Showing papers in "Solvent Extraction and Ion Exchange in 1985"

THE TRUEX PROCESS - A PROCESS FOR THE EXTRACTION OF THE TKANSURANIC ELEMENTS EROM NITRIC AC In WASTES UTILIZING MODIFIED PUREX SOLVENT*

Abstract: A generic transurantc (TRU) element extraction/recovery process was developed based on the use of octyl(phenyl)-N,N-diiso-butylcarbamoylmetliylphosphine oxide, 0φD(iB)CMPO, dissolved in PUREX process solvent (tribntyl phosphate, TBP, in normal paraffluic hydrocarbon, NPH). The process (called TRUEX) is capable of reducing the TRU concentration by many orders of magnitude In waste solutions containing a wide range of nitric acid, salt, and fission product concentrations. A major feature of the process is that it is readily adaptable for waste processing in existing fuel reprocessing facilities.

SELECTIVITY-STRUCTURE TRENDS IN THE EXTRACTION OF Co(II) AND Ni(II) BY DIALKYL PHOSPHORIC, ALKYL ALKYLPHOSPHONIC,AND DIALKYLPHOSPHINIC ACIDS∗

Abstract: The conditional equilibrium constants for the extraction reactions of Co(II) and Ni(ll) by toluene solutions of homologous series dialkyl phosphoric, alkyl alkylphosphonlc, and dialkyl-phosphlnic acids have been evaluated. From the equilibrium constants the Co/Ni selectivity factors were calculated. Absorption spectra and water extraction data for organic solutions of selected reagents which had extracted the metals were also obtained. The data have allowed us to establish correlations between the structure of the extractants and their selectivity for Co(II) over Ni(II). The two main features controlling the different extractive behavior of Co(II) and Nl(II) with the organo-phosphorus reagents appear to be the different degree of hydration of the extracted complexes and their different coordination geometry. Sterlc hindrance effects, introduced by branchings on the alkyl chains greatly reduce the extractability of Ni(II) which forms octahedral complexes in the organic phase, while the extraction ...

Separation of actinides and lanthanides from acidic nuclear wastes by supported liquid membranes

Abstract: Supported liquid membranes, SLM, consisting of a solution of 0.25 M octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and 0.75 μ tributylphosphate (TBP) in decalin absorbed on thin micropocous polypropylene supports, have been studied for their ability to perform selective separations and concentrations of actinide and lanthanide ions from synthetic acidic nuclear wastes. The permeability coefficients of selected actinides (Am, Pu, U, Np) and of some of the other major components of the wastes have been measured using SLMs in flat-sheet and hollow- fiber configurations. The results have shown that with the thin (25 μm) flat-sheet SLMs, using Celgard® 2500 as support, the membrane permeation process is mainly controlled by the rate of diffusion through the aqueous boundary layers. With the thicker (430 μmpar; hollow-fiber SLMs, using Accurel® hollow-fibers as support, the membrane permeation process Is controlled by the rate of diffusion through both the SLM and the aqueous boundar...

Extraction of some lanthanides and actinides by 15-crown-5 thenoyltrifluoroacetone mixture in chloroform

Abstract: The extraction of Eu3+, Tm3+, and Yb3+ by a mixture of thenoyltrifluoroacetone (HTTA) and 15-Crown-5 (15C5) in chloroform from a 0.1-ionic strength acetate buffer was investigated. Large enhancement in the extraction for these lanthanides was obtained when a mixture of the two extractants was used. Experimental data indicated that this enhancement is a result of the formation of a lanthanide adduct in the organic phase of the type Ln(TTA) 3° 2CE, where CE refers to a crown ether. The synergistic factors (S.F.), mixed extraction constants and formation constants of the different adducts in the organic phase were found to take the sequence Eu3+ > Tm3+ > Yb3+. Using 12-Crown-4 (12C4), no enhancement in the extraction was observed. This was explained in terms of the small cavity size of 12C4 relative to 15C5. The same system comprising HTTA-15C5 was also studied for the extraction of Pu4+, Am3+, Nd3+, and Er3+. Moderate enhancement was obtained for the extraction of Am3+ while no increase in the extraction wa...

