https://www.umsl.edu/~chickosj/JSCPUBS/dsccal.pdf

Reference materials for calorimetry and differential thermal analysis

A revised equation is proposed to represent and extrapolate the heat capacity of minerals as a function of temperature: C
P=k0+k1
T
−0.5+k2
T
−2+k3
T
−3 (where k1, k2≤0). This equation reproduces calorimetric data within the estimated precision of the measurements, and results in residuals for most minerals that are randomly distributed as a function of temperature. Regression residuals are generally slightly greater than those calculated with the five parameter equation proposed by Haas and Fisher (1976), but are significantly lower than those calculated with the three parameter equation of Maier and Kelley (1932). The revised equation ensures that heat capacity approaches the high temperature limit predicted by lattice vibrational theory (C
P=3R+α2VT/β). For 16 minerals for which α and β have been measured, the average C
Pat 3,000 K calculated with the theoretically derived equation ranges from 26.8±0.8 to 29.3±1.9 J/(afu·K) (afu = atoms per formula unit), depending on the assumed temperature dependence of α. For 91 minerals for which calorimetric data above 400 K are available, the average C
Pat 3,000 K calculated with our equation is 28.3±2.0 J/(afu·K). This agreement suggests that heat capacity extrapolations should be reliable to considerably higher temperatures than those at which calorimetric data are available, so that thermodynamic calculations can be applied with confidence to a variety of high temperature petrologic problems. Available calorimetric data above 250 K are fit with the revised equation, and derived coefficients are presented for 99 minerals of geologic interest. The heat capacity of other minerals can be estimated (generally within 2%) by summation of tabulated ‘oxide component’ C
Pcoefficients which were obtained by least squares regression of this data base.

/pdf/heat-capacity-of-minerals-in-the-system-na-2-o-k-2-o-cao-mgo-41pin1q2iw.pdf

Heat capacity of minerals in the system Na 2 O-K 2 O-CaO-MgO-FeO-Fe 2 O 3 -Al 2 O 3 -SiO 2 -TiO 2 -H 2 O-CO 2 : representation, estimation, and high temperature extrapolation

Quantitative kinetic and structural analysis of geopolymers. Part 1. The activation of metakaolin with sodium hydroxide

Free energy dependence of albite dissolution kinetics at 80°C and pH 8.8

Thermodynamic modelling of alkali-activated slag cements

Calorimetric measurements have been carried out on a pure speciment of analcime whose composition was Na/sub 0.96/Al/sub 0.96/Si/sub 2.04/O/sub 6/.H/sub 2/O and on the corresponding anhydride. The low-temperature heat capacity, standard enthalpy of formation (298.15 K), and high-temperature enthalpy increments have been determined by adiabatic, solution, and drop-calorimetric techniques, respectively. Thermodynamic functions have been calculated for analcime (to 600 K) and for dehydrated analcime (to 1000 K).

/pdf/thermodynamic-studies-of-zeolites-analcime-and-dehydrated-3gcnf4tkx8.pdf

Thermodynamic studies of zeolites: analcime and dehydrated analcime

Calorimetric measurements have been carried out on specimens of natrolite, mesolite, and scolecite in order to assess the thermodynamic properties of a zeolite series having the same alumino-silicate framework. Low-temperature heat capacity and high-temperature enthalpy increments of natrolite and scolecite were measured by adiabatic and drop-calorimetric techniques. Standard enthalpies of formation at 298.15 K of all three zeolites were determined by solution calorimetry. Thermodynamic functions have been calculated for natrolite to 660 K and for scolecite to 470 K. The heat capacity and standard entropy at 298.15 K have been estimated for mesolite. With reference to zeolitic water, it is concluded that the entropy of water molecules in both natrolite and scolecite is similar to that in ice. A consideration of the X-ray results for the present specimen of natrolite leads to the conclusion that a contribution of about 9.2 J/(mol x K) to the standard entropy is made by the Al-Si disorder in the alumino-silicate framework. The new results allow calculations to be made by which the pressure and temperature effect can be deduced for such equilibria as: natrolite + SiO/sub 2/(aq) = 2 analcime, and natrolite + Ca/sup 2 +/(aq) + H/sub 2/O = mesolite + 2Na/sup +/(aq).more » Results are consistent with observed parageneses in natural occurrences. 21 references, 1 figure, 10 tables.« less

/pdf/thermodynamic-studies-of-zeolites-natrolite-mesolite-and-15h78llmxj.pdf

P. A. G. O'Hare

Papers

Thermodynamic studies of zeolites: analcime and dehydrated analcime

Thermodynamic studies of zeolites; natrolite, mesolite and scolecite