Production of highly soluble foliar fertilizer in a spouted bed dryer

Abstract

The drying process can be useful to change the particulate structure, improving the powder solubility. In this study, we investigated the drying of foliar fertilizer in a spouted bed using polyethylene pellets as inert particles to improve its solubility. A 23 factorial experimental design was used to evaluate how the powder yield and moisture were affected by the feeding time, intermittency time, and feed atomizer position. The spouting instability caused powder retention on the bed wall, which decreased the powder recovery efficiency by 2.3-26.6%. Although the powder recovery efficiency was low, the solubility time was reduced by 5.9 times, probably due to particle agglomeration, which increased the amorphous phase of the fertilizer. Design alterations, suggested by the CFD data, can increase spouted bed stability and facilitate centralized spouting. Based on this, the spouted bed drying technique was applied, and it effectively increased the solubility of commercial fertilizer, thus, incorporating more desirable characteristics for field applications.