Lithium mining: a three-step process
The EMILI project’s lithium mining process is being developed at the laboratory level. It uses technologies already proven in the mining and industrial world and is based on three stages:
1. Extraction of lithium-bearing granite
The first step in the process is extraction, a traditional mining activity like many others in Europe or around the world. There are several possible mine designs, however Imerys aims to perform this extraction in an essentially underground configuration, in line with its environmental commitments and its commitment to preserving the landscape and natural environments.
2. Concentration of lithium bearing mica and transfer to conversion plant
Once the granite has been extracted, the objective is to isolate the mineral that contains lithium, mica. To do this, it is necessary to crush the rock in order to release the various minerals, then to perform separation steps, using technologies used elsewhere on many Imerys group sites, to collect a lithium bearing mica concentrate.
Once the mica is isolated, or “concentrated”, it must be sent to the conversion unit. Imerys wants to avoid truck transport, to minimize noise and carbon emissions. A hybrid solution for transport by underground pipes and then by rail is therefore envisaged.
For this purpose, mica is mixed with water at the concentration site and then transported by underground pipes to a loading plant near a railway track.
The water is then removed from the concentrate, recycled and returned by piping to the concentration site. The mica is loaded into a train for delivery to the conversion plant.
3. Lithium conversion
The conversion phase consists of extracting the lithium from the lithium bearing mica to produce lithium hydroxide in powder form.
To separate this lithium hydroxide from the other elements, the conversion process studied first of all involves calcination. The calcined product is then leached and purified. The lithium hydroxide is then crystallized to obtain the final product in powder form. It can then be marketed to companies in the electric vehicle battery industry.
