| 1. |
- Hansson, Niklas, 1992, et al.
(författare)
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Geometrical aspects of alpha dose rates from UO2 based fuels
- 2022
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Ingår i: Radiation Physics and Chemistry. - : Elsevier BV. - 0969-806X .- 1879-0895. ; 199, s. 110336-
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Tidskriftsartikel (refereegranskat)abstract
- Models for calculating dose rates of spherical particles as well as in fuel cracks are important for radionuclide source term estimations. Dose rates from UO2 based fuels were calculated for planar, spherical, and crack geometries. The escape probability for a-particles in spherical UO2 particles was derived as a continuous equation. The dose rate increased with increasing spherical radius due to the decreasing relative volume of the surrounding water layer. The model produced escape probabilities that were closely predicted by the theoretical derivation. It was shown that the dose rate in water filled fuel cracks with width smaller than the range of an alpha-particle led to dissolution rates that were lower per unit surface area.
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| 2. |
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| 3. |
- Ramebäck, Henrik, 1967, et al.
(författare)
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A Monte Carlo method for calculation of the characteristic limits decision threshold and detection limit in low-level radioactivity measurements
- 2021
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 178
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Tidskriftsartikel (refereegranskat)abstract
- In this study, calculation of decision threshold and detection limit expressed in counts for low-level radioactivity measurements were evaluated and compared to a Monte Carlo method for the case of paired Poisson-distributed observations, i.e. for discrete variables. The calculated characteristic limits obtained from Monte Carlo calculations were compared with analytical expressions given in literature. The results in this study show that the equations given by Currie are in good agreement with the results from the Monte Carlo calculations simulating nuclear counting applications with a low number of observed counts. An exception is observed for a background corresponding to zero counts. This study also shows that at a low number of counts, the specific boundary conditions of the interval that represents counts corresponding to the presence of the analyte (>or ≥), have an impact on the false positives and negatives rates as defined by the parameters α and β.
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| 4. |
- Ramebäck, Henrik, 1967, et al.
(författare)
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Calculation of decision threshold and detection limit in radiometric measurements using a Monte Carlo Method
- 2020
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 156
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Tidskriftsartikel (refereegranskat)abstract
- Calculation of the decision threshold and detection limit of a measurement, or measurement method, are crucial in order to decide if an analyte is present or not and with what confidence it can be quantified. That decision is important in view of possible actions if something would be detected. In this work, a method for calculating these limits using a Monte Carlo method is presented. In the Monte Carlo method any a priori distribution (e.g. normal distribution, rectangular distribution, triangular distribution) of an input quantity can be selected. Differences between the Monte Carlo calculated characteristic limits and the ones calculated according to ISO 11929:2010 is presented. Moreover, suggestions how to calculate the detection limit when it can not be calculated according to the ISO 11929:2010 are given.
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| 5. |
- Vieceli, Nathalia Cristine, 1989, et al.
(författare)
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Recycling of Li-Ion Batteries from Industrial Processing: Upscaled Hydrometallurgical Treatment and Recovery of High Purity Manganese by Solvent Extraction
- 2023
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Ingår i: Solvent Extraction and Ion Exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 41:2, s. 205-220
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Tidskriftsartikel (refereegranskat)abstract
- Manganese plays a central role in lithium-ion batteries (LIBs) but its recycling is rarely addressed when compared to other valuable metals present in LIBs, such as Co and Ni. Thus, the main goal of this work was to study and achieve the separation of Mn from Co and Ni by solvent extraction from a leachate obtained from LIBs using hydrochloric acid in an upscaled reactor, which is an innovative aspect of this work. The results confirmed the high selectivity of D2EHPA towards Mn, which could be completely extracted in two stages (0.5 M D2EHPA at pH 2.5). The main co-extracted metals were Al, Cu and Co, but with lower concentrations than Mn. The behavior of minor impurities such as Zn and Mg was also monitored. Scrubbing using manganese chloride was crucial to remove impurities from the loaded organic and prevent their presence in the stripping product, and high O:A ratios negatively affected the scrubbing efficiency. Keeping the concentration of HCl up to 0.5 M in the stripping stage helped to limit the stripping of impurities. Manganese oxide was precipitated as a product with 99.5% purity (with traces of Zn, Cu and Co), which could be reused in the battery value chain.
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| 6. |
- Vieceli, Nathalia Cristine, 1989, et al.
(författare)
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Solvent extraction of cobalt from spent lithium-ion batteries: Dynamic optimization of the number of extraction stages using factorial design of experiments and response surface methodology
- 2023
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Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 307
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Tidskriftsartikel (refereegranskat)abstract
- The optimization of lithium-ion batteries (LiBs) recycling is crucial not only from a waste management perspective but also to decrease the dependence on imports of critical raw materials. In addition, the diversification of the recycling technologies is very important for better flexibility of the market. This study aims at investigating the recovery of Co from spent LiBs using solvent extraction from a real chloride-based solution obtained after the removal of Mn, which is very rarely reported. Cyanex 272 was used as the extractant and the effect of several variables on the extraction efficiency was considered to model and optimize the separation of Co and Ni. The number of extraction stages directly affects not only the process efficiency but also its cost. Thus, in this work, a novel approach was developed to assist in the selection of the number of extraction stages using a dynamic method based on the factorial design of experiments and response surface methodology combined with the Kremseŕs Equation. This method can assist the process design, decrease the overall cost of the operation, and optimize the separation of Co and Ni in a reduced number of extraction stages. The concentration of Co and Ni in the feed solutions is ∼ 8.3 g/L and 1.9 g/L, respectively. Based on the results, 98% extraction efficiency for Co can be achieved in 1 to 2 extraction stages with low co-extraction of Ni (<5%) when using 0.6–0.8 M Cyanex 272, O:A ratio below 1 and pH ∼ 5, but several combinations of conditions could provide similar results.
