Wrighton-Araneda Kerry, Ruby-Figueroa René, Estay Humberto, Cortés-Arriagada Diego
Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Ignacio Valdivieso 2409, P.O. Box 8940577, San Joaquín, Santiago, Chile.
Advanced Mining Technology Center (AMTC), University of Chile, Av. Tupper 2007 (AMTC Building), Santiago, Chile.
J Mol Model. 2019 Aug 31;25(9):291. doi: 10.1007/s00894-019-4161-x.
The interaction of HO onto small CuS, CuS, and ZnS clusters was theoretically studied by Density Functional Theory computations to get insights into the aggregation characteristics of metal sulfides at aqueous solutions. The results show the charge-controlled interactions with polarized solvent molecules are favored on the ZnS clusters compared with CuS and CuS clusters. Moreover, the chemical adsorption of HO molecules is energetically favored onto ZnS clusters with higher interaction energies of up to 35.4 kcal/mol compared with CuS and CuS clusters (up to 31.3 kcal/mol), where the stability of HO adsorption decreases as the size of the clusters increases. However, thermochemical analysis shows that the adsorption of HO on copper sulfides is not a spontaneous process at room temperature. Additionally, the electrostatic energy of HO onto the CuS and CuS clusters is lower than that associated with the HO-HO interactions, suggesting that copper precipitates prefer to bind between them at early stages of the precipitation process due to an unfavorable solvent-solute interaction. Dispersion forces play a relative key role in the interaction of water on copper sulfides, while for zinc sulfide clusters, the adsorption energy is slightly influenced by dispersion contributions. Accordingly, the aggregation of zinc sulfides in a water environment is expected to be lower compared with copper sulfides, and where the aggregation characteristics are not determined by the binding energy of the sulfides, but of the ability to interact with the solvent molecules. These statements were confirmed by experimental optical microscopy analysis and settling tests during precipitation processes in water. Therefore, this work allows proposing a simple strategy to study the aggregation characteristics of metal sulfides, which turns useful for use in hydrometallurgical applications.
通过密度泛函理论计算从理论上研究了羟基自由基（HO）与小尺寸硫化铜（CuS）、硫化亚铜（Cu₂S）和硫化锌（ZnS）团簇之间的相互作用，以深入了解金属硫化物在水溶液中的聚集特性。结果表明，与硫化铜和硫化亚铜团簇相比，硫化锌团簇更倾向于与极化溶剂分子发生电荷控制的相互作用。此外，羟基自由基分子在硫化锌团簇上的化学吸附在能量上更有利，与硫化铜和硫化亚铜团簇相比，其相互作用能高达35.4千卡/摩尔（硫化铜和硫化亚铜团簇最高为31.3千卡/摩尔），其中羟基自由基吸附的稳定性随着团簇尺寸的增加而降低。然而，热化学分析表明，在室温下，羟基自由基在硫化铜上的吸附不是一个自发过程。此外，羟基自由基在硫化铜和硫化亚铜团簇上的静电能低于与羟基自由基-羟基自由基相互作用相关的静电能，这表明由于溶剂-溶质相互作用不利，在沉淀过程的早期阶段，铜沉淀物更倾向于在它们之间结合。色散力在水与硫化铜的相互作用中起着相对关键的作用，而对于硫化锌团簇，吸附能受色散作用的影响较小。因此，预计在水环境中硫化锌的聚集程度低于硫化铜，并且聚集特性不是由硫化物的结合能决定的，而是由与溶剂分子相互作用的能力决定的。这些结论在水沉淀过程中的实验光学显微镜分析和沉降试验中得到了证实。因此，这项工作提出了一种研究金属硫化物聚集特性的简单策略，这在湿法冶金应用中很有用。
