As an essential raw material for the tin industry, cassiterite ore needs to be effectively separated and purified, and the removal of impurities such as fluorite becomes the key to cassiterite flotation. In this study, the flotation separation of cassiterite (SnO₂) and fluorite (CaF₂) was enhanced by using hydroxylcitric acid (HCA) as fluorite inhibitor and 2-carboxyphenyl phosphonic acid (CEPPA) as collector. With a reagent scheme of 120 mg/L CEPPA and 4.5 mg/L HCA at pH 10.0, the flotation recovery of cassiterite and fluorite was 92.80% and 13.57%, respectively. Under the same experimental conditions of artificially mixed mineral flotation, the flotation index of cassiterite concentrate grade 78.19% and recovery 90.29% was obtained. The selective adsorption mechanism of CEPPA and HCA on minerals was investigated by Zeta potential, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results showed that CEPPA anions had chemically adsorbed on cassiterite and fluorite, and the adsorption of HCA on fluorite surface was stronger than that on cassiterite surface. XPS analyses further confirmed that Ca sites exposed on fluorite had a stronger affinity for HCA than cassiterite. Furthermore, the addition of HCA had little effect on the adsorption of CEPPA on cassiterite, while the strong chemisorption of HCA on fluorite surface prevented the adsorption of CEPPA on fluorite. These results provide a theoretical basis and promising new strategy for the flotation separation of cassiterite and fluorite.

作为锡工业必不可少的原料，锡石矿石需要进行有效的分离提纯，而萤石等杂质的去除成为锡石浮选的关键。本研究采用浮选分离锡石（SnO ₂）和萤石（CaF ₂) 通过使用羟基柠檬酸 (HCA) 作为萤石抑制剂和 2-羧基苯基膦酸 (CEPPA) 作为捕收剂来增强。采用 120 mg/L CEPPA 和 4.5 mg/L HCA 在 pH 10.0 的试剂方案，锡石和萤石的浮选回收率分别为 92.80% 和 13.57%。在相同的人工混合矿物浮选实验条件下，得到锡石精矿品位78.19%、回收率90.29%的浮选指数。采用Zeta电位、傅里叶变换红外光谱(FT-IR)和X射线光电子能谱(XPS)研究了CEPPA和HCA对矿物的选择性吸附机理。结果表明，CEPPA阴离子对锡石和萤石都有化学吸附，HCA在萤石表面的吸附强于锡石表面。XPS 分析进一步证实，暴露在萤石上的 Ca 位点对 HCA 的亲和力比锡石强。此外，HCA的添加对CEPPA在锡石上的吸附影响不大，而HCA在萤石表面的强化学吸附阻碍了CEPPA在萤石上的吸附。这些结果为锡石和萤石的浮选分离提供了理论依据和有前景的新策略。