CHEMICAL BEHAVIOR OF LITHIUM IONS IN REEXPANDED LI-MONTMORILLONITES

Chemical behavior of lithium ions in reexpanded lithium-montmorillonit es has been investigated, their hydration capacity, interlamellar avai lability, and thermal reactivity being examined. Two experiments have been carried out: a thermal treatment to evaluate the possible recolla pse of the sample, and an ionic exchange with sodium ions followed by a further thermal treatment to analyze its exchange capacity. Samples obtained have been characterized by means of XRD, FTIR, DTA/TG, and Si -29, Al-27, and Li-7 MAS NMR. A complete recollapse of the sample afte r the thermal treatment and an extensive ionic exchange in NaCl soluti on were attained. The total reversibility of the process for lithium i ons has been concluded, although irreversible damage in the silicate l attice is observed.