Low temperature exothermic effects on cooling of homoionic clays

► Homoionic montmorillonites and Na-kaolinite were investigated by use of DSC. ► Low temperature exothermic peaks were observed on cooling between − 33 and − 47 °C. ► Fields of the peak were cut proportionally to the extent of the previous warming. ► Stochastic deconvolution was applied to the endothermic peaks obtained on warming. ► Water, solidifying at the peaks, on warming melts in a wide temperature range.