Effects of Temperature on the Flocculation Processes of Kaolinite in the Quiescent Water

Abstract

The settling and flocculation play important roles in the cohesive sediment transport. An experimental study on the settling and flocculation of kaolinite in a cylindrical settling column was carried out. Six temperature conditions of 5°C, 10°C, 15°C, 20°C, 25°C and 30°C were chosen to clarify the influences of temperature on the flocculation of kaolinite in the quiescent water. A three-dimensional numerical model for simulating the coagulation processes of colloids has been performed based on the lattice Boltzmann method by the floc settling velocity under various temperatures. Results show that the settling velocity increases with the increase of temperature under the given sediment concentration. When the temperature is higher than 25°C, the increasing rate of the settling velocity is accelerated obviously. And the settling velocity in salt water with the salinity of 5 ppt is faster than that in fresh water under the same conditions. Furthermore, an empirical formula for the settling velocity of kaolinite considering effects of temperature is proposed.