Abstract Sulfidization followed by xanthate flotation is an effective technique to recover copper oxide minerals. However, the sulfidization mechanism of malachite has not been determined. In this work, the sulfidization mechanism was investigated by microflotation, field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), electron probe X-ray microanalysis (EPMA), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The flotation results showed that sulfide ions at an appropriate concentration could activate malachite flotation while excess sulfide ions could depress this. The depression of malachite flotation by excess sulfide ions was attributed to the residual sulfide species in the liquid. FESEM–EDS showed that sulfidization product grown on the malachite surface was heterogeneously distributed, which was consistent with the EPMA results. The XRD results for the sulfidized malachite samples showed that the amount of sulfidization product was insufficient for detection under flotation-related conditions. By the selective solvent action of sulfuric acid, the sulfidization product was extracted from the sulfidized malachite. The XRD results for the extracts indicated that the sulfidization product comprised djurleite (Cu31S16) and anilite (Cu7S4), which both were compounds of the chalcocite group (Cu2−xS), suggesting transformation of solid Cu2(OH)2CO3 to Cu2−xS on the malachite surfaces during sulfidization. Moreover, the XPS results were consistent with the XRD results. These results demonstrated that sulfidization of malachite is a phase-transition process driven by the solubility difference between Cu2(OH)2CO3 and Cu2−xS. In this case, Cu2−xS phases formation on malachite involves heterogeneous nucleation and growth, and sulfide ions act as a reductant and sulfidizing agent in malachite sulfidization. The copper sulfide grown on malachite radically changed the surface properties of malachite particles, rendering malachite amenable to xanthate flotation. Based on these findings, we present a new formula for malachite sulfidization and a schematic diagram of the sulfidized malachite particle.

中文翻译：

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孔雀石浮选中的硫化机理：一种在孔雀石上生成 CuxSy 相的非均相固液反应

摘要 硫化后黄药浮选是回收氧化铜矿物的有效技术。然而，孔雀石的硫化机理尚未确定。在这项工作中，通过微浮选、场发射扫描电子显微镜（FESEM）、能量色散谱（EDS）、电子探针 X 射线显微分析（EPMA）、X 射线衍射（XRD）和 X 射线光电子学研究了硫化机理。光谱（XPS）。浮选结果表明，适当浓度的硫化物离子可以激活孔雀石浮选，而过量的硫化物离子则可以抑制浮选。过量硫化物离子对孔雀石浮选的抑制归因于液体中残留的硫化物物种。FESEM-EDS 显示孔雀石表面生长的硫化产物是不均匀分布的，这与 EPMA 结果一致。硫化孔雀石样品的 XRD 结果表明硫化产物的量不足以在浮选相关条件下进行检测。通过硫酸的选择性溶剂作用，从硫化孔雀石中提取硫化产物。提取物的 XRD 结果表明硫化产物包含辉沸石 (Cu31S16) 和苯沸石 (Cu7S4)，它们都是辉铜矿组 (Cu2-xS) 的化合物，表明固体 Cu2(OH)2CO3 在硫化过程中孔雀石表面。此外，XPS 结果与 XRD 结果一致。这些结果表明孔雀石的硫化是由 Cu2(OH)2CO3 和 Cu2-xS 之间的溶解度差异驱动的相变过程。在这种情况下，孔雀石上的 Cu2-xS 相形成涉及异质成核和生长，硫化物离子在孔雀石硫化过程中充当还原剂和硫化剂。在孔雀石上生长的硫化铜从根本上改变了孔雀石颗粒的表面性质，使孔雀石适合黄药浮选。基于这些发现，我们提出了孔雀石硫化的新公式和硫化孔雀石颗粒的示意图。