摘要:

A review is given of recent work on the measurement of droplet coalescence and breakage rates in a packed and a pulsed plate extraction column using a newly developed colorimetric technique. The results, which were interpreted in terms of second order coalescence and first order breakage rate constants, showed that the droplet interaction rates are considerably lower in the pulsed column. The rate constants can also be used to predict accurately the steady state droplet size distribution, and to study theoretically the effect of droplet coalescence and breakage on mass transfer rate. Deficiencies in the available mass transfer coefficient data for droplets, both individual and in “swarms”, are pointed out.

ISSN:0736-6299    

DOI:10.1080/07366298408918462

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Models for simulating the performance of extraction columns have been extended to include partially miscible solvents. Simultaneously, a comprehensive experimental study was carried out in which the concentration profiles of all components and all relevant hydrodynamic parameters in a pilot plant were measured, using liquid systems recommended by the European Federation of Chemical Engineers. True mass transfer coefficients were determined from the experimental data using a computer-aided curve-fitting technique to allow for the influence of backmixing. The coefficients obtained in this way were similar to those calculated for single drops.

ISSN:0736-6299    

DOI:10.1080/07366298408918463

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A new carboxylic acid extractant containing a sulfur atom, α-butylthiolauric acid(abbreviated as α-BTLA) was synthesized to investigate the extraction equilibrium of silver(I) from 1 mol/dm3aqueous ammonium nitrate solution with its toluene solution at 30°C. Moreover, the extraction of silver(I) with palmitic acid in toluene was studied to compare with the extraction properties of α-BTLA. It was found that silver(I) is extracted as AgR×3HR for both carboxylic acids(HR) according to the following equation.

ISSN:0736-6299    

DOI:10.1080/07366298408918464

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Mixtures of a linear polyether, l,13-bis[8-quinolyl]-l,4,7,10,13-pentaoxatridecane, K-5, and thenoyltrifluoroacetone, HTTA, have been shown to exhibit synergistic character in the extraction of trivalent lanthanides and actinides. The effect of the addition of K-5 to the organic phase on the extractions of Ce(III), Eu(III), Tm(III), Am(III), Cm(III), Bk(III), and Cf(III) by HTTA in chloroform from 0.5MNaNO3at 25°C has been measured. These results indicate the extraction is enhanced by the formation of M(TTA)3K-5 adduct in the organic phase. The organic phase stability constants for the formation of these synergistic species have been calculated for all the metals studied. The magnitude of these organic phase stability constants for K-5 are similar to other common neutral donors. The order of stability does not follow the normal trend based on charge-to-radius ratio, but follows a pattern based on size, with Am(III) being the most stable.

ISSN:0736-6299    

DOI:10.1080/07366298408918465

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Data on the distribution of uranium(IV,VI), plutonium(III) and nitric acid between 30 vol.% TBP in dodecane and aqueous nitrate solutions also containing hydrazine nitrate were mathematically described by empirical equations. This made it possible to present distribution ratios of the extracted components as functions of concentrations and temperature at a single variable being varied and other variables being kept constant. Salting-out and self-salting-out action of the electrolytes present in the system as well as mutual replacement of the extracted components from the organic phase are shown.

ISSN:0736-6299    

DOI:10.1080/07366298408918466

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Own and published data were evaluated for characterizing the effect of temperature on the distribution of nitric acid and plutonium(IV). The solutes were distributed between 30 vol.% TBP in an aliphatic diluent and aqueous solutions containing nitric acid and zero to macro amounts of plutonium(IV) and uranyl nitrates. The temperature dependence of the distribution ratios is described with empirical model equations and examples of the dependence in the absence and presence of uranium(VI) are given. Taking infinite dilution of all solutes of the system as a standard state, the enthalpy change of the extraction reaction could be estimated as −17 kJ/mol for nitric acid but no numerical estimate was possible for plutonium(IV).

ISSN:0736-6299    

DOI:10.1080/07366298408918467

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Distribution data for the systems Th(NO3)4:HNO3/30 % TBP in dodecane and Th(NO3)4:UO2(NO3)2:HNO3/30 % TBP in dodecane have been evaluated experimentally. By means of these data a caleulationa1 model has been derived which makes it possible to determine data in the investigated range. A method is also described for the evaluation of distribution data at very low thorium concentrations.

ISSN:0736-6299    

DOI:10.1080/07366298408918468

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Defluorination of WPA to feed grade levels (P:F > 100) was found to be effective with acids of low Al content. Acids with higher Al levels cannot be defluorinated effectively due to a sharp decrease in the distribution coefficient of the fluorine. This is attributable to complexation of fluorine by Al. An important part of manufactured phosphoric acids contain aluminum in levels that render defluorination to feed grade requirements impractical. Treating such acids with SiO2as well as preconcentration prior to extraction result in some improvement in extractability but provides for marginal improvements only.

ISSN:0736-6299    

DOI:10.1080/07366298408918469

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A solvent extraction process is described for defluorination and desulfation of filter phosphoric acids with high Al content. The solvent used contain an amine and phosphoric acid as main constituents. The acid obtained is compatible with feed-grade requirements. It can be concentrated to 56–60% P2O5by multiple effect evaporation, decreasing steam requirements by 50%. If an acid-base couple solvent is used in this process, part of the extracted phosphate can be recovered by back-wash with water in the form of highly purified phosphoric acid low in metals, fluorine and sulfate. The remainder of the acid along with the extracted sulfate is obtained as ammonium salt. The extracted F is converted into crystaline alkali fluorosilicate.

ISSN:0736-6299    

DOI:10.1080/07366298408918470

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A review of solvent extraction separation studies of niobium and tantalum, either individually or together from other associated elements, using various solvents, is presented.

ISSN:0736-6299    

DOI:10.1080/07366298408918471

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor