Zinc sulfides, as crucial resources for obtaining metal zinc, frequently coexisting with pyrite and being separated in alkaline pulp. However, the alkaline pulp poses a significant environmental burden. In response, the alkali-free zinc beneficiation reagent system is developed. Herein, findings from solution chemistry analysis favors the classical surface deposition mode of activator Cu(II) on sphalerite. However, adsorption capacity studies reveal that this mode is exclusive to alkaline pulp with pH exceeding 9.5. In neutral pulp, Cu(II) prefers the ion-exchange adsorption mode. DFT calculations further underscore that the Cu(II) ion-exchanged on sphalerite serves as a target for the interfacial adsorption of collector O-(2-methylpropyl) N-prop-2-enylcarbamothioate (MPECT). Notably, the energy selectivity index (ESI) for the adsorption of MPECT and H2O molecule at the Cu target is 15.63 %, significantly surpassing the 3.82 % observed in direct adsorption at the Zn site. In addition, XPS confirmed that after the modification of the sphalerite by Cu(II), some of the surface-attached Cu2+ cations were reduced to Cu+ cations by S2− anions. This valence state composition, which is similar to that of covellite, facilitates the interfacial adsorption of MPECT. This work sheds a solid theoretical foundation and practical reference for the alkali-free beneficiation of zinc sulfide minerals.

中文翻译：

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新试剂 O-（2-甲基丙基） N-丙-2-烯基氨基甲硫代酸酯在硫化锌工业净化中的应用：机理研究

硫化锌作为获得金属锌的重要资源，经常与黄铁矿共存并在碱性纸浆中分离。然而，碱性纸浆对环境造成了重大负担。作为回应，开发了无碱选矿试剂系统。在此，溶液化学分析的结果支持活化剂 Cu（II） 在闪锌矿上的经典表面沉积模式。然而，吸附能力研究表明，这种模式是 pH 值超过 9.5 的碱性纸浆所独有的。在中性纸浆中，Cu（II） 更喜欢离子交换吸附模式。DFT 计算进一步强调，闪锌矿上交换的 Cu（II） 离子是捕收剂 O-（2-甲基丙基） N-prop-2-烯基氨基甲硫代酸酯 （MPECT） 界面吸附的目标。值得注意的是，MPECT 和 H2O 分子在 Cu 靶材上吸附的能量选择性指数 （ESI） 为 15.63%，显著超过在 Zn 位点直接吸附时观察到的 3.82%。此外，XPS 证实，在闪锌矿被 Cu（II） 改性后，一些表面附着的 Cu2+ 阳离子被 S2− 阴离子还原为 Cu+ 阳离子。这种价态组成类似于 covellite 的组成，促进了 MPECT 的界面吸附。本研究为硫化锌矿物的无碱选矿奠定了坚实的理论基础和实践参考。