High-temperature transformations of Zr-pillared bentonite

MARTINEZ, JUAN MANUEL; CONCONI, MARIA SUSANA; BOOTH, FERNANDO; RENDTORFF, NICOLÁS M.

JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY

SPRINGER

Lugar: Berlin; Año: 2020

1388-6150

A Zr-modified bentonite (B-OHZr) obtained by intercalation of OH-Zr species was obtained, and its thermal transformationsat > 800 °C were studied. Raw clay and B-OHZr were characterized by X-ray diffraction, thermogravimetric and differentialthermal analysis, and its sintering behavior was studied by hot-stage microscopy. Two Zr-based phases?tetragonal zirconiaand zircon?were observed in thermally treated B-OHZr with a sharp decrease in amorphous glassy phase in comparison withthe parental clay. An increase in refractoriness was observed in B-OHZr, enabling the sintering of samples up to 1300 °C,while the parental clay bloated and deformed with thermal treatment. The Zr interlayering enhanced the refractoriness athigh temperatures of the parental clay, eliminating thermal expansion (bloating) and enabling sintering at T > 1000 °C. Theobserved features and thermochemical processes enlighten the temperature usage range of these kinds of materials. Finallythese results yield promising features for potential use of these clays for the preparation of ceramic materials with zirconcontent.