Auxiliary collector optimizing foam characteristic and adsorption behavior towards efficient flotation desilication of bauxite

The desiliconization of bauxite through flotation poses challenges due to the limitations of conventional collectors like oleic acid. Hence, there is an urgent need to explore more selective alternatives to enhance efficiency. In this study, sodium dodecyl sulfate (SDS), sodium dodecyl sulfonate (SLS), and benzohydroxamic acid (BHA) are explored as auxiliary collectors with sodium oleate (NaOL) to enhance its efficiency and selectivity. Bench-scale tests reveal that combined collectors exhibit superior flotation efficiency and concentrate quality compared to NaOL alone, both in laboratory settings and actual bauxite ores. Detailed mechanistic insights are provided from both macroscopic and microscopic perspectives. Macroscopic analyses uncover differences in foam and pulp properties among the combined collectors, indicating that the NaOL + BHA system offers moderate foaming performance, stability, and homogeneity, enhancing collection efficacy and selectivity. Microscopic investigations elucidate the adsorption mechanism between combined anionic collectors and mineral surfaces using the quartz crystal microbalance with dissipation (QCM-D) and Fourier transform infrared spectroscopy (FTIR). QCM-D analysis shows that SDS, SLS, and BHA weaken NaOL adsorption on kaolinite surfaces and accelerate reagent desorption, with BHA having the most significant effect. These findings provide valuable insights for optimizing bauxite flotation processes with improved efficiency and selectivity.