Solvent Extraction Process Research Articles

Separation and recovery of titanium and scandium from the red mud

In this study, a full process in recovery of titanium and rare earth elements (REEs) from the red mud was developed. The suggested route consists of four main stages in the process flow diagram: sample preparation, leaching, hydrolysis, and solvent extraction. Sample preparation is proposed using a two-stage water washing followed by calcination to remove the acid-consuming components of the red mud. Dissolution of the Ti and REEs (with a focus on Sc) was developed using sulfuric acid followed by a hydrolysis process for the titanium precipitation. Concentration of the REEs in the solution was performed using a solvent extraction process. The dissolution efficiency of Ti and Sc were found 91 % and 93 %, respectively. Ti precipitation efficiency was about 86 %, and the final TiO2 product had a purity of 92 %, with the main impurities of a mixed iron and titanium oxide. After recovering Ti, Sc concentration using solvent extraction was studied. Using D2EHPA and alkaline stripping, Sc was concentrated from 69 ppm in the red mud to 1125 ppm in the obtained precipitate. The proposed process has the potential to be considered industrially due to its relative simplicity, high recovery yield, integrity, and utilization of low-cost reagents.

Short-Process Preparation of High-Purity V2O5 from Shale Acid Leaching Solution via Chlorination

The conventional V2O5 preparation processes include ion exchange, chemical precipitation, solvent extraction, and other processes. Given the long process and complex operation nature of traditional V2O5 production methods, we herein developed a short-process, low-temperature, and convenient operation method of isolating vanadium (in the form of V2O5) from shale acid leaching solution. The acid leaching solution was oxidized with NaClO3 and pH-adjusted with NaOH to form a vanadium-containing precipitate, which was mixed with AlCl3 (V:AlCl3 = 1:5, mol/mol) and roasted for 120 min at 170 °C to afford vanadium oxytrichloride (VOCl3) with a purity of 99.59%. In addition, the vanadium-containing precipitate was mixed with AlCl3 and NaCl (V:AlCl3:NaCl = 3:12:8, mol/mol/mol) and roasted for 120 min at 170 °C to afford VOCl3 with a purity of 99.94%. VOCl3 (purity of 99.94%) was dissolved in ultrapure water, and the solution (32 gvanadium/L) was treated with NH3·H2O (NH3:V = 1.34, mol/mol) at 50 °C for 120 min. The obtained precipitate (vanadium precipitation rate = 99.28%) was roasted at 550 °C for 3 h to afford high-purity vanadium pentoxide (V2O5) with a purity of 99.86%. Compared with the traditional hydrometallurgical method of V2O5 preparation, our method avoided solvent extraction and other undesired processes and the overall process flow is greatly shortened, thus having high practical value.

Optimization of green extraction process with natural deep eutectic solvent and comparative in vivo pharmacokinetics of bioactive compounds from Astragalus-Safflower pair

IntroductionNatural deep eutectic solvents (NaDESs) are promising not only in componential extraction, but also in drug delivery system due to their green and safe features. In this work, NaDESs were applied to extract bioactive components from Astragalus-Safflower pair, a classic traditional Chinese medicine combination. Furthermore, ready-to-use crude extracts were administrated to SD rats. MethodsTotal 9 NaDESs composed of food grade ingredients were screened for the extraction of representative 9 components (hydroxysafflor yellow A, anhydrosafflor yellow B, eleutheroside B, calycosin-7-O-glucoside, kaempferol-3-O-rutinoside, ononin, calycosin, astraganoside, and carthamin) from Astragalus-Safflower pair. Afterwards, genetic artificial neural network (GNN) was adopted for optimizing the ultrasound-assisted extraction process. After SD rats were orally administrated with the ready-to-use crude extracts extracted under the optimized conditions, the in vivo pharmacokinetic characteristics of 5 components were evaluated comprehensively from weight, gender, solvent and modeling surgery, under a well-established UPLC-MS/MS method. ResultsBetaine-Lactic acid (Bet-Lac) was eventually determined as the optimal extraction solvent for subsequent experiments. The optimal ultrasound assisted extraction process was as follows: 90 min of extraction time, 65 °C of temperature, 80% of Bet-Lac content and 50 mg/ml of solid-liquid ratio. Bet-Lac enhanced to varying degrees the bioavailability of analytes in normal and cerebral ischemia/reperfusion injured (CI/RI) rats in contrast with corresponding rats administrated with water extract groups (p < 0.05). Besides, the bioavailability of active components in CI/RI rat plasma was significantly lower than that in normal rats (p < 0.05), indicating pathological damage of CI/R had a significant impact on pharmacokinetic profile of compounds in rats. However, gender and body weight had no significant effects on the pharmacokinetic profile of bioactive components. ConclusionsNaDESs exhibited higher extraction efficiency than conventional solvents. And GNN is reliable to optimize the ultrasound assisted extraction process. This study supported the potential of non-toxic NaDESs as solvents for extraction process and drug delivery systems at the same time.