Extractionoftervalentlanthanideswith acidic organophosphorus compounds

Abstract: The equilibrium.extraction behavior for a series of tervalent lanthanide ions (Ln3+) using a chloroform solution containing di(2-ethyl-hexyl) phosphoric acid (HDEHP), diphenylphosphinic acid (HDPP), dibutylphosphorothioic acid (HDBPT), di-n-octylphosphorodithoic acid (HDOPDT), or di(2-ethylhexyl)phosphorodithioic acid (HDEHPDT), either alone or combined with adduct forming agents is studied. The extracted species are Ln(DEHP) 3(HDEHP) 3, Ln(DPP)3 (HDPP)3, Ln(DBPT)3, and are Ln(DBPT)3(HDERP)3 in the presence of o-phen and its analogs (B). Extraction constants for the lanthanides follow the order HDPP > HDEHP > HDBPT » HDOPDT. HDPP was the most selective of all the extractants examined. HDOPDT and HDEHPDT were found to be ineffective lanthanide extractants.

The extraction of cesium and strontium from acidic high activity nuclear waste using a purex process compatible organic extractant

Abstract: Purex process compatible organic systems which selectively and reversibly extract cesium and strontium from synthetic mixed fission product solutions containing3M HNO3, have been developed. This advance makes the development of continuous solvent extraction processes for their recovery more likely. The matrix solution from the Purex process consists of tributyl phosphate (TBP) and kerosene. For cesium and strontium recovery a macrocyclic polyether (crown compound) has been developed for each element. When used in conjunction with a liquid cation exchanger in the matrix solution, the crown compounds will extract either alkali metals or alkaline earths from the synthetic mixed fission product solution. The organic cation exchangers used in this research were didodecylnaphthalene sulfonic acid (DNS) and dinonylnaphthalene sulfonic acid (NNS). As was expected both zirconium and ruthenium also tend to be extracted due to the TBP in the matrix solution and to their complex chemistry. The most favorable cesium a...

Synthetic inorganic ion-exchange materials xxxix. synthesis of titanium(iv) antimonates and their ion exchange properties for alkali and alkaline earth metal ions

Abstract: Titanium antimonate (TiSbA) cation exchanger, prepared under different molar ratios of titanium and antimony, has been characterized by X-ray diffraction, thermal analysis, infrared spectra, and pH-titration. The pH-titration curves showed apparently monobasic acid type. The uptakes of alkali metal ions increased with increasing pH of the solution and with decreasing the molar ratio (Ti/Sb) in the exchanger. An unusual selectivity sequence of the order Na < K < Rb < Cs was found for microamounts of alkali metal ions on TiSbA, while the regular selectivity sequence Mg < Sr < Ba was found for alkaline earth metal ions in nitric acid media. The maximum separation factors, ∝Li Na(=55) and ∝(=186) were found on the TiSbA with Ti/Sb molar ratio of 1.56, respectively. The effective separations of Li from Na and K, Mg from Ca and Sr have been achieved by using a relatively small column (2 cm × 0.5 cm i.d. ) containing TiSbA of Ti/Sb ratio 1.56.

Variations in the solvent extraction behavior of bifonctional phosphorus-based compounds modified with tbp

Abstract: The solvent extraction of americium from nitric acid by several modified bifunctional extractants in CCl/sub 4/ has been investigated. For all the compounds examined, addition of a modifier such as tributylphosphate (TBP) enhances distribution ratios at high aqueous acidities. The effect of the modifier at lower acidities varies depending on the basicity of the bifunctional extractant. While the most basic extractants show significantly reduced distribution ratios from lower acid solutions upon TBP addition, for the less basic compounds only slight reductions or, in some cases, even moderate increases in extraction are observed. Studies of the effect of modifier basicity on extraction behavior with modifiers fall within the range of variations observed for diluent effects with extractants of this type. Increases in high acid distribution ratios upon TBP addition to an extractant as simple as trioctylphophine oxide indicate that this modification of extraction behavior may be of general use for a wide range of neutral extractants. 21 references, 3 figures, 1 table.

The influence of crosslinkage on the distribution coefficients and anion exchange behaviour of some elements in hydrochloric acid

Abstract: Equilibrium distribution coefficients are presented for Cu(II), Zn(II), Cd(II), Fe(III), Ga(III), In(III), Th(IV) and U(VI) on the strongly basic anion exchangers AG1-X2, AG1-X4, AG1-X8, AG1-X10 and AG MP-1 in hydrochloric acid. Coefficients generally increase with increase in crosslinkage, while exchange kinetics show a marked improvement with decrease in crosslinkage. Elution curves for some elements on the lower crosslinked resins AG1-X2 and AG1-X4 and on the macroporous resin AG MP-1 demonstrate the advantages of these resins for some separations.

