Imerys, a global leader in mineral-based specialty solutions, and British Lithium, a private company having developed a processing route to produce battery-grade lithium carbonate from mica in Cornish granite, (earlier post) have formed a joint venture with the objective of creating the United Kingdom’s first integrated producer of battery-grade lithium carbonate.

Imerys contributes its lithium mineral resources, land and infrastructure for an 80% stake in the joint venture, while British Lithium brings its bespoke lithium processing technology, its technical team and its lithium pilot plant for the remaining 20%. The proposed development will include a quarry, a beneficiation plant and a conversion unit co-located on Imerys’ brownfield site to produce high-purity lithium.

British Lithium pilot plant.

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Since 2017, British Lithium has carried out drilling and exploration on Imerys-owned land in Cornwall and developed a unique process and pilot plant to produce battery-grade lithium carbonate. It received financial support from Innovate UK, UK’s national innovation agency, and the Automotive Transformation Fund, a funding program to support the electrification of vehicles and their supply chains in the UK.

Following drilling and resource definition, inferred mineral resources are estimated at 161 million tonnes at a grade of 0.54% lithium oxide. These resources give sufficient confidence to target a life-of-mine exceeding 30 years at a production rate of 20,000 tonnes of lithium carbonate equivalent per year, potentially enough to equip 500,000 electrical vehicles per year, by the end of the decade, meeting roughly two-thirds of Britain’s estimated battery demand by 2030 when all UK car manufacturers convert to electric vehicles.

The partnership will benefit from Imerys’ existing mining footprint in Cornwall, its experienced teams, and solid infrastructure, as well as its lithium expertise developed through its EMILI (Exploitation de MIca Lithinifère par Imerys) project in France—expected to be one of the largest lithium extraction projects in Europe. EMILI, launched in 2022, is also using lithium-bearing granite as its source mineral.

The Cornwall mine will adhere to the highest social and environmental standards and follow the IRMA Standard—the most demanding global benchmark for responsible mining.

The transaction has been approved by the UK Government, under the National Security Investment Act protocol. This venture will reduce the UK’s and Europe’s dependence on critical raw materials imports, thus contributing to the achievement of the European and British climate change targets and the creation of the first fully integrated regional electrical vehicle value chain.

The combination of the Cornwall project and the EMILI project in France would make Imerys the largest integrated lithium producer in Europe, representing more than 20% of the announced European lithium output by 2030. EMILI, with a 25-year life-of-mine, is targeting production of 34,000 tonnes per year of lithium hydroxide, to equip approximately 700,000 EVs per year,

Today, Imerys Group employs 1,100 people across the UK, of which 830 are located in Cornwall, including five world-class open-pit mine sites in Cornwall and Devon. The project will also build upon British Lithium’s entrepreneurial spirit and committed team.

British Lithium was the first company to discover a sizable lithium deposit in the UK, the first to develop a novel, environmentally friendly process for extracting lithium and the first to produce battery grade lithium from Cornish granite.

British Lithium’s processing engineers have successfully beneficiated Cornish micas to produce a lithium concentrate grading in excess of 1.2% Li with a Li recovery of more than 90%. Alongside the mineral beneficiation, the company has also conducted numerous low-temperature calcination trials to mobilize Li as well as subsequent leaching and precipitation tests to produce battery-grade lithium carbonate.

Mineral background. Known hard rock lithium occurrences in Cornwall occur within Zinnwaldite mica in granites. Zinnwaldite has a complex crystal structure KLiFe²⁺Al₂Si₃O₁₀F_1.5(OH)_0.5 and a maximum theoretical grade of 3.42% Li₂O in the pure mineral.

Lithium spodumene deposits in Australia are the world’s largest source of hard rock lithium. 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. Mines in Western Australia use floatation to produce a spodumene concentrate of +6% Li which is shipped to refineries in China. Recovery rates of lithium to concentrate using floatation are however low, typically only 60% to 70%. The high grade of spodumene concentrate and availability of the Chinese market has enabled Australian miners to rapidly develop and expand their lithium production, British Lithium notes.

To compete with spodumene, production of lithium from micas requires a unique and highly efficient physical beneficiation process to produce a concentrate with high recovery followed by environmentally friendly alkaline leach and purification.