Castable surface chemistry

Surface Chemistry as a Tool for the Development of Advanced Refractory Castables... 

Advanced refractory castables usually display a broad particle size distribution and, therefore, contain a large fraction of micron- and submicron-sized particles (0.1-100 p,m) in combination with coarse aggregates (> 100 xm). Consequently, aspects of the surface chemistry and, thus, the dispersion state of the smaller particles (matrix) in water also play a major role in the processing and final properties of these refractory materials (10-15). 

This section presents a general overview on the mode of action of dispersants in refractory castables, focusing especially on the ability of these molecules to adsorb and modify the surface chemistry of particles (Parts A—C), the secondary effects that may arise from the addition of dispersants to the castable matrix (Part D), the possible interactions between dispersants and cement particles (Part E), and novel routes that have been applied to design the dispersant molecule in order to optimize the rheological behavior of castables and concretes (Part F). 

Basic concepts of surface chemistry are outlined in this chapter to understand the mechanisms that can be applied to optimize the dispersion and rheological behavior of advanced refractory castables. The modes of action of some dispersants are described to illustrate the effects of some of their molecular features (chain length, functional groups, charge density) on the dispersion state of matrix... 

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