Flocculation and coagulation kinetics of Al2O3 suspensions

The effect of solid content on the structure of Al2O3 particle networks is studied by Brownian dynamics simulations using a novel interaction potential with image charges. Significant differences between 1 and 2 vol% suspensions are discussed with pair correlation functions, particle coordination numbers and cluster sizes. It is concluded, that the 2 vol% system is nearer to the percolation limit, thus fast aggregation occur. It is also stated, that the clustering dynamics should be described rather by the flocculation half-life than by the coagulation half-life. In real particle systems the interaction energy is not conservative due to friction with the medium. New expressions for the flocculation and coagulation half-life are derived using the interaction force as determining parameter, without the need for energy conservation. The corresponding coagulation half-life is compared with the classical expression of Fuchs.