Hydroxypropyl amine surfactant: A novel flotation collector for efficient separation of scheelite from calcite

•NTIA was formed and first used as a collector for flotation separation of scheelite from calcite.•Got recovery rate of scheelite 96.89% and calcite only 8.68% at pH 7 and NTIA 50 mg/L.•NTIA was adsorbed on scheelite surface by static electricity and hydrogen bonds.•Provided efficient flotation separation of scheelite and calcite without depressant. In this work, N-tetradecyl-isopropanolamine (NTIA) is synthesized and used as a new collector on the flotation separation process of scheelite from calcite to further improve the efficiency of the selective flotation. The effects of NTIA on minerals are investigated through microflotation experiments. Flotation experimental results show that NTIA provides good flotation and separation effects on the scheelite in a wide range of pulp pH (6.0–10.0). At pH 7.0, the flotation recovery of scheelite reaches 96.89%, while calcite to only 10%. Moreover, it also reveals an efficient separation effect for artificial mixed minerals of scheelite and calcite under certain conditions. The adsorption behavior of NTIA on scheelite is further studied using wettability test, infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and zeta potential analysis. The results demonstrate that the surface of scheelite is preferentially modified, increasing its hydrophobicity after treatment with NTIA. Meanwhile, under the action of hydrogen bonding and strong electrostatic field in the hydrophilic N–H group of NTIA, the NTIA molecules are absorbed on the scheelite surface.