Mechanism Of Solvent Extraction Research Articles

Jet-Injection In Situ Production of PVDF/PCM Composite Fibers for Thermal Management.

Thermal management protects against external agents and increases the lifetime and performance of the devices in which it is implemented. Because of their ability to store and release a high amount of energy at a nearly constant temperature, phase change materials (PCMs) are promising thermoregulatory materials. Thus, the manufacture of PVDF fibers containing PCMs has advantages since PVDF is already used in elements that are susceptible to thermal management as a binder in batteries or as a base material for fabrics. This work presents a simple, versatile, in situ, cost-effective, and easy-to-scale-up method to produce PVDF-based fibers containing paraffin RT-28HC for thermal management. To achieve that goal, the microfluidic approach of coaxial flows was simplified to gravity-aided laminar jet injection into a bulk fluid, where fibers were produced by the solvent extraction mechanism. With this methodology, hollow PVDF fibers and core-shell PVDF fibers containing paraffin RT-28HC have been produced. The proposed approach resulted in fibers with up to 98 J/g of latent heat, with a hierarchical porous structure. SEM study of the fiber morphology has shown that PCM is in the form of slugs along the fibers. Such PCM distribution is maintained until the first melting cycle, when molten PCM spreads within the fiber under capillary forces, which was observed by an infrared camera. Manufactured composite fibers have shown low thermal conductivity and high elasticity, which suggest their potential application as a thermal insulation material with thermal buffer properties. Leakage tests revealed outstanding retention capacity with only 3.5% mass loss after 1000 melting/crystallization cycles. Finally, tensile tests were carried out to evaluate the mechanical properties of the fibers before and after thermal cycling.

Solvent extraction of superfine pulverized coal. Part 3. Small angle X-ray scattering characterization

Because of the unique physicochemical textures induced by reduced particle size, superfine pulverized coal presents attractive characteristics in different utilization processes, including solvent extraction. In this work, the synchrotron radiation-based small angle X-ray scattering (SAXS) with high precision was used to quantitatively characterize all the products during the coal extraction process, including raw coal, extract, and residue. In addition, the evolutions of pore structures (solid state) and aggregate configurations (liquid state) were focused on. The results show that the fractal dimensions of pore surfaces are mainly related to the pore sizes and corresponding quantity distributions. When the particle size is less than 14 μm, the comminution induced mechanical effect on the pore surface gradually changes from impact to polish during the superfine grinding. Additionally, the fractal dimension decreases with the decline of particle size and ash content, whilst increases for the lower ranked coals. As for the extraction process, the extraction effect of tetrahydrofuran on anthracite coal is relatively better, while pyridine is more effective for bituminous coal. The diverse driving force caused by particle size effect leads to different radii of the gyration of the extracted aggregates, indicating the selected bituminous coal has active sites that are susceptible to reacting with aromatic compounds, while anthracite has a large number of active sites that accept electrons. Finally, the surface fractal dimension of the extraction residue declines about 2% and 4% for HN and NMG coal respectively, and the decreasing trend declines for larger coal particles. Interestingly, this decreasing trend of bituminous coal is more evident, which indicates the pore surface of bituminous coal is easier to react with solvent. The research sheds light on thoroughly depicting the pore structure of coal and residue at a molecular level, which promotes a better understanding of the solvent extraction mechanisms. The results also provide a new perspective for constructing more comprehensive coal molecular models in the future.

Solvent extraction of superfine pulverized Coal. Part 4. Carbon skeleton characteristics

To better understand the molecular structure of superfine pulverized coal and promote its practical utilization, the NMR (nuclear magnetic resonance) technology is adopted to study the structural information of all the products from the solvent extraction process, including raw coal, residue, and extract. The whole set of NMR spectra is resolved into different individual curves with specific linewidths, shapes, and intensities. According to the chemical shift, the carbon skeleton characteristics like the aromaticity, cluster size, and other structural lattice parameters are analyzed in detail. More importantly, the influences of coal maturity, coal size, and solvent on the carbon structural evolution during the extraction process are focused on. The results show that the aromatic ring stacking and aromatic ring exposure and fragmentation occur competitively during the superfine comminution, promoting the structural evolution of the coal. In addition, aliphatic carbon transfers more from raw coal into the extract than aromatic carbon in the whole extraction process, which is accompanied by the disappearance of carbonyl groups. Furthermore, the reduction of particle size can promote the extraction effect of the extractant on the coal powder, and reduce the proportion of aliphatic carbon in the residue. The work introduces the correlations among the raw coal, residue and extract from a carbon skeleton point of view, providing a reference for elucidating the solvent extraction mechanisms. The results shed light on better understanding the coal structure and its further molecular modeling.

