Reciklaža i Održivi Razvoj (Jan 2018)
Micronization of zeolite in vibration mill
Abstract
Dry micronizing grinding of mineral raw materials is a very complex process and depends on a whole range of parameters such as: shape, particle size, size distribution of the starting and micronized material, hardness, moisture, density, surface properties, structural characteristics of mills, etc. In order to obtain a clear picture of dry micronizing milling process, a good knowledge of the theoretical principles of high-energy mills operation is necessary. Classical mills are not suitable for micronization to a fine and particularly very fine particles size (upper particle size limit below 5 μm), which is necessary for modern industrial application domains. The intensive fundamental and developmental research of the dry micronizing milling process for the new materials development has also enabled the development of new construction solutions for ultra-fine high-energy mills - mechanics. These mills have found application into the state-of-the-art production technologies of new very profitable materials. For the production of powders - particles of micron dimensions, the mechano-actuators are used and all micronizers - disintegrators, colloidal (perl mills), vibratory, planetary, ultra-centrifugal mill, Jet-current mills and others operate on the principle of impact, shock and friction. This paper presents the experimentally achieved results of dry micronizing grinding of zeolites in a vibrating mill with rings, as well as the improvement of its reactivity. All experimental micronization investigations were carried out on a previously prepared coarse particle size class (- 3.35 + 0) mm with different starting mass (50 g and 200 g), and carried out in different grinding time intervals (45, 120, 900 seconds), in order to examine the impact of these parameters on the micronization process. Grinding success was evaluated by the particle size measurements and content of class (- 5 + 0) μm, and particle specific surface. It was shown that for a sample of four times larger initial mass it is need longer grinding time to achieve the maximum content of the class (- 5 + 0) μm, but for a sample of the bulk class (- 3.35 + 0) mm with a lower starting mass the effects of amorphization due to prolonged micronizing grinding are very pronounced, and the zeolite minerals in crystalline form are practically in the trace and the largest part is amorphous. Generally, it can be concluded that a vibrating mill with a rings proved to be a good device for efficient ultra-fine micronizing grinding.
