National Engineering Research Centre of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, China.
Sinopec Ningbo Engineering Co., Ltd., Ningbo 315103, China.
Molecules. 2022 Dec 18;27(24):9026. doi: 10.3390/molecules27249026.
The efficient dispersion of particles is a prerequisite for the efficient flotation of fine smithsonite. However, unavoidable ions (Ca2+) in the pulp have become a challenge for the efficient separation of fine smithsonite, due to the high content of pulp and small radius of hydrated ions. Therefore, the dispersion behavior and mechanism of Ca2+ action on smithsonite are important for improving the efficiency of smithsonite flotation. In this study, the effects of Ca2+ on the dispersion behavior of fine smithsonite were studied using a turbidity test. The results showed that the dispersion behavior of smithsonite was good in the absence of Ca2+ at a range of pH = 4−12. However, the measured turbidity values of smithsonite decreased with the addition of calcium ions. In particular, the dispersion behavior of smithsonite became worse at pH > 10. Zeta potential test results showed that the smithsonite’s surface potential shifted positively, and the absolute value of potential decreased in the presence of Ca2+. The results of X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analysis showed that calcium ions were adsorbed on the smithsonite surface, which may have caused ion exchange or the generation of calcium hydroxide precipitation leading to particle coalescence behavior. The calculations of solution chemistry and DLVO theory indicated that calcium ions adsorbed on the surface of smithsonite to form Ca(OH)+ or precipitation, which reduced the potential energy of interparticle interactions and led to the disruption of dispersion behavior of smithsonite.
粒子的有效分散是细菱锌矿浮选效率的前提。然而，由于矿浆中不可避免的离子（Ca2+）含量高且水合离子半径小，细菱锌矿的高效分离成为一个挑战。因此，Ca2+对菱锌矿作用的分散行为和机理对于提高菱锌矿浮选效率具有重要意义。在本研究中，通过浊度试验研究了 Ca2+对细菱锌矿分散行为的影响。结果表明，在 pH = 4-12 的范围内，不存在 Ca2+时，菱锌矿的分散行为良好。然而，随着钙离子的加入，菱锌矿的实测浊度值降低。特别是，在 pH > 10 时，菱锌矿的分散行为变得更差。动电位测试结果表明，菱锌矿表面电位向正方向移动，表面电位绝对值降低。X 射线光电子能谱（XPS）和扫描电子显微镜（SEM）分析结果表明，钙离子吸附在菱锌矿表面，可能导致离子交换或生成氢氧化钙沉淀，导致颗粒团聚行为。溶液化学和 DLVO 理论的计算表明，钙离子吸附在菱锌矿表面形成 Ca(OH)+或沉淀，从而降低了颗粒间相互作用的位能，导致菱锌矿分散行为的破坏。
