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根据分子表面扩散理论提出了NH_4Cl与NaY固相离子交换过程的机理,推导了固相离子交换过程中界面扩散过程和粒内扩散过程的动力学模型。本研究将NH_4Cl-NaY机械研磨混合物在一定温度下进行固相离子交换,采用~(23)Na核磁共振法测定固相离子交换度,分别考察了在100℃、150℃、200℃下进行固相离子交换时,固相离子交换度与时间的关系,得出固相离子交换动力学曲线,根据理论分析的动力学模型对固相离子交换动力学曲线进行拟合,得出了NH_4Cl-NaY固相离子交换在反应初期由界面扩散控制、在交换反应中后期由粒内扩散控制的结论。
According to the theory of molecular surface diffusion, the mechanism of solid phase ion exchange between NH_4Cl and NaY was proposed, and the kinetic model of interfacial diffusion and intragranular diffusion during the solid phase ion exchange was deduced. In this study, NH_4Cl-NaY mechanical milling mixture was subjected to solid-phase ion exchange at a certain temperature, and the degree of solid-phase ion exchange was measured by ~ (23) Na nuclear magnetic resonance method. The solid phase ion exchange degree was investigated respectively at 100 ℃, 150 ℃ and 200 ℃ Phase ion exchange, the relationship between solid phase ion exchange rate and time, the kinetic curve of solid-phase ion exchange was obtained. According to the kinetic model of the theoretical analysis, the solid-phase ion exchange kinetic curve was fitted, and the NH_4Cl-NaY The solid-phase ion exchange is controlled by interface diffusion in the initial stage of the reaction, and controlled by intragranular diffusion in the late stage of the exchange reaction.