Solvent extraction of gold from a chloride-hypochlorite leached solution of waste printed circuit boards

ABSTRACT This study reveals the reclamation process of gold from a brine-leached solution of waste printed circuit boards (WPCBs) after the maximum leaching of base metals in a nitric acid medium. The brine leaching performed in the presence of hypochlorite yielded leach liquor of 152 ppm Au, 86 ppm, Cu, and 62 ppm Ni that underwent solvent extraction with tri-butyl phosphate (TBP) in Exxol D80. The gold extraction process was observed to be selective over base metal impurities, while the effect of TBP concentration, equilibrium pH, temperature, and organic-to-aqueous phase ratio was optimized. Experimental results showed the formation of complex into the extraction phase with the negative enthalpy change value of −98.7 kJ/mol. Thiosulphate mobilized stripping of gold from the loaded-TBP could give about 99% recovery efficiency of the solvent extraction process along with a good regeneration of the organic extractant to be re-used.

Relevance of Surface Adsorption and Aqueous Complexation for the Separation of Co(II), Ni(II), and Fe(III)

During the solvent extraction of metal ions from an aqueous to an organic phase, organic-soluble extractants selectively target aqueous-soluble ions for transport into the organic phase. In the case of extractants that are also soluble in the aqueous phase, our recent studies of lanthanide ion-extractant complexes at the surface of aqueous solutions suggested that ion-extractant complexation in the aqueous phase can hinder the solvent extraction process. Here, we investigate a similar phenomenon relevant to the separation of Co(II), Ni(II), and Fe(III). X-ray fluorescence near total reflection and tensiometry are used to characterize ion adsorption behavior at the surface of aqueous solutions containing water-soluble extractants, either bis(2-ethylhexyl) phosphoric acid (HDEHP) or 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEHEHP), as well as adsorption to a monolayer of water-insoluble extractant dihexadecyl phosphoric acid (DHDP) at the aqueous-vapor interface. Competitive adsorption of Ni(II) and Fe(III) utilizing either HDEHP or DHDP illustrates the essential feature of the recent lanthanide studies that the ion, which is preferentially extracted in liquid-liquid extraction, Fe(III), is found preferentially adsorbed to the water-vapor interface only in the presence of the water-insoluble extractant DHDP. A more subtle competition produces comparable adsorption behavior of Co(II) and Ni(II) at the surfaces of both HDEHP- and HEHEHP-aqueous solutions in spite of the known preference for Co(II) under solvent extraction conditions. Comparison experiments with a monolayer of DHDP reveal that Co(II) is preferentially adsorbed to the surface. This preference for Co(II) is also supported by molecular dynamics simulations of the potential of mean force of ions interacting with the soluble extractants in water. These results highlight the possibility that complexation of extractants and ions in the aqueous phase can alter selectivity in the solvent extraction of critical elements.

DEHP- extractant binding to trivalent lanthanide Er3+: Fast binding accompanied by concerted angular motions of hydration water.

