Rare-earth borate and its precursor, preparation processes and use of borate as luminophore
AssigneeRhodia Chimie
InventorsDenis Huguenin, Pierre Macaudiere
Life of this patent
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Abstract
The present invention relates to a rare-earth borate, to a precursor thereof, to processes for their preparation and to the use of this borate as a luminophore. The rare-earth borate and the precursor thereof are characterized in that they are in the form of cubic, parallelepipedal or spherical particles and in that they have a dispersion index of not more than 0.8. According to one embodiment of the invention, the borate is a red luminophore. The process for the preparation of the precursor is characterized in that a rare-earth carbonate or hydroxycarbonate is reacted with boric acid, the reaction medium being in the form of an aqueous solution. The borate is obtained by calcination of the precursor.
Claims13
Yttrium boron hydroxycarbonate or yttrium gadolinium boron hydroxycarbonate further comprising terbium, having luminescent properties.
Process for the preparation of a rare-earth boron hydroxycarbonate, comprising reacting a rare-earth carbonate or hydroxycarbonate with boric acid in a reaction medium in the form of an aqueous solution, the reaction is carried out while removing CO2 formed during the reaction.
Process for the preparation of a rare-earth boron hydroxycarbonate, comprising reacting a rare-earth carbonate or hydroxycarbonate with boric acid in a reaction medium comprising mother liquors of the rare-earth carbonate or hydroxycarbonate.
Process for the preparation of a rare-earth borate, comprising reacting a rare-earth carbonate or hydroxycarbonate with boric acid in a reaction medium in the form of an aqueous solution to form a precipitate, the reaction is carried out while removing CO2 formed during the reaction, and calcining the precipitate.
Process for the preparation of a rare-earth borate, comprising reacting a rare-earth carbonate or hydroxycarbonate with boric acid in a reaction medium comprising mother liquors of the rare-earth carbonate or hydroxycarbonate to form a precipitate, and calcining the precipitate.
Dependencies are inferred from the claim text.