An in-depth exploration of the impact of novel collector HPDDA on the low-temperature flotation behavior of bastnaesite and quantum chemical calculation

Abstract

Traditional cationic collectors commonly suffer from drawbacks such as poor solubility and low-temperature resistance, which impede the effectiveness of flotation. Hence, this study designed and synthesised a novel collectors, 2-Hydroxypropane-1,3-bis(dodecyl dimethyl ammonium) bromide (HPDDA), tailored for low-temperature flotation of bastnaesite. The positive charges of the surface molecular electrostatic potential (ESP) of HPDDA concentrate near the two quaternary ammonium groups, with minimal points also appearing between the two N atoms. Near the quaternary ammonium groups, weak van der Waals (vdW) and spatial hindrance occur due to the abundance of polar groups. The Krafft point test reveal that the Krafft point of HPDDA was below 0 °C, significantly higher than that of DDA. HPDDA exhibited excellent pH adaptability and cold resistance, demonstrating outstanding selective capturing capability for bastnaesite even at low temperatures, thereby enabling the separation of bastnaesite from calcite. Analysis through various detection methods such as zeta potential, Fourier transform infrared (FT-IR), contact angle measurement, and X-ray photoelectron spectroscopy (XPS) elucidates the selective adsorption mechanism of HPDDA on the surface of bastnaesite, attributing it to the differences in surface electrification and other properties between bastnaesite and calcite. This work provides new collector and theoretical guidance for solving the low-temperature flotation of bastnaesite.