Solvent extraction of trivalent rare earth metal ions by organophosphorus extractants proceeds via binding of phosphoric acid headgroups to the metal ion. Water molecules in the tightly bound first hydration shell of the metal ions must be displaced by oxygen atoms from phosphoric acid headgroups. Here, we use classical molecular dynamics simulations to explore the event in which a fully hydrated Er3+ binds to its first phosphoric acid headgroup. Approach of the headgroup into the region between the first and second hydration shells leads to a fast ejection of a water molecule that is accompanied by reordering of the hydration water molecules, including discretization of their angular positions and collective rotation about the metal ion. The water molecule ejected from the first shell is located diametrically opposite from the binding oxygen. Headgroup binding places a headgroup oxygen closer to Er3+ than its first hydration shell and creates a loosely bound water that subsequently exchanges between the first shell and its environment. This second exchange of water also occurs at discrete angular positions. This geometrical aspect of binding may be of relevance to understanding the binding and transport of ion-extractant complexes that are expected to occur at the organic-aqueous liquid-liquid interface used in solvent extraction processes.

Effect of synthesis routes on the microstructural properties of nano zero-valent metals of Fe and Cu synthesized from the industrial copper solvent extraction process

Nano zero-valent iron (NZVI) and nano zero-valent copper (NZVC) synthesizing from the present industrial solution could be attractive due to some advantages such as preparing advanced materials through cost-effective methods and solving their disposal problems. Moreover, the present microstructural investigation probed the influence of synthesis routes used on NZVI and NZVC properties. Accordingly, the microstructural properties of nano zero-valent metals (NZVMs) synthesized through the green and chemical methods were calculated by the Rietveld method. The obtained results verified that NZVI was synthesized with titrating NaBH4 and green tea extract by chemical and green techniques from the industrial raffinate solution. NZVC was prepared from the industrial Cu-enriched solution through green and chemical techniques by titrating ascorbic acid and NaBH4, respectively. XRD and Energy Dispersive Spectroscopy (EDS) proved that NZVMs were synthesized and fairly oxidized. Microstructural studies also revealed that the amorphization degree was increased from 62.2% and 2.7% in the green NZVI and NZVC to 89.8% and 86.81% in chemically synthesized NZVI and NZVC, respectively. Considering green NZVMs, the crystallite size and unit cell were reduced in chemically synthesized NZVMs. Also, the microstrain changed from 2.79E-4% and 3.2E-3% in the green NZVI and NZVC to 2.4E-2% and 6.2E-4% in chemically synthesized NZVI and NZVC, respectively. The findings of this study indicated that the chemically synthesized NZVMs had smaller particles, crystallite size, unit cells and a higher amorphization degree, in favor of reactivity promotion and oxidation progress.

Study of the Extraction Process of the Main Components of the Productive Solution (Copper, Iron and Silica) of the Almaly Deposit

The purpose of the research was to study the extraction of the main components of the productive solution of the Almaly deposit with oxyoxime extractants. As the practice of existing plants shows, one of the main drawbacks of the process when implementing the liquid extraction process at various fields is the formation and accumulation of a large volume of the third phase (crud), which leads to a slowdown, in some cases to a stop in the solvent extraction process, thereby reducing the efficiency of the entire production copper by SX-EW technology. One of the main factors leading to the formation of such a phase are harmful metal impurities, solid suspensions in the solution supplied for extraction, improper selection of extractants and the operation mode of the extraction cycle. To prevent such a process, it is important to study the extraction of the main components of productive solutions with different extractants. Studies on the extraction of metals from the productive solution of the Almaly deposit of composition, g/dm3 : Cu 0.235-0.262, Fe 17.97-21.55, SiO2 0.34-0.36 were carried out using reagents Acorga 5640 (10%), Acorga 5640 (5%) with CR60 additive and Lix 984N (10%). It was found that when using the first two, they led to the accumulation of iron and silica ions in the organic phase, and at Lix 984N (10%), the maximum transition of silica ions into the electrolyte, and iron into the raffinate. The accumulation of iron and silica ions in the organic phase is undesirable and may be the cause of crud formation.

Ligand Effect on Physicochemical Properties of Ionic Liquid.

