Malachite is a common copper oxide mineral. The sulfide-xanthate flotation method is the conventional approach for recovering malachite. However, the hydrophobic sulfide layer formed on the malachite surface after sulfidization tends to degrade, the floatation rate of malachite was significantly reduced. To enhance the stability of the sulfide layer on the malachite surface, ammonium salts are added to reinforce the sulfide layer and improve the flotation rate of malachite. This study investigates the effects of sulfidization time and ammonium aluminum sulfate as a reinforcing agent on the flotation behavior and surface characteristics of malachite. Micro-flotation tests indicate that the flotation rate of malachite sulfided for 20 mins decreased by 41.11 % compared to that sulfided for 4 mins. After the addition of ammonium aluminum sulfate for reinforcement, the flotation rate of malachite increased by 42.22 %. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses reveal that the sulfide layer on the malachite surface sulfided for 4 mins is denser than that sulfided for 20 mins. Following the reinforcement with ammonium aluminum sulfate, a significant growth of the copper sulfide particles in the sulfide layer was observed, along with an increase in the thickness of the sulfide layer. X-ray Photoelectron Spectroscopy (XPS) results indicate that the content of the S_n2⁻ component, which is favorable for flotation, on the surface of malachite sulfided for 20 mins decreased by 7.16 % compared to that sulfided for 4 mins. After the addition of ammonium aluminum sulfate for reinforcement, the S_n2⁻ component content increased by 8.19 %. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) further confirmed that the sulfide effect at 4 mins is superior to that at 20 mins, and ammonium aluminum sulfate can improve the sulfide effect under 20 mins of sulfidization conditions. Contact angle and UV spectroscopy analyses indicate that prolonged mechanical stirring under the 20 mins sulfide condition led to the detachment of the sulfide layer on the malachite surface, reducing its hydrophobicity. However, after the reinforcement with ammonium aluminum sulfate, the mechanical strength of the sulfide layer was enhanced, significantly improving the hydrophobicity of the malachite surface.

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孔雀石表面硫化物层稳定性及铵盐诱导硫化增强机理的研究


孔雀石是一种常见的氧化铜矿物。硫化物-黄原酸浮选法是回收孔雀石的常规方法。然而，硫化后孔雀石表面形成的疏水硫化物层趋于降解，孔雀石的浮选速率显著降低。为了增强孔雀石表面硫化物层的稳定性，添加了铵盐以增强硫化物层并提高孔雀石的浮选速率。本研究探讨了硫化时间和硫酸铝铵作为增强剂对孔雀石浮选行为和表面特性的影响。微浮选试验表明，与硫化 4 min 相比，硫化 20 min 的孔雀石浮选速率降低了 41.11 %。加入硫酸铝铵加固后，孔雀石的浮选率提高了 42.22 %。扫描电子显微镜 （SEM） 和能量色散光谱 （EDS） 分析表明，孔雀石表面硫化 4 分钟的硫化层比硫化 20 分钟的硫化层更致密。在用硫酸铝铵加固后，观察到硫化物层中硫化铜颗粒的显着增长，同时硫化物层的厚度增加。X 射线光电子能谱 （XPS） 结果表明，硫化 20 min 的孔雀石表面有利于浮选的 S_n2⁻ 组分的含量比硫化 4 min 的孔雀石表面降低了 7.16 %。加入硫酸铝铵加固后，S_n2⁻ 组分含量增加了 8.19 %。 飞行时间二次离子质谱 （ToF-SIMS） 进一步证实，4 min 时的硫化效果优于 20 min 时的硫化效果，硫酸铝铵在 20 min 硫化条件下可改善硫化效果。接触角和紫外光谱分析表明，在 20 分钟硫化物条件下长时间的机械搅拌导致孔雀石表面的硫化物层脱落，从而降低其疏水性。然而，用硫酸铝铵加固后，硫化物层的机械强度增强，显著提高了孔雀石表面的疏水性。