Structural effects of benzene-centered tripodal diglycolamides on extraction of trivalent f-cations into a room temperature ionic liquid

A series of three benzene functionalized tripodal diglycolamide (DGA) extractants (abbreviated as Bz-T-DGA, and termed as LI, LII and LIII) were studied for their extraction abilities for Eu3+ and Am3+ ions. Extraction efficiencies of these ligands are distinctly dependent on: (i) the nature of alkyl substituents on amidic N atoms of DGA, (ii) alkyl chain length that connects the DGA moeties with the benzene ring, and (iii) the medium of extraction. Substitution of protons with iso-pentyl groups on DGA nitrogen atoms enhanced the ligand extraction efficiency many folds. At the same time, increasing the spacer atoms between the benzene platform and the DGA units reduced the ligand extraction efficiency. The distribution ratio of Eu3+ was higher than that of Am3+ with all the three ligands, but the separation factor between the two elements was less than 2. Solvent extraction mechanism was entirely different when the organic solvent changed from n-dodecane (a molecular solvent) to ionic liquid. DFT calculations revealed that the solvent extraction abilities of these ligands were primarily goverened by their complexation abilities for trivalent f-cations.

Research on treatment of oil-based drill cuttings based on ionic liquids synergistic solvent extraction

The method of solvent extraction has a good application prospect in the treatment of oil-based drill cuttings, but the existing extractants have the high potential safety hazards of a low flash point and volatility. Therefore, this article proposes to use an ionic liquid with improved safety and strong extraction capacity to treat oil-based drill cuttings through a collaborative solvent extraction method. The extraction effect of different extractants and different ionic liquid synergistic extractants were studied, respectively. The research results showed that [IM18, H2]Br ionic liquid has a good synergistic effect with n-butanol, and the extraction rate could reach 99.14%. The experimental conditions were that the mass ratio of [IM18, H2]Br to n-butanol was 1:10, extraction time was 40 min, and the mass ratio of drill cuttings to extractant was 1:3. Under these experimental conditions, the mixed extractants can be recycled 3 times. The closed flash point of extractants increased from 35 °C to 53 °C, and the boiling point of extractants decreased from 117 °C to 90–107.3 °C. Based on this, the mechanism of ionic liquids synergistic solvent extraction was discussed.

Solvation-Anionic Exchange Mechanism of Solvent Extraction: Enhanced U(VI) Uptake by Tetradentate Phenanthroline Ligands.

Phenanthroline diamides (L) demonstrated a unique ability to extract uranium from nitric acid solutions into a polar organic solvent forming complexes of 1:2 stoichiometry as tight ion pairs {[UO2LNO3]+[UO2(NO3)3]-} by a novel extraction mechanism, which is a combination of two already well-known mechanisms: solvation and ion-pair anion exchange. A UV-vis study was used to confirm the formation of such complexes directly in the organic phase. Moreover, chemical synthesis and single crystal growth were performed to confirm unambiguously the structure of the complexes in the solid state.

Study on Solvent Extraction of Rare Earth Elements from Leaching Solution of Coal Fly Ash by P204

Due to the increasing demand for rare earth elements (REE) resources in the market and the shortage of their direct sources, the research on REE in coal fly ash (CFA) has attracted the increasing attention of scholars because of its high content of rare earth. To extract and separate REE from the leaching solution of CFA, the method of solvent extraction after acid leaching is usually adopted. In this paper, the leaching solution of coal fly ash from Panbei, south China, with an average REE content of 478 μg/g, was taken as the research object. The extracted di-2-Ethylhexyl phosphonic acid (P204) was used to explore the solvent extraction effect and mechanism. When performed with the conditions: pH value of 2.1, oil-water ratio (O/A) of 1, extraction time of 25 min, solvent concentration of 6% and temperature of 30 ℃, the extraction rates of La, Ce, Pr, Nd, and Y were 89.16%, 94.11%, 95.56%, 96.33%, and 99.80%, respectively. It was indicated that the P204 extraction system separated REE well from the aqueous phase. The structure of the extraction complex was deduced by taking yttrium as an object of analysis, and the extraction mechanism equation was determined by using the slope method. In this extraction system, the molecular formula of the complex is YCl2(HA2) and the enthalpy change (△H) is +86.68 kJ/mol, which provides theoretical guidance for the extraction of REE in industrial production.

