Loading...
Search for:
solvent-extraction
0.006 seconds
Total 94 records
Synergistic effect of MEHPA on co-extraction of zinc and cadmium with DEHPA
, Article Minerals Engineering ; Volume 17, Issue 1 , 2004 , Pages 89-92 ; 08926875 (ISSN) ; Moradkhani, D ; Darvishi, D ; Askari, M ; Behnian, D ; Sharif University of Technology
2004
Abstract
Simultaneous extraction of zinc and cadmium by a mixture of di-2-ethyl hexyl phosphoric acid (DEHPA) and mono-2-ethyl hexyl phosphoric acid (MEHPA), and the synergistic effect of MEHPA on co-extraction of zinc and cadmium with DEHPA have been investigated. It was shown that the extraction of zinc and cadmium by DEHPA and/or MEHPA can be increased by an increase of pH. The results also illustrate that the pH0.5 of zinc, by increase in MEHPA from 0.1 to 8 vol%, did not vary significantly while that of cadmium varies from 0.63 to 2.4. In other words MEHPA prevents selective extraction of zinc from aqueous media containing both zinc and cadmium. Studies on the selective separation parameter...
Uranium Recovery from Sludge of Evaporation Lagoons of Isfahan’s UCF Plant
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Ghaemi, Ahad (Supervisor) ; Ghasemi, Mohammad Reza (Co-Advisor)
Abstract
Nuclear energy is one of the most important sources of energy from the economical point of view and also in terms of cleanliness and safety. Hence, strategically, uranium is one of the most basic elements of the earth and nowadays, the importance of this element is more marked due to the nuclear industry developement. Therefore, uranium recovery from the wastes generated during nuclear fuel production in Isfahan’s uranium conversion plant- in which yellow cake is converted to uranium hexafluoride- is quite pivotal. In this experimental research, uranium is extracted from the sludge of evaporation lagoons of Isfahan’s UCF plant via solvent extraction method. Execution of this project in an...
Thermodynamics of extraction of Zn2+ from sulfuric acid media with a mixture of DEHPA and MEHPA
, Article International Journal of Engineering, Transactions B: Applications ; Volume 17, Issue 2 , 2004 , Pages 191-200 ; 1728-144X (ISSN) ; Keshavarz Alamdari, E ; Sharif University of Technology
Materials and Energy Research Center
2004
Abstract
Thermodynamics of extraction of Zn2+ from sulfuric acid media contacting to a mixture of DEHPA and MEHPA diluted with 80 wt% aromatic - aliphatic kerosene with a constant DEHPA to MEHPA ratio is investigated at different acidities, concentrations and temperatures. As a result, the extraction reaction is found to be endothermic with a zinc distribution factor that increases with increasing of the temperature, acidity of the solution and the concentration of the extradant. The mechanism of the extraction reaction is shown to be different for pH > 1 with that at pH <1. The pH of the aqueous media has also an important influence on progressing of the extraction reaction
Extraction of molybdenum (VI) and vanadium (V) from nitrate solutions using coupling of acid and solvating extractants
, Article International Journal of Engineering, Transactions A: Basics ; Volume 32, Issue 10 , 2019 , Pages 1366-1371 ; 17281431 (ISSN) ; Torab Mostaedi, M ; Outokesh, M ; Asadollahzadeh, M ; Sharif University of Technology
Materials and Energy Research Center
2019
Abstract
In this study, solvent extraction method has been utilized for separation of molybdenum and vanadium from nitrate solution by utilizing coupling of acid and solvating extractants (D2EHPA and TBP extractants). The outcomes demonstrated that synergistic solvent extraction improves stability of formatted complexes for transfer to the organic phase. The main parameters such as pH value, concentration of extractants, NH4OH concentration as the stripping agent and contact time were optimized at 0.4, 15% (v/v) D2EHPA, 10% (v/v) TBP, 2 M and 30 min, respectively. The maximum separation factor of 24.84 was obtained with a new synergistic mixture of D2EHPA and TBP diluted with kerosene. According to...
