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Extractive stripping

The component C in the separated extract from the stage contact shown in Eigure 1 may be separated from the solvent B by distillation (qv), evaporation (qv), or other means, allowing solvent B to be reused for further extraction. Alternatively, the extract can be subjected to back-extraction (stripping) with solvent A under different conditions, eg, a different temperature again, the stripped solvent B can be reused for further extraction. Solvent recovery (qv) is an important factor in the economics of industrial extraction processes. [Pg.60]

Uranium Purification. Subsequent uranium cycles provide additional separation from residual plutonium and fission products, particularly zirconium— niobium and mthenium (30). This is accompHshed by repeating the extraction/stripping cycle. Decontamination factors greater than 10 at losses of less than 0.1 wt % are routinely attainable. However, mthenium can exist in several valence states simultaneously and can form several nitrosyl—nitrate complexes, some for which are extracted readily by TBP. Under certain conditions, the nitrates of zirconium and niobium form soluble compounds or hydrous coUoids that compHcate the Hquid—Hquid extraction. SiUca-gel adsorption or one of the similar Hquid—soHd techniques may also be used to further purify the product streams. [Pg.206]

After the second extraction/stripping cycle, the plutonium is concentrated by evaporation or by preferential adsorption (qv) on ion-exchange resins. As in the case for uranium, the newer faciHties, such as THORP, use only a single purification step. [Pg.206]

In a large number of processes, there ate unit operations related to vapot-Hquid separations distillation, absorption, extraction, stripping, flashing, and separation of Hquid and vapor stream arising from changes in temperatures and pressures. Calculations for these unit operations necessitate trial and... [Pg.73]

Extractive Stripping of Inert-Rich Hydrocarbon Gases with a Preferential Physical Solvent. U.S. Patent 4,680.042, Jul. 14, 1987. [Pg.331]

Which separation operations should be used for interception (e.g., adsorption, extraction, stripping) ... [Pg.9]

Dynamic headspace-extraction stripping and purge-and-trap methodology are used most often for determination of M-hcxanc in water and hazardous wastes. Dynamic headspace extraction techniques have been applied to water samples (Roberts and Burton 1994) and sediment (Bianchi et al. 1991). Detection limits of 0.5 g/L were reported for lake water (Roberts and Burton 1994) and 20 ng/kg (ppt) for sediment (Bianchi et al. 1991). Supercritical fluid extraction (SFE) is a relatively new technique that has been applied to -hcxane in soil (Yang et al. 1995). Membrane extraction of M-hexane from water samples has been developed to provide online, continuous monitoring (Wong et al. 1995 Xu and Mitra... [Pg.214]

Element Extraction Stripping Element Extraction Stripping... [Pg.538]

Selection of a suitable reverse micellar system is mainly based on the nature and charge of the protein to be extracted. The optimization of forward and back extraction processes is carried out by studying the effect of various parameters (Sect. 3) on the extraction/stripping of proteins experimentally using full or... [Pg.157]

The back-extraction (stripping) of palladium is achieved in the hydroxyoxime process by contacting the loaded organic phase with a concentrated solution of hydrochloric acid (about 6 M), thus causing the reversal of reaction (76). Palladium can be recovered from the strip liquor by the addition of ammonia, and the precipitated Pd(NH3)2Cl2 can be calcined to yield pure palladium metal. In the dialkyl sulfide process, however, the extraction reaction (75) is independent of acidity, and is therefore reversed by the use of aqueous ammonia, which forms a stable cationic complex with palladium(II) ... [Pg.807]

SYNTHESIS Into 1 L H20 that was being stirred magnetically, there was added, in sequence, 62 g toluhydroquinone, 160 mL 25% NaOH, and 126 g dimethyl sulfate. After about 2 h, the reaction mixture was no longer basic, and another 40 mL of the 25% NaOH was added. Even with stirring for a few additional days, the reaction mixture remained basic. It was quenched in 2.5 LHzO, extracted with 3x100 mL CHjClj and the pooled extracts stripped of solvent under vacuum. The remaining 56.4 g of amber oil was distilled at about 70 °C at 0.5 mm/Hg to yield 49.0 g of 2,5-dimethoxytoluene as a white liquid. The aqueous residues, on acidification,... [Pg.266]

