Conventional Extractors Research Articles

Modernization of operating chicory factories using continuous pulsating extractors

Chicory roots are a valuable source of inulin and other healthy nutrients. The most common direction of their industrial processing is instant chicory powder production. Extraction is the main process in the production. Conventional extraction methods, which include maceration, percolation and extraction in a screw extractor, have a number of significant drawbacks, including high capital and operating costs, low quality of the resulting extract, complexity in repairing equipment, short overhaul life, etc. The purpose of the present study was to assess the technical feasibility of increasing extraction process efficiency through using continuous pulsating extractors (CPE) developed by the Ingehim company, in which a non-stationary, countercurrent mode of interaction of raw materials with the extractant is incorporated. Testing of engineering solutions implemented in CPE was carried out at a pilot pulsating unit (PPU). For extraction, roasted and crushed (5–20 mm) chicory roots from one of the operating chicory factories were used. The ratio chicory : water during extraction was 1 : 4.5, which is 1.5–2.5 times lower than in conventional extractors. A lower extraction temperature (up to 85°C) combined with a shorter extraction time (up to 1 hour) may help retain more inulin and other nutrients as compared to conventional methods. The results of the study at the PPU under these conditions confirmed the high yield of water-soluble solids (up to 98%) without additional grinding. A scheme for the modernization of a chicory factory equipped with the most common percolation extraction equipment having a feed capacity of 400 kg/h is proposed through using CPE. 3D images of the proposed modernization are shown. A comparative assessment of energy consumption for extraction using different methods is given. The results of the study indicate the capability and high efficiency of CPE for extracting chicory, which is confirmed by a decrease of up to 3.6 times in the total specific energy consumption for obtaining 1 kg of instant chicory powder compared to conventional extractors. Low capital and operating costs determine the prospects for using CPE for the modernization of existing chicory factories or the creation of new energy-efficient factories.

Solvent extraction of Ce(III) and Pr(III) with P507 using SiC foam as a static mixer

Extraction reactor is a major research area of interest within the field of rare earths extraction and separation. SiC foam offers excellent material characteristics as well as three-dimensional (3-D) reticulated structure; however, very little research has been carried out on its application in extraction reactor so far. In this work, a static mixer reactor based on SiC foam was designed and demonstrated to extract and separate Ce(III) and Pr(III) from nitric acid media by using 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) as extractant. The structure–performance relationship between SiC foam and extraction performance was studied by experiment combined with computational fluid dynamics (CFD) simulation. The experiment data are in good agreement with the simulation results. Contrast experiment by using a Kenics mixer was carried out, and SiC foam shows better extraction and mass transfer performance. Using the optimal structural SiC foam (pore size D = 2.3 mm, open porosity ε = 85%, foam length L = 80 mm), high extraction efficiency η (Pr(III): 94.6%, Ce(III): 88.5%) and separation factor β (2.27) between Ce(III) and Pr(III) is achieved at a high total throughput of 200 mL/min. Besides, overall volumetric mass transfer coefficient KLa of Pr(III) and Ce(III) are 0.519 and 0.378 s−1 at the residence time τ of 3.6 s, respectively, which reach the high level of microchannel reactors and are better than conventional extractors and other static mixers. SiC foam is found to be applicable as a static mixer for efficient and high-throughput extraction and separation of rare earths.

Intensified solvent extraction and separation of cobalt from Ni-rich leaching solution in impinging stream-rotating packed bed contactor

ABSTRACT This work describes the separation of Ni and Co from a real feed solution in chloride media with high Ni content. The extractant used was P507 (2-ethylhexyl phosphoric acid-2-ethylhexyl ester) in a laboratory scale Impinging Stream–Rotating Packed Bed (IS-RPB) contactor. Key variables including feed solution pH, extractant concentration, saponification degree, high gravity level and total volumetric flow rate of fluids amongst other variables were examined. A McCabe–Thiele diagram of the extraction stage predicted that at a total volumetric flow rate of 90 L/h, feed solution pH of 5, saponified P507 concentration of 25% and high gravity of 83, almost 99% of cobalt, would be extracted within three stages. With regard to the scrubbing results, the co-extracted nickel was scrubbed efficiently from the loaded organic solution using a mixture of 0.02 M CoCl2 and 0.5 M hydrochloric acid solution, The purified Co solution was achieved after stripping the loaded-organic phase with 1 M HCl. The maximum value of the overall volumetric mass transfer coefficient for the IS-RPB extractor was found to be 0.16 s−1 which was superior to that of conventional extractors such as mixer-settler and centrifugal extractors, providing strong confidence for its industrial application.

