Improvement in properties of coal water slurry by combined use of new additive and ultrasonic irradiation.

Coal water slurry (CWS) was prepared with a newly developed additive from naphthalene oil. The effects of ultrasonic irradiation on coal particle size distribution (PSD), adsorption behavior of additive in coal particles and the characteristics of CWS were investigated. Results showed that ultrasonic irradiation led to a higher proportion of fine coal in CWS and increased the saturated adsorption amount of additive in coal particles. In addition, the rheological behavior and static stability of CWS irradiated by ultrasonic wave were remarkably improved. The changes on viscosity of CWS containing 1% and 2% additive are qualitatively different with the increasing sonication time studied. The reason for the different effect of sonication time on CWS viscosity is presented in this study.