Size Reduction of Dolomite into Nano-Size Range through Milling and Tip-Sonication Processes

Abstract

Dolomite has great potential to be employed as filler or nanofiller in polymer composite/nanocomposite system. However, the research on dolomite as filler or nanofiller in polymer composite is still immature, requiring further investigations on how to optimize the dispersion of the dolomite in the polymer matrix, thus improving its properties. Particle size reduction of dolomite can be an efficient approach to increase its surface area and facilitate its dispersion and distribution within polymer matrix in order to develop homogeneous composite/nanocomposite system. In this study, the dolomite in pulverized form was obtained from Perlis Dolomite Industry, Malaysia with the average particle size of 150μm. In order to reduce the size of this dolomite, we have initially employed the planetary ball milling method. Results indicate that the particle size of dolomite has been reduced from 150μm to 2μm after subjected to ball milling process. This shows that upon ball milling procedure, the size of dolomite particle is still in micronmeter. Next, the ball milled dolomite was subjected to tip-sonication process to obtain dolomite in nanosize range. Several tip-sonication parameters, which were; amplitude and number of sonication repetition were applied in order to select the best parameters that can produce the finest dolomite powder. SEM and TEM were used to characterize the microstructure of the raw dolomite and the size reduced dolomite. Our results show that when the ball milled dolomite was tip-sonicated, much smaller particle size was obtained. Dolomite with the smallest particle size (~200nm) was obtained when the tip-ultrasonication was performed 3 times at amplitude of 50. These findings indicate that the combination of ball milling and tip-sonication is an efficient method to produce very fine dolomite particles, up to nanosize range. Furthermore, it is a clean, simple method and not involved any toxic and harmful chemicals.