Top-down approach has been viewed as an efficient and straightforward method to prepare nanosized zeolites. Yet, the mechanical breaking of zeolite causes amorphization, which usually requires a post-milling recrystallization to obtain fully crystalline nanoparticles. Herein we present a facile methodology to prepare zeolite nanocrystals, where milling and recrystallization can be performed in situ. A milling apparatus specially designed to work under conditions of high alkalinity and temperature enables the in situ recrystallization during milling. Taking zeolite A as an example, we demonstrate its size reduction from ~3 μm to 66 nm in 30 min, which is quite faster than previous methods reported. Three functions, viz., miniaturization, amorphization and recrystallization were found to take effect concurrently during this one-pot process. The dynamic balance between these three functions was achieved by adjusting the milling period and temperature, which lead to the tuning of zeolite A particle size. Particle size and crystallinity of the zeolite A nanocrystals were confirmed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and water adsorption-desorption. This work presents a pioneering advancement in this field of nanosized zeolites, and will facilitate the mass production as well as boost the wide applications of nanosized zeolites.

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Dry bead mills are believed to contribute significantly to the shortening of drying processes and reduction of required production space, as well as the energy costs reductions that result from these improvements. In this study, we used a dry bead mill to perform grinding test on silica sand, alumina, and activated carbon. We investigated the impact various dry bead mill conditions had on grinding, and explored the dry grinding potential of bead mills. We found a regular relationship between the median diameter and the power, and that this tended to match previous reports. We also demonstrated that within the scope of this experiment, tip speed, bead filling, and the feed rate were not factors that affected the energy efficiency.

In order to minimize the amount of dragout and to obtain the reproducible data, behaviors of factors affecting the drawing amount should be studied. Among many factors involved, physical properties of plating solution, such as viscosity and surface tension, and the shape of edge of specimen were investigated in the present study.The effect of viscosity on the amount of dragout changes according to the speed of withdrawal or to the thickness of the liquid film. Decrease of surface tension increases the volume of drainage and decreases the volume of bead on the edge. With the surface tension less than 40 dyne/cm the amount of bead of edge becomes constant regardless of thickness of adhearing film. The amount of bead of the dragout is generally more than 50% of that of static drainage.

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