Two new relationships for slip velocity and characteristic velocity in a non-center rotating column

Torkaman Rezvan,Heydari Mehran,Cheshmeh Javad Najafi,Heydari Ali,Asadollahzadeh Mehdi 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

In this investigation work, liquid-liquid extraction (L.L.E) through three distinctive frameworks have been examined for assurance of slip velocity (S.V), and characteristic velocity (C.V) in a non-center rotating column (N.C.R.C) with a wide extend of factors. Three double frameworks with distinctive interfacial tension comprising of toluene-water (high interfacial tension), n-butyl acetateewater (medium interfacial tension), and n-butanolewater (low interfacial tension) were investigated for tests. Two common relationships for the expectation of S.V and C.V, including phase stream rates, rotor speed, column geometry additionally physical properties, are displayed. The recommended relationships were compared with test information gotten from the writing and the display examination. Findings of this study, the present proposed correlations are more accurate than those previously reported.

Optimization of lanthanum extraction in asymmetric rotation pilot plant column by using central composite methodology

Mehdi Asadollahzadeh,Rezvan Torkaman,Meisam Torab-Mostaedi 한국자원공학회 2020 Geosystem engineering Vol.23 No.2

The present work aimed to optimize the lanthanum extraction efficiency in the pilot-scale asymmetric rotating disc contactor. Optimal batch-scale extraction conditions were determined for the preparation of feed for extraction column (D2EHPA 0.08 mol/L; pH~8). In continuous mode, the optimization with the central composite design approach was performed by using three main parameters, such as continuous phase flow rate, agitation intensity, dispersed phase flow rate. Three responses studied were slip velocity, dispersed phase holdup, and extraction efficiency. The higher value of extraction efficiency for lanthanum extraction shows the main effect of agitation intensity on the dispersed phase holdup, slip velocity, and rate of mass transfer. The optimum conditions for extraction efficiency equal 98.5% were obtained at a rotation speed equal to 7.75 1/s, and phase flow rates equal to 1.25 × 10−5 m3/s. The new correlations are estimated to describe the holdup of the dispersed phase and the slip velocity with high accuracy and R-square values equal to 0.9734 and 0.9670, respectively. The results showed that the pilot plant asymmetric rotating disc column could be used as an appropriate column for the lanthanum extraction from aqueous solution as an example of rare earth metals.

Testing the Implementation of a Pilot-Scale Kühni Column in Reactive and non-Reactive Condition

Asadollahzadeh Mehdi,Torkaman Rezvan,Torab-Mostaedi Meisam 한국자원공학회 2021 Geosystem engineering Vol.24 No.2

In this study, the primary efforts focused on using the Kühni extraction column with optimal energy and extraction efficiency for the removal of zinc ions from aqueous solution. The implementation of the extractive column was investigated in the reactive and non-reactive conditions. The experimental works illustrate that the extraction efficiency and hydrodynamic parameters, particularly depend on the energy input, phase flow rates as well as on the physical properties of the aqueous and organic phases. Among the operating parameters, the choice of the appropriate range for rotation speed plays a significant role for the removal of zinc ions in the pilot-scale Kühni column. The results showed that in the optimal condition for rotation speed, aqueous phase flow rate, and dispersed phase flow rate equal to 181 rpm, 33 L/h, and 21 L/h, respectively, the amount of zinc extraction reaches a maximum of 99.58%.

Feasibility of pilot-scale disc-donut column for continuous cadmium extraction with the perspective of droplet size distribution

Asadollahzadeh Mehdi,Torkaman Rezvan,Torab-Mostaedi Meisam,Heydari Ali 한국자원공학회 2021 Geosystem engineering Vol.24 No.6

Heavy metal removal is a significant problem in various industries. Liquid-liquid extraction is a practical process in recovering these elements. In this study, the behavior of pilot-scale disc-donut column in the extraction of cadmium ions was evaluated. The effects of droplets with the variation size distributions are significant in describing performance and characteristics of an extractor for removing the substrate from aqueous or organic phases. The size distribution of droplets is relative to the interfacial area under steady conditions. To match the size distribution of droplets, the experiments are carried out in reaction and non-reaction conditions. In emulsion regime (pulsing intensity (Af), inlet organic and aqueous phase flow rate (Vc, Vd) equal to 3.3 cm/s, 2.22 mm/s, and 2.22 mm/s, respectively) and under the optimized conditions, 99.7% of the cadmium can be recovered from the aqueous solution. It was found that Weibull distribution gives the best fit at each operation mode while inverse Gaussian distribution gives the most inferior fit. According to a series of statistical analyses, it is shown that the pulsation intensity imposed more influence on drop sizes, and superficial flow rates of both phases are less able to the successful prediction of size distribution of droplets.

