DEVELOPMENT OF A METHODOLOGY FOR THE SEPARATION OF EUROPIUM AND SAMARIUM FROM A MIXTURE OF RARE EARTH OXIDES BY ELECTROREDUCTION/PRECIPITATION / "Desenvolvimento de uma metodologia para a separação de Samário e Európio a partir de mistura de óxidos de Terras Raras por redução eletroquímica/ precipitação"

AUTOR(ES)

Vera Chepcanoff

DATA DE PUBLICAÇÃO

2006

RESUMO

The rare earths (RE) were first used in 1903, when Welsbach developed a lighter that is still used today. Nowadays, the RE are employed in many different fields, as in the production of super-alloys , as catalysts for petroleum industry, in the manufacture of non-ferrous alloys, color television tubes, x-ray screens, special glasses, ceramics, computer industries, nuclear medicine, lasers, pigments, etc., moving, in the last decade , a market of US$ 2 billions per year. Due to their similar properties, the RE elements are very difficult to separate, requiring complex processes, what make the products very expensive. Elements like Eu and Sm, which contents in the minerals are low (0.05% and 2.0%, respectively, in monazite) are extremely expensive, but their field of application justifies the research for looking for other processes, more simple and/or more effective. Trivalent state is a characteristic of all RE, but some of them presents oxidation state +2, like Ce, Eu, Sm and Yb. In the case of Eu and Sm, the focus of the present work, the divalent state is achieved by electro-reduction in the potentials –0.65 and –1.55 (SCE), respectively. This makes possible the separation of these elements from the other rare earths and from each other. Thus, making use of this characteristic, a process for the individual separation of Eu and Sm in (NH4)2SO4 solution by electro-reduction/precipitation is proposed, where Sm is first separated from the solution as sulfate, and Eu, that remains in the solution, is precipitated after the decrease of temperature and potential applied. The process developed from a synthetic Eu and Sm solution was applied to a mixture of semi-heavy RE oxide, produced at IPEN-CNEN/SP, obtaining the separation of Sm. This product was analyzed by spectrophotometry, showing high purity.

ASSUNTO(S)

separation processes rare lands electrochemical terras raras eletroquímica processos de separação

Documentos Relacionados

• Development, microstructural and mechanical caracterization of SiC ceramics with alumina and rare earth oxides additions
• Desenvolvimento, caracterização microestrutural e mecânica de cerâmicas de SiC aditivadas com alumina e óxidos de terras raras
• Desenvolvimento, caracterização microestrutural e mecânica de cerâmicas de SiC aditivadas com alumina e óxidos de terras raras
• SIMULAÇÕES ATOMÍSTICAS EM TRIFLUORETOS (REF3) E ÓXIDOS METÁLICOS MISTOS (RE(TiTa)O6) DE TERRAS-RARAS
• Preparation and characterization of PbTi0(3) ceramics modified by a natural mixture of rare earth oxides of xenotime