Anson Resources Ltd (ASX:ASN) has updated results released last week when it successfully conducted test-work at a third-party laboratory using an alternate Direct Lithium Extraction (DLE) technology.
DLE technology uses physical or chemical selective processes to remove lithium from brines while leaving other components in the brine.
As Proactive reported last week, initial test work at the new laboratory improved the expected lithium recovery rate in the first stage of the extraction process to 90%, an increase of 10% from previous test work results.
Further improvement
This new test-work has further improved the estimated lithium recovery rate in the first stage of the extraction process to 91.5%.
Anson is developing its flagship Paradox Basin Brine Project in southern Utah in the US for the recovery of valuable chemicals from a unique salt brine resource. It is focused on the discovery, acquisition and development of natural resources that will meet the demand from rapidly growing new energy and technology markets.
As part of its continual improvement agenda, Anson has continued to test several alternative DLE technologies over the past two years, with the aim of improving operational and economic performance, as well as taking into account Environmental, Social & Governance (ESG) considerations.
Test-work ongoing
Anson began its initial test-work in February this year, utilising 50 litres of previously extracted Clastic Zone 31 brine from the Long Canyon No 2 well, within the Paradox project.
After confirming its process worked, Anson repeated the testing on a small-scale pilot plant test using 4,000 litres of freshly extracted brine from Clastic Zone 31.
The average head grade for the 4,000 litres brine was tested to be 200ppm Li.
Anson sought the fresh brine sample as it believed it would more closely replicate the characteristics of the future production brine, than brine that had been in storage: prolonged storage of the brine in tanks has resulted in precipitation of the minerals.
Why Long Canyon?
The Long Canyon No 2 well is approximately 1.3 kilometres from Anson’s planned production wells.
It is also only 100 metres from Robert’s Rupture, a geological feature where extensive fracturing has occurred in the subterranean rock resulting in higher pressure allowing supersaturated brine to flow to surface under its own pressure.
Given its location, Anson felt the Long Canyon No 2 well was the best option for the collection of the most suitable brine for the planned test work.
Extraction process
The brine sample was collected in June 2021 using 'wireline' acquisition. Anson had previously installed special plugs in the well which allows future extraction to be conducted quickly and at lower cost as 'workover' rigs are not required.
To evacuate the tubing to ensure no contamination, 45 barrels of brine was initially allowed to flow under its own pressure from Clastic 31 at a depth of 6,260 into the on-site sump.
Anson extracted a total of 126 barrels (20,000 litres) from the well. Four totes (approximately 4,000 litres) were filled for DLE extraction test work at a laboratory in Utah and an additional 40 litres provided to TETRA for tests.
The remaining approximately 16,000 litres of brine were transported by tanker into storage tanks previously installed by Anson at the Cane Creek 32-1 well site.
An additional 1,000 litres was provided to TETRA for further test-work as part of the work being conducted under a Memorandum of Understanding for collaboration in the development of the Paradox project.
Prior to starting the test-work program using the alternative DLE technology, the brine was assayed by a third-party accredited laboratory for lithium content. The brine was then added to the pilot plant columns containing the DLE extraction resin/media and circulated for six hours.
Once completed the lithium laden resin/media was washed off using water.
After washing was completed, Anson found the estimated recovery rate of 91.5%, meaning an estimated 91.5% of the contained lithium in the brine was recovered into the washed solution.
In some cycles, the lithium recovery rates were above 100% which is expected to have been caused by some lithium remaining on the resin/media in previous cycles.