A Fundamental Study on the Selective Flotation Separation of Magnesite and Quartz Using an Eco-Friendly Collector PKO-H: A Performance and Adsorption Mechanism Study

To achieve efficient desilication and improve the grade of magnesite, an environmentally friendly surfactant, cocamidopropyl dimethylamine (PKO-H), was employed as a collector for the flotation separation of magnesite and quartz. The flotation performance and adsorption mechanism of PKO-H was systematically investigated through flotation experiments, Fourier-transform infrared spectroscopy (FTIR), contact angle measurements, zeta potential analysis, and molecular simulations. The flotation results demonstrated that PKO-H exhibited excellent selectivity, achieving a MgO recovery rate of 98.8% and a concentrate grade of 45.7% in artificially mixed mineral samples. Contact angle measurements, FTIR spectra, zeta potential analysis, and molecular simulations revealed that the adsorption of PKO-H on quartz is primarily driven by electrostatic attraction. In contrast, due to electrostatic repulsion, the interaction between PKO-H and magnesite is weak, preventing stable adsorption. This study establishes PKO-H as a sustainable and efficient collector for magnesite beneficiation and provides new insights into interfacial mechanisms for the design of eco-friendly flotation reagents.