction in GHG emissions can be achieved.
This new formulation further reduces the GHG footprint as it halves the usage of metakaolin and includes the fly-ash waste product whose emissions are already attributed to the coal burning process. Furthermore, fly-ash is traded at a significantly lower price when compared to metakaolin which reduces the cost base of production of this geopolymer concrete.
Murdoch’s geopolymer cement laboratory ran two tests comprising five samples in each. The first five samples returned an average compressive strength test of 16 million pascals (MPa).
In the second round of tests, the sodium silicate activator was increased by 5% and it returned circa 70% increase in strength to 27MPa. Data collected confirmed that by optimising the formulation ratios further, higher compressive strengths can potentially be achieved.
The company outlined some examples of ‘everyday’ concrete products with a compressive strength of less than 25MPa, such as post and rail retaining wall systems, retaining wall blocks, pavers, culverts, soak wells and single-story house slabs.
A critical piece of work
Suvo non-executive chairman Aaron Banks said: “The outcome of this round of testing was a critical piece of work for the company and it demonstrates that we can combine waste materials within our formulations.
“This potentially achieves two important outcomes; in that we can halve the use of the precursor material (metakaolin) thereby reducing both the cost base and the GHG emission profile in the concrete manufacturing process.
“By utilising waste by-products we can move further towards creating a circular economy whereby we provide an industrial application for waste derived materials that might otherwise be committed to landfill.
“The company used its Gabbin metakaolin in these trials to compare the results with our previous test results using 100% metakaolin. Based on these successful results with Gabbin metakaolin, the company will look to commence geopolymer concrete lab trials with Pittong kaolin and waste derived materials as this is potentially a quicker pathway to commercialisation.”