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Metal solvent extraction

The process used for recovery of uranium from its ores depends on the nature of the ore. All the processes include a leaching step that solubilizes the metal. Solvent extraction is used most frequently for the recovery and... [Pg.512]

Competitive (seven-metal) solvent extraction experiments (water/chloroform) and related bulk membrane transport (water/chloroform/water) experiments have been performed in which each of the four tri-branched ligands as well as their single ring analogues were employed as the extractant/ionophore in the respective chloroform phases [37], In both sets of experiments the aqueous source phases contained an equimolar mixture of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Ag(I) and Pb(II) nitrates and were buffered at pH 4.9. For membrane transport the aqueous receiving phase was buffered at pH 3 under these conditions any transport will be driven by the back transfer of protons. Under the conditions employed, the results from the solvent extraction and the bulk membrane transport experiments clearly paralleled each other -for each ligand system high extraction/transport selectivity for Ag(I) was observed over the other six metal ions present in the respective source phases. [Pg.64]

Similar chemistry, but with a different chelate ligand, is used to purify copper(II). The copper complex is loaded into the organic phase at a pH between 2 and 4, then back-extracted into water as the Cu2+aq ion using dilute sulfuric acid at pH 0. It is recovered as either copper sulfate or, with following electrochemical reduction, copper metal. Solvent extraction involving complex formation is also employed in the separation of cobalt-nickel mixtures. [Pg.260]

Danesi PR, Chiariza R, Colcanan CF (1980) The kinetics of metal solvent extraction. CRC Grit Rev Anal Chem 10(1) 1-126... [Pg.1098]

P. R. Danesi R. Chirizia C. F. Coleman, "The Kinetics of Metal Solvent Extraction" in Critical Reviews in Analytical Chemistry, 1980, B. Campbell Ed. CRC Press, Boca Raton, Florida pp 1. [Pg.121]

Pu (86 years) is formed from Np. Pu is separated by selective oxidation and solvent extraction. The metal is formed by reduction of PuF with calcium there are six crystal forms. Pu is used in nuclear weapons and reactors Pu is used as a nuclear power source (e.g. in space exploration). The ionizing radiation of plutonium can be a health hazard if the material is inhaled. [Pg.318]

Finally, micellar systems are useful in separation methods. Micelles may bind heavy-metal ions, or, through solubilization, organic impurities. Ultrafiltration, chromatography, or solvent extraction may then be used to separate out such contaminants [220-222]. [Pg.484]

The element may be obtained by separating neodymium salts from other rare earths by ion-exchange or solvent extraction techniques, and by reducing anhydrous halides such as NdFs with calcium metal. Other separation techniques are possible. [Pg.181]

Gadolinium is found in several other minerals, including monazite and bastnasite, both of which are commercially important. With the development of ion-exchange and solvent extraction techniques, the availability and prices of gadolinium and the other rare-earth metals have greatly improved. The metal can be prepared by the reduction of the anhydrous fluoride with metallic calcium. [Pg.187]

The cost of dysprosium metal has dropped in recent years since the development of ion-exchange and solvent extraction techniques, and the discovery of large ore bodies. The metal costs about 300/kg in purities of 99+%. [Pg.192]

Another line of analytical use is exemplified by the properties of l-(2-thiazolylazoi-2-naphthol (305), whose complexes with metals may be used for their spectrophotometric and titrimetric determination, as wel] as for their separation by solvent extraction (564, 568, 953-957, 1040). [Pg.154]

Extraction, a unit operation, is a complex and rapidly developing subject area (1,2). The chemistry of extraction and extractants has been comprehensively described (3,4). The main advantage of solvent extraction as an industrial process Hes in its versatiHty because of the enormous potential choice of solvents and extractants. The industrial appHcation of solvent extraction, including equipment design and operation, is a subject in itself (5). The fundamentals and technology of metal extraction processes have been described (6,7), as has the role of solvent extraction in relation to the overall development and feasibiHty of processes (8). The control of extraction columns has also been discussed (9). [Pg.60]

