Flotation behavior and mechanism of a new mixed collector on separation of spodumene from feldspar

New collectors, hexyloxypropylamine (HPA) and N-Dodecyliminodiacetic acid (DIDA) were synthesized in laboratory. The flotation behavior of both collectors on spodumene and feldspar was investigated by micro-flotation tests respectively. A new mixed collector HPA/DIDA was prepared in order to achieve a greater difference of recovery of spodumene and feldspar. Through micro-flotation tests, the flotation behavior of HPA/DIDA on spodumene and feldspar was evaluated. The test results showed that the recovery of spodumene and feldspar was 85.61% and 7.38% respectively under the optimal conditions that the mass ratio of HPA:DIDA was 1:3; HPA/DIDA concentration was at 57.14 mg/L; and the pulp had no pH regulator added. The adsorption mechanism of the collector on spodumene and feldspar surface was established by zeta potential, FT-IR, XPS and surface tension measurements. It was found that HPA was adsorbed on spodumene surface mainly through hydrogen bonds adsorption, then adsorbed on feldspar by electrostatic adsorption. DIDA was adsorbed on spodumene and feldspar surface by chemisorption. While the mixed collector HPA/DIDA was self-assembled to HPA-DIDA complex and got adsorbed on spodumene surface by synergistic effect of chemisorption and hydrogen bonds adsorption, it was adsorbed on feldspar surface only by chemisorption. The difference of Al sites and O sites between spodumene (110) surface and feldspar (010) surface accounted for the selectivity of HPA/DIDA. The coexistence of ―COOH and ―NH2 facilitated the adsorption of HPA/DIDA on spodumene, but it obstructed the adsorption of HPA/DIDA on feldspar, which led to the great recovery disparity of spodumene and feldspar. © 2020 Elsevier B.V.