Phosphate, a critical material used in fertilizers and emerging lithium iron phosphate (LFP) batteries, faces unique challenges in beneficiation. Direct flotation of phosphate is impractical due to the inefficiency of current reagents, necessitating reverse flotation, which involves processing higher volumes of gangue. This approach increases reagent and water consumption, leads to significant phosphate loss in tailings, and causes environmental issues. For instance, Florida’s phosphate operations have produced over two billion tons of clay waste containing 600 million tons of phosphate and 600 thousand tons of rare earth elements. Reverse flotation also fails to enable the processing of low-grade and secondary phosphate resources.
This study introduces an AI-accelerated first-principles approach to discover selective reagents for direct phosphate flotation. We explore reagents that target subtle differences in the quantum mechanical properties of minerals. Preliminary results indicate that reagents containing carboxylic acid and/or sulfonic acid functional groups exhibit the highest affinity for phosphate mineral surfaces. Furthermore, the presence of dissolved metallic ions such as Mg²⁺ and Al³⁺, commonly released from associated gangue minerals enhances the adsorption of these reagents. These ions significantly alter the surface electronic charge and isoelectric point of the phosphate minerals by influencing the solution ionic strength and the structure of the electrical double layer.