Solvent Extraction Technology Research Articles

Extractive metals from metallic powders recovered from waste printed circuit boards

Leaching behaviours of metallic powders were investigated using electrically generated chlorine at the anode chamber containing sulphuric acid solution, NaCl and CuSO4. Various parameters, which included the solid/liquid ratio, current density, concentration of NaCl, CuSO4, and H2SO4, leaching temperature, particle size, and stirring speed, were studied to understand the mechanism of leaching metallic powders. The capability of dissolved metallic powders increased with the increase in all parameters except the solid/liquid ratio. Leaching metallic powders were transport-controlled with a low activation energy of 14·7 kJ mol−1. The dissolved copper could be transferred from the anodic chamber to the middle chamber by solvent extraction technology. In the electric field, copper ions are transferred from the middle chamber to the cathodic chamber through a cation exchange membrane (CEM) and electrodeposited to form copper foils. The tensile strength and elongation percentage of 65 μm-thick copper foils were 276 Mpa and 10·66%, respectively. The utilisation of metallic powders recovered from waste PCBs (WPCBs) could produce high-performance copper foil.On a examiné le comportement de lixiviation de poudres métalliques en utilisant du chlore engendré par électricité dans la chambre de l’anode contenant une solution d’acide sulfurique, du NaCl et du CuSO4. On a étudié une variété de paramètres, incluant le rapport solide à liquide, la densité de courant, la concentration de NaCl, de CuSO4 et d’H2SO4, la température de lixiviation, la taille de particule et la vitesse d’agitation, afin de comprendre le mécanisme de lixiviation des poudres métalliques. La capacité des poudres métalliques dissoutes augmentait avec l’augmentation de tous les paramètres, sauf le rapport solide à liquide. Les poudres métalliques de lixiviation étaient contrôlées par le transport, avec une faible énergie d’activation de 14·7 kJ/mol. On pouvait transférer le cuivre dissous de la chambre anodique à la chambre du milieu au moyen de la technologie d’extraction par solvant. Dans un champ électrique, les ions de cuivre étaient transférés de la chambre du milieu à la chambre cathodique par une membrane d’échange de cation et étaient déposés par galvanoplastie pour former des feuilles de cuivre. La résistance à la traction et le pourcent d’élongation de feuilles de cuivre de 65 μm d’épaisseur étaient respectivement de 276 MPa et de 10·66%. Les poudres métalliques récupérées de cartes de circuit imprimé de rebut pourraient produire une feuille de cuivre à haute performance.

Conceptual Process Design and Economic Analysis of a Process Based on Liquid–Liquid Extraction for the Recovery of Glycols from Aqueous Streams

The recovery of monoethylene glycol (MEG) and 1,2-propylene glycol (PG) from aqueous streams via liquid–liquid extraction (LLE) using a tailor-made ionic liquid [TOA MNaph] is evaluated as an alternative technology to conventional triple effect evaporation of water. In this paper, the conceptual process designs for the purification of aqueous MEG from petrochemical feedstock and the recovery of PG from fermentation broths using both separation technologies are presented. The results show that LLE technology offers high energy savings, around 94% for MEG production (from petrochemical feedstock) and 54% for the PG (from fermentation broth) process compared to triple effect distillation. The economic evaluation shows that at current crude oil prices (€70–95/barrel), LLE for MEG production is not a suitable option. This holds particularly for the biological production of MEG. In the case of PG, even though the capital investment is much higher for the solvent extraction technology, the extraction process is beneficial in terms of total annual costs for the recovery of PG (plant capacity < 100 kton/year and glycol feed concentrations < 10 wt %), which is strongly dependent on the glycol distribution coefficient and selectivity of PG.

Preparation of Ultrafine Copper Oxide Using Metal Powders Recovered from Waste Printed Circuit Boards

AbstractWaste printed circuit boards (WPCBs) have an inherent value because of nonferrous metal copper and noble metals. From the viewpoint of resource recycling and environmental protection, it is significant to recover metal materials from WPCBs. In this study, metal powders recovered from WPCBs were used to prepare ultrafine copper oxide powders using a microemulsion reaction. First, WPCBs were pretreated to obtain the metal powders with a copper content of 86.1% using a mechanical physical method. The leaching of the metal powders was carried out in a sulfuric acid solution by adding chloride and copper ions under aeration condition. By a solvent-extraction technology, copper ions in the leaching solution were extracted by N902 extractant and the raffinate was used to leach metal powders again. The loaded organic phase (N902 extractant) was stripped by an oxalic acid solution to form a microemulsion system. Ultrafine copper oxalate precipitations were produced in the microemulsion interfaces, and then...

