International Graphite has released the results of purification and electrochemical testing on graphite concentrates produced at its Springdale Graphite Project in Western Australia.
The graphite concentrate micronising, spheroidising and purification test program was conducted in Germany by industry specialists ProGraphite GmbH (ProGraphite). The electrochemical test work was also conducted in Germany, under ProGraphite’s supervision, by a specialist graphite battery testing group.
The graphite concentrate tested came from reserve samples produced from previous beneficiation testwork using drill core samples from Springdale. Purification testwork involved the application of a modified caustic soda roast process at lower temperature than previously applied and with a simplified number of stages.
Optimised tests achieved results ranging from 99.96 per cent Loss On Ignition (LOI) to 99.97 per cent LOI, thereby exceeding the industry standard purity grade of 99.95 per cent and also meeting all the element-specific requirements of major lithium-ion battery and electric vehicle manufacturers.
International Graphic has said that there is considerable scope to further optimise these results.
Electrochemical testwork on the uncoated purified sample of Springdale graphite concentrate achieved near theoretical-specific capacity for a graphite anode in lithium-ion batteries of 372mAh/g.
Battery stress testing over 46 charging/discharging cycles showed Springdale graphite concentrate has very high stability and durability, with the 46th cycle giving a reversible capacity of 368mAh/g. Stress testing over longer cycles will be conducted in the next stage of battery testwork.
International Graphite Technical Director, David Pass, said that the purification results demonstrate the potential for an optimised and simplified purification process to be used as an alternative to the traditional industry standard HF method.
“The electrochemical results are highly encouraging as a first phase sighter test program,” Mr Pass said.
“These results will inform the optimisation of micronisation, spheroidisation and purification testwork and flowsheet development for our planned battery anode facilities.
“To do that, we will be using approximately 115kg of Springdale graphite concentrate that was produced by the bulk concentrate testwork program undertaken in the second half of 2023.”
