Determination of the limit concentration of structured suspension according to the theory of lyophobic colloids stability

Abstract

The article investigates the influence of structured suspensions of ion-electrostatic and Van der Waals nature forces characteristics and parameters of the solid and liquid phases on the maximum achievable concentration of structured suspensions. Based on the analysis of lattice structure options formed by particles of solid phase of suspension, an assessment of possible scenarios for the disruption of the stable suspension structure has been conducted. It is shown that the least likely disruption of the stable suspension structure is the penetration of neighboring particles onto the edges of the lattice structure. The most probable disruption of the stable suspension structure is due to the penetration of particles from the nodes of neighboring lattice cells onto the diagonals lying in the planes of the faces of the considered cube, or onto the diagonals lying in the planes of the faces of this cube. This leads to a reduction in the distance between neighboring particles to values that induce irreversible and reversible coagulation processes. A method for assessing the concentration of the equilibrium state is proposed, that is, the volumetric fraction of the solid phase in a structured suspension at which the distance between two neighboring particles corresponds to a state of stable equilibrium, depending on the value of the parameter of energy interaction between particles at different values of their effective dimensionless diameter. An estimate of the corrective coefficient of the maximum achievable concentration of suspensions was obtained, which allows determining the concentration of the suspension at which fluidity and stability are maintained, depending on the parameters of ion-electrostatic and Van der Waals forces, as well as the maximum possible volumetric concentration of the suspension. Using the formulas proposed in the work, methods for controlling the processes of preparing a structured suspension can be justified, ensuring its aggregate stability, static and dynamic sedimentation stability, by choosing the particle size and concentration of the solid phase, taking into account the parameters of ion-electrostatic and Van der Waals nature. Further development of mathematical models for controlling the stable structure of suspensions was obtained, which for the first time allows determining possible scenarios of irreversible and reversible coagulation for a given concentration and particle size of the solid phase. Keywords: structured suspension, concentration, pipeline, inverse Debeye radius, Hamaker constant.