Sintering of nascent calcium oxide

✍ Scribed by Robert H. Borgwardt

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 899 KB
• Volume: 44
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(89)85232-7

✦ Synopsis

The sintering rate of calcium oxide in a nitrogen atmosphere was measured at temperatures from 700 to 1100°C. CaO prepared from ultrapure CaCO, was compared with impure CaO derived from limestone and calcium hydroxide. CaCO, derivatives yielded an initial surface area of 104 m'/g and the hydroxides, 76.7 m*/g. The rate of surface reduction was independent of particle size between 2 and 20 ,nm, but strongly dependent on temperature and impurities. Impurities increased the rate of sintering at a given temperature and reduced the activation energy. The model of German and Munir (J. Am. Ceram. Sot., 59, 379-383, 1976) correlates the kinetics ofsurface reduction and identifies lattice diffusion as the mechanism of solid transport. Porosity declined logarithmically with time during the intermediate stage of sintering.