有机相中稀土的反萃性能及微纳米颗粒的形成与抑制

发布时间：2018-05-30 02:32

本文选题：草酸稀土 + 溶解度　；参考：《南昌大学》2017年硕士论文

【摘要】：从稀土有机相中反萃稀土是分离稀土的必要环节,也是制备微纳米材料的一种新方法。随着高技术领域环保要求的不断提高,寻求新的绿色环保反萃技术已经成为当前稀土行业的研究热点。本论文研究了两种稀土有机相的反萃性能,重点关注反萃过程中微纳米颗粒的可控形成与消除方法,以及在改善分相性能和制备微纳米材料上的应用性能。高纯稀土沉淀废水中含有大量的盐酸、草酸和少量稀土,本研究拟用沉淀法去除其中的大部分草酸,获得可以从P507萃取有机相中反萃稀土的盐酸。为了实现废水的循环利用,达到绿色工艺要求,需要确定反萃酸中残留草酸的允许浓度以及保证反萃过程不析出沉淀的具体方法。为此,系统地研究了15种稀土草酸盐在不同盐酸和稀土浓度下的溶解度变化规律。结果表明:随稀土浓度的增大,稀土草酸盐的溶解度先是由于同离子效应而急剧减弱,当稀土浓度范围在0.05-0.10 mol/L时草酸稀土的溶解度最低,超过这一浓度,草酸稀土溶解度随稀土浓度的增大而增大。与此同时,随盐酸浓度的增大草酸稀土的溶解度也一直增大。因此,可以通过调控溶液中的稀土和盐酸浓度来调控草酸稀土沉淀的溶解度,防止反萃过程形成沉淀。为此,先用稀土沉淀法去除溶液中的过量草酸,滤出的溶液中加入盐酸至4-6mol/L后即可用于稀土的反萃;通过一级、多级错流和多级逆流等反萃方式,证明所得的回收酸可以用作稀土的反萃酸,不会影响分相性能。配合物溶胶-凝胶法和燃烧法,以及醇盐水解法均可合成稀土及其复合氧化物纳米粒子。但由于消耗大,废气多,且醇盐对水又十分敏感等问题而难以工业化。基于稀土水杨酸甲酯配合物的水解特征,本研究提出通过弱配位化合物的水解来制备微纳米稀土材料的方法。首先在乙醇或乙酸丁酯中合成水杨酸酯配合物,通过监测有机相的紫外可见光谱,研究了水对有机相中稀土的反萃性能。采用等摩尔系列法测定了水杨酸甲酯配合物的组成和稳定常数。结果表明:稀土离子Y3+和水杨酸甲酯是以1:1发生配位,其组成为YMS;而铝离子Al3+和水杨酸甲酯是以3:2发生配位的,其组成为Al3MS2。通过作图法求得Y-MS的解离度为0.225,稳定常数为7.65x104(lg K=4.88);Al-MS的解离度为0.258,稳定常数为2.72x103(lg K=3.43)。利用稀土水杨酸甲酯配合物水解后形成的溶胶,制备得到纳米级颗粒的Er掺杂YAG上转换发光材料粉体。获得纯YAG相的煅烧温度为1000℃,比传统的高温固相法降低了600℃,制备的YAG粉体尺寸分布均匀,分散性好,为球形颗粒,单颗粒粒径约为80nm。这种方法可作为一种全新有效的YAG微纳米粉体制备技术。
[Abstract]:Re extraction of rare earth from rare earth organic phase is a necessary link for the separation of rare earth. It is also a new method for the preparation of micro nano materials. With the increasing requirements of environmental protection in the field of high technology, the search for new green extraction technology has become a hot spot in the rare earth industry. This paper studies the stripping performance of two kinds of rare earth organic phases. The controllable formation and elimination of micro nano particles in the process of stripping, as well as the application performance of the phase separation performance and the preparation of micronanomaterials are also concerned. The high purity rare earth precipitation wastewater contains a large amount of hydrochloric acid, oxalic acid and a small amount of rare earth. This study is intended to remove most of the oxalic acid by precipitation method and can be extracted from P507 In order to realize the recycling of waste water and achieve the requirements of green process, the permissible concentration of the residual oxalic acid in the stripping acid and the method of ensuring the precipitation in the process of stripping are determined in order to realize the recycling of waste water and to ensure that the precipitation in the stripping process is not precipitated. Therefore, the solubility changes of 15 rare earth oxalates in different concentrations of hydrochloric acid and rare earth are systematically studied. The results showed that the solubility of rare earth oxalate decreased rapidly with the increase of rare earth concentration, and the solubility of rare-earth oxalate was the lowest when the concentration range was 0.05-0.10 mol/L. The solubility of rare-earth oxalate increased with the increase of rare-earth concentration. Meanwhile, the oxalic acid was dilute with the concentration of hydrochloric acid. The solubility of soil is also increasing. Therefore, the solubility of rare earth precipitation can be regulated by controlling the concentration of rare earth and hydrochloric acid in the solution to prevent the formation of precipitate from the reverse extraction process. It is proved that the recovered acid can be used as the reextraction acid of rare earth, and it does not affect the phase separation performance. The complex of rare earth and its composite oxide nanoparticles can be synthesized by the sol-gel method and combustion method, and the solution of alcohol salt solution. But the waste is large, the exhaust gas is much more, and the alcohol is very sensitive to water. Based on the hydrolysis characteristics of rare earth Methylis salicylas complexes, a method for the preparation of Nanoscale Rare Earth Materials by the hydrolysis of weak coordination compounds was proposed in this study. First, the synthesis of salicylate complexes in ethanol or butyl acetate was synthesized. The organic phase was studied by monitoring the UV visible spectrum of organic phase. The composition and stability constants of the Methylis salicylas complexes were determined by the equimolar series method. The results showed that the rare earth ions Y3+ and Methylis salicylas were coordinated with 1:1, and their composition was YMS, while the aluminum ions Al3+ and Methylis salicylas were coordinated by 3:2, and the composition of the composition was Al3MS2. through the mapping method to obtain Y-MS. The degree of dissociation is 0.225, the stability constant is 7.65x104 (LG K=4.88), the dissociation degree of Al-MS is 0.258, the stability constant is 2.72x103 (LG K=3.43). Using the sol formed after the hydrolysis of the rare earth Methylis salicylas complex, the Er doped YAG upconversion luminescent material powder is prepared. The calcining temperature of the pure YAG phase is 1000, compared with the traditional one. The high temperature solid phase method is reduced by 600 degrees C. The size distribution of YAG powders is uniform, the dispersion is good, the particle size is spherical, and the single particle size is about 80nm. can be used as a new and effective YAG micro nano powder preparation technology.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O658.2

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