微量镍和微量钴的分离富集研究

【作者】 田锋；

【导师】 张锦柱；

【作者基本信息】 昆明理工大学 ， 矿物加工工程， 2007， 硕士

【摘要】 双水相体系萃取是近几年来迅速发展起来的一类新型萃取分离体系。它主要有两种类型：高聚物／高聚物，高聚物／盐。本文利用的既不是第一种类型，也不是第二中类型，本文利用的是另外一种类型的萃取分离体系：小分子有机物／盐。它是利用水溶性小分子有机物在无机盐存在下可以分成两相，利用物质在互不相溶的两个水相之间分配系数的差异实现分离的方法，使用特定的萃取方法，即可对所需物质进行分离。本文利用乙醇（C₂H₅OH）-盐（（NH₄）₂SO₄）-H₂O双水相体系进行了微量钴和微量镍的分离富集研究，通过反复的摸索、试验，最终确立了最佳的试验条件，该方案可使微量钴的回收率达96％以上，具体完成的工作如下：（1）双水相分相受许多因素的影响，主要包括：无机盐的种类和用量、酸度、小分子有机物的加入量等因素对双水相体系的影响。（2）研究了亚硝基R盐与Co（Ⅱ）的配合物在乙醇-硫酸铵-水双水相体系中的分配行为。通过大量的试验，对影响萃取分离的酸度、萃取剂的用量、盐用量、相比范围、小分子有机物的用量等诸多因素进行了分析，进行了微量钴和微量镍的混合分离实验。（3）对萃取机理进行了初步的研究，通过摩尔比法和连续变化法测定了乙醇相中Co（Ⅱ）与亚硝基R盐的络合物组成。在一定的介质环境中，其络合比为1：3。与此同时，考察了不同类型的表面活性剂对双水相体系中Co（Ⅱ）与亚硝基R盐络合物萃取率的影响。根据试验结果，结合理论分析，初步探讨了在双水相体系中钴的萃取机理。认为在乙醇（C₂H₅OH）-盐（（NH₄）₂SO₄）-H₂O双水相体系中对金属离子的萃取是络合作用、静电引力等多种因素的综合结果。（4）在离子的测定方面，利用亚硝基R盐和丁二酮肟作显色剂，寻求出在乙醇相中和盐水相中对钴和镍互不干扰的分光光度测定方法。通过实验测定了影响络合体系的一些因素，确定了最佳显色条件，充分利用该双水相体系的优点，即不经过反萃即可在上层乙醇相中直接测定。通过对Co（Ⅱ）的分离实验研究，确定了最佳分离条件。在PH=5.7，1.5ml的亚硝基R盐溶液，6ml的95％的乙醇溶液，体系总体积为20ml，加入9g的硫酸铵分相的条件下，成功实现了Co（Ⅱ）的定量分离，96％以上的Co（Ⅱ）富集在乙醇相中。此种方法与以往的传统的溶剂萃取法相比，具有分离效率高、操作简单、价廉、无毒等优点，因此，具有广阔的应用前景。更多还原

【Abstract】 Aqueous two-phase system is a new kind of extraction separation system quickly developed in recently years. It mainly includes two types: polymer/polymer,polymer/salt. This article is not the first kind of type and the second type, This article is other one kind of type extraction separation system: alcohol/salt.Aqueous two-phase extraction is a technique which is used special extraction method and based on the principle that soluble polymer solution can separate two phase in the presence of inorganic salt and the difference of the distribution ratio of matter.The separation and concentration of Co( II) and Ni using alcohol-salt-water aqueous two-phase system were studied. Through continuous explorations and experiments, at last, optimized experiment conditions were decided. The extraction rate of Co surpassed 96%, specifying finished work as follows:(1) There are many factors affecting the phase separation,such as the kind and concentration of inorganic, acidity, and concentration of alcohol, and so on.(2) The distribution behavior of Co(II) and NRS in the alcohol-ammonium and sulphate-water aqueous biphasic system has been investigated. The factors which affect extraction such as acidity, the amounts of extractant and salt, range of phase ratio and the concentration of alcohol were analyzed. Mixing separation experiments of Co( II) were carried out in different amounts of Ni.(3) Mechanism of extraction was studied basically. The composition of Co and NRS was determinated by molar ratio method and continuous variation method. In some acidity condition: Co:NRS=1:3. The affection caused by different surfactants to the extraction rate of Co in two-phase system was investigated. Mechanisms of extraction in aqueous two-phase system was studied on the basis of the experiment results and theoretical analysis. It was believed that metal ion extraction in aqueous two-phase system is the result of complexation reaction,electrostatic effect and hydrogen bonding and hydrophobic bonding.(4) In the ionic determination,the effective spectrophotometry to Co and Ni without interference were found for the use of NRS and DMG in alcohol phase and salt water phase. Through experiments that used the characteristic factor of aqueous two-phase system todeterminate metal ion in upper phase without back extraction, many factors which affect determination were studied, The optimized conditions were decided.Optimized separation conditions were decided through many experiments. It is pH=5.7, 1.5ml NRS solution,6m195% alcohol solution, 9g ammonium and sulphate, 20ml total volume. The system has successfully separated Co from Ni minim. More than 96% Co enrichments in alcohol phase and 93% Ni enrichments in salt water phase. The result of this experimentis satisfactory. Compared with traditional extraction methods, aqueous two-phase extraction has many advantages, such as high extractability, simple operation, low price, low pollution to environment. Therefore, it is a vast useful separation technology.更多还原