ANTONIO ALVES DE FREITAS
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Artigo IPEN-doc 16136 Studies on the separation of 99Mo from nitric acid medium by alumina2010 - YAMAURA, M.; FREITAS, A.A.; YAMAMURA, A.P.G.; TANAKA, R.M.N.; FORBICINI, C.A.L.G. de O.; CAMILO, R.L.; ARAUJO, I.C.99mTc, the product of radioactive decay of 99Mo, is one of the most used radioisotopes in nuclear medicine. The 99Mo is produced mainly by fission of 235U targets HEU or LEU. After the dissolution of uranium targets, chemical process for the separation and purification is performed in chromatographic columns. This work presents a study on the behavior of 99Mo removal by adsorption on acid and neutral alumina from nitric acid, which is the dissolution reagent for LEU targets in the Modified Cintichem Process. Adsorption kinetics in solution of HNO3 and the influence of pH were investigated. It was also evaluated the adsorption of 99Mo from nitric solutions containing uranyl ions.Artigo IPEN-doc 18753 Efeito do pH e concentração na adsorção de Mo nas aluminas2012 - YAMAURA, M.; DAMASCENO, M.; FREITAS, A.A.; EGUTE, N.S.; HOLLAND, H.Artigo IPEN-doc 10778 Estudo do tratamento de um residuo de torio e terras raras por cromatografia de extracao2005 - ZINI, J.; ABRAO, A.; CARVALHO, F.M.S.; FREITAS, A.A.; SCAPIN, M.A.Artigo IPEN-doc 08841 Transformacao via peroxido de um hidroxido bruto de torio em nitrato para camisas de lampiao2002 - FREITAS, A.A.; CARVALHO, F.M.S.; FERREIRA, J.C.; ABRAO, A.Artigo IPEN-doc 19507 Review of brazilian activities related to the thorium fuel cycle and production of thorium compounds at IPEN-CNEN/SP2013 - LAINETTI, PAULO E.O.; FREITAS, ANTONIO A.; MINDRISZ, ANA C.Artigo IPEN-doc 16904 Uranium recovery from waste of the nuclear fuel cycle plants at IPEN-CNEN/SP2011 - FREITAS, ANTONIO A.; FERREIRA, JOAO C.; ZINI, JOSIANE; SCAPIN, MARCOS A.; CARVALHO, FATIMA M.S. deArtigo IPEN-doc 16885 Molybdenum adsorption by alumina and dowex 1x8 resin for the separation and purification process of fission sup(99)Mo2011 - YAMAURA, M.; DAMASCENO, M.O.; FREITAS, A.A.; CAMILO, R.L.; ARAUJO, I.C.; FORBICINI, C.A.L.G. de O.Artigo IPEN-doc 13274 Recuperacao de chumbo-208 radiogenico de residuo contendo torio e terras raras2008 - FERREIRA, J.C.; FREITAS, A.A. de; SENEDA, J.A.; CARVALHO, F.M.S. de; ABRAO, A.Artigo IPEN-doc 08294 Preparation of highly pure thorium nitrate via thorium sulfate and thorium peroxide2000 - ABRAO, A.; FREITAS, A.A.; CARVALHO, F.M.S.A simple alternative and selective method has been proposed for the preparation of thorium nitrate using as raw material a hydrated crystalline technical grade thorium sulfate. This salt was produced industrially [1] from the alkaline chemical processing of monazite sand in S. Paulo. From a crude thorium hydroxide as the raw material containing uranium and rare earth elements was prepared a technical grade thorium sulfate [Th(SO ) .9H O]. A typical analysis of this salt had shown the following composition: ThO 47–53%, R O (rare 42 2 2 23 earth oxides) 0.5–0.9%, and UO 0.01% and minor amounts of iron, titanium, phosphorus, and silicon oxides. The thorium sulfate is 3 dissolved into water and the thorium peroxide is precipitated from acidic medium by addition of hydrogen peroxide. The thorium peroxide is filtered, washed and finally dissolved with nitric acid. Samples of the thorium peroxide were dried and fired to ThO and aliquot of the 2 thorium nitrate solution was evaporated to dryness and calcined to obtain the ThO . Both ThO have high purity (.99.5%). The content 2 2 of total rare earth elements is very low (0.23% as oxide). Uranium was not detected. The great majority of the RE is precipitated and recovered from the filtrate by oxalic acid.Artigo IPEN-doc 17133 Separation of fission sup(99)Mo by alpha-benzoin oxime precipitation in nitric medium2011 - YAMAURA, MITIKO; FREITAS, ANTONIO A.; EGUTE, NAYARA dos S.; CAMILO, RUTH L.; ARAUJO, IZILDA C.; FORBICINI, CHRISTINA A.L.G. de O.