ABSTRACT

Sodium sulfide has been widely used as a bismuth depressant in the flotation separation of molybdenum–bismuth sulfide ores. However, the selective depression mechanism of sodium sulfide on bismuthinite remained unclear. In this study, the effect of sodium sulfide on the flotation performance of molybdenite and bismuthinite was systemically investigated through micro-flotation tests, bench-scale flotation tests, Fourier transform infrared (FTIR) measurements, adsorption experiments, and X-ray photoelectron spectroscopy (XPS) analyses. Micro-flotation tests indicated that sodium sulfide had excellent depressing effect on the bismuthinite in alkaline condition. The recovery of bismuthinite dramatically decreased from 86.7% to 16.5% with the concentration of sodium sulfide increased to 1 × 10⁻³ mol/L. By contrast, the depressing effect of sodium sulfide on the flotation of molybdenite was weak. The flotation recovery of molybdenite remained above 60% in the whole pH range tested. Surface analysis using FTIR and XPS analysis revealed that the surface of bismuthinite was covered by hydrophilic sulfide ions after treatment with sodium sulfide, which not only decreased its surface hydrophobicity but also prevented the subsequent adsorption of collector xanthate. While the surface of molybdenite was slightly affected and remained hydrophobic as indicated by high flotation recoveries. Bench-scale flotation tests confirmed that sodium sulfide could be used as an efficient depressant for flotation separation of molybdenite from bismuthinite. The work presented here not only provides a new perspective on the inhibition mechanism of sodium sulfide but also gives a theoretical support for the industrial application of sodium sulfide.

摘要

硫化钠在钼-铋硫化矿的浮选分离中被广泛用作铋抑制剂。然而，硫化钠对铋矿的选择性抑制机制仍不清楚。本研究通过微浮选试验、小型浮选试验、傅里叶变换红外 (FTIR) 测量、吸附实验和 X 射线光电子能谱系统研究了硫化钠对辉钼矿和铋矿浮选性能的影响。 XPS) 分析。微浮选试验表明，硫化钠在碱性条件下对铋矿有很好的抑制作用。随着硫化钠浓度增加到1×10 ^{-3 ，铋矿的回收率从86.7%急剧下降到16.5%} 摩尔/升。相比之下，硫化钠对辉钼矿浮选的抑制作用较弱。在整个测试的 pH 范围内，辉钼矿的浮选回收率保持在 60% 以上。FTIR和XPS表面分析表明，硫化钠处理后的铋矿表面被亲水性硫离子覆盖，不仅降低了其表面疏水性，而且阻止了捕收剂黄药的后续吸附。而辉钼矿的表面受到轻微影响并保持疏水性，如高浮选回收率所示。台架浮选试验证实，硫化钠可用作从辉钼矿中浮选分离辉钼矿的有效抑制剂。