The oxidation of molybdenite in water-oxygen system adversely affects the flotation recovery. However, previous studies primarily focused on the oxidation of MoS2 edge surfaces, neglecting the oxidation of basal facets, which constitute a larger proportion of the overall surface area. In this work, we systematically investigated the oxidation behavior of the molybdenite base surface and explored the influence of base surface oxidation sites on flotation behavior. The results demonstrated that surface oxidation of molybdenite leaded to a negative surface potential, decreased hydrophobicity and reduced dodecane adsorption. Electrostatic potential (ESP) and density functional theory (DFT) calculations revealed that oxidation sites on the molybdenite surface exhibited a strong negative charge, enhancing the adsorption of water molecules while weakening kerosene adsorption. Molecular dynamics (MD) simulations indicated that the oxidized molybdenite surface formed a hydration layer with thickness of ∼ 6 nm, which impedes dodecane adsorption. Moreover, this study proposed an effective strategy to improve molybdenite flotation recovery, that is reducing the concentration of dissolved oxygen in the pulp to inhibit MoS2 oxidation. These findings provide new insights into the oxidation behavior of molybdenite, and contribute to a better understanding of its flotation behavior in pulp.

中文翻译：

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对辉钼矿浮选率显著下降的新见解恢复：被忽视的 MoS2 基面氧化


辉钼矿在水-氧体系中的氧化对浮选回收产生不利影响。然而，以前的研究主要集中在 MoS2 边缘表面的氧化上，而忽略了基面的氧化，基底刻面的氧化占总表面积的较大比例。在这项工作中，我们系统研究了辉钼矿基表面的氧化行为，并探讨了基表面氧化位点对浮选行为的影响。结果表明，辉钼石的表面氧化导致负表面电位，疏水性降低，十二烷吸附减少。静电势 （ESP） 和密度泛函理论 （DFT） 计算表明，辉钼矿表面的氧化位点表现出很强的负电荷，增强了水分子的吸附，同时削弱了煤油的吸附。分子动力学 （MD） 模拟表明，氧化的辉钼矿表面形成了厚度为 ∼ 6 nm 的水化层，阻碍了十二烷的吸附。此外，本研究提出了一种提高辉钼矿浮选回收率的有效策略，即降低纸浆中溶解氧的浓度以抑制 MoS2 氧化。这些发现为辉钼矿的氧化行为提供了新的见解，并有助于更好地了解其在纸浆中的浮选行为。