European Metals Holdings says Geomet, the developer of the Cinovec lithium project, has approved in principle replacing two planned gas-fired rotary kilns with a single tunnel kiln able to use gas or electric heating. Tests reported on 23 October produced 93.4% lithium recovery after roasting and leaching. The decision is conditional on further contracts and procurement steps, and neither the final heat source nor the detailed kiln specification has been fixed.
The change affects the pyrometallurgical stage planned for the lithium chemical plant at Prunéřov in the Czech Republic. The December 2025 feasibility design called for two rotary kilns operating at approximately 950°C, followed by leaching of the treated concentrate. Geomet proposes a solids temperature around 850°C in the tunnel kiln, based on tests intended to achieve comparable extraction while reducing the heat input required by the process.
Electrical heaters, gas burners or a combination could provide the kiln’s energy. Geomet has not decided which arrangement will be installed, so the design should not be described as an electric plant already committed to renewable power. The company is examining whether electricity associated with project partner ČEZ could be used, alongside the engineering and commercial consequences of that choice.
In a tunnel kiln, prepared material can pass through successive controlled temperature zones, allowing the residence time and exposure profile to be adjusted. The planned process targets solids at 850°C and a circulating gas temperature of about 870–880°C, with the company seeking temperature stability of approximately 10°C. A rotary kiln instead tumbles the feed in a heated rotating vessel, creating different conditions for mixing, heat transfer and contact with the kiln atmosphere.
Geomet wants to limit vitrification, in which part of the roasted material can form a glass-like phase that makes subsequent extraction more difficult. Some sintering may still occur, and milling may be necessary before leaching to obtain an appropriate particle size. Recovery therefore depends on feed preparation, reagents, heating and extraction as a connected process, rather than on furnace temperature alone.
Earlier tests in 2024 reported 93.2% lithium recovery after one hour of roasting at 850°C, matching the cited result from a 950°C rotary kiln process. A second testing programme from the third quarter of 2025 considered representative concentrate, briquette formation, reagent requirements and roast and leach performance. Its reported 93.4% recovery is a test result; it is not evidence of continuous commercial plant output.
At the target 850°C, the second programme found no statistically meaningful recovery difference between 30 and 60 minutes of residence time. That raises the possibility of a shorter heating cycle, although equipment loading and operating conditions still have to be established at a larger scale. The investigators also prepared approximately 1,500 kilograms of kiln charge using commercial briquetting equipment to evaluate how the formed material would tolerate handling and roasting.
Briquetting prepares feed to pass through a controlled heating cycle while preserving the consistency needed for downstream handling. Reagent optimisation can reduce the amount of material that must be heated and subsequently managed as a by-product. The company also tested recycling a mixed-salt stream from the downstream lithium phosphate reactor into the kiln charge, which it says could improve recovery while reducing the volume of salt residue.
Cinovec’s December 2025 feasibility study envisaged annual output of 37,500 tonnes of battery-grade lithium carbonate. The venture is owned through Geomet, with ČEZ holding 51% and European Metals 49%. Its projected output would contribute to the European battery materials supply chain, but production has not begun and the recovery figures are derived from test campaigns rather than from an operating commercial kiln.
A change from rotary to tunnel equipment affects upstream and downstream plant design, including briquetting, material transport, exhaust treatment, gas circulation and access for maintenance. The company reports that preliminary layouts accommodate mixing, preheating, cooling and off-gas equipment within the space previously allocated to the rotary kiln installation. Detailed engineering must still demonstrate that the revised arrangement can meet the required duty while fitting the wider chemical plant.
European Metals expects the lower-temperature route to reduce capital and operating costs, but no final saving has been demonstrated for a built and commissioned facility. Its estimate of avoiding approximately 98,000 tonnes of carbon dioxide annually depends on selecting renewable electric heating instead of the relevant gas-fired arrangement. The project has not yet selected that configuration, so the estimate should not be treated as an achieved emissions reduction.
The company says it does not expect the kiln change to delay the project or impair the environmental impact assessment, and anticipates lower environmental impacts from the revised heating process. Those are the developer’s expectations; permitting authorities must still consider the actual plant design and evidence before making their determinations.
Geomet’s in-principle approval depends on finalising testwork contracts and completing preliminary market consultation under Czech procurement requirements. A further two-car shuttle kiln test is planned from November 2026 to examine residence time, heating, handling, reagent consumption and mechanical design at larger scale. Results from that work will inform equipment specifications and procurement before the tunnel kiln can become part of an approved construction programme.
