METHOD OF OBTAINING LITHIUM NIOBATE CHARGE FOR GROWING MONOCRYSTALS Russian patent published in 2013 - IPC C01G33/00 C01D15/00 

FIELD: chemistry.

SUBSTANCE: invention relates to method of obtaining compounds of rare elements, in particular charge of lithium niobate, which can be applied for growing monocrystals by method of extraction from melt. Magnesium oxide is introduced into highly pure niobium-containing solution in quantity, which ensures its content 3-6 mol % in charge of lithium niobate, according to ratio Nb₂O₅:MgO=1:0.0091-0.0186. Ammonia solution is added into obtained solution until pH 12-13 is obtained. Hydroxide sediment is separated and washed with deionised water in ratio S:L=1:2-5 until pH of washing solution is 7-8. Washing hydroxide solution is tempered at temperature 1100-1350°C with formation of alloyed by magnesium powder-like niobium pentaoxide, which is mixed with lithium carbonate in molar ratio 1.04-1.09:1. Mixture of niobium pentaoxide and lithium carbonate is pressed by pressure 5-10 N/cm², and then subjected to thermal processing at temperature 1200-1240°C with obtaining lithium niobate charge. Monocrystals of lithium niobate with improved ferroelectric characteristics are obtained from synthesised charge.

EFFECT: method makes it possible to obtain granulated, alloyed by magnesium homogeneous charge of lithium niobate LiNbO₃:Mg, which has congruous composition and increased bulk weight.

4 cl, 4 ex