In the solvent extraction process, the importance of an extractant (or ligand) and a diluent is inferred from their respective physicochemical properties. We have brought together all the recent results reported on the mixture of different extractants dissolved in a well-known ionic liquid diluent: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4 mim][NTf2 ]) in the form of a review and aimed to emphasize the role of ligand polarity and structure on the physicochemical properties of an ionic liquid (IL) diluent. Some of the most important properties such as dynamic viscosity (η), absolute density ( ), energy of activation (Ea ), coefficient of thermal expansion (α), phase separation time (PST), refractive index (n), etc., have been discussed meticulously in the paper. The effect of ligand structure on the aggregation behaviour of IL phase and the physicochemical properties of gamma irradiated solvent phases containing different ligands and their solution with IL phase also have been deliberated in detail.

A leaching, solvent extraction, stripping, precipitation and calcination process for the recovery of MoO3 and NiO from spent hydrofining catalysts

Effective recovery of elements from spent catalysts can not only avoid environmental hazards, but also alleviate the pressure of resource scarcity. This study proposes a hydrometallurgical process for the selective recovery of MoO3 and NiO from the spent hydrofining catalysts. First, valuable metals were leached with 0.5 mol/L H2SO4 and 4 wt% H2O2 at 25 °C for 20 min, resulting in the dissolution efficiencies of Mo, Ni and Al were 95.6%, 96.5% and 13.8%, respectively. Then, bis-(2-ethylhexy)phosphinic acid (P227) was chosen as the Mo extractant due to its higher separation factors of βMo/Al and βMo/Fe compared to di-2-ethylhexylphosphoric acid (P204) and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507). Extraction efficiency of 99.9% Mo was achieved at pH of 0.5 with 0.3 mol/L P227, whereas only 0.061 g/L Fe and <1 mg/L of other impurity elements were co-extracted. The complete stripping of Mo was realized with 0.4 mol/L (NH4)2CO3. Subsequently, a synergistic extraction system bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301) and trioctylphosphine oxide (TOPO) was employed to extract Ni, where the extraction efficiency was more than 99.9%. Around 99.9% of Ni was stripped with 9 mol/L HCl. With the addition of TOPO, not only the extraction ability of Ni was improved, but also realized the complete stripping of Ni. The two oxides MoO3 and NiO were prepared from the stripping solution. In addition, the extraction mechanism of Mo and Ni was studied. The total recovery efficiencies of Mo and Ni were 94.1% and 93.1%, with the purity of 99.9% and 99.0%, indicating that this innovative process can be utilized to recover MoO3 and NiO from the spent hydrofining catalysts.

Solvent Extraction for Separation of Indonesian Oil Sands.

Based on the examination of the basic properties, the solvent extraction process (SEP) was applied with high efficiency in the extraction of bitumen from Indonesian oil sands. To separate the oil sands, different organic solvents were first screened, and the extraction effects were analyzed to select a suitable solvent. Then, the effects of operating conditions on the extraction rate of bitumen were investigated. Finally, the compositions and structures of the bitumen obtained under suitable conditions were analyzed. The results showed that the Indonesian oil sands were oil-wet oil sands with a bitumen content of 24.93%, containing a large number of asphaltenes and resins with high polarity and complex structures. The separation performance was affected by different organic solvents and operating conditions. It was shown that the closer the structure and polarity of the selected solvent is to the solute, the better the extraction effect. The extraction rate of bitumen reached 18.55% when toluene was used as the extraction solvent under the operating conditions of V (solvent):m (oil sands) 3:1, temperature 40 °C, stirring velocity 300 r/min, time 30 min. The method could also be applied to the separation of other oil-wet oil sands. The compositions and structures of bitumen can guide the separation and comprehensive use of industrial oil sands.