Separation of Re and Mo from roasting-dust leach-liquor using solvent extraction technique by TBP
, Article Separation and Purification Technology ; Volume 86 , February , 2012 , Pages 143-148 ; 13835866 (ISSN) ; Darvishi, D ; Haghshenas, D. F ; Yousefi, N ; Sadrnezhaad, S. K ; Sharif University of Technology
Abstract
Re/Mo separation is studied by a new solvent extraction technique which is based on extraction mechanisms of the constituent metals. Based on McCabe-Thiele plots, a flow diagram has been proposed for separation and purification of Re over Mo. Re-recovery section of the diagram shows that Re is extracted when major amount of Mo is removed. For removal of the remained Mo, a two-stage extraction is required at pH = 2 and V a/V o = 1. In order to obtain Re, the resulted aqueous phase is stripped by adding sulfuric acid. According to the results, while more Re is extracted at less pH, optimum extraction of Mo happens at pH = 1.2. Re selectivity over Mo maximizes by approaching of the pH to zero
Recovery of Rhenium From Ferromolybdenum Furnace
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhaad, Khatiboleslam (Supervisor) ; Hakim, Manouchehr (Supervisor)
Abstract
In this work, the recovery of rhenium from ferromolybdenum furnace outgoing dust in semi industrial scale was conducted. The ferromolybdenum furnace outgoing dust contains rhenium as major part and large amounts of molybdenum plus Iron and copper as impurities. An overall flow sheet, consist of leaching, solvent extraction and precipitation methods, was design to recovery and purification of rhenium. Firstly, ferromolybdenum furnace outgoing dust was subjected to leaching treatment by 10 g/L sulfuric as solvent at 85 C. Secondly, solvent extraction method was employed, using LIX984N 10 %vol, to separate copper from rhenium containing solution. The results of MacCab thiele diagram for...
Uranium Recovery from Liquid Waste of UCF by Solvent Extraction Method
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Taghizadeh, Mohammad (Supervisor) ; Ghasemi, Mohamad Reza (Co-Advisor)
Abstract
The Atomic Energy Organization of Iran (AEOI) has launched a program of low level waste management. This program also includes waste produced at Uranium Conversion Facility (UCF) of Esfahan. The liquid waste, which was generated during the operation of plant and concentrated in lagoon, was characterized for the development of the treatment process. The aim of this study was to recovery of uranium content of liquid waste in the lagoon. The recovery of uranium has the advantage of saving this valuable metal and the avoidance of unacceptable discarding solution to the environment. Uranium may be recovered from an aqueous solution by precipitation, solvent extraction and ion exchange....
Extraction of Oxidized Sulfur Compounds of Gas Oil from Oxidation Desulfurization Reactor Products
,
M.Sc. Thesis
Sharif University of Technology
;
Sayf Kordi, Ali Akbar
(Supervisor)
;
Ghaedian, Maryam
(Supervisor)
Abstract
It is well known that sulfur removal from petroleum is necessary for both industrial and environmental reasons. Sulfur in petroleum products corrodes parts of internal combustion engines and refineries due to the formation of sulfur oxyacids and causes major air pollution and acid rain due to exhaust from diesel engines and emission of sulfur oxides. Hydrodesulfurization (HDS), biodesulfurization (BDS), extraction by ionic-liquids (ILs), selective adsorption, alkylation desulfurization and oxidative desulfurization (ODS) are some methods, can be effective in removal of sulfur compounds. Among these new processes, ODS appears to be particularly promising and is currently receiving increasing...
A Detailed Study on Extraction of Uranium from Mother Leach Liquor (of Uranium Mills) by TOA Extractant and Development of a Thermodynamical Model for it
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Safdari, Jaber (Supervisor) ; Mallah, Hassan (Co-Advisor)
Abstract
In many uranium mines such as gachin-bandarabbas, sulfuric acid is used for leaching operation on ore after crushing operation. This leach liquor, containing uranium, is extracted by specific solvent, including extractant like TOA. However, this operation, named Amex, have been used for many years, there is a vacancy for a detailed thermodynamical studying on uranium extraction from leach liquor.To have a thermodynamical model, we need information about the equilibrium concentration of all the components that may have effect on uranium extraction and also concentration of solvent, pH, phase ratio and activity coefficient alteration. This model must have the ability to predict the equilibrium...
