Mixture Of Tributyl Phosphate Research Articles

Intensified reactive extraction of 4-hydroxypyridine with di(2-ethylhexyl) phosphoric acid in 1-octanol by using tributyl phosphate

Tributyl phosphate (TBP) exhibit significant intensification effect toward the extraction of 4-hydroxypyridine by di(2-ethylhexyl) phosphoric acid in 1-octanol via a more tendency to form (1:1) type complexes. The efficient separation of amphoteric organic compounds from dilute solutions is of great importance in the industrial field. In the present work, the reactive extractions of 4-hydroxypyridine (4-HP) with tributyl phosphate (TBP), di(2-ethylhexyl) phosphoric acid (D2EHPA) and TBP + D2EHPA dissolved in 1-octanol were investigated, respectively. The influences of the initial concentrations of TBP, D2EHPA and TBP + D2EHPA on distribution ratio ( D ) were discussed, as well as the reactive extraction mechanism were proposed. The obvious intensification effect was observed when the mixture of TBP and D2EHPA was used as extractant. The best extraction conditions were found to be of the molar ratio of D2EHPA and TBP at 2:1 and the equilibrium aqueous pH at 3.50–4.50. D values increased with the increase of the total concentration of TBP and D2EHPA in 1-octanol. Especially, the analysis on the extraction mechanisms clearly indicate (i) TBP in 1-octanol shows negligible reactive extraction toward 4-HP, (ii) D2EHPA in 1-octanol exhibits moderate extraction effect by forming 4-HP:D2EHPA (1:1) and 4-HP:2D2EHPA (1:2) type complexes, while (iii) D2EHPA in TBP/1-octanol demonstrates the maximum distribution ratio with the 4-HP:D2EHPA (1:1) type complex domination. The discussion provides new insights on the mechanism and opens a new way for the intensified extraction of amphoteric organic compounds by using the mixture of multiple extractants in the diluent.

PHYSICAL AND CHEMICAL FOUNDATIONS OF THE EXTRACTION REFINING OF NATURAL URANIUM

The paper presents the results of studies of the physicochemical processes of the extraction and nitric acid purification of uranium salts obtained by the method of precipitation of ammonium uranyl carbonate (AUC) from ore solutions of leaching of uranium and polymetallic ores with their subsequent dissolution in nitric acid. It is shown that the process of extraction on a mixture of tributyl phosphate (TBP) in kerosene makes it possible to obtain high-purity uranium oxide. For the selective extraction of impurities, the process of uranium extraction from the nitric acid medium was carried out with a mixture of TBP and di(2-ethylhexyl) phosphoric acid (DEHPA) in kerosene. The first uranium concentration 40…50 g/L simulated the process of uranium desorption, the second ≤ 100 g/L simulated the process of dissolution of uranium oxide. The study of the uranium extraction made it possible to determine the required number of extraction stages to achieve the minimum uranium content in the raffinate and the maximum extractant capacity, which ensured the specified coefficients of uranium purification from metal impurities (V, Mo, etc.). After extraction, the nitric acid raffinate served as a raw material for the production of a mineral fertilizer – sodium nitrate.

A non-destructive dielectric based approach for the rapid determination of tributyl phosphate in dodecane.

Reliable determination of tributyl phosphate (TBP) in suitable diluents is indispensable in studies related to nuclear fuel reprocessing. Herein, we present a rapid and non-destructive dielectric based approach to determine TBP in mixtures of TBP and n-dodecane in the quality control as well as research laboratories associated with nuclear fuel reprocessing. The measurement is based on an in-house developed new class of sensors called pulsating sensors. The heart of the instrument consists of a three gate oscillator circuit that generates the first electronic response directly in the digital domain. With a single capacitive type probe and using a standalone embedded unit, two different ranges of measurement are covered. A detailed investigation on the various factors affecting the probe output is carried out to achieve maximum sensitivity and precision in analysis. It takes less than a minute to take a measurement. The precision in analysis in the reported range of measurement (0.7-35% v/v TBP) lies between 0.15% and 11.4% relative standard deviation, while the absolute error in measurement lies between ±0.02 and ±0.43% (v/v). The response time and limit of quantification are 4.5s and 0.1% (v/v), respectively. The measurements made with the proposed technique are compared with the well-established gas chromatographic technique.