Ionic liquids enhanced oil recovery from oily sludge-experiment and mechanism

The oily sludge would cause environment pollution, and would cause the heavy oil waste. Therefore, it was vital for us to find novel methods to obtain heavy oil from the oily sludges. In this study, the [C12mim][PF6] and [C12mim][Br] ionic liquids(ILs) were used to enhance the oil recovery. The toluene could obtain the highest oil recovery, and both the two ILs could increase the oil recovery. Toluene could obtain the highest oil recovery (89.4 wt%), and n-octane could obtain the lowest oil recovery (76.8 wt%). [C12mim] [PF6] could efficiently increase the heavy oil recovery to 91.2 wt%(by toluene). The [C12mim][Br] could increase the heavy oil recovery further. Both the [C12mim] [PF6] and the [C12mim][Br] ionic liquids could increase the heavy ois C/H ratio, decrease heavy oil viscosity and increase the sands hydrophilicity. The [C12mim][Br] ionic liquids showed better effect. In addition, the ionic liquids could increase the solvents recovery, and the ionic liquids recovery were high. Therefore, the ionic liquids enhanced oil recovery could be recycled to ten times. The two ionic liquids could effectively decrease the heavy oil interaction force, and when the ionic liquids increased to 200 ppm, the force remained stable. In the end, the ionic liquids enhancing solvent extraction mechanism was put forward.

Mechanism analysis of solvent selectivity and energy-saving optimization in vapor recompression-assisted extractive distillation for separation of binary azeotrope

Octane and p-xylene are common components in crude gasoline, so their separation process is very important in petroleum industry. The azeotrope and near azeotrope are often separated by extractive distillation in industry, which can realize the recovery and utilization of resources. In this work, the vapor–liquid equilibrium experiment was used to obtain the vapor–liquid equilibrium properties of the difficult separation system, and on this basis, the solvent extraction mechanism was studied. The mechanism of solvent separation plays a guiding role in selecting suitable solvents for industrial separation. The interaction energy, bond length and charge density distribution of p-xylene with solvent are calculated by quantum chemistry method. The quantum chemistry calculation results and experiment results showed that N-formylmorpholine is the best solvent among the alternative solvents in the work. This work provides an effective and complete solvent screening process from phase equilibrium experiments to quantum chemical calculation. An extractive distillation simulation process with N-formylmorpholine as solvent is designed to separate octane and p-xylene. In addition, the feasibility and effectiveness of the intensified vapor recompression assisted extraction distillation are also discussed. In the extractive distillation process, the vapor recompression-assisted extraction distillation process is globally optimal. Compared with basic process, the total annual cost can be reduced by 43.2%. This study provides theoretical guidance for extractive distillation separation technology and solvent selection.

Ionic-liquid-enhanced solvent extraction mechanism: A novel concept

Solvent extraction has been widely used to obtain bitumen from oil sands. In addition, several methods have been used to enhance solvent extraction processes, including the use of ionic liquids. Although a variety of ionic liquids has been used to enhance bitumen recovery, the detailed mechanism is still unclear, while many proposed mechanisms are in fact contradictory. In this study, the solvent extraction mechanism was studied through the evaluation of the role of ionic liquids on the internal properties of heavy oil, as well as in the modification of the oil–solid and oil–water interfaces. The internal properties investigated include the C/H ratio, heavy oil viscosity, and the levels of saturates, aromatics, resins, and asphaltenes (SARA) present. Herein, using the ionic liquids results in a significant increase in the C/H ratio of the heavy oil, as well as the resins and asphaltene content, while the heavy oil viscosity decreases significantly. The ANOVA analysis and Tukey test showed that most ionic liquids-solvent extraction have significant effect on altering the heavy oil recovery, C/H ratio, viscosity and SARA content comparing to solvent alone extraction. It can, therefore, be concluded that ionic liquids are able to modify the oil–solid interface, making the sand surface increasingly hydrophilic, while a similar modification of the oil–water interface results in the decrease of the oil–water interfacial tension with increasing ionic liquid concentration. In addition, when the ionic liquid concentration increases, the zeta potential of CaCO3 in the ionic liquids decreases, whereas the zeta potential of the heavy oil in the ionic liquids increases (absolute value decrease), and then the electrostatic attraction between heavy oil and CaCO3 decreased. The AFM results showed that the ionic liquids could decrease heavy oil–solid interaction forces, and forces decreased with the ionic liquids concentration. The ionic liquids could further be recycled effectively, without significantly decreasing the oil recovery. Finally, ionic liquid adsorption isotherms were fitted employing the Langmuir, Freundlich, and Temkin models, obtaining excellent goodness-of-fit values. However, when the linear model was employed, the goodness-of-fit was poor. The ionic liquid adsorption kinetics further exhibited good fits to pseudo-first and pseudo-second order models. Herein, the increased adsorption of the ionic liquids on calcite surfaces corresponded to low oil recoveries.