Separation of rhenium and molybdenum from molybdenite leach liquor by the solvent extraction method
, Article Minerals and Metallurgical Processing ; Volume 30, Issue 1 , February , 2013 , Pages 53-58 ; 07479182 (ISSN) ; Yoozbashizadeh, H ; Mohammadi, M ; Abazarpoor, A ; Maarefvand, M ; Sharif University of Technology
2013
Abstract
Molybdenum resources around the world are mainly associated with porphyry copper ores. Molybdenite (MoS2) is the main Mo mineral that has rhenium in its crystal lattice. This paper investigates the recovery of rhenium and molybdenum from a molybdenite concentrate using a hydrometallurgical treatment method. The molybdenite concentrate is leached with nitric acid and subjected to solvent extraction to recover and separate rhenium and molybdenum from the leached liquor. The effects of pH and the chemicals' concentration on extraction characteristics of Mo and Re are investigated to define the best condition for selective extraction of these metals. The tested leached liquor contained of 8.2...
Investigation of Equilibrium and Kinetics of Uranium Solvent Extaction by Cyanex 301 Using a Single Drop Column
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Torab-Mostaedi, Meisam (Supervisor)
Abstract
Uranium separation from other metals in ore and nuclear waste is one of the most important stagesin nuclear fuel cycling. Solvent extraction is the common method for uranium extraction that reagent plays important rule in this technique. In this investigation, uranium solvent extraction is carried out by Cyanex 301 as reagent from nitric acid. At beginning, equilibrium batch extraction was carried and the effect of parameters such as pH, reagent concentration, temperature, shaking time of two phases, volumetric ratio of two phases, diluent and nitric acid concentration on extraction was investigated and optimum value of parameters was calculated. Uranium concentration effect was also...
Recovery of Rhenium From Produced Leaching Solution of Sarcheshmeh Molybdenite Concentrate
, M.Sc. Thesis Sharif University of Technology ; Yoozbashizadeh, Hossein (Supervisor)
Abstract
In this study, molybdenum and rhenium extraction from alkaline solution of electro-oxidation leachinng of Sarcheshmeh molybdenite concentrate by solvent extraction using organophosphorous organic solvents, under different conditions has been investigated. The studied variables were organic solvent concentration, ratio of organic phase to aqueous phase and pH. Design Expert software and Central Composite Design method was performed to evaluate the effect of parameters and optimize recovery conditions. Molybdenum was extracted via Di-2-EthyHexyl Phosphoric Acid (D2EHPA) organic solvent diluted in kerosene initially, in order to reduce molybdenum ions interruptions during extraction of rhenium....
Iron Removal from Copper Electrowinning Procces
, M.Sc. Thesis Sharif University of Technology ; Askari, Masood (Supervisor)
Abstract
Iron is a common impurity in copper minerals. The presence of iron in hydrometallurgical copper PLS causes continuous reactions between Fe(II) and Fe(III) ions. In order to improve energy efficiency and product quality iron removal shall be done. In this study separation of iron from Sarcheshme copper leaching liquor containing 6 g/L Fe, was conducted by solvent extraction using D2EHPA in kerosene. Chloric acid solution was used to strip the loaded iron from organic phase. Results of extraction experiments designed by taguchi method showed 92.49% iron recovery and 2.44% copper extraction under optimum condition. Using same method for stripping experiments, it was found that variation of time...
Optimization of the Processes Parameters for Solvent Extraction and Precipitation of Thorium from Chahgaz Mine Ores Leach Liquor
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Zare Tavakolli, Hassan (Supervisor) ; Godocynejhad, Davood (Co-Supervisor)
Abstract
This research investigates and optimizes solvent extraction parameters for separat1ing thorium from the leach solution of the uranium-bearing ore at the ChahGaz mine. The study is applied research aimed at achieving technical knowledge of thorium extraction and purification from thorium-bearing ore through hydrometallurgical processes to obtain thorium concentrate and provide laboratory and semi-industrial flotation. The results obtained from this project lead to the production of thorium concentrate, which can later be utilized in industrial-scale applications. In this project, the influential parameters in the solvent extraction process were simultaneously examined through experimental...
Thermodynamics of extraction of RE O4 - from aqueous sulfuric acid media with Tri-n-butyl phosphate dissolved in kerosene
, Article Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science ; Volume 32, Issue 1 , 2001 , Pages 5-10 ; 10735615 (ISSN) ; Keshavarz Alamdari, E ; Sharif University of Technology
2001
Abstract
Rhenium distribution between Tri-n-butyl phosphate (TBP) dissolved in kerosene and sulfuric aqueous media is investigated under different temperatures, acidities, and TBP concentrations. Results show an exothermic extraction reaction with a distribution factor that decreases with the increase of the temperature and increases with the increase of the acidity and the TBP concentration. The stoichiometry of the reaction indicates neutralization of 1 mole of H+ with 1 mole of ReO4- and solvating of a neutral molecule with four molecules of TBP. The structure of the complexes formed is, therefore, 4TBP · HReO4. The apparent Gibbs free energy of the formation of 4TBP · HReO4 from TBP, ReO4-, and...