Obtaining Solid Extractants Based on Mixtures of Tributylphosphate and Molecular Iodine and Researching the Extraction of Scandium from Chloride Solutions

Obtaining Solid Extractants Based on Mixtures of Tributylphosphate and Molecular Iodine and Researching the Extraction of Scandium from Chloride Solutions

A Novel Multi-Step Purification Method for Production of Profitable Food Grade Phosphoric Acid and Ammonium Based Fertilizers from a Sedimentary Ore

Effective parameters on producing food grade phosphoric acid and consequently di-ammonium phosphate fertilizer from a sedimentary phosphate ore were investigated in this study. The ore characterization analysis was performed and revealed that there were 32.32% of P2O5 along with some elements such as iron, calcium, magnesium, chlorine, fluorine, arsenic and lead in the ore deposit. Following the initial washing experiments, two methods were used to dissolve ore and multi-step purification of phosphoric acid was performed to remove impurities. Accordingly, the solution had been concentrated using solvent extraction system. The extractant was prepared in a novel way from three-to-one mixture of Tributyl-phosphate and Isopropyl-alcohol. Kerosene was used as a solvent in these experiments. For optimization, the experiments were performed using statistical design method by DX7 software and then high purity phosphoric acid was obtained. Finally, the obtained phosphoric acid was converted to ammonium based fertilizers during optimization tests.

Uranium extraction with modified sorbents

Hydrometallurgical processing of uranium-containing raw materials generates a significant amount of liquid industry-related waste, namely waste solutions that require disposal. Sorption is known as one of the most effective methods for purifying liquid matters contaminated with radionuclides. Various modification options are being developed for the purpose of using natural sorbents and increasing their sorption capacity. The authors proposed the methods for modifying natural aluminosilicate and coal-mineral raw materials. Zeolite found at the Kusmurun deposit and shungite from the Koksu deposit were selected for the research. The methods are based on obtaining solid-phase extractants. It was proposed to modify natural sorbents with a mixture of tributyl phosphate and di2-ethylhexyl phosphoric acid in kerosene, as well as a mixture of phosphoric acid and polyacrylamide. It was demonstrated that the first method is preferable for zeolite, and the second one for shungite. The research addressed the sorption properties of modified sorbents in static and dynamic modes. Uranium sorption isotherms were plotted. The maximum sorption capacity and the Langmuir constant were calculated. The research allowed synthesizing an organopolymer based on shungite, glycidyl methacrylate, orthophosphoric, and hydroxyethyl diphosphoric acids. Its sorption properties were studied under dynamic conditions. Its sorption capacity was assessed in comparison with modified natural sorbents.

Extraction of Scandium Halides with Mixtures of Tributylphosphate and Molecular Iodine

The extraction of scandium chlorides, bromides and iodides from aqueous solutions with mixtures of tributyl phosphate (TBP) and molecular iodine was studied. Extraction of scandium halides using TBP with the addition of iodine increases by more than 100 times. Salt distribution coefficients increase in the series ScCl3

Evaluation of the Possibility of Obtaining Potassium Bromide via Extraction from Naturally Occurring Calcium Chloride Brines by a Mixture of Tributyl Phosphate and Molecular Iodine

Data are obtained concerning the extraction of hydroiodic, hydrobromic, and hydrochloric acids from solutions using a mixture of tributyl phosphate and molecular iodine. A significant increase in the extraction of these acids by tributyl phosphate in the presence of iodine has been revealed. According to extractability, these acids can be arranged in the series of HCl < HBr < HI. The separation factors for these hydrohalic acids are very high, which can provide their efficient separation in a countercurrent process. The possibility has been established for the extraction of bromine from calcium chloride brines with obtaining potassium bromide via washing bromide extracts from metals by acids and reextracting bromide ion by alkaline reagents such as potassium hydroxide or potash solutions.

Influence of Light and Temperature on the Extractability of Cerium(IV) as a Surrogate of Plutonium(IV) and its Effect on the Simulation of an Accidental Fire in the PUREX Process.

