Sarytogan Graphite Ltd (ASX:SGA) has made another key breakthrough in testing of Sarytogan Graphite with the Equivalent Boron Content (EBC) being well under the maximum specification for the highest purity nuclear graphite for use in nuclear reactors.
Graphite from the Sarytogan deposit in Kazakhstan had previously been purified above ‘five nines’ purity but has now achieved even greater potential value after assaying at 1.1 parts per million (ppm) EBC, under the maximum specification of 2 ppm.
“Super-premium dimension”
Sarytogan managing director Sean Gregory said: “Sarytogan Five Nines Graphite has now been independently assayed to meet the EBC specification required for use in nuclear reactors.
"This adds a super-premium dimension to Sarytogan Graphite product offering for uses in traditional industrial, lithium-ion battery, primary battery and advanced industrial markets.”
About the tests
The bulk flotation graphite concentrate produced in Australia was purified by the company's American technology partner to 2.2kg at 99.9991% C (carbon), measured by LOI determination. One 570g sub-sample, purified with a specific set of process parameters, assayed 99.9992% C.
A sample of Sarytogan ‘Five Nines Graphite’ was then sent to another independent laboratory in the USA for assay by Glow Discharge Mass Spectrometer.
This assay covered the full suite of 26 elements required to calculate EBC under the American Society for Testing and Materials (ASTM) International Standard Specification for Isotropic and Near-isotropic Nuclear Graphites, D7219-19 with the result determined to be 1.1 ppm EBC.
Indispensable in reactors
Sarytogan is buoyed by this result as graphite has been an indispensable part of the nuclear fission reactor since its invention in the late 1930s. Its primary use is as the moderator surrounding the uranium fuel rods to slow down the neutrons released during fission so that a continuous fission chain reaction can be maintained.
To be suitable for use as a moderator in nuclear reactors, graphite should be a fine powder at very high purity of 99.995% C minimum.
Impurities of elements other than carbon may capture, rather than bounce, the escaping neutrons. The elemental boron (B) has a particularly large neutron capture cross-section which is detrimental to the moderator’s performance.
In addition to boron, another 25 elements can also have a lesser effect on the performance of the graphite moderator and assays of those elements are factored and totalled to give an EBC.
High-purity graphite is also used in the nuclear industry in applications other than the moderator including yarns, seals, lubricants, coatings, foils and reflective materials.
Growing market
These nuclear applications adds another layer to Sarytogan’s product strategy to place as many units of carbon into as many markets as possible.
The global market for nuclear graphite is currently about 60,000 tonnes per annum and is set to grow with the renewed worldwide investment in nuclear power. Graphite used as nuclear moderators sells at prices higher than US$25,000 per tonne, a significant premium to graphite used in lithium-ion batteries.
Sarytogan product mix
Sarytogan plans to produce three product types in approximately equal proportions.
The upstream beneficiation using grinding and flotation is planned to produce microcrystalline graphite at 80-85% C at the mine site.
Some of the micro-crystalline graphite will be diverted for sale into traditional industrial uses such as refractories, crucibles, foundries, friction parts, pencils and lubricants.
The rest of the flotation concentrate is planned to be processed downstream by thermal purification and spheroidization to Uncoated Spherical Purified Graphite (USPG) for lithium-ion battery anodes and Ultra High Purity Fines (UHPF) for advanced industrial uses, including nuclear.
Other tests
Long-cycle battery testing is continuing on coin cell batteries made with Sarytogan USPG anodes. Short-cycle testing results were previously reported and long-cycle results will be reported imminently.
Coin Cell batteries have also been manufactured with Sarytogan CSPG anodes and battery testing is well advanced with initial results to be reported shortly.
These results are key inputs into a pre-feasibility study which is on track to be completed during the third quarter of 2024.