Rheological behaviour of nickel laterite suspensions

Abstract

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.