Mass transfer evaluation in a multi-impeller extractor for reactive Mo (VI) extraction from aqueous Sulphate solution by utilizing coupling of acid and solvating Extractants
, Article Heat and Mass Transfer/Waerme- und Stoffuebertragung ; Volume 56, Issue 6 , 2020 , Pages 1995-2006 ; Torab Mostaedi, M ; Outokesh, M ; Asadollahzadeh, M ; Sharif University of Technology
Springer
2020
Abstract
In this study, mass transfer experimental data from the present column with 70 cm active column length and 11.3 cm internal diameter were interpreted for molybdenum extraction with a mixture of D2EHPA and TBP in terms of the axial diffusion model. The influence of extractants concentration and the initial aqueous pH have studied in the bench-scale experiments. The experimental finding demonstrated that the synergistic solvent extraction increases the constancy of the extracted complexes for transfer into the organic phase. The effect of operating parameters, including agitation speed and inlet phase velocities on the overall mass transfer coefficients under the chemical reaction system, is...
Optimization of the Solvent Extraction of Rhenium from Acidic Solution Produced by Pressure Leaching of Molybdenite Concentrate
, M.Sc. Thesis Sharif University of Technology ; Yoozbashizadeh, Hossein (Supervisor)
Abstract
The extraction of molybdenum and rhenium from acidic solution produced by pressure leaching of molybdenite concentrate, using organophosphorus solvents has been investigated. First, extraction of molybdenum by Di-2-EthyHexyl Phosphoric Acid (D2EHPA) extractant dissolved in kerosene diluents was done. Extraction experiments were designed using Taguchi L16b orthogonal array. The effects of four factors: Shaking time, Organic solvent concentration, Organic to aqueous phase ratio, pH were studied in four levels. Optimum conditions occur at: shaking time: 35 min, organic solvent concentration: 30 volumetric percent, organic to aqueous phase ratio: 3, pH: 7 and molybdenum is completely extracted....
Oxidative Desulfurization of Light Fuel Oils
, Ph.D. Dissertation Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor) ; Shahrokhi, Mohammad (Supervisor)
Abstract
Oxidative desulfurization (ODS) is one of the desulfurization processes that posseses several important advantages such as mild operating conditions. In the present work, oxidative desulfurization of kerosene with a total sulfur content of 2335 ppm and gas oil with a total sulfur content of 7990 ppm were carefully investigated. By evaluation of different oxidation systems, the hydrogen peroxide-formic acid system was selected for the oxidation of sulfur-containing compounds of the light fuel oils. The effects of main operating parameters of the oxidation system including temperature, hydrogen peroxide to sulfur molar ratio (O/S), and formic acid to sulfur molar ratio (Acid/S) on the...
Investigation on Novel Methods of Precious Metals Recovery from Spent Catalysts
, M.Sc. Thesis Sharif University of Technology ; Kazemeini, Mohammad (Supervisor)
Abstract
High demand and price and restricted availability of Platinum Group Metals (PGMs) have made platinum recovery a major field of study for researchers and industries. Various methods have been introduced for this purpose. Ion exchange, leaching and liquid-liquid extraction (LLE) are just a few examples. Nowadays Solvent Extraction (SX) is one of the most challenging areas of study for platinum recovery from spent catalysts due to its simplicity and optimum cost. In this study, the commercial spent catalyst’s platinum was dissolved in aqua-regia after XRF analysis. Then it was extracted by the organic material Trioctylphosphineoxide diluted in toluene in the presence of Alkaline metal salts....
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Mallah, Mohammad Hassan (Supervisor) ; Safdari, Jaber (Supervisor)
Abstract
In many uranium mines such as gachin-bandarabbas, use sulfuric acid for leaching operation on ore. This leach liquor, containing uranium, is extracted by organic solvent, such as D2EHPA (dapex process ).althogh this process have being used for many years, there is a vacancy for detailed thermodynamical studying on uranium extraction of uranium from leach liquor. To have a thermodynamical model, we need information on equilibrium concentration of all component that may have effect on uranium extraction in addition we need concentration of solvent , pH, phase ratio and activity coefficient.such a model must have the ability to predict the equilibrium concentration in alloperation condition....