Table 2 DTA endothermic peaks recorded in the raw material and the mixtures and their interpretations
From: Phosphogypsum waste as additives to lime stabilization of bentonite
Samples | Endothermic peaks (°C) | Mass loss (%) | Interpretations |
|---|---|---|---|
Bentonite | 135 | 10 | Desorption of physisorbed water molecules. |
520, 680 | 3.61, 1.17 | Dehydroxylation of montmorillonite and the quartz transformation from α to β. | |
Lime | 500 | 13 | Decomposition of portlandite on hydrated lime (Ca(OH)2). |
780 | 10 | Calcite dycarboxylation. | |
PG | 180 | 20 | Gypsum dehydration (CaSO4·2H2O → γ-CaSO4). |
475, 780 | 23 | Portlandite decomposition (Ca(OH)2 → CaO + H2O). | |
Bentonite + 8% Lime | 135 | 10 | Desorption of physisorbed water molecules. |
500, 675 | 10 | Dehydroxylation of montmorillonite and the quartz transformation from α to β. | |
Bentonite + 8% Lime + 8% PG | 150 | 10 | Desorption of physisorbed water molecules. |
515, 665 | 9 | Dehydroxylation of montmorillonite and the quartz transformation from α to β. |