First Graphene Limited (“ASX: FGR” or “the Company”), is pleased to provide an update on the incorporation of PureGRAPH® into rubber compounds for applications in the mining sector.
As reported in March this year, FGR commenced work on the manufacturing of PureGRAPH® powders into long-chain rubber polymers.
To leverage customer interest, FGR concentrated on the compound most commonly used in the mining screen media market, with potential to adapt the findings into other sacrificial wear-liner rubber materials across the industry. The work has been conducted in conjunction with an experienced rubber consultant in Perth and an established rubber processor in Ipoh, Malaysia.
First Graphene Managing Director, Craig McGuckin says the results from the extensive test work undertaken are encouraging.
“The initial work demonstrates a low dosage of PureGRAPH® provides improvements over the base material most commonly used for the mining screen media market,” McGuckin said.
“Further tests will be undertaken with the PureGRAPH® compounded rubber for both mining screen and sacrificial wear media, as this is a large market and one in which we are actively engaged with both suppliers and end users.
“The results so far provide the platform to introduce PureGRAPH® into other compounded rubber materials both in industrial and domestic use.”
FGR engaged an experienced rubber consultant to understand the science associated with the compounds used in the mining screen and wear media markets.
Rubber compounds vary considerably depending on their use. Screening tests were completed on 35 compounds using formulation variations and compounded on a laboratory scale two-roll mill, similar to that in Figure 1.
The two-roll mill allowed for multiple small batches of rubber to be produced with adjusted PureGRAPH® concentration and rubber chemistry. A range of mechanical testing could then be carried out on each batch to evaluate performance and produce the following data displayed in Figure 2.
Figure 2 demonstrates that multiple mechanical improvements can be achieved through low addition rates of graphene using a two-roll mill. This resulted in a better understanding of how certain mechanical properties can be tailored for specific applications through adjustments to the graphene concentration and rubber chemistry.
Upscaling of Test Work using PureGRAPH®
Laboratory testing demonstrated the benefits for numerous graphene enhanced rubber compounds using a two-roll mill.
Laboratory scale equipment does not fully resemble the processing conditions present in full scale commercial rubber compounding, typically carried out in large internal mixers followed by industrial two-roll mills, and so it was important to upscale the laboratory testing to better simulate commercial rubber compounding and demonstrate the benefits of graphene under this environment.
For the commercial scale tests, a control rubber was selected based on industry compounding experience, demonstrating the desired mechanical properties of a typical hard rock screen or wear liner application.
A production scale run of this material was then compounded using the Malaysian partner’s commercial production process line, both with and without the addition of PureGRAPH®. The compounded rubber was then moulded into large prototype parts and test sheets for mechanical testing.
Results from PureGRAPH® enhanced rubber
The following table outlines the improvements achieved from the incorporation of PureGRAPH®20 in the base material used for mining screen or wear media compounds.
The improvement in abrasion resistance (i.e. decrease in abrasion wear over the base material) and tear strength is of particular importance for improved performance and longevity of screen media.
As detailed in Table 1, both abrasion resistance and tear strength can be significantly improved through a low addition rate of PureGRAPH® into the rubber compound.
Client compounded PureGRAPH® enhanced rubber screens are currently in field trials in the mining industry in Western Australia.
Further laboratory test work is underway on additional rubber compounds and processing techniques focussing on improved compound dispersion and fire-retardant applications. Updates will be provided as this work is completed.