Deacidification of Soybean Oil Combining Solvent Extraction and Membrane Technology

The aim of this work was to study the removal of free fatty acids (FFAs) from soybean oil, combining solvent extraction (liquid-liquid) for the separation of FFAs from the oil and membrane technology to recover the solvent through nanofiltration (NF). Degummed soybean oil containing 1.05 ± 0.10% w/w FFAs was deacidified by extraction with ethanol. Results obtained in the experiences of FFAs extraction from oil show that the optimal operating conditions are the following: 1.8 : 1 w : w ethanol/oil ratio, 30 minutes extraction time and high speed of agitation and 30 minutes repose time after extraction at ambient temperature. As a result of these operations two phases are obtained: deacidified oil phase and ethanol phase (containing the FFAs). The oil from the first extraction is subjected to a second extraction under the same conditions, reducing the FFA concentration in oil to 0.09%. Solvent recovery from the ethanol phase is performed using nanofiltration technology with a commercially available polymeric NF membrane (NF-99-HF, Alfa Laval). From the analysis of the results we can conclude that the optimal operating conditions are pressure of 20 bar and temperature of 35°C, allowing better separation performance: permeate flux of 28.3 L/m2·h and FFA retention of 70%.

청정 에너지원 하이퍼 콜의 제조 기술 동향

우리는 지속가능성을 우선시하는 메카트렌드 시대에 살면서 고유가 영향으로 고품위급 석탄에 비해 상대적으로 자원이 풍부하면서 가격이 저렴한 저품위 석탄 자원의 에너지 청정화 기술(예: 유효 성분추출 기술, 회 성분 제거 기술) 개발이 필요하게 되었다. 이를 실현하기 위해 유효 성분 추출 접근법에 바탕을 둔 청정 석탄인 하이퍼 콜(HC: hyper coal)의 제조 기술에 대한 니즈가 몇몇 국가들을 중심으로 점차로 확산되고 있다. 이러한 이유는 HC 활용으로 온실가스 배출량 감축, 에너지 효율 제고 등과 같은 효과를 얻어 지속가능한 사회를 실현할 수 있기 때문이다. 이러한 니즈를 바탕으로 여기서는 HC에 중점을 두면서 HC 제조 기술과 관련하여 국내외 HC의 연구 개발 동향을 소개하고자 한다. 더 구체적으로 말해, HC를 제조하는 방법으로 용매 추출 기술 가운데 옴 가열(OH) 추출 방법 및 마이크로웨이브 조사(MI) 추출 방법 등의 개발 현황을 문헌 조사를 통해 살펴보고자 한다. 이들 기술의 검토 결과에 따르면, HC 제조에서 MI 추출 방법의 장점을 살린 용매 추출 공정 기술이 매우 경제적이고 대규모 제조에 적합한 것으로 파악되었다. 향후에는 이 추출법을 포함하는 파일럿 공정, 더 나아가 상업용 제조 공정 개발이 필요하다. Currently, there are the technologically urgent needs of fabricating the hyper coal (HC) based on the approach to extracting mainly effective organics from low rank coals (LRCs), because some industrial countries pursue global sustainability dealing with hot issues such as local energy supply security as well as global warming. In this study, as of the fabrication of clean HCs via LRCs upgrading, we comprehensively review the R&D status of two solvent extraction technologies, namely, Ohm heating (OH) and microwave irradiation (MI) extraction processes on the basis of the performance indicator such as a HC extraction yield.