Modeling of plutonium(IV) behavior during an accidental fire in a reprocessing plant was considered using various non-radioactive metallic surrogates. Among those elements, cerium(IV) was supposed to be a suitable candidate due to possible formation of a complex with TPB, but its extractability and stability have not been studied previously under representative plutonium uranium reduction extraction (PUREX) conditions. In this work, we investigated the chemical analogy between cerium(IV) and plutonium(IV) in this extractive process and combustion thereof. Distribution ratios are reported for acidities of 1–4 mol L–1 in equal volumes of nitric acid and a 30:70 mixture of tributylphosphate and hydrogenated tetrapropylene. The influences of light, temperature, and extraction time were studied by UV–vis spectroscopy. The results showed that cerium(IV) is extracted quantitatively but is reduced over time to cerium(III) in the organic mixture. Spectrophotometric investigations of this reaction kinetics revealed an apparent rate constant k of 0.021 ± 0.002 mol0.5 L0.5 min–1 at 298 K and an apparent fractional reaction order of 0.5. The activation energy of this reduction was found to be around 82 ± 2 kJ mol–1 by the Arrhenius plot method. The combustion of mono- and biphasic solutions prepared with a cerium(IV) concentration of 10 g L–1 revealed that the extracted complexes, Ce2O·6NO3·3TBP(org) or Ce4O4·8NO3·6TBP(org), are reduced during the combustion. Compositions of the resulting ashes and soot were analyzed and highlighted the presence of pyrophosphates and polycyclic aromatic hydrocarbons, with some traces of cerium. Ce(IV) is not suitable to represent Pu(IV) from a chemical point of view in HNO3/TBP–HTP solutions.

Rapid Clogging of High-Efficiency Particulate Air Filters During In-Cell Solvent Fires at Reprocessing Facilities

Recent Japanese nuclear regulations have focused on the hazards of in-cell solvent fires at reprocessing facilities. In this work, a mixture of tributyl phosphate and dodecane-based solvents was burned to generate an aerosol composed of soot and unburned solvent that was then loaded onto a high-efficiency particulate air filter simulating the ventilation system of reprocessing facilities. A radical increase of differential pressure occurred in the filters during these tests after the dodecane burned out from the solvent in a phenomenon we named as rapid clogging, likely caused by the burnout of dodecane. This relationship provides valuable insight into the establishment of new regulations for reprocessing facilities. Moreover, an analysis of the aerosol revealed an increase in unburned solvent content and aerosol particle size generated during the rapid clogging. As such, the rapid clogging may be caused by the unburned solvent release or interactions between the soot and unburned solvent vapor. Overall, this work indicates that clogging of ventilation filters during solvent fires may occur more rapidly than previously estimated.

Scandium Extraction from Chloride Solutions by a Mixture of Tributyl Phosphate and Molecular Iodine

It has been established that the addition of elemental iodine significantly enhances the extraction of scandium by means of tributylphosphate. The metal distribution coefficients exhibit an increase with increasing TBP and iodine concentration in the organic phase as well as with increasing chloride ion concentration in the aqueous phase. As an outsalting agent, chlorides of alkali, alkaline earth and other weakly extracted metal cations can be used. The process is promising for the extraction of scandium from solutions of hydrochloric- acid leaching of mineral and man-made materials.

Specific Features of Scandium Chloride Extraction with a Mixture of Tributyl Phosphate and Molecular Iodine

Features of interphase distribution of scandium chloride in the systems containing tributyl phosphate and molecular iodine have been analyzed. Significant electrolytic dissociation of the formed complex scandium chloride with tributyl phosphate and iodine in the organic phase (almost complete at tributyl phosphate concentration 80–100%) has been observed. The increase in electroconductivity of the solutions of scandium chloride has been most prominent at the ratio of scandium chloride and iodine corresponding to the formation of monosolvate. Accounting for electrolytic dissociation in the organic phase allowed the description of the interphase extraction of scandium chloride in the studied systems.

