The influence of temperature on particle size distribution of chalk suspension in the presence of a thermosensitive flocculant based on N-isopropylacrylamide and 3-(acryloyloxy)propanoic acid was investigated. No aggregation was observed at room temperature upon the addition of the polymer. When the system was heated, flocculation took place and the mean particle diameter was found to be temperature dependent. The polymer dosage influence on the process was examined. In higher polymer concentration the investigated process was fully reversible, i.e. aggregates broke upon cooling. The possibility to control particle size by temperature adjustment is discussed and die process' model is proposed. (C) 2010 Elsevier B.V. All rights reserved.