SYNTHESIS To a solution of 166 g bourbonal in I L MeOH there was added a solution of 66 g KOH pellets in 300 mL H,0. There was then added 120 g ethyl bromide, and the mixture was held at reflux on the steam bath for 3 h. The reaction was quenched with three volumes of H20, and made strongly basic by the addition of 25% NaOH. This was extracted with 3x300 mL CH.C1, and the pooled extracts stripped of solvent under vacuum. There remained 155 g of 3,4-diethoxybenz-aldehyde as a fluid oil that had an infra-red spectrum identical (except for being slightly wet) to that of a commercial sample from the Eastman Kodak Company. [Pg.390]

A solution of 5.6 g of borane-methyl sulfide complex (10 M BH3 in methyl sulfide) in 45 mL THF was placed in a He atmosphere, cooled to 0 °C, treated with 11.6 g of 2-methylbutene, and stirred for 1 h while returning to room temperature. To this there was added the crude 3,4-diethoxy-5-ethylthiostyrene in 25 mL THF and the stirring was continued for 1 h. The excess borane was destroyed with about 2 mL MeOH. There was then added 11.4 g elemental iodine followed by a solution of 2.2 g NaOH in 40 mL hot MeOH. This was followed by sufficient 25% NaOH to minimize the residual iodine color (about 4 mL was required). The reaction mixture was added to 500 mL H,0 containing 4 g sodium hydrosulfite. This was extracted with 3x75 mL petroleum ether, and the pooled extracts stripped of solvent under vacuum to yield 24.5 g of crude l-(3,4-diethoxy-5-cthylthiophenyl)-2-iodoethane as a viscous yellow oil. [Pg.468]

With many other combinations, the composition of the species extracted are mostly uncertain and the equilibria involved are often very complex involving polymeric species, many times. However many of these systems hold promise of offering useful separation schemes since in some of these systems using carboxylic acids, for example, the extraction and back extraction (stripping) of the metal ions can be achieved in the same system simply by controlling the pH of the aqueous medium. [Pg.82]

L-L extraction, stripping, Temperature Recycle of MSA increases the costs... [Pg.73]

A separation is diluted when the distillate or the bottom product is less than 5 wt% with respect to the feed. The distillation (simple, extractive or azeotropic) might not be the most economical, but other methods, such as liquid-liquid extraction, stripping, crystallization, adsorption, or membrane permeation, should be tried. The decision depends on the mixture composition and the nature of the components. [Pg.73]

Chemical engineers have been solving distillation problems by using the equilibrium-stage model since 1893 when Sorel outlined the concept to describe the distillation of alcohol. Since that time, it has been used to model a wide variety of distillation-like processes, including simple distillation (single-feed, two-product columns), complex distillation (multiple-feed, multiple-product columns), extractive and azeotropic distillation, petroleum distillation, absorption, liquid-liquid extraction, stripping, and supercritical extraction. [Pg.30]

The Thiele-Geddes method can be used for the solution of complex distillation problems, and for other multi-component separation processes. A series of programs for the solution of problems in distillation, extraction, stripping and absorption, which use an iterative procedure similar to the Thiele-Geddes method, are given by Hanson et al. (1962). [Pg.545]

The transport of titanium(IV) species through HLM can be formally described as a simultaneous combination of diffusion, extraction, and stripping operations occurring in nonequilibrium conditions. These systems are very complicated to analyze and therefore, some assumptions are needed for simplification. Extraction kinetics and stripping processes are much faster for most metal ions than their diffusion, and many researchers have adopted the local extraction equilibrium of feed-extractant and extractant-strip phases at the membrane interfaces. So, the chemistry of the OHLM system at equilibrium conditions has to be analyzed. [Pg.378]

Cichy W, Schlosser S, and Szymanowski J. Recovery of phenol with CYANEX 923 in membrane extraction-stripping systems. Solv Extr Ion Exch, 2001 19(5) 905-923. [Pg.404]

Wang, J. Freiha, B.A. Deshmukh, B.K. Adsorptive extractive stripping voltammetry of phenothiazine compounds at carbon paste electrodes. Bioelectrochem. Bioenerg. 1985, 14, 457-467. [Pg.1501]


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See also in sourсe #XX -- [ Pg.319 ]




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