Results from leach test-work on bulk (non-beneficiated) samples in 2019 indicated lithium recoveries of more than 95% with short residence times using sulphuric acid (H2SO4) leach at moderate temperatures and atmospheric pressure, with potential to reduce acid consumption through the recycling of leachate.
Lithium content increased
In August 2020 Jindalee announced that beneficiation of McDermitt ore via attrition scrubbing at 20% solids had increased the lithium content in the <0.01mm fraction by more than 50% while reducing carbonate and analcime.
The latest attrition scrubbing test-work, designed to produce a beneficiated sample for leaching experiments, increased the lithium content in the <0.01mm fraction by 60.9%.
Furthermore, initial leaching experiments on beneficiated samples demonstrated lithium extraction rates of 94-97% with 26% less acid consumed per lithium unit than for previous similar experiments on non-beneficiated ore.
The test-work also indicated that the residue remaining after leaching is relatively benign, comprising quartz, feldspar and gypsum.
Experiments to further optimise lithium recoveries and reduce acid consumption are continuing.
Assay laboratories in the United States are experiencing significant delays due to the uplift of exploration activity and ongoing complications related to COVID-19, with results from the final five drill holes completed at McDermitt in December 2020 now expected in mid-March 2021.