Preparation of high purity cerium precursors for use in automotive catalysts
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2018
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BRAZILIAN MRS MEETING, 17th
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Resumo
Starting with a fraction of mixed rare earths chloride with 47% in CeO2 , high pure
cerium oxide and acetate was prepared. The mixed rare earths chloride solution
was treated by fractionated precipitation technique. Cerium (III) was oxidized to
cerium (IV) by addition of hydrogen peroxide. The acidity liberated in the
hydrolytic process was neutralizes with NH3 stream generated by compressed air
injected into the 1M NH4OH solution and bubbled into the rare chlorides solution.
The temperature was maintained at 60oC. After the complete cerium hydroxide
precipitation, it was separated by filtration. This hydroxide precipitate enriched in
cerium (90% in CeO2) was dissolved in hydrochloric acid and the cerium chloride
solution was used as the feeling solution to a strong cationic ion exchanger resin
system. After loading the resin with de cerium, it was rinsed with water and
eluted the ions by complexation with ammonium salt of EDTA adjusted to pH 4,0.
Free EDTA acid was precipitated by addition of chloride acid to the cerium
complex eluted and it was separated by filtration. The ultimate cerium chloride
solution was treated with oxalic acid and the cerium oxalate separated, dried and
fired to cerium oxide. The highly pure cerium oxide prepared (99.9%) was directly
dissolved with hot concentrated acetic acid.The typical cerium acetate obtained
contain the followings contaminants in micrograms per gram: Y(4.1 ), Sc (15.4 ),
La (32.4), Pr (14.6), Nd (6.5), Sm (9.7), Eu (5.3), Gd (9.2), Tb (6.2), Dy (5.4), Ho
(0.08) Er(0.9), Tm (0.2),Yb ( 20.5), Lu (2.3).
Como referenciar
QUEIROZ, CARLOS A. da S. Preparation of high purity cerium precursors for use in automotive catalysts. In: BRAZILIAN MRS MEETING, 17th, September 16-20, 2018, Natal, RN. Abstract... São Carlos: Aptor Software, 2018. p. 1231-1231. Disponível em: http://repositorio.ipen.br/handle/123456789/30328. Acesso em: 19 Apr 2024.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.