Heterogeneous flow of filling slurry under shear: an explanation of its nonlinear rheological properties

Cemented filling technology serves as an efficient method for addressing tailings and enhancing the stability of goafs, establishing itself as a crucial application in metal mining operations. The mixing stage is pivotal in preparing the filling slurry, as it directly impacts the slurry working performance. The rheological properties of slurry are critical indicators of its mixing quality, influenced by various factors. To elucidate the meso-mechanical effects on these rheological properties, this study conducted macroscopic rheological experiments to derive the flow curve of slurries and employed low-field nuclear magnetic resonance experiments to quantify water distribution within the slurry. The study revealed that post-mixing, the slurry exhibited significant nonlinear rheological behaviors. Furthermore, the low-field nuclear magnetic resonance results indicated that changes in material conditions led to notable alterations in the strength of particle interactions. By integrating experimental findings, the analysis delved into inter-particle interactions, highlighting that colloidal forces, hydration forces, and friction forces predominantly govern these interactions. Ultimately, by understanding the modes of particle contact, the meso-mechanical underpinnings of the slurry's rheological properties were clarified. These insights offer valuable guidance for optimizing the mixing process and controlling the rheological behavior of filling slurries in metal mining, paving the way for more efficient and stable applications.