11/06/2025
During conventional mineral processing, significant resources are often lost during the beneficiation phase. Lithium-bearing particles trapped in the gangue can proceed to downstream stages, reducing the efficiency of the entire extraction process. To address this, researchers at TU Delft have developed an Opto-Magnetic Sorting System that significantly enhances the separation of lithium ores. This innovative technology combines precision liquid deposition and magnetic separation techniques, offering an advanced alternative to traditional gravity-based separation methods used in beneficiation circuits.
The process starts with lithium-bearing ores being crushed and sieved, isolating particles in the 2–4 mm size range for the next step – optical sorting. A high-resolution line scan camera captures continuous images of particles on a conveyor belt. These images are processed in real-time using a custom algorithm developed at TU Delft, which is trained to identify lithium-rich particles based on subtle colour differences.
Once identified, the target particles are selectively marked using magnetic powder. This enables the marked lithium-rich particles to be separated efficiently by a downstream magnetic conveyor into a dedicated container.
This innovative beneficiation approach has successfully prevented around 45% of the gangue material from entering the downstream process—nearly three times more efficient than the initially targeted improvement of 15%.
According to the State-of-the-Art [SoA], processing spodumene takes place at high-temperatures [1100oC], with direct implications on the economic viability of the entire process. Researchers at TEC have been investigating an alternative to conventional processes. Their investigation features ball milling and calcination at lower temperatures than the conventional process, using additives when needed for the improvement of the next leaching step.
Ball milling is a mechanical process that induces self-sustaining reactions in many sufficiently exothermic powder mixtures. These exothermic reactions, which release a significant amount of heat, can influence both the microscopic and macroscopic properties of the resulting material. On a microscopic level, the heat generated by the reactions can cause changes in the crystal structure and composition of the material. On a macroscopic level, these changes can affect the material’s overall properties, such as its strength, hardness and reactivity. TECNALIA’s findings show that the combination of the ball milling with additives lower calcination temperatures required [200oC below the SoA] in the pre-treatment process of the samples and, also, allow milder conditions in the next processing phases (leaching).
The process, replicated on lithic mica and lithium phosphate materials, were also successful to achieve good results in the next leaching step.
The furnace used in the calcination pre-treatment by TECNALIA