Controlling the elasticity of calcite suspensions by ionic species

Abstract

Calcite is an ubiquitous mineral employed in many industrial fields such as paper filling, pharmaceutical, art or construction. In particular the suspension of its particles is used to mimic early stage cementitious materials. In order to control the mechanical properties of calcite paste it is necessary to understand the role of the interaction forces between its particles. In this regard, this study show how a macroscopic quantity of the calcite suspensions, namely the elasticity, measured by rheological measurements can be linked to microscopic interactions, via DLVO analysis. Our calcite pastes are weakly attractive systems, showing a typical colloidal gel behavior, and characterized by an elastic shear modulus and a critical strain. We have tuned the interaction forces between particles by addition of simple ionic species (Ca2+ and OH−). Rheological measurements are compared to DLVO calculations, obtained by chemical speciations and ζ potential measurements on dense suspensions.