Study of Zircon–Dolomite Reactions Monitored by Neutron Thermodiffractometry

✍ Scribed by José Luis Rodrı́guez; Antonio H. De Aza; Pilar Pena; Javier Campo; Pierre Convert; Xavier Turrillas

• Book ID: 102975052
• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 756 KB
• Volume: 166
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2002.9619

✦ Synopsis

The reaction mechanism that takes place in ZrSiO 4 -Mg Ca(CO 3 ) 2 mixtures was studied in air up to 13001C by collecting neutron diffraction patterns during the heating ramp. Neutron diffraction intensities were used to monitor and establish the mechanism of reaction that occurs in successive stages. (a) MgCa(CO 3 ) 2 decomposition yielding MgO and CaCO 3 ; (b) CaCO 3 decomposition; (c) reactions between CaO, MgO, and ZrSiO 4 involving the formation of phases such as: tetragonal-ZrO 2 , a-Ca 2 SiO 4 , and Ca 3 MgSi 2 O 8 , some of them acting as transitory phases; and (d) formation of CaZrO 3 . The results obtained by this technique agree with data obtained by differential thermal analysis and thermogravimetry. The final product has a porous structure, due to the release of CO 2 , with a very narrow pore size distribution (E1 lm). This open-porosity can be controlled by tailoring the reaction sintering process.