Silica–paraffin and kaolin–paraffin dispersions: Use of rheological and calorimetric methods to investigate the nature of their dispersed microstructure units

Immersion Calorimetric Method to Study Lime Surfaces Impurities and Particles Aggregate Morphologies

“…All these values show that the interactions between the paraffin molecules and the CaO surfaces are weak [31], and strongly suggest that the dispersed microstructure units of the limes have a morphology quite similar to that observed in a detailed analysis of the dried powders [20].…”

“…A Setaram C80 calorimeter described in a recent paper [20] and equipped with stainless steel wetting cells were used in these experiments. Two identical cells (measure and reference) were placed in the calorimetric block at a temperature of 30±0.01°C.…”

“…The open ampoule was filled with the sample and connected to a mechanical vacuum system before sealing with a butane flame. The final object, approximately 5-6 cm in height, was introduced in the calorimeter cell previously described [20].…”

“…Calorimetry tests were performed to measure the heat of dispersion in liquid paraffin [17,20,22] of the CaObased oxides.…”

“…This method had been applied by others authors [18,19] to obtain information on the nature of the surface chemical and physical properties of colloidal particles dispersed in a selected liquid phase. In one of our recent papers [20], we studied the dispersions of silica and kaolin powders in liquid paraffin as a function of their solid volume fraction and we proved that the corresponding exothermic wetting heat and/or the specific wetting heat ξ (J/m 2 ) can account for the network formed by the particle aggregates in the dispersing liquid. The application of these principles to the colloidal CaO-paraffin system allows to discuss the solid-liquid interfaces, only in term of van der Waals and steric forces, due to the absence of aromatic and/or of naphthenic groups in the paraffin chains [21].…”