Thermodynamic Properties of Potassium Metasilicate and Disilicate

Details

• Personal Author:
  Beyer, Richard P. ; Brown, Robert R. ; Daut, G. E. ; Ferrante, Michael J.
• Description:
  The Bureau of Mines has measured the low-temperature heat capacities and high-temperature enthalpies of crystalline k2si2o5 as part of a program for advancing mineral resources technology with energy economy. High-temperature enthalpies of glassy and liquid k2si2o5 and crystalline k2sio3 were also measured. An adiabatic calorimeter operation over the range 5 to 308 k was used for the heat capacity measurements for k2si205 from which the standard entropy at 298.15 K, s deg. 298 = 45.55 +/- 0.05 Cal/deg-mole, was calculated. Tabulated values of c deg. P, s deg., -(G deg. -H deg. 0)/T, and h deg. -H deg. O from 5 to 300 k are given for k2si2o5. A copper- block drop calorimeter was used in the enthalpy measurements, operating from 298.15 to 1,198 k for k2sio3 and from 298.15 To 1,453.8 K for k2si2o5. No transitions were found for k2sio3. The k2si2o5 showed two reversible first-order transitions, one at 510 k with a heat of transition of 0.29 Kcal/mole and one at 867 k with a heat of transition of 0.38 Kcal/mole. The heat of fusion for k2si2o5 was calculated to be 8.42 Kcal/mole. Relative enthalpies are given in equation form, and high-temperature values are tabulated for c deg. P, s deg., -(G deg. -H deg. 298)/T, and h deg. - H deg. 298. Also tabulated are ah deg., Ag deg., and log k for formation of k2sio3 and k2si2o5 from both the elements and the oxides. [Description provided by NIOSH]
• Subjects:
  Occupational Health Safety
• Series:
  Mining Publications
• Subseries:
  Report of Investigations
• Document Type:
  Text
• Genre:
  Conference Publications ; Case Report
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  ALRC - Albany Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-21
• NIOSHTIC Number:
  nn:10006822
• Federal Fiscal Year:
  1980
• Peer Reviewed:
  False
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:f502fb246bd6a1d3fb74f4159f91d652c71909c471b0cf4866d4ea2f34c49bdd2ba9e93b0b7c2df0db039e436c9caba81f1ea6995c3b7d7b461acdffd8fda071
• Download URL:
  https://stacks.cdc.gov/view/cdc/237250/cdc_237250_DS1.pdf
• File Type:
  [PDF - 6.58 MB ]