High-efficiency reverse flotation separation of magnesite from quartz using a novel collector, N-[3-(Isodecyloxy)propyl]propane-1,3-diamine: Mechanistic Insights into surface selective adsorption

This study introduces N-[3-(Isodecyloxy)propyl]propane-1,3-diamine (IOPDA), a novel cationic surfactant, as a collector in the reverse flotation desilication of magnesite. It systematically evaluates IOPDA’s selective collecting performance in the flotation separation of magnesite from quartz. Single-mineral and artificial mixed mineral flotation experiments were conducted at pH 6.0 and an IOPDA concentration of 80 mg/L, where results showed significant improvements in flotation separation efficiency. The final concentrate achieved an MgO grade of 46.55 %, SiO2 grade of 1.97 %, and a quartz removal rate of 92.51 %. Compared to the conventional Dodecylamine (DDA), the flotation Selectivity Index (SI) and Separation Efficiency (SE) under IOPDA conditions were notably superior, demonstrating its enhanced selective collecting ability. To elucidate the selective adsorption mechanism of IOPDA, advanced techniques—such as contact angle measurements, Zeta potential testing, FTIR, XPS, AFM, and TOF-SIMS—were employed to analyze adsorption on magnesite and quartz surfaces. The study found that IOPDA preferentially adsorbs on the oxygen sites of quartz through electrostatic interactions and hydrogen bonding, while its adsorption on magnesite is weaker. This selective adsorption enhances the wettability difference between the minerals, facilitating highly efficient flotation separation.