Various cation-exchanged montmorillonites (Li+, Na+, Ba2+, Mg2+, Ca2+, Mn2+, Co2+, Cu2+, Ag+, Cd2+, Hg2+, Al3+, Pb2+ and NH4+)
were prepared from calcium montmorillonite and their properties were studied by means of X-ray diffraction and thermal analysis.
The two methods give information on the cation exchange in the interlayer space only. X-ray diffraction studies at room temperature
are mainly suitable for estimation of the exchange of cations of different valencies. At 500C, when the structure is completely
collapsed, the d value of montmorillonite depends on the non-hydrated ionic radius of the interlayer cation, but the measurement
interval is limited for fine interpretation. The thermoanalytical method is suitable for a better distinction of different
exchangeable cations of higher hydration energy on the basis of the DTG or DDTG curve.