An experimental platform of spray agglomeration has been designed and built for removing small fly ash particles (PM10) from coal combustion. Agglomerating model of fine particles during the spray process was developed by combining rapid coagulation theory and analysis of the interaction between droplets and particulates. Systematic experiments were conducted in multistage spouted tower using several kinds of agglomerant solutions. The influencing factors such as surfactant, pH value, flow rate of agglomerant solutions and inlet flue gas temperature were analyzed. SEM was used to analyze the microstructure of the aggregation. Based on this model, coagulation rate constant was calculated and the influences of original parameters were observed. The spray agglomeration mechanism of particles can be analyzed from both macroscopical and microcosmic aspects. Preliminary results are presented and discussed in this work. Final results indicate that the special shape of multistage spouted fluidized tower has significant influences on the effect of agglomeration. The findings from this work will be helpful to form the basis and provide guidance for further studies on the control of fine particles such as PM2.5 or even smaller ones. (C) 2009 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.