液膜法分离钴和镍

钻、镍的分离一直受到关注，人们先后利用离子交换法［’‘、色谱法［’‘、苹取法「’‘等方法对它们在水溶液中共存时进行了分离．本文利用液膜法将共存的微量钻、镍一步分离开，同时富集了钻离子．利用液膜富集和分离钻、镍，大量工作是针对它们的富集；对其实施分离，报道甚少［‘·’‘，且分离效果不够满意．将EDTA作为掩蔽剂应用于钻、镍的分离，尚未见报道·仪器为721型分光光度计（上海第三分析仪器厂），PHS－ZC精密酸度计（上海雷磁仪器厂）．试剂为2一乙基已基单2一乙基己基磷酸酯（P507，中国科学院上海有机化学研究所），…     

Separation and concentration of cobalt from ammoniacal solutions containing cobalt and nickel by emulsion liquid membranes using 5,7-dibromo-8-hydroxyquinoline (DBHQ)

The separation and concentration of cobalt from ammoniacal solutions containing nickel and cobalt by an emulsion liquid membranes (ELMs) using 5,7-dibromo-8-hydroxyquinoline as extractant has been presented. Membrane solution consists of a diluent (kerosene), a surfactant (Span 80), a modifier (tributylphosphate), and an extractant (DBHQ). Very dilute sulphuric solution containing EDTA as complexing agent, buffered at pH 5.0, has been used as a stripping solution. pH of ammoniacal feed solution containing cobalt and nickel was adjusted to 9.0 with hydrochloric acid. The important variables governing the permeation of cobalt have been studied. These variables are membrane composition, pH of the feed solution, cobalt and nickel concentrations of the feed solution, mixing speed, surfactant concentration, extractant concentration, EDTA concentration and pH of the stripping solution, and phase ratio. After the optimum conditions had been determined, it was possible to selectively extract 99.0% of cobalt from ammoniacal feed solution containing Co²⁺ and Ni²⁺ ions. The separation factors of cobalt with respect to nickel, based on initial feed concentration, have experimentally found to be of as high as 247.5 for about equimolar Co–Ni feed solutions.     

Separation of large amounts of iron(III) from cobalt,nickel, and aliminum by combined ion exchange-solvent extraction

A method is described for the cation-exchange separation of large amounts of iron(III) from cobalt, nickel, and aluminium. On the strongly acidic Dowex 50-X8, iron(III) is not adsorbed from an 80% tetrahydrofuran-20% 3 M hydrochloric acid mixture, while cobalt, nickel, and aluminium are retained; a quantitative separation is thus possible. Cobalt and nickel or aluminium are then separated by elution with 90% tetrahydrofuran-10% 6 M hydrochloric acid. In these mixtures combined ion exchange-solvent extraction appears to occur; both ion exchange and liquid-liquid extraction are. effective simultaneously.     

Liquid chromatography of palladium and non-ferrous metal chelates with 1-(2-pyridylazo)-2-naphthol

1-(2-Pyridylazo)-2-naphthol has been used for extraction concentration of palladium, copper, cobalt and nickel from aqueous solutions and subsequent separation of the chelates obtained, by means of high-pressure liquid chromatography. A technique for determining microamounts of palladium in aqueous solutions in the presence of 100-fold ratio of copper and 80-fold ratio of cobalt has been developed.     

Extractive separation of Cu<Superscript>2+</Superscript>–Co<Superscript>2+</Superscript> and Ni<Superscript>2+</Superscript>–Co<Superscript>2+</Superscript> mixtures using <Emphasis Type="Italic">N</Emphasis>-salicylideneaniline

A study on the extraction of copper(II), cobalt(II), and nickel(II) from solutions containing ions of both metals with N-salicylideneaniline(SAN) in chloroform has been realized. Distribution of the metal ions in wide range of pH has been studied. Extraction of copper(II) was always favored over that of cobalt(II). Extraction of copper(II) from binary metal solution is selective and it can be quantitatively separated from cobalt(II). The equilibrium constant of the extraction of cobalt and nickel from an aqueous solution containing both metals using SAN were evaluated. The separation factors for cobalt and nickel were expressed as a function of the distribution of nickel and cobalt. From these results, salicylideneaniline is an adequate extractant for extractive separation of such mixtures.     

