Abstract:
The study of paste rheology is a hot and difficult point in the rheology of mining slurry. Paste technology includes four stages: dehydration, stirring, transportation and storage (filling), and all the stages involve rheological properties of non-Newtonian fluids. In the dewatering stage, the compressive yield stress of the whole tailings affects the dewatering concentration of the tailings mortar, and the concentration is the macroscopic expression of the shear yield stress, which in turn affects the shear yield stress of the slurry during mixing and pipeline transportation. Therefore, the relationship between compressive yield stress and shear yield stress has become a key issue in the field of paste filling technology. Under the guidance of pressure filtration theory, relevant experiments were carried out, and the characterization methods of bed dehydration resistance and slurry transportation performance in the full concentration range were put forward to characterize the thickening performance of full-tail mortar. The thickening performance of the whole tailings under high pressure is tested, and the compression yield stress of the whole tailings mortar under high pressure is obtained. Using controlled shear rate method (CSR) to operate paddle rheometer to detect shear yield stress; Then the relationship between them is obtained as follows: the yield stress of slurry is shear stress, and the compression yield stress is compression stress; Compressive yield stress and shear yield stress of slurry are exponentially related to concentration index. And the compression yield stress is far greater than the shear yield stress, so the shear action is more likely to destroy flocs, which is the main external force of dehydration, thus explaining the mechanical mechanism of stirring dehydration.
