Research & Development

MétAmpère have invested heavily in metallurgical testwork and process design and are world leaders in recovery of lithium from micas, such as those we have discovered in Cornwall. Our work on lithium micas began in 2014 and on Cornish micas in 2016, and continues today at our sample preparation laboratory in Roche, Cornwall and at our technology partner’s laboratory in Perth, Western Australia.

Known hard rock lithium occurrences in Cornwall occur within “Zinnwaldite” mica in granites. Zinnwaldite has a complex crystal structure KLiFe2+Al2Si3O10F1.5(OH)0.5 (OH)0.5 and a maximum theoretical grade of 3.42% Li2in the pure mineral. There is currently no lithium production in the world from lithium micas which explains MétAmpères focus on metallurgical research and development.
Hard rock lithium spodumene deposits in Australia are the largest producers in the world. Spodumene occurs as large crystals of relatively high lithium grade material LiAl(Si2O6with a less complex structure than lithium mica and theoretical Li2grade of 8.035% in the pure mineral. Seven mines in Western Australia use floatation to produce a spodumene concentrate of +6% Li which is shipped to processors in China. Recovery of Lithium to concentrate using floatation is however low, typically only 60% to 70%. The high grade of spodumene concentrate and availability of the Chinese market has however enabled Australian miners to rapidly develop and expand their lithium production.

To compete with spodumene, production of lithium from micas requires an unique and efficient physical beneficiation process to produce a concentrate with high recovery followed by environmentally friendly alkaline leach and purification. There are currently no refiners globally who can process Zinnwaldite concentrate, and so a complete plant from mine, to beneficiation, to refining will be needed in Cornwall.

MétAmpère’s engineers have successfully beneficiated Cornish micas using our unique process to produce a +4% Li Lithium concentrate with recovery over 90%. Note that the grade achieved was higher than the theoretical maximum possible. We have also conducted numerous roast trials producing near battery grade lithium carbonate. Successful metallurgical research and process development is critical to demonstrating the potential for economic recovery of Lithium in Cornwall and much remains to be done.

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Pure Zinnwaldite lithium mica extracted from Cornish lithium granite by MétAmpère 2018 grading 34,500 ppm Li2O
Thin Section microscopy of intergrown polylithionite crystals within Cornish lithium mica
QEM Liberation Analysis - Camborne School of Mines (for MétAmpère) Sample - Milled Cornish Lithium Mica Granite
Thin Section Anayslis Relationship of Muscovite, Polylithionite & Feldspar