Investigation and characterization of PVA-g-AAc/Zol membranes for possible practical use in separation processes

Poly(vinyl alcohol) films were grafted with two monomers (acrylic acid and N-vinyl imidazole) using the gamma irradiation technique. The melting temperature (T_m) and glass transition temperature (T_g) of the grafted membranes were determined with respect to the grafting yield. The ability of these membranes to separate cobalt from nickel has been investigated. The diffusion of cobalt and nickel ions from the feed compartment to the receiver compartment depends on the grafting yield and the pH of the feed solution. Cobalt ions do not diffuse through the membrane when the pH of the feed solution is >4.5. Thus, the prepared membranes could be considered for the separation of cobalt ions from nickel ions. The temperature of thermal decomposition of pure PVA-g-AAc/Zol membrane, PVA-g-AAc/Zol membranes containing cobalt ions, and PVA-g-AAc/Zol membranes containing nickel ions are determined using TGA analyzer; it was shown that the presence of cobalt and nickel increases the decomposition temperature. Also the membranes bonded with cobalt ions are more stable than the membranes containing nickel ions.     

Anion-exchange separation of cobalt from nickel

An anion-exchange method has been developed for the separation of cobalt from nickel, based on the observation that from a malonic acid solution containing sodium nitrite, cobalt is preferentially adsorbed by the exchanger but nickel passes through. The cobalt is eluted with 2M ammonium chloride in dilute ammonia solution. Prom an ammonium malonate solution containing chloride and nitrate, cobalt is quantitatively electro-deposited on a platinum cathode to give a bright, adherent deposit. Nickel is deposited from a solution of similar composition.     

Electrodeposition of mesoporous semimetal and magnetic metal films from lyotropic liquid crystalline phases

Mesoporous semimetal bismuth film and magnetic metal nickel and cobalt thin films have been electrodeposited from hexagonal or lamellar structured lyotropic liquid crystalline phases with polyoxyethylene surfactant. The liquid crystalline templates are characterized by low-angle X-ray diffraction (XRD) and polarized-light optical microscopy (POM). The metal films are characterized by low-angle and wide-angle XRD, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The magnetic measurements on the mesoporous nickel and cobalt films are shown to have higher coercivity (Hc) than the nonporous polycrystalline films.     

Studies of modified carbon nanotubes by means of thermogravimetry Q-TG and sorptometry techniques

The paper presents the physicochemical (adsorption and porosity) properties of closed carbon nanotubes, opened through the action of an oxidizing acid and modified with metal ions of nickel, cobalt, and iron/cobalt. The carbon nanotubes were prepared via the oxidation process by means of 65 % nitric acid and/or nickel and cobalt nitrates dissolved with 65 % nitric acid. Using special thermogravimetry Q-TG and sorptometry methods physicochemical properties of pure and modified nanotube surfaces were investigated. A numerical and analytical procedure for the evaluation of heterogeneous properties (adsorption capacity, statistical number of adsorbed liquid layers, desorption energy distribution functions) on the basis of liquid thermodesorption Q-TG from the sample surfaces under the quasi-equilibrium conditions are presented. The calculations of the specific surface areas, pore size and volume, and fractal dimensions of carbon nanotubes were made from sorptometry data.     

Coulometric determination of nickel and cobalt

A method has been developed for the successive determinations of nickel and cobalt by controlled potential coulomctric analysis with a. mercury cathode, using an aqueous pyridine electrolyte, Quantitles of the metals from about 10 to l00 mg per 100 ml are determinable with an average error of ±0.5 mg. Because this controlled potential electrolysis technique produces a clean separation of nickel and cobalt it can be used for preparing nickel-free cobalt compounds and cobalt-free nickel compounds.     

