This paper deals with the effect of some physicochemical factors on flocculation of fine particle suspension produced during pyrometallurgical processing of nickeliferous laterite. Off-gases dust from the pre-reduction step and flocculants of various ionic characters were used in this study. The effect of suspension pH and temperature as well as of polymer dosage and concentration of polymer solution added on settling rate and supernatant concentration in solids was examined. The results show that the increase of temperature and pH establish a more negative charge on the particles mixture, so rendering the cationic flocculants more effective. On the other hand, both polymer dosage and concentration (or dilution) of the added polymer solution affect significantly the settling rate of the suspension as well as the clarity of the supernatant. (C) 2005 Elsevier B.V. All rights reserved.