方沸石水热制备白榴石（英文）

Preparation of Leucite from Analcime by Hydrothermal Method

采用水热法由方沸石和K_2CO_3反应合成可用于缓释型钾肥的白榴石。X射线衍射、扫描电子显微镜、Fourier转换红外线光谱分析和化学分析的结果表明:随着反应时间从1 h延长到3 h,钠的溶出率和K^+转化率随之上升,当到达10 h时趋于平稳。随着反应温度升高钾离子转化率增大。K_2CO_3浓度并不是越高越好,方沸石和K_2CO_3以摩尔比为1.0︰8.8在120℃反应4 h时,产物的K_2O含量最大为17.10%,此时钾的转化率为74.42%。动力学分析表明:化学反应速率由产物层扩散控制。

Leucite samples were prepared with analcime in K2CO3 solution by a hydrothermal method. Abundant K＋ in leucite is beneficial to the application in agriculture as a slow-releasing fertilizer. The samples were characterized by X-ray diffraction, Fourier transform infrared spectrometry, flame photometry and scanning electron microscopy, respectively. The results show that more leucite phases appear in the samples when the temperature increases. The conversion rate of K＋ increases as the reaction time increases from 1 h to 3 h. The content of K20 remains stable when the reaction time increases to 10 h. The maximum conversion rate ofK＋ is 74.42% when analcime reacts with 4 mol/L K2CO3 solution （KA1Si206/K2CO3 mole ratio=1.0：8.8） at 120 ℃ for 4 h. Based on the kinetic analysis by shrinking core model and the corresponding experiments, it is indicated the reaction rate could be controlled by product layer diffusion.