Study on the performance and mechanism of novel hydroxyl quaternary ammonium collector for separation of quartz from apatite

Efficient utilization of low-grade apatite is crucial for securing a stable supply of phosphate fertilizers, making the research and development of high-efficiency collectors essential for its utilization. This study introduces a novel, eco-friendly hydroxyl quaternary ammonium collector, dodecyl dimethyl hydroxyethyl ammonium bromide (DHDB), for the reverse flotation desilication of apatite. The flotation performance and adsorption mechanism of DHDB were systematically investigated through flotation tests, contact angle tests, Fourier transform infrared spectrometer (FTIR) measurements, and molecular dynamics simulations. The flotation results demonstrated that DHDB exhibited excellent selectivity at lower dosages and across a wide pH range, enabling quick and effective separation of quartz from apatite. Mechanism tests and molecular dynamics simulations indicated that the adsorption of DHDB on minerals was primarily driven by electrostatic interactions and hydrogen bonding. The weak electronegativity of the apatite surface and the steric hindrance of the polar groups from DHDB resulted in the poor adsorption of DHDB on the apatite surface. Additionally, the selective separation of quartz from apatite was primarily due to the significantly lower adsorption energy and capacity of DHDB on apatite compared to quartz.