稀有金属中微量铌钽的分离富集研究

【作者】 任卿；

【导师】 张锦柱；

【作者基本信息】 昆明理工大学 ， 矿物加工工程， 2006， 硕士

【摘要】 铌钽作为稀有金属中的两种性质非常接近的元素，在自然界中经常共生。不但分离困难，而且通常在用分光光度法测定时由于它们的最大吸收波长接近而导致相互干扰。铌钽的分离方法有几种，但溶剂萃取法一直是铌钽分离的常用方法。实际生产中，主要应用的萃取剂有甲基异丁基酮、磷酸三丁脂、乙酰胺（N，N-二混合烷基乙酰胺）和仲辛醇。其中乙酰胺和仲辛醇是我国自主发明的，其他萃取剂介绍的很少。本文主要采用液-液萃取法，用环己酮为萃取剂，并加入络合物形成剂对微量铌和微量钽进行分离与富集的研究。通过反复的实验，对条件的最优的摸索，最终确立了最佳的分离条件，该方法可以使得萃取达到满意分离效果。本实验具体工作如下：1、对微量铌和微量钽分别进行了单独分离与富集，通过改变不同的萃取及反萃取条件，找出了最佳萃取条件：确定在萃取硫酸浓度为2.5mol／L时，钽的萃取到有机相中达到最大，几乎可以达到100％，同时萃取到该相中的铌约8％。在反萃过程中，稀硫酸溶液首先仅仅只反萃铌，只有用相当多的水稀释洗涤液时，钽方能被其反萃。所以改变反萃液的成分，可以使微量铌钽达到十分细致的分离，获得纯度较高的产品2、实验对络合物形成剂进行了研究，通过比较不同的物质，最终确定了加入NH₄F时分离效果最好，同时通过实验对NH₄F用量对铌钽分离效果影响进行了研究，得到了当其加入量为0.9g／20ml时，微量铌和微量钽的分离效果最好。3、分别对微量铌与微量钽的测定条件进行了研究。找出了包括络合物稳定时间、酸度等方面的最佳条件。在钽测定方面，由于该测定存在显色体系稳定时间短、有少许色淀等缺点，为了达到良好的测定效果，本实验对测定条件进行了反复尝试与校正，最大程度的克服了这些问题，测定效果满意。4、在最后的实验中，又详细的研究了微量铌和钽混合后的分离效果，同时对二者不同比例混合进行了研究，最终给出了一个较好的萃取工艺，这对实际生产更有参考意义。5、探讨了环己酮作为一种中性含氧萃取剂分离微量铌和微量钽的机理，并对详细的反应过程、步骤做了细致的研究和描述表达。更多还原

【Abstract】 As the same group elements in the rare metals. Nb and Ta are usually associated in nature, they are so closed that It is difficult to separate them. The spectrophotometric determination of them is also interfered each other for the most wavelengths of them are so closed.There are several methods in the separation of Nb and Ta, But the resolve extraction is the most common method. The main extractant are Methylisobutyketone （MIBK）, TBP, acetamide and Para-cotanol. Amoung the extractant, acetamide and Para-cotanol are our country’s independent methods. Few other extractant are introduced.The separation and enrichment of Nb and Ta was researched in this paper. Solvent extraction method was applied to separate them, with the extractant of Cydohexanone and the NH4F was used as complex agent, through continuous explorations and experiments, at last the best experiment conditions were decided. We can get a satisfied result. Specify work as follows:1、Trace Nb and Trace Ta were separated each. The best condition of extraction has been found according to varying different conditions. When the acidity of extraction was 2.5mol/L^-1 and complex agent was 0.9g/20ml, the extraction rate of trace Ta can almost reached 100%.At the same time the about 8% trace Nb was extracted to the organic resolve. In the Re-extraction, the low acidity H₂SO₄ just Re-extract the Nb at first ,only the acidity was Diluted by plenty of water,then Ta can be Re-extracted. So change the concentration of the acid, the trace Nb and trace Ta can be separated accurately.2、The complex agent is also investigated. The different salts to the extraction rate are compared, the NH4F, with the use of 0.9g/20ml have the best result.3、The determination condition of trace Nb and trace Ta was studied. Including the stableness of the complexes, acidity of determination and so on. For the Shortages in the determination of trace Ta such as the short time stableness, Color lake, we tried and rectified the determination conditions again and again, finally surmounted these problems asmuch as possible and get a Satisfy result.4、 the result of the mixture of trace Nb and Ta with different Proportion was resrearChed, and get a better Extraction technology at last.5、Discussed the Extraction Mechanisms, Reaction course and steps were researched and described clearly.更多还原