以白云鄂博稀土尾矿为原料制备稀土基掺杂型复合氧化物催化材料的研究

发布时间：2018-04-21 13:22

本文选题：稀土尾矿 + 掺杂型稀土基复合氧化物　；参考：《内蒙古大学》2017年硕士论文

【摘要】：我国超过一半以上的稀土资源来自于内蒙古包头的白云鄂博稀土矿床中,该矿经开采、浮选以及分离处理后会产生铁精矿和稀土尾矿,由于采选工艺落后等因素使稀土尾矿中仍含有部分的可回收资源,例如赤铁矿、独居石和氟碳铈矿等。这些稀土尾矿如无法得到有效利用,会造成极大的资源浪费,并产生重大环境问题,因此急需找到一条合理、可行、绿色、高效的尾矿综合利用途径。与此同时,在化石能源逐渐枯竭、全球环境问题日益突出的今天,加速发展廉价易得的非贵金属氧化物电催化剂是推动清洁、高效的燃料电池走向产业化的必经之路。铁-铈复合氧化物基电催化材料由于其廉价易得、原材料储量大以及良好的催化性能,近年来在燃料电池氧还原催化领域一直备受关注。而稀土尾矿中同时含有Fe,Ce元素以及Al,Mg,Co,K等微量元素,前者可作为催化剂的主要活性组分,后者则以掺杂的方式进入到催化剂中,起到助催化剂的作用,在提升电催化材料的导电率、催化轻度和稳定性方面有着不可多得的天然优势。针对白云鄂博稀土尾矿高值化利用这一重大课题,本文拟将稀土尾矿不经深度分离提纯直接制备稀土基掺杂型复合氧化物催化材料,重点探索稀土尾矿的化学组成、溶液化学、沉淀行为等理化特性,并基于其溶解和沉淀化学,通过调节稀土尾矿酸浸液溶液的pH值,将稀土尾矿中Fe和Ce等富含元素转化为尺寸和形貌可控的稀土基复合氧化物催化材料(Ce02-Fe2O3),而微量元素A1,Mg,Co,K作为助催化剂掺入到稀土基复合氧化物的晶格当中,从而制备得到以稀土基复合氧化物Ce02-Fe2O3为基质、微量元素Al,Mg,Co,K为掺杂离子的掺杂型稀土基复合氧化物催化材料(Ce02-Fe2O3),并系统评价其在燃料电池阴极氧还原反应领域中的电催化性能,以期获得高价值的、具有自主知识产权的稀土尾矿的掺杂型稀土基复合氧化物催化材料,实现其在能源催化转化和环境催化领域的应用。本文第一章为绪论部分,主要综述了稀土尾矿综合利用的现状、燃料电池阴极氧还原反应的电催化剂的研究进展,确立了本文的选题依据,提出了将稀土尾矿不经深度分离提纯直接制备掺杂型稀土基复合氧化物催化材料的稀土尾矿综合利用的新途径。本文第二章以白云鄂博稀土尾矿为研究对象,采用X射线粉晶衍射仪(XRD)和X射线荧光光谱(XRF)等研究方法,深入研究了稀土尾矿的物相与化学成分、溶液化学、溶解剂沉淀行为等特性,通过对稀土尾矿进行球磨、酸浸、沉淀等加工处理,获得了可用于制备掺杂型稀土基复合氧化物催化材料的稀土基复合氢氧化物前躯体。本文第三章以前述所得的稀土基复合氢氧化物前驱体为原料,采用水热/溶剂热方法,通过调节溶液pH值、表面活性剂种类、溶剂类型及其他反应条件,制备了掺杂型稀土基复合氧化物催化材料。利用X射线粉晶衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等表征手段,对掺杂型稀土基复合氧化物催化材料的结构、组成、相态、尺寸和形貌等进行了系统研究,并通过线性扫描、圆盘电极测试等电化学方法对其催化燃料电池阴极氧还原反应的催化性能进行了初步研究。研究发现,通过调控稀土尾矿溶液酸浸pH值获得不同氢氧化物沉淀物并以其为前驱体,使用不同表面活性剂可得到具有不同尺寸和形貌的掺杂型稀土基复合氧化物催化材料。通过优化反应条件,所得掺杂型稀土基复合氧化物催化材料对氧还原反应催化的半波电位可达0.78 V,已经具有了较好的氧还原电催化性能,为稀土尾矿制备高附加值掺杂型稀土基复合氧化物催化材料,实现稀土尾矿的无尾化综合利用提供了一条简便、廉价、高附加值的利用途径。本文第四章对全文进行了总结,并对论文限于时间未完成的研究内容和下一步研究工作进行了展望,为后人开展相关工作提供指导。
[Abstract]:More than half of the rare earth resources in China are derived from the Baiyunebo rare earth deposits in Baotou, Inner Mongolia. After mining, flotation and separation, the ore will produce iron concentrate and rare earth tailings. Due to the backward mining technology, some recoverable resources, such as hematite, monazite and fluorocarbite, are still contained in the rare earth tailings. If the rare earth tailing can not be effectively used, it will cause great waste of resources and produce major environmental problems. Therefore, it is urgent to find a reasonable, feasible, green and efficient way for comprehensive utilization of tailings. At the same time, the rapid development of cheap and inexpensive non expensive in today's increasingly depleted fossil energy and the increasingly prominent global environmental problems. Metal oxide electrocatalysts are the only way to promote the industrialization of clean and efficient fuel cells. The iron cerium oxide based oxide based electrocatalysis materials have attracted much attention in the field of Oxygen Reduction Catalysis in recent years because of their cheap availability, large raw material reserves and good catalytic performance. The rare earth tailings contain Fe at the same time. The Ce element and the trace elements such as Al, Mg, Co, K can be used as the main active component of the catalyst. The latter enters the catalyst in the way of doping, and plays the role of helping the catalyst. It has a rare natural advantage in improving the electrical conductivity of the electrocatalytic materials, and in the light and stability of the catalysis of Baiyunebo rare earth tailing. Using this important topic, the rare earth tailings are prepared without depth separation and purification to direct the preparation of rare earth based compound oxide catalytic materials. The chemical composition, solution chemistry and precipitation behavior of rare earth tailing are focused on, and the pH value of the acid leaching solution of rare earth tailing is adjusted based on its dissolution and precipitation chemistry. The rich elements such as Fe and Ce in rare earth tailing are converted into rare earth