Determination of the equilibrium constants of organophosphorus liquid-liquid extractants by inductively coupled Plasma-Atomic Emission Spectroscopy

Abstract: The technique of inductively coupled Plasma-Atomic Emission Spectroscopy(ICP) has been used for determining the equilibrium constants of organophosphorus extractants in liquid-liquid extraction systems. The 213.618am first order atomic emission line of phosphorus was monitored to determine the equilibrium constants. The relevant equilibrium constants of bis(2,4,4-trimethylpentyl)phosphinic acid, bis(2- ethylhexyl)phosphoric acid, diphenylphosphinic acid, trioctylphosphine oxide and tri-n-butylphosphate have been determined in this manner. It has been demonstrated for the first time that the equilibrium constants for liquid-liquid extractants can be determined in a facile manner using ICP.

Purification of wet process phosphoric acid by solvent extraction with isoamyl alcohol. part i. liquid-liquid equilibrium of the water-phosphoric acid-isoamyl alcohol at 25°c.

Abstract: Solubility and liquid-liquid phase equilibrium data have been measured for the ternary system Water-Phosphoric Acid-Isoamyl Alcohol at 25⪚C. Data for the binodal curve have been determined by the cloud point method. Data for the tie lines have been obtain ed by analyzing the phosphoric acid percent in both aqueous and organic phases. The experimental plait point has been calculated by the Hand and Coolidge and Sherwood methods

CALORIMETRIC STUDIES OF THE SYNERGISTIC EFFECT. THE REACTION OF UO2 2+, Th 4+ AND Nd 3+ TTA COMPLEXES WITH TBP AND TOPO IN BENZENE

Abstract: Titration calorimetry was used to investigate the thermodynamics (ΔG, ΔH, ΔS) of the addition reactions between M(TTA)n(H2O)m (where M = UO2 2+, Th4+, Nd3+) and TBP or TOPO in dry and in water saturated benzene solvent. The adduct species formed were UO2((TTA)2 S, Th(TTA)4 S, and Nd(TTA)3 Sn (n = 1,2).The thermodynamic values complemented by water analysis data, allow evaluation of the relative importance of enthalpic and entropic contributions of ΔG, of the role played by water and of the changes in coordination number which occur during the reactions with the adduct ligands.

Separation of phenols from dilute aqueous solution by use of tri-n-octyl phosphine oxide as extractant

Abstract: Trioctyl phosphine oxide (TOPO) is examined as an extractant for phenol and other phenolic compounds. Equilibrium distribution coefficients have been measured for extraction of phenol, dihydroxybenzenes, and trihydroxybenzenes by solvents composed of TOPO in various diluents. Results are interpreted in terms of a model based upon complexation stoichiometry, allowing for solvation of uncomplexed solute as well. TOPO is a strong complexant for all the phenolic solutes studied. The nature of the diluent has a significant effect upon distribution coefficients, and in the case of an alcohol diluent reduces the distribution coefficient for phenol considerably. The degree of complexation remains appreciable at temperatures which would be used for regeneration of phenol by distillation. This makes it necessary to use a diluent boiling at least 70°C to 80°C higher than the boiling point of phenol, which is 182°C. Regeneration studies are reported for isobutyl heptyl ketone, dimethyl naphthalene, and a mix...

The selectivity of nickel over iron in the lix63-hdnns solvent extraction system

Abstract: The effects of the aqueous phase pH and the organic phase HDNNS concentration on the distribution coefficients of Ni and Fe in pure HDNNS or mixed LIX63-HDNNS systems have been investigated. With the mixed extractants, there is antagonistic extraction of iron below pH 1.4 whereas synergistic extraction occurs above this pH. At pH 2.5 and a fixed LIX63 concentration, iron distribution increases markedly in comparison with the oxime-free system and goes through a maximum with increase in HDNNS concentration. A similar behavior is shown by nickel at both pH 1.0 and 2.5. The log DFeversus pH plot gives a curve with a slope of two for the LIX63-HDNNS mixed system, which suggests that iron is extracted in the form of a species with an ionic charge of 2, probably Fe(OH)2+. The extracted complexes are proposed as Ni(H2L)3D2where all three oxime molecules function as bidentate ligands, and Fe(OH) (H2L) 3D2where one of the oxime molecules functions as a monodentate ligand. The Ni/Fe selectivity is high at ...

