The present position of the theory of the coagulation of dilute clay suspensions A résumé.

Abstract

In this paper the general theory of the coagulation of dilute clay suspensions is discussed. The more important of the points considered are summarised below.1. Two separate mechanisms causing collisions between suspended particles are considered, namely their Brownian motion and the mass motion of one group of particles relative to another group. Following Wiegner, these two types of collision are called perikinetic and orthokinetic collisions respectively. The rate of coagulation of a suspension is then shown to depend on the rate of collisions between particles and on the probability of adhesion between them when they collide. If this probability is unity, that is if every collision between two particles results in their adhesion, the suspension is undergoing rapid coagulation. There is excellent agreement between theory and experiment for this type of coagulation whenever the mathematical equations involved can be solved. But if the probability of adhesion is less than unity, the suspension is undergoing slow coagulation, and there is as yet no theory capable of giving the rate of coagulation of such a system.