Antibacterial and antibiofilm activity of extracts from sponge-associated bacterial endophytes

Sponges forms association with many bacteria that serve as sources of new bioactive compounds. The compounds are produced in response to environmental and nutritional conditions of the environment that enable them to protect their host from colonization. In this study, three sponge bacterial endophytes were isolated, identified, and subjected to solvent extraction processes. The identified bacteria are Bacillus amyloquifaciens, Bacillus paramycoides, and Enterobacter sp. The bacteria were cultured in two different fermentation media with varying nutritional composition for the extraction process. The extracts were evaluated for antibacterial and antibiofilm activity against microfouling bacteria and the chemical composition of each extract was analyzed via gas chromatography-mass spectrometry (GC-MS). The extract from the endophytes shows varying antibacterial and antibiofilm activity against the tested strains. Several compounds were detected from the extracts including some with known antibacterial/antibiofilm activity. The results showed variations in activity and secondary metabolite production between the extracts obtained under different nutritional composition of the media. In conclusion, this study indicated the role of nutrient composition in the activity and secondary metabolites production by bacteria associated with sponge Also, this study confirmed the role of sponge bacterial endophytes as producers of bioactive compounds with potential application as antifouling (AF) agents.

Removal of impurity Metals as Phosphates from Lithium-ion Battery leachates

Recovery of critical materials from end-of life (EOL) lithium-ion batteries (LIB) is gaining interest as demands for materials grows. Hydrometallurgical processes start with an intermediate product known as black mass which contains critical materials of interest (Co, Ni, Li, and graphite) as well as impurities such as Cu, Al, and Fe. These impurities are deleterious to downstream separation processes, as well as impact functionality of the final products. These impurities effectively compete with most solvent extraction (SX) and metal recovery processes to diminish the overall yields of the desired materials. In this work, a process flowsheet is presented where a previously reported electrochemical leaching (ECL) process is followed by selective precipitation using diammonium hydrogen phosphate (DAP) to remove Cu, Al, and Fe from LIB leachate solutions. The electrochemical leach process removes Cu and produces a pH-adjusted leachate, ca. pH 2, without requiring an extra Cu extraction step. The addition of the precipitant DAP to leachate by slightly adjusting the pH to 3–4 at 45 °C, precipitates 95–99% of Al and Fe as their phosphates and the leachate retains >95% of Co, Ni and Li. After the filtration of phosphate impurities, the solution is ready for further processing, such as SX. As an unexpected result from the leachate processing, 20–30% of the Ni and Co co-crystalize as the double salt after cooling to room temperature, which could provide a shorter route to their recovery.

Lipophilic Guanidine with Enhanced Stability for Use in Cesium Separation from Legacy High-Level Nuclear Waste

Guanidine functional groups are found in a variety of biologically active molecules and specialized molecules used in industrial applications but often suffer from instability because of their tendency to hydrolyze. Here, guanidines with differently structured alkyl groups were synthesized and their stabilities tested to determine if there is a relationship between the locus of branching in the alkyl groups attached to a guanidine and its hydrolytic stability under the hypothesis that increased steric hindrance to hydrolytic attack will increase stability. The guanidines examined in this work are pertinent to the next-generation caustic-side solvent extraction (NG-CSSX) process, which was developed for the removal of radioactive cesium from highly radioactive and complex alkaline solutions. In the NG-CSSX process, a lipophilic alkylguanidine solvent component is highly important to maintain the effectiveness of the Cs+ stripping of the loaded organic solvent putatively by sequestering extractable anions. Currently used for this purpose, N,N′,N″-tri(3,7-dimethyloctyl)guanidine (TiDG) succumbs to slow hydrolysis under process conditions. Guided by quantum chemical calculations, two new guanidines with large, sterically bulky alkyl substituents have been designed, synthesized, and tested. More sterically hindering alkyl groups were found to increase the stability of guanidines, particularly for the guanidine with branching closest to the guanidine N atom: N,N′-dicyclohexyl-N″-(10-nonadecyl)guanidine (DCNDG). DCNDG was found to have a stability toward hydrolysis 8 to 44 times greater than that of TiDG under different simulated NG-CSSX process conditions, making it one of the most hydrolysis-resistant guanidine molecules reported to date.