In order to maintain a definite contact area, soHd supports for the solvent membrane can be introduced (85). Those typically consist of hydrophobic polymeric films having pore sizes between 0.02 and 1 p.m. Figure 9c illustrates a hoUow fiber membrane where the feed solution flows around the fiber, the solvent—extractant phase is supported on the fiber wall, and the strip solution flows within the fiber. Supported membranes can also be used in conventional extraction where the supported phase is continuously fed and removed. This technique is known as dispersion-free solvent extraction (86,87). The level of research interest in membrane extraction is reflected by the fact that the 1990 International Solvent Extraction Conference (20) featured over 50 papers on this area, mainly as appHed to metals extraction. Pilot-scale studies of treatment of metal waste streams by Hquid membrane extraction have been reported (88). The developments in membrane technology have been reviewed (89). Despite the research interest and potential, membranes have yet to be appHed at an industrial production scale (90). [Pg.70]

The purification of the galHum salt solutions is carried out by solvent extraction and/or by ion exchange. The most effective extractants are dialkyl-phosphates in sulfate medium and ethers, ketones (qv), alcohols, and trialkyl-phosphates in chloride medium. Electrorefining, ie, anodic dissolution and simultaneous cathodic deposition, is also used to purify metallic galHum. [Pg.160]

The production of CPO is based on relatively inexpensive cycHc substances these must be derivatized, however, to meet the requirements of resistance to heat softening and suitabiUty for metallization. Metathesis polymerization is problem-prone, since relatively large amounts of catalyst (WCl, C2H AlCl2) must be removed by solvent extraction (216). In the process, the price of CPO, at small batches, is several times higher than that of BPA-PC. [Pg.161]

In addition, solvent extraction is appHed to the processing of other metals for the nuclear industry and to the reprocessing of spent fuels (see Nuclearreactors). It is commercially used for the cobalt—nickel separation prior to electrowinning in chloride electrolyte. Both extraction columns and mixer-settlers are in use. [Pg.172]

The PGM concentrate is attacked with aqua regia to dissolve gold, platinum, and palladium. The more insoluble metals, iridium, rhodium, mthenium, and osmium remain as a residue. Gold is recovered from the aqua regia solution either by reduction to the metallic form with ferrous salts or by solvent-extraction methods. The solution is then treated with ammonium chloride to produce a precipitate of ammonium hexachloroplatinate(IV),... [Pg.168]

The principle of solvent extraction in refining is as follows when a dilute aqueous metal solution is contacted with a suitable extractant, often an amine or oxime, dissolved in a water-immiscible organic solvent, the metal ion is complexed by the extractant and becomes preferentially soluble in the organic phase. The organic and aqueous phases are then separated. By adding another aqueous component, the metal ions can be stripped back into the aqueous phase and hence recovered. Upon the identification of suitable extractants, and using a multistage process, solvent extraction can be used to extract individual metals from a mixture. [Pg.168]

Solvent Extraction. The selective partitioning of metals by Hquid—Hquid solvent extraction is one of the most powerful methods of... [Pg.563]

Copper. Domestic mine production of copper metal in 1994 was over 1,800,000 t. Whereas U.S. copper production increased in the 1980s and 1990s, world supply declined in 1994. There are eight primary and five secondary smelters, nine electrolytic and six fire refiners, and fifteen solvent extraction—electro winning (SX—EW) plants. Almost 540,000 t/yr of old scrap copper and alloy are recycled in the United States accounting for - 24% of total U.S. consumption (11). New scrap accounted for 825,000 t of contained copper. Almost 80% of the new scrap was consumed by brass mills. The ratio of new-to-old scrap is about 60 40% representing 38% of U.S. supply. [Pg.565]


See other pages where Metal solvent extraction is mentioned: [Pg.216]    [Pg.256]    [Pg.369]    [Pg.767]    [Pg.1455]    [Pg.216]    [Pg.256]    [Pg.369]    [Pg.767]    [Pg.1455]    [Pg.11]    [Pg.14]    [Pg.271]    [Pg.331]    [Pg.348]    [Pg.413]    [Pg.185]    [Pg.195]    [Pg.60]    [Pg.252]    [Pg.155]    [Pg.381]    [Pg.381]    [Pg.478]    [Pg.497]    [Pg.75]    [Pg.158]    [Pg.174]    [Pg.23]    [Pg.25]    [Pg.328]    [Pg.169]    [Pg.176]    [Pg.176]    [Pg.564]    [Pg.565]   
See also in sourсe #XX -- [ Pg.495 ]




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Metals extraction

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