Effect of lattice defects on the electronic structures and floatability of pyrites

• Published in: International journal of minerals, metallurgy and materials metallurgy and materials, 2012-12, Vol.19 (12), p.1069-1076
• Main Authors: Xian, Yong-jun, Wen, Shu-ming, Chen, Xiu-ming, Deng, Jiu-shuai, Liu, Jian
• Format: Article
• Language: English
• Subjects: Ceramics; Characterization and Evaluation of Materials; Charge density; Chemistry and Materials Science; Cobalt; Composites; Corrosion and Coatings; Covalence; Crystal defects; Density functional theory; Electron density; Flotation; Glass; Gold; Heat treating; Materials Science; Mathematical analysis; Metallic Materials; Natural Materials; Oxidation; Pyrite; Substitutes; Surfaces and Interfaces; Thin Films; Tribology; 共价连接; 可浮性; 密度泛函理论; 强碱性介质; 晶格缺陷; 电子结构; 计算结果; 黄铁矿
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-012-0672-5

The electronic structures of three types of lattice defects in pyrites （i.e., As-substituted, Co-substituted, and intercrystalline Au py-rites） were calculated using the density functional theory （DFT）. In addition, their band structures, density of states, and difference charge density were studied. The effect of the three types of lattice defects on the pyrite floatability was explored. The calculated results showed that the band-gaps of pyrites with Co-substitution and intercrystalline Au decreased significantly, which favors the oxidation of xanthate to dix-anthogen and the adsorption of dixanthogen during pyrite flotation. The stability of the pyrites increased in the following order： As-substituted 〈 perfect 〈 Co-substituted 〈 intercrystalline Au. Therefore, As-substituted pyrite is easier to be depressed by intensive oxidi-zation compared to perfect pyrite in a strongly alkaline medium. However, Co-substituted and intercrystalline Au pyrites are more difficult to be depressed compared to perfect pyrite. The analysis of the Mulliken bond population and the electron density difference indicates that the covalence characteristic of the S Fe bond is larger compared to the S S bond in perfect pyrite. In addition, the presence of the three types of lattice defects in the pyrite bulk results in an increase in the covalence level of the S Fe bond and a decrease in the covalence level of the S S bond, which affect the natural floatability of the pyrites.