Enthalpy of formation of Fe 3 Al 2 Si 3 O 12 (almandine) by high temperature alkali borate solution calorimetry

Computer Science

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

7

Scientific paper

A high-temperature solution calorimetric method suitable for thermochemical studies of anhydrous minerals containing Fe 2+ ions has been developed. The method is based on an oxide melt solvent with 52 wt% LiBO 2 and 48 wt% NaBO 2 maintained at a temperature of 750°C. In a first application of this method the enthalpies of solution of synthetic almandine, fayalite, a mixture of fayalite plus quartz on FeSiO 3 composition, and natural quartz were measured. For the reaction: the enthalpy change at 1023 K is -3.82 ± 0.87 kcal, based on fayalite, quartz, corundum and almandine, and -5.96 ± 0.90 kcal based on the fayalite plus quartz mixture, corundum, and almandine. These values lead to standard molar enthalpies of formation of almandine from the oxides at 1023 K of -14.10 ± 1.22 kcal and -16.24 ± 1.74 kcal, respectively. The measured enthalpy of formation of almandine is less negative by several kilocalories than values derived from analysis of the phase equilibrium work of (1968), but in closer agreement with the phase equilibrium study of and (1979) and similar to the phase equilibrium deduction of (1973). The agreement of the present almandine enthalpy of formation with and (1979) and (1973) suggests that almandine entropies at 298 K to be obtained from their studies, in the range 79-81 cal/K, are more nearly correct than the several estimates based on oxide sum and volume-entropy systematics, most of which are much lower.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Enthalpy of formation of Fe 3 Al 2 Si 3 O 12 (almandine) by high temperature alkali borate solution calorimetry does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Enthalpy of formation of Fe 3 Al 2 Si 3 O 12 (almandine) by high temperature alkali borate solution calorimetry, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Enthalpy of formation of Fe 3 Al 2 Si 3 O 12 (almandine) by high temperature alkali borate solution calorimetry will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1467318

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.