Utilisation Potential of Feijoa Fruit Wastes as Ingredients for Functional Foods

Feijoa fruits have high antioxidant activity as they contain significant concentrations of polyphenols (PPs), carotenoids and vitamins. This study evaluates the colour, pH, total soluble solids (TSS), pectin fibre content, total extractable PP content (TEPC) and total antioxidant activity of the extracts generated from the fruit wastes (primarily skin and some flesh) remaining after feijoa flesh consumption. Extractions were conducted at room temperature and 50 °C using accelerated solvent extraction technology and different extraction media [water, acidified water (containing citric acid, pH 3.5), and 30, 50 and 80 % (v/v) aqueous ethanol solutions]. Results show that the composition and properties of the extracts depend on the extraction media and, to a lesser extent, on the extraction temperature. The 80 % ethanolic extract was bright green in colour. The water and acidified water extracts showed more browning than the ethanolic extracts, suggesting possible detrimental sensory impacts for food applications. The TSS decreased in the order of 80, 50 and 30 % ethanolic and water extracts. The 50 % ethanolic extract had the highest TEPC and antioxidant activity at both extraction temperatures, which was supported by high performance liquid chromatography analyses. The extracts produced with solutions containing less ethanol, especially water extracts, had higher pectin contents. The UA content of the extract produced using water alone was the highest (5.56 % as GalA) at 20 °C, whilst that produced using 30 % ethanol solution was the highest (3.90 % as GalA) at 50 °C. Higher extraction temperature (50 °C) resulted in lower pectin contents. These results demonstrate the potential of feijoa waste extracts, especially 50 and 80 % ethanolic extracts, as ingredients for functional food applications.

Membrane contactors (NDSX and EPT): an innovative alternative for the treatment of effluents containing metallic pollutants

This work presents an overview of membrane-based solvent extraction technologies using membrane contactors as an innovative alternative for the remediation of effluents containing metallic pollutants. The discussion is focused on the description of Non-Dispersive Solvent Extraction (NDSX) and Emulsion Pertraction Technologies (EPTs). Three case studies are reported to demonstrate the viability of NDSX and EPT for the removal and recovery of metallic pollutants present in aqueous streams:

Comparative Simulation of the Purification of Wet Phosphoric Acid by Tbp, Mibk and a Mixture (MIBK+TBP)

Liquid-liquid solvent extraction technology is used in several industrial processes such as petrochemical processing, pharmaceutical production, food and hydrometallurgy. It is successfully applied for the purification of Wet Phosphoric Acid (WPA) with fairly good purification performances. The purification process is basically carried out in three steps: extraction, washing and recovery, each of these steps is a liquid-liquid extraction operation. The aim was to develop a computer code that helps predicting the overall performance of the purification process for a given set of operating conditions. The adopted approach is based on determining the necessary theoretical stages for each step in the purification process using a numerical technique. Some simulation results for the WPA purification process with Tri-Butyl Phosphate (TBP) at 45°C, Methyl Isobutyl Ketone (MIBK) at 25°C and a mixture (MIBK+TBP) at 30°C are presented.

Recovery of Copper(II) and Nickel(II) from Plating Wastewater by Solvent Extraction

The solvent extraction technology was applied to recover Cu 2+ and Ni 2+ from plating wastewater. Lix984N was chosen as the extractant due to its good extraction performance. The influence parameters were examined. The results show that the separation of Cu 2+ and Ni 2+ from sulphate medium can be realized by adjusting pH value with the help of Lix984N. For extracting Cu 2+ and Ni 2+, the optimal pH values are 4 and 10.5, and the maximal extraction percentages are 92.9% and 93.0%, respectively. With recovered Cu 2+ and Ni 2+ stripped in 170 g·L −1 and 200 g·L −1 H 2SO 4 medium, the stripping percentages of Cu 2+ and Ni 2+ are 92.9% and 93.0%, respectively. This method is simple and can be used to recover Cu 2+ and Ni 2+ from plating wastewater. And a flow sheet for separation of Cu 2+ and Ni 2+ is presented.