Impure ions removal from multicomponent leach solution of nickel sulfide concentrates by solvent extraction in impinging stream rotating packed bed

In order to separate zinc, manganese and copper from a mixed chloride solution containing nickel and cobalt, solvent extraction with Di-2-ethylhexylphosphoric acid (D2EHPA) was investigated using an Impinging Stream–Rotating Packed Bed (IS–RPB) contactor in laboratory scale. The effects of operating parameters, such as equilibrium pH, ratio of aqueous to organic flow rates, rotation speed and concentration of D2EHPA amongst other variables were examined. A McCabe–Thiele diagram of the extraction stage predicted that at a flow rate ratio of 1:1, equilibrium pH of 3.5, D2EHPA concentration of 20% (v/v) and rotation speed of 900 rpm, 99.9% of zinc, manganese and copper would be removed within three stages. With regards to the scrubbing results, the co-extracted nickel and cobalt were scrubbed efficiently from the loaded organic solution using 0.8 M HCl, The loaded-organic phase can be reused for extraction process after stripping with 3 M HCl. IS–RPB extraction system have much higher mass transfer rates compared to conventional extractors such as mixer-settler and centrifugal extractor, etc. Finally, each of impure ions in raffinate was below 5 mg/L, completely meeting the requirements of subsequent process of nickel and cobalt separation.

A novel boot strapping algorithm for text extraction in a self-organising neural network model

With rapid growth in internet and its associated communication protocols, need for printed documents to be carried over from one place to another has been reduced to minimise the cost and time. Research contributions in the past have paved the way for implementation of smart and intelligent algorithms to further minimise manual intervention in processing of documents. One such area is the automation of text extraction from documents with increased accuracy and least number of false detections. A wide range of algorithms and methodologies have been reported in the past towards efficient extraction of text from documents which may be online or offline. This research paper proposes an efficient extraction algorithm of text from given set of documents which may or may not be graphic through utilisation of a hybrid SOM-ANN algorithm. The experimentation has been done over a wide variety of inputs and convergence of error in extraction is found to be minimum when compared to other conventional extractors.

Liquid–Liquid Extraction of Yttrium(III) Using 2-Ethylhexyl Phosphonic Acid Mono-2-ethylhexyl (EHEHPA) in a Microreactor: A Comparative Study

Experiments were carried out in a slug flow microreactor to systematically investigate reaction behavior under variation of flow rate, and a comparative study was made. Y-junction microreactor and T-junction microreactor have been used to extract yttrium(III) using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl (EHEHPA or P507). Results show that the maximum extraction efficiency of 90.4% in both microreactors could be achieved corresponding to the minimum flow rate of 10 and 100 μL/min. The values of specific interfacial area remain unchanged with the increase of flow rate, and the specific interfacial area of the Y-junction serpentine microreactor is much higher than that of the T-junction microreactor. Maximum values of volumetric mass-transfer coefficient (1.642 s–1) in the Y-junction microreactor are found to be several orders of magnitude higher than those of the T-junction microchannel (0.043 s–1) and conventional extractors (0.0197 s–1).

A comparative study of liquid-liquid extraction in different rotating bed contactors

This study examines the influence of the internal structure of the rotor of rotating bed contactors on mass transfer characteristics in liquid-liquid extraction. Experiments were carried out in rotating spiral bed, rotating zigzag bed, and rotating packed bed. The system studied was removal of hexavalent chromium from an aqueous solution using Aliquat336 (dissolved in kerosene) as the extractant. The stage efficiency in all the rotating contactors increased with rotational speed and flow rates but decreased with feed concentration. The rotating spiral bed extractor (RSB) provides significant improvement over other rotating packed bed (RPB). The stage efficiency attained in RSB was ∼99% within a bed of radial depth ∼0.06 m at aqueous and organic flow rates of 13.34 × 10−6 m3s−1and 3.34 × 10−6 m3s-1respectively. The overall volumetric mass transfer coefficient is over twenty five times higher than that in conventional extractors like mixer settler and fixed bed.