Aggregation of Bifunctional Extractants Used for Uranium(VI) Separation.

DEHCNPB (butyl-N,N-di(2-ethylhexyl)carbamoyl-nonylphosphonate) is an amido-phosphonic acid that has remarkable properties for the separation of uranium from wet phosphoric acid. Despite previous studies, a detailed description of the DEHCNPB organic solutions at the supramolecular and molecular scales is missing. In the present work, we use classical Molecular Dynamics (MD) combined with SANS and SAXS experimental data in order to describe the aggregation of the bifunctional extractant DEHCNPB as well as the speciation of uranium(VI) in such systems. We provide a fine description of the molecular species in the organic solution and of the interactions within the aggregates formed, shedding light on solvent extraction mechanisms. Without uranium, the organic phase is highly composed of dimers and trimers H-bonded through phosphonate functions and without water molecules. With uranium, two to three extractant molecules coordinate directly the uranyl cation by their phosphonate groups. Uranyl is not fully dehydrated in this organic solution, and the amide groups of the extractants are found to form H-bonds with the water molecules bound to uranyl. These H-bond networks around the metallic cation stabilize the complexes and facilitate the extraction. These results underline the importance of considering weak interactions in the understanding of extraction processes and demonstrate how molecular simulations provide essential insights into such complex organic phase chemistry with a high number of species.

Recovery of iron by jarosite crystallization and separation of vanadium by solvent extraction with extractant 7101 from titanium white waste liquid (TWWL).

The jarosite crystallization and new extractant system for extractant 7101 was used to separate iron and extract vanadium from titanium white waste liquid (TWWL). The influence factors and mechanisms of crystallization and solvent extraction were investigated and analyzed using SEM-EDS, XRD, FT-IR, solution thermodynamic theory and extraction isothermal curve. More than 97% of iron was precipitated with the following conditions: potassium chlorate 15 g/L, pH value of 1.6, temperature of 95 °C and time of 90 min, in which the crystallization product was jarosite with a purity of 99.5%; the pH value of the solution decreased after precipitation. The extraction efficiency of vanadium reached 88.6% with 10% Fe, 5% Al(III) but less for Mg(II), K(I) and Na(I) under the conditions X7101 of 0.5, pH value of 2.0, time of 4 min and stirring speed of 40 r/min. The extraction of metal ions occurred in the order V(V) > Fe(III) > Al(III) > Mg(II) > K(I). Vanadium minimally existed as H2V10O284- at pH 2.0, and the functional groups NH and C-N contributed to vanadium extraction using the extractant 7101. Four stages extraction and three stages of re-extraction were predicated by McCable-Thiele plots.

Electrosynthesis of titanium dioxide from sulfate leach liquors using solvent extraction/electrochemical deposition process

ABSTRACT The primary goal of this study was the development of a recycling process to recover titanium from real sulfate leach liquors prepared from the tailings of uranium processing mine. Preparation and characterization of pure TiO2 powders using; a clean, cheap, and low-temperature combined solvent extraction/electrochemical deposition technique were reported. Solvent extraction using di(2-ethylhexyl) phosphoric acid in kerosene allowed the selective recovery of Ti (IV) from the leach liquor containing Fe, Mn, and Zr impurities. All of the Ti was extracted selectively using 20% D2EHPA/kerosene under organic/aqueous phase ratio of unity in presence of L-ascorbic acid. The equilibrium in 8.5 M sulfuric acid is established within 60 min. Subsequently, Ti was recovered from the loaded organic phase using mixtures of HCl and H2O2 solutions. The preparation of TiO2 powders by cathodic electrodeposition was optimized. A combination of X-ray diffraction and dynamic light scattering analysis had been used to confirm the formation of TiO2 nanoparticles. Finally, the solvent extraction and electrodeposition mechanisms were discussed, and the resultant products were characterized by several techniques.

