CARLOS ALBERTO DA SILVA QUEIROZ

CARLOS ALBERTO DA SILVA QUEIROZ

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Preparation of neodymium acetate for use in nuclear area and nanotechnology
2017 - QUEIROZ, C.A.S.; PEDREIRA FILHO, W.R.; SENEDA, J.A.
Neodymium and its compounds are being increasingly applied in the manufacture of new materials. In nuclear area neodymium isotopes are used in a variety of scientific applications. Nd-142 has been used to produce short-lived Tm and Yb isotopes. Nd-146 has been suggested to produce Pm-147 and Nd-150 has been used to study double beta decay. Due to the several modern applications using nanomaterials, more and more highly rare earth compounds have been demanded. The researches at IPEN uses the experience gained in rare earth separation for the preparation of some pure acetates, purity > 99.9% for application in nanotechnology research. A simple and economical chemical process to obtaining neodymium acetate of high purity is studied. The raw material in the form of mixed rare earths carbonate comes from Brazilian monazite. It is used the technique of strong cationic exchange resin, proper to water treatment, to the neodymium's fractionation and it is achieved a purity of 99.9% in Nd2O3 and yield greater than or equal 80%, with the elution of rare earths by EDTA solution in pH controlled. The complex of EDTA-neodymium is transformed in neodymium oxide, subsequently the oxide is dissolved in acetic acid to obtain the neodymium acetate. The solid salt was characterized via molecular absorption spectrophotometry, mass spectrometry, thermal analysis, chemical analysis and X ray diffraction. In summary the analytical data collected allowed to conclude that the stoichiometric formula for the neodymium acetate prepared is Nd(CH 3COOH)3.1.5H2O.
Conditions for the ion exchange separation of gadolinium and samarium from a mixed rare earths carbomates
1985 - QUEIROZ, CARLOS A. da S.; ABRAO, ALCIDIO
Sintese e caracterizacao de precursores a base de lantanio para aplicacao em catalisadores
2002 - ROCHA, S.M.R.; QUEIROZ, C.A.S.; ABRAO, A.
Synthesis and characterization of lanthanum acetate for application as a catalyst
2001 - ROCHA, S.M.R.; QUEIROZ, C.A.S.; ABRAO, A.
Study on radiogenic lead recovery from residues in thorium facilities using ion exhange anb electrochemical process
2007 - SENEDA, JOSE A.; FORBICINI, CHRISTINA A.L.G. de O.; QUEIROZ, CARLOS A. da S.; VASCONCELLOS, MARI E. de; FORBICINI, SERGIO; RIZZO, SORAYA M. da R.; ABRAO, ALCIDIO
Synthesis and characterization of lanthanum acetate for application as a catalyst
2002 - ROCHA, S.M.R.; QUEIROZ, C.A.S.; ABRAO, A.
Study on radiogenic lead recovery from residues in thorium facilities using ion exchange and electrochemical process
2010 - SENEDA, J.A.; FORBICINI, C.A.L.G. de O.; QUEIROZ, C.A. da S.; VASCONCELLOS, M.E. de; FORBICINI, S.; RIZZO, S.M. da R.; SALVADOR, VERA L.R.; ABRÃO, A.
Brazil has one of the biggest mineral thorium reserves, enabling the use of this material in its nuclear reactors. Consequently, this cycle of the fuel would need an initial purification stage of the natural thorium, generating residues from chemical treatment. This work provides operational parameters for the recovery of existing values in these residues, especially the radiogenic lead, that is a radioisotope of thorium decay chain, using ionic exchange technique associated to the electrochemical one. The treatment by ionic exchange in anionic resin and hydrochloric acid medium, provides about 33.4% of radiogenic lead. At the electrochemical process, lead was reduced to a metal in nitric acid medium, presenting a recovery of 98%. The electrochemical process presents an increase in the cost, nevertheless the technological importance of the radiogenic lead in the production of new elements, besides being a strategic material, justifies its use.