Nitric acid extraction

Step 3 The residue from step two is treated twice with 8.8 M H202 and evaporated to near dryness. To this is added 50 mL of ammonium acetate adjusted to pH 2 using nitric acid. Extraction is repeated as in step 1. 

Sastre J, Sahuquillo A, Vidal M, Rauret G. Determination of Cd, Cu, Pb and Zn in environmental samples microwave-assisted total digestion versus aqua regia and nitric acid extraction. Anal. Chim. Acta 2002 462 59-72. 

The stoichiometric compositions may he determined from cobalt analysis of nitric acid extract of the solid material by AA, ICP, or other instruments. The structural form of sulfides and their composition may be analysed by x-ray diffraction or fluorescence methods. 

Elemental composition Co 73.42%, O 26.58%. The nitric acid extract of the oxide may be analyzed for cobalt by various instrumental methods (see Cobalt). Additionally, the solid crystalline product may be characterized by x-ray techniques. 

Copper is determined by AA or ICP spectrophotometry of copper(II) hydroxide nitric acid extract. Heating the solid hydroxide dehydrates to CuO. The moles of water loss may be measured by gravimetric analysis. The black CuO residue may be identified by x-ray analysis and physical tests. 

Elemental composition Cu 33.36%, I 66.64%. Either compound or mineral copper(I) iodide is identified by x-ray diffraction or fluorescence method. Copper may be analyzed in nitric acid extract of copper(I) iodide by various instrumental techniques (see Copper). 

Iron carbonyls may be identified by electron diffraction and x-ray analysis. Also, its solutions in appropriate organic solvents, such as ether, methanol, or acetone may be analyzed by GC/MS. The characteristic mass spectra should indicate the molecular ions corresponding to the carbonyl as well as the mass spectra of CO and Fe(CO)n, where n is the number of CO units in the fragmented mass ions. Flame- or furnace-AA or ICP/AES analysis may be apphed on the nitric acid extract of the compound(s) after appropriate dilution to determine the concentration of iron (See Iron). 

Elemental composition Pb 68.32%, S 10.57%, O 21.10%. the solid crystalline powder or the mineral anglesite may be characterized by x-ray techniques and physical properties. Lead can be analyzed in the sohd compound or its nitric acid extract by various instrumental techniques (See Lead). 

Elemental composition Li 31.85%, B 49.66%, H 18.50%. The compound is dissolved in water cautiously and the evolved hydrogen is measured by GC using a TCD. The aqueous solution is treated with nitric acid and the diluted nitric acid extract is analyzed for lithium by atomic absorption or emission spectroscopy (See Lithium). 

Elemental composition Li 46.45%, 0 53.55%. The oxide may he identified from its physical properties and characterized by x-ray analysis. Lithium composition in the oxide may be determined by analyzing the nitric acid extract by AA or ICP (See Lithium). 

Elemental composition Ni 22.85%, C 46.75%, H 5.49%, O 24.91%. The compound may be characterized by its physical properties, elemental analysis, and by IR, UV and NMR spectra and x-ray diffraction data. A benzene or chloroform solution may be injected directly into a GC column and may be identified from its mass spectra. The characteristic mass ions for its identification by GC/MS are 58, 60, 100, 257. The aqueous solution or the nitric acid extract may be analyzed either by flame or furnace AA, or by ICP-AES to determine nickel content. 

Elemental composition Ni 64.68%, S 35.33%. The compound may be identified by x-ray crystallographic and physical properties. Nickel may be measured in nitric acid extract by AA or ICP methods (See Nickel). 

Elemental composition Sr 47.70%, S 17.46%, O 34.84%. Strontium sulfate can be characterized by x-ray crystallography. A nitric acid extract is analyzed for strontium. An aqueous solution (the salt is only slightly soluble) is filtered or decanted from insoluble material and measured by ion chromatography. 

Erlinger, C., Gazeau, D., Zemb, Th. et al. 1998. Effect of nitric acid extraction on phase behavior, microstructure and interactions between primary aggregates in the system dimethyldibutyl-tetradecylmalonamide (DMDBTDMA)/ -dodecane/water A phase analysis and small-angle X-ray scattering (S AXS) characterization study. Solvent Extr. Ion Exch. 16 707-738. 

Lefrancois, L., Belnet, F., Noel, D., Tondre, C. 1999. An attempt to theoretically predict third-phase formation in the dimethyldibutyltetradecylmalonamide (DMDBTDMA)/ dodecane/water/nitric acid extraction system. Sep. Sci. Technol. 34 (5) 755-770. 

The metal ion extraction should increase with the increase in extractant concentration as well as with nitrate ion concentration. With the increasing concentration of nitric acid, beyond a point however, a decrease in metal ion extraction is observed, which is ascribed primarily to the (i) formation of anionic actinide complexes, and (ii) decrease of extractant concentration caused by nitric acid extractant complex formation. The latter is represented as ... 

Several spectroscopic techniques, namely, Ultraviolet-Visible Spectroscopy (UV-Vis), Infrared (IR), Nuclear Magnetic Resonance (NMR), etc., have been used for understanding the mechanism of solvent-extraction processes and identification of extracted species. Berthon et al. reviewed the use of NMR techniques in solvent-extraction studies for monoamides, malonamides, picolinamides, and TBP (116, 117). NMR spectroscopy was used as a tool to identify the structural parameters that control selectivity and efficiency of extraction of metal ions. 13C NMR relaxation-time data were used to determine the distances between the carbon atoms of the monoamide ligands and the actinides centers. The II, 2H, and 13C NMR spectra analysis of the solvent organic phases indicated malonamide dimer formation at low concentrations. However, at higher ligand concentrations, micelle formation was observed. NMR studies were also used to understand nitric acid extraction mechanisms. Before obtaining conformational information from 13C relaxation times, the stoichiometries of the... 

