Chemical reactivity of thermally activated clay minerals estimation by dissolution in hydrofluoric acid
✍ Scribed by M. Murat; M. Driouche
- Publisher
- Elsevier Science
- Year
- 1988
- Tongue
- English
- Weight
- 312 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0008-8846
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✦ Synopsis
The rapid estimation of the chemical reactivity of transitory phases (TACM synthetic pozzolanlc binders) obtained by Thermal Activation of Clay Minerals between 500"C and IO00"C, can be obtained in less than one hour, using the • = f(t) conductlmetrlc curve associated to the congruent dissolution in dllute hydrofluoric acid at 25"C. Investigations on thermally activated kaolinite and montmorlllonite has allowed to point out sensitive differences in the dissolution process according to the structure of the raw-materlal the recorded • = f(t) curve is a two steps and a continuous one for kaolinite and montmorillonite, respectively. Two different specific parameters can be measured either the conductivity variation associated to the first dissolution step, or the slope of the curve at time t=O (initial dissolution rate). These parameters can be correlated to the short-tlme strength development of calcium hydroxyde-actlvated TACM binders, and have their maximal values for the thermal activation temperature which leads to the optimum disorganization state of the solid.