Showing papers on "Raffinate published in 2016"

Selective Extraction of Am(III) from PUREX Raffinate: The AmSel System

Abstract: The separation of actinides(III) from used nuclear fuel is a key step for the recycling of used nuclear fuel in innovative fuel cycles. However, high neutron dose rates and heat load of short-lived curium isotopes complicate the production and handling of new nuclear fuel containing curium(III) and americium(III). Therefore, new processes have to be developed separating only americium(III) from PUREX (Plutonium-Uranium Recovery by Extraction) raffinate. This is achieved by coextracting An(III) and Ln(III) from PUREX raffinate using N,N,N’,N’-tetraoctyl-diglycolamide (TODGA), followed by the subsequent selective stripping of Am(III) by a water-soluble bis-triazinyl-bipyridin (sodium 3,3’,3’’,3’’’-([2,2’-bipyridine]-6,6’-diylbis(1,2,4-triazine-3,5,6-triyl))tetrabenzenesulfonate, SO3-Ph-BTBP). The selectivity for Am(III) over Cm(III) is SFCm(III)/Am(III) ≈ 2.5, due to the inverse selectivity of TODGA and SO3-Ph-BTBP. Additionally, a separation factor up to 1200 is achieved for the separation of Eu(II...

Highly selective separation of individual platinum group metals (Pd, Pt, Rh) from acidic chloride media using phosphonium-based ionic liquid in aromatic diluent

Abstract: An effective solvent extraction-based method has been developed to recover individual platinum group metals (PGMs) (i.e. Pd, Pt and Rh) with high purity from acidic chloride media using phosphonium-based ionic liquid Cyphos IL 101 ([P66614]+Cl−) diluted in xylene used as a model of industrial diluents such as SOLVESSO 150. The system showed the selective co-extraction of Pd(II) and Pt(IV) from a feed solution containing 100 mg L−1 Pt(IV), 55 mg L−1 Pd(II), and 25 mg L−1 Rh(III) in HCl via an anion exchange mechanism, leaving Rh(III) in the raffinate. A McCabe–Thiele diagram demonstrated the quantitative extraction of Pd(II) and Pt(IV) with 0.6 g L−1 [P66614]+Cl− with two counter-current stages at an organic/aqueous (O/A) phase volume ratio of 3/2 at 298 K. The stoichiometry of complexes formed in the organic phases was determined using Job's method and further characterized by 1H, 13C, 31P NMR and UV-vis spectroscopy. More importantly, a two-step stripping strategy was successfully adapted to treat the loaded organic phases with low aggressive media NaSCN and thiourea/HCl for the selective recovery of Pt(IV) and Pd(II), respectively, with high purity >99.9% (w). Three counter-current stages are required for the quantitative stripping of Pt(IV) with 0.1 mol L−1 NaSCN at an O/A ratio of 3, whereas the total stripping of Pd(II) with 0.01 mol L−1 acidic thiourea requires only one stage at an O/A ratio of 5. A series of extraction-stripping processes of up to 5 cycles indicated a possible recirculation of regenerated solvent without loss of performance. Simulated experiments in continuous modes suggest that phosphonium-based ionic liquid such as Cyphos IL 101 can be advantageously used as extractant to recover individually Pd, Pt and Rh from acidic chloride feed solutions as those encountered in the PGM's recycling industry.

Performance of fed-batch acetone–butanol–ethanol (ABE) fermentation coupled with the integrated in situ extraction-gas stripping process and the fractional condensation

Abstract: In this study, fed-batch acetone–butanol–ethanol (ABE) fermentation was coupled with the integrated in situ extraction-gas stripping process. The total glucose consumptions were 255 and 310 g/L at the gas flow rates of 0.5 and 1.0 liter per minute (lpm), respectively. The ABE productivity and yield were 0.65 g/L/h and 0.43 g-solvent/g-glucose at the gas flow rates of 0.5 lpm. When the gas flow rates increased from 0.5 to 1.0 lpm, the ABE productivity and yield became 0.69 g/L/h and 0.48 g-solvent/g-glucose, respectively. The fractional condensation was operated by using two different cold traps where temperatures for the first and second one were 2 and −196°C, respectively. It was found that 71–81 and 64–73% of total stripped water was condensed in the 2 °C cold trap at gas flow rates of 0.5 and 1.0 lpm, respectively. Therefore, high ABE concentrations of 360–460 g/L were found in the second cold trap. The overall separation factor for butanol was calculated to be up to 34 where the raffinate solution is the fermentation broth and the extract solution is the condensate in the −196 °C cold trap.

