The flotation performance and adsorption mechanism of α-hydroxyoctyl phosphinic acid (HPA) on pyrochlore were investigated through micro-flotation experiments, zeta-potential tests, contact angle measurements and XPS analysis. The flotation results demonstrated that, in comparison to N-hexadecylpropane-1,3-diamine (NHDA), HPA exhibited a comparable collecting ability for pyrochlore but displayed superior selectivity against feldspar and quartz. Adsorption experiments revealed that the pyrochlore exhibited a higher adsorption capacity for HPA compared to feldspar and quartz. The contact angle experiments indicated that the treatment with HPA significantly increased the contact angle for pyrochlore and calcite, while only minimal changes were observed for feldspar and quartz. Zeta potential and XPS data provided evidence for the chemical adsorption of HPA onto pyrochlore surfaces. Detailed XPS results showed that P-OH groups in HPA formed P(III)-O-M (M = Ca and Nb) bonds with Ca and Nb species on the pyrochlore surface. Additionally, the P-H bond in the HPA molecule could undergo a Redox reaction with highly oxidized Nb, resulting in the formation of a P(V)-Nb(IV) bond. This P(V)-Nb(IV) bond enhances the adsorption of hydrophobic HPA onto the mineral, making it easier to recover pyrochlore through flotation.

中文翻译：

---

α-羟基辛基次膦酸对烧绿石的浮选性能及吸附机理


通过微浮选实验、zeta电位测试、接触角测量和XPS分析，研究了α-羟基辛基次膦酸（HPA）在烧绿石上的浮选性能和吸附机理。浮选结果表明，与 N-十六烷基丙烷-1,3-二胺 (NHDA) 相比，HPA 对烧绿石具有相当的捕收能力，但对长石和石英表现出优异的选择性。吸附实验表明，与长石和石英相比，烧绿石对 HPA 表现出更高的吸附能力。接触角实验表明，HPA 处理显着增加了烧绿石和方解石的接触角，而对于长石和石英仅观察到最小的变化。 Zeta 电位和 XPS 数据为 HPA 化学吸附到烧绿石表面提供了证据。详细的 XPS 结果表明，HPA 中的 P-OH 基团与烧绿石表面上的 Ca 和 Nb 物质形成 P(III)-O-M（M = Ca 和 Nb）键。此外，HPA分子中的P-H键可以与高度氧化的Nb发生氧化还原反应，从而形成P(V)-Nb(IV)键。这种 P(V)-Nb(IV) 键增强了疏水性 HPA 在矿物上的吸附，从而更容易通过浮选回收烧绿石。