Study on the feasibility of using a pilot plant Scheibel extraction column for the extraction and separation of lanthanum and cerium from aqueous solution

Mehdi Asadollahzadeh,Rezvan Torkaman,Meisam Torab-Mostaedi 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.2

Batch and continuous experiments were carried out in a Scheibel extraction column to separate La(III) from Ce(III). Central composite design was used to evaluate the influence of pH, extractant concentration in the batch experiments, and the influence of rotor speed, phase flow rates in the continuous experiments. At optimum conditions (pH 3.5, D2EHPA extractant concentration 0.05 M, rotor speed 128 rpm, dispersed phase flow rate 32 L/h and continuous phase flow rate 18 L/h), high extraction efficiency and separation factor equal to 88.12% and 4.89, respectively, for cerium separation from lanthanum were reasonably well predicted by the model. At higher rotor speed, La(III) and Ce(III) ions move faster from aqueous to the organic phase, which retards the higher interaction between ions and D2EHPA extractant. The results showed that this extraction column could be a potential candidate for the extraction and separation of La(III) and Ce(III) ions or other industrial wastewater.

Extraction of dysprosium from waste neodymium magnet solution with ionic liquids and ultrasound irradiation procedure

Mehdi Asadollahzadeh,Rezvan Torkaman 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.1

This study investigated imidazolium ionic liquids’ capability under ultrasonic irradiation conditions for dysprosium extraction from the aqueous nitrate solution. The main objective was to evaluate the feasibility of ultrasoundassisted extraction techniques compared to conventional solvent extraction. The extraction process was investigated as a function of the ionic liquids and organic extractant, organic/aqueous phase volume ratio, the acidity of the aqueous phase, contact time, ion concentration, temperature, and stripping condition. The outcomes demonstrated that the combination of C6MIM.PF6 and TOPO extractant is more extractable than the mixture of C6MIM.NTf2 and TOPO. The effects of ultrasonic irradiation on the Dy(III) ions show that ion transfer occurs with high extraction efficiency. The variation of logD versus temperature demonstrated that temperature had little impact on the extraction procedure. The recovery of dysprosium ions from the organic phase using 0.5M nitric acid is achieved in stripping studies. The results showed that the extraction and recovery under ultrasonic irradiation and with the presence of ionic liquids proposed a simple and environmentally friendly approach for the purification and separation of rare-earth ions from the permanent magnet wastewater.

Reactive extraction evaluation for vanadium (V) removal in the MRDC column using axial dispersion and central composition approach

Benyamin Shakib,Mehdi Asadollahzadeh,Mohamamd Outokesh,Rezvan Torkaman,Meisam Torab-Mostaedi 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.12

Reactive extraction development was investigated to extract vanadium ions from sulfate solution in the modifiedrotating disc column (MRDC). It was found from batch experiments that D2EHPA and TBP concentrations, initialaqueous phase pH, and the concentration of NH4OH as a stripping agent were optimized equal to 0.3M, 0.36 M, 2, and1M, respectively. In the continuous experiments, the effects of rotor speed, aqueous and organic phase flow rates, andmass transfer direction were investigated on the dispersed phase holdup, mass transfer coefficients, and vanadiumextraction. The experiment design was based on the response surface design to analyze the dependence of responseswith the input parameters. The uncertainty analysis by the Monte Carlo simulation indicates that the rotor speed, reactionconditions, and phase flow rates affected the dispersed phase holdup. By applying the axial dispersion model, theperformance of mass transfer coefficients in terms of agitation speed, aqueous phase flow rate, organic phase flow rate,and mass transfer direction was evaluated under the chemical reaction system. A new model by considering the dimensionlessnumbers has been provided to predict overall mass transfer data based on the dispersed phase.