In the reverse TALSPEAK process, the An(III) + Ln(III) fraction is first coextracted from a feed, the acidity of which has to be reduced to 0.1 M by denitration or nitric acid extraction. An(III) are then selectively stripped using DTPA in citric acid (1 M) at pH 3 (hence the name reverse TALSPEAK process), and the Ln(III) are finally stripped by 6 M HN03. Attempts to apply this TALSPEAK variant to the treatment of actual UREX + raffinates are reported in the literature, but they involve several steps. The problematic Zr and Mo elements are first removed by direct extraction with HDEHP (0.8 M in di-iso-propylbenzene) from the high-acidity raffinate stream arising from the UREX + co-decontamination process (238). The remaining fission products and actinides can then be concentrated by acid evaporation and denitration processes. This concentrate is further diluted to a lower acidity (e.g., [HN03] = 0.03 M) to allow the coextraction of An(III) and Ln(III) by the TALSPEAK solvent. 

Dual-host approaches have also been used to good effect for CsN03 extraction. Nitrate is a common anion found upon nitric acid extraction of 137Cs+ in the nuclear industry. Cs+ is conveniently com plexed by a large crown ether such as tetrabenzo[24] crown-8 while simple tripodal amide hosts of type 5.31 (where R is a long alkyl group to impart lipophilicity) are effective at binding N03 . Extraction efficiency of Cs+ from water into 1,2-dichloroethane was found to be enhanced by a factor of up to 4.4 in the presence of the anion host.28... 

Analysis. The heating value, ash content, and sulfur distribution of the raw and treated coals were determined according to ASTM procedures (7). Iron in the extracts of the raw and treated coals was determined by titration with a cerium (IV) solution. Iron in the residues from the acid extractions of the raw and treated coals was determined spectrophotometrically using ferrozine (20). The liquid extracts were analyzed for total sulfur (as sulfate) by ion chromatography after separation of the sulfate from nitrate on an alumina column (21). Nitrogen was determined in the raw and treated coal and in their nitric acid-extracted residues by a modified Kjeldahl method. 

Selenium. Selenium has been determined colorimetrically by formatrion of a diaminobenzidine complex, 420 nm, after an oxidation and distillation (13). Method S-190 for selenium in air extracts the analyte from filters by 0.1 N nitric acid leaching. The nitric acid extracts are aspirated into an argon/hydrogen-air flame, and the absorbance is recorded for the 196 nm analytical line. The method discourages the use of a carbonaceous flame like air-acetyelene. Many analysts use air acetylene because it is convenient. Background correction is required for either flame type. 

S. Y. LamLeung, V. K. M. Cheng, Y. W. Lam, Application of a microwave oven for drying and nitric acid extraction of mercury and selenium from fish tissue, Analyst, 116 (1991), 957-959. 

When more them one solute is involved in the consideration of the process design, the situation becomes much more complex since the extraction behaviours of the different solutes will usually be interdependent. In the case of irradiated thermal reactor fuels the solvent extraction process will be dealing with uranium containing up to ca. 4% of fission products and other actinides. These will have only a minor effect on uranium distribution so that a single-solute model may be adequate for process design. However, in some cases nitric acid extraction may compete with U02 extraction and a two-solute model may be needed. In the case of breeder reactor fuels the uranium may contain perhaps 20% of plutonium or thorium. Neptunium or protactinium levels in such fuels may also not be negligible and, under these circumstances, the single-solute... 

Sediment. About 50 g of dried sediment was used in transuranic element analyses. Two teachings of the sediment with 200 ml hot 8M nitric acid extracted the plutonium completely and, doubtless, other transuranic elements. Some workers prefer to fuse sediments completely (7, 8), but this is not necessary when the source of transuranic elements is global fallout or nuclear power plant waste. Fusion is probably essential when the transuranic elements in a sample are in relatively resistant... 

Aravantinos-Zafiris, G. and Qreopoulou, V. 1992. The effect of nitric acid extraction variables of orange pectin, J. Sci. Food Agric., 60 127-129. 

For the ion chromatographic analysis of chloride in cement, that cancels out the passivation of steel surfaces in concrete and, thus, is only admitted up to a maximum content of 0.1%, Maurer et al. [93] developed a procedure in which the cement sample is extracted with nitric acid. Since a direct chloride determination is impossible due to the high nitrate concentration in the extract, silver nitrate is added in three-fold excess to the nitric acid extract. The precipitated silver chloride is filtered off and subsequently dissolved in 100 mL of a 0.25% ammonium hydroxide solution. This solution, according to the chloride concentration, can be further diluted with de-ionized water or injected directly. 

Plutonium purification proceeds by reducing the aqueous phase pH that oxidizes the plutonium to Pu" +, which then extracts into the TBP phase. Impurities stay in the aqueous phase. The TBP phase strip-ping/extraction cycle is repeated to complete the plutonium purification. The uranium is purified using the same TBP/nitric acid extraction/stripping cycle. Careful control of the each element s oxidation state in the extraction cascade produces the plant-scale separations of uranium from plutonium of 10 . Fission product decontamination factor was 10. The plutonium and uranium recovery is about 99.9% with 95% of the nitric acid values and 99.7 /o of the organic solvent recycled. ... 

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