SYNERGIC EXTRACTIONS OF INDIUM(III) FROM CHLORIDE AND PERCHLORATE MEDIA WITH 1-PHENYL-3-METHYL-4-ACYLPYRAZOL-5-0NES AND TRI-n-OCTYLPHOSPHINE OXIDE MIXTURES IN TOLUENE

Abstract: The synergic mixtures of extractants HL + TOPO where HL = l-phenyl-3-methyl-4-acylpyrazol-5-one, acyl = benzoyl (HPMBP), thenoyl (HPHTP), lauroyl (HPMLP) and with TOPO = tri-n-octylphos-phine oxide, are studied by IR, PMR and 31P NMR spectroscopies and by liquid-liquid distribution analysis. In toluene solutions, the “acylpyrazolones” are, in fact, chelated 4-acyl-5-hydroxy-pyrazoles ; addition of TOPO weakens this intramolecular H-bond by formation of H-bonded (TOPO.HL) complexes (log Kc -˜, 1.1) ; the chelate ring may be broken (HPHTP) or subsist (HPMBP, HPMLP) in these complexes. Solid HPMBP exists either as chelated 4-acyl-5-hydroxypyrazole (yellow solid, F = 92°C) or as “open” 4-acyl-5-hydroxypyrazole with strong intermolecular H-bonds (white solid, F = 1150C). Extraction of indium with the extraction solvents studied, from CI /C104aqueous solutions.takes place according to the four-equilibria (x = 0 to 3) : The constants Kxare determined : KO˜ K1> K2> K3; HPMBP is the best extractant in all...

Diluent effect on the extraction of uranium(vi) from hydrochloric acid solutions by trioctylamine

Abstract: The extraction of uranium(VT) and divalent metals (copper, zinc and cadmium) from hydrochloric acid solutions by trioctylamine (TOA) has been examined using various diluents such as benzene, chlorobenzene, o-dichlorobenzene, toluene, w-xylene, nitrobenzene, carbon tetrachloride, chloroform and 1,2-dichloroethanc. It is found that a parabolic dependence of the distribution coefficient on the solubility parameter of diluent is not observed in these extraction systems. The results obtained are investigated in comparison with the extraction of uranium(VI) and divalent metals by trioctylmcthylamraonium chloride (TOMAC) in organic solvents in which the distribution coefficient and the enthalpy change associated with the metal extraction can be expressed in terms of the solubility parameter of extractant, diluent and the complex formed in the organic phase and their molar volume by assuming a regular solution. Consequently, since the solutions of TOA-HCl in organic solvents arc not regarded as regular s...

Dissociation extraction : prediction of separation factor and selection of solvent

Abstract: A predictive method for the separation factor in dissociation extraction, using n-octanol as a solvent, is suggested. The extent of hydrogen bonding of the solute with the solvent and the steric hindrance to the functional group play sometimes a decisive role in deciding the extent of separation. This is illustrated by an analysis of some model systems.

Glycine enhanced separation of Co(II) and Ni(II) with bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) by liquid-liquid extraction and supported liquid membranes

Abstract: The extraction behavior of Co and Ni ions from aqueous nitrate solution containing glycine, and their separation by liquid-liquid extraction and supported liquid membranes (SLMs) has been studied. The separation factor between the two metals is greatly enhanced by the presence of glycine. The enhancement is due to the preferential complexation of the Ni ions by glycine. The conditional equilibrium constants of the extraction reactions and the SLM permeability coefficients have been measured. The results indicate that metal glycinate complexes are not extracted and that in presence of glycine very clean Co-Ni separation can be obtained in a single SLM pass.

MIXED LIGAND CHELATE EXTRACTION OF LANTHANIDES WITH N-m-TRIFLUOROMETHYLBENZOYL-PHENYLHYDROXYLAMINE SYSTEMS

Abstract: A study of the equilibrium extraction behavior of a series of representative tervalent lanthanide ions, Pr, Eu and Yb, was carried out with chloroform solutions containing N-benzoylphenylhydroxylamine, N-m-tri-fluoromethylbenzoylphenylhydroxylamine (HL)either alone or combined with 1,10-phenanthroline (phen). The results demonstrated that the lanthanides are extracted as LnL3-2HL or in the presence of phen as LnL3. HL phen for Pr and Eu, and LnL32phen for Eu and Yb, The extraction constants, separation factors, and composition of adduct complexes for the two extractants were compared.

