Improving of Thixotropic Properties of Bentonite Dispersions in Rheological Applications

In this study, the improvement of the rheological properties of bentonites by alkaline activation was investigated. The characterizations of the samples used in the study were determined by X-ray fluorescence spectroscopy (XRF), particle size distribution (PSD), cation exchange capacity (CEC), specific surface area (SSA) analysis and scanning electron microscopy (SEM) images. The rheological properties of the suspensions were determined by apparent viscosity (AV), plastic viscosity (PV), yield point (YP) and gel strength (GS) measurements. In addition, static filtration analysis was performed and thixotropic properties were determined by shear thinning index (STI) and thixotropy index (TI) calculations. Rheological flow parameters were calculated using the least squares method (LSM) and the model equations were created according to the Herschel-Bulkley flow model (HBM). As a result of the analyzes, it was determined that the alkaline activation process improved the rheological and thixotropic properties of bentonite dispersions. Also, the rheogram curves indicate that the suspensions showed a shear-thinning flow behavior. In the HBM evaluation, it was determined that the best flow properties belonged to EB (0.9987 R2) in raw samples and NB (0.9985 R2) in activated samples.