High-stress permeability and consolidation characteristics of flocculanted fine tailings.

Fine-grained tailings have poor permeability and a long consolidation time, but treatment with flocculants can improve their mechanical properties. Changes in the physical and engineering properties of fine tailings due to treatment with different flocculants was investigated by microscope observations, settling tests and tests for shear strength, consolidation and permeability. A new concept – the relative flocculation rate Fr – was used to quantify the effect of flocculation on the hydraulic conductivity and void ratio of coarse tailings, fine tailings and flocculant-treated tailings under high pressure using a developed high-stress permeability and consolidation apparatus. The results showed that a composite flocculant could have a considerable effect on the geotechnical properties of fine tailings due to changes in the double diffusion layer (DDL) of the particles. However, for a consolidation pressure greater than 2 MPa, the DDL theory is no longer applicable. [ABSTRACT FROM AUTHOR]