Saponite differential thermal analysis

The differential thermal analysis (DTA) curves in Figures 5-2 and 5-3, and the X-ray diffractograms in Figure 5-4 show the occurrence and identification of the major phases formed on heating. All clays show a sharp endotherm between 100-2(K) C due to sorbed water losses. In Figure 5-2A the desorption endotherm, with a peak minimum at 760°C, represents the saponite dehydro rlation and collapse of the dehydrated silicate matrix. The exotherm at 805 C is attributed to orthorhombic enstatite (MgSiOj) formation smaller (and... 

Figure 5-2. Differential thermal analysis (DTA) curves of a sample of thetic saponite before (A) and after expansion with Si02 Ti02 clusters, followed (B) air drying or (C) supercritical drying with CO2.

On differential thermal curves for vermiculites and saponites, as already mentioned, a small endothermic peak can occur at about 600°C associated with a small exothermic peak at 800 to 900°C. This normally indicates the interstratification of some brucite layers (see Figure 20), but these are frequently so few (or incomplete) and so randomly interstratified that their presence is not revealed on the X-ray pattern. Differential thermal analysis is, therefore, a particularly sensitive method of detection. 

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See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

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