Differential Thermal Analysis (DTA) Study of Kansas Montmorillonitic Clays from Phillips and Wallace Counties

Differential thermal analysis (DTA) curves of Kansas montmorillonites will most likely be those of an "abnormal" montmorillonite. No sample showed the single dehydroxylation reaction peak at 725°C of a normal montmorillonite. The predominant dehydroxylation reaction occurred at 525°C, although, especially in samples from Phillips County, two dehydroxylation peaks at 525° and 675°C were often present in a sample. Most curves had the typical two-peak endothermic water loss reactions in the 100-200°C range associated with calcium montmorillonite. Caliche (calcium carbonate) was a common impurity in Wallace County materials. All were very low in organic matter. Based on fired color, Wallace County material has a higher iron content than material from Phillips County