Pengaruh Bentuk dan Panjang Batang dalam Menentukan Distribusi Ukuran Partikel Tepung Jagung Menggunakan Metode Pengapungan Batang (Buoyancy Weighing-Bar Method)

Abstract

One of the characteristics that determines the quality of particles is their size distribution. So far, various methods have been used to determine particle size. For solid liquid systems, the particle size distribution is measured using the Stokes diameter by measuring the speed of particle movement in solution. The method used to measure particle size distribution is the Andreasen Pipette, Sedimentation Balance Method. This method is a cheap method, but the process to obtain particle distribution results is quite long and not practical to operate. On the other hand, there are many other more efficient methods to obtain particle size distribution results, such as Laser Diffraction/Scattering, Microscopy and the Coulter Counter Method. Determination of particle size distribution has been carried out using equipment that is time consuming and expensive, one of which uses the laser difraction method. Therefore, the rod floatation method offers a solution with faster observation times and lower costs in determining particle size distribution. The sample material to be studied is corn flour. Ethanol is used as the liquid phase. The suspension concentration is 10 kg/m3 (± 1% by weight). Room temperature and liquid temperature are 298oK (room temperature). All suspensions were stirred before measurements. Measurement time is 2 hours. In this study, the particle size distribution was measured based on Stokes' law. For comparison, the results of this research were carried out using the Settling balance method. The rods used are made of aluminum and iron with a diameter of 10 mm and a density of 2.70×103 kg/m3. There is a hook at the bottom of the analytical scale (4 decimal places) for hanging the aluminum rod. To prepare the suspension, mix 1000 ml of liquid and particles in a measuring cup. Hang the rod under the analytical balance using a very light rope/thread. After stirring with a special stirrer, the rod was placed in suspension and recorded t = 0 s. This lasted for 2 hours and was recorded using a video recorder. After completing the measurement, measure the particle size distribution based on Equations 2.15, 2.16, and 2.17.