Table 3 Peak temperatures of DSC endotherms for all samples and all four oven pressures used, arranged in order of increasing peak temperatures at 1000 mbar
Sample | Decomposition type (source of gas released) | DSC peak temperature (°C) | |||
|---|---|---|---|---|---|
12 mbar | 30 mbar | 150 mbar | 1000 mbar | ||
Epsomite | H2O (structural H2O) | 94.2 | 107.9 | 103.1 | 127.8 |
Montmorillonite | H2O (cation solvation water) | 87.3 | 97.9 | 111.6 | 135.0 |
Goethite | H2O (structural OH) | 297.8 | 304.4 | 312.0 | 327.4 |
Kieserite | H2O (structural H2O) | 392.7 | 394.8 | 395.4 | 404.4 |
Kaolinite | H2O (structural OH) | 503.6 | 506.3 | 509.5 | 524.7 |
Alunite | H2O (structural OH) | 563.4 | 564.3 | 566.9 | 570.0 |
Magnesite | CO2 loss (carbonate decomposition) | 595.0 | 605.3 | 615.3 | 628.6 |
Alunite | H2O (structural OH) | 631.8 | 637.1 | 642.6 | 642.3 |
Montmorillonite | H2O (structural OH) | 699.3 | 702.2 | 712.1 | 763.9 |
Alunite | SO2 loss (sulfate decomposition) | 767.6 | 766.1 | 769.2 | 782.6 |
Calcite (<150 μm) | CO2 loss (carbonate decomposition) | 719.0 | 736.2 | 766.2 | 807.0 |
Calcite (3 mm crystals) | CO2 loss (carbonate decomposition) | 933.7 | 938.3 | 954.9 | 971.7 |
Epsomite | SO2 loss (sulfate decomposition) | 951.9 | 972.3 | 1033.4 | 1105.7 |
Kieserite | SO2 loss(sulfate decomposition) | 1062.6 | 1081.8 | 1100.4 | 1162.1 |