Insight into the Deep Eutectic Solvent Extraction Mechanism of Flavonoids from Natural Plant

Deep eutectic solvents (DESs) are a new class of green solvents with potential applications for the extraction of target compounds from both liquid and solid samples. However, current research in t...

Effect of Counteranions on the Extraction and Complexation of Trivalent Lanthanides with Tetradentate Phenanthroline-Derived Phosphonate Ligands.

Soft-hard-donor-combined ligands are a type of promising extractant for actinide and lanthanide separation. In this work, the effects of counteranions (Cl-, NO3-, and ClO4-) on the extraction and complexation behaviors of a recently reported tetradentate phenanthroline-derived phosphonate (POPhen) ligand toward lanthanides were thoroughly investigated using solvent extraction, NMR titration, UV-vis titration, and single-crystal X-ray diffraction measurements. It is found that C4-POPhen showed excellent extraction and selectivity toward heavy lanthanides [Lu(III)] compared to light lanthanides, particularly with the counterion of ClO4- and at low acidity. NMR titration studies demonstrated that both 1:1 and 1:2 Lu(III)/C4-POPhen complexes were formed in a CD3OD solution with all three counteranions and the 1:2 species was easier to form in a complexation of C4-POPhen with Lu(ClO4)3 under the same conditions. Furthermore, the stability constants of Nd(III) complexation with C4-POPhen in the counteranions of Cl-, NO3-, and ClO4- systems were determined through UV-vis titration, and a much larger value of log β of complexes was found in the ClO4- system, which was in good agreement with the results of solvent extraction. In addition, the structures of C2-POPhen complexation with Ln(NO3)3/Ln(ClO4)3 in the solid state were clearly unraveled by the single-crystal X-ray diffraction technique. This work demonstrated that the solvent extraction and complexation mechanisms of POPhen ligands with Ln(III) were significantly affected by the counteranions from both the solution and solid-state aspects, which might shed light on the lanthanide/actinide separation.

Cation Effect of Chloride Salting Agents on Transition Metal Ion Hydration and Solvent Extraction by the Basic Extractant Methyltrioctylammonium Chloride.

The addition of a nonextractable salt has an important influence on the solvent extraction of metal ions, but the underlying principles are not completely understood yet. However, relating solute hydration mechanisms to solvent extraction equilibria is key to understanding the mechanism of solvent extraction of metal ions as a whole. We have studied the speciation of Co(II), Zn(II), and Cu(II) in aqueous solutions containing different chloride salts to understand their extraction to the basic extractant methyltrioctylammonium chloride (TOMAC). This includes the first speciation profile of Zn(II) in chloride media with the three Zn(II) species [Zn(H2O)6]2+, [ZnCl3H2O]−, and [ZnCl4]2–. The observed differences in extraction efficiency for a given transition metal ion can be explained by transition metal ion hydration due to ion–solvent interactions, rather than by ion–solute interactions or by differences in speciation. Chloride salting agents bearing a cation with a larger hydration Gibbs free energy reduce the free water content more, resulting in a lower hydration for the transition metal ion. This destabilizes the transition metal chloro complex in the aqueous phase and increases the extraction efficiency. Salting agents with di- and trivalent cations reduce the transition metal chloro complex hydration less than expected, resulting in a lower extraction efficiency. The cations of these salting agents have a very large hydration Gibbs free energy, but the overall hydration of these salts is reduced due to significant salt ion pair formation. The general order of salting-out strength for the extraction of metal ions from chloride salt solutions is Cs+ < Rb+ < NH4+ ≈ K+ < Al3+ ≈ Mg2+ ≈ Ca2+ ≈ Na+ < Li+. These findings can help in predicting the optimal conditions for metal separation by solvent extraction and also contribute to a broader understanding of the effects of dissolved salts on solutes.

“Super moiety”-phosphoramidate in task-specific ionic liquids for effcient thorium separation through hybrid interaction

Replacing conventional solvents by ionic liquids is a promising route to greener nuclear fuel cycles. Here, we report a unique multi-functional task-specific ionic liquid (TSIL) for the extraction and separation of trace thorium (Th). The phosphoramidate substituted butyl groups to imidazolium ionic liquid (PN-TSIL) shows superior extraction ability and selectivity (distribution rations of Th ~ 8302 and separation factor of Th to uranium (U) ~ 793 at 2 mol/L HNO3). For industial application purpose, an extraction chromatographic resin perpared by PN-TSIL (called PN-TSIL Resin) was made to develop a rapid, highly specific separation technique for simulative 229Th/233U separation process. Moreover, combination of spectroscopic investigations, quantum-mechanical calculations and thermodynamic parameters mearsurment, an unprecedented resolution picture of extraction process was delineated. The extraction ability and selectivity of thorium could be explained by the multiple binding sites though hybrid interactions (coordination and hydrogen bond) between thorium and PN-TSIL, leading to an entropy-driven extraction process. The understanding of solvent extraction mechanism in molecular scale will inspire new ways for TSIL design for nuclear fuel cycles.

