Clays and derived products in polyphased materials

Résumé En

Clays minerals used as components of polyphased materials range from undifferentiated dilution products to specific materials as reinforcement fillers. They are essential parts of processes and their unit volume cost is sometimes higher than that of the matrix they enter ; then the technical improvement they bring must counterbalance their processing and compounding cost. Clay producers act as technical advisers, by proposing to their customers products adjusted step by step and whose use allows less expensive formulations. This completely empirical approach can be rationalized in three steps. 1) — Analysis of the variability of the benefitting material. 2) — Definition of an application test 3) — Measurement of technical properties. After that, statistical processing of data gives keys to define the ideal substances and to evaluate the existing ones. Although this method allows successful handling of complex systems without knowing the physical rules that govern them, it is not explicative enough to ensure real technical progress and must be completed by research on the origin of the behaviour trends. This is the task of scientists ; it needs a permanent come and go between fundamental and applied domains and a global and concerted contribution of numerous specialists.