ANTIOXIDANTS FROM WINEMAKING WASTES: A STUDY ON EXTRACTION PARAMETERS USING RESPONSE SURFACE METHODOLOGY

Winemaking by-products present a high environmental impact due to their considerably high biochemical and chemical oxygen demands. This study is focused on the optimization of the traditional solvent extraction technology of phenols from Pinot Noir grape skins (Vitis vinifera). To such a purpose, the combined effects of the extraction time (9, 19 and 29 h) and the solid-liquid ratio (0.10, 0.20 and 0.30 gDW/mL), were investigated by a 32 full factorial design combined with response surface methodology; total polyphenols, flavonoids and trans-resveratrol extraction yields were used as response variables. Results demonstrated that Pinot Noir skins had high levels of both total polyphenols (3.22 mgGAE/gDW) and flavonoids (1.01 mgCE/gDW), being the optimum extraction time 19 h approximately. t-resveratrol was found in a considerable amount (2.24 mg/100 gDW), while the main phenolic compounds analyzed with Reverse Phase-High Performance Liquid Chromatography were gallic acid, catechin and quercetin. A significant linear correlation was found between polyphenols concentration and their antiradical power. PRACTICAL APPLICATIONS Winery by-products (grape marc) are a possible font of antioxidants and their extracts can represent a significant economic and social benefit. The research of the efficient methods for phenolics compound extraction is one of great interest. Collected experimental data could be used in further studies as a comparison with those of other innovative technologies, such as supercritical fluid, ultrasound and/or microwave-assisted extraction.

Separation and purification of scandium by solvent extraction and related technologies: a review

AbstractThe technologies of solvent extraction, ion exchange, and liquid membrane for the separation and purification of scandium are reviewed. Acidic and neutral organo‐phosphorus extractants are most widely used in practice, with high extraction efficiencies. Their disadvantages originate from the high stripping acidity required for the former and the poor selectivity for the latter. Carboxylic acids, amines, and acidic β‐diketone have also been widely used to extract scandium from solutions with low acidities. Mixed extractants or synergistic systems for the solvent extraction of scandium have been developed. Extraction efficiencies are influenced by extraction conditions such as aqueous matrixes and acidities, types of diluents and A/O ratios. Scandium(III) extractions are interfered with by commonly associated elements such as iron(III), zirconium(IV), titanium(IV), thorium(IV), yttrium(III) and lanthanides(III). The advantages and disadvantages of applications of ion exchange and liquid membrane technologies for scandium recovery are reviewed and compared with solvent extraction. Copyright © 2011 Society of Chemical Industry

Synthesis of sulphonated microcapsules of P(St–DVB) containing di(2-ethylhexyl)phosphoric acid

A new sulfonated material from styrene–divinylbenzene copolymer, P(St–DVB), containing di(2-ethylhexyl)phosphoric acid (DEHPA) that combines the advantages and capabilities of the ion exchange and the solvent extraction technologies has been developed. Microcapsules with a DEHPA content of 34.86 wt.%, an average particle size of 340.83 μm and an equivalent thickness shell of 22.4 μm were prepared by suspension-like polymerization technique and further sulfonated. The influence of the chemical nature and properties of the suspending agent on the microcapsules characteristics were studied. The polluting potential of the wastewater generated in the encapsulation process with the different suspending agents was also evaluated. Arabic gum:PVA showed to be the best combination of suspending agent for the process. The incorporation of sulfonic groups to the polymeric network turn the hydrophobic nature of the particle into another with hydrophilic character. The increase of the sulfonation time from 10 to 30 min promoted the cracking of the microcapsules (from 24.49 to 75.36 wt.%). A total ion exchange capacity of 3.56 meq g −1 was achieved. The large ion exchange rate and capacity observed confirm that the sulfonation of the shell makes easier the mobility of the metallic ions from the liquid phase to the extractant agent phase through the shell. It was also observed that the presence of DEHPA into the microcapsules makes them more selective than a conventional ion exchange material.

