SORAYA MARIA RIZZO DA ROCHA

SORAYA MARIA RIZZO DA ROCHA

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Obtaining pure praseodymium acetate to use in researches and development
2010 - QUEIROZ, CARLOS A. da S.; ROCHA, SORAYA M.R. da; PEDREIRA, WALTER R.; SENEDA, JOSE A.; LOBO, RAQUEL M.; S. FILHO, WALTER
This paper presents a simple and economical procedure to obtain high purity praseodymium acetate. The raw material in the form of mixed rare earths carbonate comes from a industrial separation of rare earths, thorium and uranium in the brasilian monazite. It is used the tecnique of strong cation exchange resin, proper to water treatment, to the praseodymium's fractionation and it is achieved a purity of 99.9% in Pr6O11 and yield greater than or equal 60%, with the elution of rare earths by EDTA solution in pH controlled. The complex of EDTA-praseodymium is transformed in praseodymium oxide, subsequently the oxide is dissolved in acetic acid to obtain the praseodymium acetate. The molecular absorption spectrophotometry tecnique is used to monitoring the praseodymium content during the process and mass spectrometry to certification the purity of the praseodymium acetate. The typical praseodymium acetate obtained presents the followings contaminants in micrograms per gram: Sc(18.20±0.22); Y (20.20 ± 0.20); La (6.75 ± 0.81); Ce (26.10 ± 0.70); Nd (3.31 ± 0.63); Sm (18.30 ± 0.80); Eu (17.00 ± 0.90); Gd (19.40 ± 0.40); Tb (16.30 ± 0.50); Dy (16.90 ± 0.50), Ho(17.90 ± 0.10); Er (18.40 ± 0.70); Tm (16.90 ± 0.10); Yb (17.60 ± 0.60); Lu (17.70 ± 0.50). The high purity praseodymium acetate comes being applied, replacing the imported product, in research and development area on rare earth catalysts.
Resurgence of an old test for identification of lanthanum
2001 - ABRAO, A.; RIZZO, S.M.; QUEIROZ, C.A.S.
Advanced mass spectrometric applied to determinated of composition in lead (Pb-208) from residues of thorium facilities
2007 - SENEDA, JOSE A.; QUEIROZ, CARLOS A. da S.; RIZZO, SORAYA M. da R.; DIAS, MAURO S.; KAKAZU, MAURICIO H.; ABRAO, ALCIDIO
Characterization of lanthanium oxide on the thermal stability of gamma alumina catalyst supports
2007 - ROCHA, S.M.R.; VASCONCELLOS, M.E. de; QUEIROZ, C.A.S.; FORBICINI, C.A.L.G.O.; SENEDA, J.A.; PEDREIRA, W.R.
Obtencao experimental de acetato de praseodimio de alta pureza a partir de carbonatos mistos de terras raras
2010 - QUEIROZ, C.A. da S.; ROCHA, S.M.R. da; PEDREIRA, W.R.; SENEDA, J.A.; LOBO, R.M.; FILHO, W.S.
Sintese e caracterizacao de precursores a base de lantanio para aplicacao em catalisadores
2002 - ROCHA, S.M.R.; QUEIROZ, C.A.S.; ABRAO, A.
Produção de lantânio de alta pureza para aplicação em P&D
2002 - VASCONCELLOS, M.E.; QUEIROZ, C.A.S.; ROCHA, S.M.R.; SENEDA, J.A.; PEDREIRA FILHO, W.R.; SARKIS, J.E.S.; FORBICINI, C.A.L.G.O.; ABRAO, A.
Synthesis and characterization of lanthanum acetate for application as a catalyst
2001 - ROCHA, S.M.R.; QUEIROZ, C.A.S.; ABRAO, A.
High purity neodymium acetate from mixed rare earth carbonates
2011 - QUEIROZ, CARLOS A. da S.; ROCHA, SORAYA M.R. da; PEDREIRA, WALTER dos R.; VASCONCELLOS, MARI E. de; LOBO, RAQUEL M.; SENEDA, JOSE A.
Synthesis of advanced chemically bonded ceramics for solidification of radioactive wastes
2011 - SENEDA, JOSE A.; DELLAMANO, JOSE C.; QUEIROZ, CARLOS A.S.; GENOVA, LUIS A.; ROCHA, SORAYA M.R. da; VICENTE, ROBERTO