A new perspective on flotation performance of different particle sizes spodumene in NaOL/DDA: Foam properties and underlying mechanisms

Flotation is a technology that utilizes the differences in hydrophobicity of mineral surfaces to selectively adsorb mineral particles onto bubble surfaces. While traditional research predominantly focuses on mineral-reagent adsorption mechanisms, the role of the foam phase in the flotation process remains insufficiently investigated, particularly in mixed collector systems. In this study, the flotation performance of spodumene with different particle sizes in the NaOL/DDA mixed system was investigated from the perspective of foam properties. Flotation experiments on spodumene with different particle sizes demonstrated higher recovery for intermediate particle size; however, the adsorption heat and adsorption capacity of the agents on the surface of its mineral particles are not the highest. This suggests that the flotation performance of minerals with different particle sizes cannot be fully explained by reagent adsorption mechanisms alone. The results of two-phase foam properties analysis revealed that increasing the DDA proportion in the NaOL/DDA mixed system progressively decreased foaming capacity and foam stability. The results of three-phase foam properties analysis demonstrated that intermediate particle size resulted in significantly enhanced foam stability, consistent with observed flotation performance trends. Through zeta potential measurements, optical microscopy observations, and viscosity measurements, the mechanism of foam stability was studied. It was found that the distribution of surface charges on the bubbles regulated the stability of the foams. Electrostatic interactions not only control the flow rate of the liquid layer, but also indirectly regulate the adhesion of particles and bubbles, thereby affecting the flotation effect of minerals. This investigation provides a novel perspective on interpreting flotation phenomena in mixed collector systems.