Developments in oil extraction from microalgae

Microalgae are a diverse group of organisms with significant potential for industrial applications: as feedstock in aquaculture as well as in the production of valuable bioproducts such as lipids, carotenoids and enzymes. Lately, developments in molecular biology have improved production yields of algae bioproducts, thus increasing their industrial relevance. Additionally, variations in bioprocessing factors (i.e. temperature, pH, light, carbon source, salinity, nutrients, etc.) have been used to enhance both biomass and specific bioproducts' productivities. Particularly, microalgae have increasingly gained research interest as a source of specialty lipids such as arachidonic, eicosapentaenoic and docosahexaenoic acids, which are often reported in literature to provide several health benefits. Moreover, there has been a recent resurgence in interest in microalgae as an oil producer for biofuel applications. Significant advances have also been made in upstream processing to generate cellular biomass and oil. However, extracting and purifying oil from algae continues to prove a significant challenge in producing both microalgae bioproducts and biofuel, as microbial oil extraction is relatively energy-intensive and costly. Thus, developing inexpensive and robust oil extraction and purification processes is a major challenge facing both the microalgae to bioproduct, and biofuel industries. This paper presents an overview, based on the last 10 years, of advances made in technologies for extracting and purifying microalgae oil. We compared solvent extraction technologies with extraction alternatives such as mechanical milling and pressing, enzymatic and supercritical fluid extraction. We also reviewed recent advances based on molecular engineering of microbes to aid oil extraction. Downstream processing for the potential commercial production of microalgae oil not only must consider economic costs, but should also consider minimizing environmental impacts in order to attain sustainable production processes.

Surfactant assisted ethanol extraction of dioscin

In order to achieve the cleaner production of diosgenin and more importantly to reduce the production cost of diosgenin, the ultrasonic assisted solvent extraction technology is adopted and different types of surfactants are introduced into the study of the extraction of dioscin. Moreover, dioscin is used as the evaluation indicator to study the effects that different extraction conditions may have on extraction efficiency. It is discovered that when the volume fraction of ethanol is 30 v/v, ultrasonic frequency reaches 25.8 KHz, solid-liquid ratio (Dioscorea zingiberensis:ethanol) is 1:10, the dosage of SDS is 2 × 7.363 × 10-3mol/L and the extraction duration is 40 min; however, the extraction rate of the dioscin is the highest. This technique can greatly decrease the volume fraction of the ethanol in the extraction of dioscin, so that the production cost of diosgenin is greatly reduced. Key words: Dioscorea zingiberensis, diosgeninr, ultrosonic waves, sodium dodecyl sulfate (SDS).

Functionalization of microcapsules for the removal of heavy metal ions

BACKGROUND: Solvent extraction and ion exchange technologies have been widely used for the recovery or removal of heavy metals from aqueous phases. However, different problems have been encountered on applying these techniques. Although the extractants are highly selective, this technique requires a high level of mechanical agitation to improve the kinetics of the process, a requirement that promotes leakage of the extractant from the aqueous/organic interface to the aqueous phase during separation of the two phases. On the other hand, ion exchangers can easily be regenerated but gel form resins have low selectivity and those with high selectivity (chelating resins) have low diffusion coefficients, a characteristic that leads to low mass transfer rates. An interesting alternative to overcome these limitations is the microencapsulation of extractants within a functionalized polymeric shell. This new type of material would be expected to combine the advantages of the aforementioned methods and improve selective removal of heavy metals from an aqueous phase. RESULTS: Sulfonation of microcapsules indicated that the use of an ethylene glycol dimethacrylate (EGDMA) copolymer enhances the chemical and mechanical properties of the microcapsules. It was found that the recipe used to produce microencapsulated phase change materials (PCM) was also useful to prepare microcapsules with di(2-ethylhexyl)phosphoric acid (DEHPA) as a core material. The synthesized material had a spherical and smooth shape and a DEHPA content of 28.15 wt%. Finally, the ion exchange capacity of the sulfonated material containing DEHPA (3.02 meq g−1) was higher than that obtained without this additive (2.54 meq g−1). High selectivity for copper uptake was also achieved. CONCLUSIONS: Microcapsules containing extractants can be manufactured by the same approach used to produce microcapsules containing PCMs. In addition, particles with improved chemical and mechanical resistance to sulfonation can be synthesized using EGDMA as a crosslinker. Ion exchange studies showed that the presence of DEHPA enhances the ion exchange capacity and selectivity of the microcapsules. Thus this material is a promising alternative for the separation of heavy metal ions. Copyright © 2010 Society of Chemical Industry

Phosphate ore processing for phosphoric acid production: classical and novel technology

Phosphoric acid (H3PO4, PA) is an industrial acid, produced from two main types of phosphate rock: sedimentary and igneous. In the classical wet process, wet process PA is produced by a reaction between the ore and sulphuric acid, forming 30% solids thick slurry, in three stages: acidulation, filtration and concentration to produce a 50%P2O5 acid. In a novel process, the phosphate ore is treated with HCl with the formation of PA and CaCl2; the PA is separated by a solvent extraction technology, obtaining a highly concentrated, food grade PA and recovering the organic solvent. The PA industry has a high level of corrosion risk; therefore, special corrosion resistant materials (metallic and plastic) are applied according to the chemical, mechanical and thermal conditions of the process. Cases of PA production of different qualities and concentrations, by diverse methods in Mexico and Israel, are presented.

