Mössbauer Studies of Iron in Illite and Montmorillonite. II. Thermal Treatment

抄録

Three-layer type iron bearing minerals, Illite and Montmorillonite after different chemical treatments, were heated over a range of temperatures 100–950°C, with a view to study the migration of Fe³⁺ ions from the sites of their take-up and to examine the thermal stability of these clays. The increased temperature causes the progressive depletion of iron ions from the broken edges and consequent reinforcement of the iron population in the basal plane. In both the cases, the acid treatment weakens the structure whereas Fe(NO₃)₃ treatment reinforces it. On treatment with acid, Montmorillonite, with its capacity to expand along C-axis, is amenable to the creation of lattice defects in the Si-tetrahedra.