The extraction of silver from cyanide solutions with ion exchange resins

Abstract: The ability of various ion exchange resins to extract silver from synthetic cyanide solutions was evaluated. It was found that weak base resins such as DUOLITE A-7, DOWEX WGR-2, DOWEX MWA-1, DOWEX XFS-4195, and AMBERLITE IRA-35 extract silver significantly only when the pH is lower than 8. At higher pH, the same resins exhibited little or no silver extraction. A comparison among weak base resins showed that DUOLITE A-7 and DOWEX MWA-1 have the best characteristics in terms of capacity and elution efficiency. Strong base resins such as DOWEX MSA-1 and AMBERLITE IRA-910 extract silver in the entire pH range from 4 to 12. When the aqueous feed solution contains only one metal, these resins have a significantly larger capacity for silver than for copper, iron or zinc. But, if one or more base petals are added to the cyanide feed solution, the silver extraction is depressed to an extent which depends on the contact time. The silver extraction can be maximized by decreasing the concentration of free cy...

Synergic extraction of cobalt(ii) by structurally related crown ethers and thenoyltrifluoroacetone

Abstract: Cobalt (II) was extracted from perchlorate aqueous media by thenoyltrifluoroacetone (HTTA)alone and mixed with 12-Crown-4 (12C4) 15-Crown-5 (15C5) 18-Crown-6 (18C6)dibenzo-18-Crown-6 (Dbl8C6)dicyclohexyl-18-Crown-6 (Dchl8C6) or dicyclohexyl-24-Crown-8 (Dch24C8), in chloroform. The extraction constant of the chelate (K20) the extraction constant of the mixed species (K21), the synergic factor (S.F.) and the formation constant of the extracted adducts (β21) were evaluated. The adduct stoichiometry was found to have the general formula Co(TTA)2CE, irrespective of the crown ether (CE) used. It was found that no specific cavity size is required for the adduct formation. The synergic values K21, S.F., and β21as related to the crown ether took the order Dch24C8 > 18C6 > Dchl8C6 > 15C5 > Dbl8C6 > 12C4, which could be explained in terms of the crown ether basicity rather than the correspondence between the cavity size of the crown ether and the cobalt(II) crystal radii. The sequence 18C6 > Dchl8C6 > Dbl8C...

Extraction equilibrium of mercury(ii) with a sulfur-containing carboxylic acid.

Abstract: The extraction behaviors of mercury(II) with dihexyl sulf ide(=DHS), 1,2-bis (hexylthio) ethane ( = BHTE) and ∝-butylthiolauric acid(= ∝-BTLA) from nitric acid and hydrochloric acid were compared at 30 ° C. It was found that in the case of the extraction from nitric acid, mercury(II) is almost quantitatively extracted by these extractants except DHS and that in the case of that from hydrochloric acids, the extractability for mercury(II) of these extractants was in the order:BHTE > DHS > ∝-BTLA. Further detailed studies were conducted in order to investigate the extraction behavior of ∝-BTLA for mercury(II) from chloride medium. It was clarified that ∝-BTLA does not behave as a cation-exchange extractant but as a solvating extractant owing to the strong affinity of a sulfur atom in ∝-BTLA to mercury(II), and that mercury(II) is extracted according to the following solvation mechanism by ∝-BTLA. Extraction equilibrium constant was evaluated as Ke=5.5(dm3/mol).

Purification of wet process phosphoric acid by solvent extraction with dibutyl ether. part ii. study of the impurities distribution

Abstract: The results obtained when studying the purification of wet process phosphoric acid wdith dibutyl ether are reported. Percent PA, and impurities: Fe, Al, Mg SO4 − and F− extracted into the organic phase are shown. The variation of the percent extracted in to the organic phase for the different components has been studied as a function of the PA wt% in the organic phase. Results have been compared with those corresponding to other solvents previously studied. Dibutyl ether shows good purification behaviour for metallic impurities and SO4 −, but seems to be not very suitable for F− purification due to its high F− extraction capacity.

