Abstract: This paper studied the feasibility of separating bastnaesite from fluorite using PBTCA (2-phosphono-1,2,4-butanetricarboxylic acid) as a depressant in the presence of sodium oleate collectors. The single mineral flotation results indicate that the sodium oleate collector exhibits good collecting for both bastnaesite and fluorite. At the same time, PBTCA can selectively inhibit fluorite flotation without affecting bastnaesite flotation. The artificial mixed mineral flotation tests reveal that the grade and recovery of CeO are 56.58% and over 80% in the concentrate in the PBTCA and sodium oleate reagent scheme, achieving the flotation separation between bastnaesite and fluorite. Zeta potential results demonstrate that the interaction of PBTCA with fluorite surface is stronger than that of PBTCA with bastnaesite, selectively inhibiting the adsorption of the sodium oleate collector on the bastnaesite surface. XPS analysis indicates that PBTCA achieves selective inhibition by chemically interacting with Ca²⁺ on the surface of fluorite through its carboxyl and phosphonate groups in its molecular structure, thus realizing the selective inhibition of fluorite in the bastnaesite flotation.