Separation and recovery of sulfuric acid from acidic vanadium leaching solution of stone coal via solvent extraction

Abstract: The separation and recovery of sulfuric acid from an acidic leaching solution of stone coal containing 110 g/L of H2SO4 and 1.98 g/L of vanadium and other metal ions with the use of TEHA was investigated. Vanadium valence has a significant effect on the separation of sulfuric acid and vanadium because of the speciation of the anion VO2SO4− of V(V) in the solution. V(IV) almost has no effect on sulfuric acid separation from vanadium because V(IV) exists as VO2+ in the acidic leaching solution, and the influence of vanadium on sulfuric acid recovery can be decreased by reducing V(V) to V(IV) with Na2SO3. Acid extraction rate increases with an increase in TEHA concentration and O/A phase ratio but decreases with an increase in temperature. Under optimized conditions, sulfuric acid extraction capacity is 86.25 g/L of sulfuric acid with 40% TEHA and a phase ratio (O/A) of 2:1 in a 10 min phase contact at 25 °C. The raffinate containing only 12.74 g/L of sulfuric acid can be directly used for vanadium extraction. Approximately 99% of sulfuric acid could be stripped with hot water at 65 °C and an O/A ratio of 1/3 in a three-stage extraction process.

Selective recovery of Fe(III), Pd(II), Pt(IV), Rh(III) and Ce(III) from simulated leach liquors of spent automobile catalyst by solvent extraction and cementation

Abstract: A hydrometallurical process was developed to recover Fe(III), Pd(II), Pt(IV), Rh(III) and Ce(III) from the leach liquor of spent automobile catalysts. Fe(III) was first separated by extraction with tri-butyl-phosphate (TBP). Extraction of the raffinate with tri-isooctylamine (Alamine 308) led to co-extraction of Pd(II) and Pt(IV). They were separately stripped from the loaded Alamine 308 by using a mixture of HCl and thiourea with different concentration. After the recovery of HCl in the raffinate by extraction with tri-2-ethylhexyl amine (TEHA), Rh(III) was recovered by cementation with zinc metal powder. A process flow sheet with the corresponding McCabe-Thiele plots for extraction and stripping was proposed.

Solubility of γ-oryzanol in supercritical carbon dioxide and extraction from rice bran

Abstract: The γ-oryzanol is a complex mixture of triterpenic alcohols with ferulic acid esters of phytosterols, being an important nutraceutical in rice bran. In order to assess the ability of the supercritical carbon dioxide (scCO2) to extract γ-oryzanol from rice bran, the solubility of γ-oryzanol in scCO2 was measured at 40 °C, 60 °C, and 80 °C, and 200, 300, and 400 bar. A fractional extraction at 60 °C and 400 bar from rice bran containing 22.2% of oil with 1.55% γ-oryzanol was also performed. The mean solubility values ranged from 0.13 to 1.57 g γ-oryzanol/kg CO2, and a crossover pressure (CP) was observed at 300 bar. Below of the crossover pressure, the solubility decreased with increasing temperature and above, there is solubility increase with increasing temperature. Although Chrastil equation parameters have been correlated to experimental data, a high mean deviation of 9.0% was observed because it is a mixture of compounds. The presence of oil lowers the solubility of γ-oryzanol, which is the case of extraction from bran oil, showing that the nutraceutical is more concentrated at the final oil fraction or in the raffinate fractions.