Liquid-liquid extraction in a novel rotor-stator spinning disc extractor

Abstract This work describes a novel rotor-stator spinning disc extractor (RSSDE), which shows high efficiency of liquid-liquid mass transfer and rapid separation of mixed phases in comparison to conventional extractors. Extraction of phosphoric acid from an aqueous phase to an organic phase was selected as the experiment system. The influence of rotational disc speed (R), volumetric flow rate (Q), and rotor-stator distance (H) on extraction efficiency (η) and volumetric mass transfer coefficient (KLa) are investigated in an RSSDE with a spiral-grooved rotor disc or smooth rotor disc. The results show that the maximum value of η is 98.8% under optimized conditions. η increases with increasing R and decreases with increasing both Q and H. KLa increases as both the increase of R and Q and decreases as the increase of H. The maximum value of KLa is nearly 10 times higher than for a rotating disc column. The mass transfer performance of the spiral-grooved rotor disc is superior to the smooth rotor disc. Correlations of the main parameters such as angular velocity (ω), Q, and H on η and KLa for an RSSDE with both the spiral-grooved rotor disc and the smooth rotor disc are presented. The calculation result shows good coincidence with experimental data.

Microfluidic solvent extraction of Ce (III) and Pr (III) from a chloride solution using EHEHPA (P507) in a serpentine microreactor

Extractive and separation of Pr/Ce using a Y-junction serpentine microreactor, with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (EHEHPA, P507), has been investigated. The results clearly indicate separation factor of Pr/Ce (>3) is to be higher in the microfluidic extraction as compared to separation factor of around 2 to 3 for batch systems. The optimized residence time of 12s in micro-flow is much less than that in batch system (≅300s). The extraction rates for Pr and Ce are found to match first order kinetics with the rate constants being 0.2649s−1 and 0.2279s−1, respectively, which are >20 times higher than those for batch extraction. The volumetric mass transfer coefficients (KLa) for various operating conditions vary between 0.007 and 0.57s−1, which decrease with increase in channel size (channel width and length). The experimentally mass transfer coefficients are compared with those with conventional extractors such as mixer settler and centrifugal extractors.

Separation of lanthanum and cerium from chloride medium in presence of complexing agent along with EHEHPA (P507) in a serpentine microreactor

The effect of operating parameters on the extraction and separation of La and Ce, from chloride solution containing one complexing agent lactic acid, using 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (EHEHPA, P507) as an extractant, has been studied. Results show that extraction efficiencies increase as pH and residence time increase, while decrease with the increasing of channel width and mixture velocity. A better separation effect is obtained using microfluidic extraction at optimal conditions. The extraction rates (0.1214 s−1 for La and 0.3231 s−1 for Ce) determined in microfluidic extraction, are much larger than those (0.0058 s−1 for La and 0.0068 s−1 for Ce) in conventional solvent extractors, which are largely attributed to the higher surface-to-volume ratio achieved in microfluidic experiments. The overall mass transfer coefficients (KLa) increase with increase in mixture velocity, while decrease with increase in channel size including channel width and length. The significant difference in KLa of Ce (0.05–0.162 s−1) as compared to La (0.004–0.129 s−1) imply better separation effect. Compared with conventional extractors such as mixer-settler and centrifugal extractor, microfluidic extraction has much higher mass transfer rates.

Liquid-liquid extraction intensification by micro-droplet rotation in a hydrocyclone

The previous literature reports that using a hydrocyclone as an extractor intensifies the mass transfer and largely reduces the consumption of extractant from 1800–2000 kg h−1 to 30–90 kg h−1. However, the intensification mechanism has not been clear. This paper presents experimental and numerical methods to study the multi-scale motion of particles in hydrocyclones. In addition to the usually considered translational behavior, the high-speed rotation of dispersed micro-spheres caused by the anisotropic swirling shear flow is determined. The rotation speeds of the tested micro-spheres are above 1000 rad s−1, which are much larger than the instantaneous rotation speed in isotropic turbulence. Due to the conical structure of a hydrocyclone, the rotation speed maintains stability along the axial direction. Numerical results show that the particle Reynolds number of micro-droplets in a hydrocyclone is equal to that in conventional extractors, but the particles have high rotation speeds of up to 10,000 rad s−1 and long mixing lengths of more than 1000 mm. Both the rotation of micro-droplets along the spiral trajectories and the intense eddy diffusion in a hydrocyclone contribute to the extraction intensification.

Spread spectrum audio watermarking based on perceptual characteristic aware extraction

This study presents a high-performance audio watermarking scheme using spread spectrum modulation. Unlike conventional extractors which use simple correlation, this watermarking scheme exploits the perceptual characteristic of the watermarked audio before correlation. It is noted that although the watermark extractor works blindly neither which the original audio signal nor the embedded watermark signal is available, however, the spectral power structure of embedded watermark can be estimated using perceptual analysis methods. With this information, the watermark performance is improved by introducing an estimation-equalisation-correlation based extraction mechanism. The pre-equaliser at the extractor is carefully designed to obtain optimised extraction performance. Moreover, the perceptual analysis and shaping method are improved to make sure the watermark estimation is accurate. The perceptual characteristic aware extraction-based watermarking scheme achieves high embedding capacity up to 43 bps/channels, with low perceptual distortion to the host audio. Experiments on real audio signals show that the proposed watermarking scheme achieves high performance and is robust against various types of attacks.

