Abstract: A method for preparing an exfoliated vermiculite, comprising the following steps: (a) a step of heating a non-exfoliated hydrated vermiculite at a temperature extending from 400 to 600° C. for a period extending from 3 hours to 7 hours, in this way generating a dehydrated vermiculite; and (b) a step of contacting the dehydrated vermiculite with a solution containing an intercalating agent capable of decomposing while generating gases.

Abstract: The invention relates to a process for converting an alkaline-earth metal chloride to at least one salt chosen from the tungstates and molybdates of this metal, which comprises the reaction of the alkaline-earth metal chloride with at least one precursor of tungsten or of molybdenum chosen from tungsten oxides, molybdenum oxides, tungstates and molybdates, this reaction being carried out in a solvent constituted by KCl or by an LiCl/KCl mixture and at a temperature at least equal to the melting point of this solvent. Applications: synthesis of alkaline-earth metal tungstates and molybdates, extraction of alkaline-earth metals from media in which they are found in the form of chlorides, recovery of alkaline-earth fission products from a salt flux in the context of the reprocessing of a spent nuclear fuel in molten chloride media, etc.