An SFG spectroscopy study of the interfacial water structure and the adsorption of sodium silicate at the fluorite and silica surfaces
An SFG spectroscopy study of the interfacial water structure and the adsorption of sodium silicate at the fluorite and silica surfaces
复制标题
界面水结构和硅酸钠在萤石和二氧化硅表面吸附的 SFG 光谱研究
DOI：
10.1016/j.mineng.2019.04.028
复制
发表时间：
2019-07
影响因子：
4.8
通讯作者：
Sun Wei
中科院分区：
文献类型：
--
作者：
Han Haisheng;Peng Mengsu;Hu Yuehua;Nguyen Anh V;Sun Wei
硅酸钠（SS）常用作浮选剂或分散剂，以提高泡沫浮选的选择性。SS的抑制能力随浓度和pH值的变化而变化，但其抑制机理尚不清楚。在本文中，和频发生光谱被用来调查在矿物-水界面的水的结构，SS吸附及其在浮选中的作用提供了一个分子的理解。我们的研究表明，大量的硅酸盐物种吸附在萤石-水和硅-水界面在很宽的pH值范围内，独立的表面电位。硅酸盐物种在萤石表面的吸附层在低pH（酸性条件）下可以去除，但在高pH（碱性条件）下难以去除。相反，在二氧化硅表面的硅酸盐物种的吸附是如此之强，吸附的物种不能在整个pH范围内被删除。这一发现与浮选结果一致，即SS在pH = 6-8时可用作萤石的分散剂，但在较高pH下其行为类似于絮凝剂。此外，由于SS与矿物表面的强相互作用，SS在整个pH范围内有效地抑制了二氧化硅的可浮性。这项工作提供了有关SS吸附到矿物表面的分子细节，这是对以前的宏观研究，如FTIR，zeta电位和XPS测量的补充。
Sodium silicate (SS) is often used as a depressant or a dispersant to improve the selectivity of froth flotation. The depressing ability of SS changes with its concentration and the solution pH. However, the depressing mechanism is unclear. In this paper, sum frequency generation spectroscopy was used to investigate the water structure at the mineral-water interface to provide a molecular understanding of SS adsorption and its role in flotation. Our study shows that a significant amount of silicate species adsorbs at the fluorite-water and silica-water interfaces in a wide range of pH, independently of the surface potential. The adsorption layer of silicate species on the fluorite surface can be removed at low pH (acidic condition), but its removal becomes difficult at high pH (basic condition). On the contrary, the adsorption of silicate species at the silica surface is so strong that the adsorbed species cannot be removed at the whole pH range. This finding agrees with flotation results showing that SS can be used as a dispersant for fluorite at pH = 6–8, but it behaves like a depressant at higher pH. Also, SS effectively depresses the silica floatability at the whole range of pH due to its strong interaction with the mineral surface. This work provides the molecular details about the SS adsorption onto the mineral surface which is complementary to the previous macroscopic studies such as FTIR, zeta potential, and XPS measurements.
登录
查看更多内容
影响因子：
4.8
作者：
Qiang Zhou;Shou-ci Lu
通讯作者：
Qiang Zhou;Shou-ci Lu
影响因子：
9.9
作者：
Xiaofang Yang;Payman Roonasi;A. Holmgren
通讯作者：
Xiaofang Yang;Payman Roonasi;A. Holmgren
影响因子：
6.7
作者：
Han, Yonghua;Liu, Wenli;Chen, Jianhua
通讯作者：
Chen, Jianhua
影响因子：
5
作者：
Fenter, Paul;Lee, Sang Soo
通讯作者：
Lee, Sang Soo
影响因子：
4.8
作者：
Wei Chen;Q. Feng;Guofan Zhang;Dezhi Liu;Longfei Li
通讯作者：
Wei Chen;Q. Feng;Guofan Zhang;Dezhi Liu;Longfei Li