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以煤系高岭土为原料,经煅烧、酸浸脱铝工艺,首次在酸浸偏高岭土-碱水热反应体系中合成了NaY分子筛.采用XRD,SEM对所合成样品进行表征,考察了体系中碱度、硅铝比、老化过程、晶化过程对NaY分子筛合成的影响.结果表明:该水热反应体系适宜的碱度条件为n(H2O)/n(Na2O)=80,碱度过高或过低均会出现P型分子筛杂相.适宜的硅铝配比为n(SiO2)/n(Al2O3)=6.4;老化有助于生成纯相、结晶度好的NaY分子筛,其适宜的老化温度为50℃、老化时间为4h.晶化温度过高或晶化时间过长易转晶生成P型杂相,适宜的晶化条件是晶化温度为85℃、晶化时间为24h.在该反应体系中反应原料由偏高岭土酸浸脱铝后获得,产物结晶度较高,无杂晶,晶形完整,粒度为2μm左右.
NaY zeolite was synthesized for the first time in acid-leaching metakaolin-alkali hydrothermal reaction system by using calcined kaolin as raw material, and calcined and acid-treated aluminum removal process.The synthesized samples were characterized by XRD and SEM, and the effects of alkali Degree of Si / Al ratio, aging process and crystallization process on the synthesis of NaY zeolite were investigated.The results showed that the optimum alkalinity conditions for the hydrothermal reaction system were n (H2O) / n (Na2O) = 80, If the temperature is too low, the heterogeneous phase of P-type molecular sieve will appear, and the suitable ratio of silicon to aluminum is n (SiO2) / n (Al2O3) = 6.4. Aging contributes to the formation of NaY zeolite with pure phase and good crystallinity. Is 50 ℃, the aging time is 4h.The crystallization temperature is too high or the crystallization time is too long to easily transform into P-type hetero-phase, the suitable crystallization conditions are the crystallization temperature is 85 ℃, the crystallization time is 24h. In the reaction system, the reaction raw materials are obtained by acid leaching and delamination of metakaolin, and the product has high crystallinity, no impurity and no crystal grains, and the crystal shape is complete, and the particle size is about 2 μm.