Chemical and bioassay monitoring of PCB-contaminated soil remediation using solvent extraction technology

Illegal dumping of polychlorinated biphenyl (PCB) capacitors was discovered in Kobe, Japan, in 2001, leaving about 68 m(3) (92 tons) of soil contaminated with approximately 6.6 kg of PCBs. Solvent extraction technology carried out in 2002-2003 using isopropyl alcohol remedied the affected soil at the site. Forty-seven batch treatments were conducted during full-scale treatment. On average, 8.4 extraction cycles per batch were needed to achieve the clean-up goal for PCBs (i.e., the Japanese environmental quality standard for soil). Analytical results showed that the average PCB concentration (88 microg g(-1)-dry soil) in untreated soil samples of all the batches was decreased to 1.2 microg g(-1)-dry soil in treated soil samples, yielding a removal efficiency of 98.6%. Dioxin responsive-chemical activated luciferase gene expression assay (DR-CALUX) and enzyme-linked immunosorbent assay (ELISA) adopting a monoclonal antibody against 2,3',4,4',5-pentachlorobiphenyl (PCB #118) were used to rapidly screen soil samples before and after solvent extraction. The DR-CALUX and ELISA results were in good agreement with World Health Organization toxicity equivalent values and analytically determined PCB concentrations, respectively. Regular monitoring during the treatment period confirmed that the applied technology met Japanese environmental and control regulations concerning treatment and disposal of contaminated soils and treatment residues. After full-scale treatment, the amount of PCBs recovered from the solvent purification system approximated the estimated amount of PCBs spilled.

Membrane processes for the efficient recovery of anionic pollutants

The development of new “zero discharge” technologies which also permit the recovery of pollutant anions from industrial waste waters is a way of minimizing the cost of the processes and the impact on the environment. The kinetic behaviour of the removal and recovery of two different anionic pollutants is reported using membrane-based solvent extraction technologies: (1) recovery of hexavalent chromium anions contained in groundwaters by means of emulsion pertraction (EPT) and (2) recovery of zinc chlorocomplexes from spent pickling solutions by means of non dispersive solvent extraction (NDSX). Kinetic experiments were performed in order to study the influence of different variables on the separation kinetics, i.e., the NaOH concentration in the stripping phase in the case of chromium and the initial metal concentration in the aqueous feed solution in the case of zinc recovery.

Interfacial Phenomena in Solvent Extraction and Its Influence on Process Performance

Solvent extraction is now finding applications in a broader range of fields than the past. Many of these applications require process equipment with shorter contact times, and in some cases to the point where the traditional equilibrium stage approach is not a good model for predicting performance. In addition, feed streams are becoming lower in concentration of the solute. This means greater feed to solvent flow ratios are being used and so loss of organics as entrainment in the feed is more of a concern both economically and environmentally. These trends mean that a greater emphasis is being placed on the kinetics of extraction and stripping in models to predict performance and on formation and coalescence of drops to control entrainment. This paper reviews recent advances in the tools for investigating kinetics and coalescence in solvent extraction processes and some of the insights that are being uncovered in these fundamental processes in solvent extraction technology.

Solvent Extraction Developments in Southern Africa

The largest solvent-extraction plant in the world at the time, the Nchanga Copper Operation, was in Zambia. The first commercial process using solvent extraction for the refining of the platinum-group metals was in South Africa. More recently, the Southern African region has seen the implementation of solvent extraction for other base metals, precious metals, and specialty metals. These include the world firsts of primary production of zinc at Skorpion Zinc in Namibia and the large-scale refining of gold by Harmony Gold in South Africa. Several other flowsheets that use solvent-extraction technology are currently under commissioning, development, or feasibility study for implementation in this part of the world, including those for the recovery of copper, cobalt, nickel, tantalum, and niobium.