Extraction of dye from aqueous solution in rotating packed bed

The influence of centrifugal acceleration on mass transfer rates in liquid–liquid extraction was investigated experimentally in rotating packed bed (RPB) contactor. The extraction of methyl red using xylene was studied in the equipment. The effect of rotational speed (300–900rpm), flow rate of the aqueous (4.17–20.8×10−6m3/s), and organic phase (0.83–2.5×10−6m3/s) on the mass transfer performance was examined. The maximum stage efficiency attained was ∼0.98 at aqueous to organic flow rate ratio of 10. The results suggest that contactor volume required to carry out a given separation can be reduced by an order of magnitude with RPB in comparison to conventional extractors.

Liquid–liquid extraction in microchannels and conventional stage-wise extractors: A comparative study

The objective of the study is to compare the performance of microchannels and conventional stage-wise extractors for liquid–liquid extraction by using a standard phase system. Three different microchannels – a T-junction microchannel, a serpentine microchannel and a split-and-recombine microchannel – have been used in the experiments. Conventional extractors are represented by a mixer-settler and an annular centrifugal extractor. The phase system used in the experiments is water (succinic acid) n-butanol system which is one of the standard phase systems recommended by the European Federation of Chemical Engineering. The extractors have been compared on the basis of percentage extraction, overall volumetric mass transfer coefficient and specific extraction rate. When compared on the basis of percentage extraction, performance of the microchannels and the conventional stage-wise extractors is found to be almost similar. Maximum values of overall volumetric mass transfer coefficient and specific extraction rates are found to be more in the microchannels than in the conventional stage-wise extractors. The ratio of maximum overall volumetric mass transfer coefficient in microchannels and conventional stage-wise extractors is found to range from 1 to 8.1. The ratio of maximum specific extraction rate in microchannels and conventional stage-wise extractors is found to range between 2.3 and 9.7.

Solvent Extraction and Stripping Studies in Microchannels with TBP Nitric Acid System

Solvent extraction experiments are carried out in a t-junction serpentine microchannel and a split-and-recombine microchannel with TBP-nitric acid system. Stripping experiments have been carried out in the t-junction serpentine microchannel. The effects of residence time and O/A ratio on overall volumetric mass-transfer coefficients are discussed. Flow patterns in microchannels are observed to have more insight into experimental trends. For the same average velocity, the split-and-recombine microchannel is found to give higher overall volumetric mass-transfer coefficient. Overall volumetric mass-transfer coefficients observed for the two microchannels are compared with overall volumetric mass-transfer coefficients reported for conventional extractors.

Multi-staging for extraction of cesium from nitric acid by a single liquid–liquid countercurrent centrifugal extractor with Taylor vortices

Fission products that emit considerable decay heat and radioactivity, such as 137Cs, have a large impact on waste management. Small and high-performance extractor is desirable for separating such nuclei. In this study, we implemented the continuous extraction of Cs from nitric acid in a single liquid–liquid countercurrent centrifugal extractor with Taylor Vortices by calix[4]arene-bis(t-octylbenzo-crown-6)(BOBCalixC6) as an extractant with trioctylamine(TOA) as a suppressant and with 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) as a phase modifier. Because of slow extraction kinetics of this process, extraction with multiple theoretical stages by just replacing conventional extractors into the single centrifugal extractor is difficult. Hence, we improved the dispersion of organic phase by an inner rotor made of lipophilic epoxy resin and elevating the solution temperature to lower the viscosity. Higher temperature was not appropriate from the aspect of chemical equilibrium in this process, but extraction with multiple theoretical stages was found to be possible.