电感耦合等离子体质谱法(ICP-MS)测定镍钴锰三元氢氧化物中铅

研究了用电感耦合等离子体质谱法（ICP-MS）测定镍钴锰三元素氢氧化物中铅含量的测定方法。选择了仪器的最佳测量条件、元素测定的质量数,进行了基体元素的干扰等实验。方法测定结果准确、可靠,测定下限小于0.00005%,样品加标回收率在99.2%~101.0%。方法的建立为控制镍钴锰三元素氢氧化物中铅提供了检测依据。     

Solvent extraction in hydrometallurgy: the role of organophosphorus extractants

Solvent extraction (SX) has come to be one of the most important separation processes in hydrometallurgy. Phosphorus-based extractants have proved to be of particular importance, especially for the separation of cobalt from nickel. However it was not until the dialkyl phosphinic acid reagent, CYANEX 272, and its dithio analogue CYANEX 301, became available that liquors containing very low Co:Ni ratios of at least 1:40 to even >1:100 could be treated. This has opened the way to the direct application of SX for the separation of Co from Ni in liquors derived from the leaching of nickel mattes from the smelting of nickel sulphide ores and from the pressure acid leaching of nickel laterite ores. This paper describes the development of the range of Cytec extractants and, in particular, discusses the development of their application for the separation of cobalt from nickel. Examples of actual industrial operating plants will also be given and individual flowsheets discussed.     

Electrodialytic separation of cobalt(II) and nickel(II) using liquid membranes based on tri-n-octylamine and trialkylbenzylammonium chloride

Electrodialytic separation of Co(II) and Ni(II) in the course of their transfer from 3–4 M HCl solutions into dilute solutions of various acids using liquid membranes that contain anion-exchange carriers was studied. The influence exerted on the metal transport rate and separation efficiency by the compositions of the feed and receiving aqueous solutions and of liquid membranes and by the electrodialysis current density was examined. Under optimal conditions, in metal recovery from a solution containing an equimolar mixture of 0.01 M CoCl₂ and NiCl₂, the separation factor β_Co/Ni is 147; when nickel in the feed solution is in excess, it reaches 330, and when cobalt(II) is in excess, it exceeds 400.     

Anion-exchange separation of iron,cobalt and nickel

From 90% acetone-10% 6 M hydrochloric acid medium, cobalt and nickel are strongly adsorbed on the anion-exchange resin Dowex I-X8; iron is not adsorbed and can thus be separated from cobalt and nickel. Cobalt and nickel are then separated by elution with 70% acetone-30% 2 M hydrochloric acid; nickel is eluted before cobalt. The method can be applied to the determination of nickel and cobalt in materials with high iron content such as steels ; compleximetric titrations are used for the final step.     

Simultaneous Preconcentration of Copper,Nickel and Cobalt In Water By Coprecipitation-Flotation For Electrothermal Atomic Absorption Spectrometry

Abstract

A method is described for the simultaneous flotation separation and determination of μg-levels of copper (II), nickel (II) and cobalt (II) in water. Copper, nickel and cobalt in a 1000-ml sample of water are coprecipitated with hydrated zirconium oxide at pH 9.1±0.1. The precipitate is floated with the aid of a surfactant solution and small air bubbles, separated and dissolved in dilute hydrochloric acid. The contents of these elements are determined by electrothermal atomic absorption spectrophotometry. The method is applied to the determination of low μg/1 levels of copper, nickel and cobalt in fresh water.     

