Abstract: In order to improve the flotation recovery efficiency of niobium minerals at Bayan Obo, a study was conducted on the flotation separation efficiency and adsorption mechanism of a single benzohydroxamic acid (BHA) and a composite collector of benzohydroxamic acid + NPs (hydroxamic acids) on niobium−containing tailings. The results showed that the optimum mass ratio of the composite collector (BHA+NPs) for flotation of niobium minerals was m(NPs)∶m(BHA)=0.35∶0.65. In the closed circuit flotation experiment, a niobium concentrate with a grade of 3.24% Nb₂O₅ and a recovery of 83.03% was obtained. Compared to the single BHA, the concentrate grade was increased by 0.53 percentage points. The composite collector significantly increased the content of niobium minerals in the concentrate, indicating its strong collecting ability for niobium containing minerals. XPS analysis showed that the presence of the auxiliary collector NPs did not change the chemical environment of nitrogen elements on the surface of Niobite, and NPs and BHA were co−adsorbed on the surface of niobite, promoting the adsorption of BHA on the mineral surface.