Effect of granulation time to particle size distribution of silica fertilizer from waste

Granulation is a process of increasing the size of particles, where small particles are agglomerated to form larger sizes. Silica fertilizer in the form of granules is made by directly mixing palm oil fuel ash (POFA) and fly ash with the addition of binder before processing in the pan granulator. The pan granulator output, in the form of wet granules, needs to be dried in an oven for 6 hours at 105°C. Then, a screener separated the dried granules according to their sizes. This study’s objective was to understand granulation time’s effect (20-35 minutes) on the particle size distribution of silica fertilizer granules. The samples were characterized in terms of average particle diameter and chemical contents using EDX. The result shows that the longer the granulation time of fly ash-based fertilizer, the more extensive particle size distribution will form a bigger granule size until it reaches the breakage phase. Meanwhile, the particle size distribution will create a smaller granule for the longer granulation time of POFA-based fertilizer. EDX result shows that the silica content in granules of fly ash is 37.664%, with an average particle diameter of approximately 3.1-4.6 mm. Based on POFA, the silica content in granules is 35.421%, with an average particle diameter of approximately 1.9-3.6 mm. The yield of the granulation process is approximately 54.04% to 82.51%.