Iron is an impurity widely occurred in sphalerite, and its effect on sphalerite flotation is complex. In this work, the effects of iron content and spin state on electronic properties and floatability of iron-bearing sphalerite are comprehensively studied using density functional theory Hubbard U (DFT+U) calculations combined with coordination chemistry flotation. The band gap of ideal sphalerite is 3.723 eV, and thus electron transition is difficult to occur, resulting in poor floatability. The results suggest the band gap of sphalerite decreases with increasing iron content. For low iron content, the decreased band gap facilitates electron transition; at this case, Fe²⁺ in a high-spin state possesses one π electron pair, which can form a weak π-backbonding with xanthate, causing increasing floatability. However, for medium and high iron-bearing sphalerite, with the further decrease of band gap, Fe²⁺ is oxidized to Fe³⁺ due to electrochemical interaction, and hence π-backbonding is eliminated, leading to lower floatability of iron-bearing sphalerite, which is consistent with the flotation experimental results. This work could give a deeper understanding of how sphalerite flotation behaviors are affected by iron content.

铁是闪锌矿中广泛存在的杂质，其对闪锌矿浮选的影响复杂。本工作利用密度泛函理论Hubbard U（DFT+U）计算结合配位化学浮选，综合研究了铁含量和自旋态对含铁闪锌矿电子性质和可浮性的影响。理想闪锌矿的带隙为3.723 eV，电子跃迁难以发生，导致可浮性较差。结果表明，闪锌矿的带隙随着铁含量的增加而减小。对于低铁含量，减小的带隙有利于电子跃迁；此时，高自旋态的Fe ^{2+拥有一对π电子对，可以与黄药形成弱π背键，从而提高可浮性。}然而，对于中、高含铁闪锌矿，随着带隙进一步减小，Fe ²⁺由于电化学作用被氧化为Fe ³⁺ ，从而消除π背键合，导致含铁闪锌矿可浮性降低，这与浮选实验结果一致。这项工作可以更深入地了解铁含量如何影响闪锌矿浮选行为。