Coupling method of catalytic cracking gasoline desulfurization

Abstract: The invention provides a coupling method of catalytic cracking gasoline desulfurization. The coupling method comprises the following steps: cutting gasoline raw materials into light fractions, medium fractions and heavy fractions; carrying out extractive distillation on the medium fractions by an organic solvent to obtain olefin-contained raffinate and extracts which contain sulfide and arene; separating the organic solvent in the extracts to obtain extraction oil; carrying out selective hydrodesulfurization on the extraction oil and the heavy fractions to obtain the desulfurization heavy fractions; mixing the light fractions, the raffinate and the desulfurization heavy fractions to obtain desulfurization gasoline, wherein the cutting temperature of the light fractions and the medium fractions is 35 to 60DEG C, and the cutting temperature of the medium fractions and the heavy fractions is 140 to 160DEG C. According to the coupling method of the gasoline desulfurization, the octane value loss of a gasoline product can be obviously reduced, and desulfurization load is drastically lowered while deep desulfurization is realized. The yield of the product is greater than 95%.

Method for recycling copper, zinc, cobalt and nickel from various kinds of nonferrous metal containing waste

Abstract: The invention discloses a method for recycling copper, zinc, cobalt and nickel from various kinds of nonferrous metal containing waste The method comprises the steps that nonferrous metal containing dead catalysts, waste battery materials and other waste raw materials are subjected to leaching dissolution by adding acid and an oxidizing agent, a solution containing nickel, cobalt, copper and zinc is subjected to copper extraction after filter pressing, and reverse extraction is carried out on the copper solution for electro deposited copper production; and P204 extraction is carried out after the raffinate is subjected to deironing treatment, reverse extraction galvanizing zinc is obtained, a zinc carbonate product is obtained through settlement and roughening, P507 nickel and cobalt separation is carried out on the raffinate, and a cobalt salt solution and a nickel salt solution are obtained and used for producing cobalt sulphate, nickel carbonate, electrolytic nickel and other products Leaching residues and deironining slag obtained after filter pressing are dissolved and enter a waste slag removal treatment workshop for sintering treatment

Enrichment of copper and recycling of cyanide from copper–cyanide waste by solvent extraction

Abstract: The enrichment of copper from copper–cyanide wastewater by solvent extraction was investigated using a quaternary ammonium salt as an extractant. The influences of important parameters, e.g., organic-phase components, aqueous pH values, temperature, inorganic anion impurities, CN/Cu molar ratio, and stripping reagents, were examined systematically, and the optimal conditions were determined. The results indicated that copper was effectively concentrated from low-concentration solutions using Aliquat 336 and that the extraction efficiency increased linearly with increasing temperature. The aqueous pH value and concentrations of inorganic anion impurities only weakly affected the extraction process when varied in appropriate ranges. The CN/Cu molar ratio affected the extraction efficiency by changing the distribution of copper–cyanide complexes. The difference in gold leaching efficiency between using raffinate and fresh water was negligible.

Reactive extraction of amino acids mixture in hydrolysate from cottonseed meal with di(2‐ethylhexyl) phosphoric acid

Abstract: BACKGROUND In recent years there has been a noticeable growth of amino acid utilization throughout the world. How to separate and purify amino acids from fermentation broths or protein hydrolysates in an effective and low cost way is increasingly becoming an urgent problem. The utilization of solvent extraction technology for amino acids separation offers one solution. RESULTS Extractions of individual amino acids in aqueous solution with di(2-ethyl-hexyl)phosphoric acid (D2EPHA) are dominated by aqueous pH and their hydrophobicity. The degree of extraction of amino acids increases with increasing pH (1.0

The solvent extraction of Am(VI) using centrifugal contactors

Abstract: An engineering-scale centrifugal contactor test bed was built at Idaho National Laboratory to perform solvent extraction testing for the partitioning of hexavalent americium. The raffinate simulant feed was spiked with 243Am and 139Ce and treated with sodium bismuthate to oxidize americium to Am(VI), filtered and contacted with 1 M DAAP/dodecane using centrifugal contactors. Extraction efficiency comparable to batch contacts was obtained, indicating for the first time that Am(VI) can be maintained under process conditions. Contrary to expectations, stripping was not as effective as expected. However, this result may actually be advantageous to process design, since a scrub step, previously thought to be impossible due to rapid Am(VI) reduction, may now be considered for future flowsheet tests.

