Study on the effects of a novel imidazoline siliconophilic collector in the desilication process of magnesite: Separation experiments, adsorption mechanisms, and separation model

This study innovatively introduced heptadecenyl amine ethyl imidazoline quaternary ammonium salt (ODD) as a siliconophilic flotation collector, effectively facilitating the achievement of high-efficiency separation of magnesite from quartz. ODD exhibits unique properties such as high selectivity and environmental friendliness. Through a comprehensive series of experiments, including flotation tests, zeta potential characterization, atomic force microscopy (AFM) imaging, Fourier-transform infrared (FTIR) spectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS), the flotation performance and selective adsorption mechanisms of ODD were thoroughly investigated. The experiments demonstrated that at a pH of 7.00 and an ODD concentration of 40 mg/L, quartz achieved a flotation recovery rate of 95.16 %, while magnesite was only 2.99 %, underscoring the high selectivity of ODD in mineral separation. Zeta potential measurements indicated that ODD exhibits strong adsorption interactions with quartz over magnesite. AFM observations confirmed that ODD forms significant adsorption structures on quartz surfaces, in contrast to weaker interactions with magnesite. FTIR analysis further revealed the robust interactions between ODD and quartz through hydrogen bonds and electrostatic forces, which were significantly diminished on magnesite surfaces. ToF-SIMS analysis provided direct evidence of ODD's selective adsorption on quartz, contributing to a better understanding of the flotation mechanisms involved. This research not only offers a novel approach for the purification of magnesite and effective removal of quartz but also demonstrates the potential of ODD as an eco-friendly collector in mineral processing, potentially advancing a green transformation in the industry. The findings provide a solid theoretical and experimental basis for future industrial applications and innovative development of flotation collectors.