Lithium recovery from Li3PO4 leaching liquor: Solvent extraction mechanism of saponified D2EHPA system

Recovery of low-concentration lithium resources by Li3PO4 precipitation is an effective method and using saponified D2EHPA-kerosene is a promising method for the treatment of Li3PO4. In this paper, the effects of additives on the extraction of lithium from Li3PO4 leaching liquor and the mechanism of lithium extraction by saponified D2EHPA were investigated. The results showed that the addition of tributyl phosphate (TBP) could promote lithium stripping. Experiments confirmed that lithium in solution could be extracted by one-to-one cation exchange with sodium in the organic phase. Slope analysis showed that LiR·NaR was formed when lithium was extracted by saponified D2EHPA, and LiR·NaR·0.1TBP was formed when adding TBP (R is D2EHPA anion). Infrared spectroscopy indicated that the addition of TBP or the saponification of the organic phase depolymerized the D2EHPA dimer. Adding TBP improved lithium's stripping ratio and the concentration of lithium in the stripping solution, which are favorable to the subsequent Li2CO3 precipitation process. This paper provides a deeper understanding of the conversion of lithium phosphate to lithium carbonate using a saponified D2EHPA system.

Non-aqueous solvent extraction of indium from an ethylene glycol feed solution by the ionic liquid Cyphos IL 101: speciation study and continuous counter-current process in mixer-settlers.

A solvometallurgical process for the separation of indium(iii) and zinc(ii) from ethylene glycol solutions using the ionic liquid extractants Cyphos IL 101 and Aliquat 336 in an aromatic diluent has been investigated. The speciation of indium(iii) in the two immiscible organic phases was investigated by Raman spectroscopy, infrared spectroscopy, EXAFS and 115In NMR spectroscopy. At low LiCl concentrations in ethylene glycol, the bridging (InCl3)2(EG)3 or mononuclear (InCl3)(EG)2 complex is proposed. At higher lithium chloride concentrations, the first coordination sphere changes to two oxygen atoms from one bidentate ethylene glycol ligand and four chloride anions ([In(EG)Cl4]−). In the less polar phase, indium(iii) is present as a tetrahedral [InCl4]− complex independent of the LiCl concentration. After the number of theoretical stages had been determined using a McCabe–Thiele diagram for extraction by Cyphos IL 101, the extraction and scrubbing processes were performed in lab-scale mixer–settlers to test the feasibility of working in continuous mode. Indium(iii) was extracted quantitatively in four stages, with 19% co-extraction of zinc(ii). The co-extracted zinc(ii) was scrubbed selectively in six stages using an indium(iii) scrub solution. Indium(iii) was recovered from the loaded less polar organic phase as indium(iii) hydroxide (98.5%) by precipitation stripping with an aqueous NaOH solution.

Kinetics and mechanisms of solvent extraction and separation of La(III) and Ni(II) with DEHPA in petrofin

Abstract The kinetics of extractive separation of La(III) and Ni(II) from nitrate medium in the presence of lactic acid (HLac) using di-2-ethylhexyl phosphoric acid (DEHPA) diluted in petrofin was investigated using a cell with constant interfacial area and continuous stirring. The effects of stirring speed, interfacial area, pH, HLac concentration, extractant concentration, concentrations of metal ions and temperature on the extraction rate were examined. Results suggested that the extraction regime is diffusion-controlled. The reaction which occurred at the interface was found to be the rate-determining step. The extraction rates of both metal ions are found to be independent of pH. The extraction rates of La(III) and Ni(II) are first-order dependent with respect to lactic acid and metal ions (La(III) and Ni(II)) concentrations. The extraction rate of La(III) is first-order dependent on DEHPA concentration and for Ni(II), it varies to the power of 1.5. The separation of La(III) and Ni(II) from nitrate solution is possible at low interfacial area and low stirring speed.