Producing rare earth metal oxide powders, e.g. useful as luminescent or colored pigments or catalys

文件类型：PDF文档
文件大小：560K
Producing a rare earth metal sesquioxide, oxohydroxide or hydroxide powder comprises dissolving nitrate precursors in a polar organic solvent with a boiling point above 200 deg. C in an amount of 10-500 g/l in the presence of water and heating the solution to a temperature above 170 deg. C but below the boiling point of the solvent to precipitate the powder. - Producing a rare earth metal (Ln) sesquioxide, oxohydroxide or hydroxide, optionally mixed or doped with Ln or cerium, or a mixed oxide of formula (I) or (II) in the form of a mono- or polyphase powder containing more than 50 wt.% Ln, or a colloidal suspension thereof, comprises dissolving precursors of Ln and optionally A, at least 50 wt.% of which are Ln nitrates, in a polar organic solvent with a boiling point above 200 deg. C in an amount of 10-500 g/l in the presence of water, heating the solution to a temperature above 170 deg. C but below the boiling point of the solvent to precipitate the powder in the form of nanostructured particles with an average diameter of 20-800 nm, optionally separating and drying the powder and optionally redispersing the powder in a solvent. - LnxA2-x(O)y (I) - LnxA2-x(O)v(OH)z (II) - Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu; - A = a transition metal, B, Al, Si, P or Bi; - x = 0-2; - y = 3-4; - v = 0-4; - z = 0 to 8-2v. - An INDEPENDENT CLAIM is also included for a Ln2O3 powder or a colloidal suspension thereof, optionally mixed or doped with Ln or cerium, comprising nanostructured spherical particles with an average diameter of 20-800 nm.