The silica (.alpha.-cristobalite) dissolution in 8 and 11 wt% of sodium hydroxide solutions (2.17 or 3.08 mol L 1, respectively) was followed by microcalorimetry at temperature ranging between 80 and 130 C. The global enthalpies of the process are equal to 15.13 and 17.51 kJ mol 1, respectively. A kinetic scheme based on two successive first-order reactions has been proposed, and thermochemical and kinetic parameters were iteratively deduced. The former are generally in accordance with the experimental values. The isoconversional model showed that the activation energy of silica dissolution varies with the conversion degree and ranges in the interval 72 97 kJ mol 1. It reaches a maximum corresponding to a minimum dissolution speed, which moves toward lower conversion fraction values when the concentration of NaOH solution increases.
Compounds
#
Formula
Name
1
HNaO
sodium hydroxide
2
O2Si
silicon dioxide
3
H2O
water
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.