Oil absorption of talc minerals and dispersant demand of talc mineral non-aqueous dispersions as a function of talc content: A surface chemistry approach

The effect of talc content on the oil absorption of talc minerals and on the dispersant demand of talc mineral non-aqueous dispersions was studied in terms of solid surface free energy. The van Oss-Chaudhury-Good (vOCG) theory was used to determine the Lifshitz-van der Waals/acid-base (LW/AB) components of talc minerals, employing two test liquid scales: the original vOCG scale and the Delia Volpe-Siboni (DVS) scale. The basic surface free energy component (gamma(-)) obtained from the DVS scale and the specific: surface area (S-BET) of talc minerals were used to calculate the basic specific free energy (G(sp)(-)), which showed a linear relationship with the oil absorption of talc mineral samples. The acidic specific free energy (G(sp)(+)) of talc minerals, obtained from both DVS and vOCG scales, showed a linear relationship with the dispersant demand of talc mineral non-aqueous dispersions. The correlation found for the dispersant demand and the oil absorption with the acidic and basic specific free energies, respectively, indicates that acid-base interactions play a key role in these talc mineral characteristics, which could be modified by changing the talc content of talc minerals. (c) 2006 Elsevier B.V. All rights reserved.