The Kinetics of the Ordering Process in Triclinic NaAlSi3O8

J. D. C. McConnell and Duncan Mckie
Dept. of Mineralogy and Petrology, Downing Place, Cambridge

Summary: A kinetic analysis is presented of the data of MacKenzie (1957) on the hydrothermal treatment of NaAlSi3O8 under isobaric, isothermal conditions in the temperature range 450° C. to 1000° C.

The analysis indicates the existence of a smeared polymorphic transformation in the temperature range around 600° C. The activation energy for the transformation is about 60 kcal. mole−1 and has been equated with the process of self-diffusion involved in Al-Si ordering in the structure. Some dry-heating experiments and the influence of varying water vapour pressure are discussed.

Mineralogical Magazine; June 1960 v. 32; no. 249; p. 436-454; DOI: 10.1180/minmag.1960.032.249.03
© 1960, The Mineralogical Society
Mineralogical Society (