Perth-based explorer Sarytogan Graphite (ASX: SGA) has reported a breakthrough in metallurgical testwork being conducted on samples from its namesake graphite deposit in central Kazakhstan.

The company’s German laboratory partner Pro-Graphite GmbH has used low temperature alkaline roasting to improve graphite purities to 99.70% total graphitic carbon (TGC).

An alternative chemical purification process separately achieved 99.70% TGC while a combination of both processes returned 99.87% TGC.

Battery anode specifications

Sarytogan managing director Sean Gregory said the improved grades represent a significant step towards the achievement of battery anode specifications.

“We are thrilled with this breakthrough metallurgical result,” he said.

“The giant high-grade mineral resource at the Sarytogan project is now complemented by a premium micro-crystalline high-purity product [and these] credentials have elevated the project to become a potential answer to the world’s projected battery anode material shortage.”

He said the battery anode strategy would be supported by an uncoated spherical graphite product, which presently trades at more than US$3000 per tonne and is approximately triple the price of traditional flake graphite.

Blend of samples

Pro-Graphite’s testwork involved a blend of samples collected from three holes at Sarytogan’s Northern Graphite Zone and three from the Central Graphite Zone.

The composite sample was subject to the same flotation and grinding steps as used by Perth-based mining services group Independent Metallurgical Operations which recently achieved a premium micro-crystalline sizing of approximately 10 microns.

The graphite purity achieved at the same stage by Pro-Graphite is reported to be similar to IMO’s at 84% TGC, with a slight improvement due to the measurement method.

The flotation concentrate was upgraded by alkaline roasting at a low temperature using caustic soda and a weak sulphuric acid wash to achieve a graphite purity of 99.70% TGC.

It represented an improvement on the 92.1% TGC previously reported in October.

Without alkali roasting, the flotation concentrate was also able to be upgraded by chemical purification to 99.70% TGC.

Identical purity results

Mr Gregory said while identical purity results were achieved by alkaline and chemical purification processes, combining both methods had been “even more effective” with 99.87% TGC achieved so far.

“Pro-Graphite is continuing to optimise the purification process,” he said.

“The residue from the test work will be assayed to assess its mineralogy and devise further process improvements, such as alternative acids, aimed at achieving even high purities.”