Solvent Extraction of Rare Earth Elements from a Nitric Acid Leach Solution of Apatite by Mixtures of Tributyl Phosphate and Di-(2-ethylhexyl) Phosphoric Acid

Solvent extraction of rare earths from nitrate leach liquor of apatite using mixtures of tributyl phosphate (TBP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) was studied. The effects of nitrate and hydrogen ion concentration of the aqueous phase as well as the composition and concentration of extractants in the organic phase on the extraction behavior of lanthanum, cerium, neodymium, and yttrium were investigated. The distribution ratio of REEs increases by increasing the nitrate concentration in aqueous phase and concentration of extractants in organic phase, but the hydrogen ion concentration in aqueous phase has a decreasing effect. Yttrium as a heavy rare earth is more sensitive to these parameters than light rare earth elements. Although the composition of organic phase has a minor effect on the extraction of light rare earths, the percent of extraction of yttrium decreases dramatically by increasing the TBP content of organic phase. Mixtures of TBP and D2EHPA can show either synergism or antagonism extraction depending on the concentration and composition of extractants in organic phase. The best condition for separating rare earth elements in groups of heavy and light REEs can be achieved at high nitrate concentration, low H+ concentration, and high concentration of D2EHPA in organic phase. Separation of Ce and La by TBP and D2EHPA is practically impossible in the studied conditions; however, low nitrate concentration and high hydrogen ion concentration in aqueous phase and low concentration of extractants in organic phase favor the separation of Nd from other light rare earth elements.

Gamma Radiation Thermal Stability of Two-Phase Mixtures of Nitric Acid with Degraded TBP in a Closed Vessel

The influence of thermal and gamma radiation effects on the characteristics of the thermal explosion of mixtures of tributyl phosphate (TBP) and nitric acid was studied. The products of sequential radiolysis and pyrolysis of TBP were determined to have little effect on the thermal stability of mixtures of TBP and nitric acid. The onset temperatures of exothermic processes leading to a thermal explosion were slightly decreased only by the absorbed dose of 2 MGy. The thermal stabilities of solutions of TBP in n-dodecane and diluent C-13, consisting of a mixture of saturated hydrocarbons, were investigated. The experimental results indicate that the irradiation decreased the onset temperature of the exothermic processes in mixtures of nitric acid with TBP solutions in a hydrocarbon diluent; the onset temperature decreased by 5°C to 7°C for n-dodecane and by 9°C to 13°C for C-13, as compared to unirradiated extractants.

Experimental study on thermal hazard of tributyl phosphate-nitric acid mixtures using micro calorimeter technique

During PUREX spent nuclear fuel reprocessing, mixture of tributyl phosphate (TBP) and hydrocarbon solvent are employed as organic solvent to extract uranium in consideration of radiation contaminated safety and resource recycling, meanwhile nitric acid is utilized to dissolve the spent fuel into small pieces. However, once TBP contacts with nitric acid or nitrates above 130°C, a heavy “red oil” layer would occur accompanied by thermal runaway reactions, even caused several nuclear safety accident. Considering nitric acid volatility and weak exothermic detection, C80micro calorimeter technique was used in this study to investigate thermal decomposition of TBP mixed with nitric acid. Results show that the concentration of nitric acid greatly influences thermal hazard of the system by direct reactions. Even with a low heating rate, if the concentration of nitric acid increases due to evaporation of water or improper operations, thermal runaway in the closed system could start at a low temperature.

Tributyl phosphate-[C&lt;sub&gt;n&lt;/sub&gt;min][Tf&lt;sub&gt;2&lt;/sub&gt;N]を用いた塩酸溶液からの希土類元素の抽出および逆抽出

Mutual separation of rare earth ions is very difficult because of their similar chemical properties. In this study, extraction of Nd (III), Dy (III), and Pr (III) from hydrochloric acid solution and their back extraction have been investigated using the mixture of tributyl phosphate, TBP, and 1-alkyl-3-methylimidazoliumbis[ (trifluoromethyl) sulfonyl]imide, [Cnmim][Tf2N] (n, the alkyl chain length, was 2, 4, and 6), in order to clarify the possibility of mutual separation and recovery of these elements. Synergistic effect between TBP and [Cnmim][Tf2N] was found because the extraction was highly enhanced using their mixture, while the extraction by the individual reagent was very low. Although the extraction was increased with a decrease in the n value, mutual separation was difficult because the extraction behavior was similar to one another. Ammonium formate was found to be effective as a back extraction reagent because Pr (III) and Nd (III) were precipitated out as formates while Dy (III) was quantitatively back extracted without precipitation. Precipitation formation was faster in Pr (III) than Nd (III). Based on these results, a possibility of the mutual separation among these three ions was shown.

