COMPLEX SILICATE OF RARE-EARTH ELEMENTS AND METHOD OF ITS PRODUCTION Russian patent published in 2019 - IPC C09K11/55 C09K11/78 C09K11/79 

FIELD: lighting engineering.

SUBSTANCE: invention can be used in ultraviolet range light, X-ray and electron radiation imaging systems. First, three initial solutions I, II, III are prepared. Solution I is prepared by dissolving CaCO₃, La₂O₃ and Eu₂O₃, taken in stoichiometric ratio, in 60–70 % nitric acid. To prepare II SiO₂ solution added to ethyl alcohol, grinded for 2–3 hours, then dry monobasic citric acid is added in amount of 1/3 of weight of SiO₂ and again grinding 1.5–2 hours. To prepare solution III, dry monohydric citric acid is added to aqueous solution of ethyl alcohol at ratio of water: alcohol 1:1. Obtained solutions are mixed and evaporated at 120–140 °C for 2–3 hours. Then heat treated at 200–900 °C at temperature rise rate of 50–55 °C/h. Thermally treated mixture is pressed at pressure of 14–24 MPa with subsequent annealing at 1,350–1,400 °C for 50–60 hours, by pressing at pressure of 9.0–9.5 GPa with simultaneous heating at 1,350–1,450 °C for 5–10 minutes. Obtaining fluorescent white luminophore, which is a rare-earth element silicate of composition Ca₂La_6.8Eu_1.2Si₆O_26-δ, where 0.07≤δ≤0.12.

EFFECT: invention widens the range of luminophors which provide a purely white color of the glow.

2 cl, 2 ex