On-line separation and preconcentration in flow injection analysis

Various improvements in flow-injection systems involving on-line separation and preconcentration by gas diffusion, ion-exchange and liquid—liquid extraction are reviewed and their merits are discussed. On-line preconcentration systems based on gas diffusion are described for the spectrophotometric determination of cyanide, fluoride and ammonia. Different gas/liquid separation devices for hydride-generation and cold-vapour atomic absorption spectrometry (a.a.s.) are compared. Systems are outlined for on-line column preconcentration of cobalt, nickel, vanadium, beryllium and cerium for inductively-coupled plasma/atomic emission spectrometry, and for combinations of column preconcentration with hydride-generation and cold-vapour a.a.s for the determination of ultratrace selenium and mercury. An on-line liquid—liquid extraction/flame a.a.s. system capable of achieving 60-fold enhancement for lead is reported; the limit of detection is 0.02 μg ml^?.     

The determination of aluminum,nickel, cobalt,copper, and iron in alnico

A method has been developed for the determination of the major constituents of Alnico based on an anion exchange separation of the chloride complexes and the subsequent determination of aluminum, nickel, copper, cobalt and iron with EDTA. The method is more convenient than conventional classical methods.     

Chemical analysis of manganese nodules: Part IV. Determination of Nickel after Anion-exchange Separation

A method is described for the a.a.s. determination of nickel in manganese nodules after its separation from interfering metals. After dissolution of the sample in a mixture of perchloric and hydrofluoric acids, manganese, iron, cobalt, copper and other elements are adsorbed on the strongly basic anion exchange resin Dowex 1 (chloride form) from 95% ethanol-5% 12 M hydrochloric acid. The nickel passes into the effluent in which it is determined by a.a.s. with an air-acetylene flame. The method was used successfully for the determination of nickel in numerous samples of nodules from the Pacific Ocean.     

Extraction of cobalt (II) and nickel (II) by a solvent impregnated resin containing bis(2,4,4-trimethylpentyl)monothiophosphinic acid

In the present work, studies have been conducted on the equilibrium distribution of cobalt (II) and nickel (II) between aqueous hydrochloric solution and macromolecular resin impregnated with bis(2,4,4-trimethylpentyl)monothiophosphinic acid (Cyanex302, HL). Effects of extraction time, pH values, metal ion concentration, and temperature were investigated. Analysis of the results shows that the extraction of the two metal ions can be explained assuming the formation of metal complexes in the resin phase with a general composition ML ₂. An extraction reaction is proposed and the equilibrium constants of the complexes were determined. The Freundlich isotherm and thermodynamic quantities, i.e., ΔG, ΔH and ΔS were also obtained. Both of the extraction reactions of cobalt (II) and nickel (II) are endothermic ones. The efficiency of the resin in the separation of cobalt (II) and nickel (II) is provided according to the separation factors. Under the experimental conditions employed, pH₅₀ values for cobalt (II) and nickel (II) are 3.76, 5.01, respectively. The logarithmic value of separation factor was calculated as 2.50.     

(Series Editor) Transform Techniques in Chemistry,P.R. Griffiths,D. Hercules (Eds.), in: Modern Analytical Chemistry Series,Plenum, New York,NY (1978), 385 pp. $47.40

Concentration potentials in zinc sulphate, copper sulphate, nickel sulphate and cobalt sulphate solutions across liquid membranes based on myristates and laurates of zinc, copper, nickel and cobalt and caprate and caprylate of copper have been studied in concentration cells in which the liquid membrane separates the two solutions of the same electrolyte. The behaviour of the cell with heavy metal soap liquid ion-exchange membranes becomes more and more nernstian as the number of carbon atoms in the hydrocarbon chain of the fatty acid soap increases. Concentration potential values with copper, zinc, nickel or cobalt soap follow the order of their insolubility in water. The failure to record the theoretical potentials as calculated by Nernst's equation has been explained by considering the transport of water across organic phase by hydrated ions and the dissolution of heavy metal soaps in aqueous solutions. Liquid membranes based on heavy metal myristate soaps when used in concentration cells could measure the activities of zinc, copper, nickel and cobalt ions in the concentration range of 10^?4–10^?1M.