Effect of poly-acrylic acid (PA) additives on the rheology of coal water slurries

Recently coal water slurry (CWS) is restarted to arouse people´s attention. With the development of CWS technology, many additives were researched. Based on lots of experiments, poly-acrylic acid (PA) additives were synthesized. In this paper, the rheology of coal water slurries from two Chinese coal samples by adding PA additives and naphthalene additive respectively are studied. Under the same conditions, for Baori and Changcun coal samples, comparing with naphthalene, the dosage of PA additives in CWS lowers 40%~51% and the coal concentration of CWS increased by 1%~5%. Based on the analysis of structure characteristic of PA, it is speculated that the better rheology of CWS adding PA additives was because they had flexible structure and more adsorptive sites and could adsorb on the surface of coal effectively and enhance the hydrophilicity of coal surface obviously.