Selective Adsorption of 2-Hydroxy-3-Naphthalene Hydroxamic Acid on the Surface of Bastnaesite and Calcite

In this study, 2-hydroxy-3-naphthalene hydroxamic acid (NHA) was used as a collector in microflotation experiments. By comparing the flotation performance of NHA with that of sodium oleate (NaOL) and salicylhydroxamic acid (SHA) commonly used in industry, the performance of NHA in the flotation separation of bastnaesite and calcite was studied. Potentiodynamic (zeta) measurements, Fourier transform infrared spectroscopy (FTIR) measurements and X-ray photoelectron spectroscopy (XPS) measurements were used to reveal the interaction mechanism of bastnaesite with NHA. The results of the pure mineral microflotation test showed that when the pH value was 9 and the dosage of NHA was 4.0 × 10−4 mol/L, the recovery of bastnaesite reached 93.5%. A concentrate with a bastnaesite grade of 87.08% was obtained from the flotation test of artificially mixed ore, and the recovery of bastnaesite was 90.83%. The zeta measurements and FTIR experiments showed that NHA adsorbed onto the surface of bastnaesite, which changed the surface state of bastnaesite. XPS testing showed that NHA chemically adsorbed onto the bastnaesite, and Ce3+ formed a chelated structure with −C(OH)=NO−. The hydrophobicity of the surface of bastnaesite was improved, which made it easier for bastnaesite to adhere to the slurry surface by bubbles. At present, most of the domestic methods for recovering fine-grained bastnaesite use flotation recovery. Calcite and other gangue minerals inevitably enter into the concentrate resulting in low-grade REE concentrate.