Evolution Energy Minerals (ASX: EV1, FSE: P77) is pleased to report positive results from testwork aimed at the production of uncoated and coated spherical graphite from thermally purified graphite from the company’s Chilalo Graphite Project in Tanzania.
The testwork builds upon earlier tests that confirmed thermal purification could produce an ultra-high purity of 99.9995 wt% C prior to milling and shaping.
Evolution is pleased to report the outstanding spheroidisation and electrochemical performance of our Chilalo flake graphite,” Managing Director, Phil Hoskins, said.
“Our inverted process flow sheet has achieved significantly higher yield into usable spherical graphite compared to traditional particle shaping circuits. Following the application of our proprietary surface coatings to spheroidised particles, the resulting coated spherical graphite exceeds the specifications of leading EV battery manufacturers.
“Preliminary battery testing has demonstrated electrochemical performance that is essentially as good as it gets for coated spherical graphite, due primarily to the unique properties of Chilalo flake graphite.
“These factors point toward the suitability of Chilalo graphite to producing the highest quality lithium-ion battery anode materials that attract premium prices and to Evolution’s downstream processing technology providing a leading cost and margin position in the industry.”
Testwork Stages
Evolution is working with a US technology partner, an established manufacturer of advanced battery materials and experienced graphite supplier to the battery industry, on a series of tests to determine the suitability of Chilalo’s fines product for downstream processing into higher value battery anode materials.
The initial testwork stage established that graphite from Chilalo contained extremely low amounts of Molybdenum and Boron. Elemental analysis of impurities in Chilalo’s 95% C flake graphite fines concentrate identified extremely low levels of naturally occurring Molybdenum and Boron, opening the pathway to premium performance batteries (where extremely low concentrations of Molybdenum are a pre-requisite), and nuclear-grade graphite (which require naturally low levels of Boron).
The second testwork stage involved thermal purification of the graphite to achieve battery grade (>99.95% C). This purification resulted in an extremely high purity of 99.9995% C, which exceeds the purity requirements of both the battery and the very high value nuclear sector.
Evolution adopted an ‘inverted’ flow sheet whereby the purification step is undertaken prior to milling and shaping into spheroids, which is the opposite of the traditional approach. This current testwork stage took the 99.9995% C thermally purified graphite and undertook a process of shaping and milling, otherwise known as spheroidisation.
Traditional flow sheets that mill and shape first generally have a yield of ~40%, with the 60% rejected suitable only for low value by-products. Evolution’s process has resulted in significantly higher yields, with the rejected material potentially being suitable for high-value by-product applications due to its very high purity.
Following spheroidisation, the uncoated spheroidal material was then subjected to a proprietary coating process with soft carbon, with the resulting carbon coated spherical graphite having properties that meets the specification of some of the leading EV battery producers in the world.
Next steps
Long-term cycle testwork is ongoing, with further results expected in the coming weeks. The Company also expects to finalise the demonstration projects on the non-spherical by-product, aiming to produce battery cathode conductivity enhancement materials and premium performance electrically conducting coatings.