闪锌矿银活化及对黄药吸附影响的第一性原理研究

The First-principle Study of Silver Activation and Xanthate Adsorption on Sphalerite Surface

为深入研究银离子对闪锌矿的活化机理,采用第一性原理对闪锌矿表面Ag^(+)替换活化和吸附活化分别开展了模拟研究,同时研究了银活化对闪锌矿表面黄药吸附的影响。计算结果表明,未活化的闪锌矿表面不与乙基黄药发生相互作用,银活化的闪锌矿表面能够与乙基黄药发生相互作用。在两种银活化模型中,Ag^(+)吸附活化比替换活化在能量上更容易发生。Ag^(+)替换活化的闪锌矿表面,黄药的S与表面Ag相互作用较弱;而在Ag^(+)吸附活化的闪锌矿表面,黄药的S与表面Ag相互作用较强。态密度分析表明,在Ag^(+)吸附活化的闪锌矿表面,黄药S原子的3p态和Ag原子的4 d态具有较多成键轨道电子云重叠区域,说明表面吸附的Ag^(+)与黄药的S原子发生了较强的相互作用。Mulliken电荷分析表明,与替换活化相比,黄药和Ag^(+)吸附活化的闪锌矿表面有更多的电荷转移,进一步说明Ag^(+)吸附活化更有可能发生。

In order to further study the activation mechanism of silver ions on sphalerite,the Ag^(+) substitution and adsorption mechanism on sphalerite were studied by density functional theory.Meanwhile,the activation effect of silver to the adsorption of xanthate on sphalerite was studied.The results showed that ethyl xanthate did not interact with the un-activated sphalerite surface but could have strong interaction with the Ag^(+)-activated sphalerite surface.Compare with the two activation models,Ag^(+) adsorption activation was more likely to occur in terms of energy than Ag^(+) substitution activation.On the Ag^(+) substitution-activated sphalerite surface,the S atom of xanthate interacted weakly with surface Ag atom,while on the Ag^(+) adsorption-activated sphalerite surface,the S atom of xanthate interacted strongly with surface Ag atom.Density of states analysis showed that on Ag^(+) adsorption-activated sphalerite surface,the 3p state of S atom and the 4d state of Ag atom had many overlapping regions of bonding orbital electron clouds.This indicated that adsorption-activated Ag^(+) had a strong interaction with S atom of xanthate.Mulliken charge analysis showed that there was more charge transfer between the Ag^(+) adsorption-activated sphalerite surface and xanthate,which further indicated that Ag^(+) adsorption-activation was more likely to occur.