【作者】 陈伟；

【导师】 杨运泉；

【作者基本信息】 湘潭大学 ， 化学工程与技术， 2016， 硕士

【摘要】 工业废水中通常含有大量的重金属离子,因其本身的污染特性给环境所带来的巨大危害而受到社会与国家的高度重视与关注。但是,传统的废水处理技术花费高,过程繁杂且废水较难地得到有效的治理,因此,开发出一种经济节约型以及环境友好型的废水处理技术势在必行。液膜分离技术是一种新型的分离富集技术,由于其分离效果好、传质速率快、选择性强以及试剂用量少等优点从而被广泛的运用在工业废水重金属离子的处理研究。本文采用乳化液膜法对硫酸盐溶液中的钴离子和镍离子进行分离研究。乳状液膜主要由溶剂(正庚烷)、表面活性剂(Span80)、载体(Cyanex272,P272)、膜添加剂(液体石蜡)和内水相(硫酸)组成。由于钴、镍在理化性质上的相似性,将其进行分离的工艺是湿法冶金中较困难的工艺操作之一。目前,钴镍分离主要采用的分离方法包括有化学沉淀法和溶剂萃取法。化学沉淀法主要适用于钴镍化合物存在溶度积差异的情况,但化学沉淀法的主要问题是:钴产品(钴渣)中的镍含量较高,产品纯度低,常需进一步的深度处理和提纯。相比较来说,溶剂萃取比化学沉淀法具有一定的优越性,更加能够满足工业需求。本文采用乳化液膜法对钴镍进行分离处理,同时研究了乳化液膜的成分体积比、搅拌速度、载体浓度以及内外相体积比对钴镍萃取分离的影响。通过建立数学模型,深入地解释了乳化液膜的传质机理,同时也能够通过数学模型轻松地了解硫酸盐溶液中离子浓度随时间的变化。通过本文的研究,可以得到钴镍分离的最佳分离条件:φ(P272)=5.0%(V/V),φ(Span80)=5.0%(V/V),转速为400转/分,外水相与内水相体积比为20(V/V),搅拌时间1200s。在此工艺条件下,钴离子的迁移率达到98.0%,而镍离子的迁移率只有9.0%,钴、镍的分离度达到11倍左右,从而实现了钴离子和镍离子的有效分离。在对镍采用乳化液膜法单独萃取时,其最佳的分离条件:φ(PC88A)=6%(V/V),φ(Span80)=5.0%(V/V),转速为400转/分,外水相与内水相体积比为16(V/V),搅拌时间为900s。在此工艺条件下,镍离子的迁移率达到99.98%,满足工业废水的排放要求。本实验研究过程中所取得的各个工艺参数望今后能够成为工业试验的依据和参考。更多还原

【Abstract】 A large number of industrial wastewater containing heavy metal ions in general, because of the pollution of their own characteristics to the enormous harm the environment and received great attention and concern of society and nation.However, the traditional wastewater treatment technology is expensive, and the process is complicated and the wastewater is difficult to be effectively treated. Therefore, it is imperative to develop a kind of economical and environmentally friendly wastewater treatment technology.Liquid membrane separation technology is a new separation and enrichment technique, due to its separation effect is good, fast mass transfer rate, selectivity and low energy consumptiong,etc, so it was widely using in the study on the treatment of industrial wastewater containing heavy metal ions.Cobalt and nickel ions in sulphate solutions were separated by emulsion liquid membrane method(ELM) in this paper.The ELM system consists of a solvent(n-Heptane), a surfactant(Span80), a carrier(Cyanex272, P272), a kind of film formation additive(liquid paraffin) and an internal phase of sulfuric acid solution.Due to the similarity of cobalt and nickel in physical and chemical properties, the separation process is one of the more difficult process in Hydrometallurgy. At present, the separation methods of cobalt and nickel mainly include chemical precipitation method and solvent extraction method.Chemical precipitation method is mainly applied to cobalt and nickel compounds when there are some differences in the solubility product.However, the chemical precipitation method have some problems,for example the content of nickel in cobalt products is high, the purity of product is low, and it is often needed to be further processed and purified.In comparison, solvent extraction has a certain advantage than chemical precipitation method, more able to meet the demand of industrial needs.In this paper, the separation and treatment of cobalt and nickel by emulsion liquid membrane method.At the same time, the effects of emulsion liquid membrane composition volume ratio, stirring speed, carrier concentration and internal and external volume ratio on the extraction and separation of cobalt and nickel were studied.Through the establishment of mathematical model, the mass transfer mechanism of emulsion liquid membrane is explained in depth, and the change of ion concentration in sulfate solution can be easily understood by mathematical model.The optimal separation conditions for the separation of cobalt and nickel can be investigated through the study of this paper.Under the conditions of φ(P272) =5.0%( V/V),φ(Span 80) =5.0%( V/V), stirring speed of 400 rpm and volume ratio of external phase to internal phase of 20, Stirring time 1200 s,the transfer ratio of the cobalt ion could reach to 98.0 % and that of the nickel ion was only less than 9.0 %. The separation ratio of cobalt to nickel is about 11.0:1.0.so the effective separation of cobalt ion and nickel ion was achieved.When the emulsion liquid membrane was used to separate the nickel.The optimal separation conditions for the separation of nickel can be investigated. Under the conditions of φ(PC88A) =6.0%( V/V),φ(Span 80) =5.0%( V/V), stirring speed of 400 rpm and volume ratio of external phase to internal phase of 16, Stirring time 900 s,the transfer ratio of the nickel ion could reach to 99.98 %,which meet the discharge requirements of industrial waste water.All the technological parameters obtained in this study can be the basis and reference for industrial experiment in the future.更多还原