The evolution of textural properties of Na/Ca-bentonite from W yoming (MX-80) was studied by adsorption of nitrogen, water vapour, and ethylene glycol monoethyl ether. Clay suspensions were heated at 80
and 300ºC for up to 9 months in the absence of or in the presence of Fe and/or Fe oxides. The treatment without Fe did not change the textural properties of the samples significantly. The treatment
at 80ºC in the presence of Fe resulted in a considerable increase in the external surface areas of the samples. The total and external surface areas and swelling capacities of the samples decreased
following the treatment at 300ºC in the presence of Fe and Fe oxides. In the case of larger additions of Fe, the treatment at 300ºC resulted in a considerable decrease in the total and external
surface areas and swelling capacity of the sample and in the formation of a network of large-size pores, in which all the pores were connected.