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| 7. |
- Agrawal, Munmun, et al.
(författare)
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Global market trends of tantalum and recycling methods from Waste Tantalum Capacitors: A review
- 2021
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Ingår i: Sustainable Materials and Technologies. - : Elsevier BV. - 2214-9937. ; 29
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Forskningsöversikt (refereegranskat)abstract
- The rapid digitalization of the world, technological up-gradation, and shorten life cycle of electronic gadgets leading to the generation of an enormous amount of waste tantalum capacitors (WTCs) rich in tantalum every year. The need of the hour is to develop an effective way to recycle tantalum from these waste scraps considering the scarcity of tantalum, environmental impacts, resource and energy utilization, and lower recycling rates. In this paper, various existing methods of recovery of metallic tantalum from WTCs have been extensively reviewed. Processes have been examined in light of recovery efficiency, purity of the resultant product, process complexity, and limitations. The bottleneck in the recovery of tantalum from WTCs is the presence of tightly covered mold resin over the surface of the tantalum anode. Various researchers have recovered Ta with varying degrees of success. Pyrolysis, followed by chloride metallurgy, has been proven to be an effective technology on account of its high removal rate, resource and energy utilization, and lesser environmental impacts. This article also explores the global scenario of tantalum. Overall this review provides a foundation to understand the potential barrier and various opportunities associated with the recovery of tantalum from WTCs.
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| 8. |
- Armand, Michel, et al.
(författare)
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Lithium-ion batteries – Current state of the art and anticipated developments
- 2020
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 479
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Tidskriftsartikel (refereegranskat)abstract
- Lithium-ion batteries are the state-of-the-art electrochemical energy storage technology for mobile electronic devices and electric vehicles. Accordingly, they have attracted a continuously increasing interest in academia and industry, which has led to a steady improvement in energy and power density, while the costs have decreased at even faster pace. Important questions, though, are, to which extent and how (fast) the performance can be further improved, and how the envisioned goal of truly sustainable energy storage can be realized. Herein, we combine a comprehensive review of important findings and developments in this field that have enabled their tremendous success with an overview of very recent trends concerning the active materials for the negative and positive electrode as well as the electrolyte. Moreover, we critically discuss current and anticipated electrode fabrication processes, as well as an essential prerequisite for “greener” batteries – the recycling. In each of these chapters, we eventually summarize important remaining challenges and propose potential directions for further improvement. Finally, we conclude this article with a brief summary of the performance metrics of commercial lithium-ion cells and a few thoughts towards the future development of this technology including several key performance indicators for the mid-term to long-term future.
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| 9. |
- Babain, V., et al.
(författare)
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Fluorinated Diluents- A Review
- 2023
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Ingår i: Solvent Extraction and Ion Exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 41:3, s. 253-291
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Forskningsöversikt (refereegranskat)abstract
- The history of the development of fluorinated compounds as potential diluents in solvent extraction processes is described. Fluorinated diluents were first investigated in the former Soviet Union and later in the United States and Europe. Fluorinated diluents represent a class of compounds that can be used as primary diluents or as phase modifiers. They are of particular utility when extractant solubility is limited in traditional hydrocarbon diluents and a polar diluent is needed. The chemical and physical characterisitics of fluorinated diluents are provided for a broad range of compounds. Other properties such as toxidcity and resistance to radiolysis are described. Fluorinated compounds have been studied for over 40 years and have been used at industrial scale as a primary diluent for cesium and strontium extraction in Russia and as a phase modifer for an insustrial-scale cesium extraction process in the United States. The advantages and disadvantages of traditional hydrocarbon diluents are compared with chlorinated diluents, chlorinated and fluorinated diluents, and a number of different types of fluorinated diluents. Developing trends for teh use of fluorinated diluents in solvent extraction processes are discussed. This article should provide assistance to researchers investigating new or improved solvent extraction processes where traditional hydrocarbon diluents may not be appropriate.
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| 10. |
- Brown, Paul L., et al.
(författare)
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The aqueous chemistry of radium
- 2022
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Ingår i: Radiochimica Acta. - : Walter de Gruyter GmbH. - 0033-8230 .- 2193-3405. ; 110:6-9, s. 505-513
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Tidskriftsartikel (refereegranskat)abstract
- Available literature data on the aqueous chemistry of radium are compiled. There are limited available experimental data and a significant portion of the data has been estimated using electrostatic techniques, typically based on the corresponding data of barium. The available data are compared with the corresponding data of barium (and strontium) and a methodology for estimating additional radium thermochemical data is described.
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