P507-HCl-酒石酸体系萃取分离轻稀土元素的基础研究

发布时间：2018-02-08 19:29

本文关键词： P507 酒石酸分配比分离系数萃取容量　出处：《天津大学》2015年硕士论文　论文类型：学位论文

【摘要】：稀土行业的发展愈来愈快,其应用也变得日趋广泛,稀土元素已成为各国的重要战略资源。分离稀土元素的方法种类繁多,如今我国工业分离高纯单一的稀土元素的方法有很多,绝大多数采用皂化的P204或P507等酸性磷萃取剂分离稀土元素,该方法虽然萃取性能好,但有一个明显的弊端就是会产生大量的氨氮废水,对环境污染较为严重。针对此缺点,本论文通过研究在有机萃取剂P507中加入一种名为酒石酸的配合剂,研究了在该体系下的三个重要参数分配比、分离系数、萃取饱和容量与酸度、酒石酸浓度和稀土浓度之间的相互关系,并与不含酒石酸的P507—盐酸体系的分离效果进行对比,最后研究了该体系下轻稀土从有机相到水相的反萃过程。本文采用单级萃取实验,研究了在不同的稀土浓度、酸度和酒石酸浓度条件下,该体系四种轻稀土元素的分配比、分离系数和萃取饱和容量的变化情况。主要结论如下:当料液酸度PH值控制在1.0、酒石酸浓度和稀土浓度均为0.25mol/L、萃取剂浓度为1.5mol/L时,分配比以及分离系数达到最大,分别达到DLa=0.1966、DCe=0.7781、DPr=1.6215和DNd=2.4899,βCe/La=4.08、βPr/ce=1.98和βNd/Pr=1.62;并且随着酒石酸浓度的升高,P507萃取四种轻稀土的饱和容量也逐渐增大,可以达到29.7g/L,比单一盐酸体系提高约50%。最后做了稀土的反萃实验,串级反萃模拟实验结果表明,当反萃盐酸浓度5mol/L,在相比O/A=2:1下,经过5级反萃后,稀土的反萃率可达到98%以上,并且出口稀土浓度较大,出口酸度较低,负载有机相中残留的酸量较小,约为0.8mol/L,反萃效果好。P507—HCI—酒石酸体系无需皂化过程,工艺简单,萃取效果较好、分离系数高、反萃容易。由于该萃取体系不需要加入皂化剂,可大大降低氨氮废水的产生,同时节约了成本,是一项颇具特色的稀土萃取分离工艺。
[Abstract]:The rare earth industry is developing more and more rapidly, and its application is becoming more and more extensive. Rare earth elements have become an important strategic resource in various countries. There are many methods of separating rare earth elements. Nowadays, there are many industrial methods for separating high purity and single rare earth elements in our country, most of them are separated by saponification acid phosphorus extractants such as P204 or P507, although this method has good extraction performance. However, there is an obvious drawback that a large amount of ammonia-nitrogen wastewater will be produced, which will cause serious environmental pollution. In view of this shortcoming, this paper studied the addition of a complex agent called tartaric acid to the organic extractant P507. The relationship between the distribution ratio of three important parameters, separation coefficient, extraction saturation capacity and acidity, tartaric acid concentration and rare earth concentration in this system was studied, and the results were compared with those of P507-hydrochloric acid system without tartaric acid. Finally, the stripping process of light rare earth from organic phase to water phase in this system was studied. The distribution ratio of four light rare earth elements in this system was studied under different rare earth concentration, acidity and tartaric acid concentration by single stage extraction experiment. The main conclusions are as follows: when the pH value of feed liquid is 1.0, the concentration of tartaric acid and rare earth is 0.25 mol / L, and the concentration of extractant is 1.5 mol / L, the distribution ratio and separation coefficient reach the maximum when the pH value of feed solution is 1.0, the concentration of tartaric acid and rare earth is 0.25 mol / L, and the concentration of extractant is 1.5 mol / L. The saturated capacity of four kinds of light rare earths was gradually increased with the increase of tartaric acid concentration, and the saturation capacity of four kinds of light rare earths was gradually increased, reaching 29.7 g / L, which was about 500.5% higher than that of the single hydrochloric acid system. Finally, the extraction capacity of 尾 Pr/ce=1.98 and 尾 NdR was 4.08, 尾 Pr/ce=1.98 and 尾 Ndrr 1.62with the increase of the concentration of tartaric acid, and the saturation capacity of the four kinds of light rare earths was gradually increased to 29.7 g / L, which was about 50g / L higher than that of the single hydrochloric acid system, with the increase of the concentration of tartaric acid. The simulation results of cascade stripping experiments show that when the concentration of hydrochloric acid is 5 mol / L, when compared with O / A 2: 1, the stripping rate of rare earth can reach more than 98%, and the export concentration of rare earth is higher and the export acidity is lower than that of O / A (2: 1). The residual acid content in the loaded organic phase is about 0.8 mol / L, the stripping effect is good. P507-HCI- tartaric acid system does not need saponification process, the process is simple, the extraction effect is better, the separation coefficient is high, the stripping is easy, because the extraction system does not need to add saponification agent, It can greatly reduce the production of ammonia nitrogen wastewater and save the cost. It is a characteristic rare earth extraction and separation process.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ133.3;TQ028.32

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