Effect of superplasticizer on rheology and thixotropy of superfine-tailings cemented paste backfill: Experiment and modelling

With the development of mineral processing technology, the tailings is becoming increasingly finer. In this study, the effect of superplasticizer (SP) dosage on dynamic and static rheological properties and thixotropic properties of superfine-tailings cemented paste backfill (SCPB) was explored. The applicability of water film thickness (WFT) model to rheological properties of SCPB was briefly assessed. Additionally, an improved dynamic yield stress model considering the water content within flocs was proposed for contributing to an in-depth understanding of the rheological behavior of SCPB or CPB. It is found that despite the significantly reduction in dynamic, static yield stress and equivalent plastic viscosity of SCPB with SP incorporation, there is a Critical Micelle Concentration that makes the characteristic time of the destructuration exhibit first an increasing and then decrease trend. Under steady-state shearing (100 s(-1)), the shear stress can be divided into three stages with time regardless of SP dosage. An exponential relationship is observed between the rheological parameters of SCPB and WFT. The proposed model can achieve high prediction accuracy and applicability. Moreover, the effective solid concentration and packing density in the model can be considered as the important parameters of high integration.