Large Strain Settling Behavior of Polymer-Amended Laterite Slurries: Fid-Bau Portal

Large Strain Settling Behavior of Polymer-Amended Laterite Slurries

Azam, Shahid

Knowledge of the settling properties of polymer-amended slurries is pivotal for improving throughput and yield during metal extraction and for developing tailings streams with superior geotechnical properties. This paper focuses on the large strain settling behavior of laterite slurries. The investigated slurry exhibited two settling regimes—sedimentation occurred up to e=em=8 and consolidation started at e=es=6.5. Bipower law functions best described the entire process in the form of e-σ^′ and k-e relationships. Polymer addition generally improved slurry compressibility and hydraulic conductivity. The settling behavior of polymer-amended slurries was governed by large interfloc voids during sedimentation and by small intrafloc pores during consolidation. The combined effect of polymer parameters was effectively captured by the term polymer characteristic coefficient. Fit parameters for the e-σ^′ and k-e relationships were directly proportional to Cp. Both the settling rate and amount varied extensively during hindered sedimentation. Compressibility during consolidation converged at σ^′=1,000 kPa and e=2, but this was not the case for hydraulic conductivity. Physicochemical interactions dominated sedimentation but were ineffective during consolidation. The liquid limit (σ^′=2 kPa) was used to differentiate between the two settling regimes.