十二胺和油酸组合捕收剂在锂云母表面吸附的分子动力学模拟

发布时间：2018-06-07 18:46

本文选题：量子化学 + 分子动力学　；参考：《江西理工大学》2017年硕士论文

【摘要】：随着浮选理论的发展,对浮选体系的研究不只停留在不同因素影响下的回收率的研究上,研究人员借助于新兴的研究手段——分子模拟,通过对浮选体系的建模,从微观领域更直观的观察浮选反应中药剂及水在矿物表面的作用方式与分子动力学过程,加深了对浮选机理的理解。本文采用量子化学方法,对锂云母及(001)表面的构型参数和性质进行了分析,并探究了锂云母构型参数与浮选性能之间的相互联系。利用分子动力学相关软件探究了捕收剂分子与锂云母作用面的吸附机理,并利用锂云母实际矿物进行浮选验证。锂云母电子结构研究表明,锂云母晶体结构中费米能级附近的态密度是由O2p、Si3p主要贡献,所以O、Si为锂云母表面的活性位点。锂云母浮选试验时矿物表面解离,露出大量的K+和[SiO4]-,K+在水溶液中极易溶解,锂云母作用面可以与羟基发生相互结合,使得在很宽的pH值范围内锂云母带负电并且零电点很低,造成锂云母较易用十二胺进行浮选回收,而不易用油酸钠。锂云母(001)面与捕收剂分子的作用构型表明,水条件下,水化作用在表面K+离子与锂云母表面的相互作用中并不占优势,表面K+离子仍然吸附在锂云母表面。水分子在锂云母(001)面形成水分子层,吸附能为-11.35 kcal/mol小于药剂分子在锂云母表面的相互作用能,因此药剂分子与锂云母(001)面发生相互作用的络合构型中二者中间隔着水分子层。三者对锂云母的捕收性能为组合捕收剂(十二胺和油酸)十二胺油酸,与真空环境一致。-NH2与锂云母(001)面的作用强度大于-OH与锂云母(001)面的吸附强度。试验中,捕收剂分子借助-COOH或-NH2吸附在锂云母(001)面的水分子层,并借助于烃链的疏水性实现锂云母与水的浮选分离。用组合捕收剂(十二胺和油酸)浮选锂云母时,配比1:1的组合捕收剂在锂云母(001)面的吸附效果最佳,组合捕收剂在中性和中碱的环境下,有利于锂云母的浮选。纯矿物浮选试验,验证了组合捕收剂配比为1:1时,在中性环境下对锂云母矿的的捕收能力大于单一捕收剂的捕收能力。
[Abstract]:With the development of flotation theory, the study of flotation system is not only focused on the study of the recovery rate under the influence of different factors, but also through the modeling of flotation system by means of molecular simulation, a new research tool. The mechanism of flotation is better understood by observing the action mode of reagent and water on mineral surface and the process of molecular dynamics more intuitively in the micro field. In this paper, the configuration parameters and properties of spodumite and spodumite surface are analyzed by means of quantum chemistry, and the relationship between the configuration parameters and flotation properties of spodumite is discussed. The adsorption mechanism between collector molecule and spodumite interaction surface was investigated by molecular dynamics software, and the flotation verification of spodumite mineral was carried out. The electronic structure of spodumite shows that the density of states near Fermi level in spodumite crystal structure is mainly contributed by O _ 2pN _ Si _ 3p, therefore, Oo _ (Si) is the active site on the surface of spodumite. During the flotation test of spodumite, the mineral surface is dissociated and a large amount of K and [SiO4] -K are easily dissolved in aqueous solution. The spodumite interaction surface can be combined with hydroxyl group, which makes spodumite with negative charge and low zero current point in a wide pH range. Spodumite is easy to be recovered by floatation with dodecylamine, but sodium oleate is not easy to be recovered. The configuration of the interaction between spodolite surface and collector molecule shows that the hydration is not dominant in the interaction between K ion and spodolite surface, and the surface K ion is still adsorbed on the surface of spodolite. Water molecules form a layer of water molecules on the spodumite surface. The adsorption energy of -11.35 kcal/mol is less than that of the interaction energy of the reagent molecules on the surface of spodumite. Therefore, in the complex configuration of the interaction between the reagent molecules and the spodumite surface, there is a water molecular layer between the two molecules. The collection performance of the three groups for lepidolite is that the combined collector (dodecylamine and oleic acid) dodecylamine oleic acid, and the interaction strength of .-NH _ 2 with spodumite 001) surface is greater than that of -OH and spodumite _ 001 surface in vacuum environment. In the experiment, the collector molecule was adsorbed on the surface of spodumite 001 by -COOH or -NH _ 2, and the flotation separation of spodumite and water was realized by hydrophobicity of hydrocarbon chain. When the combined collector (dodecylamine and oleic acid) is used for the flotation of spodumite, the combined collector of 1:1 has the best adsorption effect on the surface of spodumite. The combined collector is advantageous to the flotation of spodumite in neutral and moderate alkali environment. The flotation tests of pure minerals show that the collection capacity of spodumite ore in neutral environment is greater than that of single collector when the ratio of combined collector is 1:1.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD923.13;TD97

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