Research & Development
British Lithium have invested heavily in ongoing metallurgical testwork and process design and are world leaders in recovery of lithium from micas, such as those we have discovered in Cornwall, see our exploration work. Our work on lithium micas began in 2014 and on Cornish micas in 2016, and continues today at our dedicated laboratory in Roche, Cornwall as well as our technology partner’s laboratory in Perth, Western Australia. British Lithium is the only lithium mine developer in UK to have its own, in-house metallurgical research facilities.
There is NO commercial production of Battery Grade Lithium from these unconventional micas hence the focus on our Research and Development.
Dr Robert Gruar, Head of Innovation talks through all things Lithium Processing with Proactive investor.
INNOVATE UK - £500,000 Research Grant
British Lithium Limited (BLL) has been awarded £500,000 of match grant funding from the UK Government to progress its research and development of hard rock lithium extraction in the St Austell area of Cornwall.
With an application success rate of around 6 per cent, the Innovate UK Smart Grant is a highly sought-after award and winning it is testament to the strength of BLL’s business case.
British Lithium Inhouse Laboratory
Our processing facility in Roche was fully set up in 2020 to process exploration samples. Building on this and an Innovate UK grant, at the end of 2020 and start of 2021 our lab was expanded significantly with a range of equipment for demonstrating our mineral processing approach as well as our chosen lithium refinery route.
Key geological processing equipment includes:
- Core saw for diamond core splitting
- Jaw crusher for crushing material from max. 75mm to a size of 2mm
- Riffle boxes and a rotary sample divider
- Olympus portable X-Ray Fluorescence Analyser
- Pulveriser
- Dust extractor and an Airbench for dust control
- Walk-in oven
- Pycnometry equipment and other ancillaries
The most important pieces of equipment in the mineral processing and lithium refining laboratories are: Mineral beneficiation circuit including various pumps and a water feed and recycling system:
- Screening equipment including a large diameter screen and a range of sieves
- Continuous calcining equipment to mobilise Li in the micas
- Continuous stirred tank reactors including heating and chilling equipment
- Extensive suite of laboratory glassware and other ancillaries for selective precipitation and further lithium refining
- Vacuum filtration, filter presses and oven for sample drying
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Process Metallurgy
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% Li2O in the pure mineral. There is currently no lithium production in the world from lithium micas which explains British Lithiums 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(Si2O6) with a less complex structure than lithium mica and theoretical Li2O grade 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.
British Lithium’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.
British Lithium Processing Endeavors
British Lithium’s processing engineers have successfully beneficiated Cornish micas using our unique process to produce a lithium concentrate grading in excess of 1.2% Li with a Li recovery over 90%. Alongside the mineral beneficiation, BLL have also conducted numerous calcination trials to mobilise Li as well as subsequent leaching and precipitation tests to produce near battery-grade lithium carbonate.
Metallurgical scoping studies on the 10 – 100kg scale have provided confidence in our process route and identified opportunities for further optimisation. These optimisation routes are now being assessed as part of an Innovate UK grant. A 13t bulk sample, taken in December 2020, was processed by Wardell Armstrong to determine grindability, carry out desliming trials and produce feed samples that are now being processed further at our mineral processing and lithium refinery facilities.
Extensive mineralogical analysis carried out by Petrolab has shown the other major minerals within the granite include quartz, feldspars, other micas and in some areas kaolinite (china clay), topaz and apatite. Also found in our deposit are various iron and titanium oxides as well as, locally, cassiterite and copper minerals.
Crucially, the grain size distribution of Zinnwaldite in our Li deposit is relatively coarse. Mica liberation at a coarse size has many advantages, including lower grinding energy requirements, lower losses of minerals to the ‘slimes’ (<10µm) fraction and a lower environmental impact of tailings. British Lithium’s process flowsheet is uniquely positioned to take advantagae of the coarse liberation size to realise these benefits.
To start building a geometallurgical framework, testwork is ongoing to identify the importance of various geological domains within the deposit with regards to process response. We have also identified a number of element relationships that provide indicators of the grindability of ore, beneficiation properties and tailings characteristics. Our standard assay suites have been tailored to determine these relationships and also gain insight into the distribution of penalty elements.