The Effect of Selective Additives on the Rheological Behavior of Power Plant Ash Slurry

The rheological behavior of power plant ash samples collected from JSPL (M/s Jindal Steel & Power Limited, Raigarh), India, was carried out using a HAAKE rotational rheometer (Model: RheoStress 1, Thermo Fisher Scientific). The ash slurry indicated non-Newtonian behavior in the solids concentration range of 50-60% by mass. The rheological data were best fitted by Bingham plastic model in the studied ranges of concentrations and shear rates. Two selective additives, namely sodium silicate and Ghadi detergent, were applied in small quantities (0-0.6% of total solids) and their effects on rheological parameters were evaluated. It was indicated that the small dosage of sodium silicate substantially influenced the Bingham parameters of the ash slurry than the Ghadi detergent. The percentage reduction in Yield stress at a slurry concentration of 60% by weight were found to be 59.3% and 46.23% for sodium silicate and Ghadi detergent, respectively, at a maximum dosage of 0.6% additives. More importantly, the plastic viscosity reduced by 37.6% and 16.3%, respectively, with the same dosage of sodium silicate and Ghadi detergent at same slurry concentration.