Abstract Although numerous studies on the flotation depression of sphalerite by calcium have been reported, certain issues warrant further investigation. Previous research works did not examine the role that the iron content of iron-bearing sphalerite plays in calcium depression and did not obtain direct and convincing microscopic evidence of calcium adsorption to support the depression of calcium-containing ions on iron-bearing sphalerite’s flotation. In this paper, the effects of iron content and the presence of calcium on iron-bearing sphalerite’s flotation depression under high alkalinity environment are studied using flotation tests, adsorption amount measurements, surface extraction, zeta potential measurements, time-of-flight secondary-ion mass spectrometry (TOF-SIMS) and density functional theory (DFT) calculations. The results show that increasing iron content or the presence of calcium will lead to an increase in the degree of flotation depression and will reduce the adsorption of copper and xanthate. Increasing iron content will cause the surface of iron-bearing sphalerite to adsorb more metal hydroxides (especially iron hydroxide) and calcium. The TOF-SIMS results confirmed the trend of calcium adsorption at the atomic level. DFT calculations show that the adsorption energy of CaOH+ on the surface of iron-substituted sphalerite is lower than that on the surface of ideal sphalerite. The following conclusions can be obtained through analysis of the aforementioned: Increase in the adsorption of hydroxides (especially iron hydroxide) and calcium significantly hinder the adsorption of copper and xanthate, and increase the hydrophilicity of high-iron sphalerite surface, which ultimately leads to an increase in the degree of flotation depression of high-iron sphalerite with increasing iron content.

中文翻译：

---

高碱度环境下钙对高铁闪锌矿浮选的抑制机制研究

摘要 尽管已经报道了大量关于钙对闪锌矿浮选的抑制作用的研究，但某些问题值得进一步研究。以前的研究工作没有考察含铁闪锌矿的铁含量在钙抑制中的作用，也没有获得钙吸附的直接和令人信服的微观证据来支持含钙离子对含铁闪锌矿的浮选的抑制。本文采用浮选试验、吸附量测定、表面萃取、zeta电位测定、飞行时间二次离子等方法研究了铁含量和钙的存在对高碱度环境下含铁闪锌矿浮选抑制的影响。质谱 (TOF-SIMS) 和密度泛函理论 (DFT) 计算。结果表明，增加铁含量或钙的存在会导致浮选抑制程度增加，并会降低铜和黄药的吸附。增加铁含量会使含铁闪锌矿表面吸附更多的金属氢氧化物（尤其是氢氧化铁）和钙。TOF-SIMS 结果证实了原子水平上钙吸附的趋势。DFT计算表明，CaOH+在铁取代闪锌矿表面的吸附能低于在理想闪锌矿表面的吸附能。由上述分析可以得出以下结论： 氢氧化物（特别是氢氧化铁）和钙吸附的增加显着阻碍了铜和黄药的吸附，