The effect of coal particle aggregation on the sedimentation and rheology of coal—oil mixtures

• Published in: Colloids and surfaces 1982, Vol.4 (3), p.245-254
• Main Authors: Adams-Viola, M., Botsaris, G.D., Filymer, W.G., Glazman, Yu.M., King, K.D.
• Format: Article
• Language: English
• ISSN: 0166-6622; 1873-4340
• DOI: 10.1016/0166-6622(82)80021-8

The degree of coal particle aggregation in model oil suspension was assessed by particle size distribution using a sedimentation balance. Various statistical parameters were calculated for three suspensions each prepared with Sewell coal, model oil, and (1) calcium petroleum sulfonate (2) no additive and (3) an ethoxylated quartenary ammonium salt. These formulations represented suspensions which were (1) aggregatively stable (2) slightly aggregated and (3) highly aggregated, respectively. Batch settling tests were also conducted with the three formulations at coal concentrations of 10, 35 and 50%. These results indicated that the clarity of the supernatant, the initial settling velocity and the terminal sediment volume increased as the degree of aggregation increased. Rheological data indicated that the aggregatively stable suspensions were Newtonian but that pseudoplasticity and yield stresses were observed in the other formulations to an extent which increased as the degree of aggregation increased.