Sarytogan Graphite Ltd (ASX:SGA) has taken an important step towards industrial-scale thermal purification with its American laboratory partner successfully manufacturing graphite agglomerates from its Sarytogan Graphite Deposit in central Kazakhstan.
A composite one-kilogram sample of floatation concentrates from several bench-scale flotation tests was shipped from the company’s Australian lab partner to its American lab partner. A binder was added to the graphite and processed to produce the agglomerates.
This is an important step for the scale up of the thermal purification flowsheet option, which has previously achieved ultra-high purity of 99.99% at the benchtop scale.
Bulk concentrates are now being packaged into 3-6 kilogram lots for dispatch by the company’s Australian lab partner to laboratories worldwide for further scale up of purification, demonstration of spheroidization and quantification of battery performance.
Sarytogan managing director Sean Gregory said: “The process development for the Sarytogan Graphite Project has been a truly international effort with valuable input from laboratories in Australia, Germany, Ukraine and now the United States of America.
“This result is focused on the physical properties important for efficient thermal purification at industrial scale. The next step will be to replicate the ultra-high purity result of 99.99% previously achieved on 50 grams of Sarytogan graphite at a larger scale of several kilograms using the bulk concentrate that is now available.”
PFS flowsheet options
Sarytogan also advises that its pre-feasibility study (PFS) is progressing well, and is due to be completed no later than the third quarter of 2024.
The PFS is currently considering two main flowsheet options — chemical purification and thermal purification.
Chemical purification was first tested by one of Sarytogan’s German laboratory partners who achieved up to 99.87% total graphitic carbon (TGC). Thermal purification was tested by its Ukrainian laboratory partner who achieved a remarkable 99.99% TGC, far exceeding the grade specification of 99.95% TGC for battery anodes.
While the company has demonstrated the thermal purification of ultra-fine graphite at the 50 gram scale, the graphite needs to be agglomerated to scale up to an industrial scale.
The company outlined the benefits of thermal purification compared to other purification methods:
- The grade specification for uncoated spherical purified graphite has been comfortably exceeded (99.99% vs 99.95% TGC).
- A high purity (99.99% TGC) fine by-product will be produced for high value specialised markets.
- The optimal thermal reactor size is about 7,000 tonnes per annum, meaning a lower-capital small scale start-up of one module will be possible, with the project’s giant and exceptionally high-grade mineral resource of 229 million tonnes at 28.9% TGC catering for many possible future expansions.
- The off-gas treatment system may be able to crystalize valuable metals for potential byproduct streams.
Sarytogan notes that Kazakhstan is an excellent place to establish a thermal purification plant as low cost of operations will be possible, with skilled labour readily available and lowest quartile power available.
High and medium voltage powerlines run within a few kilometres of the project and traditional power sources are supplemented by renewable energy such as the 50MW solar farm operating only 100km from the project.