Flocculation process based on water soluble polymers as flocculating agents is still intensively researched nowadays, despite the introduction of these materials about fifty years ago. There is a need to gain the full control of this process in order to obtain high efficiency and strictly define products. For that purpose new solutions are proposed like stimuli-responsive macromolecules. In this paper the impact of suspension heating method on the flocculation process using thermosensitive polymer is reported. In experiments a model suspension of CaCO3 in RO water (purified by Reverse Osmosis) was destabilized using a copolymer of N-isopropylacrylamide (NIPAM) and cationic diallyldimethyl ammonium chloride (DADMAC).
The research was performed at the Department of Chemical and Process Engineering, Faculty of Chemistry, Silesian University of Technology (Poland). The laboratory setup consisted of a mixing tank with the Rushton turbine, laser particle sizer Fritsch Analysette 22, peristaltic pump and computer. Suspension was drawn from the mixer by tubes and circulated in a closed system. After examination in the laser particle size analyzer the suspension came back to the tank. Two different approaches were investigated in the experiments. Firstly, a gentle heating using an electric heater was used. Secondly, the rapid heating was employed by an injection of hot water directly into the suspension.