Effect of recycled process water on spodumene flotation surface chemistry and collector interactions

This study investigates the surface chemical mechanisms that influence spodumene flotation under fresh and recycled water conditions using advanced Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and quantitative mineralogical analysis. A six-cycle flotation experiment was conducted to simulate progressive water reuse and evaluate its effects on lithium recovery, mineral surface chemistry, and collector performance. Results indicate that water recycling leads to significant accumulation of inorganic ions such as Al3+, Fe3+, and Mg2+, as well as organic reagents, which collectively impart adverse chemical characteristics to the mineral surface environment. These changes correlate with a marked decline in Li2O recovery and flotation efficiency. Surface analyses reveal that the presence of hydrated aluminum and iron species on spodumene grains suppresses collector adsorption, while elevated organic content and collector accumulation render the mineral surfaces hydrophilic, thereby hindering bubble–particle attachment and reducing flotation performance. The study demonstrates the importance of targeted water treatment to manage organic and inorganic buildup and preserve flotation selectivity. The findings provide mechanistic insight essential for optimizing lithium beneficiation under water-limited and environmentally regulated operations.