Analysis of the research progress in the mechanism of particle mechanics action on the rheological behavior of paste in metal mines

The cemented paste backfill (CPB), a current research hotspot, is a safe, green, and efficient technical means to reduce cost and meet the requirements of solid waste treatment. The paste slurry is prepared from a variety of filling materials and later transported to the underground mining area through a pipeline; thus, it must meet the flow and transportation requirements. Additionally, the rheological properties of CPB significantly affect the flowability and transportability of the filling slurry, a key index to evaluate the performance of the filling slurry. However, due to the multiscale and high concentration of CPB, its rheological behavior is highly complex, and the existing rheological model is insufficient in describing the rheological behavior of the paste under shearing. The paste slurry will show a solid–fluid transition phenomenon at an ultralow shear rate, shear thinning at a steady-state shear, and shear thickening at a considerably high shear rate; the common rheological model can only be applied to the range of action of steady-state shear. Thus, the mechanism of the rheological behavior must be studied to identify the causes of the rheological model failure and discuss the fine mechanical mechanism between particles during shear. Conclusively, the interaction between the tailing particles and the tailing sand particles and water varying the overall friction coefficient of the paste with the application of shear rate is the root cause of the complex rheological behavior exhibited by CPB. By analyzing the limitations of the traditional paste rheological model, the domestic and international literature studies are reviewed based on the surface properties of particles and the interaction between the particles and water. First, the reasons for the formation of the hydrogen bond network structure on the surface of tailing particles and their influencing factors were analyzed. Next, the origin and variation of the microscopic friction force between particles under shearing influenced by the hydrogen bond network structure were described. The internal mechanisms of the rheological behaviors, including shear banding, shear thinning, and shear thickening, were analyzed, and the friction dissipation law of the paste rheological behavior with the changing shear rate was summarized. It is proposed that the accurate measurement of macroscopic friction is the key to analyzing its rheological behavior in the paste system, and clarification of the fine mechanical mechanism of complex rheological behavior promotes the development of metal ore paste rheology from macroscopic rheology to mesoscopic causation.