The interaction of surfactants at minerals-water interfaces in flotation system plays an important role in minerals separation. Although the increasing number of reports have been published on the sodium oleate (NaOL) adsorption at the mineral–water interface, there has been little development in describing and predicting its adsorption behaviors from a quantitative molecular insight. In this study, based the adsorption experiments, the adsorption characteristics of NaOL on the hematite/quartz-water interfaces were quantitatively depicted using the surface complexation model (SCM). There was a monodentate binding form between the function group on NaOL and the hematite and quartz surface sites during SCM fitting. The binding constants (logK) of NaOL are 10.72 (≡Fe-OL) and 8.03 (≡Si-OL), respectively. Notably, there are more positive ≡FeOH site on the hematite surface, and it has strong adsorption capacity with anionic surfactant NaOL. Moreover, the minerals surface potentials, NaOL adsorption capacity and flotation recovery in mixed ore systems were successfully predicted by the model. This study provides a credible evaluation of the adsorption characteristics of NaOL under a broad scope of pH and concentration conditions. Meanwhile, quantitative analysis of surfactants adsorption at minerals-water interfaces is beneficial for the intelligence of mineral processing technology and efficient separation of minerals.

中文翻译：

---

油酸钠在赤铁矿/石英-水界面的吸附机制：定量分子洞察


浮选体系中矿物-水界面表面活性剂的相互作用在矿物分离中起着重要作用。尽管关于矿泉水界面油酸钠（NaOL）吸附的报道越来越多，但从定量分子角度描述和预测其吸附行为方面却几乎没有进展。本研究基于吸附实验，利用表面络合模型（SCM）定量描述了NaOL在赤铁矿/石英-水界面上的吸附特性。在 SCM 拟合过程中，NaOL 上的官能团与赤铁矿和石英表面位点之间存在单齿结合形式。 NaOL 的结合常数 (logK) 分别为 10.72 (e-OL) 和 8.03 (e-OL)。值得注意的是，赤铁矿表面有较多正的 ≡FeOH 位点，对阴离子表面活性剂 NaOL 具有较强的吸附能力。此外，该模型成功预测了混合矿石系统中矿物表面电势、NaOL吸附能力和浮选回收率。这项研究为 NaOL 在广泛的 pH 和浓度条件下的吸附特性提供了可靠的评估。同时，定量分析矿物-水界面表面活性剂的吸附量，有利于选矿技术的智能化和矿物的高效分离。