Method for purifying cannabinoid compounds

Abstract: The present invention relates to methods for purifying one or two cannabinoid compounds using simulated moving bed chromatography, wherein the cannabinoid compound(s) is/are obtained in the extract and/or the raffinate with the total amount of isomeric impurities being below detection level. In particular, the present invention relates to methods for the purification of cannabidiol, trans-(-)-delta-9-tetrahydrocannabinol, cannabidivarin, trans-(-)-delta-9-tetrahydrocannabivarin and cannabigerol which have been obtained by enantiopure synthesis.

Method for recycling cobalt and lithium from waste lithium ion battery material

Abstract: The invention discloses a method for recycling cobalt and lithium from a waste lithium ion battery material. The method mainly comprises discharging of the waste lithium ion battery material, high-temperature roasting, leaching through sulfuric acid and sodium thiosulfate under the ultrasonic condition, precipitating and impurity removal of sodium sulphide, using Cyanex272 as an extraction agent to extract cobalt, using hydrochloric acid for reextraction of the cobalt, and leading lithium-contained extraction raffinate into CO2 gas to be precipitated to obtain lithium carbonate; and by the adoption of the method, the process is simple, cobalt and lithium are high in recycling rate, and the recycling rate of the cobalt in the waste lithium ion battery material and the recycling rate of the lithium in the waste lithium ion battery material are both above 98.5%.

Study on enantioseparation of α-cyclopentyl-mandelic acid enantiomers using continuous liquid-liquid extraction in centrifugal contactor separators: Experiments and modeling

Abstract: Multistage enantioselective liquid-liquid extraction (ELLE) of α­-cyclopentyl-mandelic acid (α-CPMA) enantiomers using hydroxyethyl-β-cyclodextrin (HE-β-CD) as extractant was studied in a cascade of centrifugal contactor separators (CCSs). Performance of the separation process was evaluated by enantiomeric excess (ee) and yield (Y). A multistage equilibrium model was established to predict and optimize the process. The influence of important factors on the multistage separation process, including the extract phase/washing phase ratio (W/O), the concentration of chiral selector, and the pH value of aqueous phase were investigated by experiments and modeling. It was found that the experimental results were in good agreement with the model predictions. The optimal conditions for symmetric separation involves a W/O ratio of 0.5, W/F ratio of 6, pH of 2.5, HE-β-CD concentration of 0.05 mol/L at 5 °C, where ee extract , ee raffinate , Y extract and Y raffinate can reach up to 39%, 35%, 65% and 71%, respectively. By modeling and optimization, the minimum number of stages was evaluated at 66 and 84 for ee eq > 97% and ee eq > 99% (ee eq represents equal enantiomeric excess).

Effect of gas oil composition on performance parameters of the extractive desulfurization process

Abstract: Extractive desulfurization of synthetic and actual gas oil with various solvents was carried out to understand the fruitfulness of studies on solvent screening using synthetic carrier phases. Solvent extraction of various model sulfur compounds from two synthetic carrier phases of different composition was carried out using N,N-dimethylformamide (DMF) solvent to illustrate the effect of the sulfur compound molecular structure on its extractability and interaction with the carrier phase composition. Removal of sulfur compounds from the synthetic carrier phase followed the order: BT ≈ DBT > 4-methyl-DBT > 3-methyl BT ≈ 4,6-dimethyl-DBT > 2-N-octylthiophene ≫ 1-dodecanethiol. Thereafter, extraction of actual straight run gas oil (SRGO), cracked gas oil (CGO), and their mixtures was studied using DMF to understand the effect of their composition on extraction performance. Performance parameters such as yield of raffinate, degree of sulfur removal, distribution coefficient, and performance factor were found to be quite different for different gas oil streams. Thereafter, models were developed for correlating performance of extraction in terms of degree of sulfur removal (Dsr), yield (Y) of extracted gas oil with composition of gas oil and operating conditions. A performance factor (Pf,α) (defined as the summation of Dsr and Y with the weight factor (α) to Dsr) model was used to estimate the optimum operating conditions to maximize the extraction performance. Results indicate that the value of the weight factor (α) affects operating conditions, Dsr and Y, significantly and should be chosen with utmost care in light of downstream process capabilities and overall process economics.