Plant availability of trace elements in sewage sludge-treated soils: methodology¹

Synthetic root exudates were formulated based on the organic acid composition of root exudates derived from the rhizosphere of aseptically grown corn plants, pH of the rhizosphere, and the background chemical matrices of the soil solutions. The synthetic root exudates, which mimic the chemical conditions of the rhizosphere environment where soil-borne metals are dissolved and absorbed by plants, were used to extract metals from sewage-sludge treated soils 16 successive times. The concentrations of Zn, Cd, Ni, Cr, and Cu of the sludge-treated soil were 71.74, 0.21, 15.90, 58.12, and 37.44 mg kg-1, respectively. The composition of synthetic root exudates consisted of acetic, butyric, glutaric, lactic, maleic, propionic, pyruvic, succinic, tartaric, and valeric acids. The organic acid mixtures had concentrations of 0.05 and 0.1 mol L-1 -COOH. The trace elements removed by successive extractions may be considered representative for the availability of these metals to plants in these soils. The chemical speciation of the metals in the liquid phase was calculated; results showed that metals in sludge-treated soils were dissolved and formed soluble complexes with the different organic acid-based root exudates. The most reactive organic acid ligands were lactate, maleate, tartarate, and acetate. The inorganic ligands of chloride and sulfate played insignificant roles in metal dissolution. Except for Cd, free ions did not represent an important chemical species of the metals in the soil rhizosphere. As different metals formed soluble complexes with different ligands in the rhizosphere, no extractor, based on a single reagent would be able to recover all of the potentially plant-available metals from soils; the root exudate-derived organic acid mixtures tested in this study may be better suited to recover potentially plant-available metals from soils than the conventional extractors.

Application of a novel-opposed-jets contacting device in liquid–liquid extraction

Liquid–liquid extraction of the recommended test system, cumene– iso butyric acid–water (CBW) as a typical example of liquid–liquid extraction processes has been carried out in a new two-opposed-jets contacting device (TOJCD). The experimental results clearly indicate that TOJCD provides much higher overall volumetric (capacity) mass transfer coefficients, K L a, than those of conventional extractors. This high overall volumetric (capacity) mass transfer coefficient, K L a, indicates greater performance capability of TOJCD relative to those of conventional contactors. In addition, the effects of the upper disk speed, solution flow rate, disk diameter, and the distance between disks on the extraction efficiency have been investigated. Furthermore, the effectiveness of two-opposed jets was evaluated by employing another new non-opposed-jets contacting device.

Novel Type of Impinging Streams Contactor for Liquid−Liquid Extraction

An experimental study was conducted on liquid-liquid extraction of succinic acid by means of normal butanol from its aqueous solution (BSW), iodine from its aqueous solution by means of kerosene (KIW), and acetic acid by means of distilled water from kerosene (WAK) in a novel type of contactor based on an impinging streams technique. This high-intensity jet contactor provides significant improvement over the conventional extractor because of the impingement of high-velocity feed streams upon one another in a relatively small contactor volume, resulting in a high-turbulent mixing of two phases. As a result of both the impinging process and shear forces exerted on the phases, the overall volumetric (capacity) mass-transfer coefficients, K L a, of up to 15, 23, and 26 min -1 have been obtained for BSW, KIW, and WAK, respectively. The order of magnitudes of the latter coefficients are higher than typical values obtained by conventional extractors. In addition, the effects of the upper disk speed, solution flow rate, disk diameter, distance between disks and the enhancing effect of impinging streams have been investigated. These experimental results verify the capability of the new contactor in liquid-liquid extraction.

Performance of random-walk capacitance extractors for IC interconnects: A numerical study

With ever-shrinking feature geometries, multilevel IC interconnects will greatly influence overall circuit behavior. In particular, efficient numerical evaluation of 3D IC-interconnect capacitance is essential to achieving targeted design goals. Previously, we have reported a new random-walk (RW) algorithm for extracting capacitance of complex multilevel IC interconnects [see, Y.L. Le Coz and R.B. Iverson, Solid-St. Electron. 35, 1005 (1991)]. Here, for the first time, we present a numerical study concerning the influence of interconnect complexity on RW-extractor performance. Of primary interest, are the empirical relationships among geometric complexity, run time, and memory usage. We also include, for reference, comparisons with conventional finite-element (FE) and boundary-element (BI) capacitance extractors. Despite the general computational limitations of these conventional extractors, we have attempted to normalize numerical errors to a single common value. The problem geometry selected for our study consists of a long “bus” wire situated beneath a series of shorter cross wires. Problem complexity is controlled by increasing the bus-wire length and adding cross wires. We have found that at 1% normalized error in bus-wire self-capacitance, the RW extractor has the shortest execution time, which is uniquely independent of problem complexity. In addition, because the RW extractor requires no numerical meshing, an RW:BI:FE memory-usage ratio of 1:10 3:10 7 was observed. We conclude that the RW method may possibly excel in the high-complexity regime characteristic of multilevel IC interconnects.