Manganese solvent extraction

Other methods reported for the determination of beryllium include UV-visible spectrophotometry [80,81,83], gas chromatography (GC) [82], flame atomic absorption spectrometry (AAS) [84-88] and graphite furnace (GF) AAS [89-96]. The ligand acetylacetone (acac) reacts with beryllium to form a beryllium-acac complex, and has been extensively used as an extracting reagent of beryllium. Indeed, the solvent extraction of beryllium as the acety-lacetonate complex in the presence of EDTA has been used as a pretreatment method prior to atomic absorption spectrometry [85-87]. Less than 1 p,g of beryllium can be separated from milligram levels of iron, aluminium, chromium, zinc, copper, manganese, silver, selenium, and uranium by this method. See also Sect. 5.74.9. 

Kingston et al. [32] preconcentrated the eight transition elements cadmium, cobalt, copper, iron, manganese, nickel, lead, and zinc from estuarine and seawater using solvent extraction/chelation and determined them at sub ng/1 levels by GFA-AS. 

Flynn [72] has described a solvent extraction procedure for the determination of 54manganese in seawater in which the sample with bismuth, cerium, and chromium carriers, is extracted with a heptane solution of bis(2-ethylhexyl) phosphate and the manganese back-extracted with 1M hydrochloric acid. After... 

A number of solvent extraction experiments have demonstrated that individual crown ethers in combination with a lipophilic sulfonic acid (such as didodecylnaphthalene sulfonic acid) are efficient, synergistic phase transfer agents for manganese(II) from aqueous solution into an organic phase." The X-ray structure of the manganese di-t-butylnaphthalenesul-fonate with cyclohexano-15-crown-5 ether as its toluene solvate has been reported." ... 

Pa-233 is extracted into diisopropyl ketone. The solvent extract containing Pa-233 is washed with 6M HCl for the removal of trace manganese salts and impurities. From the diisopropyl ketone extract, protactinium-233 is reextracted into an HCl-HF mixture solution containing 6M HCl and 0. IM HF. 

In the Amoco process, p-xylene is oxidized at 200 °C under 15-20 atm in acetic acid and in the presence of a catalyst consisting of a mixture of cobalt acetate (5% weight of the solution), manganese acetate (1%) and ammonium bromide. Owing to the highly corrosive nature of the reaction mixture, special titanium reactor vessels are required. One of the main difficulties of this process is to remove the intermediate oxidation products such as p-toluic acid or p-carboxybenzal-dehyde which contaminate TPA obtained by precipitation from the reaction medium. A series of recrystallization and solvent extraction apparatus is required to obtain fiber grade TPA with 99.95% purity. The overall yield in TPA is ca. 90% for a 95% conversion of p-xylene. 

In natural water samples, concentrations of manganese may often be at or below the detection limit of flame AAS, and solvent extraction or some other technique must be used for pre-concentration.29-32... 

Samples were purified before activation using the solvent extraction procedure of Hahn et al. (22) with thenoyltrifluoroacetone as the ligand. An activation routine was developed to avoid subsequent contamination with aluminum, to allow the excape of Ar, to monitor flux variations, and to facilitate spectrum stripping of residues of manganese, aluminum, and sodltun (15). The advent of high efficiency germanium detectors has significantly reduced the... 

FIGURE 8.1-1 Solvent extraction portion of the Kannecott copper-nickel carbonate procase for desp-rea manganese nodules. Adapted from U.S. Patent 3,907,966 in Ref. 11. 

Determination of manganese in urine can be made by flame AAS after extraction into an organic solvent (Van Ormer and Purdy 1973) and after ion-exchange separation (Pan-tucek, 1981). Solvent extraction procedures have also been described for GF-AAS (Buchet et al.. 1976 Watanabe et al., 1978). As the direct determination of manganese in... 

If solvent extraction is carried out in the presence of cyanide, the zinc group of metals (Zn, Cd, Hg) is complexed and they will not extract. Addition of citrate complexes the elements of the ammonia group (Fe, Al, etc.) so that their hydroxides will not precipitate. The precipitation of the alkaline earth phosphates can be prevented by the addition of hexametaphosphate (Jl). Under these conditions, Bi(III), TI(I), and Sn(II) interfere in alkaline solution. The bismuth can be removed by preextraction at pH 3. Alternatively, if a positive lead test is found, bismuth could be ruled out or confirmed by back-extracting at pH 3. If bismuth is present, it will remain in the organic layer while lead will go into the aqueous phase. Extraction of thallium can be prevented by extracting the lead at pH 6.0-6.4 with chloroform. Or the thallium can be back-extracted at this pH this requires much closer control of the pH. The oxidation of dithizone by air is catalyzed by the presence of significant amounts of manganese (II). 

Chemical treatment of a sample also may be used to control interferences. A number of techniques are available, including separation by precipitation, solvent-solvent extraction, and ion exchange techniques. For example, 8-hydroxyquinoline can be used to precipitate and separate a number of elements, such as manganese, copper, cobalt, nickel, and iron, from other major matrix elements. The test solution therefore has fewer extraneous elements present and fewer possibilities of interference exist. 

FIGURE 8.1 2 Deepsea Ventures solvent extraction flowsheet for separation of metals in a manganese nodule leach liquor. From Ref. 11, with permission. 

The copper solvent extraction raffinate is split with a portion of the raffinate returning to leaching and the balance advancing to cobalt, zinc and manganese recovery. The raffinate for cobalt, zinc and manganese recovery is first neutralized to remove iron and aluminum from solution and then subjected to a novel direct solvent extraction process (DSX) developed by CSIRO (Australia) [4-6]. The direct solvent extraction process uses a mixture of Versatic 10... 

C. Y. Cheng and M. D. Urbani. Solvent extraction process for separation cobalt and/or manganese from impurities in leach solutions . Patent Publication No. WO 2005/073415 Al. 

Removal of manganese from solution by solvent extraction... 

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