Solvent extraction of thorium from nitrate medium by TBP, Cyanex272 and their mixture

The extraction behavior of thorium(IV) has been investigated with tri-butyl phosphate (TBP) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272) in kerosene from nitrate medium. The effect of operating variables including time, aqueous phase acidity (pH), extractant concentration and temperature were investigated. This study also examined the synergistic enhancement of the extraction of thorium(IV) from nitrate medium by mixtures of TBP and Cyanex272 for the first time. The optimum synergistic enhancement factor of 3.86 was obtained at a Cyanex272/TBP molar ratio of 1:4.

Development of a Submerged Thermal Plasma Process for Combustion of Organic Liquid Waste

A process for the destruction of organic liquid waste has been developed in which a nontransferred arc plasma torch is operated with oxygen as the plasma gas; the originality of this process is that the plasma jet composed by the plasma forming gases and the combustion products is immersed in an aqueous solution: the objective is to convert the organic fraction into CO2 and H2O, to condense the H2O, and to trap in solution the mineral content of the waste. In addition to maintain the process at room temperature, the solution also ensures most of the functions of an off-gas treatment system: cooling, filtration, and neutralization. We describe the development of the experimental setup developed on the basis of extended test results, with particular attention to the head-end stages of the torch designed to improve the combustion efficiency. The results presented here are focused on incineration of a mixture of tributylphosphate and dodecane: mineralization rate is better than 99 % and phosphorus capture is better than 98 %.

Operating Conditions of Hollow Fiber Supported Liquid Membrane for Phenol Extraction from Coal Gasification Wastewater

The extraction and recycling of phenol from high concentration coal gasification wastewater has been studied using polypropylene (PP) hollow fiber membrane and polyvinylidene fluoride (PVDF) hollow fiber membrane as liquid membrane support, the mixture of tributyl phosphate (TBP) and kerosene as liquid membrane phase, and sodium hydroxide as stripping agent in the process of extraction. The experiments investigated the effect of the operating conditions of the hollow fiber supported liquid membrane, such as aqueous phase temperature and the connection forms of membrane modules, on the extraction efficiency of phenol from high concentration coal gasification wastewater. The conclusions obtained from lab scale experiments provided guidance for scale-up experiments. So, in the scale-up experiments, three membrane modules connected in parallel, then three membrane modules connected in series were used to increase the treatment capacity and improve the treatment effect, under the operating conditions of wastewater temperature 20 ˚C, PH 7.5~8.1, flow rate 100 L/h and the concentration of stripping phase 0.1 mol/L, stripping phase flow rate 50 L/h, the extraction efficiency of the PP-TBP supported liquid membrane system was 87.02% and the phenol concentration of effluent was 218.14mg/L. And the phenol concentration of effluent met the requirements of further biodegradation treatment.

Incineration of radioactive organic liquid wastes by underwater thermal plasma

This work deals with incineration of radioactive organic liquid wastes using an oxygen thermal plasma jet, submerged under water. The results presented here are focused on incineration of three different wastes: a mixture of tributylphosphate (TBP) and dodecane, a perfluoropolyether oil (PFPE) and trichloroethylene (TCE). To evaluate the plutonium behavior in used TBP/dodecane incineration, zirconium is used as a surrogate of plutonium; the method to enrich TBP/dodecane mixture in zirconium is detailed. Experimental set-up is described. During a trial run, CO2 and CO contents in the exhaust gas are continuously measured; samples, periodically taken from the solution, are analyzed by appropriate chemical methods: contents in total organic carbon (COT), phosphorus, fluoride and nitrates are measured. Condensed residues are characterized by RX diffraction and SEM with EDS. Process efficiency, during tests with a few L/h of separated or mixed wastes, is given by mineralization rate which is better than 99.9 % for feed rate up to 4 L/h. Trapping rate is also better than 99 % for phosphorous as for fluorine and chlorine. Those trials, with long duration, have shown that there is no corrosion problems, also the hydrogen chloride and fluoride have been neutralized by an aqueous solution of potassium carbonate.