Rheological behaviour of nickel laterite suspensions

Studies have been conducted on rheology of nickel laterite suspension at different temperatures, concentrations, particle sizes and pH for both fines and tailings from a hydrocyclone discharge. Fine laterite slurries exhibit a Bingham plastic behaviour at 20% (w/w) solid concentration and above, while the same behaviour is observed for tailing slurries at > 25% (w/w) solid concentration. It is also observed that rheological parameters are affected by both pH and temperature. Both the Bingham viscosity and yield stress are minimum at around pH = 7 and the viscosity decrease with temperature is between 2- and 3-fold within the experimental range (20-60 degrees C). Further it is also observed that there is a steep increase in viscosity and yield stress between 45 and 50% (w/w) solid concentration. Correlations have been obtained for predicting both Bingham viscosity and yield stress taking into consideration, a non-dimensional parameter C-w/C-w,C-max, specific surface area and d(50). (C) 1998 Elsevier Science B.V. All rights reserved. discharge.