Author : Kamal S. Pak and Manar T. Nasser

This work deals with experimental study on the rheological behavior of polymer solutions, solid suspensions and the effect of adding polymers to solid suspensions. All polymers studied in this work are water soluble and used in industries as a rheology control additive (rheology modifiers), these are: Carboxymethyl cellulose (CMC), Xanthan Gum (XC), Hydroxyethyl cellulose (HEC), and Polyvinyl alcohol (PVA). Solid suspensions used are: Bentonite, Graphite and Corn starch. Experimens were performed with a concentration range of 4-40 g/L for CMC, HEC, XC, and 2-10 g/L for PVA, and the concentration range for solid suspensions were: Bentonite 50-120 g/L, Graphite 30-90 g/L and Corn Starch 300-800 g/L. It was found that as polymer concentration was increased, the flow behavior index (n) decreased, and the range of n was between 0.4 – 0.7 at 20°C. Increase the concentration of solid suspension causes the decrease of the flow behavior index (n), the range of n was between 1-1.3 at 35°C. The flow curves of polymer solutions and solid suspensions were studied using the power law model. By using the Solver Add-in in Microsoft Excel, the Bingham plastic model was found to be the best fits the experimental results of adding polymer to solid suspensions (PVA to Bentonite suspensions). The effect of adding PVA polymer on the rheological behavior of bentonite slurry was studied, it was found that the apparent viscosity of Bentonite/PVA decreases with increasing shear rate.

Keywords: Rheology, Apparent viscosity, Flow curves, Polymer solutions, Solid suspensions.