Effects of mechanical activation on the parameters of talc quality for ceramics production - Chemometric approach

Abstract

Talc is broadly used in the ceramic materials industry, either as a basic raw material, or as filler, due to its chemical inertia, fragmentation proneness, thermal stability, and refractoriness. The mechanical activation is frequently employed in the direct enhancement of talc properties, and thereby in the design of talc based composites with advanced performances. The differences in the set of the process parameters measured before and after talc activation via ultra-centrifugal mill Retsch ZM-1, and their influence on the grain-size distribution related characteristics have been investigated. The mechanical treatments are energetically unsustainable procedures, therefore the talc activation was optimized on basis of assessment of the process variables (number of rotor revolutions, current intensity, activation period, circumferential rotor speed and mill capacity) effect on the final quality of product parameters (mesh sizes, cumulative oversizes, average grain size, level of micronization kinetics, mesh size appropriate to 95% micronized product cumulative undersize and specific surface area). The activated product parameters in all experimental sequences were obtained by the analytical procedure based on Rosin-Rammler-Sperling equation. Response surface method, standard score analysis and principal component analysis were used as a means of the optimization. Developed models showed r(2) values in the range of 0.714-0.908 and they were able to accurately predict quality parameters in a wide range of process parameters. Standard score analysis highlighted that the optimal sample was obtained using sieve mesh of 120 mu m set of processing parameters (SS = 1.0). Multiple comparison tests revealed that the optimal variation in the processing parameters could reduce the negative effect of talc samples inherent properties on the final score and improve the activation procedure energetic and economic sustainability.