SYNTHESIS OF X ZEOLITE BASED ON NATURAL MINERAL OF NAKHCHIVAN: THE INFLUENCE OF VARIOUS FACTORS ON THE CRYSTALLIZATION PROCESS

For the first were synthesized of practically important zeolite of X on the basis of natural mineral of Nakhchivan obsidiane volcanic glass. A sample of natural volcanic glass was taken from the peak of Gapydzhik of Ordubad district. The hydrothermal synthesis has been carried out in Morey type autoclaves made up of 45MNFT stainless steel with a volume of 20 cm3 , and with the filling coefficient of F = 0.8. The hydrothermal crystallization experiments have been carried out generating a temperature gradient ∆Т = 0 and without stirring of the reaction mass. Solid phase to liquid phase relation is 1:5. The hydrothermal synthesis was studied at a temperature of 80–200°C, a concentration of a crystallization solution of NaOH of 10–30% and a crystallization time of 10–48 hours. It is shown that the region of existence of zeolite of X with 100% crystallinity and phase purity is as follows: NaOH concentration – 15–20%; temperature – 90–110°C; processing time – 24 hours. The effect of temperature, concentration of crystallization solution, process time on crystallization was studied. It was found, that at temperatures below 90°С zeolite X+albite appeared in crystallization products, and above 110°С – zeolite X+anortite+analcime+chabazite+phillipsite; when the concentration of the crystallization solution is below 10%, low crystalline zeolite X (with 70% crystallinity)+albite, and above 20% – phillipsite+chabazite+zeolite X+analcime+hydrosodalite crystallizes; processing time below 10 hours crystallization process does not start and above 24 hours – analcime. The process of aging was studied in the duration interval from 1 to 3 days. It has been determined that an increase in the aging duration leads to an increase in the linear rate of crystallization of the X zeolite. The initial sample and the product obtained were studied by X-ray diffraction (2D PHASER «Bruker» (CuKα, 2θ = 20–80°)), IR-spectroscopy ((“Nicolete IS-10”), thermogravimetric (NETZSCH STA 449F3 STA449F3A-0757-M), elemental («Launch of Triton XL Ditution Refrigerator», Oxford Instrument) method of analysis and scanning electron microscopy (Hitachi TM-3000).