离子型稀土尾矿基陶粒的制备及其性能研究

发布时间：2018-04-01 13:28

本文选题：离子型稀土尾矿　切入点：免烧陶粒　出处：《江西理工大学》2015年硕士论文

【摘要】：离子型稀土矿是我国宝贵的矿产资源,但因其早期开采工艺较落后,导致大量尾矿的产生。这些尾矿在矿区内或周边堆存,不仅占用大片土地,造成了资源的浪费,而且容易引发水土流失,泥石流等地质灾害,对生态环境及安全构成了巨大的威胁。因此如何将稀土尾矿无害化、减量化是当前摆在我们面前的重要课题。为此,本文根据离子型稀土尾矿(以下简称“稀土尾矿”)黏土含量高的特点,采用其制备陶粒以实现该类尾矿的资源化,从而达到无害化与减量化的目的。首先对稀土尾矿的基本性质进行了分析,发现稀土尾矿主要由石英、高岭石等黏土矿物组成,完全符合对于制备多孔陶粒原料的要求。在此基础之上,研究了烧结方法制备陶粒过程,结果表明采用炉内自然冷却能使陶粒具有更好的孔隙结构,且在一定范围内,铝硅比的提高能增大矿物的抗压强度,随着烧结温度与烧结时间在一定范围内增大,陶粒的孔隙结构与抗压强度等性能均能得到提升。并通过条件试验确定了最佳的烧结条件,可以获得吸水率为34.19%、显气孔率55.51%、抗压强度3.62Mpa与体积密度为1.23g/cm3的烧结陶粒。其次,对免烧方法制备陶粒过程进行了研究,比较了钙质激发与碱激发两种免烧方法陶粒制备的效果,结果发现采用钙质激发方法制备的免烧陶粒具有更好的性能,更适合作为废水处理使用的陶粒滤料。通过条件试验确定了免烧陶粒的最佳制备工艺,可获得吸水率为30.28%,显气孔率为49.96%,密度为1.65g/cm3,抗压强度为3.17Mpa的免烧陶粒。对烧结方法与免烧方法制备陶粒的微观结构进行了检测,结构表明,烧结陶粒的内部结构较为均匀、紧密,气孔分布平均,呈三维贯穿,均匀的小气孔构成了疏松多孔的骨架支撑结构;免烧陶粒内部孔隙非常发达,主要为形状不规则的连通大孔,且陶粒内部凹凸不平,说明免烧陶粒内孔隙丰富,比表面积大,两种方法制备的陶粒均符合废水处理陶粒滤料的特性。对烧结陶粒与免烧陶粒的性能进行了检测,结果表明,烧结方法与免烧方法所制备陶粒的强度、吸水率与显气孔率均能达到国家标准的要求,浸出毒性均也符合相关标准。两种陶粒对氨氮废水的处理均显示出了一定的效果,在实际应用中还需要对陶粒进行进一步的改性来提高其废水处理能力。从所制备陶粒产品各项检测的性能来看,以稀土尾矿为原料,采用烧结方法或免烧方法制备陶粒滤料均是可行的。烧结陶粒制备陶粒各项性能略优于免烧方法制备陶粒,但免烧陶粒生产成本较低,应用范围不收限制。
[Abstract]:Ionic rare earth ore is a precious mineral resource in China, but because of its backward mining technology in the early stage, a large number of tailings are produced. These tailings are stored in or around the mining area, which not only occupy a large area of land, but also cause a waste of resources. And it is easy to cause soil erosion, debris flow and other geological disasters, which pose a great threat to the ecological environment and safety. Therefore, how to make the rare earth tailings harmless and reduce is an important subject in front of us. According to the characteristics of high clay content in ionic rare earth tailings (hereinafter referred to as "rare earth tailings"), this paper uses it to prepare ceramsite in order to realize the resource utilization of this kind of tailings. The basic properties of rare earth tailings are analyzed, and it is found that rare earth tailings are mainly composed of clay minerals such as quartz and kaolinite. On the basis of this, the sintering process is studied. The results show that the natural cooling in furnace can make the ceramic have better pore structure and within a certain range. The increase of Al-Si ratio can increase the compressive strength of minerals. With the increase of sintering temperature and sintering time in a certain range, the pore structure and compressive strength of ceramsite can be improved. Sintered ceramsite with water absorption of 34.19, apparent porosity of 55.51, compressive strength of 3.62Mpa and volume density of 1.23g/cm3 were obtained. Secondly, the preparation process of ceramsite by non-sintering method was studied, and the effects of calcium excitation and alkali excitation on the preparation of ceramsite were compared. The results showed that the unsintered ceramsite prepared by calcareous excitation method had better performance and was more suitable for the treatment of waste water. The optimum preparation process of unsintered ceramsite was determined by condition test. The water absorption rate is 30.28%, the apparent porosity is 49.96%, the density is 1.65 g / cm ~ 3, and the compressive strength is 3.17Mpa. The microstructure of the ceramics prepared by sintering method and non-sintering method is tested. The structure shows that the internal structure of sintered ceramsite is uniform and compact. The average distribution of pores was three dimensional, and the uniform small pores formed the loose porous skeleton supporting structure, the internal pores of unburned ceramsite were very developed, mainly composed of irregular connected large pores, and the interior of ceramsite was uneven. The results show that there are abundant pores and large specific surface area in the unsintered ceramsite, and the two methods accord with the characteristics of waste water treatment of ceramic filter material. The properties of sinter and unsintered ceramsite are tested and the results show that, The strength, water absorption and apparent porosity of ceramsite prepared by sintering and non-sintering methods can meet the requirements of the national standard, and the leaching toxicity also meets the relevant standards. The two kinds of ceramsite have a certain effect on the treatment of ammonia-nitrogen wastewater. In the practical application, it is necessary to further modify the ceramsite to improve its wastewater treatment ability. From the performance of various tests of the prepared ceramsite products, rare earth tailings are used as raw materials. It is feasible to prepare ceramic filter material by sintering method or no sintering method. The properties of sinter ceramsite preparation are slightly better than that of no sintering method, but the production cost is lower and the scope of application is not limited.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD98;TQ174.71

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