Rapid LC-MS/MS quantification of Organophosphate non-specific metabolites in hair using alkaline extraction approach

Assessing human exposure to commonly used, highly toxic, but non-persistent organophosphates (OPs) is challenging because these toxicants are readily biotransformed into dialkyl phosphates (DAPs) and other metabolites. Growing hair accumulates toxicants and their metabolites, which makes hair a valuable non-invasively sampled matrix that can be used to retrospectively examine chemical exposure. However, the efficient quantification of hydrophilic DAP compounds in hair is challenging due to complex hair matrix effects. To improve upon existing methods, we first examined the acid dissociation constants (pKa) of DAPs and amino acids (major components in hair) and identified the best pH conditions for minimizing matrix effects. We hypothesized that under basic pH conditions DAPs and amino acids would be negatively charged and have weak interactions favorable to DAP dissociation from the matrix. To test this, we compared the efficiency of various pH conditions of suitable solvents to extract six DAPs from hair samples, and we quantified these DAPs using liquid chromatography-tandem mass spectroscopy (LC-MS/MS). As expected, a basic extraction (methanol with 2% NH4OH) approach had the highest extraction efficiency and yielded satisfactory recoveries for all six DAPs (72%-152%) without matrix effects. Additionally, the alkaline extract can be directly injected into the LC-MS/MS. This relatively rapid and simple procedure allowed us to process up to 90 samples per week with reproducible results. To our knowledge, this is the first method to quantify all six DAPs simultaneously in hair using LC-MS/MS with electrospray ionization (ESI) in negative ion mode. Finally, we demonstrated the feasibility of measuring DAP levels in hair samples from patients affected with amyotrophic lateral sclerosis (ALS), a neurodegenerative disease potentially linked to OP exposure. Due to our optimized solvent extraction process, the method we have developed is compatible with the rapidity and sensitivity needed for hair analysis applied to population biomonitoring.

Recovery of Li2CO3 and FePO4 from spent LiFePO4 by coupling technics of isomorphic substitution leaching and solvent extraction

Efficient and low-cost recycling of spent lithium iron phosphate (LiFePO 4 , LFP) batteries has become an inevitable trend. In this study, an integrated closed-loop recycling strategy including isomorphic substitution leaching and solvent extraction process for spent LFP was proposed. An inexpensive FeCl 3 was used as leaching agent to directly substitute Fe 2+ from LFP. 99% of Li can be rapidly leached in just 30 min, accompanied by 98% of FePO 4 precipitated in lixivium. The Tri-n-butyl phosphate (TBP)-sulfonated kerosene (SK) system was applied to extract Li from lixivium through a twelve-stage countercurrent process containing synchronous extraction and stepwise stripping of Li + and Fe 3+ . 80.81% of Li can be selectively enriched in stripping liquor containing 3.059 mol·L -1 of Li + under optimal conditions. And the Fe stripping liquor was recovered for LFP re-leaching, of which, Fe 2+ was oxidized to Fe 3+ by appropriate H 2 O 2 . Raffinate and lixivium were concentrated and entered into extraction process to accomplished close-loop recycling process. Overall, the results suggest that more than 99% of Li was recovered. FeCl 3 holding in solution was directly regenerated without any pollutant emission. The sustainable mothed would be an alternative candidate for total element recycling of spent LFP batteries with industrial potential.

Current Agronomic Practices, Harvest &amp; Post-Harvest Processing of Soybeans (Glycine max)—A Review

Globally, soybeans are grown to meet the needs for animal and human nutrition, oil extraction, and use in multiple industrial applications. Decades of soybean research, innovative farming methods, and the use of higher yielding resistant seed varieties have led to increased crop yields. Globally, soybean producers have utilized enhanced processing methods to produce nutritious high-quality meal and extracted oil for use in animal feed and within the food industry. Soybeans contain highly digestible proteins and are processed using various mechanical and chemical techniques to produce high quality animal feed ingredients. Defatted soybean meal (DSM) is usually prepared by the solvent extraction process of soybeans, whereby almost all oil content is removed. When oil is not extracted, full-fat soybean meal (FFSBM) is created. This form provides an excellent source of dietary energy by retaining the lipid component and is very useful in animal feeds by reducing the need for adding exogeneous lipids. However, some anti-nutritional factors (ANF) are present in FFSBM if not properly heat treated before inclusion in the finished feed. These ANF adversely affect the internal organ function and overall growth performance of the animal. Among these ANF, protease inhibitors are most important, but can be readily destroyed with optimal thermal processing. However, if the process protocols are not followed precisely, excessive heat treatment may occur, resulting in both reduced protein quality and amino acid bioavailability in the meal. Conversely, insufficient heat treatment may result in the retention of some ANF in the meal. Thermally resistant ANF can be greatly reduced in the bean and meal when dietary enzyme supplementation is included in the finished feed. This approach is cost-effective and most commonly utilized commercially. After processing, the soybean meal quality is often measured using in vitro methods performed at commercial analytical laboratories to assess the nitrogen solubility index (NSI), protein dispersibility index (PDI), urease activity (UA), and protein solubility in potassium hydroxide. Once properly processed, FFSBM or DSM can be utilized optimally in the diets of poultry and aquaculture to enhance the economic viability, animal nutrition, production performance, and the quality and nutritional value of the meat and/or eggs produced.

