Flotation behavior and mechanism of a new amphoteric collector on the flotation separation of spodumene from albite and quartz under low temperature

The flotation behavior of a new amphoteric collector α- di-n-hexylamino-dodecanoic acid (α-DHDA), at low temperature and without activators and depressants, was investigated through the flotation behavior of individual minerals and synthetic mixed ore. In the individual mineral flotation test, when the pulp pH value of 5, a temperature of 10 °C, and a collector concentration of 141 mg/L, the flotation difference between spodumene and albite was 75.27 %, and the flotation disparity between quartz and spodumene was 74.44 %. In the ternary synthetic mixed ore test, when the pulp pH value of 5, a temperature of 10 °C, and a collector concentration of 165 mg/L, spodumene concentrate with Li2O grade of 5.43 % and recovery of 76.98 % was achieved. The flotation outcomes indicated that the collector α-DHDA performed well in selectivity, collecting ability, and temperature adaptability. The selective adsorption mechanism of α-DHDA was revealed through techniques such as contact angle, adsorption capacity, zeta potential, FT-IR, XPS, and ToF-SIMS surface analysis. The findings revealed that α-DHDA could chemically bind to the surfaces of spodumene, albite, and quartz, but due to the differing numbers and activity of active site on the mineral surface, α-DHDA formed stable monolayer chemisorption on the spodumene surface (mainly through the Al site and secondarily through the Si site), which significantly enhancing its hydrophobicity. On the surfaces of albite and quartz, disordered multilayer reverse adsorption easily formed, making it difficult to effectively improve surface hydrophobicity, so as to achieve the effective separation of spodumene from gangue minerals.