【作者】 卢烁十；

【导师】 孙传尧；

【作者基本信息】 东北大学 ， 矿物加工工程， 2008， 博士

【摘要】 天青石(SrSO4)、重晶石(BaSO4)和石膏(CaSO4·2H2O)是重要的硫酸盐矿物,也是重要的盐类矿物,在建筑、化工、医药等领域有着广泛的应用。天青石是碳酸锶的主要来源。碳酸锶的主要用途是生产电视机显像管面板玻璃及永磁材料。重晶石是提取钡盐的主要原料。石膏是重要的非金属材料,广泛应用于工业、农业和医药等领域。天青石、重晶石和石膏的浮选是一项重要的浮选理论与实践课题。这三种硫酸盐矿物常与某些其它盐类矿物伴生,由于表面具有相同活性或性质相近的离子,因此它们之间浮选分离困难。目前,对这三种硫酸盐矿物的浮选研究主要侧重于它们与某些其他盐类矿物之间如方解石、磷灰石、萤石的浮选分离,如重晶石与萤石、重晶石与方解石,天青石与方解石等分离研究。为了深入了解这三种硫酸盐矿物的浮选特性,必须对其浮选进行系统地试验研究。矿物的可浮性与晶体化学特性密切相关。矿物的晶体化学特性是指矿物的化学组成、化学键、晶体结构及其性质之间的关系,决定着矿物在溶液中解离后的表面性质,从而影响矿物的可浮性。因此本文对三种硫酸盐矿物的浮选进行了晶体化学研究。本文从矿物的晶体结构出发,通过大量的浮选试验,对三种硫酸盐矿物在阴离子捕收剂油酸钠、阳离子捕收剂十二胺及螫合捕收剂水杨羟肟酸浮选体系中不加活化剂和抑制剂时的可浮性,以及多价金属阳离子、无机阴离子调整剂、有机高分子化合物和有机螯合化合物对其可浮性的影响进行了系统的研究。同时,借助于晶体化学理论、浮选溶液化学理论以及现代表面测试技术(X射线光电子能谱分析、傅立叶红外光谱分析及ζ电位测定等),对三种硫酸盐矿物进行了晶体化学研究,并尝试运用计算机分子模拟计算对浮选的结果进行了验证。研究表明,在油酸钠和水杨羟肟酸浮选体系中三种矿物的可浮性大小为重晶石>天青石>石膏；在十二胺浮选体系中为：石膏>天青石>重晶石。XPS和红外光谱测试发现,油酸钠与三种硫酸盐矿物的作用为化学吸附,十二胺在矿物表面发生物理吸附,水杨羟肟酸则可能与矿物发生了螯合反应。对三种硫酸盐矿物晶体结构中的化学键进行了理论计算,发现化学键的键长、键能、静电力、离子键百分比和极性及键强决定了Mn+—O2-的断裂程度,而Mn+—O2-的断裂程度与三种硫酸盐矿物的可浮性密切相关。对于天青石和重晶石而言,Sr—O键、Ba—O键大量断裂,Sr2+、Ba2+在矿物表面大量暴露,在浮选溶液中易与阴离子捕收剂油酸钠产生化学吸附,并能与水杨羟肟酸发生螯合反应,因此两种矿物在油酸钠和水杨羟肟酸浮选体系中的可浮性较好。石膏结构中的Ca—O键不易断裂,Ca2+暴露很少,因此石膏表面电负性大,在阳离子捕收剂十二胺浮选体系中有较好的可浮性,好于在阴离子捕收剂油酸钠和螯合捕收剂水杨羟肟酸浮选体系中的可浮性。计算机分子模拟计算的结果表明,矿物与药剂作用前后的能量变化越大,矿物的可浮性越好。计算结果与浮选试验的结果是相符合的。更多还原

【Abstract】 Celestite(SrSO4), barite(BaSO4) and gypsum(CaSO4·2H2O) are three kind of important sulfate minerals, which are also important salt minerals used widely in architecture, chemical industry and medical fields. Barite is a main raw material for extracting barium salt. Celestite is the main source of strontium carbonate, which is often used for producing kinescope panel glasses of TV sets and permanent-magnet materials. Gypsum is a kind of more important nonmetal material, used widely in the field of industry, agriculture and medicine.The flotation of Celestite, barite and gypsum is a significant topic of theory and practice. The three sulfate minerals usually accompany with these salt minerals, having ions with equal activities or similar properties on the surface, which makes the flotation separation difficult. At present, the research on the flotation of the three sulfate minerals mainly laid special emphasis on studying flotation separation between the three sulfate minerals and other salt minerals including calcite, apatite, and fluorite and so on.The floatability of minerals is closed related with their crystal chemistry characteristics. The crystal chemistry characteristics includes chemical composition, chemical bonds, crystal structure and the relation among them, which decide the surface properties of minerals after dissociating in the solution, and then influence the floatability. Consequently, this paper carried out the crystal chemical research on the flotation of the three sulfate minerals.This paper started from the crystal structure, and carried out the systematic study through vast scale flotation experiments on the floatability of the three sulfate minerals without activator and depressant in anion, cation and chelating collectors flotation system, and influence of polyvalent metal cation, inorganic anion modifiers, organic high molecular depressants and organic chelating agents on floatability of them. At the same time, the studies on crystal structures of three typical sulfate minerals with the aid of theory of crystal chemistry, theory of solution chemistry of flotation and modern advanced surface test technique (X-ray photoelectron spectrometric,ζ-potential measure) were carried out for research of crystal chemistry on three sulfate minerals in this paper, and computer simulation calculation was also attempted to carry out for verifying the results of flotation.The research shows that the floatability sequence of three sulfate minerals is barite>celestite>gypsum in the collector systems of sodium oleate and salicylhydroxamic acid; in lauryl amine system is:gypsum>celestite>barite. XPS and infrared spectrum analysis are used to find that it is chemical reaction between sodium oleate and three minerals, physical adsorption on the surface of minerals for lauryl amine, and it is chelating reaction between salicylhydroxamic acid and three minerals possibly.Theoretical calculation on chemical bonds in crystal structures of three minerals is carried out, finding that the bond length, bond energy, coulomb force, percentage and polarity of ionic bond and bonding strength determine the breaking level of Mn+—O2- when minerals dissociate in flotation system, and the breaking level of Mn+—O2- in crystal structures of three sulfate minerals is closed related with floatability. As to celestite and barite, The Ba-O, Sr-O bonds break largely and much Sr2+、Ba2+ exposing on the surfaces, which can generate chemical reaction with sodium oleate, and chelating reaction with salicylhydroxamic acid, so celestite and barite have good floatability in the systems of sodium oleate and salicylhydroxamic acid.The bond Ca-O in gypsum structure is more difficult to break, and Ca2+ exposes very little, so the electronegativity on the surface of gypsum is higher, which leads to a good floatability in the flotation system of lauryl amine, better than in the sodium oleate and salicylhydroxamic acid flotation systems. The results of computer aided calculation are accordant with the flotation experiments results, showing that the reaction energy of mineral and reagent changes more, the floatability is better.更多还原