Solvent extraction calculations involving

A comprehensive study of the complex interfacial processes involved in the solvent extraction of cupric ion by oxime ligands represents one of the most detailed and successful studies carried out with the RDC [37,38]. Recently, the technique was also used to study the transfer of tetrabutylammonium cations [43] and the kinetics of partitioning of compounds between octanol and water [44]. In the latter study, Fisk and coworkers investigated the rates of partitioning of 23 compounds from octanol to an aqueous phase. The RDC arrangement used most frequently in this work is of the o/o/w type. So according to Eq. (15), and can be calculated from the gradient and intercept of... 

Many reactions encountered in extractive metallurgy involve dilute solutions of one or a number of impurities in the metal, and sometimes the slag phase. Dilute solutions of less than a few atomic per cent content of the impurity usually conform to Henry s law, according to which the activity coefficient of the solute can be taken as constant. However in the complex solutions which usually occur in these reactions, the interactions of the solutes with one another and with the solvent metal change the values of the solute activity coefficients. There are some approximate procedures to make the interaction coefficients in multicomponent liquids calculable using data drawn from binary data. The simplest form of this procedure is the use of the equation deduced by Darken (1950), as a solution of the ternary Gibbs-Duhem equation for a regular ternary solution, A-B-S, where A-B is the binary solvent... 

From plots of the distribution ratio against the variables of the system— [M], pH, [HA] , [B], etc.—an indication of the species involved in the solvent extraction process can be obtained from a comparison with the extraction curves presented in this chapter see Fig. 4.3. Sometimes this may not be sufficient, and some additional methods are required for identifying the species in solvent extraction. These and a summary of various methods for calculating equilibrium constants from the experimental data, using graphical as well as numerical techniques is discussed in the following sections. Calculation of equilibrium constants from solvent extraction is described in several monographs [60-64]. 

Mention must be made of the use of an internal standard to monitor a reaction by g.l.c. analysis, and also to calculate the g.l.c. yield. Here, a known weight of the standard, inert to the reaction conditions and conforming to the other criteria of selection noted above, is added initially to the reaction mixture. In the case where samples of the mixture can be removed and loaded directly on to the column, the subsequent analysis presents no problem and may be deduced from the discussion above. In the case of samples which require evaporation of solvent prior to chromatographic examination, it is only necessary to ensure that the standard, and indeed the components to be analysed, do not volatilise under the conditions of concentration. If the samples require more involved solvent extraction procedures, then further experimentation is required to establish that... 

Concentrations of chromium in natural waters are very low. Thus, preconcentration of chromium is usually necessary. Some of the techniques used for pre-concentration include co-precipitation, solvent extraction using a variety of reagents, ion-exchange and electrodeposition. Most procedures have involved the determination of Crm and total chromium Crvl was then calculated by difference. 

If an apphcation proves to be technically feasible, the choice of solvent-to-feed ratio is determined by identifying the most cost-effective ratio between the minimum and maximum limits. For most applications, the maximum solvent-to-feed ratio will be much larger than the ratio chosen for the commercial process however, the maximum ratio can be a real constraint when dealing with applications exhibiting high mutual solubility, especially for systems that involve high solute concentrations. Additional discussion is given by Seader and Henley [Chap. 8 in Separations Process Principles (Wiley, 1998)]. Solvent ratios are further constrained for a fractional extraction scheme, as discussed in Fractional Extraction Calculations. ... 

The calculated uncertainties in A(.G° /RT will increase with the uncertainty in the interaction parameters and with increasing ionic strength. We have used the studies of [1963ALL/MCD] and the solubility investigations of many sulphate solids (see Section IX.1.3.3) to explore this effect, because the chemical system is simple, with Th(S04)3 as the dominant species. The solvent extraction data of [1963ALL/MCD], where the ionic strength varies from a very low value up to 4.5 m, were used as a first test of the impact of uncertainties in interaction parameters on the fitted values of AfG° /RT (Th(S04)3 ), as it is expected that this system will provide maximum variability in the calculated values. The values of all of the ion-interaction parameters involved in this system ate Usted in Table D-1 and the AjG° /RT values of all of the species considered in interpretation ate hsted in Table D-2. The fitted AfG° /RT (Th(S04)3 ) value was found to be -(1209.511 +0.086) when maximum values of all the ion interaction parameters, based on the uncertainties reported in Table D-1, were used and -(1209.348 + 0.088) when the minimum values were used. These compare with the value of A G° /RT (Th(S04)3 ) = -(1209.432 + 0.086) found when the mean values of the ion interaction parameters were used (see Section IX. 1.3.2). 

The heterogeneities of most concern to us are those that involve the presence of more than one phase. The analysis of multiphase systems can be important to the design and operation of many industrial processes, especially those in which multiple phases influence chemical reactions, heat transfer, or mixing. For example, phase-equilibrium calculations form the bases for many separation processes, including stagewise operations, such as distillation, solvent extraction, crystallization, and supercritical extraction, and rate-limited operations, such as membrane separations. 

Solvent Extraction and Liquid Membranes offers a comprehensive review of the most important principles, calculations, and procedures involved in this widely applicable separation technique. The book s pedagogical approach will benefit students and researchers in the field as well as working scientists and engineers who wish to apply solvent extraction to their own applications. 

Alonso et al, 2007) [CsMIMHBFJ Mass ratio ILimodel gasoline (MD) (1 1). MD 28 wt% of n-hexane, 28 wt cyclohexane, 28 wt% i-octane, 10 wt% toluene, 3 wt% thiophene and 3 wt% DBT, Stirling 2 h at 298 K, 4 h settle down and analyzed byGC. Thiophene distribution ratio (P), and solvent selectivity (S) were determined to calculated solvent extraction capacity for ternary systems involved in desulfurization. 

Heavy residual fuel oils and asphalts are not amenable to gas chromatography and give similar infrared spectra. However, a differentiation can be made by comparing certain absorption intensities [52], Samples were extracted with chloroform, filtered, dried, and the solvent evaporated off at 100 °C for a few minutes using an infrared lamp. A rock salt smear was prepared from the residue in a little chloroform, and the final traces of solvent removed using the infrared lamp. The method, which in effect compares the paraffinic and aromatic nature of the sample, involves calculation of the following absorption intensity ratios ... 

Leaching can be analyzed with respect to both the catalyst (rest state) and catalyst degradation products. The above reactions involve the separation of an n-octane product solution from a 5a catalyst residue at - 30 °C, and a subsequent n-octane extraction at - 30 °C. The data in Fig. 2, together with the solvent quantities employed, predict catalyst leaching of < 0.33% per cycle (calculated from the solubility at - 20 °C). This rises to 1.0 and 3.6% if phase separations are conducted at 0 and 20 °C, respectively. 

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