COMPLEX SILICATE OF RARE-EARTH ELEMENTS AND METHOD OF ITS PRODUCTION

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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 Ca2La6.8Eu1.2Si6O26-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