新疆雅满苏磁铁矿中硅的赋存状态研究

发布时间：2018-02-04 03:37

本文关键词： 磁铁矿穆斯堡尔谱雅满苏铁矿元素赋存状态新疆　出处：《东华理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：磁铁矿广泛出现于各种类型的岩石中,具有反尖晶石结构。由于在磁铁矿晶格中常发育类质同象,其晶格内可赋存多种杂质元素。Si与Fe无论是从离子半径还是从电子的获取能力上均存在较大区别,然而无论是利用电子探针分析还是湿化学法,很多研究均表明:磁铁矿晶体中含有一定数量的硅。目前,硅是否类似于Al、Mg、Ti等元素,以类质同象的方式进入磁铁矿晶格目前尚不明确。已有研究表明Si在磁铁矿中的含量对磁铁矿的生成环境(成矿环境)有较大的指示意义:热液环境中生成的磁铁矿晶体中的SiO2的含量可达6.19wt%,而在一些正岩浆型的磁铁矿中,SiO2的含量常常低于电子探针的检出限。本文对杂质元素(Co,Si,Ca,Cu,Ni,Mg,Ti,Mn)在磁铁矿中赋存状态总结的基础上,使用电子探针、X射线衍射、透射电镜和穆斯堡尔谱等技术方法,研究来自新疆雅满苏矽卡岩型磁铁矿,尝试阐明磁铁矿晶体中Si的可能赋存状态,研究结果如下:(1)电子探针研究表明:新疆雅满苏磁铁矿含有一定数量的硅,Si的含量与Fe3+含量呈明显的负相关线性关系,指示Si进入磁铁矿晶格内。值得注意的是,高分辨率透电镜及能谱分析显示,磁铁矿中存在硅酸盐的包裹体;(2)X射线衍射测试显示:测试样品的晶胞参数较磁铁矿相比略有偏小,由于Si和Fe离子半径以及替代含量的差异,其晶胞参数分别为8.392?和8.374?,硅进入磁铁矿的晶格是导致其晶胞参数减少的最主要原因,类质同象是磁铁矿中硅的主要赋存形式;(3)穆斯堡尔谱的相关数据研究证明:指示Si替换了四面体上Fe3+的位置,随着类质同象替代愈加广泛,其A位上同质异能位移、四极分裂参数略有增大,磁超精细场参数略有减少;B位上同质异能位移和磁超精细场参数略有减少;A位和B位的半高宽均略有减少;A/B面积比略有减小。
[Abstract]:Magnetite is widely found in various types of rocks with antispinel structure. Many impurity elements, I. e., Si and Fe in the lattice, are different from Fe in both ion radius and electron acquisition ability. However, both electron probe analysis and wet chemical method are used. Many studies have shown that there is a certain amount of silicon in magnetite crystals. It is not clear to enter the magnetite lattice in the form of similar material and image at present. It has been shown that the content of Si in magnetite has a great indicative significance for the environment of magnetite formation (metallogenic environment): the magnetic generation in hydrothermal environment. The content of SiO2 in the crystal of iron ore can reach 6.19 wt.The content of SiO2 in some magnetite of magmatic type is often lower than the detection limit of electron probe. By means of electron probe X-ray diffraction, transmission electron microscope and Mossbauer spectroscopy, this paper studies the possible state of Si in magnetite crystals from Yamensu skarn type magnetite in Xinjiang, and tries to elucidate the possible state of Si in magnetite crystals. The results are as follows: the electron probe study shows that there is a negative linear relationship between the content of Si and the content of Fe3 in Yamensu magnetite in Xinjiang, indicating that Si enters the lattice of magnetite. High resolution TEM and EDS analysis showed that the crystal cell parameters of the samples were slightly smaller than those of magnetite samples, due to the difference of Si and Fe ion radius and the substitution content of Si and Fe ions, and the X-ray diffraction analysis of the inclusions containing silicates in magnetite samples showed that the unit cell parameters of the samples were slightly smaller than those of magnetite samples. The cell parameters were 8.392? And 8.374? The lattice of silicon entering magnetite is the main reason for the decrease of unit cell parameters. The data of the Mossbauer spectrum show that Si replaces the position of Fe3 on tetrahedron. With the more extensive substitution of homomorphism, the isomorphic displacement at position A and the quadrupole splitting parameter increase slightly. The parameters of the magnetic hyperfine field decrease slightly the isomorphic displacement on the B position and the half-maximum width of the magnetic hyperfine field parameters decrease slightly both at position A and position B the area ratio of A / B decreases slightly.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P578.46

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