MARIANA NOVAIS DE ANDRADE
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Artigo IPEN-doc 28292 Use of the ion exchange technique for purification of lithium carbonate for nuclear industry2021 - ANDRADE, MARIANA N.; OLIVEIRA, GLAUCIA C.; CONTRIM, MARYCEL E.B.; SENEDA, JOSE A.; BUSTILLOS, OSCAR V.Artigo IPEN-doc 26319 Purification of lithium carbonate by ion-exchange processes for application in nuclear reactors2019 - ANDRADE, MARIANA N.; OLIVEIRA, GLAUCIA A.C.; PIRANI, DEBORA A.; COUTINHO, JOAO F.; BERGAMASCHI, VANDERLEI S.; SENEDA, JOSE A.; BUSTILLOS, JOSE O.V.Lithium Compounds have applications in strategic areas for intern consumption of a country as well as international commerce. In nuclear industry, the lithium is used for the cooling of PWR reactors as a pH stabilizer. Based on this assumption, the generation of knowledge to master the processing cycle of these compounds is essential. The high degree of purity of lithium compounds is determinant to have success in these applications. Lithium hydroxide LiOH and lithium carbonate Li2CO3 are the main forms in which lithium is used industrially. To improve the quality of the starting product, purifying process were used until obtaining an adequate purity level of raw material (> 99%). The present work aims to make feasible a purification of Li2CO3 through ion-exchange chromatography from a 98.5% purity compound. The impurities present in higher content are sodium and calcium. To separate these two elements from lithium or at least to lower their concentrations, a column with cationic resin was used to fix lithium. The determination of lithium, sodium and calcium contents in the solutions was performed by inductively coupled plasma optical emission spectrometry, ICP-OES. The experiments performed to evaluate the best lithium purification condition were based on the variation of the main operational parameters: pH, flow and elution solution. The results indicate increased purity from the application of ion exchange operations obtaining a suitable condition for nuclear uses.Artigo IPEN-doc 26193 Uranium removal from contaminated water by ion exchange resins2019 - PIRANI, DEBORA A.; COTRIM, MARYCEL E.B.; OLIVEIRA, GLAUCIA A.C. de; ANDRADE, MARIANA N. de; FURUSAWA, HELIO A.In the nuclear fuel cycle, uranium containing liquid wastes can be produced in large quantities. There are several possible operations to separate this element from an aqueous solution. The classic examples are separation by solvent extraction and by precipitation when uranium is present in high concentrated solutions. In those cases where the element is present in concentrations as low as 100-200 μg mL-1, ion exchange technique can be very helpful to bring the uranium concentration to less than 10-20 ug mL-1. The synthetic resins used in ion exchange processes effectively remove metals from contaminated liquid wastes. This work intends to remove uranium from aqueous solutions by ion exchange technique. A column (10 cm in height and 1 cm in diameter) was used with 30 ml of dry Dowex 1-X8 strong anionic resin to fix and remove uranium from the solution. The solution with 155 mg.L-1 of uranium was percolated through the column with a flow of 4.0 mL.min-1. Resin was conditioned at pH = 7. The determination of the uranium contents was performed by Optical Emission Spectrometry with Argon Plasma Source (ICP-OES). The main operational parameters, such as pH, flow and column height, were evaluated to determine the best operating condition of the system. The results indicated approximately 99.9% removal of uranium from the application of the ion exchange technique. The percentage of removal allows the effluent to be properly disposed of in a sewage collection system in accordance with the regulations in force in the country.