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The pilot plant was fed Lepidolite Hill ore from WA continuously from September 12-17, 2016, with around 650kg of lepidolite ore processed at a throughput of 6kg per hour.
Hot commissioning was done beforehand over a one-day run, with the nature of leach liquors and residues evaluated and final adjustments made to plant components in preparation for the continuous operation.
Testing revealed very high plant availability, exceptional lithium extraction, and high-purity lithium solutions for the production of lithium carbonate.
The pilot plant – made up of leaching and impurity removal circuits – produced a purified lithium-containing liquor devoid of impurities.
According to Lithium Australia this purified liquor will be processed to high-purity lithium carbonate in a second pilot campaign in the near future.
The extraction of lithium in the Sileach process exceeded 95% in the leach circuit, which validated the accelerated rate of extraction of lithium achieved in the laboratory test work program.
Performance in the impurity removal circuits was comparable with laboratory test work, subsequently producing a liquor suitable for further processing.
Lithium Australia managing director Adrian Griffin said plant performance could not have been better.
“The results show that exceptional lithium extractions can be achieved without the need for fine grinding, or the production of clean concentrates,” he said.
“The material processed was not subjected to pre-concentration but still achieved outstanding performance with minimal feed preparation, and these are key parameters for processing at low cost.”
Griffin said lower-grade spodumene concentrates from Pilbara Minerals’ Pilgangoora project would be processed in one of the subsequent test runs.
“We are intentionally concentrating on the lower-grade, hard rock products, from which no other processes can recover lithium commercially,” he said.
“With Sileach the successful processing of spodumene from Pilgangoora is the first step of our commercialisation agreement with Pilbara Minerals, aimed at establishing a lithium chemical processing plant in Port Hedland.”
