Dewatering Behaviour of a Uranium Ore Slurry Containing Clays: Fid-Bau Portal

Dewatering Behaviour of a Uranium Ore Slurry Containing Clays

Ito, Maki / Azam, Shahid

Abstract The main objective of this paper was to investigate the dewatering behaviour of a clayey uranium ore slurry. The slurry (containing 28% clay size) exhibited moderate water adsorption (wl = 83% and wp = 30%). Primarily composed of muscovite (46%) and quartz (30%), the clay minerals included illite (8%), chlorite (5%) and kaolinite (2%) alongside a CEC of 41 (cmol(+)/kg) with $ Ca^{2+} $ and $ Mg^{2+} $ as the dominant cations. Likewise, the high EC (17,600 μS/cm) and ionic strength (1.15 mol/L) indicated a flocculated microstructure due to the presence of $ SO_{4} $2− (22,600 mg/L) and $ Mg^{2+} $ (1340 mg/L) in the slurry water. Settling included sedimentation and consolidation at low initial solids condition (25–35%) whereas only consolidation was observed at high initial solids contents (40–50%). The average k reduced from 1.2 × $ 10^{−6} $ m/s (initial s = 25%) to 5.3 × $ 10^{−8} $ m/s (initial s = 50%) along with a void ratio reduction from 7.4 to 2.6. Due to thixotropic strength, volume compressibility during consolidation showed apparent pre-consolidation at low effective stress (0.3–2 kPa) with a reduction in void ratio from 2.6 to 2.5. The es was found to be 2.46 at σ′ = 2 kPa and was followed by a steeper slope with the void ratio reducing to 2.1 at σ′ = 31 kPa. Likewise, the hydraulic conductivity during consolidation decreased from 2.6 × $ 10^{−9} $ m/s (at e = 2.6) to 2.0 × $ 10^{−10} $ m/s (at e = 2.1).