Polyphenol extraction from olive leaves to show Chemical Engineering students the importance of revaluating residues while improving their hands-on experience

The aim of this work was to try to implement a new laboratory class for Chemical Engineering students in which they could analyze how it is possible to revalue some organic residues. Concretely, the objective was to show them how to revalue olive leaves by extracting their polyphenols, since these leaves, being an abundant organic waste in Spain, were well-known by the students to whom this study was addressed. With the aim of improving student understanding of the basic Chemical Engineering concepts, two extraction techniques (solvent extraction process and ultrasound-assisted extraction) as well as their combination were investigated during the class. In addition, the effect that different pre-treatments had on polyphenol extraction efficiency was also studied to show students how important research is before fine-tuning an industrial process. To do this, students were divided into working groups to carry out polyphenol extraction under different experimental conditions. Ultimately, student groups compared and discussed the efficiency of the different employed extraction techniques. Likewise, students were surveyed to evaluate the suitability and training-usefulness of the proposed class. Obtained assignments revealed that it could be an interesting option to improve students’ hands-on experience while strengthening some theoretical concepts explained in the degree lectures.

Predictive methods for density and refractive index of naphthenic lubricating oils during solvent extraction process

Lubricating oils are usually produced by solvent extraction to separate aromatics in order to achieve the desired specifications and better quality products. Among the different properties of lubricating oils, density and refractive index are some of the most important properties which can both be used for petroleum fluid characterization. Predictions of density and refractive index for naphthenic oils during solvent extraction by DMSO obtained by the pseudo-component approach and the quadratic correlation were both examined. The pseudo-component approach is a method to predict density and refractive index from composition while the latter merely relates density to refractive index. Results indicated that the predictions yielded by the pseudo-component method were in good agreement with experimental data for naphthenic oils. And the use of a function of refractive index (FRI20) as a pseudo-component property remarkably improved n20 predictions for the naphthenic mixtures. However, the density and refractive index predictions obtained by the quadratic correlation exhibited significantly higher deviations for naphthenic oils than those for paraffinic oils. Thus a new modified correlation of the same functional form was proposed for naphthenic oils. The modification significantly improved predictions for naphthenic oils, which presented similar accuracy as the pseudo-component approach. And the previous correlation was still used for paraffinic oils.Additionally, effect of temperature on density and refractive index of naphthenic oils was examined. Results showed that the modified quadratic correlation was accurate for describing the relationship between density and refractive index of naphthenic oils at 20–90 °C. The temperature dependence of density and refractive index for the raffinates and the extracts could be accurately described by the thermal coefficients for saturates and aromatics, respectively. Regarding the refractive index variation of the extracts with temperature, the empirical equation was proved to be a better option compared with the method using the thermal coefficient for aromatics.

Получение нафтеновых масел в процессе селективной очистки нафтеноароматического сырья

The article shows the possibility of producing medium-refined naphthenic oils from naphthenic-aromatic crude using a solvent extraction process. A comparative characteristic of the obtained raffinates with commercial naphthenicoils has been carried out. Potential directions for the use of the obtained raffinates of solvent extraction, analogues of naphthenic oils, are determined, taking into account the volumes of their consumption in Russia.The economic efficiency and expediency of organizing the production of naphthenic oils from naphthenic-aromatic crude using the solvent extraction process is shown.