based composite oxide catalytic materials (Ce02-Fe2O3) with controllable size and morphology, while trace elements A1, Mg, Co, K are added to the lattice of rare earth based composite oxides as Co catalysts. Thus, the matrix of the rare earth based compound oxide Ce02-Fe2O3 is prepared, and the trace elements Al, Mg, C are obtained. O, K is doped ion doped rare earth based composite oxide catalytic material (Ce02-Fe2O3), and its electrocatalytic performance in the cathode oxygen reduction reaction of fuel cells is systematically evaluated in order to obtain high value rare earth tailings doped rare earth based compound oxide catalytic materials with independent intellectual property rights, and to realize their energy catalysis. The first chapter is the introduction part of this paper, which mainly summarizes the present situation of the comprehensive utilization of rare earth tailing, the research progress of the electrocatalyst for the cathode oxygen reduction reaction of fuel cells, establishes the basis for this paper, and puts forward the direct preparation of the doped rare-earth compound oxygen by the non depth separation and purification of the rare earth tailings. A new way for the comprehensive utilization of rare earth tailings of chemical materials is made. In this paper, the second chapter of this paper is based on the rare earth tailings in Baiyunebo as the research object. The properties of the phase and chemical composition of the rare earth tailings, the chemical composition of the solution, the precipitation behavior of the dissolved agent and so on, are studied by using the rare earth tailings in Baiyunebo as the research object. Rare earth tailings are processed by ball milling, acid leaching, precipitation and other processing. The rare earth based compound hydroxide precursor can be obtained for the preparation of doped rare-earth compound oxide catalytic material. In the third chapter, the rare earth based compound hydroxide precursor is used as the raw material, the water hot / solvothermal method is used to adjust the pH value of the solution. Doped rare-earth matrix composite oxide catalytic materials are prepared by the type of surface active agent, type of solvent and other reaction conditions. The structure, composition, phase state, size and morphology of the doped rare-earth complex oxide catalytic materials are made by means of X ray powder crystal diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The catalytic performance of the cathode oxygen reduction reaction in the catalytic fuel cell was preliminarily studied by linear scanning, disc electrode testing and other electrochemical methods. It was found that different hydroxides precipitates were obtained by adjusting the acid leaching pH value of the rare earth tailing solution and using the different surface activity as precursors. The doped rare-earth matrix composite oxide catalytic material with different sizes and morphologies can be obtained. By optimizing the reaction conditions, the half wave potential of the doped rare-earth matrix composite oxide catalytic material can reach 0.78 V for oxygen reduction reaction. It has better catalytic performance of oxygen reduction and high added value for the rare earth tailings. The doped rare-earth matrix composite oxide catalytic material has provided a simple, cheap and high value-added utilization way to realize the comprehensive utilization of rare-earth tailings, which is cheap and high added value. The fourth chapter of this paper is a summary of the full text, and the research content and the next research work of the paper are prospected for the future generations to carry out the related work for the future generations. Provide guidance.

【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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