Correlation of Surface Adsorption and Oxidation with a Floatability Difference of Galena and Pyrite in High-Alkaline Lime Systems
Correlation of Surface Adsorption and Oxidation with a Floatability Difference of Galena and Pyrite in High-Alkaline Lime Systems
复制标题
高碱石灰体系中方铅矿和黄铁矿表面吸附和氧化与可浮性差异的相关性
DOI：
10.1021/acs.langmuir.7b04189
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发表时间：
2018-02-27
期刊：
影响因子：
3.9
通讯作者：
Tan, Qaoyi
中科院分区：
文献类型：
--
作者：
Niu, Xiaopeng;Ruan, Renman;Tan, Qaoyi
对于黄铁矿含量高的铅锌矿，遇到的主要问题是方铅矿与黄铁矿的分离效率低。通过高剂量石灰和捕收剂二乙基二硫代氨基甲酸钠（DDTC），抑制黄铁矿和锌矿物，使方铅矿浮选。然而，有显着的冲突的报道方铅矿在高pH值的浮选行为。在这种情况下，表面吸附和氧化的相关性与方铅矿和黄铁矿在高碱性石灰系统的可浮性差异将是一个关键问题，工艺优化。捕获气泡接触角的测量进行了新抛光的矿物表面在原位暴露于不同pH值的石灰溶液作为浸泡时间的函数。此外，还进行了单矿物微浮选试验。这两个测试表明，在自然或温和的纸浆pH值的DDTC的存在下，方铅矿和黄铁矿的表面上的疏水性的程度增加。而在饱和石灰溶液中，在pH值12.5，DDTC只为方铅矿，但不为黄铁矿。通过飞行时间二次离子质谱（TOF-SIMS）的表面化学分析证实了在pH 12.5的方铅矿表面上DDTC的偏好，这有助于优点恢复。通过Tof-SIMS、离子色谱和高效液相色谱的测量进一步得到的重要证据表明，在高碱性石灰体系中，方铅矿的优良可浮性可以排除元素硫（S-8）的微不足道的贡献，并且主要归因于DDTC的强吸附。相反，黄铁矿在高pH下的浮选响应差是由于CaOH+物种的普遍吸附。该研究为深入理解高碱石灰体系方铅矿-黄铁矿分离选择性提高的机理提供了重要的表面化学依据。
When it comes to Pb-Zn ores with high amounts of pyrite, the major problem encountered is the low separation efficiency between galena and pyrite. By virtue of high dosage of lime and collector sodium diethyl dithiocarbamate (DDTC), pyrite and zinc minerals are depressed, allowing the galena to be floated. However, there have been significant conflicting reports on the flotation behavior of galena at high pH. In this context, correlation of the surface adsorption and oxidation with the floatability difference of galena and pyrite in high-alkaline lime systems would be a key issue for process optimization. Captive bubble contact angle measurements were performed on freshly polished mineral surfaces in situ exposed to lime solutions of varying pH as a function of immersion time. Furthermore, single mineral microflotation tests were conducted. Both tests indicated that the degree of hydrophobicity on the surfaces of galena and pyrite increased in the presence of DDTC at natural or mild pulp pH. While in a saturated lime solution, at pH 12.5, DDTC only worked for galena, but not for pyrite. Surface chemistry analysis by time-of flight secondary ion mass spectrometry (Tof-SIMS) confirmed the preference of DDTC on the galena surface at pH 12.5, which contributed to a merit recovery. Further important evidence through measurements of Tof-SIMS, ion chromatography, and highperformance liquid chromatography indicated that in high-alkaline lime systems, the merit floatability of galena could exclude the insignificant contribution of elemental sulfur (S-8) and was dominantly attributed by the strong adsorption of DDTC. In contrast, the poor flotation response of pyrite at high pH was due to the prevailing adsorption of CaOH+ species. This study provides an important surface chemistry evidence for a better understanding of the mechanism on the better selectivity in the galena-pyrite separation adopting high-alkaline lime systems.