Ion exchange behaviour of chelating resin dowex a-1with actinides and lanthanides

Abstract: Adsorption studies of several actinides and lanthanides have been carried out by chelating ion exchange resin Dowex A-1. The metal ions studied were Pu4+, Zr4+, UO2 ++, Am3+, Cm3+, Bk3+, Cf3+, Eu3+, and Tm3+. The separation factors between consecutive trivalent actinides and between Am(III) and Eu(III) have been evaluated. Mechanism of adsorption of actinides and lanthanides from different aqueous media has been discussed. An ion exchange procedure for the separation of Pu4+ and UO2 ++ has been developed using this resin.

Solvent extraction of zirconium(iv) mid uranium(vi) from chloride media with bidehtate schiff bases

Abstract: The systematic licuid-liquid extraction behaviour of zlrconium(IV)and uranium(VI) with bidentate Schiff bases (HSB) in benzene as the diluent has been studied. Quantitative extraction of zirconium(IV)has been achieved. Four consecutive extractions are, however, necessary for quantitative extraction of uranium(VI) at pH 6.0. The extracted species seem to be [Zr4(OH)8(H2O)4(HSB)6]Cl8and [(UO2)2(OH)2(HSB)[Cl2.The extraction efficiency is in the order : Zr4+> Th4+UO2 2+. It is possible to separate zirconium from thorium and uranium by solvent extraction with HSB. Exchange reaction technique has been employed for separation of thorium and uranium.

EXTRACTION OF Ni(It) BY DI-(2-ETHYLHEXlfL)PHUSPHOKIC ACID DISSOLVED IN TOLUENE

Abstract: The extraction of Ni(II) from 1.0 mol-dm-3aqueous NaNO3medium by di-(2-ethylhexyl) phosphoric acid (HDEHP) dissolved in toluene has been studieo as a function of the total extractant concentration, the equilibrium pH and the total raetal concentration in the aqueous phase. Nickel distribution data have been interpreted in terms of the formation of NiR2(HR)2, and NiR2species in the organic phase in the low pH range anc by the formation of Na-HUEHP micelles, due to the neutralization of the reagent in the organic phase, and the further exchange of Na+by Ni2+in these micelles in the high pH range for each of the total extractant concentrations used.

Polynitrogen reagents, in metal separation. part 5 the extraction of uranium(vi) from sulphuric, nitric and hydrochloric acid media with alkyldiamhonium extractants.

Abstract: A variety of a1kyldiammonium extractants (tertiary and quaternary) were used to extract uranium(VI) from sulphuric, nitric and hydrochloric acid media. The performance of these extractants was compared with that of Aliquat-336 and Alamine-336. Extractions from dilute uranium(VI) solutions were carried out in order to simulate conditions employed in the local mining industry

Study of kinetic factors affecting the efficiency of separation of transplutonium and rare-earth elements during the extraction by di-(2-ethylhexyl) phosphoric acid

Abstract: The kinetics of the extraction of transplutonium and rare-earth elements with HDEHP from solutions of different complex-forming reagents has been studied. The possibility of the Improvement of intragroup separation of these elements with the use of dynamic factors has been demonstrated

Speciation study on the ion exchange extraction of silver, copper, iron and zinc cyano complexes with an iterative slope analysis technique.

Abstract: A slope analysis technique was developed and applied to the study of various equilibrium distribution isotherms in order to determine the speciation involved in the ion exchange. The slope analysis technique consisted of a computer iterative procedure to estimate the equilibriura resin composition and the introduction of ‘macro’ concentrations of a foreign anion to induce limiting conditions. The results indicate that, under the experimental conditions and with tht resi.is studied, both copper and ziac are extracted mainly as bivalent ions. Evidence was found that iron is extracted as a tetravalent ion whereas silver appears to be extracted as a mixture of mono- and bivalent ions.

Extraction kinetics of hydrochloric acid by trilaurylamine at different ionic strengths

Abstract: The kinetics of extraction of hydrochloric acid by trilaurylamine dissolved in toluene was investigated as a function of the ionic strength, using lithium chloride, ranging from 0.2M to 3M with a stirred Lewis cell. The rate of acid extraction was found to decrease by increasing the concentration of the supporting electrolyte. The results were explained in terms of a mixed regime (chemical reaction + diffusion).